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diff --git a/42860-0.txt b/42860-0.txt index 939352d..92ed524 100644 --- a/42860-0.txt +++ b/42860-0.txt @@ -1,26 +1,4 @@ -The Project Gutenberg EBook of The Andes of Southern Peru, by Isaiah Bowman - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org/license - - -Title: The Andes of Southern Peru - Geographical Reconnaissance along the Seventy-Third Meridian - -Author: Isaiah Bowman - -Release Date: June 2, 2013 [EBook #42860] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK THE ANDES OF SOUTHERN PERU *** - - - +*** START OF THE PROJECT GUTENBERG EBOOK 42860 *** Produced by Chuck Greif, The University of Florida Digital Collections and the Online Distributed Proofreading Team @@ -13501,365 +13479,4 @@ observation the value of which is S. 16° 37′ 00″. 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You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org/license - - -Title: The Andes of Southern Peru - Geographical Reconnaissance along the Seventy-Third Meridian - -Author: Isaiah Bowman - -Release Date: June 2, 2013 [EBook #42860] - -Language: English - -Character set encoding: ISO-8859-1 - -*** START OF THIS PROJECT GUTENBERG EBOOK THE ANDES OF SOUTHERN PERU *** - - - - -Produced by Chuck Greif, The University of Florida Digital -Collections and the Online Distributed Proofreading Team -at http://www.pgdp.net - - - - - -Transcriber's note: The etext attempts to replicate the printed book as -closely as possible. Obvious errors in spelling and punctuation have -been corrected. The spellings of names, places and Spanish words used by -the author have not been corrected or modernized by the etext -transcriber. The footnotes have been moved to the end of the text body. -The images have been moved from the middle of a paragraph to the closest -paragraph break for ease of reading. - - [Illustration] - - - - - THE ANDES OF SOUTHERN - PERU - - GEOGRAPHICAL RECONNAISSANCE ALONG THE - SEVENTY-THIRD MERIDIAN - - BY - - ISAIAH BOWMAN - Director of the American Geographical Society - - [Illustration: colophon] - - PUBLISHED FOR - THE AMERICAN GEOGRAPHICAL SOCIETY - OF NEW YORK - - BY - - HENRY HOLT AND COMPANY - - 1916 - - LATIN - AMERICA - - COPYRIGHT, 1918 - - BY - - HENRY HOLT AND COMPANY - - THE QUINN & BODEN CO. PRESS - RAHWAY, N.J. - - TO - - C. G. B. - - - - -PREFACE - - -The geographic work of the Yale Peruvian Expedition of 1911 was -essentially a reconnaissance of the Peruvian Andes along the 73rd -meridian. The route led from the tropical plains of the lower Urubamba -southward over lofty snow-covered passes to the desert coast at Camaná. -The strong climatic and topographic contrasts and the varied human life -which the region contains are of geographic interest chiefly because -they present so many and such clear cases of environmental control -within short distances. Though we speak of "isolated" mountain -communities in the Andes, it is only in a relative sense. The extreme -isolation felt in some of the world's great deserts is here unknown. It -is therefore all the more remarkable when we come upon differences of -customs and character in Peru to find them strongly developed in spite -of the small distances that separate unlike groups of people. - -My division of the Expedition undertook to make a contour map of the -two-hundred-mile stretch of mountain country between Abancay and the -Pacific coast, and a great deal of detailed geographic and physiographic -work had to be sacrificed to insure the completion of the survey. Camp -sites, forage, water, and, above all, strong beasts for the -topographer's difficult and excessively lofty stations brought daily -problems that were always serious and sometimes critical. I was so -deeply interested in the progress of the topographic map that whenever -it came to a choice of plans the map and not the geography was first -considered. The effect upon my work was to distribute it with little -regard to the demands of the problems, but I cannot regret this in view -of the great value of the maps. Mr. Kai Hendriksen did splendid work in -putting through two hundred miles of plane-tabling in two months under -conditions of extreme difficulty. Many of his triangulation stations -ranged in elevation from 14,000 to nearly 18,000 feet, and the cold and -storms--especially the hailstorms of mid-afternoon--were at times most -severe. - -It is also a pleasure to say that Mr. Paul Baxter Lanius, my assistant -on the lower Urubamba journey, rendered an invaluable service in -securing continuous weather records at Yavero and elsewhere, and in -getting food and men to the river party at a critical time. Dr. W. G. -Erving, surgeon of the Expedition, accompanied me on a canoe journey -through the lower gorge of the Urubamba between Rosalina and the mouth -of the Timpia, and again by pack train from Santa Ana to Cotahuasi. For -a time he assisted the topographer. It is due to his prompt surgical -assistance to various members of the party that the field work was -uninterrupted. He was especially useful when two of our river Indians -from Pongo de Mainique were accidentally shot. I have since been -informed by their _patrón_ that they were at work within a few months. - -It is difficult to express the gratitude I feel toward Professor Hiram -Bingham, Director of the Expedition, first for the executive care he -displayed in the organization of the expedition's plans, which left the -various members largely care-free, and second, for generously supplying -the time of various assistants in the preparation of results. I have -enjoyed so many facilities for the completion of the work that at least -a year's time has been saved thereby. Professor Bingham's enthusiasm for -pioneer field work was in the highest degree stimulating to every member -of the party. Furthermore, it led to a determination to complete at all -hazards the original plans. - -Finally, I wish gratefully to acknowledge the expert assistance of Miss -Gladys M. Wrigley, of the editorial staff of the American Geographical -Society, who prepared the climatic tables, many of the miscellaneous -data related thereto, and all of the curves in Chapter X. Miss Wrigley -also assisted in the revision of Chapters IX and X and in the correction -of the proof. Her eager and in the highest degree faithful assistance in -these tasks bespeaks a true scientific spirit. - -ISAIAH BOWMAN. - - -SPECIAL ACKNOWLEDGMENTS FOR ILLUSTRATIONS - -Fig. 28. Photograph by H. L. Tucker, Engineer, Yale Peruvian Expedition -of 1911. - -Fig. 43. Photograph by H. L. Tucker. - -Fig. 44. Photograph by Professor Hiram Bingham. - -Figs. 136, 139, 140. Data for hachured sketch maps, chiefly from -topographic sheets by A. H. Bumstead, Topographer to Professor Bingham's -Peruvian Expeditions of 1912 and 1914. - - - - -CONTENTS - - -PART I - -HUMAN GEOGRAPHY - -CHAPTER PAGE - -I. THE REGIONS OF PERU 1 - -II. THE RAPIDS AND CANYONS OF THE URUBAMBA 8 - -III. THE RUBBER FORESTS 22 - -IV. THE FOREST INDIANS 36 - -V. THE COUNTRY OF THE SHEPHERDS 46 - -VI. THE BORDER VALLEYS OF THE EASTERN ANDES 68 - -VII. THE GEOGRAPHIC BASIS OF REVOLUTIONS AND OF HUMAN -CHARACTER IN THE PERUVIAN ANDES 88 - -VIII. THE COASTAL DESERT 110 - -IX. CLIMATOLOGY OF THE PERUVIAN ANDES 121 - -X. METEOROLOGICAL RECORDS FROM THE PERUVIAN ANDES 157 - - -PART II - -PHYSIOGRAPHY OF THE PERUVIAN ANDES - -XI. THE PERUVIAN LANDSCAPE 183 - -XII. THE WESTERN ANDES: THE MARITIME CORDILLERA OR CORDILLERA -OCCIDENTAL 199 - -XIII. THE EASTERN ANDES: THE CORDILLERA VILCAPAMPA 204 - -XIV. THE COASTAL TERRACES 225 - -XV. PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 233 - -XVI. GLACIAL FEATURES 274 - - -APPENDIX A. SURVEY METHODS EMPLOYED IN THE CONSTRUCTION OF -THE SEVEN ACCOMPANYING TOPOGRAPHIC SHEETS 315 - -APPENDIX B. FOSSIL DETERMINATIONS 321 - -APPENDIX C. KEY TO PLACE NAMES 324 - -INDEX 327 - - -TOPOGRAPHIC SHEETS - -Camaná Quadrangle 114 - -Aplao " 120 - -Coropuna " 188 - -Cotahuasi " 192 - -La Cumbre " 202 - -Antabamba " 282 - -Lambrama " - - - - -PART I - -HUMAN GEOGRAPHY - - - - -CHAPTER I - -THE REGIONS OF PERU - - -Let four Peruvians begin this book by telling what manner of country -they live in. Their ideas are provincial and they have a fondness for -exaggerated description: but, for all that, they will reveal much that -is true because they will at least reveal themselves. Their opinions -reflect both the spirit of the toiler on the land and the outlook of the -merchant in the town in relation to geography and national problems. -Their names do not matter; let them stand for the four human regions of -Peru, for they are in many respects typical men. - - -THE FOREST DWELLER - -One of them I met at a rubber station on the lower Urubamba River.[1] He -helped secure my canoe, escorted me hospitably to his hut, set food and -drink before me, and talked of the tropical forest, the rubber business, -the Indians, the rivers, and the trails. In his opinion Peru was a land -of great forest resources. Moreover, the fertile plains along the river -margins might become the sites of rich plantations. The rivers had many -fish and his garden needed only a little cultivation to produce an -abundance of food. Fruit trees grew on every hand. He had recently -married the daughter of an Indian chief. - -Formerly he had been a missionary at a rubber station on the Madre de -Dios, where the life was hard and narrow, and he doubted if there were -any real converts. Himself the son of an Englishman and a Chilean woman, -he found, so he said, that a missionary's life in the rubber forest was -intolerable for more than a few years. Yet he had no fault to find with -the religious system of which he had once formed a part; in fact he had -still a certain curious mixed loyalty to it. Before I left he gave me a -photograph of himself and said with little pride and more sadness that -perhaps I would remember him as a man that had done some good in the -world along with much that might have been better. - -We shall understand our interpreter better if we know who his associates -were. He lived with a Frenchman who had spent several years in Africa as -a soldier in the "Foreign Legion." If you do not know what that means, -you have yet all the pleasure of an interesting discovery. The Frenchman -had reached the station the year before quite destitute and clad only in -a shirt and a pair of trousers. A day's journey north lived a young -half-breed--son of a drunken father and a Machiganga woman, who cheated -me so badly when I engaged Indian paddlers that I should almost have -preferred that he had robbed me. Yet in a sense he had my life in his -hands and I submitted. A German and a native Peruvian ran a rubber -station on a tributary two days' journey from the first. It will be -observed that the company was mixed. They were all Peruvians, but of a -sort not found in such relative abundance elsewhere. The defeated and -the outcast, as well as the pioneer, go down eventually to the hot -forested lands where men are forgotten. - -While he saw gold in every square mile of his forested region, my -clerical friend saw misery also. The brutal treatment of the Indians by -the whites of the Madre de Dios country he could speak of only as a man -reviving a painful memory. The Indians at the station loved him -devotedly. There was only justice and kindness in all his dealings. -Because he had large interests to look after, he knew all the members of -the tribe, and his word was law in no hackneyed sense. A kindlier man -never lived in the rubber forest. His influence as a high-souled man of -business was vastly greater than as a missionary in this frontier -society. He could daily illustrate by practical example what he had -formerly been able only to preach. - -[Illustration: Fig. 1--Tropical vegetation, clearing on the river bank -and rubber station at Pongo de Mainique. The pronounced scarp on the -northeastern border of the Andes is seen in the right background.] - -[Illustration: Fig. 2--Pushing a heavy dugout against the current in the -rapids below Pongo de Mainique. The indian boy and his father in the -canoe had been accidentally shot.] - -[Illustration: Fig. 3--From the sugar cane, Urubanba Valley, at Colpani. -On the northeastern border of the Cordillera Vilcapampa looking -upstream. In the extreme background and thirteen sixteens of an inch -from the top of the picture is the sharp peak of Salcantay. Only the -lower end of the more open portion of the Canyon of Torontoy is here -shown. There is a field of sugar cane in the foreground and the valley -trail is shown on the opposite side of the river.] - -He thought the life of the Peruvian cities debasing. The coastal -valleys were small and dry and the men who lived there were crowded and -poor (sic). The plateau was inhabited by Indians little better than -brutes. Surely I could not think that the fine forest Indian was lower -than the so-called civilized Indian of the plateau. There was plenty of -room in the forest; and there was wealth if you knew how to get at it. -Above all you were far from the annoying officials of the government, -and therefore could do much as you pleased so long as you paid your -duties on rubber and did not wantonly kill too many Indians. - -For all his kindly tolerance of men and conditions he yet found fault -with the government. "They" neglected to build roads, to encourage -colonization, and to lower taxes on the forest products, which were -always won at great risk. Nature had done her part well--it was only -government that hindered. Moreover, the forested region was the land of -the future. If Peru was to be a great nation her people would have to -live largely upon the eastern plains. Though others spoke of "going in" -and "coming out" of the rubber country as one might speak of entering -and leaving a dungeon, he always spoke of it as home. Though he now -lived in the wilderness he hoped to see the day when plantations covered -the plains. A greater Peru and the forest were inseparable ideas to him. - - -THE EASTERN VALLEY PLANTER - -My second friend lived in one of the beautiful mountain valleys of the -eastern Andes. We walked through his clean cacao orchards and cane -fields. Like the man in the forest, he believed in the thorough -inefficiency of the government; otherwise why were there no railways for -the cheaper transportation of the valley products, no dams for the -generation of power and the storage of irrigation water, not even roads -for mule carts? Had the government been stable and efficient there would -now be a dense population in the eastern valleys. Revolutions were the -curse of these remote sections of the country. The ne'er-do-wells became -generals. The loafer you dismissed today might demand ten thousand -dollars tomorrow or threaten to destroy your plantation. The government -troops might come to help you, but they were always too late. - -For this one paid most burdensome taxes. Lima profited thereby, not the -valley planters. The coast people were the favored of Peru anyhow. They -had railroads, good steamer service, public improvements at government -expense, and comparatively light taxes. If the government were impartial -the eastern valleys also would have railways and a dense population. Who -could tell? Perhaps the capital city might be here. Certainly it was -better to have Lima here than on the coast where the Chileans might at -any time take it again. The blessings of the valleys were both rich and -manifold. Here was neither a cold plateau nor the hot plains, but -fertile valleys with a vernal climate. - -We talked of much else, but our conversation had always the pioneer -flavor. And though an old man he saw always the future Peru growing -wonderfully rich and powerful as men came to recognize and use the -resources of the eastern valleys. This too was the optimism of the -pioneer. Once started on that subject he grew eloquent. He was -provincial but he was also intensely patriotic. He never missed an -opportunity to impress upon his guests that a great state would arise -when people and rulers at last recognized the wealth of eastern Peru. - - -THE HIGHLAND SHEPHERD - -The people who live in the lofty highlands and mountains of Peru have -several months of real winter weather despite their tropical latitude. -In the midst of a snowstorm in the Maritime Cordillera I met a solitary -traveler bound for Cotahuasi on the floor of a deep canyon a day's -journey toward the east. It was noon and we halted our pack trains in -the lee of a huge rock shelter to escape the bitter wind that blew down -from the snow-clad peaks of Solimana. Men who follow the same trails are -fraternal. In a moment we had food from our saddle-bags spread on the -snow under the corner of a _poncho_ and had exchanged the best in each -other's collection as naturally as friends exchange greetings. By the -time I had told him whence and why in response to his inevitable -questions we had finished the food and had gathered a heap of _tola_ -bushes for a fire. The _arriero_ (muleteer) brought water from a spring -in the hollow below us. Though the snow thickened, the wind fell. We -were comfortable, even at 16,000 feet, and called the place "The -Salamanca Club." Then I questioned him, and this is what he said: - -"I live in the deep valley of Cotahuasi, but my lands lie chiefly up -here on the plateau. My family has held title to this _puna_ ever since -the Wars of Liberation, except for a few years after one of our early -revolutions. I travel about a great deal looking after my flocks. Only -Indians live up here. Away off yonder beyond that dark gorge is a group -of their huts, and on the bright days of summer you may see their sheep, -llamas, and alpacas up here, for on the floors of the watered valleys -that girdle these volcanoes there are more tender grasses than grow on -this _despoblado_. I give them corn and barley from my irrigated fields -in the valley; they give me wool and meat. The alpaca wool is most -valuable. It is hard to get, for the alpaca requires short grasses and -plenty of water, and you see there is only coarse tufted ichu grass -about us, and there are no streams. It is all right for llamas, but -alpacas require better forage. - -"No one can imagine the poverty and ignorance of these mountain -shepherds. They are filthier than beasts. I have to watch them -constantly or they would sell parts of the flocks, which do not belong -to them, or try to exchange the valuable alpaca wool for coca leaves in -distant towns. They are frequently drunk." - -"But where do they get the drink?" I asked. "And what do you pay them?" - -"Oh, the drink is chiefly imported alcohol, and also _chicha_ made from -corn. They insist on having it, and do better when I bring them a little -now and then. They get much more from the dealers in the towns. As for -pay, I do not pay them anything in money except when they bring meat to -the valley. Then I give them a few _reales_ apiece for the sheep and a -little more for the llamas. The flocks all belong to me really, but of -course the poor Indian must have a little money. Besides, I let him have -a part of the yearly increase. It is not much, but he has always lived -this way and I suppose that he is contented after a fashion." - -Then he became eager to tell what wealth the mountains contained in soil -and climate if only the right grasses were introduced by the government. - -"Here, before us, are vast _punas_ almost without habitations. If the -officials would bring in hardy Siberian grasses these lava-covered -plateaus might be carpeted with pasture. There would be villages here -and there. The native Indians easily stand the altitude. This whole -Cordillera might have ten times as many people. Why does the government -bother about concessions in the rubber forests and roads to the eastern -valleys when there are these vast tracts only requiring new seeds to -develop into rich pastures? The government could thus greatly increase -its revenues because there is a heavy tax on exported wool." - -Thus he talked about the bleak Cordillera until we forgot the pounding -of our hearts and our frequent gasps for breath on account of the -altitude. His rosy picture of a well-populated highland seemed to bring -us down nearer sea level where normal folks lived. To the Indians the -altitude is nothing. It has an effect, but it is slight; at any rate -they manage to reproduce their kind at elevations that would kill a -white mother. If alcohol were abolished and better grasses introduced, -these lofty pastures might indeed support a much larger population. The -sheep pastures of the world are rapidly disappearing before the march of -the farmer. Here, well above the limit of cultivation, is a permanent -range, one of the great as well as permanent assets of Peru. - - -THE COASTAL PLANTER - -The man from the deep Majes Valley in the coastal desert rode out with -me through cotton fields as rich and clean as those of a Texas -plantation. He was tall, straight-limbed, and clear-eyed--one of the -energetic younger generation, yet with the blood of a proud old family. -We forded the river and rode on through vineyards and fig orchards -loaded with fruit. His manner became deeply earnest as he pictured the -future of Peru, when her people would take advantage of scientific -methods and use labor-saving machinery. He said that the methods now in -use were medieval, and he pointed to a score of concrete illustrations. -Also, here was water running to waste, yet the desert was on either -hand. There should be dams and canals. Every drop of water was needed. -The population of the valley could be easily doubled. - -[Illustration: FIG. 4--Large ground moss--so-called _yareta_--used for -fuel. It occurs in the zone of Alpine vegetation and is best developed -in regions where the snowline is highest. The photograph represents a -typical occurrence between Cotahuasi and Salamanca, elevation 16,000 -feet (4,880 m.). The snowline is here at 17,500 feet (5,333 m.). In the -foreground is the most widely distributed _tola_ bush, also used for -fuel.] - -[Illustration: FIG. 5.--Expedition's camp near Lamgrama, 15,500 feet -(4,720 m.), after a snowstorm The location is midway in the pasture -zone.] - -[Illustration: FIG. 6--Irrigated Chili Valley on the outskirts of -Arequipa. The lower slopes of El Misti are in the left background. The -_Alto de los Huesos_ or Plateau of Bones lies on the farther side of the -valley.] - -[Illustration: FIG. 7--Crossing the highest pass (Chuquito) in the -Cordillera Vilcapampa, 14,500 feet (4,420 m.). Grazing is here carried -on up to the snowline.] - -Capital was lacking but there was also lacking energy among the people. -Slipshod methods brought them a bare living and they were too easily -contented. Their standards of life should be elevated. Education was -still for the few, and it should be universal. A new spirit of progress -was slowly developing--a more general interest in public affairs, a -desire to advance with the more progressive nations of South -America,--and when it had reached its culmination there would be no -happier land than coastal Peru, already the seat of the densest -populations and the most highly cultivated fields. - - * * * * * - -These four men have portrayed the four great regions of Peru--the -lowland plains, the eastern mountain valleys, the lofty plateaus, and -the valley oases of the coast. This is not all of Peru. The mountain -basins have their own peculiar qualities and the valley heads of the -coastal zone are unlike the lower valleys and the plateau on either -hand. Yet the chief characteristics of the country are set forth with -reasonable fidelity in these individual accounts. Moreover the spirit of -the Peruvians is better shown thereby than their material resources. If -this is not Peru, it is what the Peruvians think is Peru, and to a high -degree a man's country is what he thinks it is--at least it is little -more to him. - - - - -CHAPTER II - -THE RAPIDS AND CANYONS OF THE URUBAMBA - - -Among the scientifically unexplored regions of Peru there is no other so -alluring to the geographer as the vast forested realm on the eastern -border of the Andes. Thus it happened that within two weeks of our -arrival at Cuzco we followed the northern trail to the great canyon of -the Urubamba (Fig. 8), the gateway to the eastern valleys and the -lowland plains of the Amazon. It is here that the adventurous river, -reënforced by hundreds of mountain-born tributaries, finally cuts its -defiant way through the last of its great topographic barriers. More -than seventy rapids interrupt its course; one of them, at the mouth of -the Sirialo, is at least a half-mile in length, and long before one -reaches its head he hears its roaring from beyond the forest-clad -mountain spurs. - -The great bend of the Urubamba in which the line of rapids occurs is one -of the most curious hydrographic features in Peru. The river suddenly -changes its general northward course and striking south of west flows -nearly fifty miles toward the axis of the mountains, where, turning -almost in a complete circle, it makes a final assault upon the eastern -mountain ranges. Fifty miles farther on it breaks through the long -sharp-crested chain of the Front Range of the Andes in a splendid gorge -more than a half-mile deep, the famous _Pongo de Mainique_ (Fig. 9). - -Our chief object in descending the line of rapids was to study the -canyon of the Urubamba below Rosalina and to make a topographic sketch -map of it. We also wished to know what secrets might be gathered in this -hitherto unexplored stretch of country, what people dwelt along its -banks, and if the vague tales of deserted towns and fugitive tribes had -any basis in fact. - -[Illustration: FIG. 8--Sketch map showing the route of the Yale-Peruvian -Expedition of 1911 down the Urubamba Valley, together with the area of -the main map and the changes in the delineation of the bend of the -Urubamba resulting from the surveys of the Expedition. Based on the -"Mapa que comprende las ultimas exploraciones y estudios verificados -desde 1900 hasta 1906," 1:1,000,000, Bol. Soc. Geogr. Lima, Vol. 25, No. -3, 1909. For details of the trail from Rosalina to Pongo de Mainique see -"Plano de las Secciones y Afluentes del Rio Urubamba: 1902-1904," scale -1:150,000 by Luis M. Robledo in Bol. Soc. Geogr. Lima, Vol. 25, No. 4, -1909. Only the lower slopes of the long mountain spurs can be seen from -the river; hence only in a few places could observations be made on the -topography of distant ranges. Paced distances of a half mile at -irregular intervals were used for the estimation of longer distances. -Directions were taken by compass corrected for magnetic deviation as -determined on the seventy-third meridian (See Appendix A). The position -of Rosalina on Robledo's map was taken as a base.] - -We could gather almost no information as to the nature of the river -except from the report of Major Kerbey, an American, who, in 1897, -descended the last twenty miles of the one hundred we proposed to -navigate. He pronounced the journey more hazardous than Major Powell's -famous descent of the Grand Canyon in 1867--an obvious exaggeration. He -lost his canoe in a treacherous rapid, was deserted by his Indian -guides, and only after a painful march through an all but impassable -jungle was he finally able to escape on an abandoned raft. Less than a -dozen have ventured down since Major Kerbey's day. A Peruvian mining -engineer descended the river a few years ago, and four Italian traders a -year later floated down in rafts and canoes, losing almost all of their -cargo. For nearly two months they were marooned upon a sand-bar waiting -for the river to subside. At last they succeeded in reaching -Mulanquiato, an Indian settlement and plantation owned by Pereira, near -the entrance to the last canyon. Their attempted passage of the worst -stretch of rapids resulted in the loss of all their rubber cargo, the -work of a year. Among the half dozen others who have made the -journey--Indians and slave traders from down-river rubber posts--there -is no record of a single descent without the loss of at least one canoe. - -To reach the head of canoe navigation we made a two weeks' muleback -journey north of Cuzco through the steep-walled granite Canyon of -Torontoy, and to the sugar and cacao plantations of the middle Urubamba, -or Santa Ana Valley, where we outfitted. At Echarati, thirty miles -farther on, where the heat becomes more intense and the first patches of -real tropical forest begin, we were obliged to exchange our beasts for -ten fresh animals accustomed to forest work and its privations. Three -days later we pitched our tent on the river bank at Rosalina, the last -outpost of the valley settlements. As we dropped down the steep mountain -slope before striking the river flood plain, we passed two half-naked -Machiganga Indians perched on the limbs of a tree beside the trail, our -first sight of members of a tribe whose territory we had now entered. -Later in the day they crossed the river in a dugout, landed on the -sand-bar above us, and gathered brush for the nightly fire, around which -they lie wrapped in a single shirt woven from the fiber of the wild -cotton. - -[Illustration: FIG. 9--The upper entrance to the Pongo de Mainique, -where the Urubamba crosses the Front Range of the Andes in a splendid -gateway 4,000 feet deep. The river is broken by an almost continuous -line of rapids.] - -[Illustration: FIG. 10--The lower half of a two-thousand-foot cliff, -granite Canyon of Torontoy, Urubamba Valley. The wall is developed -almost entirely along joint planes. It is here that the Urubamba River -crosses the granite axis of the Cordillera Vilcapampa, the easternmost -system of the Andes of southern Peru. Compare also Figs. 144 and 145.] - -[Illustration: FIG. 11--A temporary shelter-hut on a sand-bar near the -great bend of the Urubamba (see map, Fig. 8). The Machiganga Indians use -these cane shelters during the fishing season, when the river is low.] - -[Illustration: FIG. 12--Thirty-foot canoe in a rapid above Pongo de -Mainique.] - -Rosalina is hardly more than a name on the map and a camp site on the -river bank. Some distance back from the left bank of the river is a -sugar plantation, whose owner lives in the cooler mountains, a day's -journey away; on the right bank is a small clearing planted to sugar -cane and yuca, and on the edge of it is a reed hut sheltering three -inhabitants, the total population of Rosalina. The owner asked our -destination, and to our reply that we should start in a few days for -Pongo de Mainique he offered two serious objections. No one thought of -arranging so difficult a journey in less than a month, for canoe and -Indians were difficult to find, and the river trip was dangerous. -Clearly, to start without the loss of precious time would require -unusual exertion. We immediately despatched an Indian messenger to the -owner of the small hacienda across the river while one of our peons -carried a second note to a priest of great influence among the forest -Indians, Padre Mendoza, then at his other home in the distant mountains. - -The answer of Señor Morales was his appearance in person to offer the -hospitality of his home and to assist us in securing canoe and oarsmen. -To our note the Padre, from his hill-top, sent a polite answer and the -offer of his large canoe if we would but guarantee its return. His -temporary illness prevented a visit to which we had looked forward with -great interest. - -The morning after our arrival I started out on foot in company with our -_arriero_ in search of the Machigangas, who fish and hunt along the -river bank during the dry season and retire to their hill camps when the -heavy rains begin. We soon left the well-beaten trail and, following a -faint woodland path, came to the river bank about a half day's journey -below Rosalina. There we found a canoe hidden in an overhanging arch of -vines, and crossing the river met an Indian family who gave us further -directions. Their vague signs were but dimly understood and we soon -found ourselves in the midst of a _carrizo_ (reed) swamp filled with -tall bamboo and cane and crossed by a network of interlacing streams. We -followed a faint path only to find ourselves climbing the adjacent -mountain slopes away from our destination. Once again in the swamp we -had literally to cut our way through the thick cane, wade the numberless -brooks, and follow wild animal trails until, late in the day, famished -and thirsty, we came upon a little clearing on a sand-bar, the hut of La -Sama, who knew the Machigangas and their villages. - -After our long day's work we had fish and yuca, and water to which had -been added a little raw cane sugar. Late at night La Sama returned from -a trip to the Indian villages down river. He brought with him a -half-dozen Machiganga Indians, boys and men, and around the camp fire -that night gave us a dramatic account of his former trip down river. At -one point he leaped to his feet, and with an imaginary pole shifted the -canoe in a swift rapid, turned it aside from imminent wreck, and -shouting at the top of his voice over the roar of the water finally -succeeded in evading what he had made seem certain death in a whirlpool. -We kept a fire going all night long for we slept upon the ground without -a covering, and, strange as it may appear, the cold seemed intense, -though the minimum thermometer registered 59° F. The next morning the -whole party of ten sunned themselves for nearly an hour until the flies -and heat once more drove them to shelter. - -Returning to camp next day by a different route was an experience of -great interest, because of the light it threw on hidden trails known -only to the Indian and his friends. Slave raiders in former years -devastated the native villages and forced the Indian to conceal his -special trails of refuge. At one point we traversed a cliff seventy-five -feet above the river, walking on a narrow ledge no wider than a man's -foot. At another point the dim trail apparently disappeared, but when we -had climbed hand over hand up the face of the cliff, by hanging vines -and tree roots, we came upon it again. Crossing the river in the canoe -we had used the day before, we shortened the return by wading the swift -Chirumbia waist-deep, and by crawling along a cliff face for nearly an -eighth of a mile. At the steepest point the river had so under-cut the -face that there was no trail at all, and we swung fully fifteen feet -from one ledge to another, on a hanging vine high above the river. - -After two days' delay we left Rosalina late in the afternoon of August -7. My party included several Machiganga Indians, La Sama, and Dr. W. G. -Erving, surgeon of the expedition. Mr. P. B. Lanius, Moscoso (the -_arriero_), and two peons were to take the pack train as far as possible -toward the rubber station at Pongo de Mainique where preparations were -to be made for our arrival. At the first rapid we learned the method of -our Indian boatmen. It was to run the heavy boat head on into shallow -water at one side of a rapid and in this way "brake" it down stream. -Heavily loaded with six men, 200 pounds of baggage, a dog, and supplies -of yuca and sugar cane our twenty-five foot dugout canoe was as rigid as -a steamer, and we dropped safely down rapid after rapid until long after -dark, and by the light of a glorious tropical moon we beached our craft -in front of La Sama's hut at the edge of the cane swamp. - -Here for five days we endured a most exasperating delay. La Sama had -promised Indian boatmen and now said none had yet been secured. Each day -Indians were about to arrive, but by nightfall the promise was broken -only to be repeated the following morning. To save our food supply--we -had taken but six days' provisions--we ate yuca soup and fish and some -parched corn, adding to this only a little from our limited stores. At -last we could wait no longer, even if the map had to be sacrificed to -the work of navigating the canoe. Our determination to leave stirred La -Sama to final action. He secured an assistant named Wilson and embarked -with us, planning to get Indians farther down river or make the journey -himself. - -On August 12, at 4.30 P.M., we entered upon the second stage of the -journey. As we shot down the first long rapid and rounded a wooded bend -the view down river opened up and gave us our first clear notion of the -region we had set out to explore. From mountain summits in the clouds -long trailing spurs descend to the river bank. In general the slopes are -smooth-contoured and forest-clad from summit to base; only in a few -places do high cliffs diversify the scenery. The river vista everywhere -includes a rapid and small patches of _playa_ or flood plain on the -inside of the river curves. Although a true canyon hems in the river at -two celebrated passes farther down, the upper part of the river flows -in a somewhat open valley of moderate relief, with here and there a -sentinel-like peak next the river. - -A light shower fell at sunset, a typical late-afternoon downpour so -characteristic of the tropics. We landed at a small encampment of -Machigangas, built a fire against the scarred trunk of a big palm, and -made up our beds in the open, covering them with our rubber ponchos. Our -Indian neighbors gave us yuca and corn, but their neighborliness went no -further, for when our boatmen attempted to sleep under their roofs they -drove them out and fastened as securely as possible the shaky door of -their hut. - -All our efforts to obtain Indians, both here and elsewhere, proved -fruitless. One excuse after another was overcome; they plainly coveted -the trinkets, knives, machetes, muskets, and ammunition that we offered -them; and they appeared to be friendly enough. Only after repeated -assurances of our friendship could we learn the real reason for their -refusal. Some of them were escaped rubber pickers that had been captured -by white raiders several years before, and for them a return to the -rubber country meant enslavement, heavy floggings, and separation from -their numerous wives. The hardships they had endured, their final -escape, the cruelty of the rubber men, and the difficult passage of the -rapids below were a set of circumstances that nothing in our list of -gifts could overcome. My first request a week before had so sharpened -their memory that one of them related the story of his wrongs, a recital -intensely dramatic to the whole circle of his listeners, including -myself. Though I did not understand the details of his story, his tones -and gesticulations were so effective that they held me as well as his -kinsmen of the woods spellbound for over an hour. - -It is appalling to what extent this great region has been depopulated by -the slave raiders and those arch enemies of the savage, smallpox and -malaria. At Rosalina, over sixty Indians died of malaria in one year; -and only twenty years ago seventy of them, the entire population of the -Pongo, were swept away by smallpox. For a week we passed former camps -near small abandoned clearings, once the home of little groups of -Machigangas. Even the summer shelter huts on the sand-bars, where the -Indians formerly gathered from their hill homes to fish, are now almost -entirely abandoned. Though our men carefully reconnoitered each one for -fear of ambush, the precaution was needless. Below the Coribeni the -Urubamba is a great silent valley. It is fitted by Nature to support -numerous villages, but its vast solitudes are unbroken except at night, -when a few families that live in the hills slip down to the river to -gather yuca and cane. - -By noon of the second day's journey we reached the head of the great -rapid at the mouth of the Sirialo. We had already run the long Coribeni -rapid, visited the Indian huts at the junction of the big Coribeni -tributary, exchanged our canoe for a larger and steadier one, and were -now to run one of the ugliest rapids of the upper river. The rapid is -formed by the gravel masses that the Sirialo brings down from the -distant Cordillera Vilcapampa. They trail along for at least a -half-mile, split the river into two main currents and nearly choke the -mouth of the tributary. For almost a mile above this great barrier the -main river is ponded and almost as quiet as a lake. - -We let our craft down this rapid by ropes, and in the last difficult -passage were so roughly handled by our almost unmanageable canoe as to -suffer from several bad accidents. All of the party were injured in one -way or another, while I suffered a fracture sprain of the left foot that -made painful work of the rest of the river trip. - -At two points below Rosalina the Urubamba is shut in by steep mountain -slopes and vertical cliffs. Canoe navigation below the Sirialo and -Coribeni rapids is no more hazardous than on the rapids of our northern -rivers, except at the two "pongos" or narrow passages. The first occurs -at the sharpest point of the abrupt curve shown on the map; the second -is the celebrated Pongo de Mainique. In these narrow passages in time of -high water there is no landing for long stretches. The bow paddler -stands well forward and tries for depth and current; the stern paddler -keeps the canoe steady in its course. When paddlers are in agreement -even a heavy canoe can be directed into the most favorable channels. -Our canoemen were always in disagreement, however, and as often as not -we shot down rapids at a speed of twenty miles an hour, broadside on, -with an occasional bump on projecting rocks or boulders whose warning -ordinary boatmen would not let go unheeded. - -The scenery at the great bend is unusually beautiful. The tropical -forest crowds the river bank, great cliffs rise sheer from the water's -edge, their faces overhung with a trailing drapery of vines, and in the -longer river vistas one may sometimes see the distant heights of the -Cordillera Vilcapampa. We shot the long succession of rapids in the -first canyon without mishap, and at night pitched our tent on the edge -of the river near the mouth of the Manugali. - -From the sharp peak opposite our camp we saw for the first time the -phenomenon of cloud-banners. A light breeze was blowing from the western -mountains and its vapor was condensed into clouds that floated down the -wind and dissolved, while they were constantly forming afresh at the -summit. In the night a thunderstorm arose and swept with a roar through -the vast forest above us. The solid canopy of the tropical forest fairly -resounded with the impact of the heavy raindrops. The next morning all -the brooks from the farther side of the river were in flood and the -river discolored. When we broke camp the last mist wraiths of the storm -were still trailing through the tree-tops and wrapped about the peak -opposite our camp, only parting now and then to give us delightful -glimpses of a forest-clad summit riding high above the clouds. - -The alternation of deeps and shallows at this point in the river and the -well-developed canyon meanders are among the most celebrated of their -kind in the world. Though shut in by high cliffs and bordered by -mountains the river exhibits a succession of curves so regular that one -might almost imagine the country a plain from the pattern of the -meanders. The succession of smooth curves for a long distance across -existing mountains points to a time when a lowland plain with moderate -slopes drained by strongly meandering rivers was developed here. Uplift -afforded a chance for renewed down-cutting on the part of all the -streams, and the incision of the meanders. The present meanders are, of -course, not the identical ones that were formed on the lowland plain; -they are rather their descendants. Though they still retain their -strongly curved quality, and in places have almost cut through the -narrow spurs between meander loops, they are not smooth like the -meanders of the Mississippi. Here and there are sharp irregular turns -that mar the symmetry of the larger curves. The alternating bands of -hard and soft rock have had a large part in making the course more -irregular. The meanders have responded to the rock structure. Though -regular in their broader features they are irregular and deformed in -detail. - -Deeps and shallows are known in every vigorous river, but it is seldom -that they are so prominently developed as in these great canyons. At one -point in the upper canyon the river has been broadened into a lake two -or three times the average width of the channel and with a scarcely -perceptible current; above and below the "laguna," as the boatmen call -it, are big rapids with beds so shallow that rocks project in many -places. In the Pongo de Mainique the river is at one place only fifty -feet wide, yet so deep that there is little current. It is on the banks -of the quiet stretches that the red forest deer grazes under leafy -arcades. Here, too, are the boa-constrictor trails several feet wide and -bare like a roadway. At night the great serpents come trailing down to -the river's edge, where the red deer and the wildcat, or so-called -"tiger," are their easy prey. - -It is in such quiet stretches that one also finds the vast colonies of -water skippers. They dance continuously in the sun with an incessant -motion from right to left and back again. Occasionally one dances about -in circles, then suddenly darts through the entire mass, though without -striking his equally erratic neighbors. An up-and-down motion still -further complicates the effect. It is positively bewildering to look -intently at the whirling multitude and try to follow their complicated -motions. Every slight breath of wind brings a shock to the organization -of the dance. For though they dance only in the sun, their favorite -places are the sunny spots in the shade near the bank, as beneath an -overhanging tree. When the wind shakes the foliage the mottled pattern -of shade and sunlight is confused, the dance slows down, and the dancers -become bewildered. In a storm they seek shelter in the jungle. The hot, -quiet, sunlit days bring out literally millions of these tiny creatures. - -One of the longest deeps in the whole Urubamba lies just above the Pongo -at Mulanquiato. We drifted down with a gentle current just after sunset. -Shrill whistles, like those of a steam launch, sounded from either bank, -the strange piercing notes of the lowland cicada, _cicada tibicen_. Long -decorated canoes, better than any we had yet seen, were drawn up in the -quiet coves. Soon we came upon the first settlement. The owner, Señor -Pereira, has gathered about him a group of Machigangas, and by marrying -into the tribe has attained a position of great influence among the -Indians. Upon our arrival a gun was fired to announce to his people that -strangers had come, upon which the Machigangas strolled along in twos -and threes from their huts, helped us ashore with the baggage, and -prepared the evening meal. Here we sat down with five Italians, who had -ventured into the rubber fields with golden ideas as to profits. After -having lost the larger part of their merchandise, chiefly cinchona, in -the rapids the year before, they had established themselves here with -the idea of picking rubber. Without capital, they followed the ways of -the itinerant rubber picker and had gathered "caucho," the poorer of the -two kinds of rubber. No capital is required; the picker simply cuts down -the likeliest trees, gathers the coagulated sap, and floats it -down-stream to market. After a year of this life they had grown restless -and were venturing on other schemes for the great down-river rubber -country. - -[Illustration: FIG. 13--Composition of tropical vegetation in the rain -forest above Pongo de Mainique, elevation 2,500 feet (760 m.). Scores of -species occur within the limits of a single photograph.] - -[Illustration: FIG. 14--The mule trail in the rain forest between -Rosalina and Pongo de Mainique. Each pool is from one and a half to two -feet deep. Even in the dry season these holes are full of water, for the -sunlight penetrates the foliage at a few places only.] - -[Illustration: FIG. 15--Topography and vegetation from the Tocate pass, -7,100 feet (2,164 m.), between Rosalina and Pongo de Mainique. See Fig. -53a. This is in the zone of maximum rainfall. The cumulo-nimbus clouds -are typical and change to nimbus in the early afternoon.] - -[Illustration: FIG. 16--The Expedition's thirty-foot canoe at the mouth -of the Timpia below Pongo de Mainique.] - -A few weeks later, on returning through the forest, we met their -carriers with a few small bundles, the only part of their cargo they had -saved from the river. Without a canoe or the means to buy one they had -built rafts, which were quickly torn to pieces in the rapids. We, too, -should have said "_pobres Italianos_" if their venture had not been -plainly foolish. The rubber territory is difficult enough for men -with capital; for men without capital it is impossible. Such men either -become affiliated with organized companies or get out of the region when -they can. A few, made desperate by risks and losses, cheat and steal -their way to rubber. Two years before our trip an Italian had murdered -two Frenchmen just below the Pongo and stolen their rubber cargo, -whereupon he was shot by Machigangas under the leadership of Domingo, -the chief who was with us on a journey from Pongo de Mainique to the -mouth of the Timpia. Afterward they brought his skull to the top of a -pass along the forest trail and set it up on a cliff at the very edge of -Machiganga-land as a warning to others of his kind. - -At Mulanquiato we secured five Machigangas and a boy interpreter, and on -August 17 made the last and most difficult portion of our journey. We -found these Indians much more skilful than our earlier boatmen. -Well-trained, alert, powerful, and with excellent team-play, they swept -the canoe into this or that thread of the current, and took one after -another of the rapids with the greatest confidence. No sooner had we -passed the Sintulini rapids, fully a mile long, than we reached the -mouth of the Pomareni. This swift tributary comes in almost at right -angles to the main river and gives rise to a confusing mass of standing -waves and conflicting currents rendered still more difficult by the -whirlpool just below the junction. So swift is the circling current of -the maëlstrom that the water is hollowed out like a great bowl, a really -formidable point and one of our most dangerous passages; a little too -far to the right and we should be thrown over against the cliff-face; a -little too far to the left and we should be caught in the whirlpool. -Once in the swift current the canoe became as helpless as a chip. It was -turned this way and that, each turn heading it apparently straight for -destruction. But the Indians had judged their position well, and though -we seemed each moment in a worse predicament, we at last skimmed the -edge of the whirlpool and brought our canoe to shore just beyond its -rim. - -A little farther on we came to the narrow gateway of the Pongo, where -the entire volume of the river flows between cliffs at one point no -more than fifty feet apart. Here are concentrated the worst rapids of -the lower Urubamba. For nearly fifteen miles the river is an unbroken -succession of rapids, and once within its walls the Pongo offers small -chance of escape. At some points we were fortunate enough to secure a -foothold along the edge of the river and to let our canoe down by ropes. -At others we were obliged to take chances with the current, though the -great depth of water in most of the Pongo rapids makes them really less -formidable in some respects than the shallow rapids up stream. The chief -danger here lies in the rotary motion of the water at the sharpest -bends. The effect at some places is extraordinary. A floating object is -carried across stream like a feather and driven at express-train speed -against a solid cliff. In trying to avoid one of these cross-currents -our canoe became turned midstream, we were thrown this way and that, and -at last shot through three standing waves that half filled the canoe. - -Below the worst rapids the Pongo exhibits a swift succession of natural -wonders. Fern-clad cliffs border it, a bush resembling the juniper -reaches its dainty finger-like stems far out over the river, and the -banks are heavily clad with mosses. The great woods, silent, -impenetrable, mantle the high slopes and stretch up to the limits of -vision. Cascades tumble from the cliff summits or go rippling down the -long inclines of the slate beds set almost on edge. Finally appear the -white pinnacles of limestone that hem in the narrow lower entrance or -outlet of the Pongo. Beyond this passage one suddenly comes out upon the -edge of a rolling forest-clad region, the rubber territory, the country -of the great woods. Here the Andean realm ends and Amazonia begins. - -From the summits of the white cliffs 4,000 feet above the river we were -in a few days to have one of the most extensive views in South America. -The break between the Andean Cordillera and the hill-dotted plains of -the lower Urubamba valley is almost as sharp as a shoreline. The rolling -plains are covered with leagues upon leagues of dense, shadowy, -fever-haunted jungle. The great river winds through in a series of -splendid meanders, and with so broad a channel as to make it visible -almost to the horizon. Down river from our lookout one can reach ocean -steamers at Iquitos with less than two weeks of travel. It is three -weeks to the Pacific _via_ Cuzco and more than a month if one takes the -route across the high bleak lava-covered country which we were soon to -cross on our way to the coast at Camaná. - - - - -CHAPTER III - -THE RUBBER FORESTS - - -The white limestone cliffs at Pongo de Mainique are a boundary between -two great geographic provinces (Fig. 17). Down valley are the vast river -plains, drained by broad meandering rivers; up valley are the rugged -spurs of the eastern Andes and their encanyoned streams (Fig. 18). There -are outliers of the Andes still farther toward the northeast where hangs -the inevitable haze of the tropical horizon, but the country beyond them -differs in no important respect from that immediately below the Pongo. - -[Illustration: FIG. 17--Regional diagram of the Eastern Andes (here the -Cordillera Vilcapampa) and the adjacent tropical plains. For an -explanation of the method of construction and the symbolism of the -diagram see p. 51.] - -The foot-path to the summit of the cliffs is too narrow and steep for -even the most agile mules. It is simply impassable for animals without -hands. In places the packs are lowered by ropes over steep ledges and -men must scramble down from one projecting root or swinging vine to -another. In the breathless jungle it is a wearing task to pack in all -supplies for the station below the Pongo and to carry out the season's -rubber. Recently however the ancient track has been replaced by a road -that was cut with great labor, and by much blasting, across the mountain -barrier, and at last mule transport has taken the place of the Indian. - -[Illustration: FIG. 18--Index map for the nine regional diagrams in the -pages following. A represents Fig. 17; B, 42; C, 36; D, 32; E, 34; F, -25; G, 26; and H, 65.] - -In the dry season it is a fair and delightful country--that on the -border of the mountains. In the wet season the traveler is either -actually marooned or he must slosh through rivers of mud and water that -deluge the trails and break the hearts of his beasts (Fig. 14). Here and -there a large shallow-rooted tree has come crashing down across the -trail and with its four feet of circumference and ten feet of plank -buttress it is as difficult to move as a house. A new trail must be cut -around it. A little farther on, where the valley wall steepens and one -may look down a thousand feet of slope to the bed of a mountain torrent, -a patch of trail has become soaked with water and the mules pick their -way, trembling, across it. Two days from Yavero one of our mules went -over the trail, and though she was finally recovered she died of her -injuries the following night. After a month's work in the forest a mule -must run free for two months to recover. The packers count on losing one -beast out of five for every journey into the forest. It is not solely a -matter of work, though this is terrific; it is quite largely a matter of -forage. In spite of its profusion of life (Fig. 13) and its really vast -wealth of species, the tropical forest is all but barren of grass. Sugar -cane is a fair substitute, but there are only a few cultivated spots. -The more tender leaves of the trees, the young shoots of cane in the -_carrizo_ swamps, and the grass-like foliage of the low bamboo are the -chief substitutes for pasture. But they lead to various disorders, -besides requiring considerable labor on the part of the dejected peons -who must gather them after a day's heavy work with the packs. - -Overcoming these enormous difficulties is expensive and some one must -pay the bill. As is usual in a pioneer region, the native laborer pays a -large part of it in unrequited toil; the rest is paid by the rubber -consumer. For this is one of the cases where a direct road connects the -civilized consumer and the barbarous producer. What a story it could -tell if a ball of smoke-cured rubber on a New York dock were endowed -with speech--of the wet jungle path, of enslaved peons, of vile abuses -by immoral agents, of all the toil and sickness that make the tropical -lowland a reproach! - -[Illustration: FIG. 19--Moss-draped trees in the rain forest near Abra -Tocate between Rosalina and Pongo de Mainique.] - -[Illustration: FIG. 20--Yavero, a rubber station on the Yavero -(Paucartambo) River, a tributary of the Urubamba. Elevation 1,600 feet -(490 m.).] - -In the United States the specter of slavery haunted the national -conscience almost from the beginning of national life, and the ghost was -laid only at the cost of one of the bloodiest wars in history. In other -countries, as in sugar-producing Brazil, the freeing of the slaves meant -not a war but the verge of financial ruin besides a fundamental -change in the social order and problems as complex and wearisome as any -that war can bring. Everywhere abolition was secured at frightful cost. - -[Illustration: FIG. 21--Clearing in the tropical forest between Rosalina -and Pabellon. This represents the border region where the -forest-dwelling Machiganga Indians and the mountain Indians meet. The -clearings are occupied by Machigangas whose chief crops are yuca and -corn; in the extreme upper left-hand corner are grassy slopes occupied -by Quechua herdsmen and farmers who grow potatoes and corn.] - -The spirit that upheld the new founders of the western republics in -driving out slavery was admirable, but as much cannot be said of their -work of reconstruction. We like to pass over those dark days in our own -history. In South America there has lingered from the old slave-holding -days down to the present, a labor system more insidious than slavery, -yet no less revolting in its details, and infinitely more difficult to -stamp out. It is called peonage; it should be called slavery. In -Bolivia, Peru, and Brazil it flourishes now as it ever did in the -fruitful soil of the interior provinces where law and order are bywords -and where the scarcity of workmen will long impel men to enslave labor -when they cannot employ it. Peonage _is_ slavery, though as in all slave -systems there are many forms under which the system is worked out. We -commonly think that the typical slave is one who is made to work hard, -given but little food, and at the slightest provocation is tied to a -post and brutally whipped. This is indeed the fate of many slaves or -"peons" so-called, in the Amazon forests; but it is no more the rule -than it was in the South before the war, for a peon is a valuable piece -of property and if a slave raider travel five hundred miles through -forest and jungle-swamp to capture an Indian you may depend upon it that -he will not beat him to death merely for the fun of it. - -That unjust and frightfully cruel floggings are inflicted at times and -in some places is of course a result of the lack of official restraint -that drunken owners far from the arm of the law sometimes enjoy. When a -man obtains a rubber concession from the government he buys a kingdom. -Many of the rubber territories are so remote from the cities that -officials can with great difficulty be secured to stay at the customs -ports. High salaries must be paid, heavy taxes collected, and grafting -of the most flagrant kind winked at. Often the concessionaire himself is -chief magistrate of his kingdom by law. Under such a system, remote from -all civilizing influences, the rubber producer himself oftentimes a -lawless border character or a downright criminal, no system of -government would be adequate, least of all one like peonage that permits -or ignores flagrant wrongs because it is so expensive to enforce -justice. - -The peonage system continues by reason of that extraordinary difficulty -in the development of the tropical lowland of South America--the lack of -a labor supply. The population of Amazonia now numbers less than one -person to the square mile. The people are distributed in small groups of -a dozen to twenty each in scattered villages along the river banks or in -concealed clearings reached by trails known only to the Indians. Nearly -all of them still live in the same primitive state in which they lived -at the time of the Discovery. In the Urubamba region a single cotton -shirt is worn by the married men and women, while the girls and boys in -many cases go entirely naked except for a loincloth or a necklace of -nuts or monkeys' teeth (Fig. 23). A cane hut with a thatch to keep out -the heavy rains is their shelter and their food is the yuca, sugar cane, -Indian corn, bananas of many kinds, and fish. A patch of yuca once -planted will need but the most trifling attention for years. The small -spider monkey is their greatest delicacy and to procure it they will -often abandon every other project and return at their own sweet and -belated will. - -[Illustration: FIG. 22--Trading with Machiganga Indians in a reed swamp -at Santao Anato, Urubamba Valley, before Rosalina. Just outside the -picture on the right is a platform on which corn is stored for -protection against rodents and mildew. On the left is the corner of a -grass-thatched cane hut.] - -In the midst of this natural life of the forest-dwelling Indian appears -the rubber man, who, to gather rubber, must have rubber "pickers." If he -lives on the edge of the great Andean Cordillera, laborers may be -secured from some of the lower valleys, but they must be paid well for -even a temporary stay in the hot and unhealthful lowlands. Farther out -in the great forest country the plateau Indians will not go and only the -scattered tribes remain from which to recruit laborers. For the -nature-life of the Indian what has the rubber gatherer to offer? Money? -The Indian uses it for ornament only. When I once tried with money to -pay an Indian for a week's services he refused it. In exchange for his -severe labor he wanted nothing more than a fish-hook and a ring, the two -costing not more than a penny apiece! When his love for ornament has -once been gratified the Indian ceases to work. His food and shelter -and clothing are of the most primitive kind, but they are the best in -the world for him because they are the only kind he has known. So where -money and finery fail the lash comes in. The rubber man says that the -Indian is lazy and must be made to work; that there is a great deal of -work to be done and the Indian is the only laborer who can be found; -that if rubber and chocolate are produced the Indian must be made to -produce them; and that if he will not produce them for pay he must be -enslaved. - -[Illustration: FIG. 23--Ornaments and fabrics of the Machiganga Indians -at Yavero. The nuts are made up into strings, pendants, and heavy -necklaces. To the left of the center is one that contains feathers and -four drumsticks of a bird about the size of a small wild -turkey--probably the so-called turkey inhabiting the eastern mountain -valleys and the adjacent border of the plains, and hunted as an -important source of food. The cord in the upper right-hand corner is -used most commonly for heel supports in climbing trees. The openwork -sack is convenient for carrying game, fish, and fruit; the finely woven -sacks are used for carrying red ochre for ornamenting or daubing faces -and arms. They are also used for carrying corn, trinkets, and game.] - -It is a law of the rubber country that when an Indian falls into debt to -a white man he must work for the latter until the debt is discharged. If -he runs away before the debt is canceled or if he refuses to work or -does too little work he may be flogged. Under special conditions such -laws are wise. In the hands of the rubber men they are the basis of -slavery. For, once the rubber interests begin to suffer, the promoters -look around for a chance to capture free Indians. An expedition is -fitted out that spends weeks exploring this river or that in getting on -the track of unattached Indians. When a settlement is found the men are -enslaved and taken long distances from home finally to reach a rubber -property. There they are given a corner of a hut to sleep in, a few -cheap clothes, a rubber-picking outfit, and a name. In return for these -articles the unwilling Indian is charged any fanciful price that comes -into the mind of his "owner," and he must thereupon work at a per diem -wage also fixed by the owner. Since his obligations increase with time, -the Indian may die over two thousand dollars in debt! - -Peonage has left frightful scars upon the country. In some places the -Indians are fugitives, cultivating little farms in secreted places but -visiting them only at night or after carefully reconnoitering the spot. -They change their camps frequently and make their way from place to -place by secret trails, now spending a night or two under the shelter of -a few palm leaves on a sandbar, again concealing themselves in almost -impenetrable jungle. If the hunter sometimes discovers a beaten track he -follows it only to find it ending on a cliff face or on the edge of a -lagoon where concealment is perfect. There are tribes that shoot the -white man at sight and regard him as their bitterest enemy. Experience -has led them to believe that only a dead white is a good white, -reversing our saying about the North American Indian; and that even when -he comes among them on peaceful errands he is likely to leave behind him -a trail of syphilis and other venereal diseases scarcely less deadly -than his bullets. - -However, the peonage system is not hideous everywhere and in all its -aspects. There are white owners who realize that in the long run the -friendship of the Indians is an asset far greater than unwilling service -and deadly hatred. Some of them have indeed intermarried with the -Indians and live among them in a state but little above savagery. In the -Mamoré country are a few owners of original princely concessions who -have grown enormously wealthy and yet who continue to live a primitive -life among their scores of illegitimate descendants. The Indians look -upon them as benefactors, as indeed many of them are, defending the -Indians from ill treatment by other whites, giving them clothing and -ornaments, and exacting from them only a moderate amount of labor. In -some cases indeed the whites have gained more than simple gratitude for -their humane treatment of the Indians, some of whom serve their masters -with real devotion. - -When the "rubber barons" wish to discourage investigation of their -system they invite the traveler to leave and he is given a canoe and -oarsmen with which to make his way out of the district. Refusal to -accept an offer of canoes and men is a declaration of war. An agent of -one of the London companies accepted such a challenge and was promptly -told that he would not leave the territory alive. The threat would have -held true in the case of a less skilful man. Though Indians slept in the -canoes to prevent their seizure, he slipped past the guards in the -night, swam to the opposite shore, and there secured a canoe within -which he made a difficult journey down river to the nearest post where -food and an outfit could be secured. - -A few companies operating on or near the border of the Cordillera have -adopted a normal labor system, dependent chiefly upon people from the -plateau and upon the thoroughly willing assistance of well-paid forest -Indians. The Compañia Gomera de Mainique at Puerto Mainique just below -the Pongo is one of these and its development of the region without -violation of native rights is in the highest degree praiseworthy. In -fact the whole conduct of this company is interesting to a geographer, -as it reflects at every point the physical nature of the country. - -The government is eager to secure foreign capital, but in eastern Peru -can offer practically nothing more than virgin wealth, that is, land and -the natural resources of the land. There are no roads, virtually no -trails, no telegraph lines, and in most cases no labor. Since the old -Spanish grants ran at right angles to the river so as to give the owners -a cross-section of varied resources, the up-river plantations do not -extend down into the rubber country. Hence the more heavily forested -lower valleys and plains are the property of the state. A man can buy a -piece of land down there, but from any tract within ordinary means only -a primitive living can be obtained. The pioneers therefore are the -rubber men who produce a precious substance that can stand the enormous -tax on production and transportation. They do not want the land--only -the exclusive right to tap the rubber trees upon it. Thus there has -arisen the concession plan whereby a large tract is obtained under -conditions of money payment or of improvements that will attract -settlers or of a tax on the export. - -The "caucho" or poorer rubber of the Urubamba Valley begins at 3,000 -feet (915 m.) and the "hevea" or better class is a lower-valley and -plains product. The rubber trees thereabouts produce 60 grams (2 ozs.) -of dry rubber each week for eight months. After yielding rubber for this -length of time a tree is allowed to rest four or five years. "Caucho" is -produced from trees that are cut down and ringed with machetes, but it -is from fifty to sixty cents cheaper owing to the impurities that get -into it. The wood, not the nut, of the _Palma carmona_ is used for -smoking or "curing" the rubber. The government had long been urged to -build a road into the region in place of the miserable track--absolutely -impassable in the wet season--that heretofore constituted the sole -means of exit. About ten years ago Señor Robledo at last built a -government trail from Rosalina to Yavero about 100 miles long. While it -is a wretched trail it is better than the old one, for it is more direct -and it is better drained. In the wet season parts of it are turned into -rivers and lakes, but it is probably the best that could be done with -the small grant of twenty thousand dollars. - -With at least an improvement in the trail it became possible for a -rubber company to induce _cargadores_ or packers to transport -merchandise and rubber and to have a fair chance of success. Whereupon a -rubber company was organized which obtained a concession of 28,000 -hectares (69,188 acres) of land on condition that the company finish a -road one and one-half meters wide to the Pongo, connecting with the road -which the government had extended to Yavero. The land given in payment -was not continuous but was selected in lots by the company in such a way -as to secure the best rubber trees over an area several times the size -of the concession. The road was finished by William Tell after four -years' work at a cost of about seventy-five thousand dollars. The last -part of it was blasted out of slate and limestone and in 1912 the first -pack train entered Puerto Mainique. - -The first rubber was taken out in November, 1910, and productive -possibilities proved by the collection of 9,000 kilos (19,841 pounds) in -eight months. - -If a main road were the chief problem of the rubber company the business -would soon be on a paying basis, but for every mile of road there must -be cut several miles of narrow trail (Fig. 14), as the rubber trees grow -scattered about--a clump of a half dozen here and five hundred feet -farther on another clump and only scattered individuals between. -Furthermore, about twenty-five years ago rubber men from the Ucayali -came up here in launches and canoes and cut down large numbers of trees -within reach of the water courses and by ringing the trunks every few -feet with machetes "bled" them rapidly and thus covered a large -territory in a short time, and made huge sums of money when the price of -rubber was high. Only a few of the small trees that were left are now -mature. These, the mature trees that were overlooked, and the virgin -stands farther from the rivers are the present sources of rubber. - -In addition to the trails small cabins must be built to shelter the -hired laborers from the plateau, many of whom bring along their women -folk to cook for them. The combined expense to a company of these -necessary improvements before production can begin is exceedingly heavy. -There is only one alternative for the prospective exploiter: to become a -vagrant rubber gatherer. With tents, guns, machetes, cloth, baubles for -trading, tinned food for emergencies, and with pockets full of English -gold parties have started out to seek fortunes in the rubber forests. If -the friendship of a party of Indians can be secured by adequate gifts -large amounts of rubber can be gathered in a short time, for the Indians -know where the rubber trees grow. On the other hand, many fortunes have -been lost in the rubber country. Some of the tribes have been badly -treated by other adventurers and attack the newcomers from ambush or -gather rubber for a while only to overturn the canoe in a rapid and let -the river relieve them of selfish friends. - -The Compañia Gomera de Mainique started out by securing the good-will of -the forest Indians, the Machigangas. They come and go in friendly visits -to the port at Yavero. If one of them is sick he can secure free -medicine from the agent. If he wishes goods on credit he has only to ask -for them, for the agent knows that the Indian's sense of fairness will -bring him back to work for the company. Without previous notice a group -of Indians appears: - -"We owe," they announce. - -"Good," says the agent, "build me a house." - -They select the trees. Before they cut them down they address them -solemnly. The trees must not hold their destruction against the Indians -and they must not try to resist the sharp machetes. Then the Indians set -to work. They fell a tree, bind it with light ropes woven from the wild -cotton, and haul it to its place. That is all for the day. They play in -the sun, do a little hunting, or look over the agent's house, touching -everything, talking little, exclaiming much. They dip their wet fingers -in the sugar bowl and taste, turn salt out upon their hands, hold -colored solutions from the medicine chest up to the light, and pull out -and push in the corks of the bottles. At the end of a month or two the -house is done. Then they gather their women and babies together and say: - -"Now we go," without asking if the work corresponds with the cost of the -articles they had bought. Their judgment is good however. Their work is -almost always more valuable than the articles. Then they shake hands all -around. - -"We will come again," they say, and in a moment have disappeared in the -jungle that overhangs the trail. - -With such labor the Compañia Gomera de Mainique can do something, but it -is not much. The regular seasonal tasks of road-building and -rubber-picking must be done by imported labor. This is secured chiefly -at Abancay, where live groups of plateau Indians that have become -accustomed to the warm climate of the Abancay basin. They are employed -for eight or ten months at an average rate of fifty cents gold per day, -and receive in addition only the simplest articles of food. - -At the end of the season the gang leaders are paid a _gratificación_, or -bonus, the size of which depends upon the amount of rubber collected, -and this in turn depends upon the size of the gang and the degree of -willingness to work. In the books of the company I saw a record of -_gratificaciónes_ running as high as $600 in gold for a season's work. - -Some of the laborers become sick and are cared for by the agent until -they recover or can be sent back to their homes. Most of them have fever -before they return. - -The rubber costs the company two _soles_ ($1.00) produced at Yavero. The -two weeks' transportation to Cuzco costs three and a half soles ($1.75) -per twenty-five pounds. The exported rubber, known to the trade as -Mollendo rubber, in contrast to the finer "Pará" rubber from the lower -Amazon, is shipped to Hamburg. The cost for transportation from port to -port is $24.00 per English ton (1,016 kilos). There is a Peruvian tax of -8 per cent of the net value in Europe, and a territorial tax of two -soles ($1.00) per hundred pounds. All supplies except the few vegetables -grown on the spot cost tremendously. Even dynamite, hoes, clothing, -rice--to mention only a few necessities--must pay the heavy cost of -transportation after imposts, railroad and ocean freight, storage and -agents' percentages are added. The effect of a disturbed market is -extreme. When, in 1911, the price of rubber fell to $1.50 a kilo at -Hamburg the company ceased exporting. When it dropped still lower in -1912 production also stopped, and it is still doubtful, in view of the -growing competition of the East-Indian plantations with their cheap -labor, whether operations will ever be resumed. Within three years no -less than a dozen large companies in eastern Peru and Bolivia have -ceased operations. In one concession on the Madre de Dios the withdrawal -of the agents and laborers from the posts turned at last into flight, as -the forest Indians, on learning the company's policy, rapidly ascended -the river in force, committing numerous depredations. The great war has -also added to the difficulties of production. - -Facts like these are vital in the consideration of the future of the -Amazon basin and especially its habitability. It was the dream of -Humboldt that great cities should arise in the midst of the tropical -forests of the Amazon and that the whole lowland plain of that river -basin should become the home of happy millions. Humboldt's vision may -have been correct, though a hundred years have brought us but little -nearer its realization. Now, as in the past four centuries, man finds -his hands too feeble to control the great elemental forces which have -shaped history. The most he can hope for in the next hundred years at -least is the ability to dodge Nature a little more successfully, and -here and there by studies in tropical hygiene and medicine, by the -substitution of water-power for human energy, to carry a few of the -outposts and prepare the way for a final assault in the war against the -hard conditions of climate and relief. We hear of the Madeira-Mamoré -railroad, 200 miles long, in the heart of a tropical forest and of the -commercial revolution it will bring. Do we realize that the forest which -overhangs the rails is as big as the whole plain between the Rockies -and the Appalachians, and that the proposed line would extend only as -far as from St. Louis to Kansas City, or from Galveston to New Orleans? - -Even if twenty whites were eager to go where now there is but one -reluctant pioneer, we should still have but a halting development on -account of the scarcity of labor. When, three hundred years ago, the -Isthmus of Panama stood in his way, Gomara wrote to his king: "There are -mountains, but there are also hands," as if men could be conjured up -from the tropical jungle. From that day to this the scarcity of labor -has been the chief difficulty in the lowland regions of tropical South -America. Even when medicine shall have been advanced to the point where -residence in the tropics can be made safe, the Amazon basin will lack an -adequate supply of workmen. Where Humboldt saw thriving cities, the -population is still less than one to the square mile in an area as large -as fifteen of our Mississippi Valley states. We hear much about a rich -soil and little about intolerable insects; the climate favors a good -growth of vegetation, but a man can starve in a tropical forest as -easily as in a desert; certain tributaries of the Negro are bordered by -rich rubber forests, yet not a single Indian hut may be found along -their banks. Will men of the white race dig up the rank vegetation, -sleep in grass hammocks, live in the hot and humid air, or will they -stay in the cooler regions of the north and south? Will they rear -children in the temperate zones, or bury them in the tropics? - -What Gorgas did for Panama was done for intelligent people. Can it be -duplicated in the case of ignorant and stupid laborers? Shall the white -man with wits fight it out with Nature in a tropical forest, or fight it -out with his equals under better skies? - -The tropics must be won by strong hands of the lowlier classes who are -ignorant or careless of hygiene, and not by the khaki-clad robust young -men like those who work at Panama. Tropical medicine can do something -for these folk, but it cannot do much. And we cannot surround every -laborer's cottage with expensive screens, oiled ditches, and well-kept -lawns. There is a practical optimism and a sentimental optimism. The one -is based on facts; the other on assumptions. It is pleasant to think -that the tropical forest may be conquered. It is nonsense to say that we -are now conquering it in any comprehensive and permanent way. That sort -of conquest is still a dream, as when Humboldt wrote over a hundred -years ago. - - - - -CHAPTER IV - -THE FOREST INDIANS - - -The people of a tropical forest live under conditions not unlike those -of the desert. The Sahara contains 2,000,000 persons within its borders, -a density of one-half to the square mile. This is almost precisely the -density of population of a tract of equivalent size in the lowland -forests of South America. Like the oases groups in the desert of aridity -are the scattered groups along the river margins of the forest. The -desert trails run from spring to spring or along a valley floor where -there is seepage or an intermittent stream; the rivers are the highways -of the forest, the flowing roads, and away from them one is lost in as -true a sense as one may be lost in the desert. - -A man may easily starve in the tropical forest. Before starting on even -a short journey of two or three days a forest Indian stocks his canoe -with sugar cane and yuca and a little parched corn. He knows the -settlements as well as his desert brother knows the springs. The Pahute -Indian of Utah lives in the irrigated valleys and makes annual -excursions across the desert to the distant mountains to gather the -seeds of the nut pine. The Machiganga lives in the hills above the -Urubamba and annually comes down through the forest to the river to fish -during the dry season. - -The Machigangas are one of the important tribes of the Amazon basin. -Though they are dispersed to some extent upon the plains their chief -groups are scattered through the heads of a large number of valleys near -the eastern border of the Andes. Chief among the valleys they occupy are -the Pilcopata, Tono, Piñi-piñi, Yavero, Yuyato, Shirineiri, Ticumpinea, -Timpia, and Camisea (Fig. 203). In their distribution, in their -relations with each other, in their manner of life, and to some extent -in their personal traits, they display characteristics strikingly like -those seen in desert peoples. Though the forest that surrounds them -suggests plenty and the rivers the possibility of free movement with -easy intercourse, the struggle of life, as in the desert, is against -useless things. Travel in the desert is a conflict with heat and -aridity; but travel in the tropic forest is a struggle against space, -heat, and a superabundant and all but useless vegetation. - -The Machigangas are one of the subtribes of the Campas Indians, one of -the most numerous groups in the Amazon Valley. It is estimated that -there are in all about 14,000 to 16,000 of them. Each subtribe numbers -from one to four thousand, and the territory they occupy extends from -the limits of the last plantations--for example, Rosalina in the -Urubamba Valley--downstream beyond the edge of the plains. Among them -three subtribes are still hostile to the whites: the Cashibos, the -Chonta Campas, and the Campas Bravos. - -In certain cases the Cashibos are said to be anthropophagous, in the -belief that they will assume the strength and intellect of those they -eat. This group is also continuously at war with its neighbors, goes -naked, uses stone hatchets, as in ages past, because of its isolation -and unfriendliness, and defends the entrances to the tribal huts with -dart and traps. The Cashibos are diminishing in numbers and are now -scattered through the valley of the Gran Pajonal, the left bank of the -Pachitea, and the Pampa del Sacramento.[2] - -The friendliest tribes live in the higher valley heads, where they have -constant communication with the whites. The use of the bow and arrow has -not, however, been discontinued among them, in spite of the wide -introduction of the old-fashioned muzzle-loading shotgun, which they -prize much more highly than the latest rifle or breech-loading shotgun -because of its simplicity and cheapness. Accidents are frequent among -them owing to the careless use of fire-arms. On our last day's journey -on the Urubamba above the mouth of the Timpia one of our Indian boys -dropped his canoe pole on the hammer of a loaded shotgun, and not only -shot his own fingers to pieces, but gravely wounded his father (Fig. 2). -In spite of his suffering the old chief directed our work at the canoe -and even was able to tell us the location of the most favorable channel. -Though the night that followed was as black as ink, with even the stars -obscured by a rising storm, his directions never failed. We poled our -way up five long rapids without special difficulties, now working into -the lee of a rock whose location he knew within a few yards, now -paddling furiously across the channel to catch the upstream current of -an eddy. - -The principal groups of Machigangas live in the middle Urubamba and its -tributaries, the Yavero, Yuyato, Shirineiri, Ticumpinea, Timpia, -Pachitea, and others. There is a marked difference in the use of the -land and the mode of life among the different groups of this subtribe. -Those who live in the lower plains and river "playas," as the patches of -flood plain are called, have a single permanent dwelling and alternately -fish and hunt. Those that live on hill farms have temporary reed huts on -the nearest sandbars and spend the best months of the dry season--April -to October--in fishing and drying fish to be carried to their mountain -homes (Fig. 21). Some families even duplicate _chacras_ or farms at the -river bank and grow yuca and sugar cane. In latter years smallpox, -malaria, and the rubber hunters have destroyed many of the river -villages and driven the Indians to permanent residence in the hills or, -where raids occur, along secret trails to hidden camps. - -Their system of agriculture is strikingly adapted to some important -features of tropical soil. The thin hillside soils of the region are but -poorly stocked with humus, even in their virgin condition. Fallen trees -and foliage decay so quickly that the layer of forest mold is -exceedingly thin and the little that is incorporated in the soil is -confined to a shallow surface layer. To meet these special conditions -the Indian makes new clearings by girdling and burning the trees. When -the soil becomes worn out and the crops diminish, the old clearing is -abandoned and allowed to revert to natural growth and a new farm is -planted to corn and yuca. The population is so scattered and thin that -the land assignment system current among the plateau Indians is not -practised among the Machigangas. Several families commonly live together -and may be separated from their nearest neighbors by many miles of -forested mountains. The land is free for all, and, though some heavy -labor is necessary to clear it, once a small patch is cleared it is easy -to extend the tract by limited annual cuttings. Local tracts of -naturally unforested land are rarely planted, chiefly because the -absence of shade has allowed the sun to burn out the limited humus -supply and to prevent more from accumulating. The best soil of the -mountain slopes is found where there is the heaviest growth of timber, -the deepest shade, the most humus, and good natural drainage. It is the -same on the playas along the river; the recent additions to the flood -plain are easy to cultivate, but they lack humus and a fine matrix which -retains moisture and prevents drought or at least physiologic dryness. -Here, too, the timbered areas or the cane swamps are always selected for -planting. - -The traditions of the Machigangas go back to the time of the Inca -conquest, when the forest Indians, the "Antis," were subjugated and -compelled to pay tribute.[3] When the Inca family itself fled from Cuzco -after the Spanish Conquest and sought refuge in the wilderness it was to -the Machiganga country that they came by way of the Vilcabamba and -Pampaconas Valleys. Afterward came the Spaniards and though they did not -exercise governmental authority over the forest Indians they had close -relations with them. Land grants were made to white pioneers for special -services or through sale and with the land often went the right to -exploit the people on it. Some of the concessions were owned by people -who for generations knew nothing save by hearsay of the Indians who -dwelt in the great forests of the valleys. In later years they have been -exploring their lands and establishing so-called relations whereby the -savage "buys" a dollar's worth of powder or knives for whatever number -of dollars' worth of rubber the owner may care to extract from him. - -The forest Indian is still master of his lands throughout most of the -Machiganga country. He is cruelly enslaved at the rubber posts, held by -the loose bonds of a desultory trade at others, and in a few places, as -at Pongo do Mainique, gives service for both love and profit, but in -many places it is impossible to establish control or influence. The -lowland Indian never falls into the abject condition of his Quechua -brother on the plateau. He is self-reliant, proud, and independent. He -neither cringes before a white nor looks up to him as a superior being. -I was greatly impressed by the bearing of the first of the forest tribes -I met in August, 1911, at Santo Anato. I had built a brisk fire and was -enjoying its comfort when La Sama returned with some Indians whom he had -secured to clear his playa. The tallest of the lot, wearing a colored -band of deer skin around his thick hair and a gaudy bunch of yellow -feathers down his back, came up, looked me squarely in the eye, and -asked - -"Tatiry payta?" (What is your name?) - -When I replied he quietly sat down by the fire, helping himself to the -roasted corn I had prepared in the hot ashes. A few days later when we -came to the head of a rapid I was busy sketching-in my topographic map -and did not hear his twice repeated request to leave the boat while the -party reconnoitered the rapid. Watching his opportunity he came -alongside from the rear--he was steersman--and, turning just as he was -leaving the boat, gave me a whack in the forehead with his open palm. La -Sama saw the motion and protested. The surly answer was: - -"I twice asked him to get out and he didn't move. What does he think we -run the canoe to the bank for?" - -To him the making of a map was inexplicable; I was merely a stupid white -person who didn't know enough to get out of a canoe when told! - -The plateau Indian has been kicked about so long that all his -independence has been destroyed. His goods have been stolen, his -services demanded without recompense, in many places he has no right to -land, and his few real rights are abused beyond belief. The difference -between him and the forest Indian is due quite largely to differences of -environment. The plateau Indian is agricultural, the forest Indian -nomadic and in a hunting stage of development; the unforested plateau -offers no means for concealment of person or property, the forest offers -hidden and difficult paths, easy means for concealment, for ambush, and -for wide dispersal of an afflicted tribe. The brutal white of the -plateau follows altogether different methods when he finds himself in -the Indian country, far from military assistance, surrounded by fearless -savages. He may cheat but he does not steal, and his brutality is always -carefully suited to both time and place. - -The Machigangas are now confined to the forest, but the limits of their -territory were once farther upstream, where they were in frequent -conflict with the plateau Indians. As late as 1835, according to General -Miller,[4] they occupied the land as far upstream as the "Encuentro" -(junction) of the Urubamba and the Yanatili (Fig. 53). Miller likewise -notes that the Chuntaguirus, "a superior race of Indians" who lived -"toward the Marañon," came up the river "200 leagues" to barter with the -people thereabouts. - -"They bring parrots and other birds, monkeys, cotton robes white and -painted, wax balsams, feet of the gran bestia, feather ornaments for the -head, and tiger and other skins, which they exchange for hatchets, -knives, scissors, needles, buttons, and any sort of glittering bauble." - -On their yearly excursions they traveled in a band numbering from 200 to -300, since at the mouth of the Paucartambo (Yavero) they were generally -set upon by the Pucapacures. The journey upstream required three months; -with the current they returned home in fifteen days. - -Their place of meeting at the mouth of the Yanatili was a response to a -long strip of grassland that extends down the deep and dry Urubamba -Valley, as shown in Figs. 53-B and 55. The wet forests, in which the -Machigangas live, cover the hills back of the valley plantations; the -belt of dry grassland terminates far within the general limits of the -red man's domain and only 2,000 feet above the sea. It is in this strip -of low grassland that on the one hand the highland and valley dwellers, -and on the other the Indians of the hot forested valleys and the -adjacent lowland found a convenient place for barter. The same -physiographic features are repeated in adjacent valleys of large size -that drain the eastern aspect of the Peruvian Andes, and in each case -they have given rise to the periodic excursions of the trader. - -These annual journeys are no longer made. The planters have crept down -valley. The two best playas below Rosalina are now being cleared. Only a -little space remains between the lowest valley plantations and the -highest rubber stations. Furthermore, the Indians have been enslaved by -the rubber men from the Ucayali. The Machigangas, many of whom are -runaway peons, will no longer take cargoes down valley for fear of -recapture. They have the cautious spirit of fugitives except in their -remote valleys. There they are secure and now and then reassert their -old spirit when a lawless trader tries to browbeat them into an -unprofitable trade. Also, they are yielding to the alluring call of the -planter. At Santo Anato they are clearing a playa in exchange for -ammunition, machetes, brandy, and baubles. They no longer make annual -excursions to get these things. They have only to call at the nearest -plantation. There is always a wolf before the door of the planter--the -lack of labor. Yet, as on every frontier, he turns wolf himself when the -lambs come, and without shame takes a week's work for a penny mirror, -or, worse still, supplies them with firewater, for that will surely -bring them back to him. Since this is expensive they return to their -tribal haunts with nothing except a debauched spirit and an appetite -from which they cannot run away as they did from their task masters in -the rubber forest. Hence the vicious circle: more brandy, more labor; -more labor, more cleared land; more cleared land, more brandy; more -brandy, less Indian. But by that time the planter has a large sugar -estate. Then he can begin to buy the more expensive plateau labor, and -in turn debauch it. - -Nature as well as man works against the scattered tribes of Machigangas -and their forest kinsmen. Their country is exceedingly broken by -ramifying mountain spurs and valleys overhung with cliffs or bordered by -bold, wet, fern-clad slopes. It is useless to try to cut your way by a -direct route from one point to another. The country is mantled with -heavy forest. You must follow the valleys, the ancient trails of the -people. The larger valleys offer smooth sand-bars along the border of -which canoes may be towed upstream, and there are little cultivated -places for camps. But only a few of the tribes live along them, for they -are also more accessible to the rubbermen. The smaller valleys, -difficult of access, are more secure and there the tribal remnants live -today. While the broken country thus offers a refuge to fugitive bands -it is the broken country and its forest cover that combine to break up -the population into small groups and keep them in an isolated and -quarrelsome state. Chronic quarreling is not only the product of mere -lack of contact. It is due to many causes, among which is a union of the -habit of migration and divergent tribal speech. Every tribe has its own -peculiar words in addition to those common to the group of tribes to -which it belongs. Moreover each group of a tribe has its distinctive -words. I have seen and used carefully prepared vocabularies--no two of -which are alike throughout. They serve for communication with only a -limited number of families. These peculiarities increase as experiences -vary and new situations call for additions to or changes in their -vocabularies, and when migrating tribes meet their speech may be so -unlike as to make communication difficult. Thus arise suspicion, -misunderstanding, plunder, and chronic war. Had they been a united -people their defense of their rough country might have been successful. -The tribes have been divided and now and again, to get firearms and -ammunition with which to raid a neighbor, a tribe has joined its -fortunes to those of vagrant rubber pickers only to find in time that -its women were debased, its members decimated by strange and deadly -diseases, and its old morality undermined by an insatiable desire for -strong drink.[5] The Indian loses whether with the white or against him. - -The forest Indian is held by his environment no less strongly than the -plateau Indian. We hear much about the restriction of the plateau -dweller to the cool zone in which the llama may live. As a matter of -fact he lives far below the cool zone, where he no longer depends upon -the llama but rather upon the mule for transport. The limits of his -range correspond to the limits of the grasslands in the dry valley -pockets already described (p. 42), or on the drier mountain slopes below -the zone of heaviest rainfall (Fig. 54). It is this distribution that -brought him into such intimate contact with the forest Indian. The old -and dilapidated coca terraces of the Quechuas above the Yanatili almost -overlook the forest patches where the Machigangas for centuries built -their rude huts. A good deal has been written about the attempts of the -Incas to extend their rule into this forest zone and about the failure -of these attempts on account of the tropical climate. But the forest -Indian was held by bonds equally secure. The cold climate of the plateau -repelled him as it does today. His haunts are the hot valleys where he -need wear only a wild-cotton shirt or where he may go naked altogether. -That he raided the lands of the plateau Indian is certain, but he could -never displace him. Only along the common borders of their domains, -where the climates of two zones merged into each other, could the forest -Indian and the plateau Indian seriously dispute each other's claims to -the land. Here was endless conflict but only feeble trade and only the -most minute exchanges of cultural elements. - -Even had they been as brothers they would have had little incentive to -borrow cultural elements from each other. The forest dweller requires -bow and arrow; the plateau dweller requires a hoe. There are fish in the -warm river shallows of the forested zone; llamas, vicuña, vizcachas, -etc., are a partial source of food supply on the plateau. Coca and -potatoes are the chief products of the grassy mountain slopes; yuca, -corn, bananas, are the chief vegetable foods grown on the tiny -cultivated patches in the forest. The plateau dweller builds a -thick-walled hut; the valley dweller a cane shack. So unlike are the two -environments that it would be strange if there had been a mixture of -racial types and cultures. The slight exchanges that were made seem -little more than accidental. Even today the Machigangas who live on the -highest slopes own a few pigs obtained from Quechuas, but they never eat -their flesh; they keep them for pets merely. I saw not a single woolen -article among the Indians along the Urubamba whereas Quechuas with -woolen clothing were going back and forth regularly. Their baubles were -of foreign make; likewise their few hoes, likewise their guns. - -They clear the forest about a mid-cotton tree and spin and weave the -cotton fiber into sacks, cords for climbing trees when they wish to -chase a monkey, ropes for hauling their canoes, shirts for the married -men and women, colored head-bands, and fish nets. The slender strong -bamboo is gathered for arrows. The chunta palm, like bone for hardness, -supplies them with bows and arrow heads. The brilliant red and yellow -feathers of forest birds, also monkey bones and teeth, are their natural -ornaments. Their life is absolutely distinct from that of their Quechua -neighbors. Little wonder that for centuries forest and plateau Indians -have been enemies and that their cultures are so distinct, for their -environment everywhere calls for unlike modes of existence and distinct -cultural development. - - - - -CHAPTER V - -THE COUNTRY OF THE SHEPHERDS - - -The lofty mountain zones of Peru, the high bordering valleys, and the -belts of rolling plateau between are occupied by tribes of shepherds. In -that cold, inhospitable region at the top of the country are the highest -permanent habitations in the world--17,100 feet (5,210 m.)--the loftiest -pastures, the greatest degree of adaptation to combined altitude and -frost. It is here only a step from Greenland to Arcady. Nevertheless it -is Greenland that has the people. Why do they shun Arcady? To the -traveler from the highlands the fertile valleys between 5,000 and 8,000 -feet (1,500 to 2,500 m.) seem like the abode of friendly spirits to -whose charm the highland dweller must yield. Every pack-train from -valley to highland carries luxury in the form of fruit, coca, cacao, and -sugar. One would think that every importation of valley products would -be followed by a wave of migration from highland to valley. On the -contrary the highland people have clung to their lofty pastures for -unnumbered centuries. Until the Conquest the last outposts of the Incas -toward the east were the grassy ridges that terminate a few thousand -feet below the timber line. - -In this natural grouping of the people where does choice or blind -prejudice or instinct leave off? Where does necessity begin? There are -answers to most of these questions to be found in the broad field of -geographic comparison. But before we begin comparisons we must study the -individual facts upon which they rest. These facts are of almost every -conceivable variety. They range in importance from a humble shepherd's -stone corral on a mountain slope to a thickly settled mountain basin. -Their interpretation is to be sought now in the soil of rich playa -lands, now in the fixed climatic zones and rugged relief of deeply -dissected, lofty highlands in the tropics. Some of the controlling -factors are historical, others economic; still other factors have -exerted their influence through obscure psychologic channels almost -impossible to trace. The _why_ of man's distribution over the earth is -one of the most complicated problems in natural science, and the -solution of it is the chief problem of the modern geographer. - -At first sight the mountain people of the Peruvian Andes seem to be -uniform in character and in mode of life. The traveler's first -impression is that the same stone-walled, straw-thatched type of hut is -to be found everywhere, the same semi-nomadic life, the same degrees of -poverty and filth. Yet after a little study the diversity of their lives -is seen to be, if not a dominating fact, at least one of surprising -importance. Side by side with this diversity there runs a corresponding -diversity of relations to their physical environment. Nowhere else on -the earth are greater physical contrasts compressed within such small -spaces. If, therefore, we accept the fundamental theory of geography -that there is a general, necessary, varied, and complex relation between -man and the earth, that theory ought here to find a really vast number -of illustrations. A glance at the accompanying figures discloses the -wide range of relief in the Peruvian Andes. The corresponding range in -climate and in life therefore furnishes an ample field for the -application of the laws of human distribution. - -In analyzing the facts of distribution we shall do well to begin with -the causes and effects of migration. Primitive man is in no small degree -a wanderer. His small resources often require him to explore large -tracts. As population increases the food quest becomes more intense, and -thus there come about repeated emigrations which increase the food -supply, extend its variety, and draw the pioneers at last into contact -with neighboring groups. The farther back we go in the history of the -race the clearer it becomes that migrations lie at the root of much of -human development. The raid for plunder, women, food, beasts, is a -persistent feature of the life of those primitive men who live on the -border of unlike regions. - -The shepherd of the highland and the forest hunter of the plains -perforce range over vast tracts, and each brings back to the home group -news that confirms the tribal choice of habitation or sets it in motion -toward a more desirable place. Superstitions may lead to flight akin to -migration. Epidemics may be interpreted as the work of a malignant -spirit from which men must flee. War may drive a defeated group into the -fastnesses of a mountain forest where pursuit by stream or trail weakens -the pursuer and confines his action, thereby limiting his power. Floods -may come and destroy the cultivated spots. Want or mere desire in a -hundred forms may lead to movement. - -Even among forest tribes long stationary the facile canoe and the light -household necessities may easily enable trivial causes to develop the -spirit of restlessness. Pressure of population is a powerful but not a -general cause of movement. It may affect the settled groups of the -desert oases, or the dense population of fertile plains that is rooted -in the soil. On the other hand mere whims may start a nomadic group -toward a new goal. Often the goal is elusive and the tribe turns back to -the old haunts or perishes in the shock of unexpected conflict. - -In the case of both primitive societies and those of a higher order the -causes and the results of migration are often contradictory. These will -depend on the state of civilization and the extremes of circumstance. -When the desert blooms the farmer of the Piura Valley in northwestern -Peru turns shepherd and drives his flocks of sheep and goats out into -the short-lived pastures of the great pampa on the west. In dry years he -sends them eastward into the mountains. The forest Indian of the lower -Urubamba is a fisherman while the river is low and lives in a reed hut -beside his cultivated patch of cane and yuca. When the floods come he is -driven to the higher ground in the hills where he has another cultivated -patch of land and a rude shelter. To be sure, these are seasonal -migrations, yet through them the country becomes better known to each -new generation of men. And each generation supplies its pioneers, who -drift into the remoter places where population is scarce or altogether -wanting. - -[Illustration: FIG. 24--This stone hut, grass-thatched, is the highest -permanent habitation in Peru, and is believed to be the highest in the -world. Altitude of 17,100 feet (5,210 m.) determined by instrumental -survey. The general geographic relationships of the region in which the -hut is situated are shown in Fig. 25. For location see the topographic -map, Fig. 204.] - -Dry years and extremely dry years may have opposite effects. When -moderate dryness prevails the results may be endurable. The oases -become crowded with men and beasts just when they can ill afford to -support them. The alfalfa meadows become overstocked and cattle become -lean and almost worthless. But there is at least bare subsistence. By -contrast, if extreme and prolonged drought prevails, some of the people -are driven forth to more favored spots. At Vallenar in central Chile -some of the workmen in extreme years go up to the nitrate pampa; in wet -years they return. When the agents of the nitrate companies hear of hard -times in a desert valley they offer employment to the stricken people. -It not infrequently happens that when there are droughts in desert Chile -there are abundant rains in Argentina on the other side of the -Cordillera. There has therefore been for many generations an irregular -and slight, though definite, shifting of population from one side of the -mountains to the other as periods of drought and periods of rain -alternated in the two regions. Some think there is satisfactory evidence -to prove that a number of the great Mongolian emigrations took place in -wet years when pasture was abundant and when the pastoral nomad found it -easy to travel. On the other hand it has been urged that the cause of -many emigrations was prolonged periods of drought when the choice lay -between starvation and flight. It is evident from the foregoing that -both views may be correct in spite of the fact that identical effects -are attributed to opposite causes. - -[Illustration: FIG. 25--Regional diagram for the Maritime Cordillera to -show the physical relations in the district where the highest habitation -in the world are located. For location, see Fig. 20. It should be -remembered that the orientation of these diagrams is generalized. By -reference to Fig. 20 it will be seen that some portions of the crest of -the Maritime Cordillera run east and west and others north and south. -The same is true of the Cordillera Vilcapampa, Fig. 36.] - - _Note on regional diagrams._--For the sake of clearness I have - classified the accompanying facts of human distribution in the - country of the shepherds and represented them graphically in - "regional" diagrams, Figs. 17, 25, 26, 32, 34, 36, 42, 65. These - diagrams are constructed on the principle of dominant control. Each - brings out the factors of greatest importance in the distribution - of the people in a given region. Furthermore, the facts are - compressed within the limits of a small rectangle. This - compression, though great, respects all essential relations. For - example, every location on these diagrams has a concrete - illustration but the accidental relations of the field have been - omitted; the essential relations are preserved. Each diagram is, - therefore, a kind of generalized type map. It bears somewhat the - same relation to the facts of human geography that a block diagram - does to physiography. The darkest shading represents steep - snow-covered country; the next lower grade represents rough but - snow-free country; the lightest shading represents moderate relief; - unshaded parts represent plain or plateau. Small circles represent - forest or woodland; small open-spaced dots, grassland. Fine - alluvium is represented by small closely spaced dots; coarse - alluvium by large closely spaced dots. - - To take an illustration. In Figure 32 we have the Apurimac region - near Pasaje (see location map, Fig. 20). At the lower edge of the - rectangle is a snow-capped outlier of the Cordillera Vilcapampa. - The belt of rugged country represents the lofty, steep, exposed, - and largely inaccessible ridges at the mid-elevations of the - mountains below the glaciated slopes at the heads of tributary - valleys. The villages in the belt of pasture might well be - Incahuasi and Corralpata. The floors of the large canyons on either - hand are bordered by extensive alluvial fans. The river courses are - sketched in a diagrammatic way only, but a map would not be - different in its general disposition. Each location is justified by - a real place with the same essential features and relations. In - making the change there has been no alteration of the general - relation of the alluvial lands to each other or to the highland. By - suppressing unnecessary details there is produced a diagram whose - essentials have simple and clear relations. When such a regional - diagram is amplified by photographs of real conditions it becomes a - sort of generalized picture of a large group of geographic facts. - One could very well extend the method to the whole of South - America. It would be a real service to geography to draw up a set - of, say, twelve to fifteen regional diagrams, still further - generalized, for the whole of the continent. As a broad - classification they would serve both the specialist and the general - student. As the basis for a regional map of South America they - would be invaluable if worked out in sufficient detail and - constructed on the indispensable basis of field studies. - -It is still an open question whether security or insecurity is more -favorable for the broad distribution of the Peruvian Indians of the -mountain zone which forms the subject of this chapter. Certainly both -tend to make the remoter places better known. Tradition has it that, in -the days of intertribal conflict before the Conquest, fugitives fled -into the high mountain pastures and lived in hidden places and in caves. -Life was insecure and relief was sought in flight. On the other hand -peace has brought security to life. The trails are now safe. A shepherd -may drive his flock anywhere. He no longer has any one to fear in his -search for new pastures. It would perhaps be safe to conclude that there -is equally broad distribution of men in the mountain pastures in time of -peace and in time of war. There is, however, a difference in the kind -of distribution. In time of peace the individual is safe anywhere; in -time of unrest he is safe only when isolated and virtually concealed. By -contrast, the group living near the trails is scattered by plundering -bands and war parties. The remote and isolated group may successfully -oppose the smaller band and the individuals that might reach the remoter -regions. The fugitive group would have nothing to fear from large bands, -for the limited food supply would inevitably cause these to disintegrate -upon leaving the main routes of travel. Probably the fullest exploration -of the mountain pastures has resulted from the alternation of peace and -war. The opposite conditions which these establish foster both kinds of -distribution; hence both the remote group life encouraged by war and the -individual's lack of restraint in time of peace are probably in large -part responsible for the present widespread occupation of the Peruvian -mountains. - -The loftiest habitation in the world (Fig. 24) is in Peru. Between -Antabamba and Cotahuasi occur the highest passes in the Maritime -Cordillera. We crossed at 17,400 feet (5,300 m.), and three hundred feet -lower is the last outpost of the Indian shepherds. The snowline, very -steeply canted away from the sun, is between 17,200 and 17,600 feet -(5,240 to 5,360 m.). At frequent intervals during the three months of -winter, snowfalls during the night and terrific hailstorms in the late -afternoon drive both shepherds and flocks to the shelter of leeward -slopes or steep canyon walls. At our six camps, between 16,000 and -17,200 feet (4,876 and 5,240 m.), in September, 1911, the minimum -temperature ranged from 4° to 20°F. The thatched stone hut that we -passed at 17,100 feet and that enjoys the distinction of being the -highest in the world was in other respects the same as the thousands of -others in the same region. It sheltered a family of five. As we passed, -three rosy-cheeked children almost as fat as the sheep about them were -sitting on the ground in a corner of the corral playing with balls of -wool. Hundreds of alpacas and sheep grazed on the hill slopes and valley -floor, and their tracks showed plainly that they were frequently driven -up to the snowline in those valleys where a trickle of water supported a -band of pasture. Less than a hundred feet below them were other huts and -flocks. - -Here we have the limits of altitude and the limits of resources. The -intervalley spaces do not support grass. Some of them are quite bare, -others are covered with mosses. It is too high for even the tola -bush--that pioneer of Alpine vegetation in the Andes. The distance[6] to -Cotahuasi is 75 miles (120 km.), to Antabamba 50 miles (80 km.). Thence -wool must be shipped by pack-train to the railroad in the one case 250 -miles (400 km.) to Arequipa, in the other case 200 miles (320 km.) to -Cuzco. Even the potatoes and barley, which must be imported, come from -valleys several days' journey away. The question naturally arises why -these people live on the rim of the world. Did they seek out these -neglected pastures, or were they driven to them? Do they live here by -choice or of necessity? The answer to these questions introduces two -other geographic factors of prime importance, the one physical, the -other economic. - -The main tracts of lofty pasture above Antabamba cover mountain slopes -and valley floor alike, but the moist valley floors supply the best -grazing. Moreover, the main valleys have been intensively glaciated. -Hence, though their sides are steep walls, their floors are broad and -flat. Marshy tracts, periodically flooded, are scattered throughout, and -here and there are overdeepened portions where lakes have gathered. -There is a thick carpet of grass, also numerous huts and corrals, and -many flocks. At the upper edge of the main zone of pasture the grasses -become thin and with increasing altitude give out altogether except -along the moist valley floors or on shoulders where there is seepage. - -If the streams head in dry mountain slopes without snow the grassy bands -of the valley floor terminate at moderate elevations. If the streams -have their sources in snowfields or glaciers there is a more uniform -run-off, and a ribbon of pasture may extend to the snowline. To the -latter class belong the pastures that support these remote people. - -In the case of the Maritime Andes the great elevation of the snowline is -also a factor. If, in Figure 25, we think of the snowline as at the -upper level of the main zone of pasture then we should have the -conditions shown in Figure 36, where the limit of general, not local, -occupation is the snowline, as in the Cordillera Vilcapampa and between -Chuquibambilla and Antabamba. - -A third factor is the character of the soil. Large amounts of volcanic -ash and lapilli were thrown out in the late stages of volcanic eruption -in which the present cones of the Maritime Andes were formed. The coarse -texture of these deposits allows the ready escape of rainwater. The -combination of extreme aridity and great elevation results in a double -restraint upon vegetation. Outside of the moist valley floors, with -their film of ground moraine on whose surface plants find a more -congenial soil, there is an extremely small amount of pasture. Here are -the natural grazing grounds of the fleet vicuña. They occur in -hundreds, and so remote and little disturbed are they that near the main -pass one may count them by the score. As we rode by, many of them only -stared at us without taking the trouble to get beyond rifle shot. It is -not difficult to believe that the Indians easily shoot great numbers in -remote valleys that have not been hunted for years. - -The extreme conditions of life existing on these lofty plateaus are well -shown by the readiness with which even the hardy shepherds avail -themselves of shelter. Wherever deep valleys bring a milder climate -within reach of the pastures the latter are unpopulated for miles on -either side. The sixty-mile stretch between Chuquibamba and Salamanca is -without even a single hut, though there are pastures superior to the -ones occupied by those loftiest huts of all. Likewise there are no -permanent homes between Salamanca and Cotahuasi, though the shepherds -migrate across the belt in the milder season of rain. Eastward and -northward toward the crest of the Maritime Cordillera there are no huts -within a day's journey of the Cotahuasi canyon. Then there is a group of -a dozen just under the crest of the secondary range that parallels the -main chain of volcanoes. Thence northward there are a number of -scattered huts between 15,500 and 16,500 feet (4,700 and 5,000 m.), -until we reach the highest habitations of all at 17,100 feet (5,210m.). - -[Illustration: FIG. 26--Regional diagram to show the physical relations -in the lava plateau of the Maritime Cordillera west of the continental -divide. For location, see Fig. 20. Trails lead up the intrenched -tributaries. If the irrigated bench (lower right corner) is large, a -town will be located on it. Shepherds' huts are scattered about the edge -of the girdle of spurs. There is also a string of huts in the deep -sheltered head of each tributary. See also Fig. 29 for conditions on the -valley or canyon floor.] - -The unpopulated belts of lava plateau bordering the entrenched valleys -are, however, as distinctly "sustenance" spaces, to use Penck's term, as -the irrigated and fertile alluvial fans in the bottom of the valley. -This is well shown when the rains come and flocks of llamas and sheep -are driven forth from the valleys to the best pastures. It is equally -well shown by the distribution of the shepherds' homes. These are not -down on the warm canyon floor, separated by a half-day's journey from -the grazing. They are in the intrenched tributary valleys of Figure 26 -or just within the rim of the canyon. It is not shelter from the cold -but from the wind that chiefly determines their location. They are also -kept near the rim of the canyon by the pressure of the farming -population from below. Every hundred feet of descent from the arid -plateau (Fig. 29) increases the water supply. Springs increase in number -and size; likewise belts of seepage make their appearance. The gradients -in many places diminish, and flattish spurs and shoulders interrupt the -generally steep descents of the canyon wall. Every change of this sort -has a real value to the farmer and means an enhanced price beyond the -ability of the poor shepherd to pay. If you ask a wealthy _hacendado_ on -the valley floor (Fig. 29), who it is that live in the huts above him, -he will invariably say "los Indios," with a shrug meant to convey the -idea of poverty and worthlessness. Sometimes it is "los Indios pobres," -or merely "los pobres." Thus there is a vertical stratification of -society corresponding to the superimposed strata of climate and land. - -At Salamanca (Fig. 62) I saw this admirably displayed under -circumstances of unusual interest. The floor and slopes of the valley -are more completely terraced than in any other valley I know of. In the -photograph, Fig. 30, which shows at least 2,500 feet of descent near the -town, one cannot find a single patch of surface that is not under -cultivation. The valley is simply filled with people to the limit of its -capacity. Practically all are Indians, but with many grades of wealth -and importance. When we rode out of the valley before daybreak, one -September morning in 1911, there was a dead calm, and each step upward -carried us into a colder stratum of air. At sunrise we had reached a -point about 2,000 feet above the town, or 14,500 feet (4,420 m.) above -sea level. We stood on the frost line. On the opposite wall of the -valley the line was as clearly marked out as if it had been an -irrigating canal. The light was so fully reflected from the millions of -frost crystals above it that both the mountainside and the valley slopes -were sparkling like a ruffled lake at sunrise. Below the frost line the -slopes were dark or covered with yellow barley and wheat stubble or -green alfalfa. - -It happened that the frost line was near the line of division between -corn and potato cultivation and also near the line separating the steep -rough upper lands from the cultivable lower lands. Not a habitation was -in sight above us, except a few scattered miserable huts near broken -terraces, gullied by wet-weather streams and grown up to weeds and -brush. Below us were well-cultivated fields, and the stock was kept in -bounds by stone fences and corrals; above, the half-wild burros and -mules roamed about everywhere, and only the sheep and llamas were in -rude enclosures. Thus in a half hour we passed the frontier between the -agricultural folk below the frost line and the shepherd folk above it. - -[Illustration: FIG. 27--Terraced valley slopes at Huaynacotas, Cotahuasi -Valley, Peru. Elevation 11,500 feet (3,500 m.).] - -[Illustration: FIG. 28--The highly cultivated and thoroughly terraced -floor of the Ollantaytambo Valley at Ollantaytambo. This is a tributary -of the Urubamba; elevation, 11,000 feet.] - -[Illustration: FIG. 29--Cotahuasi on the floor of the Cotahuasi canyon. -The even skyline of the background is on a rather even-topped lava -plateau. The terrace on the left of the town is formed on limestone, -which is overlain by lava flows. A thick deposit of terraced alluvium -may be seen on the valley floor, and it is on one of the lower terraces -that the city of Cotahuasi stands. The higher terraces are in many cases -too dry for cultivation. The canyon is nearly 7,000 feet (2,130 m.) deep -and has been cut through one hundred principal lava flows.] - -In a few spots the line followed an irregular course, as where flatter -lands were developed at unusual elevations or where air drainage altered -the normal temperature. And at one place the frost actually stood on -the young corn, which led us to speculate on the possibility of securing -from Salamanca a variety of maize that is more nearly resistant to light -frosts than any now grown in the United States. In the endless and -largely unconscious experimentation of these folk perched on the valley -walls a result may have been achieved ahead of that yet reached by our -professional experimenters. Certain it is that nowhere else in the world -has the potato been grown under such severe climatic conditions as in -its native land of Peru and Bolivia. The hardiest varieties lack many -qualities that we prize. They are small and bitter. But at least they -will grow where all except very few cultivated plants fail, and they are -edible. Could they not be imported into Canada to push still farther -northward the limits of cultivation? Potatoes are now grown at Forts -Good Hope and McPherson in the lower Mackenzie basin. Would not the -hardiest Peruvian varieties grow at least as far north as the -continental timber line? I believe they could be grown still farther -north. They will endure repeated frosts. They need scarcely any -cultivation. Prepared in the Peruvian manner, as _chuño_, they could be -kept all winter. Being light, the meal derived from them could be easily -packed by hunters and prospectors. An Indian will carry in a pouch -enough to last him a week. Why not use it north of the continental limit -of other cultivated plants since it is the pioneer above the frost line -on the Peruvian mountains? - -The relation between farmer and shepherd or herdsman grows more complex -where deeper valleys interrupt the highlands and mountains. The -accompanying sketch, Fig. 32, represents typical relations, though based -chiefly on the Apurimac canyon and its surroundings near Pasaje. First -there is the snow-clad region at the top of the country. Below it are -grassy slopes, the homes of mountain shepherds, or rugged mountain -country unsuited for grazing. Still lower there is woodland, in patches -chiefly, but with a few large continuous tracts. The shady sides of the -ravines and the mountains have the most moisture, hence bear the densest -growths. Finally, the high country terminates in a second belt of -pasture below the woodland. - -[Illustration: FIG. 32--Regional diagram representing the deep canyoned -country west of the Eastern Cordillera in the region of the Apurimac. -For photograph see Fig. 94. For further description see note on regional -diagrams, p. 51. Numbers 1, 2, and 3 correspond in position to the same -numbers in Fig. 33.] - -[Illustration: FIG. 30--Terraced hill slopes near Salamanca. There is no -part of the photograph which is not covered with terraces save a few -places where bushy growths are visible or where torrents descend through -artificial canals.] - -[Illustration: FIG. 31--Alpine pastures in the mountain valley between -Chuquibambilla and Lambrama. Huge stone corrals are built on either -slope, sheltered from the night winds that blow down-valley.] - -Whenever streams descend from the snow or woodland country there is -water for the stock above and for irrigation on the alluvial fan below. -But the spur ends dropping off abruptly several thousand feet have a -limited area and no running streams, and the ground water is hundreds of -feet down. There is grass for stock, but there is no water. In some -places the stock is driven back and forth every few days. In a few -places water is brought to the stock by canal from the woodland streams -above, as at Corralpata.[7] In the same way a canal brings water to -Pasaje hacienda from a woodland strip many miles to the west. The little -canal in the figure is almost a toy construction a few inches wide and -deep and conveying only a trickle of water. Yet on it depends the -settlement at the spur end, and if it were cut the people would have to -repair it immediately or establish new homes. - -[Illustration: FIG. 33--Valley climates of the canyoned region shown in -Fig. 32.] - -The canal and the pasture are possible because the slopes are moderate. -They were formed in an earlier cycle of erosion when the land was lower. -They are hung midway between the rough mountain slopes above and the -steep canyon walls below (Fig. 32). Their smooth descents and gentle -profiles are in very pleasing contrast to the rugged scenery about them. -The trails follow them easily. Where the slopes are flattest, farmers -have settled and produce good crops of corn, vegetables, and barley. -Some farmers have even developed three-and four-story farms. On an -alluvial fan in the main valley they raise sugar cane and tropical and -subtropical fruits; on the flat upper slopes they produce corn; in the -moister soil near the edge of the woodland are fields of mountain -potatoes; and the upper pastures maintain flocks of sheep. In one -district this change takes place in a distance that may be covered in -five hours. Generally it is at least a full and hard day's journey from -one end of the series to the other. - -Wherever these features are closely associated they tend to be -controlled by the planter in some deep valley thereabouts. Where they -are widely scattered the people are independent, small groups living in -places nearly inaccessible. Legally they are all under the control of -the owners of princely tracts that take in the whole country, but the -remote groups are left almost wholly to themselves. In most cases they -are supposed to sell their few commercial products to the _hacendado_ -who nominally owns their land, but the administration of this -arrangement is left largely to chance. The shepherds and small farmers -near the plantation are more dependent upon the planter for supplies, -and also their wants are more varied and numerous. Hence they pay for -their better location in free labor and in produce sold at a discount. - -So deep are some of the main canyons, like the Apurimac and the -Cotahuasi, that their floors are arid or semi-arid. The fortunes of -Pasaje are tied to a narrow canal from the moist woodland and a tiny -brook from a hollow in the valley wall. Where the water has thus been -brought down to the arable soil of the fans there are rich plantations -and farms. Elsewhere, however, the floor is quite dry and uncultivated. -In small spots here and there is a little seepage, or a few springs, or -a mere thread of water that will not support a plantation, wherefore -there have come into existence the valley herdsmen and shepherds. Their -intimate knowledge of the moist places is their capital, quite as much -as are the cattle and sheep they own. In a sense their lands are the -neglected crumbs from the rich man's table. So we find the shepherd from -the hills invading the valleys just as the valley farmer has invaded the -country of the shepherd. - -[Illustration: FIG. 34--Regional diagram to show the typical physical -conditions and relations in an intermont basin in the Peruvian Andes. -The Cuzco basin (see Fig. 37) is an actual illustration; it should, -however, be emphasized that the diagram is not a "map" of that basin, -for whilst conditions there have been utilized as a basis, the -generalization has been extended to illustrate many basins.] - -The basin type of topography calls into existence a set of relations -quite distinct from either of those we have just described. Figure 34 -represents the main facts. The rich and comparatively flat floor of the -basin supports most of the people. The alluvial fans tributary thereto -are composed of fine material on their outer margin and of coarse stony -waste at their heads. Hence the valley farms also extend over the edges -of the fans, while only pasture or dense chaparral occupies the upper -portions. Finally there is the steep margin of the basin where the -broad and moderate slopes of the highland break down to the floor of the -basin. - -[Illustration: FIG. 35--Climatic cross-section showing the location of -various zones of cultivation and pasture in a typical intermont basin in -the Peruvian Andes. The thickness of the dark symbols on the right is -proportional to the amount of each staple that is produced at the -corresponding elevation. See also the regional diagram Fig. 34.] - -If a given basin lies at an elevation exceeding 14,000 feet (4,270 m.), -there will be no cultivation, only pasture. If at 10,000 or 11,000 feet -(3,000 or 3,350 m.), there will be grain fields below and potato fields -above (Figs. 34 and 35). If still lower, fruit will come in and finally -sugar cane and many other subtropical products, as at Abancay. Much will -also depend upon the amount of available water and the extent of the -pasture land. Thus the densely populated Cuzco basin has a vast mountain -territory tributary to it and is itself within the limits of barley and -wheat cultivation. Furthermore there are a number of smaller basins, -like the Anta basin on the north, which are dependent upon its better -markets and transportation facilities. A dominance of this kind is -self-stimulating and at last is out of all proportion to the original -differences of nature. Cuzco has also profited as the gateway to the -great northeastern valley region of the Urubamba and its big -tributaries. All of the varied products of the subtropical valleys find -their immediate market at Cuzco. - -The effect of this natural conspiracy of conditions has been to place -the historic city of Cuzco in a position of extraordinary importance. -Hundreds of years before the Spanish Conquest it was a center of -far-reaching influence, the home of the powerful Inca kings. From it the -strong arm of authority and conquest was extended; to it came tribute -of grain, wool, and gold. To one accustomed to look at such great -consequences as having at least some ultimate connection with the earth, -the situation of Cuzco would be expected to have some unique features. -With the glorious past of that city in mind, no one can climb to the -surrounding heights and look down upon the fertile mountain-rimmed plain -as at an ordinary sight (Fig. 37). The secret of those great conquests -lies not only in mind but in matter. If the rise of the Incas to power -was not related to the topography and climate of the Cuzco basin, at -least it is certain that without so broad and noble a stage the scenes -would have been enacted on a far different scale. - -The first Inca king and the Spanish after the Incas found here no mobile -nomadic tribes melting away at the first touch, no savages hiding in -forest fastnesses, but a well-rooted agricultural race in whose center a -large city had grown up. Without a city and a fertile tributary plain no -strong system of government could be maintained or could even arise. It -is a great advantage in ruling to have subjects that cannot move. The -agricultural Indians of the Andean valleys and basins, in contrast to -the mobile shepherd, are as fixed as the soil from which they draw their -life. - -The full occupation of the pasture lands about the Cuzco basin is in -direct relation to the advantages we have already enumerated. Every part -of the region feels the pressure of population. Nowhere else in the -Peruvian Andes are the limits between cultivation and grazing more -definitely drawn than here. Moreover, there is today a marked difference -between the types that inhabit highland and basin. The basin Indian is -either a debauched city dweller or, as generally, a relatively alert -farmer. The shepherds are exceedingly ignorant and live for the most -part in a manner almost as primitive as at the time of the Conquest. -They are shy and suspicious. Many of them prefer a life of isolation and -rarely go down to the town. They live on the fringe of culture. The new -elements of their life have come to them solely by accident and by what -might be called a process of ethnic seepage. The slight advances that -have been made do not happen by design, they merely happen. Put the -highland shepherd in the basin and he would starve in competition with -the basin type. Undoubtedly he would live in the basin if he could. He -has not been driven out of the basin; he is kept out. - -And thus it is around the border of the Abancay basin and others like -it. Only, the Abancay basin is lower and more varied as to resources. -The Indian is here in competition with the capitalistic white planter. -He lives on the land by sufferance alone. Farther up the slopes are the -farms of the Indians and above them are the pastures of the ignorant -shepherds. Whereas the Indian farmer who raises potatoes clings chiefly -to the edge of the Cuzco basin where lie the most undesirable -agricultural lands, the Indian farmers of Abancay live on broad rolling -slopes like those near the pass northward toward Huancarama. They are -unusually prosperous, with fields so well cultivated and fenced, so -clean and productive, that they remind one somewhat of the beautiful -rolling prairies of Iowa. - -It remains to consider the special topographic features of the mountain -environments we are discussing, in the Vilcapampa region on the eastern -border of the Andes (Fig. 36). The Cordillera Vilcapampa is -snow-crested, containing a number of fine white peaks like Salcantay, -Soray, and Soiroccocha (Fig. 140). There are many small glaciers and a -few that are several miles long. There was here in glacial times a much -larger system of glaciers, which lived long enough to work great changes -in the topography. The floors of the glaciated valleys were smoothed and -broadened and their gradients flattened (Figs. 137 and 190). The side -walls were steepened and precipitous cirques were formed at the valley -heads. Also, there were built across the valleys a number of stony -morainic ridges. With all these changes there was, however, but little -effect upon the main masses of the big intervalley spurs. They remain as -before--bold, wind-swept, broken, and nearly inaccessible. - -[Illustration: FIG. 36--Regional diagram for the Eastern Cordillera or -Cordillera Vilcapampa. Note the crowded zones on the right (east and -north) in contrast to the open succession on the left. In sheltered -places woodland extends even higher than shown. At several points -patches of it grow right under the snowline. Other patches grow on the -floors of the glaciated valley troughs.] - -The work of the glaciers aids the mountain people. The stony moraines -afford them handy sizable building material for their stone huts and -their numerous corrals. The thick tufts of grass in the marshy spots in -the overdeepened parts of the valleys furnish them with grass for their -thatched roofs. And, most important of all, the flat valley floors have -the best pasture in the whole mountain region. There is plenty of water. -There is seclusion, and, if a fence be built from one valley wall to -another as can be done with little labor, an entire section of the -valley may be inclosed. A village like Choquetira, located on a bench on -the valley side, commands an extensive view up and down the valley--an -important feature in a grazing village where the corrals cannot always -be built near the houses of the owners. Long, finger-like belts of -highland-shepherd population have thus been extended into the mountain -valleys. Sheep and llamas drift right up to the snowline. - -There is, however, a marked difference between the people on opposite -sides of the Cordillera Vilcapampa. On the west the mountains are -bordered by a broad highland devoted to grazing. On the east there is a -narrower grazing belt leading abruptly down to tropical valleys. The -eastern or leeward side is also the warmer and wetter side of the -Cordillera. The snowline is several hundred feet lower on the east. The -result is that patches of scrub and even a little woodland occur almost -at the snowline in favored places. Mist and storms are more frequent. -The grass is longer and fresher. Vegetation in general is more abundant. -The people make less of wool than of cattle, horses, and mules. -Vilcabamba pueblo is famous for its horses, wiry, long-haired little -beasts, as hardy as Shetland ponies. We found cattle grazing only five -hundred feet below the limit of perpetual snow. There are cultivated -spots only a little farther down, and only a thousand feet below the -snow are abandoned terraces. At the same elevation are twisted quenigo -trees, at least two hundred years old, as shown by their rings of -growth. Thus the limits of agriculture are higher on the east; likewise -the limits of cattle grazing that naturally goes with agriculture. Sheep -would thrive, but llamas do better in drier country, and the shepherd -must needs mix his flocks, for the wool which is his chief product -requires transportation and only the cheap and acclimated llama is at -the shepherd's disposal. From these facts it will be seen that the -anthropo-geographic contrasts between the eastern and western sides of -the Cordillera Vilcapampa are as definite as the climatic and vegetal -contrasts. This is especially well shown in the differences between dry -Arma, deep-sunk in a glaciated valley west of the crest of the -mountains, and wet Puquiura, a half-day's journey east of the crest. -There is no group on the east at all comparable to the shepherds of -Choquetira, either in the matter of thorough-going dependence upon -grazing or in that of dependence upon glacial topography. - -[Illustration: FIG. 37--Cuzco and a portion of the famous Cuzco basin -with bordering grassy highlands.] - -[Illustration: FIG. 38--Terraced valley slopes and floor, Urubamba -Valley between Urubamba and Ollantaytambo.] - -[Illustration: FIG. 39--Huichihua, near Chuquibambilla, a typical -mountain village, in the valleys of the Central Ranges, Peruvian Andes.] - -[Illustration: FIG. 40--Potato fluid above Vilcabamba at 12,000 feet -(3,660 m.). The natural sod is broken by a steel-shod stick and the seed -potato dropped into a mere puncture. It receives no attention thereafter -until harvest time.] - -Topography is not always so intimately related to the life of the people -as here. In our own country the distribution of available water is a far -greater factor. The Peruvian Andes therefore occupy a distinctive place -in geography, since, more nearly than in most mountains, their physical -conditions have typical human relations that enable one clearly to -distinguish the limits of control of each feature of climate or relief. - - - - -CHAPTER VI - -THE BORDER VALLEYS OF THE EASTERN ANDES - - -[Illustration: FIG. 41--Regional diagram of the eastern aspect of the -Cordillera Vilcapampa. See also Fig. 17 of which this is an enlarged -section.] - -On the northeastern border of the Peruvian Andes long mountain spurs -trail down from the regions of snow to the forested plains of the -Amazon. Here are the greatest contrasts in the physical and human -geography of the Andean Cordillera. So striking is the fact that every -serious student of Peru finds himself compelled to cross and recross -this natural frontier. The thread of an investigation runs irregularly -now into one border zone, now into another. Out of the forest came the -fierce marauders who in the early period drove back the Inca pioneers. -Down into the forest to escape from the Spaniards fled the last Inca and -his fugitive court. Here the Jesuit fathers sowed their missions along -the forest margin, and watched over them for two hundred years. From the -mountain border one rubber project after another has been launched into -the vast swampy lowlands threaded by great rivers. As an ethnic boundary -the eastern mountain border of Peru and Bolivia has no equal elsewhere -in South America. From the earliest antiquity the tribes of the -grass-covered mountains and the hordes of the forested plains have had -strongly divergent customs and speech, that bred enduring hatred and led -to frequent and bloody strife. - -[Illustration: FIG. 42--Rug weaver at Cotahuasi. The industry is limited -to a small group of related families, living in the Cotahuasi Canyon -near Cotahuasi. The rugs are made of alpaca wool. Pure black, pure -white, and various shades of mixed gray wool are employed. The result is -that the rugs have "fast" colors that always retain their original -contrasts. They are made only to order at the homes of the purchasers. -The money payment is small, but to it is added board and lodging, -besides tobacco, liqueurs, and wine. Before drinking they dip their -finger-tips in the wine and sprinkle the earth "that it may be -fruitful," the air "that it may be warm," the rug "that it may turn out -well," and finally themselves, making the sign of the cross. Then they -set to work.] - -[Illustration: FIG. 43--The floor of the Urubamba Valley from Tarai. The -work of the glaciers was not confined to the lofty situations. Mountain -débris was delivered to all the streams, many of which aggraded their -floors to a depth of several hundred feet, thus increasing the extent of -arable soil at elevations where a less rigorous climate permits the -production of crops and encourages intensive cultivation.] - -On the steepest spurs of the Pampaconas Valley the traveler may go from -snow to pasture in a half day and from pasture to forest in the same -time. Another day he is in the hot zone of the larger valley floors, the -home of the Machigangas. The steep descents bring out the superimposed -zones with diagrammatic simplicity. The timber line is as sharply marked -as the edge of a cultivated field. At a point just beyond the huts of -Pampaconas one may stand on a grassy spur that leads directly up--a -day's journey--to the white summits of the Cordillera Vilcapampa. Yet so -near him is the edge of the forest that he is tempted to try to throw a -stone into it. In an hour a bitter wind from the mountains may drive him -to shelter or a cold fog come rolling up from the moist region below. It -is hard to believe that oppressive heat is felt in the valley just -beneath him. - -In the larger valleys the geographic contrasts are less sharp and the -transition from mountains to plain, though less spectacular, is much -more complex and scientifically interesting. The forest types -interfinger along the shady and the sunny slopes. The climate is so -varied that the forest takes on a diversified character that makes it -far more useful to man. The forest Indians and the valley planters are -in closer association. There are many islands and peninsulas of plateau -population on the valley floor. Here the zones of climate and the belts -of fertile soil have larger areas and the land therefore has greater -economic value. Much as the valley people need easier and cheaper -communication with the rest of Peru it is no exaggeration to say that -the valley products, are needed far more by the coast and plateau -peoples to make the republic self-supporting. Coca, wood, sugar, fruit, -are in such demand that their laborious and costly transportation from -the valleys to the plateau is now carried on with at least some profit -to the valley people. Improved transportation would promote travel and -friendship and supply a basis for greater political unity. - -A change in these conditions is imminent. Years ago the Peruvian -government decreed the construction of a railway from Cuzco to Santa Ana -and preliminary surveys were made but without any immediate practical -effect. By June, 1914, 12.4 miles (20 km.) had been opened to traffic. -The total length of the proposed line is 112 miles (180 km.), the gauge -is to be only 2.46 feet (75 cm.),[8] and the proposed cost several -millions of dollars. The financial problem may be solved either by a -diversion of local revenues, derived from taxes on coca and alcohol, or -by borrowed foreign capital guaranteed by local revenues. - -A shrubby vegetation is scattered along the valley from the village of -Urubamba, 12,000 feet (3,658 m.) above sea level, to the Canyon of -Torontoy. It is local and of little value. Trees appear at -Ollantaytambo, 11,000 feet (3,353 m.), and here too are more extensive -wheat and maize fields besides throngs of cacti and great patches of -wild geraniums. On our valley journey we camped in pleasant fields -flanked by steep hills whose summits each morning were tipped with snow. -Enormous alluvial fans have partly filled up the valleys and furnished -broad tracts of fertile soil. The patient farmers have cleared away the -stones on the flatter portions and built retaining walls for the smooth -fields required for irrigation. In places the lower valley slopes are -terraced in the most regular manner (Fig. 38). Some of the fans are too -steep and stony for cultivation, exposing bare tracts which wash down -and cover the fields. Here and there are stone walls built especially to -retain the rush of mud and stones that the rains bring down. Many of -them were overthrown or completely buried. Unless the stream channels on -the fans are carefully watched and effective works kept up, the labor of -years may be destroyed in a single slide from the head of a steep fan. - -Each group of fans has a population proportioned to its size and -fertility. If there are broad expanses a town like Urubamba or a great -hacienda like Huadquiña is sure to be found. One group of huge stony -fans below Urubamba (Fig. 180) has only a thin population, for the soil -is coarse and infertile and the rivers deeply intrenched. In some places -the tiny fans perched high upon the flanks of the mountains where little -tributaries burst out of steep ravines are cultivated by distant owners -who also till parts of the larger fans on the main valley floors. -Between the fans of the valley bottoms and the smooth slopes of the high -plateaus are the unoccupied lands--the steep canyon walls. Only in the -most highly favored places where a small bench or a patch of alluvium -occurs may one find even an isolated dwelling. The stair-like trails, in -some places cut in solid rock, zigzag up the rocky slopes. An ascent of -a thousand feet requires about an hour's travel with fresh beasts. The -valley people are therefore walled in. If they travel it is surely not -for pleasure. Even business trips are reduced to the smallest number. -The prosperity and happiness of the valley people are as well known -among the plateau people as is their remarkable bread. Their climate has -a combination of winter rain and winter cold with light frosts that is -as favorable for good wheat as the continuous winter cold and snow cover -of our northern Middle West. The colder grainfields of the plateau are -sowed to barley chiefly, though there is also produced some wheat. -Urubamba wheat and bread are exported in relatively large quantities, -and the market demands greater quantities than the valley can supply. -Oregon and Washington flour are imported at Cuzco, two days' muleback -journey from the wheat fields of Urubamba. - -Such are the conditions in the upper Urubamba Valley. The lower valley, -beginning at Huadquiña, is 8,000 feet (2,440 m.) above sea level and -extends down to the two-thousand-foot contour at Rosalina and to one -thousand feet (305 m.) at Pongo de Mainique. The upper and lower -sections are only a score of miles (30 km.) apart between Huadquiña and -Torontoy, but there is a difference in elevation of three thousand feet -(915 m.) at just the level where the maximum contrasts are produced. The -cold timber line is at 10,500 feet (3,200 m.).[9] Winter frosts are -common at the one place; they are absent altogether at the other. -Torontoy produces corn; Huadquiña produces sugar cane. - -These contrasts are still further emphasized by the sharp topographic -break between the two unlike portions of the valley. A few miles below -Torontoy the Urubamba plunges into a mile-deep granite canyon. The walls -are so close together that it is impossible from the canyon floor to get -into one photograph the highest and steepest walls. At one place there -is over a mile of descent in a horizontal distance of 2,000 feet. Huge -granite slabs fall off along joint planes inclined but 15° from the -vertical. The effect is stupendous. The canyon floor is littered with -coarse waste and the gradient of the river greatly steepened. There is -no cultivation. The trees cling with difficulty to patches of rock waste -or to the less-inclined slopes. There is a thin crevice vegetation that -outlines the joint pattern where seepage supplies the venturesome roots -with moisture. Man has no foothold here, save at the top of the country, -as at Machu Picchu, a typical fortress location safeguarded by the -virtually inaccessible canyon wall and connected with the main ridge -slopes only by an easily guarded narrow spur. Toward the lower end of -the canyon a little finer alluvium appears and settlement begins. -Finally, after a tumble of three thousand feet over countless rapids the -river emerges at Colpani, where an enormous mass of alluvium has been -dumped. The well-intrenched river has already cut a large part of it -away. A little farther on is Huadquiña in the Salcantay Valley, where a -tributary of the Urubamba has built up a sheet of alluvial land, bright -green with cane. From the distant peaks of Salcantay and its neighbors -well-fed streams descend to fill the irrigation channels. Thus the snow -and rock-waste of the distant mountains are turned into corn and sugar -on the valley lowlands. - -[Illustration: FIG. 44--The snow-capped Cordillera Vilcapampa north of -Yucay and the upper canyon of the Urubamba from the wheat fields near -Chinchero. In the foreground is one of the well-graded mature slopes of -Fig. 123. The crests of the mountains lie along the axis of a granite -intrusion. The extent of the snowfields is extraordinary in view of the -low latitude, 13° S.] - -[Illustration: FIG. 45--Rounded slopes due to glacial action at -Pampaconas in the Pampaconas Valley near Vilcabamba. A heavy tropical -forest extends up the Pampaconas Valley to the hill slopes in the -background. Its upper limit of growth is about 10,000 feet (3,050 m.). -The camera is pointed slightly downhill.] - -[Illustration: FIG. 46--Hacienda Huadquiña in the Salcantay Valley a -short distance above its junction with the Urubamba, elevation 8,000 -feet (2,440 m.). The cultivated fields are all planted to sugar cane. -The mountain slopes are devoted to grazing.] - -The Cordillera Vilcapampa is a climatic as well as a topographic -barrier. The southwestern aspect is dry; the northeastern aspect -forested. The gap of the canyon, it should be noticed, comes at a -critical level, for it falls just above the upper border of the zone of -maximum precipitation. The result is that though mists are driven -through the canyon by prolonged up-valley winds, they scatter on -reaching the plateau or gather high up on the flanks of the valley or -around the snowy peaks overlooking the trail between Ollantaytambo and -Urubamba. The canyon walls are drenched with rains and even some of the -lofty spurs are clothed with dense forest or scrub. - -Farther down the valley winds about irregularly, now pushed to one side -by a huge alluvial fan, now turned by some resistant spur of rock. -Between the front range of the Andes and the Cordillera Vilcapampa there -is a broad stretch of mountain country in the lee of the front range -which rises to 7,000 feet (2,134 m.) at Abra Tocate (Fig. 15), and falls -off to low hills about Rosalina. It is all very rough in that there are -nowhere any flats except for the narrow playa strips along the streams. -The dense forest adds to the difficulty of movement. In general -appearance it is very much like the rugged Cascade country of Oregon -except that the Peruvian forest is much more patchy and its trees are in -many places loaded with dense dripping moss which gives the landscape a -somber touch quite absent from most of the forests of the temperate -zone. - -The fertility of the eastern valleys of Peru--the result of a union of -favorable climate and alluvial soil--has drawn the planter into this -remote section of the country, but how can he dispose of his products? -Even today with a railway to Cuzco from the coast it is almost -impossible for him to get his sugar and cacao to the outside world.[10] -How did he manage before even this railway was built? How could the -eastern valley planter live before there were any railways at all in -Peru? In part he has solved the problem as the moonshiner of Kentucky -tried to solve it, and from cane juice makes aguardiente (brandy). The -latter is a much more valuable product than sugar, hence (1) it will -bear a higher rate of transportation, or (2) it will at the same rate of -transportation yield a greater net profit. In a remote valley where -sugar could not be exported on account of high freight rates brandy -could still be profitably exported. - -The same may be said for coca and cacao. They are condensed and valuable -products. Both require more labor than sugar but are lighter in bulk and -thus have to bear, in proportion to their value, a smaller share of the -cost of transportation. At the end of three years coca produces over a -ton of leaves per acre per year, and it can be made to produce as much -as two tons to the acre. The leaves are picked four times a year. They -are worth from eight to twelve cents gold a pound at the plantation or -sixteen cents a pound at Cuzco. An orchard of well-cultivated and -irrigated cacao trees will do even better. Once they begin to bear the -trees require relatively little care except in keeping out weeds and -brush and maintaining the water ditches. However, the pods must be -gathered at just the right time, the seeds must be raked and dried with -expert care, and after that comes the arduous labor of the grinding. -This is done by hand on an inclined plane with a heavy round stone whose -corners fit the hand. The chocolate must then be worked into cakes and -dried, or it must be sacked in heavy cowhide and sewed so as to be -practically air tight. When eight or ten years old the trees are mature -and each may then bear a thousand pounds of seed. - -[Illustration: FIG. 47--The Urubamba Valley below Paltaybamba. Harder -rocks intruded into the schists that in general compose the valley walls -here form steep scarps. It has been suggested (Davis) that such a -constricted portion of a valley be called a "shut-in." The old trail -climbed to the top of the valley and over the back of a huge spur. The -new road is virtually a tunnel blasted along the face of a cliff.] - -[Illustration: FIG 48--Coca seed beds near Quillabamba, Urubamba Valley. -The young plants are grown under shade and after attaining a height of a -foot or more are gradually accustomed to sunlight and finally -transplanted to the fields that are to become coca orchards.] - -If labor were cheap and abundant the whole trend of tropical agriculture -in the eastern valleys would be toward intensive cultivation and the -production of expensive exports. But labor is actually scarce. Every -planter must have agents who can send men down from the plateau towns. -And the planter himself must use his labor to the best advantage. -Aguardiente requires less labor than cacao and coca. The cane costs -about as much in labor the first year as the coca bush or the cacao -tree, but after that much less. The manufacture of brandy from the cane -juice requires little labor though much expensive machinery. For -chocolate, a storehouse, a grinding stone, and a rake are all that -are required. So the planter must work out his own salvation -individually. He must take account of the return upon investments in -machinery, of the number of hands he can command from among the "faena" -or free Indians, of the cost and number of imported hands from the -valley and plateau towns, and, finally, of the transportation rates -dependent upon the number of mules in the neighborhood, and distance -from the market. If in addition the labor is skilfully employed so as to -have the tasks which the various products require fall at different -periods of the year, then the planter may expect to make money upon his -time and get a return upon his initial investment in the land.[11] - -[Illustration: FIG. 49--Fig tree formerly attached to a host but now -left standing on its stilt-like aërial roots owing to the decay of the -host.] - -[Illustration: FIG. 50--A tiny rubber plant is growing under the tripod -made of yuca stems tied with banana leaves. Growing yuca is shown by the -naked stalks to the left and right of this canopy, and banana plants -fill the background. A plantation scene at Echarati.] - -The type of tropical agriculture which we have outlined is profitable -for the few planters who make up the white population of the valleys, -but it has a deplorable effect upon the Indian population. Though the -planters, one and all, complain bitterly of the drunken habits of their -laborers, they themselves put into the hands of the Indians the means of -debauchery. Practically the whole production of the eastern valleys is -consumed in Peru. What the valleys do not take is sent to the plateau, -where it is the chief cause of vicious conduct. Two-thirds of the -prisoners in the city jails are drunkards, and, to be quite plain, they -are virtually supplied with brandy by the planter, who could not -otherwise make enough money. So although the planter wants more and -better labor he is destroying the quality of the little there is, and, -if not actually reducing the quantity of it, he is at least very -certainly reducing the rate of increase. - -The difficulties of the valley planter could be at least partly overcome -in several ways. The railway will reduce transportation costs, -especially when the playas of the valleys are all cleared and the -exports increased. Moreover the eastern valleys are capable of -producing things of greater utility than brandy and coca leaves. So far -as profits are increased by cheaper transportation we may expect the -planter to produce more rather than less of brandy and coca, his two -most profitable exports, unless other products can be found that are -still more profitable. The ratio of profits on sugar and brandy will -still be the same unless the government increases the tax on brandy -until it becomes no more profitable than sugar. That is what ought to be -done for the good of the Indian population. It cannot be done safely -without offering in its place the boon of cheaper railway transportation -for the sugar crop. Furthermore, with railway improvements should go the -blessings that agricultural experiments can bestow. A government farm in -a suitable place would establish rice and cotton cultivation. Many of -the playas or lower alluvial lands along the rivers can be irrigated. -Only a small fraction of the water of the Rio Urubamba is now turned out -upon the fields. For a large part of the year the natural rainfall would -suffice to keep rice in good condition. Six tons a year are now grown on -Hacienda Sahuayaco for local use on account of the heavy rate on rice -imported on muleback from Cuzco, whither it comes by sea and by trail -from distant coastal valleys. The lowland people also need rice and it -could be sent to them down river by an easier route than that over which -their supplies now come. It should be exported to the highlands, not -imported therefrom. There are so many varieties adapted to so many kinds -of soil and climate that large amounts should be produced at fair -profits. - -The cotton plant, on the other hand, is more particular about climate -and especially the duration of dry and wet seasons; in spite of this its -requirements are all met in the Santa Ana Valley. The rainfall is -moderate and there is an abundance of dry warm soil. The plant could -make most of its growth in the wet season, and the four months of cooler -dry season with only occasional showers would favor both a bright staple -and a good picking season. More labor would be required for cotton and -rice and for the increased production of cacao than under the present -system. This would not be a real difficulty if the existing labor -supply were conserved by the practical abolition, through heavy -taxation, of the brandy that is the chief cause of the laborer's vicious -habits. This is the first step in securing the best return upon the -capital invested in a railway. Economic progress is here bound up with a -very practical morality. Colonization in the eastern valleys, of which -there have been but a few dismal attempts, will only extend the field of -influence, it will not solve the real problem of bringing the people of -the rich eastern territory of Peru into full and honorable possession of -their natural wealth. - -The value of the eastern valleys was known in Inca times, for their -stone-faced terraces and coca-drying patios may still be seen at -Echarati and on the border of the Chaupimayu Valley at Sahuayaco. -Tradition has it that here were the imperial coca lands, that such of -the forest Indians as were enslaved were obliged to work upon them, and -that the leaves were sent to Cuzco over a paved road now covered with -"montaña" or forest. The Indians still relate that at times a -mysterious, wavering, white light appears on the terraces and hills -where old treasure lies buried. Some of the Indians have gold and silver -objects which they say were dug from the floors of hill caves. There -appears to have been an early occupation of the best lands by the -Spaniards, for the long extensions down them of Quechua population upon -which the conquerors could depend no doubt combined with the special -products of the valley to draw white colonists thither.[12] General -Miller,[13] writing in 1836, mentions the villages of Incharate -(Echarati) and Sant' Ana (Santa Ana) but discourages the idea of -colonization "... since the river ... has lofty mountains on either -side of it, and is not navigable even for boats." - -In the "Itinerario de los viajes de Raimondi en el Peru"[14] there is an -interesting account of the settlement by the Rueda family of the great -estate still held by a Rueda, the wife of Señor Duque. José Rueda, in -1829, was a government deputy representative and took his pay in land, -acquiring valuable territory on which there was nothing more than a -mission. In 1830 Rueda ceded certain lands in "arriendo" (rent) and on -these were founded the haciendas Pucamoco, Sahuayaco, etc. - -Señor Gonzales, the present owner of Hacienda Sahuayaco, recently -obtained his land--a princely estate, ten miles by forty--for 12,000 -soles ($6,000). In a few years he has cleared the best tract, built -several miles of canals, hewed out houses and furniture, planted coca, -cacao, cane, coffee, rice, pepper, and cotton, and would not sell for -$50,000. Moreover, instead of being a superintendent on a neighboring -estate and keeping a shop in Cuzco, where his large family was a source -of great expense, he has become a wealthy landowner. He has educated a -son in the United States. He is importing machinery, such as a rice -thresher and a distilling plant. His son is looking forward to the -purchase of still more playa land down river. He pays a sol a day to -each laborer, securing men from Cotabambas and Abancay, where there are -many Indians, a low standard of wages, little unoccupied land, and a hot -climate, so that the immigrants do not need to become acclimatized. - -The deepest valleys in the Eastern Andes of Peru have a semi-arid -climate which brings in its train a variety of unusual geographic -relations. At first as one descends the valley the shady and sunny -slopes show sharply contrasted vegetation. - -[Illustration: FIG. 51--Robledo's mountain-side trail in the Urubamba -Valley below Rosalina.] - -[Illustration: FIG. 52--An epiphyte partly supported by a dead host at -Rosalina, elevation 2,000 feet. The epiphyte bears a striking -resemblance to a horned beast whose arched back, tightly clasped -fingers, and small eyes give it a peculiarly malignant and life-like -expression.] - -[Illustration: FIG. 53A--The smooth grassy slopes at the junction of the -Yanatili (left) and Urubamba (right) rivers near Pabellon.] - -[Illustration: FIG. 53B--Distribution of vegetation in the Urubamba -Valley near Torontoy. The patches of timber in the background occupy the -shady sides of the spurs; the sunny slopes are grass-covered; the valley -floor is filled with thickets and patches of woodland but not true -forest.] - -The one is forested, the other grass-covered. Slopes that receive the -noon and afternoon sun the greater part of the year are hottest and -therefore driest. For places in 11° south latitude the sun is well to -the north six months of the year, nearly overhead for about two months, -and to the south four months. Northwesterly aspects are therefore driest -and warmest, hence also grass-covered. In many places the line between -grass and forest is developed so sharply that it seems to be the -artificial edge of a cut-over tract. This is true especially if the -relief is steep and the hill or ridge-crests sharp.[15] - -[Illustration: FIG. 54--Climatic cross-section from the crest of the -Cordillera Vilcapampa down the eastern mountain valleys to the tropical -plains.] - -At Santa Ana this feature is developed in an amazingly clear manner, and -it is also combined with the dry timber line and with productivity in a -way I have never seen equaled elsewhere. The diagram will explain the -relation. It will be seen that the front range of the mountains is high -enough to shut off a great deal of rainfall. The lower hills and ridges -just within the front range are relatively dry. The deep valleys are -much drier. Each broad expansion of a deep valley is therefore a dry -pocket. Into it the sun pours even when all the surrounding hills and -mountains are wrapped in cloud. The greater number of hours of sunshine -hastens the rate of evaporation and still further increases the dryness. -Under the spur of much sunlight and of ample irrigation water from the -wetter hill slopes, the dry valley pockets produce huge crops of fruit -and cane. - -The influence of the local climate upon tree growth is striking. Every -few days, even in the relatively dry winter season, clouds gather about -the hills and there are local showers. The lower limit of the zone of -clouds is sharply marked and at both Santa Ana and Echarati it is -strikingly constant in elevation--about five thousand feet above sea -level. From the upper mountains the forest descends, with only small -patches of glade and prairie. At the lower edge of the zone of cloud it -stops abruptly on the warmer and drier slopes that face the afternoon -sun and continues on the moister slopes that face the forenoon sun or -that slope away from the sun. - -But this is not the only response the vegetation makes. The forest -changes in character as well as in distribution. The forest in the wet -zone is dense and the undergrowth luxuriant. In the selective slope -forest below the zone of cloud the undergrowth is commonly thin or -wanting and the trees grow in rather even-aged stands and by species. -Finally, on the valley floor and the tributary fans, there is a distinct -growth of scrub with bands of trees along the water courses. Local -tracts of coarse soil, or less rain on account of a deep "hole" in a -valley surrounded by steeper and higher mountains, or a change in the -valley trend that brings it into less free communication with the -prevailing winds, may still further increase the dryness and bring in a -true xerophytic or drought-resisting vegetation. Cacti are common all -through the Santa Ana Valley and below Sahuayaco there is a patch of -tree cacti and similar forms several square miles in extent. Still -farther down and about half-way between Sahuayaco and Pabellon are -immense tracts of grass-covered mountain slopes (Fig. 53). These extend -beyond Rosalina, the last of them terminating near Abra Tocate (Fig. -15). The sudden interruption is due to a turn in the valley giving -freer access to the up-valley winds that sweep through the pass at Pongo -de Mainique. - -[Illustration: FIG. 55--Map to show the relation of the grasslands of -the dry lower portion of the Urubamba Valley (unshaded) to the forested -lands at higher elevations (shaded). See Fig. 54 for climatic -conditions. Patches and slender tongues of woodland occur below the main -timber line and patches of grassland above it.] - -Northward from Abra Tocate (Fig. 55) the forest is practically -continuous. The break between the two vegetal regions is emphasized by a -corral for cattle and mules, the last outpost of the plateau herdsmen. -Not three miles away, on the opposite forested slope of the valley, is -the first of the Indian clearings where several families of Machigangas -spend the wet season when the lower river is in flood (Fig. 21). The -grass lands will not yield corn and coca because the soil is too thin, -infertile, and dry. The Indian farms are therefore all in the forest and -begin almost at its very edge. Here finally terminates a long peninsula -of grass-covered country. Below this point the heat and humidity rapidly -increase; the rains are heavier and more frequent; the country becomes -almost uninhabitable for stock; transportation rates double. Here is the -undisputed realm of the forest with new kinds of trees and products and -a distinctive type of forest-dwelling Indian. - -At the next low pass is the skull of an Italian who had murdered his -companions and stolen a season's picking of rubber, attempting to escape -by canoe to the lower Urubamba from the Pongo de Mainique. The -Machigangas overtook him in their swiftest dugouts, spent a night with -him, and the next morning shot him in the back and returned with their -rightful property--a harvest of rubber. For more than a decade -foreigners have been coming down from the plateau to exploit them. They -are an independent and free tribe and have simple yet correct ideas of -right and wrong. Their chief, a man of great strength of character and -one of the most likeable men I have known, told me that he placed the -skull in the pass to warn away the whites who came to rob honest -Indians. - -The Santa Ana Valley between the Canyon of Torontoy and the heavy forest -belt below Rosalina is typical of many of the eastern valleys of Peru, -both in its physical setting and in its economic and labor systems. -Westward are the outliers of the Vilcapampa range; on the east are the -smaller ranges that front the tropical lowlands. Steep valleys descend -from the higher country to join the main valley and at the mouth of -every tributary is an alluvial fan. If the alluvium is coarse and -steeply inclined there is only pasture on it or a growth of scrub. If -fine and broad it is cleared and tilled. The sugar plantations begin at -Huadquiña and end at Rosalina. Those of Santa Ana and Echarati are the -most productive. It takes eighteen months for the cane to mature in the -cooler weather at Huadquiña (8,000 feet). Less than a year is required -at Santa Ana (3,400 feet). Patches of alluvium or playas, as they are -locally called, continue as far as Santo Anato, but they are cultivated -only as far as Rosalina. The last large plantation is Pabellon; the -largest of all is Echarati. All are irrigated. In the wet months, -December to March inclusive, there is little or no irrigation. In the -four months of the dry season, June to September inclusive, there is -frequent irrigation. Since the cane matures in about ten months the -harvest seasons fall irregularly with respect to the seasons of rain. -Therefore the land is cleared and planted at irregular intervals and -labor distributed somewhat through the year. There is however a -concentration of labor toward the end of the dry season when most of the -cane is cut for grinding. - -The combined freight rate and government tax on coca, sugar, and brandy -take a large part of all that the planter can get for his crop. It is -120 miles (190 km.) from Santa Ana to Cuzco and it takes five days to -make the journey. The freight rate on coca and sugar for mule carriage, -the only kind to be had, is two cents per pound. The national tax is one -cent per pound (0.45 kg.). The coca sells for twenty cents a pound. The -cost of production is unknown, but the paid labor takes probably -one-half this amount. The planter's time, capital, and profit must come -out of the rest. On brandy there is a national tax of seven cents per -liter (0.26 gallon) and a municipal tax of two and a half cents. It -costs five cents a liter for transport to Cuzco. The total in taxes and -transport is fourteen and a half cents a liter. It sells for twenty -cents a liter. Since brandy (aguardiente), cacao (for chocolate), and -coca leaves (for cocaine) are the only precious substances which the -valleys produce it takes but a moment's inspection to see how onerous -these taxes would be to the planter if labor did not, as usual, pay the -penalty. - -Much of the labor on the plantations is free of cost to the owner and is -done by the so-called _faena_ or free Indians. These are Quechuas who -have built their cabins on the hill lands of the planters, or on the -floors of the smaller valleys. The disposition of their fields in -relation to the valley plantations is full of geographic interest. Each -plantation runs at right angles to the course of the valley. Hacienda -Sahuayaco is ten miles (16 km.) in extent down valley and forty miles -(64 km.) from end to end across the valley, and it is one of the smaller -plantations! It follows that about ten square miles lie on the valley -floor and half of this can ultimately be planted. The remaining three -hundred and ninety square miles include some mountain country with -possible stores of mineral wealth, and a great deal of "fells" -country--grassy slopes, graded though steep, excellent for pasture, with -here and there patches of arable land. But the hill country can be -cultivated only by the small farmer who supplements his supply of food -from cultivated plants like potatoes, corn, and vegetables, by keeping -cattle, mules, pigs, and poultry, and by raising coca and fruit. - -The Indian does not own any of the land he tills. He has the right -merely to live on it and to cultivate it. In return he must work a -certain number of days each year on the owner's plantation. In many -cases a small money payment is also made to the planter. The planter -prefers labor to money, for hands are scarce throughout the whole -eastern valley region. No Indian need work on the planter's land without -receiving pay directly therefor. Each also gets a small weekly allotment -of aguardiente while in the planter's employ. - -The scene every Saturday night outside the office of the _contador_ -(treasurer) of a plantation is a novel one. Several hundred Indians -gather in the dark patio in front of the office. Within the circle of -the feeble candlelight that reaches only the margin of the crowd one may -see a pack of heavy, perspiring faces. Many are pock-marked from -smallpox; here and there an eye is missing; only a few are jovial. A -name is shouted through the open door and an Indian responds. He pulls -off his cap and stands stupid and blinking, while the contador asks: - -"Faena" (free)? - -"Si, Señor," he answers. - -"Un sol" (one "sol" or fifty cents gold). The assistant hands over the -money and the man gives way to the next one on the list. If he is a -laborer in regular and constant employ he receives five soles (two fifty -gold) per week. There are interruptions now and then. A ragged, -half-drunken man has been leaning against the door post, suspiciously -impatient to receive his money. Finally his name is called. - -"Faena?" asks the contador. - -"No, Señor, cinco (five) soles." - -At that the field _superintendente_ glances at his time card and speaks -up in protest. - -"You were the man that failed to show up on Friday and Saturday. You -were drunk. You should receive nothing." - -"No, mi patrón," the man contends, "I had to visit a sick cousin in the -next valley. Oh, he was very sick, Señor," and he coughs harshly as if -he too were on the verge of prostration. The sick cousin, a faena -Indian, has been at work in another cane field on the same plantation -for two days and now calls out that he is present and has never had a -sick day in his life. Those outside laugh uproariously. The contador -throws down two soles and the drunkard is pushed back into the sweating -crowd, jostled right and left, and jeered by all his neighbors as he -slinks away grumbling. - -Another Indian seems strangely shy. He scarcely raises his voice above a -whisper. He too is a faena Indian. The contador finds fault. - -"Why didn't you come last month when I sent for you?" - -The Indian fumbles his cap, shuffles his feet, and changes his coca cud -from one bulging cheek to the other before he can answer. Then huskily: - -"I started, Señor, but my woman overtook me an hour afterward and said -that one of the ewes had dropped a lamb and needed care." - -"But your woman could have tended it!" - -"No, Señor, she is sick." - -"How, then, could she have overtaken you?" he is asked. - -"She ran only a little way and then shouted to me." - -"And what about the rest of the month?" persists the contador. - -"The other lambs came, Señor, and I should have lost them all if I had -left." - -The contador seems at the end of his complaint. The Indian promises to -work overtime. His difficulties seem at an end, but the superintendent -looks at his old record. - -"He always makes the same excuse. Last year he was three weeks late." - -So the poor shepherd is fined a sol and admonished that his lands will -be given to some one else if he does not respond more promptly to his -patron's call for work. He leaves behind him a promise and the rank -mixed smell of coca and much unwashed woolen clothing. - -It is not alone at the work that they grumble. There is malaria in the -lower valleys. Some of them return to their lofty mountain homes -prostrated with the unaccustomed heat and alternately shaking with -chills and burning with fever. Without aid they may die or become so -weakened that tuberculosis carries them off. Only their rugged strength -enables the greater number to return in good health. - -A plantation may be as large as a principality and draw its laborers -from places fifty miles away. Some of the more distant Indians need not -come to work in the canefields. Part of their flock is taken in place of -work. Or they raise horses and mules and bring in a certain number each -year to turn over to the patron. Hacienda Huadquiña (Fig. 46) takes in -all the land from the snow-covered summits of the Cordillera Vilcapampa -to the canefields of the Urubamba. Within the broad domain are half the -climates and occupations characteristic of Peru. It is difficult to see -how a thousand Indians can be held to even a mixed allegiance. It seems -impossible that word can be got to them. However the native "telegraph" -is even more perfect than that among the forest Indians. From one to the -other runs the news that they are needed in the canefields. On the trail -to and from a mountain village, in their ramblings from one high pasture -to another, within the dark walls of their stone and mud huts when they -gather for a feast or to exchange drinks of brandy and _chicha_--the -word is passed that has come up from the valleys. - -For every hundred faena Indians there are five or six regular laborers -on the plantations, so with the short term passed by the faena Indians -their number is generally half that of the total laborers at work at any -one time. They live in huts provided for them by the planter, and in the -houses of their friends among the regular laborers. Here there are -almost nightly carousals. The regular laborer comes from the city or the -valley town. The faena laborer is a small hill farmer or shepherd. They -have much to exchange in the way of clothing, food, and news. I have -frequently had their conversations interpreted for me. They ask about -the flocks and the children, who passed along the trails, what accidents -befell the people. - -"Last year," droned one to another over their chicha, "last year we lost -three lambs in a hailstorm up in the high fields near the snow. It was -very cold. My foot cracked open and, though I have bound it with wet -coca leaves every night, it will not cure," and he displays his heel, -the skin of which is like horn for hardness and covered with a crust of -dirt whose layers are a record of the weather and of the pools he has -waded for years. - -Their wanderings are the main basis of conversation. They know the -mountains better than the condors do. We hired a small boy of twelve at -Puquiura. He was to build our fires, carry water, and help drive the -mules. He crossed the Cordillera Vilcapampa on foot with us. He -scrambled down into the Apurimac canyon and up the ten thousand feet of -ascent on the other side, twisted the tails of the mules, and shouted -more vigorously then the arrieros. He was engaged to go with us to -Pasaje, where his father would return with him in a month. But he -climbed to Huascatay with us and said he wanted to see Abancay. When an -Indian whom we pressed into service dropped the instruments on the trail -and fled into the brush the boy packed them like a man. The soldier -carried a tripod on his back. The boy, not to be outdone, insisted on -carrying the plane table, and to his delight we called him a soldier -too. He went with us to Huancarama. When I paid him he smiled at the -large silver soles that I put into his hand; and when I doubled the -amount for his willingness to work his joy was unbounded. Forthwith he -set out, this time on muleback, on the return journey. The last I saw of -him he was holding his precious soles in a handkerchief and kicking his -beast with his bare heels, as light-hearted as a cavalier. Often I find -myself wondering whether he returned safely with his money. I should -very much like to see him again, for with him I associate cheerfulness -in difficult places and many a pleasant camp-fire. - - - - -CHAPTER VII - -THE GEOGRAPHIC BASIS OF REVOLUTIONS AND OF HUMAN CHARACTER IN THE -PERUVIAN ANDES - - -Human character as a spontaneous development has always been a great -factor in shaping historical events, but it is a striking fact that in -the world of our day its influence is exerted chiefly in the lowest and -highest types of humanity. The savage with his fetishes, his taboos, and -his inherent childlikeness and suspicion needs only whim or a slight -religious pretext to change his conduct. Likewise the really educated -and the thoughtful act from motives often wholly unrelated to economic -conditions or results. But the masses are deeply influenced by whatever -affects their material welfare. A purely idealistic impulse may -influence a people, but in time its effects are always displayed against -an economic background. - -There is a way whereby we may test this theory. In most places in the -world we have history in the making, and through field studies we can -get an intimate view of it. It is peculiarly the province of geography -to study the present distribution and character of men in relation to -their surroundings and these are the facts of mankind that must forever -be the chief data of economic history. It is not vain repetition to say -that this means, first of all, the study of the character of men in the -fullest sense. It means, in the second place, that a large part of the -character must be really understood. Whenever this is done there is -found a geographic basis of human character that is capable of the -clearest demonstration. It is in the geographic environment that the -material motives of humanity have struck their deepest roots. - -These conclusions might be illustrated from a hundred places in the -field of study covered in this book. Almost every chapter of Part I -contains facts of this character. I wish, however, to discuss the -subject specifically and for that purpose now turn to the conditions of -life in the remoter mountain valleys and to one or two aspects of the -revolutions that occur now and then in Peru. The last one terminated -only a few months before our arrival and it was a comparatively easy -matter to study both causes and effects. - -A caution is necessary however. It is a pity that we use the term -"revolution" to designate these little disturbances. They affect -sometimes a few, again a few hundred men. Rarely do they involve the -whole country. A good many of them are on a scale much smaller than our -big strikes. Most of them involve a loss of life smaller than that which -accompanies a city riot. They are in a sense strikes against the -government, marked by local disorders and a little violence. - -Early in 1911 the Prefect of the Department of Abancay had crowned his -long career by suppressing a revolution. He had been Subprefect at -Andahuaylas, and when the rebels got control of the city of Abancay and -destroyed some of the bridges on the principal trails, he promptly -organized a military expedition, constructed rafts, floated his small -force of men across the streams, and besieged the city. The rebel force -was driven at last to take shelter in the city jail opposite the -Prefectura. There, after the loss of half their number, they finally -surrendered. Seventy-five of them were sent to the government -penitentiary at Arequipa. Among the killed were sons from nearly half -the best families of Abancay. All of the rebels were young men. - -It would be difficult to give an adequate idea of the hatred felt by the -townspeople toward the government. Every precaution was taken to prevent -a renewal of the outbreak. Our coming was telegraphed ahead by -government agents who looked with suspicion upon a party of men, well -armed and provisioned, coming up from the Pasaje crossing of the -Apurimac, three days' journey north. The deep canyon affords shelter not -only to game, but also to fugitives, rebels, and bandits. The government -generally abandons pursuit on the upper edge of the canyon, for only a -prolonged guerilla warfare could completely subdue an armed force -scattered along its rugged walls and narrow floor. The owner of the -hacienda at Pasaje is required to keep a record of all passengers rafted -across the Apurimac, but he explains significantly that some who pass -are too hurried to write their names in his book. Once he reaches the -eastern wall of the canyon a fugitive may command a view of the entire -western wall and note the approach of pursuers. Thence eastward he has -the whole Cordillera Vilcapampa in which to hide. Pursuit is out of the -question. - -When we arrived, the venerable Prefect, a model of old-fashioned -courtesy, greeted us with the utmost cordiality. He told us of our -movements since leaving Pasaje, and laughingly explained that since we -had sent him no friendly message and had come from a rebel retreat, he -had taken it for granted that we intended to storm the town. I assured -him that we were ready to join his troops, if necessary, whereupon, with -a delightful frankness, he explained his method of keeping the situation -in hand. Several troops of cavalry and two battalions of infantry were -quartered at the government barracks. Every evening the old gentleman, a -Colonel in the Peruvian army, mounted a powerful gray horse and rode, -quite unattended, through the principal streets of the town. Several -times I walked on foot behind him, again I preceded him, stopping in -shops on the way to make trivial purchases, to find out what the people -had to say about him and the government as he rode by. One old gentleman -interested me particularly. He had only the day before called at the -Prefectura to pay his respects. Although his manner was correct there -was lacking to a noticeable degree the profusion of sentiment that is -apt to be exhibited on such an occasion. He now sat on a bench in a -shop. Both his own son and the shopkeeper's son had been slain in the -revolution. It was natural that they should be bitter. But the precise -nature of their complaint was what interested me most. One said that he -did not object to having his son lose his life for his country. But that -his country's officials should hire Indians to shoot his son seemed to -him sheer murder. Later, at Lambrama, I talked with a rebel fugitive, -and that was also his complaint. The young men drafted into the army are -Indians, or mixed, never whites. White men, and men with a small -amount of Indian blood, officer the army. When a revolutionary party -organizes it is of course made up wholly of men of white and mixed -blood, never Indians. The Indians have no more grievance against one -white party than another. Both exploit him to the limit of law and -beyond the limit of decency. He fights if he must, but never by choice. - -[Illustration: FIG. 56--The type of forest in the moister tracts of the -valley floor at Sahuayaco. In the center of the photograph is a tree -known as the "sandy matico" used in making canoes for river navigation.] - -[Illustration: FIG. 57--Arboreal cacti in the mixed forest of the dry -valley floor below Sahuayaco.] - -[Illustration: FIG. 58--Crossing the Apurimac at Pasaje. These are -mountain horses, small and wiry, with a protective coat of long hair. -They are accustomed to graze in the open without shelter during the -entire winter.] - -[Illustration: FIG. 59--Crossing the Apurimac at Pasaje. The mules are -blindfolded and pushed off the steep bank into the water and rafted -across.] - -Thus Indian troops killed the white rebels of Abancay. - -"Tell me, Señor," said the fugitive, "if you think that just. Tell me -how many Indians you think a white man worth. Would a hundred dead -Indians matter? But how replace a white man where there are so few? The -government _assassinated_ my compatriots!" - -"But," I replied, "why did you fight the government? All of you were -prosperous. Your fathers may have had a grievance against the -government, but of what had you young men to complain?" - -His reply was far from convincing. He was at first serious, but his long -abstract statements about taxes and government wastefulness trailed off -into vagueness, and he ended in a laughing mood, talking about -adventure, the restless spirit of young men, and the rich booty of -confiscated lands and property had the rebels won. He admitted that it -was a reckless game, but when I called him a mere soldier of fortune he -grew serious once more and reverted to the iniquitous taxation system of -Peru. Further inquiry made it quite clear that the ill-fated revolution -of Abancay was largely the work of idle young men looking for adventure. -It seemed a pity that their splendid physical energy could not have been -turned into useful channels. The land sorely needs engineers, -progressive ranchmen and farmers, upright officials, and a spirit of -respect for law and order. Old men talked of the unstable character of -the young men of the time, but almost all of them had themselves been -active participants in more than one revolution of earlier years. - -Every night at dinner the Prefect sent off by government telegraph a -long message to the President of the Republic on the state of the -Department, and received similar messages from the central government -about neighboring departments. These he read to us, and, curiously -enough, to the entire party, made up of army officers and townsmen. I -was surprised to find later that the company included one government -official whose son had been among the imprisoned rebels at Arequipa. We -met the young man a week later at a mountain village, a day after a -general amnesty had been declared. His escape had been made from the -prison a month before. He forcibly substituted the mess-boy's clothing -for his own, and thus passed out unnoticed. After a few days' hiding in -the city, he set out alone across the desert of Vitor, thence across the -lofty volcanic country of the Maritime Andes, through some of the most -deserted, inhospitable land in Peru, and at the end of three weeks had -reached Lambrama, near Abancay, the picture of health! - -Later I came to have a better notion of the economic basis of the -revolution, for obviously the planters and the reckless young men must -have had a mutual understanding. Somewhere the rebels had obtained the -sinews of war. The planters did not take an open part in the revolution, -but they financed it. When the rebels were crushed, the planters, at -least outwardly, welcomed the government forces. Inwardly they cursed -them for thwarting their scheme. The reasons have an interesting -geographic basis. Abancay is the center of a sugar region. Great -irrigated estates are spread out along the valley floor and the enormous -alluvial fans built into the main valley at the mouths of the tributary -streams. There is a heavy tax on sugar and on aguardiente (brandy) -manufactured from cane juice. The _hacendados_ had dreamed of lighter -taxes. The rebels offered the means of securing relief. But taxes were -not the real reason for the unrest, for many other sugar producers pay -the tax without serious complaint. Abancay is cut off from the rest of -Peru by great mountains. Toward the west, _via_ Antabamba, Cotahuasi, -and Chuquibamba, two hundred miles of trail separate its plantations -from the Pacific. Twelve days' hard riding is required to reach Lima -over the old colonial trade route. It is three days to Cuzco at the end -of the three-hundred-mile railway from the port of Mollendo. The trails -to the Atlantic rivers are impossible for trading purposes. Deep sunk in -a subtropical valley, the irrigable alluvial land of Abancay tempts the -production of sugar. - -But nature offers no easy route out of the valley. For centuries the -product has been exported at almost prohibitive cost, as in the eastern -valley of Santa Ana. The coastal valleys enjoy easy access to the sea. -Each has its own port at the valley mouth, where ocean steamers call for -cargo. Many have short railway lines from port to valley head. The -eastern valleys and Abancay have been clamoring for railways, better -trails, and wagon roads. From the public fund they get what is left. The -realization of their hopes has been delayed too long. It would be both -economic and military strategy to give them the desired railway. -Revolutions in Peru always start in one of two ways: either by a _coup_ -at Lima or an unchecked uprising in an interior province. Bolivia has -shown the way out of this difficulty. Two of her four large centers--La -Paz and Oruro--are connected by rail, and the line to Cochabamba lacks -only a few kilometres of construction.[16] To Sucre a line has been long -projected. Formerly a revolution at one of the four towns was -exceedingly difficult to stamp out. Diaz had the same double motive in -encouraging railway building in the remote desert provinces of Northern -Mexico, where nine out of ten Mexican revolutions gather headway. -Argentina has enjoyed a high degree of political unity since her railway -system was extended to Córdoba and Tucumán. The last uprising, that of -1906, took place on her remotest northeastern frontier. - -We had ample opportunity to see the hatred of the rebels. At nightfall -of September 25th we rode into the courtyard of Hacienda Auquibamba. We -had traveled under the worst possible circumstances. Our mules had been -enfeebled by hot valley work at Santa Ana and the lower Urubamba and the -cold mountain climate of the Cordillera Vilcapampa. The climb out of the -Apurimac canyon, even without packs, left them completely exhausted. We -were obliged to abandon one and actually to pull another along. It had -been a hard day in spite of a prolonged noon rest. Everywhere our -letters of introduction had won an outpouring of hospitality among a -people to whom hospitality is one of the strongest of the unwritten laws -of society. Our soldier escort rode ahead of the pack train. - -As the clatter of his mules' hoofs echoed through the dark buildings the -manager rushed out, struck a light and demanded "Who's there?" To the -soldier's cheerful "Buena noche, Señor," he sneeringly replied "Halto! -Guardia de la República, aqui hay nada para un soldado del gobierno." -Whereupon the soldier turned back to me and said we should not be able -to stop here, and coming nearer me he whispered "He is a revolutionary." -I dismounted and approached the haughty manager, who was in a really -terrible mood. Almost before I could begin to ask him for accommodations -he rattled off that there was no pasture for our beasts, no food for us, -and that we had better go on to the next hacienda. "Absolutamente nada!" -he repeated over and over again, and at first I thought him drunk. Since -it was then quite dark, with no moon, but instead heavy black clouds -over the southern half of the sky and a brisk valley wind threatening -rain, I mildly protested that we needed nothing more than shelter. Our -food boxes would supply our wants, and our mules, even without fodder, -could reach Abancay the next day. Still he stormed at the government and -would have none of us. I reminded him that his fields were filled with -sugar cane and that it was the staple forage for beasts during the part -of the year when pasture was scarce. The cane was too valuable, he said. -It was impossible to supply us. I was on the point of pitching camp -beside the trail, for it was impossible to reach the next hacienda with -an exhausted outfit. - -Just then an older man stepped into the circle of light and amiably -inquired the purpose of our journey. When it was explained, he turned to -the other and said it was unthinkable that men should be treated so -inhospitably in a strange land. Though he himself was a guest he urged -that the host should remember the laws of hospitality, whereupon the -latter at last grudgingly asked us to join him at his table and to turn -our beasts over to his servants. It was an hour or more before he would -exhibit any interest in us. When he had learned of our object in -visiting Abancay he became somewhat more friendly, though his hostility -still manifested itself. Nowhere else in South America have I seen -exhibited such boorish conduct. Nevertheless the next morning I noticed -that our mules had been well fed. He said good-by to us as if he were -glad to be rid of any one in any way connected with the hostile -government. Likewise the manager at Hacienda Pasaje held out almost -until the last before he would consent to aid us with fresh beasts. -Finally, after a day of courting I gave him a camp chair. He was so -pleased that he not only gave us beasts, but also a letter of -introduction to one of his caretakers on a farm at the top of the -cuesta. Here on a cold, stormy night we found food and fuel and the -shelter of a friendly roof. - -A by-product of the revolution, as of all revolutions in thinly settled -frontier regions, was the organization of small bands of outlaws who -infested the lonely trails, stole beasts, and left their owners robbed -and helpless far from settlements. We were cautioned to beware of them, -both by Señor Gonzales, the Prefect at Abancay, and by the Subprefect of -Antabamba. Since some of the bandits had been jailed, I could not doubt -the accuracy of the reports, but I did doubt stories of murder and of -raids by large companies of mountain bandits. As a matter of fact we -were robbed by the Governor of Antabamba, but in a way that did not -enable us to find redress in either law or lead. The story is worth -telling because it illustrates two important facts: first, the vile -so-called government that exists in some places in the really remote -sections of South America, and second, the character of the mountain -Indians. - -The urgent letter from the Prefect of Abancay to the Subprefect of -Antabamba quickly brought the latter from his distant home. When we -arrived we found him drinking with the Governor. The Subprefect was most -courteous. The Governor was good-natured, but his face exhibited a rare -combination of cruelty and vice. We were offered quarters in the -municipal building for the day or two that we were obliged to stop in -the town. The delay enabled us to study the valley to which particular -interest attaches because of its situation in the mountain zone between -the lofty pastures of the Alpine country and the irrigated fields of the -valley farmers. - -Antabamba itself lies on a smooth, high-level shoulder of the youthful -Antabamba Valley. The valley floor is narrow and rocky, and affords -little cultivable land. On the valley sides are steep descents and -narrow benches, chiefly structural in origin, over which there is -scattered a growth of scrub, sufficient to screen the deer and the bear, -and, more rarely, vagrant bands of vicuña that stray down from their -accustomed haunts in the lofty Cordillera. Three thousand feet above the -valley floor a broad shoulder begins (Fig. 60) and slopes gently up to -the bases of the true mountains that surmount the broad rolling summit -platform. Here are the great pasture lands of the Andes and their -semi-nomadic shepherds. The highest habitation in the world is located -here at 17,100 feet (5,210 m.), near a secondary pass only a few miles -from the main axis of the western chain, and but 300 feet (91 m.) below -it. - -The people of Antabamba are both shepherds and farmers. The elevation is -12,000 feet (3,658 m.), too high and exposed for anything more than -potatoes. Here is an Indian population pure-blooded, and in other -respects, too, but little altered from its original condition. There is -almost no communication with the outside world. A deep canyon fronts the -town and a lofty mountain range forms the background. - -At nightfall, one after another, the Indians came in from the field and -doffed their caps as they passed our door. Finally came the "Teniente -Gobernador," or Lieutenant Governor. He had only a slight strain of -white blood. His bearing was that of a sneak, and he confirmed this -impression by his frank disdain for his full-blooded townsmen. "How -ragged and ugly they are! You people must find them very stupid," etc. -When he found that we had little interest in his remarks, he asked us if -we had ever seen Lima. We replied that we had, whereupon he said, "Do -you see the gilded cross above the church yonder? I brought that on -muleback all the way from Lima! Think of it! These ignorant people have -never seen Lima!" His whole manner as he drew himself up and hit his -breast was intended to make us think that he was vastly superior to his -neighbors. The sequel shows that our first estimate of him was correct. - -We made our arrangements with the Governor and departed. To inspire -confidence, and at the Governor's urgent request, we had paid in advance -for our four Indians and our fresh beasts--and at double the usual -rates, for it was still winter in the Cordillera. They were to stay with -us until we reached Cotahuasi, in the next Department beyond the -continental divide, where a fresh outfit could be secured. The -Lieutenant Governor accompanied us to keep the party together. They -appeared to need it. Like our Indian peons at Lambrama the week before, -these had been taken from the village jail and represented the scum of -the town. As usual they behaved well the first day. On the second night -we reached the Alpine country where the vegetation is very scanty and -camped at the only spot that offered fuel and water. The elevation was -16,000, and here we had the lowest temperature of the whole journey, +6° -F. (-14.4° C.). Ice covered the brook near camp as soon as the sun went -down and all night long the wind blew down from the lofty Cordillera -above us, bringing flurries of snow and tormenting our unprotected -beasts. It seemed to me doubtful if our Indians would remain. I -discussed with the other members of the party the desirability of -chaining the peons to the tent pole, but this appeared so extreme a -measure that we abandoned the idea after warning the Teniente that he -must not let them escape. - -At daybreak I was alarmed at the unusual stillness about camp. A glance -showed that half our hobbled beasts had drifted back toward Antabamba -and no doubt were now miles away. The four Indian peons had left also, -and their tracks, half buried by the last snowfall, showed that they had -left hours before and that it was useless to try to overtake them. -Furthermore we were making a topographic map across the Cordillera, and, -in view of the likelihood of snow blockading the 17,600-foot (5,360 m.) -pass which we had to cross, the work ought not to be delayed. With all -these disturbing conditions to meet, and suffering acutely from mountain -sickness, I could scarcely be expected to deal gently with our official. -I drew out the sleeping Teniente and set him on his feet. To my inquiry -as to the whereabouts of the Indians that he had promised to guard, he -blinked uncertainly, and after a stupid "Quien sabe?" peered under the -cover of a sheepskin near by as if the peons had been transformed into -insects and had taken refuge under a blade of grass. I ordered him to -get breakfast and after that to take upon his back the instruments that -two men had carried up to that time, and accompany the topographer. Thus -loaded, the Lieutenant Governor of Antabamba set out on foot a little -ahead of the party. Hendriksen, the topographer, directed him to a -17,000-foot peak near camp, one of the highest stations occupied in the -traverse. When the topographer reached the summit the instruments were -there but the Teniente had fled. Hendriksen rapidly followed the tracks -down over the steep snow-covered wall of a deeply recessed cirque, but -after a half-hour's search could not get sight of the runaway, whereupon -he returned to his station and took his observations, reaching camp in -the early afternoon. - -In the meantime I had intercepted two Indians who had come from -Cotahuasi driving a llama train loaded with corn. They held a long -conversation at the top of the pass above camp and at first edged -suspiciously away. But the rough ground turned them back into the trail -and at last they came timidly along. They pretended not to understand -Spanish and protested vigorously that they had to keep on with their -llamas. I thought from the belligerent attitude of the older, which grew -rapidly more threatening as he saw that I was alone, that I was in for -trouble, but when I drew my revolver he quickly obeyed the order to sit -down to breakfast, which consisted of soup, meat, and army biscuits. I -also gave them coca and cigarettes, the two most desirable gifts one can -make to a plateau Indian, and thereupon I thought I had gained their -friendship, for they at last talked with me in broken Spanish. The older -one now explained that he must at all hazards reach Matará by nightfall, -but he would be glad to leave his son to help us. I agreed, and he set -out forthwith. The _arriero_ (muleteer) had now returned with the lost -mules and with the assistance of the Indian we soon struck camp and -loaded our mules. I cautioned the arriero to keep close watch of the -Indian, for at one time I had caught on his face an expression of hatred -more intense than I had ever seen before. The plateau Indian of South -America is usually so stupid and docile that the unexpectedly venomous -look of the man after our friendly conversation and my good treatment -alarmed me. At the last moment, and when our backs were turned, our -Indian, under the screen of the packs, slipped away from us. The arriero -called out to know where he had gone. It took us but a few moments to -gain the top of a hill that commanded the valley. Fully a half-mile away -and almost indistinguishable against the brown of the valley floor was -our late assistant, running like a deer. No mule could follow over that -broken ground at an elevation of 16,000 feet, and so he escaped. - -Fortunately that afternoon we passed a half-grown boy riding back toward -Antabamba and he promised to hand the Governor a note in Spanish, -penciled on a leaf of my traverse book. I dropped all the polite phrases -that are usually employed and wrote as follows: - - -"Señor Gobernador: - - "Your Indians have escaped, likewise the Lieutenant Governor. They - have taken two beasts. In the name of the Prefect of Abancay, I ask - you immediately to bring a fresh supply of men and animals. We - shall encamp near the first pass, three days west of Antabamba, - until you come." - -We were now without Indians to carry the instruments, which had -therefore to be strapped to the mules. Without guides we started -westward along the trail. At the next pass the topographer rode to the -summit of a bluff and asked which of the two trails I intended to -follow. Just then a solitary Indian passed and I shouted back that I -would engage the Indian and precede the party, and he could tell from my -course at the fork of the trail how to direct his map and where to gain -camp at nightfall. But the Indian refused to go with us. All my -threatening was useless and I had to force myself to beat him into -submission with my quirt. Several repetitions on the way, when he -stubbornly refused to go further, kept our guide with us until we -reached a camp site. I had offered him a week's pay for two hours' work, -and had put coca and cigarettes into his hands. When these failed I had -to resort to force. Now that he was about to leave I gave him double the -amount I had promised him. He could scarcely believe his eyes. He rushed -up to the side of my mule, and reaching around my waist embraced me and -thanked me again and again. The plateau Indian is so often waylaid in -the mountains and impressed for service, then turned loose without pay -or actually robbed, that a _promise_ to pay holds no attraction for him. -I had up to the last moment resembled this class of white. He was -astonished to find that I really meant to pay him well. - -Then he set out upon the return, faithfully delivering my note to the -topographer about the course of the trail and the position of the camp. -He had twelve miles to go to the first mountain hut, so that he could -not have traveled less than that distance to reach shelter. The next -morning a mantle of snow covered everything, yet when I pushed back the -tent flap there stood my scantily clad Indian of the night before, -shivering, with sandaled feet in the snow, saying that he had come back -to work for me! - -This camp was number thirteen out of Abancay, and here our topographer -was laid up for three days. Heretofore the elevation had had no effect -upon him, but the excessively lofty stations of the past few days and -the hard climbing had finally prostrated him. We had decided to carry -him out by the fourth day if he felt no better, but happily he recovered -sufficiently to continue the work. The delay enabled the Governor to -overtake us with a fresh outfit. On the morning of our third day in -camp he overtook us with a small escort of soldiers accompanied by the -fugitive Teniente. He said that he had come to arrest me on the charge -of maltreating an official of Peru. A few packages of cigarettes and a -handful of raisins and biscuits so stirred his gratitude that we parted -the best of friends. Moreover he provided us with four fresh beasts and -four new men, and thus equipped we set out for a rendezvous about ten -miles away. But the faithless Governor turned off the trail and sought -shelter at the huts of a company of mountain shepherds. That night his -men slept on the ground in a bitter wind just outside our camp at 17,200 -feet. They complained that they had no food. The Governor had promised -to join us with llama meat for the peons. We fed them that night and -also the next day. But we had by that time passed the crest of the -western Cordillera and were outside the province of Antabamba. The next -morning not only our four men but also our four beasts were missing. We -were stranded and sick just under the pass. To add to our distress the -surgeon, Dr. Erving, was obliged to leave us for the return home, taking -the best saddle animal and the strongest pack mule. It was impossible to -go on with the map. That morning I rode alone up a side valley until I -reached a shepherd's hut, where I could find only a broken-down, -shuffling old mule, perfectly useless for our hard work. - -Then there happened a piece of good luck that seems almost providential. -A young man came down the trail with three pack mules loaded with llama -meat. He had come from the Cotahuasi Valley the week before and knew the -trail. I persuaded him to let us hire one of his mules. In this way and -by leaving the instruments and part of our gear in the care of two -Indian youths we managed to get to Cotahuasi for rest and a new outfit. - -The young men who took charge of part of our outfit interested me very -greatly. I had never seen elsewhere so independent and clear-eyed a pair -of mountain Indians. At first they would have nothing to do with us. -They refused us permission to store our goods in their hut. To them we -were railroad engineers. They said that the railway might come and when -it did it would depopulate the country. The railway was a curse. -Natives were obliged to work for the company without pay. Their uncle -had told them of frightful abuses over at Cuzco and had warned them not -to help the railway people in any way. They had moved out here in a -remote part of the mountains so that white men could not exploit them. - -In the end, however, we got them to understand the nature of our work. -Gifts of various sorts won their friendship, and they consented to guard -the boxes we had to leave behind. Two weeks later, on his return, the -topographer found everything unmolested. - -I could not but feel that the spirit of those strong and independent -young men was much better for Peru than the cringing, subservient spirit -of most of the Indians that are serfs of the whites. The policy of the -whites has been to suppress and exploit the natives, to abuse them, and -to break their spirit. They say that it keeps down revolution; it keeps -the Indian in his place. But certainly in other respects it is bad for -the Indian and it is worse for the whites. Their brutality toward the -natives is incredible. It is not so much the white himself as the -vicious half-breed who is often allied with him as his agent. - -I shall never forget the terror of two young girls driving a donkey -before them when they came suddenly face to face with our party, and we -at the same time hastily scrambled off our beasts to get a photograph of -a magnificent view disclosed at the bend of the steep trail. They -thought we had dismounted to attack them, and fled screaming in abject -fear up the mountain side, abandoning the donkey and the pack of -potatoes which must have represented a large part of the season's -product. It is a kind of highway robbery condoned because it is only -robbing an Indian. He is considered to be lawful prey. His complaint -goes unnoticed. In the past a revolution has offered him sporadic -chances to wreak vengeance. More often it adds to his troubles by -scattering through the mountain valleys the desperate refugees or -lawless bands of marauders who kill the flocks of the mountain shepherds -and despoil their women. - -There are still considerable numbers of Indians who shun the white man -and live in the most remote corners of the mountains. I have now and -again come upon the most isolated huts, invisible from the valley -trails. They were thatched with grass; the walls were of stone; the -rafters though light must have required prodigious toil, for all timber -stops at 12,000 feet on the mountain borders. The shy fugitive who -perches his hut near the lip of a hanging valley far above the trail may -look down himself unseen as an eagle from its nest. When the owner -leaves on a journey, or to take his flock to new pastures, he buries his -pottery or hides it in almost inaccessible caves. He locks the door or -bars it, thankful if the spoiler spares rafters and thatch. - -At length we reached Cotahuasi, a town sprawled out on a terrace just -above the floor of a deep canyon (Fig. 29). Its flower gardens and -pastures are watered by a multitude of branching canals lined with low -willows. Its bright fields stretch up the lower slopes and alluvial fans -of the canyon to the limits of irrigation where the desert begins. The -fame of this charming oasis is widespread. The people of Antabamba and -Lambrama and even the officials of Abancay spoke of Cotahuasi as -practically the end of our journey. Fruits ripen and flowers blossom -every month of the year. Where we first reached the canyon floor near -Huaynacotas, elevation 11,500 feet (3,500 m.), there seemed to be acres -of rose bushes. Only the day before at an elevation of 16,800 feet -(5,120 m.) we had broken thick ice out of a mountain spring in order to -get water; now we were wading a shallow river, and grateful for the -shade along its banks. Thus we came to the town prepared to find the -people far above their plateau neighbors in character. Yet, in spite of -friendly priests and officials and courteous shopkeepers, there was a -spirit strangely out of harmony with the pleasant landscape. - -Inquiries showed that even here, where it seemed that only sylvan peace -should reign, there had recently been let loose the spirit of barbarism. -We shall turn to some of its manifestations and look at the reasons -therefor. - -In the revolution of 1911 a mob of drunken, riotous citizens gathered to -storm the Cotahuasi barracks and the jail. A full-blooded Indian -soldier, on duty at the entrance, ordered the rioters to stop and when -they paid no heed he shot the leader and scattered the crowd. The -captain thereupon ordered the soldier to Arequipa because his life was -no longer safe outside the barracks. A few months later he was assigned -to Professor Bingham's Coropuna expedition. Professor Bingham reached -the Cotahuasi Valley as I was about to leave it for the coast, and the -soldier was turned over to me so that he might leave Cotahuasi at the -earliest possible moment, for his enemies were plotting to kill him. - -He did not sleep at all the last night of his stay and had us called at -three in the morning. He told his friends that he was going to leave -with us, but that they were to announce his leaving a day later. In -addition, the Subprefect was to accompany us until daybreak so that no -harm might befall me while under the protection of a soldier who -expected to be shot from ambush. - -At four o'clock our whispered arrangements were made, we opened the -gates noiselessly, and our small cavalcade hurried through the -pitch-black streets of the town. The soldier rode ahead, his rifle -across his saddle, and directly behind him rode the Subprefect and -myself. The pack mules were in the rear. We had almost reached the end -of the street when a door opened suddenly and a shower of sparks flew -out ahead of us. Instantly the soldier struck spurs into his mule and -turned into a side street. The Subprefect drew his horse back savagely -and when the next shower of sparks flew out pushed me against the wall -and whispered: "Por Dios, quien es?" Then suddenly he shouted: "Sopla no -mas, sopla no mas" (stop blowing). - -Thereupon a shabby penitent man came to the door holding in his hand a -large tailor's flatiron. The base of it was filled with glowing charcoal -and he was about to start his day's work. The sparks were made in the -process of blowing through the iron to start the smoldering coals. We -greeted him with more than ordinary friendliness and passed on. - -At daybreak we had reached the steep western wall of the canyon where -the real ascent begins, and here the Subprefect turned back with many -_felicidades_ for the journey and threats for the soldier if he did not -look carefully after the pack train. From every angle of the zigzag -trail that climbs the "cuesta" the soldier scanned the valley road and -the trail below him. He was anxious lest news of his escape reach his -enemies who had vowed to take his life. Half the day he rode turned in -his saddle so as to see every traveler long before he was within harm's -reach. By nightfall we safely reached Salamanca, fifty miles away (Fig. -62). - -The alertness of the soldier was unusual and I quite enjoyed his close -attention to the beasts and his total abstinence, for an alert and sober -soldier on detail is a rare phenomenon in the interior of Peru. But all -Salamanca was drunk when we arrived--Governor, alcaldes, citizens. Even -the peons drank up in brandy the money that we gave them for forage and -let the beasts starve. The only sober person I saw was the white -telegraph operator from Lima. He said that he had to stay sober, for the -telegraph office--the outward sign of government--was the special object -of attack of every drink-crazed gang of rioters. They had tried to break -in a few nights before and he had fired his revolver point-blank through -the door. The town offered no shelter but the dark filthy hut of the -Gobernador and the tiny telegraph office. So I made up my bed beside -that of the operator. We shared our meals and chatted until a late hour, -he recounting the glories of Lima, to which he hoped to return at the -earliest possible moment, and cursing the squalid town of Salamanca. His -operator's keys were old, the batteries feeble, and he was in continual -anxiety lest a message could not be received. In the night he sprang out -of bed shouting frantically: - -"Estan llamando" (they are calling), only to stumble over my bed and -awaken himself and offer apologies for walking in his sleep. - -Meanwhile my soldier, having regained his courage, began drinking. It -was with great difficulty that I got started, after a day's delay, on -the trail to Chuquibamba. There his thirst quite overcame him. To -separate him from temptation it became necessary to lock him up in the -village jail. This I did repeatedly on the way to Mollendo, except -beyond Quilca, where we slept in the hot marshy valley out of reach of -drink, and where the mosquitoes kept us so busy that either eating or -drinking was almost out of the question. - -The drunken rioters of Cotahuasi and their debauched brothers at -Salamanca are chiefly natives of pure or nearly pure Indian blood. They -are a part of the great plateau population of the Peruvian Andes. Have -they degenerated to their present low state, or do they display merely -the normal condition of the plateau people? Why are they so troublesome -an element? To this as to so many questions that arise concerning the -highland population we find our answer not chiefly in government, or -religion, or inherited character, but in geography. I doubt very much if -a greater relative difference would be seen if two groups of whites were -set down, the one in the cold terrace lands of Salamanca, the other in -the warm vineyards of Aplao, in the Majes Valley. The common people of -these two towns were originally of the same race, but the lower valley -now has a white element including even most of those having the rank of -peons. Greater differences in character could scarcely be found between -the Aztecs and the Iroquois. In the warm valley there is of coarse -drunkenness, but it is far from general; there is stupidity, but the -people are as a whole alert; and finally, the climate and soil produce -grapes from which famous wines are made, they produce sugar cane, -cotton, and alfalfa, so that the whites have come in, diluted the Indian -blood, and raised the standard of life and behavior. Undoubtedly their -influence would tend to have the same general effect if they mixed in -equal numbers with the plateau groups. There is, however, a good reason -for their not doing so. - -[Illustration: FIG. 62--Salamanca, on the floor of the deep Arma Valley -(a tributary of one of the major coast valleys, the Ocoña), which is -really a canyon above this point and which, in spite of its steepness, -is thoroughly terraced and intensively cultivated up to the frost line.] - -[Illustration: FIG. 60--View across the Antabamba canyon just above -Huadquirca.] - -[Illustration: FIG. 61--Huancarama, west of Abancay, on the famous Lima -to Buenos Aires road. Note the smooth slopes in the foreground. See -Chapter XI.] - -The lofty towns of the plateau have a really wretched climate. White men -cannot live comfortably at Antabamba and Salamanca. Further, they are so -isolated that the modest comforts and the smallest luxuries of -civilization are very expensive. To pay for them requires a profitable -industry managed on a large scale and there is no such industry in the -higher valleys. The white who goes there must be satisfied to live like -an Indian. The result is easy to forecast. Outside of government -officers, only the dissolute or unsuccessful whites live in the worst -towns, like Salamanca and Antabamba. A larger valley with a slightly -milder climate and more accessible situation, like Chuquibamba, will -draw a still better grade of white citizen and in the largest of -all--Cuzco and the Titicaca basin--we find normal whites in larger -numbers, though they nowhere live in such high ratios to the Indian as -on the coast and in the lower valleys near the coast. With few -exceptions the white population of Peru is distributed in response to -favorable combinations of climate, soil, accessibility, and general -opportunities to secure a living without extreme sacrifice. - -These facts are stated in a simple way, for I wish to emphasize the -statement that the Indian population responds to quite other stimuli. -Most of the luxuries and comforts of the whites mean nothing to the -Indian. The machine-made woolens of the importers will probably never -displace his homespun llama-wool clothing. His implements are few in -number and simple in form. His tastes in food are satisfied by the few -products of his fields and his mountain flocks. Thus he has lived for -centuries and is quite content to live today. Only coca and brandy tempt -him to engage in commerce, to toil now and then in the hot valleys, and -to strive for more than the bare necessities of life. Therefore it -matters very little to him if his home town is isolated, or the -resources support but a small group of people. He is so accustomed to a -solitary existence in his ramblings with his flocks that a village of -fifty houses offers social enjoyments of a high order. Where a white -perishes for lack of society the Indian finds himself contented. -Finally, he is not subject to the white man's exploitation when he lives -in remote places. The pastures are extensive and free. The high valley -lands are apportioned by the alcalde according to ancient custom. His -life is unrestricted by anything but the common law and he need have no -care for the morrow, for the seasons here are almost as fixed as the -stars. - -Thus we have a sort of segregation of whites in the lower places where a -modern type of life is maintained and of Indians in the higher places -where they enjoy advantages that do not appeal to the whites. Above -8,000 feet the density of the white population bears a close inverse -proportion to the altitude, excepting in the case of the largest valleys -whose size brings together such numbers as to tempt the commercial and -exploiting whites to live in them. Furthermore, we should find that high -altitude, limited size, and greater isolation are everywhere closely -related to increasing immorality or decreasing character among the -whites. So to the low Indian population there is thus added the lowest -of the white population. Moreover, because it yields the largest -returns, the chief business of these whites is the sale of coca and -brandy and the downright active debauchery of the Indian. This is all -the easier for them because the isolated Indian, like the average -isolated white, has only a low and provincial standard of morality and -gets no help from such stimulation as numbers usually excite. - -For example, the Anta basin at harvest time is one of the fairest sights -in Peru. Sturdy laborers are working diligently. Their faces are bright -and happy, their skin clear, their manner eager and animated. They sing -at their work or gather about their mild _chicha_ and drink to the -patron saints of the harvest. The huts are filled with robust children; -all the yards are turned into threshing floors; and from the stubbly -hillslopes the shepherd blows shrill notes upon his barley reeds and -bamboo flute. There is drinking but there is little disorder and there -is always a sober remnant that exercises a restraining influence upon -the group. - -In the most remote places of all one may find mountain groups of a high -order of morality unaffected by the white man or actually shunning him. -Clear-eyed, thick-limbed, independent, a fine, sturdy type of man this -highland shepherd may be. But in the town he succumbs to the temptation -of drink. Some writers have tried to make him out a superior to the -plains and low valley type. He is not that. The well-regulated groups of -the lower elevations are far superior intellectually and morally in -spite of the fact that the poorly regulated groups may fall below the -highland dweller in morality. The coca-chewing highlander is a clod. -Surely, as a whole, the mixed breed of the coastal valleys is a far -worthier type, save in a few cases where a Chinese or negroid element or -both have led to local inferiority. And surely, also, that is the worst -combination which results in adding the viciousness of the inferior or -debased white to the stupidity of the highland Indian. It is here that -the effects of geography are most apparent. If the white is tempted in -large numbers because of exceptional position or resources, as at La -Paz, the rule of altitude may have an exception. And other exceptions -there are not due to physical causes, for character is practically never -a question of geography alone. There is the spiritual factor that may -illumine a strong character and through his agency turn a weak community -into a powerful one, or hold a weakened group steadfast against the -forces of disintegration. Exceptions arise from this and other causes -and yet with them all in mind the geographic factor seems predominant in -the types illustrated herewith.[17] - - - - -CHAPTER VIII - -THE COASTAL DESERT - - -To the wayfarer from the bleak mountains the warm green valleys of the -coastal desert of Peru seem like the climax of scenic beauty. The -streams are intrenched from 2,000 to 4,000 feet, and the valley walls in -some places drop 500 feet by sheer descents from one level to another. -The cultivated fields on the valley floors look like sunken gardens and -now and then one may catch the distant glint of sunlight on water. The -broad white path that winds through vineyards and cotton-fields, follows -the foot of a cliff, or fills the whole breadth of a gorge is the -waste-strewn, half-dry channel of the river. In some places almost the -whole floor is cultivated from one valley wall to the other. In other -places the fields are restricted to narrow bands between the river and -the impending cliffs of a narrow canyon. Where tributaries enter from -the desert there may be huge banks of mud or broad triangular fans -covered with raw, infertile earth. The picture is generally touched with -color--a yellow, haze-covered horizon on the bare desert above, brown -lava flows suspended on the brink of the valley, gray-brown cliffs, and -greens ranging from the dull shade of algarrobo, olive and fig trees, to -the bright shade of freshly irrigated alfalfa pastures. - -After several months' work on the cold highlands, where we rode almost -daily into hailstorms or wearisome gales, we came at length to the -border of the valley country. It will always seem to me that the weather -and the sky conspired that afternoon to reward us for the months of toil -that lay behind. And certainly there could be no happier place to -receive the reward than on the brink of the lava plateau above -Chuquibamba. There was promise of an extraordinary view in the growing -beauty of the sky, and we hurried our tired beasts forward so that the -valley below might also be included in the picture. The head of the -Majes Valley is a vast hollow bordered by cliffs hundreds of feet high, -and we reached the rim of it only a few minutes before sunset. - -[Illustration: FIG. 63--The deep fertile Majes Valley below Cantas. -Compare with Fig. 6 showing the Chili Valley at Arequipa.] - -[Illustration: FIG. 64--The Majes Valley, desert coast, western Peru. -The lighter patches on the valley floor are the gravel beds of the river -at high water. Much of the alluvial land is still uncleared.] - -I remember that we halted beside a great wooden cross and that our -guide, dismounting, walked up to the foot of it and kissed and embraced -it after the custom of the mountain folk when they reach the head of a -steep "cuesta." Also that the trail seemed to drop off like a stairway, -which indeed it was.[18] Everything else about me was completely -overshadowed by snowy mountains, colored sky, and golden-yellow desert. -One could almost forget the dark clouds that gather around the great -mass of Coropuna and the bitter winds that creep down from its glaciers -at night--it seemed so friendly and noble. Behind it lay bulky masses of -rose-tinted clouds. We had admired their gay colors only a few minutes, -when the sun dropped behind the crest of the Coast Range and the last of -the sunlight played upon the sky. It fell with such marvelously swift -changes of color upon the outermost zone of clouds as these were shifted -with the wind that the eye had scarcely time to comprehend a tint before -it was gone and one more beautiful still had taken its place. The -reflected sunlight lay warm and soft upon the white peaks of Coropuna, -and a little later the Alpine glow came out delicately clear. - -When we turned from this brilliant scene to the deep valley, we found -that it had already become so dark that its greens had turned to black, -and the valley walls, now in deep shadow, had lost half their splendor. -The color had not left the sky before the lights of Chuquibamba began to -show, and candles twinkled from the doors of a group of huts close under -the cliff. We were not long in starting the descent. Here at last were -friendly habitations and happy people. I had worked for six weeks -between 12,000 and 17,000 feet, constantly ill from mountain sickness, -and it was with no regret that I at last left the plateau and got down -to comfortable altitudes. It seemed good news when the guide told me -that there were mosquitoes in the marshes of Camaná. Any low, hot land -would have seemed like a health resort. I had been in the high country -so long that, like the Bolivian mining engineer, I wanted to get down -not only to sea level, but below it! - -[Illustration: FIG. 65--Regional diagram to show the physical relations -in the coastal desert of Peru. For location, see Fig. 20.] - -If the reader will examine Figs. 65 and 66, and the photographs that -accompany them, he may gain an idea of the more important features of -the coastal region. We have already described, in Chapters V and VII, -the character of the plateau region and its people. Therefore, we need -say little in this place of the part of the Maritime Cordillera that is -included in the figure. Its unpopulated rim (see p. 54), the -semi-nomadic herdsmen and shepherds from Chuquibamba that scour its -pastures in the moist vales about Coropuna, and the gnarled and stunted -trees at 13,000 feet (3,960 m.) which partly supply Chuquibamba with -firewood, are its most important features. A few groups of huts just -under the snowline are inhabited for only a part of the year. The -delightful valleys are too near and tempting. Even a plateau Indian -responds to the call of a dry valley, however he may shun the moist, -warm valleys on the eastern border of the Cordillera. - -[Illustration: FIG. 66--Irrigated and irrigable land of the coastal belt -of Peru. The map exhibits in a striking manner how small a part of the -whole Pacific slope is available for cultivation. Pasture grows over all -but the steepest and the highest portions of the Cordillera to the right -of (above) the dotted line. Another belt of pasture too narrow to show -on the map, grows in the fog belt on the seaward slopes of the Coast -Range. Scale, 170 miles to the inch.] - -The greater part of the coastal region is occupied by the desert. Its -outer border is the low, dry, gentle, eastward-facing slope of the Coast -Range. Its inner border is the foot of the steep descent that marks the -edge of the lava plateau. This descent is a fairly well-marked line, -here and there broken by a venturesome lava flow that extends far out -from the main plateau. Within these definite borders the desert extends -continuously northwestward for hundreds of miles along the coast of Peru -from far beyond the Chilean frontier almost to the border of Ecuador. It -is broken up by deep transverse valleys and canyons into so-called -"pampas," each of which has a separate name; thus west of Arequipa -between the Vitor and Majes valleys are the "Pampa de Vitor" and the -"Pampa de Sihuas," and south of the Vitor is the "Pampa de Islay." - -The pampa surfaces are inclined in general toward the sea. They were -built up to their present level chiefly by mountain streams before the -present deep valleys were cut, that is to say, when the land was more -than a half-mile lower. Some of their material is wind-blown and on the -walls of the valleys are alternating belts of wind-blown and water-laid -strata from one hundred to four hundred feet thick as if in past ages -long dry and long wet periods had succeeded each other. The wind has -blown sand and dust from the desert down into the valleys, but its chief -work has been to drive the lighter desert waste up partly into the -mountains and along their margins, partly so high as to carry it into -the realm of the lofty terrestrial winds, whence it falls upon surfaces -far distant from the fields of origin. There are left behind the heavier -sand which the wind rolls along on the surfaces and builds into -crescentic dunes called médanos, and the pebbles that it can sandpaper -but cannot remove bodily. Thus there are belts of dunes, belts of -irregular sand drifts, and belts of true desert "pavement" (a residual -mantle of faceted pebbles and irregular stones). - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM, DIRECTOR - -CAMANÁ QUADRANGLE - -(_Aplao_)] - -Yet another feature of the desert pampa are the "dry" valleys that join -the through-flowing streams at irregular intervals, as shown in the -accompanying regional diagram. If one follow a dry valley to its head -he will find there a set of broad and shallow tributaries. Sand drifts -may clog them and appear to indicate that water no longer flows through -them. They are often referred to by unscientific travelers as evidences -of a recent change of climate. I had once the unusual opportunity (in -the mountains of Chile) of seeing freshly fallen snow melted rapidly and -thus turned suddenly into the streams. In 1911 this happened also at San -Pedro de Atacama, northern Chile, right in the desert at 8,000 feet -(2,440 m.) elevation, and in both places the dry, sand-choked valleys -were cleaned out and definite channels reëstablished. From a large -number of facts like these we know that the dry valleys represent the -work of the infrequent rains. No desert is absolutely rainless, although -until recently it was the fashion to say so. Naturally the wind, which -works incessantly, partly offsets the work of the water. Yet the wind -can make but little impression upon the general outlines of the dry -valleys. They remain under the dominance of the irregular rains. These -come sometimes at intervals of three or four years, again at intervals -of ten to fifteen years, and some parts of the desert have probably been -rainless for a hundred years. Some specific cases are discussed in the -chapter on Climate. - -The large valleys of the desert zone have been cut by snow-fed streams -and then partly filled again so that deep waste lies on their floors and -abuts with remarkable sharpness against the bordering cliffs (Fig. 155). -Extensive flats are thus available for easy cultivation, and the -through-flowing streams furnish abundant water to the irrigating canals. -The alluvial floor begins almost at the foot of the steep western slope -of the lava plateau, but it is there stony and coarse--hence -Chuquibamba, or plain of stones (chuqui = stone; bamba = plain). Farther -down and about half-way between Chuquibamba and Aplao (Camaná -Quadrangle) it is partly covered with fresh mud and sand flows from the -bordering valley walls and the stream is intrenched two hundred feet. A -few miles above Aplao the stream emerges from its narrow gorge and -thenceforth flows on the surface of the alluvium right to the sea. -Narrow places occur between Cantas and Aplao, where there is a -projection of old and hard quartzitic rock, and again above Camaná, -where the stream cuts straight across the granite axis of the Coast -Range. Elsewhere the rock is either a softer sandstone or still -unindurated sands and gravels, as at the top of the desert series of -strata that are exposed on the valley wall. The changing width of the -valley is thus a reflection of the changing hardness of the rock. - -There is a wide range of products between Chuquibamba at 10,000 feet -(3,050 m.) at the head of the valley and Camaná near the valley mouth. -At the higher levels fruit will not grow--only alfalfa, potatoes, and -barley. A thousand feet below Chuquibamba fruit trees appear. Then -follows a barren stretch where there are mud flows and where the river -is intrenched. Below this there is a wonderful change in climate and -products. The elevation falls off 4,000 feet and the first cultivated -patches below the middle unfavorable section are covered with grape -vines. Here at 3,000 feet (900 m.) elevation above the sea begin the -famous vineyards of the Majes Valley, which support a wine industry that -dates back to the sixteenth century. Some of the huge buried earthenware -jars for curing the wine at Hacienda Cantas were made in the reign of -Philip II. - -The people of Aplao and Camaná are among the most hospitable and -energetic in Peru, as if these qualities were but the reflection of the -bounty of nature. Nowhere could I see evidences of crowding or of the -degeneracy or poverty that is so often associated with desert people. -Water is always plentiful; sometimes indeed too plentiful, for floods -and changes in the bed of the river are responsible for the loss of a -good deal of land. This abundance of water means that both the small and -the large landowners receive enough. There are none of the troublesome -official regulations, as in the poorer valleys with their inevitable -favoritism or downright graft. Yet even here the valley is not fully -occupied; at many places more land could be put under cultivation. The -Belaunde brothers at Cantas have illustrated this in their new cotton -plantation, where clearings and new canals have turned into cultivated -fields tracts long covered with brush. - -The Majes Valley sorely lacks an adequate port. Its cotton, sugar, and -wine must now be shipped to Camaná and thence to Mollendo, either by a -small bi-weekly boat, or by pack-train over the coast trail to Quilca, -where ocean steamers call. This is so roundabout a way that the planters -of the mid-valley section and the farmers of the valley head now export -their products over the desert trail from Cantas to Vitor on the -Mollendo-Arequipa railroad, whence they can be sent either to the cotton -mills or the stores of Arequipa, the chief distributing market of -southern Peru, or to the ocean port. - -The foreshore at Camaná is low and marshy where the salt water covers -the outer edge of the delta. In the hollow between two headlands a broad -alluvial plain has been formed, through which the shallow river now -discharges. Hence the natural indentation has been filled up and the -river shoaled. To these disadvantages must be added a third, the -shoaling of the sea bottom, which compels ships to anchor far off shore. -Such shoals are so rare on this dry and almost riverless coast as to be -a menace to navigation. The steamer _Tucapelle_, like all west-coast -boats, was sailing close to the unlighted shore on a very dark night in -April, 1911, when the usual fog came on. She struck the reef just off -Camaná. Half of her passengers perished in trying to get through the -tremendous surf that broke over the bar. The most practicable scheme for -the development of the port would seem to be a floating dock and tower -anchored out of reach of the surf, and connected by cable with a railway -on shore. Harbor works would be extraordinarily expensive. The valley -can support only a modest project. - -The relations of Fig. 65, representing the Camaná-Vitor region, are -typical of southern Peru, with one exception. In a few valleys the -streams are so small that but little water is ever found beyond the foot -of the mountains, as at Moquegua. In the Chili Valley is Arequipa (8,000 -feet), right at the foot of the big cones of the Maritime Cordillera -(see Fig. 6). The green valley floor narrows rapidly and cultivation -disappears but a few miles below the town. Outside the big valleys -cultivation is limited to the best spots along the foot of the Coast -Range, where tiny streams or small springs derive water from the zone of -clouds and fogs on the seaward slopes of the Coast Range. Here and there -are olive groves, a vegetable garden, or a narrow alfalfa meadow, -watered by uncertain springs that issue below the hollows of the -bordering mountains. - -[Illustration: FIG. 67--Irrigated and irrigable land in the Ica Valley -of the coastal desert of Peru.] - -[Illustration: FIG. 68--The projected canal to convey water from the -Atlantic slope to the Pacific slope of the Maritime Cordillera.[19]] - -In central and northern Peru the coastal region has aspects quite -different from those about Camaná. At some places, for example north of -Cerro Azul, the main spurs of the Cordillera extend down to the shore. -There is neither a low Coast Range nor a broad desert pampa. In such -places flat land is found only on the alluvial fans and deltas. Lima and -Callao are typical. Fig. 66, compiled from Adams's reports on the water -resources of the coastal region of Peru, shows this distinctive feature -of the central region. Beyond Salaverry extends the northern region, -where nearly all the irrigated land is found some distance back from the -shore. The farther north we go the more marked is this feature, because -the coastal belt widens. Catacaos is several miles from the sea, and -Piura is an interior place. At the extreme north, where the rains begin, -as at Tumbez, the cultivated land once more extends to the coast. - -[Illustration: FIG. 69--A stream of the intermittent type in the coastal -desert of Peru. Depth of water in the Puira River at Puira, 1905. (Bol. -de Minas del Perú, 1906, No. 45, p. 2.)] - -[Illustration: FIG. 70--A stream of the perennial type in the coastal -desert of Peru. Depth of water in the Chira River at Sullana, 1905. Data -from May to September are approximate. (Bol. de Minas del Perú, 1906, -No. 45, p. 2.)] - -These three regions contain all the fertile coastal valleys of Peru. The -larger ones are impressive--with cities, railways, ports, and land in a -high state of cultivation. But they are after all only a few hundred -square miles in extent. They contain less than a quarter of the people. -The whole Pacific slope from the crest of the Cordillera has about -15,000 square miles (38,850 sq. km.), and of this only three per cent is -irrigated valley land, as shown in Fig. 66. Moreover, only a small -additional amount may be irrigated, perhaps one half of one per cent. -Even this amount may be added not only by a better use of the water but -also by the diversion of streams and lakes from the Atlantic to the -Pacific. Figs. 67 and 68 represent such a project, in which it is -proposed to carry the water of Lake Choclococha through a canal and -tunnel under the continental divide and so to the head of the Ica -Valley. A little irrigation can be and is carried on by the use of well -water, but this will never be an important source because of the great -depth to the ground water, and the fact that it, too, depends ultimately -upon the limited rains. - -The inequality of opportunity in the various valleys of the coastal -region depends in large part also upon inequality of river discharge. -This is dependent chiefly upon the sources of the streams, whether in -snowy peaks of the main Cordillera with fairly constant run-off, or in -the western spurs where summer rains bring periodic high water. A third -type has high water during the time of greatest snow melting, combined -with summer rains, and to this class belongs the Majes Valley with its -sources in the snow-cap of Coropuna. The other two types are illustrated -by the accompanying diagrams for Puira and Chira, the former -intermittent in flow, the latter fairly constant.[20] - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM DIRECTOR - -APLAO QUADRANGLE] - - - - -CHAPTER IX - -CLIMATOLOGY OF THE PERUVIAN ANDES - - -CLIMATIC BELTS - -The noble proportions of the Peruvian Andes and their position in -tropical latitudes have given them climatic conditions of great -diversity. Moreover, their great breadth and continuously lofty summits -have distributed the various climatic types over spaces sufficiently -ample to affect large and important groups of people. When we add to -this the fact that the topographic types developed on a large scale are -distributed at varying elevations, and that upon them depend to a large -degree the chief characteristics of the soil, another great factor in -human distribution, we are prepared to see that the Peruvian Andes -afford some striking illustrations of combined climatic and topographic -control over man. - -The topographic features in their relations to the people have been -discussed in preceding chapters. We shall now examine the corresponding -effects of climate. It goes without saying that the topographic and -climatic controls cannot and need not be kept rigidly apart. Yet it -seems desirable, for all their natural interdependence, to give them -separate treatment, since the physical laws upon which their -explanations depend are of course entirely distinct. Further, there is -an independent group of human responses to detailed climatic features -that have little or no connection with either topography or soil. - -The chief climatic belts of Peru run roughly from north to south in the -direction of the main features of the topography. Between 13° and 18° -S., however, the Andes run from northwest to southeast, and in short -stretches nearly west-east, with the result that the climatic belts -likewise trend westward, a condition well illustrated on the -seventy-third meridian. Here are developed important climatic features -not found elsewhere in Peru. The trade winds are greatly modified in -direction and effects; the northward-trending valleys, so deep as to be -secluded from the trades, have floors that are nearly if not quite arid; -a restricted coastal region enjoys a heavier rainfall; and the snowline -is much more strongly canted from west to east than anywhere else in the -long belt of mountains from Patagonia to Venezuela. These exceptional -features depend, however, upon precisely the same physical laws as the -normal climatic features of the Peruvian Andes. They can, therefore, be -more easily understood after attention has been given to the larger -aspects of the climatic problem of which they form a part. - -The critical relations of trade winds, lofty mountains, and ocean -currents that give distinction to Peruvian climate are shown in Figs. 71 -to 73. From them and Fig. 74 it is clear that the two sides of the -Peruvian mountains are in sharp contrast climatically. The eastern -slopes have almost daily rains, even in the dry season, and are clothed -with forest. The western leeward slopes are so dry that at 8,000 feet -even the most drought-resisting grasses stop--only low shrubs live below -this level, and over large areas there is no vegetation whatever. An -exception is the Coast Range, not shown on these small maps, but -exhibited in the succeeding diagram. These have moderate rains on their -seaward (westerly) slopes during some years and grass and shrubby -vegetation grow between the arid coastal terraces below them and the -parched desert above. The greatest variety of climate is enjoyed by the -mountain zone. Its deeper valleys and basins descend to tropical levels; -its higher ranges and peaks are snow-covered. Between are the climates -of half the world compressed, it may be, between 6,000 and 15,000 feet -of elevation and with extremes only a day's journey apart. - -[Illustration: FIG. 71--The three chief topographic regions of Peru.] - -[Illustration: FIG. 72--The wind belts of Peru and ocean currents of -adjacent waters.] - -[Illustration: FIG. 73--The climatic belts of Peru.] - -[Illustration: FIG. 74--Belts of vegetation in Peru.] - -In the explanation of these contrasts we have to deal with relatively -simple facts and principles; but the reader who is interested chiefly in -the human aspects of the region should turn to p. 138 where the effects -of the climate on man are set forth. The ascending trades on the eastern -slopes pass successively into atmospheric levels of diminishing -pressure; hence they expand, deriving the required energy for expansion -from the heat of the air itself. The air thereby cooled has a lower -capacity for the retention of water vapor, a function of its -temperature; the colder the air the less water vapor it can take up. As -long as the actual amount of water vapor in the air is less than that -which the air can hold, no rain falls. But the cooling process tends -constantly to bring the warm, moist, ascending air currents to the limit -of their capacity for water vapor by diminishing the temperature. -Eventually the air is saturated and if the capacity diminishes still -further through diminishing temperature some of the water vapor must be -condensed from a gaseous to a liquid form and be dropped as rain. - -The air currents that rise thousands of feet per day on the eastern -slopes of the Andes pass again and again through this practically -continuous process and the eastern aspect of the mountains is kept -rain-soaked the whole year round. For the trades here have only the -rarest reversals. Generally they blow from the east day after day and -repeat a fixed or average type of weather peculiar to that part of the -tropics under their steady domination. During the southern summer, when -the day-time temperature contrasts between mountains and plains are -strongest, the force of the trade wind is greatly increased and likewise -the rapidity of the rain-making processes. Hence there is a distinct -seasonal difference in the rainfall--what we call, for want of a better -name, a "wet" and a "dry" season. - -On the western or seaward slopes of the Peruvian Andes the trade winds -descend, and the process of rain-making is reversed to one of -rain-taking. The descending air currents are compressed as they reach -lower levels where there are progressively higher atmospheric pressures. -The energy expended in the process is expressed in the air as heat, -whence the descending air gains steadily in temperature and capacity for -water vapor, and therefore is a drying wind. Thus the leeward, western -slopes of the mountains receive little rain and the lowlands on that -side are desert. - - -THE CLIMATE OF THE COAST - -A series of narrow but pronounced climatic zones coincide with the -topographic subdivisions of the western slope of the country between the -crest of the Maritime Cordillera and the Pacific Ocean. This belted -arrangement is diagrammatically shown in Fig. 75. From the zone of lofty -mountains with a well-marked summer rainy season descent is made by -lower slopes with successively less and less precipitation to the desert -strip, where rain is only known at irregular intervals of many years' -duration. Beyond lies the seaward slope of the Coast Range, more or less -constantly enveloped in fog and receiving actual rain every few years, -and below it is the very narrow band of dry coastal terraces. - -[Illustration: FIG. 75--Topographic and climatic provinces in the -coastal region of Peru. The broadest division, into the zones of regular -annual rains and of irregular rains, occurs approximately at 8,000 feet -but is locally variable. To the traveler it is always clearly defined by -the change in architecture, particularly of the house roofs. Those of -the coast are flat; those of the sierra are pitched to facilitate run -off.] - -The basic cause of the general aridity of the region has already been -noted; the peculiar circumstances giving origin to the variety in detail -can be briefly stated. They depend upon the meteorologic and -hydrographic features of the adjacent portion of the South Pacific Ocean -and upon the local topography. - -The lofty Andes interrupt the broad sweep of the southeast trades -passing over the continent from the Atlantic; and the wind circulation -of the Peruvian Coast is governed to a great degree by the high pressure -area of the South Pacific. The prevailing winds blow from the south and -the southeast, roughly paralleling the coast or, as onshore winds, -making a small angle with it. When the Pacific high pressure area is -best developed (during the southern winter), the southerly direction of -the winds is emphasized, a condition clearly shown on the Pilot Charts -of the South Pacific Ocean, issued by the U.S. Hydrographic Office. - -[Illustration: FIG. 76--Temperatures at Callao, June-September, 1912, -from observations taken by Captain A. Taylor, of Callao. Air -temperatures are shown by heavy lines; sea temperatures by light lines. -In view of the scant record for comparative land and water temperatures -along the Peruvian coast this record, short as it is, has special -interest.] - -The hydrographic feature of greatest importance is the Humboldt Current. -To its cold waters is largely due the remarkably low temperatures of the -coast.[21] In the latitude of Lima its mean surface temperature is about -10° below normal. Lima itself has a mean annual temperature 4.6° F. -below the theoretical value for that latitude, (12° S.). An accompanying -curve shows the low temperature of Callao during the winter months. From -mid-June to mid-September the mean was 61° F., and the annual mean is -only 65.6° F. (18° C.). The reduction in temperature is accompanied by a -reduction in the vapor capacity of the super-incumbent air, an effect of -which much has been made in explanation of the west-coast desert. That -it is a contributing though not exclusive factor is demonstrated in Fig. -77. Curve _A_ represents the hypothetical change of temperature on a -mountainous coast with temporary afternoon onshore winds from a _warm_ -sea. Curve _B_ represents the change of temperature if the sea be cold -(actual case of Peru). The more rapid rise of curve _B_ to the right of -X-X', the line of transition, and its higher elevation above its former -saturation level, as contrasted with _A_, indicates greater dryness -(lower relative humidity). There has been precipitation in case _A_, but -at a higher temperature, hence more water vapor remains in the air -after precipitation has ceased. Curve _B_ ultimately rises nearly to the -level of _A_, for with less water vapor in the air of case _B_ the -temperature rises more rapidly (a general law). Moreover, the higher the -temperature the greater the radiation. To summarize, curve _A_ rises -more slowly than curve _B_, (1) because of the greater amount of water -vapor it contains, which must have its temperature raised with that of -the air, and thus absorbs energy which would otherwise go to increase -the temperature of the air, and (2) because its loss of heat by -radiation is more rapid on account of its higher temperature. We -conclude from these principles and deductions that under the given -conditions a cold current intensifies, but does not cause the aridity of -the west-coast desert. - -[Illustration: FIG. 77--To show progressive lowering of saturation -temperature in a desert under the influence of the mixing process -whereby dry and cool air from aloft sinks to lower levels thus -displacing the warm surface air of the desert. The evaporated moisture -of the surface air is thus distributed through a great volume of upper -air and rain becomes increasingly rarer. Applied to deserts in general -it shows that the effect of any cosmic agent in producing climatic -change from moist to dry or dry to moist will be disproportionately -increased. The shaded areas C and C' represent the fog-covered slopes of -the Coast Range of Peru as shown in Fig. 92. X-X' represents the crest -of the Coast Range.] - -Curves _a_ and _b_ represent the rise of temperature in two contrasted -cases of warm and cold sea with the coastal mountains eliminated, so as -to simplify the principle applied to _A_ and _B_. The steeper gradient -of _b_ also represents the fact that the lower the initial temperature -the dryer will the air become in passing over the warm land. For these -two curves the transition line X-X' coincides with the crest of the -Coast Range. It will also be seen that curve _a_ is never so far from -the saturation level as curve _b_. Hence, unusual atmospheric -disturbances would result in heavier and more frequent showers. - -[Illustration: FIG. 78--Wind roses for Callao. The figures for the -earlier period (1897-1900) are drawn from data in the Boletín de la -Sociedad Geográfica de Lima, Vols. 7 and 8, 1898-1900: for the latter -period data from observations of Captain A. Taylor, of Callao. The -diameter of the circle represents the proportionate number of -observations when calm was registered.] - -[Illustration: FIG. 79--Wind roses for Mollendo. The figures are drawn -from data in Peruvian Meteorology (1892-1895), Annals of the -Astronomical Observatory of Harvard College, Vol. 30, Pt. 2, Cambridge, -Mass., 1906. Observations for an earlier period, Feb. 1889-March 1890, -(Id. Vol. 39, Pt. 1, Cambridge, Mass. 1890) record S. E. wind at 2 p. m. -97 per cent of the observation time.] - -[Illustration: FIG. 80--Wind roses for the summer and winter seasons of -the years 1911-1913. The diameter of the circle in each case shows the -proportion of calm. Figures are drawn from data in the Anuario -Meteorológico de Chile, Publications No. 3, (1911), 6 (1912) and 13 -(1913), Santiago, 1912, 1914, 1914.] - -Turning now to local factors we find on the west coast a regional -topography that favors a diurnal periodicity of air movement. The strong -slopes of the Cordillera and the Coast Range create up-slope or eastward -air gradients by day and opposite gradients by night. To this -circumstance, in combination with the low temperature of the ocean water -and the direction of the prevailing winds, is due the remarkable -development of the sea-breeze, without exception the most important -meteorological feature of the Peruvian Coast. Several graphic -representations are appended to show the dominance of the sea-breeze -(see wind roses for Callao, Mollendo, Arica, and Iquique), but interest -in the phenomenon is far from being confined to the theoretical. -Everywhere along the coast the _virazon_, as the sea-breeze is called in -contradistinction to the _terral_ or land-breeze, enters deeply into the -affairs of human life. According to its strength it aids or hinders -shipping; sailing boats may enter port on it or it may be so violent, -as, for example, it commonly is at Pisco, that cargo cannot be loaded or -unloaded during the afternoon. On the nitrate pampa of northern Chile -(20° to 25° S.) it not infrequently breaks with a roar that heralds its -coming an hour in advance. In the Majes Valley (12° S.) it blows gustily -for a half-hour and about noon (often by eleven o'clock) it settles down -to an uncomfortable gale. For an hour or two before the sea-breeze -begins the air is hot and stifling, and dust clouds hover about the -traveler. The maximum temperature is attained at this time and not -around 2.00 P. M. as is normally the case. Yet so boisterous is the noon -wind that the laborers time their siesta by it, and not by the high -temperatures of earlier hours. In the afternoon it settles down to a -steady, comfortable, and dustless wind, and by nightfall the air is once -more calm. - -[Illustration: FIG. 81--Wind roses for Iquique for the summer and winter -seasons of the years 1911-1913. The diameter of the circle in each case -shows the proportion of calm. For source of data see Fig. 80.] - -Of highest importance are the effects of the sea-breeze on -precipitation. The bold heights of the Coast Range force the nearly or -quite saturated air of the sea-wind to rise abruptly several thousand -feet, and the adiabatic cooling creates fog, cloud, and even rain on the -seaward slope of the mountains. The actual form and amount of -precipitation both here and in the interior region vary greatly, -according to local conditions and to season and also from year to year. -The coast changes height and contour from place to place. At Arica the -low coastal chain of northern Chile terminates at the Morro de Arica. -Thence northward is a stretch of open coast, with almost no rainfall and -little fog. But in the stretch of coast between Mollendo and the Majes -Valley a coastal range again becomes prominent. Fog enshrouds the hills -almost daily and practically every year there is rain somewhere along -their western aspect. - -[Illustration: FIG. 82--The wet and dry seasons of the Coast Range and -the Cordillera are complementary in time. The "wet" season of the former -occurs during the southern winter; the cloud bank on the seaward slopes -of the hills is best developed at that time and actual rains may occur.] - -[Illustration: FIG. 83--During the southern summer the seaward slopes of -the Coast Range are comparatively clear of fog. Afternoon cloudiness is -characteristic of the desert and increases eastward (compare Fig. 86), -the influence of the strong sea winds as well as that of the trades -(compare Fig. 93B) being felt on the lower slopes of the Maritime -Cordillera.] - -During the southern winter the cloud bank of the coast is best developed -and precipitation is greatest. At Lima, for instance, the clear skies of -March and April begin to be clouded in May, and the cloudiness grows -until, from late June to September, the sun is invisible for weeks at a -time. This is the period of the garua (mist) or the "tiempo de lomas," -the "season of the hills," when the moisture clothes them with verdure -and calls thither the herds of the coast valleys. - -[Illustration: FIG. 84--Cloudiness at Callao. Figures are drawn from -data in the Boletín de la Sociedad Geográfica de Lima, Vols. 7 and 8, -1898-1900. They represent the conditions at three observation hours -during the summers (Dec., Jan.) of 1897-1898, 1898-1899, 1899-1900 and -the winters (June, July) of 1898 and 1899.] - -During the southern summer on account of the greater relative difference -between the temperatures of land and water, the sea-breeze attains its -maximum strength. It then accomplishes its greatest work in the desert. -On the pampa of La Joya, for example, the sand dunes move most rapidly -in the summer. According to the Peruvian Meteorological Records of the -Harvard Astronomical Observatory the average movement of the dunes from -April to September, 1900, was 1.4 inches per day, while during the -summer months of the same year it was 2.7 inches. In close agreement are -the figures for the wind force, the record for which also shows that 95 -per cent of the winds with strength over 10 miles per hour blew from a -southerly direction. Yet during this season the coast is generally -clearest of fog and cloud. The explanation appears to lie in the -exceedingly delicate nature of the adjustments between the various -rain-making forces. The relative humidity of the air from the sea is -always high, but on the immediate coast is slightly less so in summer -than in winter. Thus in Mollendo the relative humidity during the winter -of 1895 was 81 per cent; during the summer 78 per cent. Moreover, the -temperature of the Coast Range is considerably higher in summer than in -winter, and there is a tendency to reëvaporation of any moisture that -may be blown against it. The immediate shore, indeed, may still be -cloudy as is the case at Callao, which actually has its cloudiest season -in the summer but the hills are comparatively clear. In consequence the -sea-air passes over into the desert, where the relative increase in -temperature has not been so great (compare Mollendo and La Joya in the -curve for mean monthly temperature), with much higher vapor content than -in winter. The relative humidity for the winter season at La Joya, 1895, -was 42.5 per cent; for the summer season 57 per cent. The influence of -the great barrier of the Maritime Cordillera, aided doubtless by -convectional rising, causes ascent of the comparatively humid air and -the formation of cloud. Farther eastward, as the topographic influence -is more strongly felt, the cloudiness increases until on the border -zone, about 8,000 feet in elevation, it may thicken to actual rain. Data -have been selected to demonstrate this eastern gradation of -meteorological phenomena. - -[Illustration: FIG. 85--Temperature curves for Mollendo (solid lines) -and La Joya (broken lines) April, 1894, to December, 1895, drawn from -data in Peruvian Meteorology, 1892-1895, Annals of the Astronomical -Observatory of Harvard College, Vol. 49, Pt. 2, Cambridge, Mass., 1908. -The approximation of the two curves of maximum temperature during the -winter months contrasts with the well-maintained difference in minimum -temperatures throughout the year.] - -[Illustration: FIG. 86--Mean monthly cloudiness for Mollendo (solid -line) and La Joya (broken line) from April, 1892, to December, 1895. -Mollendo, 80 feet elevation, has the maximum winter cloudiness -characteristic of the seaward slope of the Coast Range (compare Fig. 82) -while the desert station of La Joya, 4,140 feet elevation, has typical -summer cloudiness (compare Fig. 83). Figures are drawn from data in -Peruvian Meteorology, 1892-1895, Annals of the Astronomical Observatory -of Harvard College, Vol. 49, Pt. 2, Cambridge, Mass., 1908.] - -[Illustration: FIG. 87--Wind roses for La Joya for the period April, -1892, to December, 1895. Compare the strong afternoon indraught from the -south with the same phenomenon at Mollendo, Fig. 79. Figures drawn from -data in Peruvian Meteorology, 1892-1895, Annals of the Astronomical -Observatory of Harvard College, Vol. 39, Pt. 2, Cambridge, Mass., 1906.] - -At La Joya, a station on the desert northeast of Mollendo at an -elevation of 4,140 feet, cloudiness is always slight, but it increases -markedly during the summer. Caraveli, at an altitude of 5,635 feet,[22] -and near the eastern border of the pampa, exhibits a tendency toward the -climatic characteristics of the adjacent zone. Data for a camp station -out on the pampa a few leagues from the town, were collected by Mr. J. -P. Little of the staff of the Peruvian Expedition of 1912-13. They -relate to the period January to March, 1913. Wind roses for these months -show the characteristic light northwesterly winds of the early morning -hours, in sharp contrast with the strong south and southwesterly -indraught of the afternoon. The daily march of cloudiness is closely -coördinated. Quotations from Mr. Little's field notes follow: - -"In the morning there is seldom any noticeable wind. A breeze starts at -10 A. M., generally about 180° (i. e. due south), increases to 2 or 3 -velocity at noon, having veered some 25° to the southwest. It reaches a -maximum velocity of 3 to 4 at about 4.00 P. M., now coming about 225° -(i. e. southwest). By 6 P. M. the wind has died down considerably and -the evenings are entirely free from it. The wind action is about the -same every day. It is not a cold wind and, except with the fog, not a -damp one, for I have not worn a coat in it for three weeks. It has a -free unobstructed sweep across fairly level pampas.... At an interval of -every three or four days a dense fog sweeps up from the southwest, dense -enough for one to be easily lost in it. It seldom makes even a sprinkle -of rain, but carries heavy moisture and will wet a man on horseback in -10 minutes. It starts about 3 P.M. and clears away by 8.00 P. M..... -During January, rain fell in camp twice on successive days, starting at -3.00 P. M. and ceasing at 8.00 P. M. It was merely a light, steady rain, -more the outcome of a dense fog than a rain-cloud of quick approach. In -Caraveli, itself, I am told that it rains off and on all during the -month in short, light showers." This record is dated early in February -and, in later notes, that month and March are recorded rainless. - -[Illustration: FIG. 88--Wind roses for a station on the eastern border -of the Coast Desert near Caraveli during the summer (January to March) -of 1913. Compare with Fig. 87. The diameter of the circle in each case -represents the proportion of calm. Note the characteristic morning -calm.] - -Chosica (elevation 6,600 feet), one of the meteorological stations of -the Harvard Astronomical Observatory, is still nearer the border. It -also lies farther north, approximately in the latitude of Lima, and this -in part may help to explain the greater cloudiness and rainfall. The -rainfall for the year 1889-1890 was 6.14 inches, of which 3.94 fell in -February. During the winter months when the principal wind observations -were taken, over 90 per cent showed noon winds from a southerly -direction while in the early morning northerly winds were frequent. It -is also noteworthy that the "directions of the upper currents of the -atmosphere as recorded by the motion of the clouds was generally between -N. and E." Plainly we are in the border region where climatic influences -are carried over from the plateau and combine their effects with those -from Pacific sources. Arequipa, farther south, and at an altitude of -7,550 feet, resembles Chosica. For the years 1892 to 1895 its mean -rainfall was 5.4 inches. - -[Illustration: FIG. 89--Cloudiness at the desert station of Fig. 88 -(near Caraveli), for the summer (January to March) of 1913.] - -Besides the seasonal variations of precipitation there are longer -periodic variations that are of critical importance on the Coast Range. -At times of rather regular recurrence, rains that are heavy and general -fall there. Every six or eight years is said to be a period of rain, but -the rains are also said to occur sometimes at intervals of four years or -ten years. The regularity is only approximate. The years of heaviest -rain are commonly associated with an unusual frequency of winds from the -north, and an abnormal development of the warm current, El Niño, from -the Gulf of Guayaquil. Such was the case in the phenomenally rainy year -of 1891. The connection is obscure, but undoubtedly exists. - -The effects of the heavy rains are amazing and appear the more so -because of the extreme aridity of the country east of them. During the -winter the desert traveler finds the air temperature rising to -uncomfortable levels. Vegetation of any sort may be completely lacking. -As he approaches the leeward slope of the Coast Range, a cloud mantle -full of refreshing promise may be seen just peeping over the crest (Fig. -91). Long, slender cloud filaments project eastward over the margin of -the desert. They are traveling rapidly but they never advance far over -the hot wastes, for their eastern margins are constantly undergoing -evaporation. At times the top of the cloud bank rises well above the -crest of the Coast Range, and it seems to the man from the temperate -zone as if a great thunderstorm were rising in the west. But for all -their menace of wind and rain the clouds never get beyond the desert -outposts. In the summer season the aspect changes, the heavy yellow sky -of the desert displaces the murk of the coastal mountains and the -bordering sea. - -[Illustration: FIG. 90--Cloudiness at Chosica, July, 1889, to September, -1890. Chosica, a station on the Oroya railroad east of Lima, is situated -on the border region between the desert zone of the coast and the -mountain zone of yearly rains. The minimum cloudiness recorded about 11 -a. m. is shown by a broken line; the maximum cloudiness, about 7 p. m., -by a dotted line, and the mean for the 24 hours by a heavy solid line. -The curves are drawn from data in Peruvian Meteorology, 1889-1890, -Annals of the Astronomical Observatory of Harvard College, Vol. 39, Pt. -1, Cambridge, Mass., 1899.] - -It is an age-old strife renewed every year and limited to a narrow field -of action, wonderfully easy to observe. We saw it in its most striking -form at the end of the winter season in October, 1911, and for more than -a day watched the dark clouds rise ominously only to melt into nothing -where the desert holds sway. At night we camped beside a scum-coated -pool of alkali water no larger than a wash basin. It lay in a valley -that headed in the Coast Range, and carried down into the desert a mere -trickle that seeped through the gravels of the valley floor. A little -below the pool the valley cuts through a mass of granite and becomes a -steep-walled gorge. The bottom is clogged with waste, here boulders, -there masses of both coarse and fine alluvium. The water in the valley -was quite incapable of accomplishing any work except that associated -with solution and seepage, and we saw it in the wet season of an -unusually wet year. Clearly there has been a diminution in the water -supply. But time prevented us from exploring this particular valley to -its head, to see if the reduction were due to a change of climate, or -only to capture of the head-waters by the vigorous rain-fed streams that -enjoy a favorable position on the wet seaward slopes and that are -extending their watershed aggressively toward the east at the expense of -their feeble competitors in the dry belt. - -An early morning start enabled me to witness the whole series of changes -between the clear night and the murky day, and to pass in twelve hours -from the dry desert belt through the wet belt, and emerge again into the -sunlit terraces at the western foot of the Coast Range. Two hours before -daylight a fog descended from the hills and the going seemed to be -curiously heavy for the beasts. At daybreak my astonishment was great to -find that it was due to the distinctly moist sand. We were still in the -desert. There was not a sign of a bush or a blade of grass. Still, the -surface layer, from a half inch to an inch thick, was really wet. The -fog that overhung the trail lifted just before sunrise, and at the first -touch of the sun melted away as swiftly as it had come. With it went the -surface moisture and an hour after sunrise the dust was once more rising -in clouds around us. - -We had no more than broken camp that morning when a merchant with a -pack-train passed us, and shouted above the bells of the leading animals -that we ought to hurry or we should get caught in the rain at the pass. -My guide, who, like many of his kind, had never before been over the -route he pretended to know, asked him in heaven's name what drink in -distant Camaná whence he had come produced such astonishing effects as -to make a man talk about rain in a parched desert. We all fell to -laughing and at our banter the stranger stopped his pack-train and -earnestly urged us to hurry, for, he said, the rains beyond the pass -were exceptionally heavy this year. We rode on in a doubtful state of -mind. I had heard about the rains, but I could not believe that they -fell in real showers! - -About noon the cloud bank darkened and overhung the border of the -desert. Still the sky above us was clear. Then happened what I can yet -scarcely believe. We rode into the head of a tiny valley that had cut -right across the coast chain. A wisp of cloud, an outlier of the main -bank, lay directly ahead of us. There were grass and bushes not a -half-mile below the bare dry spot on which we stood. We were riding down -toward them when of a sudden the wind freshened and the cloud wisp -enveloped us, shutting out the view, and ten minutes later the moisture -had gathered in little beads on the manes of our beasts and the trail -became slippery. In a half-hour it was raining and in an hour we were in -the midst of a heavy downpour. We stopped and pastured our famished -beasts in luxuriant clover. While they gorged themselves a herd of -cattle drifted along, and a startled band of burros that suddenly -confronted our beasts scampered out of sight in the heavy mist. Later we -passed a herdsman's hut and long before we reached him he shouted to us -to alter our course, for just ahead the old trail was wet and -treacherous at this time of year. The warning came too late. Several of -our beasts lost their footing and half rolled, half slid, down hill. One -turned completely over, pack and all, and lay in the soft mud calmly -taking advantage of the delay to pluck a few additional mouthfuls of -grass. We were glad to reach firmer ground on the other side of the -valley. - -The herdsmen were a hospitable lot. They had come from Camaná and rarely -saw travelers. Their single-roomed hut was mired so deeply that one -found it hard to decide whether to take shelter from the rain inside or -escape the mud by standing in the rain outside. They made a little -so-called cheese, rounded up and counted the cattle on clear days, -drove them to the springs from time to time, and talked incessantly of -the wretched rains in the hills and the delights of dry Camaná down on -the coast. We could not believe that only some hours' traveling -separated two localities so wholly unlike. - -The heavy showers and luxuriant pastures of the wet years and the light -local rains of the dry years endow the Coast Range with many peculiar -geographic qualities. The heavy rains provide the desert people at the -foot of the mountains such a wealth of pasture for their burdensome -stock as many oases dwellers possess only in their dreams. From near and -far cattle are driven to the wet hill meadows. Some are even brought in -from distant valleys by sea, yet only a very small part of the rich -pastures can be used. It is safe to say that they could comfortably -support ten times the number of cattle, mules, and burros that actually -graze upon them. The grass would be cut for export if the weather were -not so continually wet and if there were not so great a mixture of -weeds, flowers, and shrubs. - -Then come the dry years. The surplus stock is sold, and what remains is -always maintained at great expense. In 1907 I saw stock grazing in a -small patch of dried vegetation back of Mollendo, although they had to -be driven several miles to water. They looked as if they were surviving -with the greatest difficulty and their restless search for pasture was -like the search of a desperate hunter of game. In 1911 the same tract -was quite devoid of grass, and except for the contour-like trails that -completely covered the hills no one would even guess that this had -formerly been a cattle range. The same year, but five months later, a -carpet of grass, bathed in heavy mist, covered the soil; a trickle of -water had collected in pools on the valley floor; several happy families -from the town had laid out a prosperous-looking garden; there were -romping children who showed me where to pick up the trail to the port; -on every hand was life and activity because the rains had returned -bringing plenty in their train. I asked a native how often he was -prosperous. - -"Segun el temporal y la Providencia" (according to the weather and to -Providence), he replied, as he pointed significantly to the pretty green -hills crowned with gray mist. - -It, therefore, seems fortunate that the Coast Range is so placed as to -intercept and concentrate a part of the moisture that the sea-winds -carry, and doubly fortunate that its location is but a few miles from -the coast, thereby giving temporary relief to the relatively crowded -people of the lower irrigated valleys and the towns. The wet years -formerly developed a crop of prospectors. Pack animals are cheaper when -there is good pasture and they are also easier to maintain. So when the -rains came the hopeful pick-and-shovel amateurs began to emigrate from -the towns to search for ore among the discolored bands of rock intruded -into the granite masses of the coastal hills. However, the most likely -spots have been so thoroughly and so unsuccessfully prospected for many -years that there is no longer any interest in the "mines." - -Transportation rates are still most intimately related to the rains. My -guide had two prices--a high price if I proposed to enter a town at -night and thus require him to buy expensive forage; a low price if I -camped in the hills and reached the town in time for him to return to -the hills with his animals. Inquiry showed that this was the regular -custom. I also learned that in packing goods from one part of the coast -to another forage must be carried in dry years or the beasts required to -do without. In wet years by a very slight detour the packer has his -beasts in good pasture that is free for all. The merchant who dispatches -the goods may find his charges nearly doubled in extremely dry years. -Goods are more expensive and there is a decreased consumption. The -effects of the rains are thus transmitted from one to another, until at -last nearly all the members of a community are bearing a share of the -burdens imposed by drought. As always there are a few who prosper in -spite of the ill wind. If the pastures fail, live stock _must_ be sold -and the dealers ship south to the nitrate ports or north to the large -coast towns of Peru, where there is always a demand. Their business is -most active when it is dry or rather at the beginning, of the dry -period. Also if transport by land routes becomes too expensive the small -traders turn to the sea routes and the carriers have an increased -business. But so far as I have been able to learn, dry years favor only -a few scattered individuals. - -To the traveler on the west coast it is a source of constant surprise -that the sky is so often overcast and the ports hidden by fog, while on -every hand there are clear evidences of extreme aridity. Likewise it is -often inquired why the sunsets there should be often so superlatively -beautiful during the winter months when the coast is fog bound. Why a -desert when the air is so humid? Why striking sunsets when so many of -the days are marked by dull skies? As we have seen in the first part of -this chapter, the big desert tracts lie east of the Coast Range, and -there, excepting slight summer cloudiness, cloudless skies are the rule. -The desert just back of the coast is in many parts of Peru only a narrow -fringe of dry marine terraces quite unlike the real desert in type of -weather and in resources. The fog bank overhanging it forms over the -Humboldt Current which lies off shore; it drifts landward with the -onshore wind; it forms over the upwelling cold water between the current -and the shore; it gathers on the seaward slopes of the coastal hills as -the inflowing air ascends them in its journey eastward. Sometimes it -lies on the surface of the land and the water; more frequently it is -some distance above them. On many parts of the coast its characteristic -position is from 2,000 to 4,000 feet above sea level, descending at -night nearly or quite to the surface, ascending by day and sometimes all -but disappearing except as rain-clouds on the hills.[23] Upon the local -behavior of the fog bank depends in large measure the local climate. A -general description of the coastal climate will have many exceptions. -The physical principles involved are, however, the same everywhere. I -take for discussion therefore the case illustrated by Fig. 92, since -this also displays with reasonable fidelity the conditions along that -part of the Peruvian coast between Camaná and Mollendo which lies in the -field of work of the Yale Peruvian Expedition of 1911. - -Three typical positions of the fog bank are shown in the figure, and a -fourth--that in which the bank extends indefinitely westward--may be -supplied by the imagination. - -If the cloud bank be limited to _C_ only the early morning hours at the -port are cloudy. If it extend to _B_ the sun is obscured until midday. -If it reach as far west as _A_ only a few late afternoon hours are -sunny. Once in a while there is a sudden splash of rain--a few drops -which astonish the traveler who looks out upon a parched landscape. The -smaller drops are evaporated before reaching the earth. In spite of the -ever-present threat of rain the coast is extremely arid. Though the -vegetation appears to be dried and burned up, the air is humid and for -months the sky may be overcast most of the time. So nicely are the -rain-making conditions balanced that if one of our ordinary low-pressure -areas, or so-called cyclonic storms, from the temperate zone were set in -motion along the foot of the mountains, the resulting deluge would -immediately lay the coast in ruins. The cane-thatched, mud-walled huts -and houses would crumble in the heavy rain like a child's sand pile -before a rising sea; the alluvial valley land would be coated with -infertile gravel; and mighty rivers of sand, now delicately poised on -arid slopes, would inundate large tracts of fertile soil. - -[Illustration: FIG. 91--Looking down the canyon of the Majes River to -the edge of the cloud bank formed against the Coast Range back of -Camaná.] - -[Illustration: FIG. 92--Topographic and climatic cross-section to show -the varying positions of the cloud bank on the coast of Peru, the dry -terrace region, and the types of stream profiles in the various belts.] - -If the fog and cloud bank extend westward indefinitely, the entire day -may be overcast or the sun appear for a few moments only through -occasional rifts. Generally, also, it will make an appearance just -before sunset, its red disk completely filling the narrow space between -the under surface of the clouds and the water. I have repeatedly seen -the ship's passengers and even the crew leave the dinner table and -collect in wondering groups about the port-holes and doorways the better -to see the marvelous play of colors between sky and sea. It is -impossible not to be profoundly moved by so majestic a scene. A long -resplendent path of light upon the water is reflected in the clouds. -Each cloud margin is tinged with red and, as the sun sinks, the long -parallel bands of light are shortened westward, changing in color as -they go, until at last the full glory of the sunset is concentrated in a -blazing arc of reds, yellows, and purples, that to most people quite -atones for the dull gray day and its humid air. - -At times the clouds are broken up by the winds and scattered -helter-skelter through the west. A few of them may stray into the path -of the sun temporarily to hide it and to reflect its primary colors when -the sun reappears. From the main cloud masses there reach out slender -wind-blown streamers, each one delicately lighted as the sun's rays -filter through its minute water particles. Many streamers are visible -for only a short distance, but when the sun catches them their filmy -invisible fingers become delicate bands of light, some of which rapidly -grow out almost to the dome of the sky. Slowly they retreat and again -disappear as the rays of the sun are gradually shut off by the upturning -curve of the earth. - -The unequal distribution of precipitation in the climatic zones of -western Peru has important hydrographic consequences. These will now be -considered. In the preceding figure four types of stream profiles are -displayed and each has its particular relation to the cloud bank. Stream -1 is formed wholly upon the coastal terraces beneath the cloud bank. It -came into existence only after the uplift of the earth's crust that -brought the wave-cut platforms above sea level. It is extremely youthful -and on account first of the small seepage at its headquarters--it is -elsewhere wholly without a tributary water supply--and, second, of the -resistant granite that occurs along this part of the coast, it has very -steep and irregular walls and an ungraded floor. Many of these -"quebradas" are difficult to cross. A few of them have fences built -across their floors to prevent the escape of cattle and burros that -wander down from the grassy hills into the desert zone. Others are -partitioned off into corrals by stone fences, the steep walls of the -gorge preventing the escape of the cattle. To these are driven the -market cattle, or mules and burros that are required for relays along -the shore trail. - -Stream 2 heads in the belt of rains. Furthermore it is a much older -stream than 1, since it dates back to the time when the Coast Range was -first formed. It has ample tributary slopes and a large number of small -valleys. A trickle of water flows down to become lost in the alluvium of -the lower part of the valley or to reappear in scattered springs. Where -springs and seepage occur together, an olive grove or a garden marks the -spot, a corral or two and a mud or stone or reed hut is near by, and -there is a tiny oasis. Some of these dots of verdure become so dry -during a prolonged drought that the people, long-established, move away. -To others the people return periodically. Still others support permanent -settlements. - -Stream 3 has still greater age. Its only competitors are the feeble, -almost negligible, streams that at long intervals flow east toward the -dry zone. Hence it has cut back until it now heads in the desert. Its -widely branched tributaries gather moisture from large tracts. There is -running water in the valley floor even down in the terrace zone. At -least there are many dependable springs and the permanent homes that -they always encourage. A valley of this type is always marked by a -well-defined trail that leads from settlement to settlement and eastward -over the "pass" to the desert and the Andean towns. - -Stream 4 is a so-called "antecedent" stream. It existed before the Coast -Range was uplifted and cut its channel downward as the mountains rose in -its path. The stretch where it crosses the mountains may be a canyon -with a narrow, rocky, and uncultivable floor, so that the valley trails -rise to a pass like that at the head of stream 3, and descend again to -the settlements at the mouth of 4. There is in this last type an -abundance of water, for the sources of the stream are in the zone of -permanent snows and frequent winter rains of the lofty Cordillera of the -Andes. The settlements along this stream are continuous, except where -shut-ins occur--narrow, rocky defiles caused by more resistant rock -masses in the path of the stream. Here and there are villages. The -streams have fish. When the water rises the river may be unfordable and -people on opposite sides must resort to boats or rafts.[24] - - -EASTERN BORDER CLIMATES - -On windward mountain slopes there is always a belt of maximum -precipitation whose elevation and width vary with the strength of the -wind, with the temperature, and with the topography. A strong and -constant wind will produce a much more marked concentration of the -rainfall. The belt is at a low elevation in high latitudes and at a high -elevation in low latitudes, with many irregularities of position -dependent upon the local and especially the minimum winter temperature. -The topographic controls are important, since the rain-compelling -elevation may scatter widely the localities of maximum precipitation or -concentrate them within extremely narrow limits. The human effects of -these climatic conditions are manifold. Wherever the heaviest rains are, -there, too, as a rule, are the densest forests and often the most -valuable kinds of trees. If the general climate be favorable and the -region lie near dense and advanced populations, exploitation of the -forest and progress of the people will go hand in hand. If the region be -remote and some or all of the people in a primitive state, the forest -may hinder communication and retard development, especially if it lie in -a hot zone where the natural growth of population is slow.... These are -some of the considerations we shall keep in mind while investigating the -climate of the eastern border of the Peruvian Andes. - -[Illustration: FIG. 93A--Cloud types and rainfall belts on the eastern -border of the Peruvian Andes in the dry season, southern winter. The -zone of maximum rainfall extends approximately from 4,000 to 10,000 feet -elevation.] - -[Illustration: FIG. 93B--Cloud types and rainfall belts on the eastern -border of the Peruvian Andes in the wet season, southern summer.] - -The belt of maximum precipitation on the eastern border of the Andean -Cordillera in Peru lies between 4,000 and 10,000 feet. Judging by the -temporary records of the expedition and especially by the types of -forest growth, the heaviest rains occur around 8,000 feet. It is between -these elevations that the densest part of the Peruvian _montaña_ -(forest) is found. The cold timber line is at 10,500 feet with -exceptional extensions of a few species to 12,500 feet. In basins or -deep secluded valleys near the mountain border, a dry timber line occurs -at 3,000 feet with many variations in elevation due to the variable -declivity and exposure of the slopes and degree of seclusion of the -valleys. Elsewhere, the mountain forest passes without a break into the -plains forest with change in type but with little change in density. The -procumbent and suppressed trees of the cold timber line in regions of -heavy winter snows are here absent, for the snows rarely reach below -14,000 feet and even at that elevation they are only light and -temporary. The line of perpetual snow is at 15,000 feet. This permanent -gap of several thousand feet vertical elevation between the zone of snow -and the zone of forest permits the full extension of many pioneer forest -species, which is to say, there is an irregular development of the cold -timber line. It also permits the full use of the pasture belt above the -timber (Fig. 97), hence permanent habitations exist but little below the -snowline and a group of distinctive high-mountain folk enjoys a wide -distribution. There is a seasonal migration here, but it is not -wholesale; there are pastures snow-covered in the southern winter, but, -instead of the complete winter burial of the Alpine meadows of our -western mountains, we have here only a buried upper fringe. All the rest -of the pasture belt is open for stock the year round. - -This climatic distinction between the lofty grazing lands of the tropics -and those of the temperate zones is far-reaching. Our mountain forests -are not utilized from above but from below. Furthermore, the chief ways -of communication lead around our forests, or, if through them, only for -the purpose of putting one population group in closer touch with -another. In the Peruvian Andes the largest population groups live above -the forest, not below it or within it. It must be and is exploited from -above. - -Hence railways to the eastern valleys of Peru have two chief objects, -(1) to get the plantation product to the dense populations above the -forest and (2) to bring timber from the _montaña_ to the treeless -plateau. The mountain prospector is always near a habitation; the rubber -prospector goes down into the forested valleys and plains far from -habitations. The forest separates the navigable streams from the chief -towns of the plateau; it does not lead down to rich and densely -populated valley floors. - -Students in eastern Peru should find it a little difficult to understand -poetical allusions to silent and lonely highlands in contrast to the -busy life of the valleys. To them Shelley's description of the view from -the Euganean Hills of northern Italy, - - "Beneath is spread like a green sea - The waveless plain of Lombardy, ... - Islanded by cities fair," - -might well seem to refer to a world that is upside down. - -There is much variation in the forest types between the mountains and -the plains. At the top of the forest zone the warm sunny slopes have a -forest cover; the shady slopes are treeless. At the lower edge of the -grassland, only the shady slopes are forested (Fig. 53B). Cacti of -arboreal size and form grow on the lofty mountains far above the limits -of the true forest; they also appear at 3,000 feet in modified form, -large, rank, soft-spined, and in dense stands on the semi-arid valley -floors below the dry timber line. Large tracts between 8,000 and 10,000 -feet are covered with a forest growth distributed by species--here a -dense stand of one type of tree, there another. This is the most -accessible part of the Peruvian forest and along the larger valleys it -is utilized to some extent. The number of species is more limited, -however, and the best timber trees are lower down. Though often referred -to as jungle, the lowlier growths at the upper edge of the forest zone -have no resemblance to the true jungle that crowds the lowland forest. -They are merely an undergrowth, generally open, though in some places -dense. They are nowhere more dense than many examples from New England -or the West. - -Where deep valleys occur near the border of the mountains there is a -semi-arid climate below and a wet climate above, with a correspondingly -greater number of species within short distances of each other. This is -a far more varied forest than at the upper edge of the timber zone or -down on the monotonous plains. It has a higher intrinsic value than any -other. That part of it between the Pongo and Yavero (1,200 to 4,000 -feet) is very beautiful, with little undergrowth except a light -ground-cover of ferns. The trees are from 40 to 100 feet in height with -an average diameter of about 15 inches. It would yield from 3,000 to -5,000 board feet per acre exclusive of the palms. There are very few -vines suspended from the forest crown and the trunks run clear from 30 -to 60 feet above the ground. Were there plenty of labor and a good -transportation line, these stands would have high economic value. Among -the most noteworthy trees are the soft white cedar, strong and light; -the amarillo and the sumbayllo, very durable in water; the black nogal, -and the black balsam, straight and easy to work; the heavy yunquero, -which turns pink when dry; the chunta or black palm, so hard and -straight and easy to split that wooden nails are made from it; and the -rarer sandy matico, highly prized for dug-out canoes. Also from the -chunta palm, hollow except for a few central fibers, easily removed, -pipes are made to convey water. The cocobolo has a rich brown color and -a glossy surface and is very rare, hence is much sought after for use in -furniture making. Most of these woods take a brilliant polish and -exhibit a richness and depth of color and a beauty of grain that are -rare among our northern woods. - -[Illustration: FIG. 94--Cloud belt at 11,000 feet in the Apurimac Canyon -near Incahuasi. For a regional diagram and a climatic cross-section see -Figs. 32 and 33.] - -[Illustration: FIG. 95--The tropical forest near Pabellon on the slopes -of the Urubamba Valley. Elevation 3,000 feet (915 m.).] - -The plains forest northeast of the mountains is in the zone of moderate -rainfall where there is one long dry season and one long wet season. -When it is dry the daytime temperatures rise rapidly to such high levels -that the relative humidity of the air falls below 50 per cent (Fig. -110). The effect on the vegetation is so marked that many plants pass -into a distinctly wilted condition. On clear days the rapid fall in the -relative humidity is astonishing. By contrast the air on the mountain -border heats more slowly and has a higher relative humidity, because -clouds form almost constantly in the ascending air currents and reflect -and absorb a large part of the heat of the sun's rays. It is striking to -find large tracts of cane and bamboo on the sand bars and on wet shady -hillslopes in the slope belt, and to pass out of them in going to the -plains with which we generally associate a swamp vegetation. They exist -on the plains, but only in favored, that is to say wet, spots. Larger -and more typical tracts grow farther north where the heavier rains of -the Amazon basin fall. - -The floods of the wet tropical season also have a restricting influence -upon the tropical forest. They deliver such vast quantities of water to -the low-gradient lowland streams that the plains rivers double, even -treble, their width and huge pools and even temporary lakes form in the -shallow depressions back of the natural levees. Of trees in the flooded -areas there are only those few species that can grow standing in water -several months each year. There are also cane and bamboo, ferns in -unlimited numbers, and a dense growth of jungle. These are the haunts of -the peccary, the red forest deer, and the jungle cat. Except along the -narrow and tortuous animal trails the country is quite impassable. Thus -for the sturdiest and most useful forest growth the one-wet-one-dry -season zone of the plains has alternately too much and too little water. -The rubber tree is most tolerant toward these conditions. Some of the -best stands of rubber trees in Amazonia are in the southwestern part of -the basin of eastern Peru and Bolivia, where there is the most typical -development of the habitat marked by the seasonal alternation of floods -and high temperatures. - -When tropical agriculture is extended to the plains the long dry season -will be found greatly to favor it. The southwestern quadrant of the -Amazon basin, above referred to, is the best agricultural area within -it. The northern limits of the tract are only a little beyond the Pongo. -Thence northward the climate becomes wetter. Indeed the best tracts of -all extend from Bolivia only a little way into southeastern Peru, and -are coincident with the patchy grasslands that are there interspersed -with belts of woodland and forest. Sugar-cane is favored by a climate -that permits rapid growth with a heavy rainfall and a dry season is -required for quality and for the harvest. Rice and a multitude of -vegetable crops are also well suited to this type of climate. Even corn -can be grown in large quantities. - -At the present time tropical agriculture is almost wholly confined to -the mountain valleys. The reasons are not wholly climatic, as the above -enumeration of the advantages of the plains suggests. The consuming -centers are on the plateau toward the west and limitation to mule pack -transport always makes distance in a rough country a very serious -problem. The valleys combine with the advantage of a short haul a -climate astonishingly like the one just described. In fact it is even -more extreme in its seasonal contrasts. The explanation is dependent -upon precisely the same principles we have hitherto employed. The front -range of the Andes and the course of the Urubamba run parallel for some -distance. Further, the front range is in many places somewhat higher -than the mountain spurs and knobs directly behind it. Even when these -relations are reversed the front range still acts as a barrier to the -rains for all the deep valleys behind it whose courses are not directly -toward the plains. Thus, one of the largest valleys in Peru, the -Urubamba, drops to 3,400 feet at Santa Ana and to 2,000 feet at -Rosalina, well within the eastern scarp of the Andes. The mountains -immediately about it are from 6,000 to 10,000 feet high. The result is a -deep semi-arid pocket with only a patchy forest (Fig. 54, p. 79).[25] In -places the degree of seclusion from the wind is so great that the scrub, -cacti, and irrigation remind one strongly of the desert on the border of -an oasis, only here the transition is toward forests instead of barren -wastes. The dense forest, or _montaña_, grows in the zone of clouds and -maximum precipitation between 4,000 and 10,000 feet. At the lower limit -it descends a thousand feet farther on shady slopes than it does on -sunny slopes. The continuous forest is so closely restricted to the -cloud belt that in Fig. 99 the two limits may be seen in one photograph. -All these sharply defined limits and contrasts are due to the fact that -the broad valley, discharging through a narrow and remote gorge, is -really to leeward of all the mountains around it. It is like a real -desert basin except in a lesser degree of exclusion from the rains. If -it were narrow and small the rains formed on the surrounding heights -would be carried over into it. Rain on the hills and sunshine in the -valley is actually the day-by-day weather of the dry season. In the wet -season the sky is overcast, the rains are general, though lighter in the -valley pocket, and plants there have then their season of most rapid -growth. The dry season brings plants to maturity and is the time of -harvest. Hence sugar and cacao plantations on a large scale, hence a -varied life in a restricted area, hence a distinct geographic province -unique in South America. - - -INTER-ANDEAN VALLEY CLIMATES - -Not all the deep Andean valleys lie on or near the eastern border. Some, -like the Apurimac and the Marañon, extend well into the interior of the -Cordillera. Besides these deep remote valleys with their distinct -climatic belts are basins, most of them with outlets to the sea--broad -structural depressions occurring in some cases along large and in others -along small drainage lines. The Cuzco basin at 11,000 feet and the -Abancay basin at 6,000 to 8,000 feet are typical. Both have abrupt -borders, narrow outlets, large bordering alluvial fans, and fertile -irrigable soil. Their difference of elevation occurs at a critical -level. Corn will ripen in the Cuzco basin, but cane will not. Barley, -wheat, and potatoes are the staple crops in the one; sugar-cane, -alfalfa, and fruit in the other. Since both are bordered by high -pastures and by mineralized rocks, the deeper Abancay basin is more -varied. If it were not so difficult to get its products to market by -reason of its inaccessibility, the Abancay basin would be the more -important. In both areas there is less rainfall on the basin floor than -on the surrounding hills and mountains, and irrigation is practised, but -the deeper drier basin is the more dependent upon it. Many small high -basins are only within the limits of potato cultivation. They also -receive proportionately more rain. Hence irrigation is unnecessary. -According as the various basins take in one or another of the different -product levels (Fig. 35) their life is meager and unimportant or rich -and interesting. - -The deep-valley type of climate has the basin factors more strongly -developed. Below the Canyon of Choqquequirau, a topographic feature -comparable with the Canyon of Torontoy, the Apurimac descends to 3,000 -feet, broadens to several miles, and has large alluvial fans built into -it. Its floor is really arid, with naked gravel and rock, cacti stands, -and gnarled shrubs as the chief elements of the landscape. Moreover the -lower part of the valley is the steeper. A former erosion level is -indicated in Fig. 125. When it was in existence the slopes were more -moderate than now and the valley broad and open. Thereupon came uplift -and the incision of the stream to its present level. As a result, a -steep canyon was cut in the floor of a mature valley. Hence the slopes -are in a relation unlike that of most of the slopes in our most familiar -landscapes. The gentle slopes are above, the steep below. The break -between the two, a topographic unconformity, may be distinctly traced. - -[Illustration: FIG. 96--Snow-capped mountain, Soiroccocha, north of -Arma, Cordillera Vilcapampa. The blue glacier ice descends almost to the -edge of a belt of extraordinary woodland growing just under the -snowline. The glacier is seen to overhang the valley and to have built -on the steep valley wall terminal moraines whose outer slopes are almost -precipitous.] - -[Illustration: FIG. 97--Shrubby vegetation mixed with grass at 14,000 -feet (4,270 m.) on the northern or sunny slopes of the Cordillera -Vilcapampa above Pampaconas, a thousand feet below the snowline. The -grass is remarkably profuse and supports the flocks and herds of a -pastoral population.] - -[Illustration: FIG. 98--Dense ground cover, typical trees, epiphytes, -and parasites of the tropical rain forest at 2,500-3,000 feet between -Pongo de Mainique and Rosalina.] - -[Illustration: FIG. 99--The Urubamba Valley below Santa Ana. On the dry -valley floor is a mixed growth of scattered trees, shrubs and grass, -with shrubs predominating. Higher up a more luxuriant ravine vegetation -appears. On the upper spurs true forest patches occupy the shady slopes. -Finally, in the zone of clouds at the top of the picture is a continuous -forest. See Fig. 17, for regional applications.] - -Combined with these topographic features are certain climatic features -of equal precision. Between 7,000 and 13,000 feet is a zone of clouds -oftentimes marked out as distinctly as the belt of fog on the Peruvian -coast.[26] Rarely does it extend across the valley. Generally it hangs -as a white belt on the opposite walls. When the up-valley winds of day -begin to blow it drifts up-valley, oftentimes to be dissolved as it -strikes the warmer slopes of the upper valley, just as its settling -under surface is constantly being dissolved in the warm dry air of the -valley floor. Where the precipitation is heaviest there is a belt of -woodland--dark, twisted trees, moss-draped, wet--a Druid forest. Below -and above the woodland are grassy slopes. At Incahuasi a spur runs out -and down until at last it terminates between two deep canyons. No -ordinary wells could be successful. The ground water must be a thousand -feet down, so a canal, a tiny thing only a few inches wide and deep, has -been cut away up to a woodland stream. Thence the water is carried down -by a contour-like course out of the woodland into the pasture, and so -down to the narrow part of the spur where there is pasture but no -springs or streams. - -Corn fields surround the few scattered habitations that have been built -just above the break or shoulder on the valley wall where the woodland -terminates, and there are fine grazing lands. The trails follow the -upper slopes whose gentler contours permit a certain liberty of -movement. Then the way plunges downward over a staircase trail, over -steep boulder-strewn slopes to the arid floor of a tributary where -nature has built a graded route. And so to the still more arid floor of -the main valley, where the ample and moderate slopes of the alluvial -fans with their mountain streams permit plantation agriculture again to -come in. - -To these three climates, the western border type, the eastern border -type, and the inter-Andean type, we have given chief attention because -they have the most important human relations. The statistical records of -the expedition as shown in the curves and the discussion that -accompanies them give attention to those climatic features that are of -theoretical rather than practical interest, and are largely concerned -with the conventional expression of the facts of weather and climate. -They are therefore combined in the following chapter which is devoted -chiefly to a technical discussion of the meteorology as distinguished -from the climatology of the Peruvian Andes. - - - - -CHAPTER X - -METEOROLOGICAL RECORDS FROM THE PERUVIAN ANDES - - -INTRODUCTION - -The data in this chapter, on the weather and climate of the Peruvian -Andes, were gathered under the usual difficulties that accompany the -collection of records at camps scarcely ever pitched at the same -elevation or with the same exposure two days in succession. Some of -them, and I may add, the best, were contributed by volunteer observers -at fixed stations. The observations are not confined to the field of the -Yale Peruvian Expedition of 1911, but include also observations from -Professor Hiram Bingham's Expeditions of 1912 and 1914-15, together with -data from the Yale South American Expedition of 1907. In addition I have -used observations supplied by the Morococha Mining Company through J. P. -Little. Some hitherto unpublished observations from Cochabamba, Bolivia, -gathered by Herr Krüger at considerable expense of money for instruments -and of time from a large business, are also included, and he deserves -the more credit for his generous gift of these data since they were -collected for scientific purposes only and not in connection with -enterprises in which they might be of pecuniary value. My only excuse to -Herr Krüger for this long delay in publication (they were put into my -hands in 1907) is that I have wanted to publish his data in a dignified -form and also to use them for comparison with the data of other climatic -provinces. - -A further word to the reader seems necessary before he examines the -following curves and tables. It would be somewhat audacious to assume -that these short-term records have far-reaching importance. Much of -their value lies in their organization with respect to the data already -published on the climate of Peru. But since this would require a delay -of several years in their publication it seems better to present them -now in their simplest form. After all, the professional climatologist, -to whom they are chiefly of interest, scarcely needs to have such -organization supplied to him. Then, too, we hope that there will become -available in the next ten or fifteen years a vastly larger body of -climatological facts from this region. When these have been collected we -may look forward to a volume or a series of volumes on the "Climate of -Peru," with full statistical tables and a complete discussion of them. -That would seem to be the best time for the reproduction of the detailed -statistics now on hand. It is only necessary that there shall be -sufficient analysis of the data from time to time to give a general idea -of their character and to indicate in what way the scope of the -observations might profitably be extended. I have, therefore, taken from -the available facts only such as seem to me of the most importance -because of their unusual character or their special relations to the -boundaries of plant provinces or of the so-called "natural regions" of -geography. - - -MACHU PICCHU[27] - -The following observations are of special interest in that they -illustrate the weather during the southern winter and spring at the -famous ruins of Machu Picchu in the Canyon of Torontoy. The elevation is -8,500 feet. The period they cover is too short to give more than a hint -of the climate or of the weather for the year. It extends from August -20, 1912, to November 6, 1912 (79 days). - - ANALYTICAL TABLE OF WIND DIRECTIONS, MACHU PICCHU, 1912 - - -----------+--------------------------------------------------------+ - | Number of Observations | - Direction +----------------------------+---------------------------| - of wind | Aug. 20 -- Sept. 30 | Oct. 1 -- Nov. 6 | - | 7 a. m. 1 p. m. 7 p. m. | 7 a. m. 1 p. m. 7 p. m. | - -----------+----------------------------+---------------------------+ - N. | 5 2 5 | 2 -- -- | - N.W. | 9 10 14 | 4 6 11 | - W. | -- 1 2 | 2 2 4 | - S. W. | -- -- 1 | 1 1 6 | - S. | -- -- 1 | -- -- 2 | - S. E. | 4 2 1 | -- -- 3 | - E. | 6 3 3 | 12 4 4 | - N. E. | 8 7 6 | 4 1 3 | - CALM | -- -- 2 | 5 3 3 | - -----------+----------------------------+---------------------------+ - - ----------------------------------------------------------------+ - | Percentages of Total Observation[28] | - Direction|------------------------------------------------------| - of wind | Aug. 20 ---- Sept. 30 | Oct. 1 ---- Nov. 6 | - | 7 a. m. 1 p.m. 7 p. m. | 7 a. m. 1 p. m. 7 p. m.| - ----------------------------------------------------------------| - N. | 15.6 8.0 14.2 | 6.7 ---- ---- | - N. W. | 28.1 40.0 40.0 | 13.3 35.3 30.7 | - W. | ---- 4.0 5.7 | 6.7 11.8 11.1 | - S. W. | ---- ---- 2.8 | 3.3 5.9 16.7 | - S. | ---- ---- 2.8 | ---- ---- 5.5 | - S. E. | 12.5 8.0 2.8 | ---- ---- 8.3 | - E. | 18.8 12.0 8.6 | 40.0 23.5 11.1 | - N. E. | 25.0 28.0 17.1 | 13.3 5.9 8.3 | - CALM | ---- ---- 5.7 | 16.7 17.6 8.3 | - ----------------------------------------------------------------+ - -[Illustration: FIG. 100--Wind roses for Machu Picchu, August 20 to -November 6, 1912.] - -The high percentage of northwest winds during afternoon hours is due to -the up-valley movement of the air common to almost all mountain borders. -The air over a mountain slope is heated more than the free air at the -same elevation over the plains (or lower valley); hence a barometric -gradient towards the mountain becomes established. At Machu Picchu the -Canyon of Torontoy trends northwest, making there a sharp turn from an -equally sharp northeast bend directly upstream. The easterly components -are unrelated to the topography. They represent the trades. If a wind -rose were made for still earlier morning hours these winds would be more -faithfully represented. That an easterly and northeasterly rather than a -southeasterly direction should be assumed by the trades is not difficult -to believe when we consider the trend of the Cordillera--southeast to -northwest. The observations from here down to the plains all show that -there is a distinct change in wind direction in sympathy with the larger -features of the topography, especially the deep valleys and canyons, the -trades coming in from the northeast. - - -CLOUDINESS - -It will be seen that the sky was overcast or a fog lay in the valley 53 -per cent of the time at early morning hours. Even at noon the sky was at -no time clear, and it was more than 50 per cent clear only 18 per cent -of the time. Yet this is the so-called "dry" season of the valleys of -the eastern Andes. The rainfall record is in close sympathy. In the 79 -days' observations rain is recorded on 50 days with a greater proportion -from mid-September to the end of the period (November 6), a distinct -transition toward the wet period that extends from December to May. The -approximate distribution of the rains by hours of observation (7 A. M., -1 P. M., 7 P. M.) was in the ratio 4:3:6. Also the greatest number of -heavy showers as well as the greatest number of showers took place in -the evening. The rainfall was apparently unrelated to wind direction in -the immediate locality, though undoubtedly associated with the regional -movement of the moist plains air toward the mountains. All these facts -regarding clouds and rain plainly show the location of the place in the -belt of maximum precipitation. There is, therefore, a heavy cover of -vegetation. While the situation is admirable for defence, the murky -skies and frequent fogs somewhat offset its topographic surroundings as -a lookout. - - ANALYTICAL TABLE OF THE STATE OF THE SKY, MACHU PICCHU, 1912 - - ---------------+-------------+-------------+ - | Morning | Total | - ---------------+------+------+------+------+ - |Aug.- |Oct.- |Days | % | - |Sept. |Nov. | | | - ---------------+------+------+------+------+ - Foggy | 3.0 | 14.0 | 17.0 | 28.4 | - Overcast | 12.0 | 3.0 | 15.0 | 25.0 | - 50-100% cloudy | 4.0 | 10.0 | 14.0 | 23.3 | - 0-50% cloudy | 6.0 | 4.0 | 10.0 | 16.7 | - Clear | 3.0 | 1.0 | 4.0 | 6.6 | - ---------------+------+------+------+------+ - - ---------------+-------------+-------------+ - | Noon | Total | - ---------------+------+------+------+------+ - |Aug.- |Oct.- | Days | % | - |Sept. |Nov. | | | - ---------------+------+------+------+------+ - Foggy | 1.0 | -- | 1.0 | 2.6 | - Overcast | 6.0 | 8.0 | 14.0 | 36.8 | - 50-100% cloudy | 0.0 | 7.0 | 16.0 | 42.2 | - 0-50% cloudy | 5.0 | 2.0 | 7.0 | 18.4 | - Clear | 0.0 | 0.0 | 0.0 | 0.0 | - ---------------+------+------+------+------+ - - ---------------+-------------+------------- - | Evening | Total - ---------------+------+------+------+------ - |Aug.- |Oct.- |Days | % - |Sept. |Nov. | | - ---------------+------+------+------+------ - Foggy | 1.0 | 2.0 | 3.0 | 4.3 - Overcast | 13.0 | 11.0 | 24.0 | 34.8 - 50-100% cloudy | 8.0 | 15.0 | 23.0 | 33.3 - 0-50% cloudy | 9.0 | 4.0 | 13.0 | 18.8 - Clear | 3.0 | 3.0 | 6.0 | 8.8 - ---------------+------+------+------+------ - - -SANTA LUCIA[29] - -Santa Lucia is a mining center in the province of Puno (16° S.), at the -head of a valley here running northeast towards Lake Titicaca. Its -elevation, 15,500 feet above sea level, confers on it unusual interest -as a meteorological station. A thermograph has been installed which -enables a closer study of the temperature to be made than in the case of -the other stations. It is unfortunate, however, that the observations -upon clouds, wind directions, etc., should not have been taken at -regular hours. The time ranges from 8.30 to 11.30 for morning hours and -from 2.30 to 5.30 for afternoon. The observations cover portions of the -years 1913 and 1914. - - -TEMPERATURE - -Perhaps the most striking features of the weather of Santa Lucia are the -highly regular changes of temperature from night to day or the uniformly -great diurnal range and the small differences of temperature from day to -day or the low diurnal variability. For the whole period of nearly a -year the diurnal variability never exceeds 9.5° F. (5.3° C.) and for -days at a time it does not exceed 2-3° F. (1.1°-1.7° C.). The most -frequent variation, occurring on 71 per cent of the total number of -days, is from 0-3° F., and the mean for the year gives the low -variability of 1.9° F. (1.06° C.). These facts, illustrative of a type -of weather comparable in _uniformity_ with low stations on the Amazon -plains, are shown in the table following as well as in the accompanying -curves. - - FREQUENCY OF THE DIURNAL VARIABILITY, SANTA LUCIA, 1913-14 - - ----------+----+----+----+----+-----+ - | | | | | | - Degrees F.|May |June|July|Aug.|Sept.| - ----------+----+----+----+----+-----+ - 0 | -- | 2 | 6 | 3 | 4 | - 0-1 | 2 | 7 | 7 | 5 | 6 | - 1-2 | 11 | 5 | 7 | 11 | 7 | - 2-3 | 2 | 8 | 8 | 9 | 3 | - 3-4 | 4 | 4 | 2 | 1 | 4 | - 4-5 | 1 | 3 | 1 | -- | 2 | - Over 5 | -- | 1 | -- | 2 | 4 | - ----------+----+----+----+----+-----+ - Days per| 20 | 30 | 31 | 31 | 30 | - month| | | | | | - ----------+----+----+----+----+-----+ - - ----------+----+----+----+----+----+-----++--------- - | | | | | | ||Total No. - Degrees F.|Oct.|Nov.|Dec.|Jan.|Feb.|March||of days - ----------+----+----+----+----+----+-----++--------- - 0 | 6 | 2 | -- | 1 | -- | 2 || 26 - 0-1 | 4 | 8 | 12 | 14 | 9 | 5 || 79 - 1-2 | 8 | 5 | 5 | 4 | 9 | 13 || 85 - 2-3 | 7 | 7 | 5 | 5 | 4 | 6 || 64 - 3-4 | 1 | 3 | 6 | 2 | 4 | 2 || 33 - 4-5 | 1 | 3 | -- | 2 | 1 | 1 || 15 - Over 5 | 4 | 2 | 2 | 3 | 1 | -- || 19 - ----------+----+----+----+----+----+-----++--------- - Days per| 31 | 30 | 30 | 31 | 28 | 29 || 321 - month| | | | | | || - ----------+----+----+----+----+----+-----++--------- - -If we take the means of the diurnal variations by months we have a still -more striking curve showing how little change there is between -successive days. June and December are marked by humps in the curve. -They are the months of extreme weather when for several weeks the -temperatures drop to their lowest or climb to their highest levels. -Moreover, there is at these lofty stations no pronounced lag of the -maximum and minimum temperatures for the year behind the times of -greatest and least heating such as we have at lower levels in the -temperate zone. Thus we have the highest temperature for the year on -December 2, 70.4° F. (21.3° C.), the lowest on June 3, 0.2° F. (--17.7° -C.). The daily maxima and minima have the same characteristic. Radiation -is active in the thin air of high stations and there is a very direct -relation between the times of greatest heat received and greatest heat -contained. The process is seen at its best immediately after the sun is -obscured by clouds. In five minutes I have observed the temperature drop -20° F. (11.1° C.) at 16,000 feet (4,877 m.); and a drop of 10° F. (5.6° -C.) is common anywhere above 14,000 feet (4,267 m.). In the curves of -daily maximum and minimum temperatures we have clearly brought out the -uniformity with which the maxima of high-level stations rise to a mean -level during the winter months (May-August). Only at long intervals is -there a short series of cloudy days when the maximum is 10°-12° F. -(5.6°-6.7° C.) below the normal and the minimum stands at abnormally -high levels. Since clouds form at night in quite variable amounts--in -contrast to the nearly cloudless days--there is a far greater -variability among the minimum temperatures. Indeed the variability of -the winter minima is greater than that of the summer minima, for at the -latter season the nightly cloud cover imposes much more stable -atmospheric temperatures. The summer maxima have a greater degree of -variability. Several clear days in succession allow the temperature to -rise from 5°-10° F. (2.8°-5.6° C.) above the winter maxima. But such -extremes are rather strictly confined to the height of the summer -season--December and January. For the rest of the summer the maxima rise -only a few degrees above those of the winter. This feature of the -climate combines with a December maximum of rainfall to limit the period -of most rapid plant growth to two months. Barley sown in late November -could scarcely mature by the end of January, even if growing on the -Argentine plains and much less at an elevation which carries the night -temperatures below freezing at least once a week and where the mean -temperature hovers about 47° F. (8.3° C.). The proper conditions for -barley growing are not encountered above 13,000 to 13,500 feet and the -farmer cannot be certain that it will ripen above 12,500 feet in the -latitude of Santa Lucia. - -The curve of mean monthly temperatures expresses a fact of great -importance in the plant growth at high situations in the Andes--the -sharp break between the winter and summer seasons. There are no real -spring and autumn seasons. This is especially well shown in the curve -for non-periodic mean monthly range of temperature for the month of -October. During the half of the year that the sun is in the southern -hemisphere the sun's noonday rays strike Santa Lucia at an angle that -varies between 0° and 16° from the vertical. The days and nights are of -almost equal length and though there is rapid radiation at night there -is also rapid insolation by day. When the sun is in the northern -hemisphere the days are shortened from one to two hours and the angle of -insolation decreased, whence the total amount of heat received is so -diminished that the mean monthly temperature lies only a little above -freezing point. In winter the quiet pools beside the springs freeze over -long before dark as the hill shadows grow down into the high-level -valleys, and by morning ice also covers the brooks and marshes. Yet the -sun and wind-cured _ichu_ grass lives here, pale green in summer, -straw-yellow in winter. The tola bush also grows rather abundantly. But -we are almost at the upper limit of the finer grasses and a few hundred -feet higher carries one into the realm of the snowline vegetation, -mosses and lichens and a few sturdy flowering plants. - -For convenience in future comparative studies the absolute extremes are -arranged in the following table: - -[Illustration: FIG. 101 A--DIURNAL TEMPERATURE, SANTA LUCIA, 1913-'14 -C--DIURNAL RANGE OF TEMPERATURE, SANTA LUCIA, 1913-'14 E--DIURNAL -VARIABILITY OF TEMPERATURE, SANTA LUCIA, 1913-'14 B--MEAN MONTHLY -TEMPERATURE, SANTA LUCIA, 1913-'14 D--MONTHLY MEANS OF DIURNAL RANGE OF -TEMPERATURE, SANTA LUCIA, 1913-'14 F--RELATIVE HUMIDITY, SANTA LUCIA, -1913-'14] - - ABSOLUTE MONTHLY EXTREMES, SANTA LUCIA, 1913-14 - - -----------------------+----------++----------+---------------- - Date | Highest || Lowest | Date - -----------------------+----------++----------+---------------- - May[30] (12) | 62° F. || 9° F. | May (25, 26) - June (4 days) | 60° F. || 0.2° F. | June (3) - July (4 days, 31) | 60° F. || 5° F. | July (8) - Aug. (8, 26) | 62° F. || 4° F. | Aug. (4, 5) - Sept. (several days) | 62° F. || 7° F. | Sept. (4 days) - Oct. (24) | 63° F. || 10° F. | Oct. (12, 13) - Nov. (11)[31] | 63° F. || 24.0° F. | Nov. (29) - Dec. (2) | 70.4° F. || 22.2° F. | Dec. (14) - Jan. (19) | 69.5° F. || 26.5° F. | Jan. (3, 15) - Feb. (16, 18) | 63.2° F. || 30.5° F. | Feb. (23) - March (8) | 68.4° F. || 28.5° F. | March (6) - -----------------------+----------++----------+---------------- - - -RAINFALL - -The rainfall record for Santa Lucia is for the year beginning November, -1913. For this period the precipitation amounts to 24.9 inches of which -over 85 per cent fell in the rainy season from November to March. Most -of the rain fell during the violent afternoon tempests that characterize -the summer of these high altitudes. - -The rainfall of Santa Lucia for this first year of record approximates -closely to the yearly mean of 23.8 inches for the station of Caylloma in -the adjacent province of that name. Caylloma is the center of a mining -district essentially similar to Santa Lucia though the elevation of its -meteorological station, 14,196 feet (4,330 m.), is lower. It is one of -the few Peruvian stations for which a comparatively long series of -records is available. The _Boletín de la Sociedad Geográfica de -Lima_[32] contains a résumé of rainfall and temperature for seven years, -1896-7 to 1902-3. Later data may be found in subsequent volumes of the -same publication but they have not been summarized or in any way -prepared for analysis and they contain several typographical errors. A -graphic representation of the monthly rainfall for the earlier period is -here reproduced from the _Boletín de minas del Perú_.[33] The amount -of precipitation fluctuates considerably from year to year. For the -earlier period, with a mean of 23.8 inches the minimum (1896-7) was 8 -inches and the maximum (1898-9) 36 inches. For the later period, 1903-4 -to 1910-11, with a mean of 29.5 inches the minimum (1904-5) was 17.5 -inches and the maximum (1906-7) was 43 inches. - -[Illustration: FIG. 102--Monthly rainfall of Santa Lucia for the year -November, 1913, to October, 1914. No rain fell in July and August.] - -[Illustration: FIG. 103A--Maximum, mean and minimum monthly rainfall of -Caylloma for the period 1896-7 to 1902-3. July was absolutely rainless. -Caylloma is situated immediately east of the crest of the Maritime -Cordillera in a position similar to that of Santa Lucia (see Fig. 66).] - -[Illustration: FIG. 103B--Annual rainfall of Caylloma for the periods -1896-7 to 1902-3; 1903-4 to 1910-11 and for 1915-6 (incomplete: May and -June, months of low rainfall, are missing). Means for the respective -seven and eight year periods are shown and the rainfall of Santa Lucia -for the single observation year is inserted for comparison.] - - RAINFALL, SANTA LUCIA, NOV. 1913 TO OCT. 1914 - - ---------+---------+----------+----------+--------------- - |No of |No. of |Max. for |Total rainfall - |fine days|rainy days|single day|in inches - ---------+---------+----------+----------+--------------- - November | 9 | 21 | 1.150 | 4.264[34] - December | 16 | 15 | .700 | 6.439 - January | 17 | 14 | .610 | 3.313 - February | 9 | 17 | .910 | 2.975 - March | 11 | 20 | 1.102 | 4.381 - April | 17 | 13 | 0.31 | 0.92 - May | 8 | 23 | 0.35 | 1.63 - June | 27 | 3 | 0.05 | 0.07 - July | 31 | 0 | 0.00 | 0.00 - August | 31 | 0 | 0.00 | 0.00 - September| 23 | 7 | 0.05 | 0.35 - October | 21 | 10 | 0.14 | 0.56 - ---------+---------+----------+----------+--------------- - Total | | | | 24.902 - ---------+---------+----------+----------+--------------- - - -WIND - -An analysis of the wind at Santa Lucia shows an excess of north and -south winds over those of all other directions. The wind-rose for the -entire period of observation (Fig. 104) clearly expresses this fact. -When this element is removed we observe a strongly seasonal distribution -of the wind. The winter is the time of north and south winds. In summer -the winds are chiefly from the northeast or the southwest. Among single -months, August and February show this fact clearly as well as the less -decisive character of the summer (February) wind. - -The mean wind velocity for the month of February was 540 meters per -minute for the morning and 470 meters per minute for the afternoon. The -higher morning rate, an unusual feature of the weather of high -stations, or indeed of wind-phenomena in general, is due, however, to -exceptional changes in wind strength on two days of the month, the 16th -and 25th, when the velocity decreased from a little less than a thousand -meters per minute in the morning to 4 and 152 meters respectively in the -afternoon. More typical is the March record for 1914 at Santa Lucia, -when the wind was _always_ stronger in the afternoon than in the -morning, their ratios being 550 to 510. - -[Illustration: Fig. 104--Monthly wind roses for Santa Lucia, June, 1913, -to July, 1914, and composite rose for the whole period of observation.] - - -CLOUD - -The greater strength of the afternoon wind would lead us to suppose that -the cloudiness, which in the trade-wind belt, is to so great an extent -dependent on the wind, is greatest in the afternoon. The diagrams bring -out this fact. Barely is the sky quite clear after the noon hour. Still -more striking is the contrast between the morning and afternoon if we -combine the two densest shadings of the figures. Light, high-lying -cirrus clouds are most characteristic of early morning hours. They -produce some very striking sky effects just before sunrise as they catch -the sun's rays aloft. An hour or two after sunrise they disappear and -small cumulus clouds begin to form. These grow rapidly as the winds -begin and by afternoon become bulky and numerous. In the wet season they -grow into the nimbus and stratus types that precede a sudden downpour of -water or a furious hailstorm. This is best seen from the base of a -mountain range looking towards the crest, where the cloud-and -rain-making processes of this type are most active. - - CLOUD ANALYSIS, SANTA LUCIA - - --------------+---------+---------+---------+---------+---------++---------+ - | Nov. | Dec. | Jan. | Feb. | March || Total | - Type of cloud |a.m. p.m.|a.m. p.m.|a.m. p.m.|a.m. p.m.|a.m. p.m.||a.m. p.m.| - --------------+---------+---------+---------+---------+---------++---------+ - Cirrus | 6 2 | 15 2 | 9 2 | 5 3 | 6 3 || 41 12 | - Cirro-stratus | -- -- | -- -- | -- -- | -- -- | -- -- || -- -- | - Cirro-cumulus | 4 4 | 7 11 | 3 5 | 6 8 | 17 10 || 37 38 | - Cumulus | 3 4 | 4 7 | 10 9 | 15 13 | 5 13 || 37 46 | - Strato-cumulus| 2 6 | 3 10 | 7 14 | 2 3 | -- 3 || 14 36 | - Stratus | -- -- | -- 1 | -- -- | -- 1 | 1 2 || 2 4 | - Nimbus | -- -- | -- -- | -- -- | -- -- | -- -- || -- -- | - Clear | -- -- | 2 -- | 2 1 | -- -- | 2 -- || 6 1 | - --------------+---------+---------+---------+---------+---------++---------+ - - -UNUSUAL WEATHER PHENOMENA, SANTA LUCIA, 1913-14 - -[Illustration: Fig. 105--Monthly cloudiness of Santa Lucia from January -to July, 1914. Mean cloudiness for the whole period is also shown.] - -The following abstracts are selected because they give some important -features of the weather not included in the preceding tables and graphs. -Of special interest are the strong contrasts between the comparatively -high temperatures of midday and the sudden "tempests" accompanied by -rain or hail that follow the strong convectional movements dependent -upon rapid and unequal heating. The furious winds drive the particles of -hail like shot. It is sometimes impossible to face them and the pack -train must be halted until the storm has passed. Frequently they leave -the ground white with hailstones. We encountered one after another of -these "tempestades" on the divide between Lambrama and Antabamba in -1911. They are among the most impetuous little storms I have ever -experienced. The longest of them raged on the divide from two-o'clock -until dark, though in the valleys the sun was shining. Fortunately, in -this latitude they do not turn into heavy snowstorms as in the -Cordillera of northwestern Argentina, where the passes are now and then -blocked for weeks at a time and loss of human life is no infrequent -occurrence.[35] They do, however, drive the shepherds down from the -highest slopes to the mid-valley pastures and make travel uncomfortable -if not unsafe. - -ABSTRACT FROM DAILY WEATHER OBSERVATIONS, SANTA LUCIA, 1913-14 - - NOVEMBER - - "Tempest" recorded 11 times, distant thunder and lightning 9 times. - Unusual weather records: "clear sky, scorching sun, good weather" - (Nov. 29); "morning sky without a single cloud, weather agreeable" - (Nov. 30). - - DECEMBER - - Clear morning sky 6 times. Starry night or part of night 7 times. - Beginning of rain and strong wind frequently observed at 5-6 P.M. - "Tempest" mentioned 19 times--5 times at midnight, 8 times at 5-6 - P.M. - - JANUARY - - Clear morning sky 5 times. Starry night 3 times. Rain, actual or - threatening, characteristic of afternoons. "Tempest," generally - about 5-6 P.M., 7 times. Sun described 4 times as scorching and, - when without wind, heat as stifling. Weather once "agreeable." - - FEBRUARY - - Constant cloud changes, frequent afternoon or evening rains. - "Tempest," generally 4 P.M. and later, 16 times. - - MARCH - - Twice clear morning skies, once starry night. Scorching sun and - stifling heat on one occasion. "Tempest," generally in late - afternoon and accompanied by hail, 19 times. Observed 3 or 4 times - a strong, "land breeze" (terral) of short duration (15-20 mins.) - and at midnight. - - -MOROCOCHA - -Morococha, in the Department of Ancachs, Peru, lies in 76° 11' west -longitude and 11° 45' south latitude and immediately east of the crest -line of the Maritime Cordillera. It is 14,300 feet above sea level, and -is surrounded by mountains that extend from 1,000 to 3,000 feet higher. -The weather records are of special interest in comparison with those of -Santa Lucia. Topographically the situations of the two stations are -closely similar hence we may look for climatic differences dependent on -the latitudinal difference. This is shown in the heavier rainfall of -Morococha, 4° nearer the equatorial climatic zone. (For location see -Fig. 66.) - -The meteorological data for 1908-09 were obtained from records kept by -the Morococha Mining Company for use in a projected hydro-electric -installation. Other data covering the years 1906-11 have appeared in the -bulletins of the _Sociedad Geográfica de Lima_. These are not complete -but they have supplied rainfall data for the years 1910-11;[36] those -for 1906 and 1907 have been obtained from the _Boletín de Minas_.[37] - - -TEMPERATURE - -The most striking facts expressed by the various temperature curves are -the shortness of the true winter season--its restriction to June and -July--and its abrupt beginning and end. This is well known to anyone who -has lived from April to October or November at high elevations in the -Central Andes. Winter comes on suddenly and with surprising regularity -from year to year during the last few days of May and early June. In the -last week of July or the first week of August the temperatures make an -equally sudden rise. During 1908 and 1909 the mean temperature reached -the freezing point but once each year--July 24 and July 12 -respectively. The absolute minimum for the two years was -22° C. July of -1908 and June of 1909 are also the months of smallest diurnal -variability, showing that the winter temperatures are maintained with -great regularity. Like all tropical high-level stations, Morococha -exhibits winter maxima that are very high as compared with the winter -maxima of the temperate zone. In both June and July of 1908 and 1909 the -maximum was maintained for about a week above 55° F. (12.8° C.), and in -1909 above 60° F. (15.6° C.), the mean maximum for the year being only -4.7° F. higher. For equal periods, however, the maxima fell to levels -about 10° F. below those for the period from December to May, 1908. - -It is noteworthy that the lowest maximum for 1909 was in October, 44° F. -(6.7° C.); and that other low maxima but little above those of June and -July occur in almost all the other months of the year. While 1909 was in -this respect an exceptional year, it nevertheless illustrates a fact -that may occur in any month of any year. Its occurrence is generally -associated with cloudiness. One of the best examples of this is found in -the January maximum curve for 1909, where in a few days the maxima fell -12° F. Cloud records are absent, hence a direct comparison cannot be -made, but a comparison of the maximum temperature curve with the graphic -representation of mean monthly rainfall, will emphasize this relation of -temperature and cloudiness. February was the wettest month of both 1908 -and 1909. In sympathy with this is the large and sharp drop from the -January level of the maxima--the highest for the year--to the February -level. The mean temperatures are affected to a less degree because the -cloudiness retards night radiation of heat, thus elevating the maxima. -Thus in 1908 the lowest minimum for both January and February was 28.4° -F. (-2° C.). For 1909 the minima for January and February were 27.5° F. -(-2.5° C.) and 29.3° F. (-1.5° C.) respectively. - -[Illustration: FIG. 106 A--DIURNAL TEMPERATURE, MOROCOCHA, 1908 - -B--DIURNAL TEMPERATURE, MOROCOCHA, 1909 - -D--DIURNAL RANGE OF TEMPERATURE, MOROCOCHA, 1908 - -E--DIURNAL RANGE OF TEMPERATURE, MOROCOCHA, 1909 - -G--DIURNAL VARIABILITY OF TEMPERATURE, MOROCOCHA, 1908 - -H--DIURNAL VARIABILITY OF TEMPERATURE, MOROCOCHA, 1909 - -C--MEAN MONTHLY TEMPERATURE, MOROCOCHA - -F--MONTHLY MEANS OF DIURNAL RANGE OF TEMPERATURE, MOROCOCHA] - -The extent to which high minima may hold up the mean temperature is -shown by the fact that the mean monthly temperature for January, 1908, -was lower than for February. Single instances illustrate this relation -equally well. For example, on March 5th, 1908, there occurred the -heaviest rainfall of that year. The maximum and minimum curves almost -touch. The middle of April and late September, 1909, are other -illustrations. The relationship is so striking that I have put the two -curves side by side and have had them drawn to the same scale. - - FREQUENCY OF THE DIURNAL VARIABILITY, MOROCOCHA, 1908 AND 1909 - - 1908 - ----------------------------------------------------------------- - Degrees | | | | | | | | | | | | |Total No. - F. | J.| F.| M.| A.| M.| J.| J.| A.| S.| O.| N.| D.| of days - --------+---+---+---+---+---+---+---+---+---+---+---+---+--------- - 0 | --| 3 | 2 | 3 | --| --| 2 | 1 | 3 | 1 | 1 | 3 | 19 - 0-1 | 6 | 5 | 6 |10 | 9 |10 |13 |10 | 8 | 6 | 6 | 5 | 94 - 1-2 | 4 | 1 | 3 | 7 | 5 | 3 | 7 | 7 | 8 | 6 | 6 | 4 | 61 - 2-3 | 6 | 1 | 3 | 4 | 9 | 2 | 2 | 4 | 4 | 7 | 7 | 4 | 53 - 3-4 | 5 | 3 | 2 | 3 | 3 | 4 | 2 | 9 | 4 | 5 | 3 | 5 | 48 - 4-5 | 2 | 3 | 1 | 1 | 2 | 5 | 5 | --| 1 | 1 | 6 | 3 | 30 - Over 5 | 3 | 4 | 3 | 2 | 3 | 6 | --| --| 2 | 5 | 1 | 5 | 34 - --------+---+---+---+---+---+---+---+---+---+---+---+---+--------- - Days per|26 |20 |20 |30 |31 |30 |31 |31 |30 |31 |30 |20 | 339 - month | | | | | | | | | | | | | - ------------------------------------------------------------------ - 1909 - --------------------------------------------------------------------- - | | | | | | | | | | | | | |Mean - Degrees | | | | | | | | | | | | |Total |for - F. | J.| F.| M.| A.| M.| J.| J.| A.| S.| O.| N.| D.|No. of|1908 - | | | | | | | | | | | | | days |-1909 - --------+---+---+---+---+---+---+---+---+---+---+---+---+------+----- - 0 | 6 | 1 | 4 | 2 | 1 | 2 | 4 | 4 | 3 | 6 | 2 | 1 | 36 | 27.5 - 0-1 | 9 | 8 | 5 | 6 | 6 | 7 | 8 |13 | 9 | 4 |11 |10 | 96 | 95 - 1-2 | 4 | 6 | 8 | 3 |11 |14 | 3 | 3 | 5 | 3 | 9 | 6 | 75 | 68 - 2-3 | 3 | 7 | 4 | 8 | 4 | 3 | 6 | 6 | 4 | 6 | 1 | 3 | 55 | 54 - 3-4 | 4 | 5 | 3 | 6 | 4 | 4 | 4 | 3 | 6 | 3 | 2 | 5 | 49 | 48.5 - 4-5 | 1 | 1 | 5 | 1 | 2 | --| 2 | 1 | 1 | 2 | --| 2 | 18 | 24 - Over 5 | 4 | --| 2 | 4 | 3 | --| 4 | 1 | 2 | 7 | 5 | 3 | 35 | 34.5 - --------+---+---+---+---+---+---+---+---+---+---+---+---+------+----- - Days per|31 |28 |31 |30 |31 |30 |31 |31 |30 |31 |30 |30 | 364 |351.5 - month | | | | | | | | | | | | | | - --------------------------------------------------------------------- - - -RAINFALL - -The annual rainfall of Morococha is as follows: - - 1906 28 inches ( 712 mm.) - 1907 40 " (1,011 mm.)[38] - 1908 57 " (1,450 mm.) - 1909 45 " (1,156 mm.) - 1910 47 " (1,195 mm.) - 1911 25 " ( 622 mm.) - -[Illustration: FIG. 107A.] - -[Illustration: FIG. 107B.] - -[Illustration: FIG. 107C.] - -[Illustration: Fig. 107--Rainfall of Morococha. Fig. 107A shows daily -rainfall during the rainy (summer) season, 1908-1909. Fig. 107B shows -monthly rainfall from July, 1905, to December, 1911, and Fig. 107C the -annual and mean rainfall for the same period.] - -The mean for the above six years amounts to 40 inches (1,024 mm.). This -is a value considerably higher than that for Caylloma or Santa Lucia. -The greater rainfall of Morococha is probably due in part to its more -northerly situation. An abnormal feature of the rainfall of 1908, the -rainiest year, is the large amount that fell in June. Ordinarily June -and July, the coldest months, are nearly or quite rainless. The normal -concurrence of highest temperatures and greatest precipitation is of -course highly favorable to the plant life of these great altitudes. Full -advantage can be taken of the low summer temperatures if the growing -temperatures are concentrated and are accompanied by abundant rains. -Since low temperatures mean physiologic dryness, whether or not rains -are abundant, the dryness of the winter months has little effect in -restricting the range of Alpine species. - -The seasonal distribution of rain helps the plateau people as well as -the plateau plants. The transportation methods are primitive and the -trails mere tracks that follow the natural lines of topography and -drainage. Coca is widely distributed, likewise corn and barley which -grow at higher elevations, and wool must be carried down to the markets -from high-level pastures. In the season of rains the trails are -excessively wet and slippery, the streams are often in flood and the -rains frequent and prolonged. On the other hand the insignificant -showers of the dry or non-growing season permit the various products to -be exchanged over dry trails. - -The activities of the plateau people have had a seasonal expression from -early times. Inca chronology counted the beginning of the year from the -middle of May, that is when the dry season was well started and it was -inaugurated with the festivals of the Sun. With the exception of June -when the people were entirely busied in the irrigation of their fields, -each month had its appropriate feasts until January, during which month -and February and March no feasts were held. April, the harvest month, -marked the recommencement of ceremonial observances and a revival of -social life.[39] - -In Spanish times the ritualistic festivals, incorporated with fairs, -followed the seasonal movement. Today progress in transportation has -caused the decadence of many of the fairs but others still survive. Thus -two of the most famous fairs of the last century, those of Vilque -(province of Puno) and Yunguyo (province of Chucuito), were held at the -end of May and the middle of August respectively. Copacavana, the famous -shrine on the shores of Titicaca, still has a well-attended August fair -and Huari, in the heart of the Bolivian plateau, has an Easter fair -celebrated throughout the Andes. - - -COCHABAMBA - -Cochabamba, Bolivia, lies 8,000 feet above sea level in a broad basin in -the Eastern Andes. The Cerro de Tunari, on the northwest, has a snow and -ice cover for part of the year. The tropical forests lie only a single -long day's journey to the northeast. Yet the basin is dry on account of -an eastern front range that keeps out the rain-bearing trade winds. The -Rio Grande has here cut a deep valley by a roundabout course from the -mountains to the plains so that access to the region is over bordering -elevations. The basin is chiefly of structural origin. - -The weather records from Cochabamba are very important. I could obtain -none but temperature data and they are complete for 1906 only. Data for -1882-85 were secured by von Boeck[40] and they have been quoted by -Sievers and Hann. The mean annual temperature for 1906 was 61.9° F. -(16.6° C.), a figure in close agreement with von Boeck's mean of 60.8° -F. (16° C.). The monthly means indicate a level of temperature favorable -to agriculture. The basin is in fact the most fertile and highly -cultivated area of its kind in Bolivia. Bananas, as well as many other -tropical and subtropical plants, grow in the central plaza. The nights -of midwinter are uncomfortably cool; and the days of midsummer are -uncomfortably hot but otherwise the temperatures are delightful. The -absolute extremes for 1906 were 81.5° F. (27.5° C.) on December 11, and -39.9° F. (4.4° C.) on July 15 and 16. The (uncorrected) readings of von -Boeck give a greater range. High minima rather than high maxima -characterize the summer. The curve for 1906 shows the maxima for June -and July cut off strikingly by an abrupt drop of the temperature and -indicates a rather close restriction of the depth of the season to these -two months, which are also those of greatest diurnal range. - -[Illustration: FIG. 108 A--DIURNAL TEMPERATURE, COCHABAMBA, 1906 - -B--DIURNAL TEMPERATURE, COCHABARMBA, 1907 - -E--DIURNAL RANGE OF TEMPERATURE, COCHABARMBA, 1907 - -D--DIURNAL RANGE OF TEMPERATURE, COCHABARMBA, 1906 - -G--DIURNAL VARIABILITY, COCHABARMBA, 1906 - -H--DIURNAL VARIABILITY, COCHABAMBA, 1907 - -C--MEAN MONTHLY TEMPERATURES, COCHABAMBA - -F--MONTHLY MEANS OF DIURNAL RANGE, COCHABAMBA] - -The rainfall of about 18 inches is concentrated in the summer season, 85 -per cent falling between November and March. During this time the town -is somewhat isolated by swollen streams and washed out trails: hence -here, as on the plateau, there is a distinct seasonal distribution of -the work of planting, harvesting, moving goods, and even mining, and of -the general commerce of the towns. There is an approach to our winter -season in this respect and in respect of a respite from the almost -continuously high temperatures of summer. The daytime temperatures of -summer are however mitigated by the drainage of cool air from the -surrounding highlands. This, indeed, prolongs the period required for -the maturing of plants, but there are no harmful results because -freezing temperatures are not reached, even in winter. - - MONTHLY TEMPERATURES, COCHABAMBA, 1906 - - -------------+-------------+-------------+-------------+-------------- - Month | Mean Min. | Mean Max. | Mean Range | Daily Mean - -------------+-------------+-------------+-------------+-------------- - January | 55.7 | 72.25 | 16.65 | 63.3 - February | 61.2 | 71.3 | 10.1 | 65.5 - March | 59.8 | 72.6 | 12.8 | 65.5 - April | 55.06 | 70.8 | 15.74 | 62.2 - May | 50.9 | 68.7 | 17.8 | 59.1 - June | 47.1 | 65.6 | 18.5 | 55.6 - July | 44.8 | 64.9 | 20.1 | 54.1 - August | 49.9 | 68.0 | 18.1 | 58.2 - September | 55.6 | 73.2 | 17.6 | 63.7 - October | 56.1 | 73.4 | 17.3 | 64.0 - November | 58.1 | 75.7 | 17.6 | 66.2 - December | 58.6 | 73.9 | 15.3 | 65.8 - -------------+-------------+-------------+-------------+-------------- - -[Illustration: FIGS. 109-113--Temperature curves for locations in the -montaña, July and August, 1911. The curves are based on hourly readings -with interpolated readings for such critical occurrences as the -appearance of cloud or rain. Dry bulb readings are shown by solid lines, -wet bulb by dotted lines, and breaks in the continuity of the -observations by heavy broken lines. Fig. 109 is for Pongo de Mainique, -August 20 and 21; Fig. 110 for Yavero; Fig. 111 for Santo Anato, August -11 and 12; Fig. 112 for Sahuayaco, August 20, and Fig. 113 for Santa -Ana, July 30 to August 1.] - -[Illustration: FIG. 114--Typical afternoon cloud composition at Santa -Ana during the dry season.] - -[Illustration: FIG. 115--Temperature curve for Abancay drawn from data -obtained by hourly readings on September 27, 1911. Dry bulb readings are -shown by a heavy solid line, wet bulb readings by a dotted line. The -heavy broken line shows the normal curve when the sky is unobscured by -cloud. The reduction in temperature with cloud is very marked.] - - FREQUENCY OF DIURNAL VARIABILITY AT COCHABAMBA, 1906 - - -------+----+----+----+----+----+----+----+----+----+----+----+----++------ - | | | | | | | | | | | | ||Total - Degrees| | | | | | | | | | | | ||No. of - F. | J. | F. | M. | A. | M. | J. | J. | A. | S. | O. | N. | D. || days - -------+----+----+----+----+----+----+----+----+----+----+----+----++------ - 0 | 1 | 3 | 10 | 12 | 6 | 10 | 9 | 6 | 9 | 6 | 3 | 4 || 79 - 0-1 | 5 | -- | 3 | 5 | 3 | 3 | -- | 4 | -- | 3 | 1 | 1 || 28 - 1-2 | 10 | 10 | 13 | 11 | 15 | 7 | 14 | 11 | 15 | 10 | 14 | 13 || 143 - 2-3 | 7 | 11 | 3 | 1 | 5 | 8 | 7 | 4 | 3 | 6 | 7 | 6 || 68 - 3-4 | 6 | 2 | 2 | 1 | 2 | 2 | 1 | 6 | 3 | 4 | 3 | 5 || 37 - 4-5 | -- | -- | -- | -- | -- | -- | -- | -- | -- | 1 | 1 | 1 || 3 - Over 5 | 2 | 2 | -- | -- | -- | -- | -- | -- | -- | 1 | 1 | 1 || 7 - -------+----+----+----+----+----+----+----+----+----+----+----+----++------ - -A series of curves shows the daily march of temperature at various -locations along the seventy-third meridian. Figs. 109 to 113 are for the -Urubamba Valley. Respectively they relate to Pongo de Mainique, 1,200 -feet elevation (365 m.), the gateway to the eastern plains; Yavero, -1,600 feet (488 m.), where the tributary of this name enters the main -stream; Santo Anato, 1,900 feet (580 m.); Sahuayaco, 2,400 feet (731 -m.), and Santa Ana, 3,400 feet (1,036 m.), one of the outposts of -civilization beyond the Eastern Cordillera. The meteorological -conditions shown are all on the same order. They are typical of dry -season weather on the dry floor of a montaña valley. The smooth curves -of clear days are marked by high mid-day temperatures and great diurnal -range. Santo Anato is a particularly good illustration: the range for -the 24 hours is 38° F. (21.1° C.). This site, too, is remarkable as one -of the most unhealthful of the entire valley. The walls of the valley -here make a sharp turn and free ventilation of the valley is obstructed. -During the wet season tertian fever prevails to a degree little known -east of the Cordillera, though notorious enough in the deep valleys of -the plateau. The curves show relative humidity falling to a very low -minimum on clear days. At Santo Anato and Santa Ana, for example, it -drops below 30 per cent during the heat of the day. Afternoon -cloudiness, however, is a common feature even of the dry season. A -typical afternoon cloud formation is shown in Fig. 114. The effect on -temperature is most marked. It is well shown in the curve for August 20 -and 22 at Yavero. Cloudiness and precipitation increase during the -summer months. At Santa Ana the rainfall for the year 1894-95 amounted -to 50 inches, of which 60 per cent fell between December and March. For -a discussion of topographic features that have some highly interesting -climatic effects in the eastern valleys of Peru see Chapter VI. - -[Illustration: FIGS. 116-118--Temperature curves for locations in the -Maritime Cordillera and its western valleys, October, 1911. For -construction of curves see Figs. 109-113. Fig. 116 is for Camp 13 on the -northern slope of the Maritime Cordillera (which here runs from east to -west), October 13-15; Fig. 117 for Cotahuasi, October 26; Fig. 118 for -Salamanca, October 31.] - -[Illustration: FIG. 119. - -FIG. 120. - -FIGS. 119-120--Temperature curves for the Coast Desert, November, 1911. -Fig. 119 is for Aplao, November 4 and 5; and Fig. 120 for Camaná, -November 9 and 10. For construction of curves see Figs. 109 to 113.] - -Abancay, 8,000 feet (2,440 m.), in one of the inter-Andean basins, is -situated in the zone of marked seasonal precipitation. The single day's -record shows the characteristic effect of cloud reducing the maximum -temperature of the day and maintaining the relative humidity. - -Camp 13, 15,400 feet (4,720 m.), lies near the crest of the Maritime -Cordillera a little south of Antabamba. Afternoon storms are one of its -most significant features. Cotahuasi, 9,100 feet (2,775 m.) is near the -head of a west-coast valley. Its low humidity is worthy of note. That -for Salamanca, 12,700 feet (3,870 m.), is similar but not so marked. - -Aplao, 3,100 feet (945 m.), and Camaná at the seacoast are stations in -the west-coast desert. The interior location of the former gives it a -greater range of temperature than Camaná, yet even here the range is -small in comparison with the diurnal extremes of the montaña, and the -tempering effect of the sea-breeze is clearly apparent. Camaná shows a -diurnal temperature range of under 10° F. and also the high relative -humidity, over 70 per cent, characteristic of the coast. - - - - -PART II - -PHYSIOGRAPHY OF THE PERUVIAN ANDES - - - - -CHAPTER XI - -THE PERUVIAN LANDSCAPE - - -From the west coast the great Andean Cordillera appears to have little -of the regularity suggested by our relief maps. Steep and high cliffs in -many places form the border of the land and obstruct the view; beyond -them appear distant summits rising into the zone of clouds. Where the -cliffs are absent or low, one may look across a sun-baked, yellow -landscape, generally broken by irregular foothills that in turn merge -into the massive outer spurs and ranges of the mountain zone. The plain -is interrupted by widely separated valleys whose green lowland meadows -form a brilliant contrast to the monotonous browns and yellows of the -shimmering desert. In rare situations the valley trenches enable one to -look far into the Cordillera and to catch memorable glimpses of lofty -peaks capped with snow. - -If the traveler come to the west-coast landscape from the well-molded -English hills or the subdued mountains of Vermont and New Hampshire with -their artistic blending of moderate profiles, he will at first see -nothing but disorder. The scenery will be impressive and, in places, -extraordinary, but it is apparently composed of elements of the greatest -diversity. All the conceivable variations of form and color are -expressed, with a predominance of bold rugged aspects that give a -majestic appearance to the mountain-bordered shore. One looks in vain -for some sign of a quiet view, for some uniformity of features, for some -landscape that will remind him of the familiar hills of home. The Andes -are aggressive mountains that front the sea in formidable spurs or -desert ranges. Could we see in one view their entire elevation from -depths of over 20,000 feet beneath sea level to snowy summits, a total -altitude of 40,000 feet (12,200 m.), their excessive boldness would be -more apparent. No other mountains in the world are at once so -continuously lofty and so near a coast which drops off to abyssal -depths. - -The view from the shore is, however, but one of many which the Andes -exhibit. Seen from the base the towering ranges display a stern aspect, -but, like all mountains, their highest slopes and spurs must be crossed -and re-crossed before the student is aware of other aspects of a quite -different nature. The Andes must be observed from at least three -situations: from the floors of the deep intermontane valleys, from the -intermediate slopes and summits, and from the uppermost levels as along -the range crests and the highest passes. Strangely enough it is in the -summit views that one sees the softest forms. At elevations of 14,000 to -16,000 feet (4,270 to 4,880 m.), where one would expect rugged spurs, -serrate chains, and sharp needles and horns, one comes frequently upon -slopes as well graded as those of a city park--grass-covered, -waste-cloaked, and with gentle declivity (Figs. 121-124). - -The graded, waste-cloaked slopes of the higher levels are interpreted as -the result of prolonged denudation in an erosion cycle which persisted -through the greater part of the Tertiary period, and which was closed by -uplifts aggregating at least several thousands of feet. Above the level -of the mature slopes rise the ragged profiles and steep, naked -declivities of the snow-capped mountains which bear residual relations -to the softer forms at their bases. They are formed upon rock masses of -greater original elevation and of higher resistance to denudation. -Though they are dominating topographic features, they are much less -extensive and significant than the tame landscape which they surmount. - -[Illustration: FIG. 121--Looking north from the hill near Anta in the -Anta basin north of Cuzco. Typical composition of slopes and intermont -basins in the Central Andes. Alluvial fill in the foreground; mature -slopes in the background; in the extreme background the snow-capped -crests of the Cordillera Vilcapampa.] - -[Illustration: FIG. 122--Showing topographic conditions before the -formation of the deep canyons in the Maritime Cordillera. The view, -looking across a tributary canyon of the Antabamba river, shows in the -background the main canyon above Huadquirca. Compare with Fig. 60.] - -Below the level of the mature slopes are topographic features of equal -prominence: gorges and canyons up to 7,000 feet deep. The deeply -intrenched streams are broken by waterfalls and almost continuous -rapids, the valley walls are so abrupt that one may, in places, roll -stones down a 4,000 foot incline to the river bed, and the tortuous -trail now follows a stream in the depths of a profound abyss, now scales -the walls of a labyrinthine canyon. - -[Illustration: FIG. 123--Mature slopes between Ollantaytambo and -Urubamba.] - -[Illustration: FIG. 124--Dissected mature slopes north of Anta in the -Anta basin north of Cuzco.] - -[Illustration: FIG. 125--Mature upper and young lower slopes at the -outlet of the Cuzco basin.] - -The most striking elements of scenery are not commonly the most -important in physiography. The oldest and most significant surface may -be at the top of the country, where it is not seen by the traveler or -where it cannot impress him, except in contrast to features of greater -height or color. The layman frequently seizes on a piece of bad-land -erosion or an outcrop of bright-colored sandstone or a cliff of -variegated clays or a snow-covered mountain as of most interest. All we -can see of a beautiful snow-clad peak is mere entertainment compared -with what subdued waste-cloaked hill-slopes may show. We do not wish to -imply that everywhere the tops of the Andes are meadows, that there are -no great scenic features in the Peruvian mountains, or that they are not -worth while. But we do wish to say that the bold features are far less -important in the interpretation of the landscape. - -Amid all the variable forms of the Peruvian Cordillera certain strongly -developed types recur persistently. That their importance and relation -may be appreciated we shall at once name them categorically and -represent them in the form of a block diagram (Fig. 126). The principal -topographic types are as follows: - - 1. An extensive system of high-level, well-graded, mature slopes, - below which are: - - 2. Deep canyons with steep, and in places, cliffed sides and narrow - floors, and above which are: - - 3. Lofty residual mountains composed of resistant, highly deformed - rock, now sculptured into a maze of serrate ridges and sharp - commanding peaks. - - 4. Among the forms of high importance, yet causally unrelated to - the other closely associated types, are the volcanic cones and - plateaus of the western Cordillera. - - 5. At the valley heads are a full complement of glacial features, - such as cirques, hanging valleys, reversed slopes, terminal - moraines, and valley trains. - - 6. Finally there is in all the valley bottoms a deep alluvial fill - formed during the glacial period and now in process of dissection. - -Though there are in many places special features either remotely related -or quite unrelated to the principal enumerated types, they belong to the -class of minor forms to which relatively small attention will be paid, -since they are in general of small extent and of purely local interest. - -[Illustration: FIG. 126--Block diagram of the typical physiographic -features of the Peruvian Andes.] - -The block diagram represents all of these features, though of necessity -somewhat more closely associated than they occur in nature. Reference to -the photographs, Figs. 121-124, will make it clear that the diagram is -somewhat ideal: on the other hand the photographs together include all -the features which the diagram displays. In descending from any of the -higher passes to the valley floor one passes in succession down a steep, -well-like cirque at a glaciated valley head, across a rocky terminal -moraine, then down a stair-like trail cut into the steep scarps which -everywhere mark the descent to the main valley floors, over one after -another of the confluent alluvial fans that together constitute a large -part of the valley fill, and finally down the steep sides of the inner -valley to the boulder-strewn bed of the ungraded river. - -We shall now turn to each group of features for description and -explanation, selecting for first consideration the forms of widest -development and greatest significance--the high-level mature slopes -lying between the lofty mountains which rise above them and the deep, -steep-walled valleys sunk far below them. These are the great pasture -lands of the Cordillera; their higher portions constitute the typical -_puna_ of the Indian shepherds. In many sections it is possible to -pasture the vagrant flocks almost anywhere upon the graded slopes, -confident that the _ichu_, a tufted forage grass, will not fail and that -scattered brooks and springs will supply the necessary water. At -nightfall the flocks are driven down between the sheltering walls of a -canyon or in the lee of a cliff near the base of a mountain, or, failing -to reach either of these camps, the shepherd confines his charge within -the stone walls of an isolated corral. - -In those places where the graded soil-covered slopes lie within the zone -of agriculture--below 14,000 feet--they are cultivated, and if the soil -be deep and fertile they are very intensively cultivated. Between Anta -and Urubamba, a day's march north of Cuzco, the hill slopes are covered -with wheat and barley fields which extend right up to the summits (Fig. -134). In contrast are the uncultivated soil-less slopes of the mountains -and the bare valley walls of the deeply intrenched streams. The -distribution of the fields thus brings out strongly the principal -topographic relations. Where the softer slopes are at too high a level, -the climatic conditions are extreme and man is confined to the valley -floors and lower slopes where a laborious system of terracing is the -first requirement of agriculture. - -The appearance of the country after the mature slopes had been formed is -brought out in Fig. 122. The camera is placed on the floor of a still -undissected, mature valley which shows in the foreground of the -photograph. In the middle distance is a valley whose great depth and -steepness are purposely hidden; beyond the valley are the smoothly -graded, catenary curves, and interlocking spurs of the mature upland. In -imagination one sees the valleys filled and the valley slopes confluent -on the former (now imaginary) valley floor which extends without -important change of expression to the border of the Cordillera. No -extensive cliffs occur on the restored surface, and none now occur on -large tracts of the still undissected upland. Since the mature slopes -represent a long period of weathering and erosion, their surfaces were -covered with a deep layer of soil. Where glaciation at the higher levels -and vigorous erosion along the canyons have taken place, the former soil -cover has been removed; elsewhere it is an important feature. Its -presence lends a marked softness and beauty to these lofty though -subdued landscapes. - -The graded mountain slopes were not all developed (1) at the same -elevation, nor (2) upon rock of the same resistance to denudation, nor -(3) at the same distance from the major streams, nor (4) upon rock of -the same structure. It follows that they will not all display precisely -the same form. Upon the softer rocks at the lowest levels near the -largest streams the surface was worn down to extremely moderate slopes -with a local relief of not more than several hundred feet. Conversely, -there are quite unreduced portions whose irregularities have mountainous -proportions, and between these extremes are almost all possible -variations. Though the term _mature_ in a broad way expresses the stage -of development which the land had reached, _post mature_ should be -applied to those portions which suffered the maximum reduction and now -exhibit the softest profiles. At no place along the 73rd meridian was -denudation carried to the point of even local peneplanation. All of the -major and some of the minor divides bear residual elevations and even -approximately plane surfaces do not exist. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM, DIRECTOR - -COROPUNA QUADRANGLE - -(_Cotahuasi_)] - -Among the most important features of the mature slopes are (1) their -great areal extent--they are exhibited throughout the whole Central -Andes, (2) their persistent development upon rocks of whatever structure -or degree of hardness, and (3) their present great elevation in spite of -moderate grades indicative of their development at a much lower -altitude. Mature slopes of equivalent form are developed in widely -separated localities in the Central Andes: in every valley about -Cochabamba, Bolivia, at 10,000 feet (3,050 m.); at Crucero Alto in -southern Peru at 14,600 feet (4,450 m.); several hundred miles farther -north at Anta near Cuzco, 11,000 feet to 12,000 feet (3,600 to 3,940 -m.), and Fig. 129 shows typical conditions in the Vilcabamba Valley -along the route of the Yale Peruvian Expedition of 1911. The -characteristic slopes so clearly represented in these four photographs -are the most persistent topographic elements in the physiography of the -Central Andes. - -[Illustration: FIG. 127--Topographic profiles across typical valleys of -southern Peru. They are drawn to scale and the equality of gradient of -the gentler upper slopes is so close that almost any curve would serve -as a composite of the whole. These curves form the basis of the diagram, -Fig. 128, whereby the amount of elevation of the Andes in late geologic -time may be determined. The approximate locations of the profiles are as -follows: 1, Antabamba; 2, Chuquibambilla; 3, upland south of Antabamba; -4, Apurimac Canyon above Pasaje; 5, Abancay; 6, Arma (Cordillera -Vilcapampa); 7, divide above Huancarama; 8, Huascatay; 9, Huasentay, -farther downstream; 10, Rio Pampas. The upper valley in 8 is still -undissected; 7 is practically the same; 8a is at the level which 8 must -reach before its side slopes are as gentle as at the end of the -preceding interrupted cycle.] - -The rock masses upon which the mature slopes were formed range from soft -to hard, from stratified shales, slates, sandstones, conglomerates, and -limestones to volcanics and intrusive granites. While these variations -impose corresponding differences of form, the graded quality of the -slopes is rarely absent. In some places the highly inclined strata are -shown thinly veiled with surface débris, yet so even as to appear -artificially graded. The rock in one place is hard granite, in another a -moderately hard series of lava flows, and again rather weak shales and -sandstones. - -Proof of the rapid and great uplift of certain now lofty mountain ranges -in late geologic time is one of the largest contributions of -physiography to geologic history. Its validity now rests upon a large -body of diversified evidence. In 1907 I crossed the Cordillera Sillilica -of Bolivia and northern Chile and came upon clear evidences of recent -and great uplift. The conclusions presented at that time were tested in -the region studied in 1911, 500 miles farther north, with the result -that it is now possible to state more precisely the dates of origin of -certain prominent topographic forms, and to reconstruct the conditions -which existed before the last great uplift in which the Central Andes -were born. The relation to this general problem of the forms under -discussion will now be considered. - -The gradients of the mature slopes, as we have already seen, are -distinctly moderate. In the Anta region, over an area several hundred -square miles in extent, they run from several degrees to 20° or 30°. -Ten-degree slopes are perhaps most common. If the now dissected slopes -be reconstructed on the basis of many clinometer readings, photographs, -and topographic maps, the result is a series of profiles as in Fig. 127. -If, further, the restored slopes be coördinated over an extensive area -the gradients of the resulting valley floors will run from 3° to 10°. -Finally, if these valley floors be extended westward to the Pacific and -eastward to the Amazon basin, they will be found about 5,000 feet above -sea level and 4,000 feet above the eastern plains. (For explanation of -method and data employed, see the accompanying figures 127-128). It is, -therefore, a justifiable conclusion that since the formation of the -slopes the Andes have been uplifted at least a mile, or, to put it in -another way, the Andes at the time of formation of the mature slopes -were at least a mile lower than they are at present. - -[Illustration: FIG. 128--Composition of slopes and profiles in the -Peruvian Andes. By superimposing the cross profiles of typical valleys -as shown in Fig. 127 a restoration is possible of the longitudinal -profiles of the earlier cycle of erosion. The difference in elevation of -the two profiles gives less than the minimum amount of uplift that must -have occurred. Case A represents a valley in which recent cutting has -not yet reached the valley head. Below the point 1 the profile has been -steepened and lowered by erosion in the current cycle. Above point 1 the -profile is still in the stage it reached in the preceding cycle. In case -B the renewed erosion of the current cycle has reached to the valley -head. Case C represents conditions similar to those in the preceding -cases save that the stream is typical of those that lie nearest the -steep flexed or faulted margins of the Cordillera and discharge to the -low levels of the desert pampa on the west or the tropical plains on the -east.] - -Further proof of recent and great uplift is afforded by the deeply -intrenched streams. After descending the long graded slopes one comes -upon the cliffed canyons with a feeling of consternation. The effect of -powerful erosion, incident upon uplift, is heightened by the ungraded -character of the river bed. Falls and rapids abound, the river profiles -suggest tumultuous descents, and much time will elapse before the river -beds have the regular and moderate gradients of the streams draining the -mature surface before uplift as shown in the profiles by the dotted -lines representing the restored valley floors of the older cycle. Since -the smooth-contoured landscape was formed great changes have taken -place. The streams have changed from completely graded to almost -completely ungraded profiles; in place of a subdued landscape we now -have upland slopes intersected by mile-deep canyons; the high-level -slopes could not have been formed under existing conditions, for they -are being dissected by the present streams. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM, DIRECTOR - -COTAHUASI QUADRANGLE - -(_La Cumbre_)] - -Since the slopes of the land in general undergo progressive changes in -the direction of flatter gradients during a given geographical cycle, it -follows that with the termination of one cycle and the beginning of -another, two sets of slopes will exist and that the gradients of the two -will be unlike. The result is a break in the descent of the slopes from -high to low levels to which the name "topographic unconformity" is now -applied. It will be a prominent feature of the landscape if the higher, -older, and flatter gradients have but little declivity, and the -gradients of the lower younger slopes are very steep. In those places -where the relief of the first cycle was still great at the time of -uplift, the erosion forms of the second cycle may not be differentiated -from those of the first, since both are marked by steep gradients. In -the Central Andes the change in gradient between the higher and lower -slopes is generally well marked. It occurs at variable heights above -the valley floors, though rarely more than 3,000 feet above them. In the -more central tracts, far from the main streams and their associated -canyons, dissection in the present erosion cycle has not yet been -initiated, the mature slopes are still intact, and a topographic -unconformity has not yet been developed. The higher slopes are faced -with rock and topped with slowly moving waste. Ascent of the spur end is -by steep zigzag trails; once the top is gained the trail runs along the -gentler slopes without special difficulties. - -It is worth noting at this point that the surface of erosion still older -than the mature slopes herewith described appears not to have been -developed along the seventy-third meridian of Peru, or if developed at -one time, fragments of it no longer remain. The last well-developed -remnant is southwest of Cuzco, Fig. 130. I have elsewhere described the -character and geographic distribution of this oldest recognizable -surface of the Central Andes.[41] Southern Peru and Bolivia and northern -Chile display its features in what seems an unmistakable manner. The -best locality yet found is in the Desaguadero Valley between Ancoaqui -and Concordia. There one may see thousands of feet of strongly inclined -sediments of varying resistance beveled by a well-developed surface of -erosion whose preserval is owing to a moderate rainfall and to location -in an interior basin.[42] - -The highest surface of a region, if formed during a prolonged period of -erosion, becomes a surface of reference in the determination of the -character and amount of later crustal deformations, having somewhat the -same functions as a key bed in stratigraphic geology. Indeed, concrete -physiographic facts may be the _only_ basis for arguments as to both -epeirogenic and orogenic movements. The following considerations may -show in condensed form the relative value of physiographic evidence: - -1. If movements in the earth's crust are predominantly _downward_, -sedimentation may be carried on continuously, and a clear geologic -record may be made. - -2. Even if crustal movements are alternately downward and upward, -satisfactory conclusions may be drawn from both (a) the nature of the -buried surfaces of erosion, and (b) the alternating character of the -sediments. - -3. If, however, the deformative processes effect steady or intermittent -uplifts, there may be no sediments, at least within the limits of the -positive crustal units, and a geologic record must be derived not from -sedimentary deposits but from topographic forms. We speak of the _lost -intervals_ represented by stratigraphic breaks or unconformities and -commonly emphasize our ignorance concerning them. The longest, and, from -the human standpoint, the most important, break in the sedimentary -record is that of the present wherever degradation is the predominant -physiographic process. Unlike the others the _lost interval_ of the -present is not lost, if we may so put it, but is in our possession, and -may be definitely described as a concrete thing. It is the physiography -of today. - -Even where long-buried surfaces of erosion are exposed to view, as in -northern Wisconsin, where the Pre-Cambrian paleo-plain projects from -beneath the Paleozoic sediments, or, as in New Jersey and southeastern -Pennsylvania, where the surface developed on the crystalline rocks -became by depression the floor of the Triassic and by more recent uplift -and erosion has been exposed to view,--even in such cases the exposures -are of small extent and give us at best but meager records. In short, -many of the breaks in the geologic record are of such long duration as -to make imperative the use of physiographic principles and methods. The -great Appalachian System of eastern North America has been a land area -practically since the end of the Paleozoic. In the Central Andes the -"lost interval," from the standpoint of the sedimentary, record, dates -from the close of the Cretaceous, except in a few local intermont basins -partially filled with Tertiary or Pleistocene deposits. Physiographic -interpretations, therefore, serve the double purpose of supplying a part -of the geologic record while at the same time forming a basis for the -scientific study of the surface distribution of living forms. - -The geologic dates of origin of the principal topographic forms of the -Central Andes may be determined with a fair degree of accuracy. Geologic -studies in Peru and Bolivia have emphasized the wide distribution of the -Cretaceous formations. They consist principally of thick limestones -above and sandstones and conglomerates below, and thus represent -extensive marine submergence of the earth's crust in the Cretaceous -where now there are very lofty mountains. The Cretaceous deposits are -everywhere strongly deformed or uplifted to a great height, and all have -been deeply eroded. They were involved, together with other and much -older sediments, in the erosion cycle which resulted in the development -of the widely extended series of mature slopes already described. From -low scattered island elevations projecting above sea level, as in the -Cretaceous period, the Andes were transformed by compression and uplift -to a rugged mountain belt subjected to deep and powerful erosion. The -products of erosion were in part swept into the adjacent seas, in part -accumulated on the floors of intermont basins, as in the great interior -basins of Titicaca and Poopó. - -Since the early Tertiary strata are themselves deformed from once simple -and approximately horizontal structures and subjected to moderate -tilting and faulting, it follows that mountain-making movements again -affected the region during later Tertiary. They did not, however, -produce extreme effects. They did stimulate erosion and bring about a -reorganization of all the slopes with respect to the new levels. - -This agrees closely with a second line of evidence which rests upon an -independent basis. The alluvial fill which lies upon all the canyon and -valley floors is of glacial origin, as shown by its interlocking -relations with morainal deposits at the valley heads. It is now in -process of dissection and since its deposition in the Pleistocene had -been eroded on the average about 200 feet. Clearly, to form a 3,000-foot -canyon in hard rock requires much more time than to deposit and again -partially to excavate an alluvial fill several hundred feet deep. -Moreover, the glacial material is coarse throughout, and was built up -rapidly and dissected rapidly. In most cases, furthermore, coarse -material at the bottom of the glacial series rests directly upon the -rock of a narrow and ungraded valley floor. From these and allied facts -it is concluded that there is no long time interval represented by the -transitions from degrading to aggrading processes and back again. The -early Pleistocene, therefore, seems quite too short a period in which to -produce the bold forms and effect the deep erosion which marks the -period between the close of the mature cycle and the beginnings of -deposition in the Pleistocene. - -The alternative conclusion is that the greater part of the canyon -cutting was effected in the late Tertiary, and that it continued into -the early Pleistocene until further erosion was halted by changed -climatic conditions and the augmented delivery of land waste to all the -streams. The final development of the well-graded high-level slopes is, -therefore, closely confined to a small portion of the Tertiary. The -closest estimate which the facts support appears to be Miocene or early -Pliocene. It is clear, however, that only the culmination of the period -can be definitely assigned. Erosion was in full progress at the close of -the Cretaceous and by middle Tertiary had effected vast changes in the -landscape. The Tertiary strata are marked by coarse basal deposit and by -thin and very fine top deposits. Though their deformed condition -indicates a period of crustal disturbance, the Tertiary beds give no -indication of wholesale transformations. They indicate chiefly tilting -and moderate and normal faulting. The previously developed effects of -erosion were, therefore, not radically modified. The surface was thus in -large measure prepared by erosion in the early Tertiary for its final -condition of maturity reached during the early Pliocene. - -It seems appropriate, in concluding this chapter, to summarize in its -main outlines the physiography of southern Peru, partly to condense the -extended discussion of the preceding paragraphs, and partly to supply a -background for the three chapters that follow. The outstanding features -are broad plateau areas separated by well-defined "Cordilleras." The -plateau divisions are not everywhere of the same origin. Those southwest -of Cuzco (Fig. 130), and in the Anta Basin (Fig. 124), northwest of -Cuzco, are due to prolonged erosion and may be defined as peneplane -surfaces uplifted to a great height. They are now bordered on the one -hand by deep valleys and troughs and basins of erosion and deformation; -and, on the other hand, by residual elevations that owe their present -topography to glacial erosion superimposed upon the normal erosion of -the peneplane cycle. The residuals form true mountain chains like the -Cordillera Vilcanota and Cordillera Vilcapampa; the depressions due to -erosion or deformation or both are either basins like those of Anta and -Cuzco or valleys of the canyon type like the Urubamba canyon; the -plateaus are broad rolling surfaces, the punas of the Peruvian Andes. - -There are two other types of plateaus. The one represents a mature stage -in the erosion cycle instead of an ultimate stage; the other is volcanic -in origin. The former is best developed about Antabamba (Figs. 122 and -123), where again deep canyons and residual ranges form the borders of -the plateau remnants. The latter is well developed above Cotahuasi and -in its simplest form is represented in Fig. 133. Its surface is the top -of a vast accumulation of lavas in places over a mile thick. While rough -in detail it is astonishingly smooth in a broad view (Fig. 29). Above it -rise two types of elevations: first, isolated volcanic cones of great -extent surrounded by huge lava flows of considerable relief; and second, -discontinuous lines of peaks where volcanic cones of less extent are -crowded closely together. The former type is displayed on the Coropuna -Quadrangle, the latter on the Cotahuasi and La Cumbre Quadrangles. - -So high is the elevation of the lava plateau, so porous its soil, so dry -the climate, that a few through-flowing streams gather the drainage of a -vast territory and, as in the Grand Canyon country of our West, they -have at long intervals cut profound canyons. The Arma has cut a deep -gorge at Salamanca; the Cotahuasi runs in a canyon in places 7,000 feet -deep; the Majes heads at the edge of the volcanic field in a steep -amphitheatre of majestic proportions. - -Finally, we have the plateaus of the coastal zone. These are plains with -surfaces several thousand feet in elevation separated by gorges several -thousand feet deep. The Pampa de Sihuas is an illustration. The -post-maturely dissected Coast Range separates it from the sea. The -pampas are in general an aggradational product formed in a past age -before uplift initiated the present canyon cycle of erosion. Other -plateaus of the coastal zone are erosion surfaces. The Tablazo de Ica -appears to be of this type. That at Arica, Chile, near the southern -boundary of Peru, is demonstrably of this type with a border on which -marine planation has in places given rise to a broad terrace -effect.[43] - - - - -CHAPTER XII - -THE WESTERN ANDES: THE MARITIME CORDILLERA OR CORDILLERA OCCIDENTAL - - -The Western or Maritime Cordillera of Peru forms part of the great -volcanic field of South America which extends from Argentina to Ecuador. -On the walls of the Cotahuasi Canyon (Fig. 131), there are exposed over -one hundred separate lava flows piled 7,000 feet deep. They overflowed a -mountainous relief, completely burying a limestone range from 2,000 to -4,000 feet high. Finally, upon the surface of the lava plateau new -mountains were formed, a belt of volcanoes 5,000 feet (1,520 m.) high -and from 15,000 to 20,000 feet (4,570 to 6,100 m.) above the sea. There -were vast mud flows, great showers of lapilli, dust, and ashes, and with -these violent disturbances also came many changes in the drainage. Sixty -miles northeast of Cotahuasi the outlet of an unnamed deep valley was -blocked, a lake was formed, and several hundred feet of sediments were -deposited. They are now wasting rapidly, for they lie in the zone of -alternate freezing and thawing, a thousand feet and more below the -snowline. Some of their bad-land forms look like the solid bastions of -an ancient fortress, while others have the delicate beauty of a Japanese -temple. - -Not all the striking effects of vulcanism belong to the remote geologic -past. A day's journey northeast of Huaynacotas are a group of lakes only -recently hemmed in by flows from the small craters thereabouts. The -fires in some volcanic craters of the Peruvian Andes are still active, -and there is no assurance that devastating flows may not again inundate -the valleys. In the great Pacific zone or girdle of volcanoes the -earth's crust is yet so unstable that earthquakes occur every year, and -at intervals of a few years they have destructive force. Cotahuasi was -greatly damaged in 1912; Abancay is shaken every few years; and the -violent earthquakes of Cuzco and Arequipa are historic. - -On the eastern margin of the volcanic country the flows thin out and -terminate on the summit of a limestone (Cretaceous) plateau. On the -western margin they descend steeply to the narrow west-coast desert. The -greater part of the lava dips beneath the desert deposits; there are a -few intercalated flows in the deposits themselves, and the youngest -flows--limited in number--have extended down over the inner edge of the -desert. - -The immediate coast of southern Peru is not volcanic. It is composed of -a very hard and ancient granite-gneiss which forms a narrow coastal -range (Fig. 171). It has been subjected to very long and continued -erosion and now exhibits mature erosion forms of great uniformity of -profile and declivity. - -From the outcrops of older rocks beneath the lavas it is possible to -restore in a measure the pre-volcanic topography of the Maritime -Cordillera, In its present altitude it ranges from several thousand to -15,000 feet above sea level. The unburied topography has been smoothed -out; the buried topography is rough (Figs. 29 and 166). The contact -lines between lavas and buried surfaces in the deep Majes and Cotahuasi -valleys are in places excessively serrate. From this, it seems safe to -conclude that the period of vulcanism was so prolonged that great -changes in the unburied relief were effected by the agents of erosion. -Thus, while the dominant process of volcanic upbuilding smoothed the -former rough topography of the Maritime Cordillera, erosion likewise -measurably smoothed the present high extra-volcanic relief in the -central and eastern sections. The effect has been to develop a broad and -sufficiently smooth aspect to the summit topography of the entire Andes -to give them a plateau character. Afterward the whole mountain region -was uplifted about a mile above its former level so that at present it -is also continuously lofty. - -The zone of most intense volcanic action does not coincide with the -highest part of the pre-volcanic topography. If the pre-volcanic relief -were even in a very general way like that which would be exhibited if -the lavas were now removed, we should have to say that the chief -volcanic outbursts took place on the western flank of an old and deeply -dissected limestone range. - -[Illustration: FIG. 129--Composition of slopes at Puquiura, Vilcabamba -Valley, elevation 9,000 feet (2,740 m.). The second prominent spur -entering the valley on the left has a flattish top unrelated to the rock -structure. Like the spurs on the right its blunt end and flat top -indicate an earlier erosion cycle at a lower elevation.] - -[Illustration: FIG. 130--Inclined Paleozoic strata truncated by an -undulating surface of erosion at 15,000 feet, southwest of Cuzco.] - -[Illustration: FIG. 131--Terraced valley slopes at Huaynacotas, -Cotahuasi Valley, at 11,500 feet (3,500 m.). Solimana is in the -background. On the floor of the Cotahuasi Canyon fruit trees grow. At -Huaynacotas corn and potatoes are the chief products. The section is -composed almost entirely of lava. There are over a hundred major flows -aggregating 5,000 to 7,000 feet thick.] - -The volume of the lavas is enormous. They are a mile and a half thick, -nearly a hundred miles wide, and of indefinite extent north and south. -Their addition to the Andes, therefore, _has greatly broadened the zone -of lofty mountains_. Their passes are from 2,000 to 3,000 feet higher -than the passes of the eastern Andes. They have a much smaller number of -valleys sufficiently deep to enjoy a mild climate. Their soil is far -more porous and dry. Their vegetation is more scanty. They more than -double the difficulties of transportation. And, finally, their all but -unpopulated loftier expanses are a great vacant barrier between farms in -the warm valleys of eastern Peru and the ports on the west coast. - -The upbuilding process was not, of course, continuous. There were at -times intervals of quiet, and some of them were long enough to enable -streams to become established. Buried valleys may be observed in a -number of places on the canyon walls, where subsequently lava flows -displaced the streams and initiated new drainage systems. In these quiet -intervals the weathering agents attacked the rock surfaces and formed -soil. There were at least three or four such prolonged periods of -weathering and erosion wherein a land surface was exposed for many -thousands of years, stream systems organized, and a cultivable soil -formed. No evidence has been found, however, that man was there to -cultivate the soil. - -The older valleys cut in the quiet period are mere pygmies beside the -giant canyons of today. The present is the time of dominant erosion. The -forces of vulcanism are at last relatively quiet. Recent flows have -occurred, but they are limited in extent and in effects. They alter only -the minor details of topography and drainage. Were it not for the oases -set in the now deep-cut canyon floors, the lava plateau of the Maritime -Cordillera would probably be the greatest single tract of unoccupied -volcanic country in the world. - -The lava plateau has been dissected to a variable degree. Its high -eastern margin is almost in its original condition. Its western margin -is only a hundred miles from the sea, so that the streams have steep -gradients. In addition, it is lofty enough to have a moderate rainfall. -It is, therefore, deeply and generally dissected. Within the borders of -the plateau the degree of dissection depends chiefly upon position with -respect to the large streams. These were in turn located in an -accidental manner. The repeated upbuilding of the surface by the -extensive outflow of liquid rock obliterated all traces of the earlier -drainage. In the Cotahuasi Canyon the existing stream, working down -through a mile of lavas, at last uncovered and cut straight across a -mountain spur 2,000 feet high. Its course is at right angles to that -pursued by the stream that once drained the spur. It is noteworthy that -the Cotahuasi and adjacent streams take northerly courses and join -Atlantic rivers. The older drainage was directly west to the Pacific. -Thus, vulcanism not only broadened the Andes and increased their height, -but also moved the continental divide still nearer the west coast. - -The glacial features of the western or Maritime Cordillera are of small -extent, partly because vulcanism has added a considerable amount of -material in post-glacial time, partly because the climate is so -exceedingly dry that the snowline lies near the top of the country. The -slopes of the volcanic cones are for the most part deeply recessed on -the southern or shady sides. Above 17,500 feet (5,330 m.) the process of -snow and ice excavation still continues, but the tracts that exceed this -elevation are confined to the loftiest peaks or their immediate -neighborhood. There is a distinct difference between the glacial forms -of the eastern or moister and the western or dryer flanks of this -Cordillera. Only peaks like Coropuna and Solimana near the western -border now bear or ever bore snowfields and glaciers. By contrast the -eastern aspect is heavily glaciated. On La Cumbre Quadrangle, there is a -huge glacial trough at 16,000 feet (4,876 m.), and this extends with -ramifications up into the snowfields that formerly included the highest -country. Prolonged glacial erosion produced a full set of topographic -forms characteristic of the work of Alpine glaciers. Thus, each of the -main mountain chains that make up the Andean system has, like the system -as a whole, a relatively more-dry and a relatively less-dry aspect. The -snowline is, therefore, canted from west to east on each chain as well -as on the system. However, this effect is combined with a solar effect -in an unequal way. In the driest places the solar factor is the more -efficient and the snowline is there canted from north to south. - - - - -CHAPTER XIII - -THE EASTERN ANDES: THE CORDILLERA VILCAPAMPA - - -The culminating range of the eastern Andes is the so-called Cordillera -Vilcapampa. Its numerous, sharp, snow-covered peaks are visible in every -summit view from the central portion of the Andean system almost to the -western border of the Amazon basin. Though the range forms a water -parting nearly five hundred miles long, it is crossed in several places -by large streams that flow through deep canyons bordered by precipitous -cliffs. The Urubamba between Torontoy and Colpani is the finest -illustration. For height and ruggedness the Vilcapampa mountains are -among the most noteworthy in Peru. Furthermore, they display glacial -features on a scale unequaled elsewhere in South America north of the -ice fields of Patagonia. - - -GLACIERS AND GLACIAL FORMS - -One of the most impressive sights in South America is a tropical forest -growing upon a glacial moraine. In many places in eastern Bolivia and -Peru the glaciers of the Ice Age were from 5 to 10 miles long--almost -the size of the Mer de Glace or the famous Rhone glacier. In the Juntas -Valley in eastern Bolivia the tree line is at 10,000 feet (3,050 m.), -but the terminal moraines lie several thousand feet lower. In eastern -Peru the glaciers in many places extended down nearly to the tree line -and in a few places well below it. In the Cordillera Vilcapampa vast -snowfields and glacier systems were spread out over a summit area as -broad as the Southern Appalachians. The snowfields have since shrunk to -the higher mountain recesses; the glaciers have retreated for the most -part to the valley heads or the cirque floors; and the lower limit of -perpetual snow has been raised to 15,500 feet. - -[Illustration: FIG. 132--Recessed volcanoes in the right background and -eroded tuffs, ash beds, and lava flows on the left. Maritime Cordillera -above Cotahuasi.] - -[Illustration: FIG. 133--The summit of the great lava plateau above -Cotahuasi on the trail to Antabamba. The lavas are a mile and a half in -thickness. The elevation is 16,000 feet. Hence the volcanoes in the -background, 17,000 feet above sea level, are mere hills on the surface -of the lofty plateau.] - -[Illustration: FIG. 134--Southwestern aspect of the Cordillera -Vilcapampa between Anta and Urubamba from Lake Huaipo. Rugged summit -topography in the background, graded post-mature slopes in the middle -distance, and solution lake in limestone in the foreground.] - -[Illustration: FIG. 135--Summit view, Cordillera Vilcapampa. There are -fifteen glaciers represented in this photograph. The camera stands on -the summit of a minor divide in the zone of nivation.] - -These features are surprising because neither Whymper[44] nor Wolf[45] -mentions the former greater extent of the ice on the volcanoes of -Ecuador, only ten or twelve degrees farther north. Moreover, Reiss[46] -denies that the hypothesis of universal climatic change is supported by -the facts of a limited glaciation in the High Andes of Ecuador; and J. -W. Gregory[47] completely overlooks published proof of the existence of -former more extensive glaciers elsewhere in the Andes: - -"... the absence not only of any traces of former more extensive -glaciation from the tropics, as in the Andes and Kilimandjaro, but also -from the Cape." He says further: "In spite of the extensive glaciers now -in existence on the higher peaks of the Andes, there is practically no -evidence of their former greater extension."(!) - -Whymper spent most of his time in exploring recent volcanoes or those -recently in eruption, hence did not have the most favorable -opportunities for gathering significant data. Reiss was carried off his -feet by the attractiveness of the hypothesis[48] relating to the effect -of glacial denudation on the elevation of the snowline. Gregory appeared -not to have recognized the work of Hettner on the Cordillera of Bogotá -and of Sievers[49] and Acosta on the Sierra Nevada de Santa Marta in -northern Colombia. - -The importance of the glacial features of the Cordillera Vilcapampa -developed on a great scale in very low latitudes in the southern -hemisphere is twofold: first, it bears on the still unsettled problem of -the universality of a colder climate in the Pleistocene, and, second, it -supplies additional data on the relative depression of the snowline in -glacial times in the tropics. Snow-clad mountains near the equator are -really quite rare. Mount Kenia rising from a great jungle on the -equator, Kilimandjaro with its two peaks, Kibo and Mawenzi, two hundred -miles farther south, and Ingomwimbi in the Ruwenzori group thirty miles -north of the equator, are the chief African examples. A few mountains -from the East Indies, such as Kinibalu in Borneo, latitude 6° north, -have been found glaciated, though now without a snow cover. In higher -latitudes evidences of an earlier extensive glaciation have been -gathered chiefly from South America, whose extension 13° north and 56° -south of the equator, combined with the great height of its dominating -Cordillera, give it unrivaled distinction in the study of mountain -glaciation in the tropics. - -Furthermore, mountain summits in tropical lands are delicate climatic -registers. In this respect they compare favorably with the inclosed -basins of arid regions, where changes in climate are clearly recorded in -shoreline phenomena of a familiar kind. Lofty mountains in the tropics -are in a sense inverted basins, the lower snowline of the past is like -the higher shoreline of an interior basin; the terminal moraines and the -alluvial fans in front of them are like the alluvial fans above the -highest strandline; the present snow cover is restricted to mountain -summits of small areal extent, just as the present water bodies are -restricted to the lowest portions of the interior basin; and successive -retreatal stages are marked by terminal moraines in the one case as they -are marked in the other by flights of terraces and beach ridges. - -I made only a rapid reconnaissance across the Cordillera Vilcapampa in -the winter season, and cannot pretend from my limited observations to -solve many of the problems of the field. The data are incorporated -chiefly in the chapter on Glacial Features. In this place it is proposed -to describe only the more prominent glacial features, leaving to later -expeditions the detailed descriptions upon which the solution of some of -the larger problems must depend. - -At Choquetira three prominent stages in the retreat of the ice are -recorded. The lowermost stage is represented by the great fill of -morainic and outwash material at the junction of the Choquetira, and an -unnamed valley farther south at an elevation of 11,500 feet (3,500 m.). -A mile below Choquetira a second moraine appears, elevation 12,000 feet -(3,658 m.), and immediately above the village a third at 12,800 (3,900 -m.). The lowermost moraine is well dissected, the second is ravined and -broken but topographically distinct, the third is sharp-crested and -regular. A fourth though minor stage is represented by the moraine at -the snout of the living glacier and still less important phases are -represented in some valleys--possibly the record of post-glacial changes -of climate. Each main moraine is marked by an important amount of -outwash, the first and third moraines being associated with the greatest -masses. The material in the moraines represents only a part of that -removed to form the successive steps in the valley profile. The -lowermost one has an enormous volume, since it is the oldest and was -built at a time when the valley was full of waste. It is fronted by a -deep fill, over the dissected edge of which one may descend 800 feet in -half an hour. It is chiefly alluvial in character, whereas the next -higher one is composed chiefly of bowlders and is fronted by a -pronounced bowlder train, which includes a remarkable perched bowlder of -huge size. Once the valley became cleaned out the ice would derive its -material chiefly by the slower process of plucking and abrasion, hence -would build much smaller moraines during later recessional stages, even -though the stages were of equivalent length. - -[Illustration: FIG. 136--Glacial sculpture on the southwestern flank of -the Cordillera Vilcapampa. Flat-floored valleys and looped terminal -moraines below and glacial steps and hanging valleys are characteristic. -The present snowfields and glaciers are shown by dotted contours.] - -There is a marked difference in the degree of dissection of the -moraines. The lowermost and oldest is so thoroughly dissected as to -exhibit but little of its original surface. The second has been greatly -modified, but still possesses a ridge-like quality and marks the -beginning of a noteworthy flattening of the valley gradient. The third -is as sharp-crested as a roof, and yet was built so long ago that the -flat valley floor behind it has been modified by the meandering stream. -From this point the glacier retreated up-valley several miles -(estimated) without leaving more than the thinnest veneer on the valley -floor. The retreat must, therefore, have been rapid and without even -temporary halts until the glacier reached a position near that occupied -today. Both the present ice tongues and snowfields and those of a past -age are emphasized by the presence of a patch of scrub and woodland that -extends on the north side of the valley from near the snowline down over -the glacial forms to the lower valley levels. - -The retreatal stages sketched above would call for no special comment if -they were encountered in mountains in northern latitudes. They would be -recognized at once as evidence of successive periodic retreats of the -ice, due to successive changes in temperature. To understand their -importance when encountered in very low latitudes it is necessary to -turn aside for a moment and consider two rival hypotheses of glacial -retreat. First we have the hypothesis of periodic retreat, so generally -applied to terminal moraines and associated outwash in glaciated -mountain valleys. This implies also an advance of the ice from a higher -position, the whole taking place as a result of a climatic change from -warmer to colder and back again to warmer. - -[Illustration: FIG. 137--Looking up a spurless flat-floored glacial -trough near the Chucuito pass in the Cordillera Vilcapampa from 14,200 -feet (4,330 m.). Note the looped terminal and lateral moraines on the -steep valley wall on the left. A stone fence from wall to wall serves to -inclose the flock of the mountain shepherd.] - -[Illustration: FIG. 138--Terminal moraine in the glaciated Choquetira -Valley below Choquetira. The people who live here have an abundance of -stones for building corrals and stone houses. The upper edge of the -timber belt (cold timber line) is visible beyond the houses. Elevation -12,100 feet (3,690 m.).] - -But evidences of more extensive mountain glaciation in the past do not -in themselves prove a change in climate over the whole earth. In an -epoch of fixed climate a glacier system may so deeply and thoroughly -erode a mountain mass, that the former glaciers may either diminish in -size or disappear altogether. As the work of excavation proceeds, the -catchment basins are sunk to, and at last below, the snowline; broad -tributary spurs whose snows nourish the glaciers, may be reduced to -narrow or skeleton ridges with little snow to contribute to the valleys -on either hand; the glaciers retreat and at last disappear. There -would be evidences of glaciation all about the ruins of the former -loftier mountain, but there would be no living glaciers. And yet the -climate might remain the same throughout. - -It is this "topographic" hypothesis that Reiss and Stübel accept for the -Ecuadorean volcanoes. Moreover, the volcanoes of Ecuador are practically -on the equator--a very critical situation when we wish to use the facts -they exhibit in the solution of such large problems as the -contemporaneous glaciation of the two hemispheres, or the periodic -advance and retreat of the ice over the whole earth. This is not the -place to scrutinize either their facts or their hypothesis, but I am -under obligations to state very emphatically that the glacial features -of the Cordillera Vilcapampa require the climatic and not the -topographic hypothesis. Let us see why. - -The differences in degree of dissection and the flattening gradient -up-valley that we noted in a preceding paragraph leave no doubt that -each moraine of the bordering valleys in the Vilcapampa region, -represents a prolonged period of stability in the conditions of -topography as well as of temperature and precipitation. If change in -topographic conditions is invoked to explain retreat from one position -to the other there is left no explanation of the periodicity of retreat -which has just been established. If a period of cold is inaugurated and -glaciers advance to an ultimate position, they can retreat only through -change of climate effected either by general causes or by topographic -development to the point where the snowfields become restricted in size. -In the case of climatic change the ice changes are periodic. In the case -of retreat due to topographic change there should be a steady or -non-periodic falling back of the ice front as the catchment basins -decrease in elevation and the snow-gathering ridges tributary to them -are reduced in height. - -Further, the matterhorns of the Cordillera Vilcapampa are not bare but -snow-covered, vigorous glaciers several miles in length and large -snowfields still survive and the divides are not arêtes but broad -ridges. In addition, the last two moraines, composed of very loose -material, are well preserved. They indicate clearly that the time since -their formation has witnessed no wholesale topographic change. If (1) no -important topographic changes have taken place, and (2) a vigorous -glacier lay for a long period back of a given moraine, and (3) _suddenly -retreated several miles and again became stable_, we are left without -confidence in the application of the topographic hypothesis to the -glacial features of the Vilcapampa region. Glacial retreat may be -suddenly begun in the case of a late stage of topographic development, -but it should be an orderly retreat marked by a large number of small -moraines, or at least a plentiful strewing of the valley floor with -débris. - -[Illustration: FIG. 139--Glacial features on the eastern slopes of the -Cordillera Vilcapampa.] - -The number of moraines in the various glaciated valleys of the -Cordillera Vilcapampa differ, owing to differences in elevation and to -the variable size of the catchment basins. All valleys, however, display -the same sudden change from moraine to moraine and the same -characteristics of gradient. In all of them the lowermost moraine is -always more deeply eroded than the higher moraines, in all of them -glacial erosion was sufficiently prolonged greatly to modify the valley -walls, scour out lake basins, or broad flat valley floors, develop -cirques, arêtes, and pinnacled ridges in limited number. In some, -glaciation was carried to the point where only skeleton divides -remained, in most places broad massive ridges or mountain knots persist. -In spite of all these differences successive moraines were formed, -separated by long stretches either thinly covered with till or exposing -bare rock. - -In examining this group of features it is important to recognize the -essential fact that though the number of moraines varies from valley to -valley, the differences in character between the moraines at low and at -high elevations in a single valley are constant. It is also clear that -everywhere the ice retreated and advanced periodically, no matter with -what topographic features it was associated, whether those of maturity -or of youth in the glacial cycle. We, therefore, conclude that -topographic changes had no significant part to play in the glacial -variations in the Cordillera Vilcapampa. - -The country west of the Cordillera Vilcapampa had been reduced to early -topographic maturity before the Ice Age, and then uplifted with only -moderate erosion of the masses of the interfluves. That on the east had -passed through the same sequence of events, but erosion had been carried -much farther. The reason for this is found in a strong climatic -contrast. The eastern is the windward aspect and receives much more rain -than the western. Therefore, it has more streams and more rapid -dissection. The result was that the eastern slopes were cut to pieces -rapidly after the last great regional uplift; the broad interfluves were -narrowed to ridges. The region eastward from the crest of the Cordillera -to the Pongo de Mainique looks very much like the western half of the -Cascade Mountains in Oregon--the summit tracts of moderate declivity are -almost all consumed. - -The effect of these climatic and topographic contrasts is manifested in -strong contrasts in the position and character of the glacial forms on -the opposite slopes of the range. At Pampaconas on the east the -lowermost terminal moraine is at least a thousand feet below timber -line. Between Vilcabamba pueblo and Puquiura the terminal moraine lies -at 11,200 feet (3,414 m.). By contrast the largest Pleistocene glacier -on the western slope, nearly twelve miles long, and the largest along -the traverse, ended several miles below Choquetira at 11,500 feet (3,504 -m.) elevation, or just at the timber line. Thus, the steeper descents of -the eastern side of the range appear to have carried short glaciers to -levels far lower than those attained by the glaciers of the western -slope. - -It seems at first strange that the largest glaciers were west of the -divide between the Urubamba and the Apurimac, that is, on the relatively -dry side of the range. The reason lies in a striking combination of -topographic and climatic conditions. Snow is a mobile form of -precipitation that is shifted about by the wind like a sand dune in the -desert. It is not required, like water, to begin a downhill movement as -soon as it strikes the earth. Thus, it is a noteworthy fact that snow -drifting across the divides may ultimately cause the largest snowfields -to lie where the least snow actually falls. This is illustrated in the -Bighorns of Wyoming and others of our western ranges. It is, however, -not the wet snow near the snowline, but chiefly the dry snow of higher -altitudes that is affected. What is now the dry or leeward side of the -Cordillera appears in glacial times to have actually received more snow -than the wet windward side. - -[Illustration: FIG. 140--Glacial sculpture in the heart of the -Cordillera Vilcapampa. In places the topography has so high a relief -that the glaciers seem almost to overhang the valleys. See Figs. 96 and -179 for photographs.] - -The topography conspired to increase this contrast. In place of many -streams, direct descents, a dispersion of snow in many valleys, as on -the east, the western slopes had indirect descents, gentler valley -profiles, and that higher degree of concentration of drainage which -naturally goes with topographic maturity. For example, there is nothing -in the east to compare with the big spurless valley near the pass above -Arma. The side walls were so extensively trimmed that the valley was -turned into a trough. The floor was smoothed and deepened and all the -tributary glaciers were either left high up on the bordering slopes or -entered the main valley with very steep profiles; their lateral and -terminal moraines now hang in festoons on the steep side walls. -Moreover, the range crest is trimmed from the west so that the serrate -skyline is a feature rarely seen from eastern viewpoints. This may not -hold true for more than a small part of the Cordillera. It was probably -emphasized here less by the contrasts already noted than by the geologic -structure. The eastward-flowing glaciers descended over dip slopes on -highly inclined sandstones, as at Pampaconas. Those flowing westward -worked either in a jointed granite or on the outcropping _edges_ of the -sandstones, where the quarrying process known as glacial plucking -permitted the development of excessively steep slopes. - -There are few glacial steps in the eastern valleys. The western valleys -have a marvelous display of this striking glacial feature. The -accompanying hachure maps show them so well that little description is -needed. They are from 50 to 200 feet high. Each one has a lake at its -foot into which the divided stream trickles over charming waterfalls. -All of them are clearly associated with a change in the volume of the -glacier that carved the valley. Wherever a tributary glacier entered, or -the side slopes increased notably in area, a step was formed. By retreat -some of them became divided, for the process once begun would push the -step far up valley after the manner of an extinguishing waterfall. - -The retreat of the steps, the abrasion of the rock, and the sapping of -the cirques at the valley heads excavated the upper valleys so deeply -that they are nearly all, as W. D. Johnson has put it, "down at the -heel." Thus, above Arma, one plunges suddenly from the smooth, grassy -glades of the strongly glaciated valley head down over the outer slopes -of the lowermost terminal moraine to the steep lower valley. Above the -moraine are fine pastures, in the steep valley below are thickets and -rocky defiles. There are long quiet reaches in the streams of the -glaciated valley heads besides pretty lakes and marshes. Below, the -stream is swift, almost torrential. Arma itself is built upon alluvial -deposits of glacial origin. A mile farther down the valley is -constricted and steep-walled--really a canyon. - -Though the glaciers have retreated to the summit region, they are by no -means nearing extinction. The clear blue ice of the glacier descending -from Mt. Soiroccocha in the Arma Valley seems almost to hang over the -precipitous valley border. In curious contrast to its suggestion of cold -and storm is the patch of dark green woodland which extends right up to -its border. An earthquake might easily cause the glacier to invade the -woodland. Some of the glaciers between Choquetira and Arma rest on -terminal moraines whose distal faces are from 200 to 300 feet high. The -ice descending southeasterly from Panta Mt. is a good illustration. -Earlier positions of the ice front are marked by equally large moraines. -The one nearest that engaged by the living glacier confines a large lake -that discharges through a gap in the moraine and over a waterfall to the -marshy floor of the valley. - -Retreat has gone so far, however, that there are only a few large -glacier systems. Most of the tributaries have withdrawn toward their -snowfields. In place of the twenty distinct glaciers now lying between -the pass and the terminal moraine below Choquetira, there was in glacial -times one great glacier with twenty minor tributaries. The cirques now -partly filled with damp snow must then have been overflowing with dry -snow above and ice below. Some of the glaciers were over a thousand feet -thick; a few were nearly two thousand feet thick, and the cirques that -fed them held snow and ice at least a half mile deep. Such a remarkably -complete set of glacial features only 700 miles from the equator is -striking evidence of the moist climate on the windward eastern part of -the great Andean Cordillera, of the universal change in climate in the -glacial period, and of the powerful dominating effects of ice erosion in -this region of unsurpassed Alpine relief. - - -THE VILCAPAMPA BATHOLITH AND ITS TOPOGRAPHIC EFFECTS - -[Illustration: FIG. 141--Composite geologic section on the northeastern -border of the Cordillera Vilcapampa, in the vicinity of Pampaconas, to -show the deformative effects of the granite intrusion. There is a -limited amount of limestone near the border of the Cordillera. Both -limestone and sandstone are Carboniferous. See Appendix B. See also -Figs. 142 and 146. The section is about 15 miles long.] - -The main axis of the Cordillera Vilcapampa consists of granite in the -form of a batholith between crystalline schists on the one hand -(southwest), and Carboniferous limestones and sandstones and Silurian -shales and slates on the other (northeast). It is not a domal uplift in -the region in which it was observed in 1911, but an axial intrusion, in -places restricted to a narrow belt not more than a score of miles -across. As we should expect from the variable nature of the invaded -material, the granite belt is not uniform in width nor in the character -of its marginal features. In places the intrusion has produced -strikingly little alteration of the country rock; in other localities -the granite has been injected into the original material in so intimate -a manner as almost completely to alter it, and to give rise to a very -broad zone of highly metamorphosed rock. Furthermore, branches were -developed so that here and there tributary belts of granite extend from -the main mass to a distance of many miles. Outlying batholiths occur -whose common petrographic character and similar manner of occurrence -leave little doubt that they are related abyssally to a common plutonic -mass. - -The Vilcapampa batholith has two highly contrasted borders, whether we -consider the degree of metamorphism of the country rock, the definition -of the border, or the resulting topographic forms. On the northeastern -ridge at Colpani the contact is so sharp that the outstretched arms in -some places embrace typical granite on the one hand and almost -unaltered shales and slates on the other. Inclusions or xenoliths of -shale are common, however, ten and fifteen miles distant, though they -are prominent features in a belt only a few miles wide. The lack of more -intense contact effects is a little remarkable in view of the altered -character of the inclusions, all of which are crystalline in contrast to -the fissile shales from which they are chiefly derived. Inclusions -within a few inches of the border fall into a separate class, since they -show in general but trifling alteration and preserve their original -cleavage plains. It appears that the depth of the intrusion must have -been relatively slight or the intrusion sudden, or both shallow and -sudden, conditions which produce a narrow zone of metamorphosed material -and a sharp contact. - -[Illustration: FIG. 142--The deformative effects of the Vilcapampa -intrusion on the northeastern border of the Cordillera. The deformed -strata are heavy-bedded sandstones and shales and the igneous rocks are -chiefly granites with bordering porphyries. Looking northwest near -Puquiura. For conditions near Pampaconas, looking in the opposite -direction, see Fig. 141. For conditions on the other side of the -Cordillera, see Fig. 146.] - -The relation between shale and granite at Colpani is shown in Fig. 143. -Projections of granite extend several feet into the shale and slate and -generally end in blunt barbs or knobs. In a few places there is an -intimate mixture of irregular slivers and blocks of crystallized -sediments in a granitic groundmass, with sharp lines of demarcation -between igneous and included material. The contact is vertical for at -least several miles. It is probable that other localities on the contact -exhibit much greater modification and invasion of the weak shales and -slates, but at Colpani the phenomena are both simple and restricted in -development. - -[Illustration: FIG. 143--Relation of granite intrusion to schist on the -northeastern border of the Vilcapampa batholith near the bridge of -Colpani, lower end of the granite Canyon of Torontoy. The sections are -from 15 to 25 feet high and represent conditions at different levels -along the well-defined contact.] - -The highly mineralized character of the bordering sedimentary strata, -and the presence of numbers of complementary dikes, nearly identical in -character to those in the parent granite now exposed by erosion over a -broad belt roughly parallel to the contact, supplies a basis for the -inference that the granite may underlie the former at a slight depth, or -may have had far greater metamorphic effects upon its sedimentary roof -than the intruded granite has had upon its sedimentary rim. - -The physiographic features of the contact belt are of special interest. -No available physiographic interpretation of the topography of a -batholith includes a discussion of those topographic and drainage -features that are related to the lithologic character of the intruded -rock, the manner of its intrusion, or the depth of erosion since -intrusion. Yet each one of these factors has a distinct topographic -effect. We shall, therefore, turn aside for a moment from the detailed -discussion of the Vilcapampa region to an examination of several -physiographic principles and then return to the main theme for -applications. - -It is recognized that igneous intrusions are of many varieties and that -even batholithic invasions may take place in rather widely different -ways. Highly heated magmas deeply buried beneath the earth's surface -produce maximum contact effects, those nearer the surface may force the -strata apart without extreme lithologic alterations of the displaced -beds, while through the stoping process a sedimentary cover may be -largely absorbed and the magmas may even break forth at the surface as -in ordinary vulcanism. If the sedimentary beds have great vertical -variation in resistance, in attitude, and in composition, there may be -afforded an opportunity for the display of quite different effects at -different levels along a given contact, so that a great variety of -physical conditions will be passed by the descending levels of erosion. -At one place erosion may have exposed only the summit of the batholith, -at another the associated dikes and sheets and ramifying branches may be -exposed as in the zone of fracture, at a third point the original zone -of flowage may be reached with characteristic marginal schistosity, -while at still greater depths there may be uncovered a highly -metamorphosed rim of resistant sedimentary rock. - -The mere enumeration of these variable structural features is sufficient -to show how variable we should expect the associated land forms to be. -Were the forms of small extent, or had they but slight distinction upon -comparison with other erosional effects, they would be of little -concern. They are, on the contrary, very extensively developed; they -affect large numbers of lofty mountain ranges besides still larger areas -of old land masses subjected to extensive and deep erosion, thus laying -bare many batholiths long concealed by a thick sedimentary roof. - -The differences between intruded and country rock dependent upon these -diversified conditions of occurrence are increased or diminished -according to the history of the region after batholithic invasion takes -place. Regional metamorphism may subsequently induce new structures or -minimize the effects of the old. Joint systems may be developed, the -planes widely spaced in one group of rocks giving rise to monolithic -masses very resistant to the agents of weathering, while those of an -adjacent group may be so closely spaced as greatly to hasten the rate of -denudation. There may be developed so great a degree of schistosity in -one rock as to give rise (with vigorous erosion) to a serrate -topography; on the other hand the forms developed on the rocks of a -batholith may be massive and coarse-textured. - -To these diversifying conditions may be added many others involving a -large part of the field of dynamic geology. It will perhaps suffice to -mention two others: the stage of erosion and the special features -related to climate. If a given intrusion has been accompanied by an -important amount of uplift or marginal compression, vigorous erosion may -follow, whereupon a chance will be offered for the development of the -greatest contrast in the degree of boldness of topographic forms -developed upon rocks of unequal resistance. Ultimately these contrasts -will diminish in intensity, as in the case of all regional differences -of relief, with progress toward the end of the normal cycle of erosion. -If peneplanation ensue, only feeble topographic differences may mark -the line of contact which was once a prominent topographic feature. With -reference to the effects of climate it may be said simply that a granite -core of batholithic origin may extend above the snowline or above timber -line or into the timbered belt, whereas the invaded rock may occur -largely below these levels with obvious differences in both the rate and -the kind of erosion affecting the intruded mass. - -[Illustration: FIG. 144--Cliffed canyon wall in the Urubamba Valley -between Huadquiña and Torontoy. There is a descent of nearly 2,000 feet -shown in the photograph and it is developed almost wholly along -successive joint planes.] - -[Illustration: FIG. 145--Another aspect of the canyon wall of Fig. 144. -The almost sheer descents are in contrast with the cliff and platform -type of topography characteristic of the Grand Canyon of Colorado.] - -If we apply the foregoing considerations to the Cordillera Vilcapampa, -we shall find some striking illustrations of the principles involved. -The invasion of the granite was accompanied by moderate absorption of -the displaced rock, and more especially by the marginal pushing aside of -the sedimentary rim. The immediate effect must have been to give both -intruded rock and country rock greater height and marked ruggedness. -There followed a period of regional compression and torsion, and the -development of widespread joint systems with strikingly regular -features. In the Silurian shales and slates these joints are closely -spaced; in the granites they are in many places twenty to thirty feet -apart. The shales, therefore, offer many more points of attack and have -weathered down into a smooth-contoured topography boldly overlooked -along the contact by walls and peaks of granite. _In some cases a canyon -wall a mile high is developed entirely on two or three joint planes -inclined at an angle no greater than 15°._ The effect in the granite is -to give a marked boldness of relief, nowhere more strikingly exhibited -than at Huadquiña, below Colpani, where the foot-hill slopes developed -on shales and slates suddenly become moderate. The river flows from a -steep and all but uninhabited canyon into a broad valley whose slopes -are dotted with the terraced _chacras_, or farms, of the mountain -Indians. - -The Torontoy granite is also homogeneous while the shales and slates -together with their more arenaceous associates occur in alternating -belts, a diversity which increases the points of attack and the -complexity of the forms. Tending toward the same result is the greater -hardness of the granite. The tendency of the granite to develop bold -forms is accelerated in lofty valleys disposed about snow-clad peaks, -where glaciers of great size once existed, and where small glaciers -still linger. The plucking action of ice has an excellent chance for -expression, since the granite may be quarried cleanly without the -production of a large amount of spoil which would load the ice and -diminish the intensity of its plucking action. - -As a whole the Central Andes passed through a cycle of erosion in late -Tertiary time which was interrupted by uplift after the general surface -had been reduced to a condition of topographic maturity. Upon the -granites mature slopes are not developed except under special conditions -(1) of elevation as in the small batholith above Chuquibambilla, and (2) -where the granite is itself bordered by resistant schists which have -upheld the surface over a broad transitional belt. Elsewhere the granite -is marked by exceedingly rugged forms: deep steep-walled canyons, -precipitous cirques, matterhorns, and bold and extended escarpments of -erosion. In the shale belt the trails run from valley to valley in every -direction without special difficulties, but in the granite they follow -the rivers closely or cross the axis of the range by carefully selected -routes which generally reach the limit of perpetual snow. Added interest -attaches to these bold topographic forms because of the ruins now found -along the canyon walls, as at Torontoy, or high up on the summit of a -precipitous spur, as at Machu Picchu near the bridge of San Miguel. - -The Vilcapampa batholith is bordered on the southwest by a series of -ancient schists with which the granite sustains quite different -relations. No sharp dividing line is visible, the granite extending -along the planes of foliation for such long distances as in places to -appear almost interbedded with the schists. The relation is all the more -striking in view of the trifling intrusions effected in the case of the -seemingly much weaker shales on the opposite contact. Nor is the -metamorphism of the invaded rock limited to simple intrusion. For -several miles beyond the zone of intenser effects the schists have been -enriched with quartz to such an extent that their original darker color -has been changed to light gray or dull white. At a distance they may -even appear as homogeneous and light-colored as the granite. At distant -points the schists assume a darker hue and take on the characters of a -rather typical mica schist. - -It is probable that the Vilcapampa intrusion is one of a family of -batholiths which further study may show to extend over a much larger -territory. The trail west of Abancay was followed quite closely and -accidentally crosses two small batholiths of peculiar interest. Their -limits were not closely followed out, but were accurately determined at -a number of points and the remaining portion of the contact inferred -from the topography. In the case of the larger area there may indeed be -a connection westward with a larger mass which probably constitutes the -ranges distant some five to ten miles from the line of traverse. - -[Illustration: FIG. 146--Deformative effects on limestone strata of the -granite intrusion on the southwestern border of the Vilcapampa batholith -above Chuquibambilla. Fig. 147 is on the same border of the batholith -several miles farther northwest. The granite mass on the right is a -small outlier of the main batholith looking south. The limestone is -Cretaceous. See Appendix C for locations.] - -These smaller intrusions are remarkable in that they appear to have been -attended by little alteration of either invading or invaded rock, though -the granites were observed to become distinctly more acid in the contact -zone. Space was made for them by displacing the sedimentary cover and by -a marked shortening of the sedimentary rim through such structures as -overthrust faults and folds. The contact is observable in a highly -metamorphosed belt about twenty feet wide, and for several hundred feet -more the granite has absorbed the limestone in small amounts with the -production of new minerals and the development of a distinctly lighter -color. The deformative effects of the batholithic invasion are shown in -their gross details in Figs. 141, 142, and 146; the finer details of -structure are represented in Fig. 147, which is drawn from a measured -outcrop above Chuquibambilla. - -It will be seen that we have here more than a mere crinkling, such as -the mica schists of the Cordillera Vilcapampa display. The diversified -sedimentary series is folded and faulted on a large scale with broad -structural undulations visible for miles along the abrupt valley walls. -Here and there, however, the strata become weaker generally through the -thinning of the beds and the more rapid alternation of hard and soft -layers, and for short distances they have absorbed notable amounts of -the stresses induced by the igneous intrusions. In such places not only -the structure but the composition of the rock shows the effects of the -intrusion. Certain shales in the section are carbonaceous and in all -observed cases the organic matter has been transformed to anthracite, a -condition generally associated with a certain amount of minute mashing -and a cementation of both limestone and sandstone. - -[Illustration: FIG. 147--Overthrust folds in detail on the southwestern -border of the Vilcapampa batholith near Chuquibambilla. The section is -fifteen feet high. Elevation, 13,100 feet (4,000 m.). For comparison -with the structural effects of the Vilcapampa intrusion on the northeast -see Fig. 142.] - -The granite becomes notably darker on approach to the northeastern -contact near Colpani; the proportion of ferro-magnesian minerals in some -cases is so large as to give a distinctly black color in sharp contrast -to the nearly white granite typical of the central portion of the mass. -Large masses of shale foundered in the invading magma, and upon fusion -gave rise to huge black masses impregnated with quartz and in places -smeared or injected with granite magma. Everywhere the granite is marked -by numbers of black masses which appear at first sight to be -aggregations of dark minerals normal to the granite and due to -differentiation processes at the time of crystallization. It is, -however, noteworthy that these increase rapidly in number on approach to -the contact, until in the last half-mile they appear to grade into the -shale inclusions. It may, therefore, be doubted that they are -aggregations. From their universal distribution, their uniform -character, and their marked increase in numbers on approach to lateral -contacts, it may reasonably be inferred that they represent foundered -masses of country rock. Those distant from present contacts are in -almost all cases from a few inches to a foot in diameter, while on -approach to lateral contacts they are in places ten to twenty feet in -width, as if the smaller areas represented the last remnants of large -inclusions engulfed in the magma near the upper or roof contact. They -are so thoroughly injected with silica and also with typical granite -magma as to make their reference to the country rock less secure on -petrographical than on purely distributional grounds. - -A parallel line of evidence relates to the distribution of complementary -dikes throughout the granite. In the main mass of the batholith the -dikes are rather evenly distributed as to kind with a slight -preponderance of the dark-colored group. Near the contact, however, -aplitic dikes cease altogether and great numbers of melanocratic dikes -appear. It may be inferred that we have in this pronounced condition -suggestions of strong influence upon the final processes of invasion and -cooling of the granite magma, on the part of the country rock detached -and absorbed by the invading mass. It might be supposed that the -indicated change in the character of the complementary dikes could be -ascribed to possible differentiation of the granite magma whereby a -darker facies would be developed toward the Colpani contact. It has, -however, been pointed out already that the darkening of the granite in -this direction is intimately related to a marked increase in the number -of inclusions, leaving little doubt that the thorough digestion of the -smaller masses of detached shales is responsible for the marked increase -in the number and variety of the ferro-magnesian and special contact -minerals. - -Upon the southwestern border of the batholith the number of aplitic -dikes greatly increases. They form prominent features, not only of the -granite, but also of the schists, adding greatly to the strong contrast -between the schist of the border zone and that outside the zone of -metamorphism. In places in the border schists, these are so numerous -that one may count up to twenty in a single view, and they range in size -from a few inches to ten or fifteen feet. The greater fissility of the -schists as contrasted with the shales on the opposite or eastern margin -of the batholith caused them to be relatively much more passive in -relation to the granite magma. They were not so much torn off and -incorporated in the magma, as they were thoroughly injected and -metamorphosed. Added to this is the fact that they are petrographically -more closely allied to the granite than are the shales upon the -northeastern contact. - - - - -CHAPTER XIV - -THE COASTAL TERRACES - - -Along the entire coast of Peru are upraised and dissected terraces of -marine origin. They extend from sea level to 1,500 feet above it, and -are best displayed north of Mollendo and in the desert south of Payta. -The following discussion relates to that portion of the coast between -Mollendo and Camaná. - -At the time of the development of the coastal terraces the land was in a -state of temporary equilibrium, for the terraces were cut to a mature -stage as indicated by the following facts: (1) the terraces have great -width--from one to five and more miles; (2) their inner border is -straight, or, where curves exist, they are broad and regular; (3) the -terrace tops are planed off smoothly so that they now have an even -gradient and an almost total absence of rock stacks or unreduced spurs; -(4) the mature slopes of the Coast Range, strikingly uniform in gradient -and stage of development (Fig. 148), are perfectly organized with -respect to the inner edge of the terrace. They descend gradually to the -terrace margin, showing that they were graded with respect to sea level -when the sea stood at the inner edge of the highest terrace. - -From the composition and even distribution of the thick-bedded Tertiary -deposits of the desert east of the Coast Range, it is concluded that the -precipitation of Tertiary time was greater than that of today (see p. -261). Therefore, if the present major streams reach the sea, it may also -be concluded that those of an earlier period reached the sea, provided -the topography indicates the perfect adjustment of streams to structure. -Lacustrine sediments are absent throughout the Tertiary section. Such -through-flowing streams, discharging on a stable coast, would also have -mature valleys as a consequence of long uninterrupted erosion at a fixed -level. The Majes river must have cut through the Coast Range at Camaná -then as now. Likewise the Vitor at Quilca must have cut straight across -the Coast Range. An examination of the surface leading down from the -Coast Range to the upper edge of these valleys fully confirms this -deduction. Flowing and well-graded slopes descend to the brink of the -inner valley in each case, where they give way to the gorge walls that -continue the descent to the valley floor. - -Confirmatory evidence is found in the wide Majes Valley at Cantas and -Aplao. (See the Aplao Quadrangle for details.) Though the observer is -first impressed with the depth of the valley, its width is more -impressive still. It is also clear that two periods of erosion are -represented on its walls. Above Aplao the valley walls swing off to the -west in a great embayment quite inexplicable on structural grounds; in -fact the floor of the embayment is developed across the structure, which -is here more disordered than usual. The same is true below Cantas, as -seen from the trail, which drops over two scarps to get to the valley -floor. The upper, widely opened valley is correlated with the latter -part of the period in which were formed the mature terraces of the coast -and the mature slopes bordering the larger valleys where they cross the -Coast Range. - -After its mature development the well-graded marine terrace was upraised -and dissected. The deepest and broadest incisions in it were made where -the largest streams crossed it. Shallower and narrower valleys were -formed where the smaller streams that headed in the Coast Range flowed -across it. Their depth and breadth was in general proportional to the -height of that part of the Coast Range in which their headwaters lay and -to the size of their catchment basins. - -When the dissection of the terrace had progressed to the point where -about one-third of it had been destroyed, there came depression and the -deposition of Pliocene or early Pleistocene sands, gravels, and local -clay beds. Everywhere the valleys were partly or wholly filled and over -broad stretches, as in the vicinity of stream mouths and upon lower -portions of the terrace, extensive deposits were laid down. The largest -deposits lie several hours' ride south of Camaná, where locally they -attain a thickness of several hundred feet. Their upper surface was well -graded and they show a prolonged period of deposition in which the -former coastal terrace was all but concealed. - -[Illustration: FIG. 148--The Coast Range between Mollendo and Arequipa -at the end of June, 1911. There is practically no grass and only a few -dry shrubs. The fine network over the hill slopes is composed of -interlacing cattle tracks. The cattle roam over these hills after the -rains which come at long intervals. (See page 141 for description of the -rains and the transformations they effect. For example, in October, -1911, these hills were covered with grass.)] - -[Illustration: FIG. 149--The great marine terrace at Mollendo. See Fig. -150 for profile.] - -The uplift of the coast terrace and its subsequent dissection bring the -physical history down to the present. The uplift was not uniform; three -notches in the terrace show more faintly upon the granite-gneiss where -the buried rock terrace has been swept clean again, more strongly upon -the softer superimposed sands. They lie below the 700-foot contour and -are insignificant in appearance beside the slopes of the Coast Range or -the ragged bluff of the present coast. - -The effect of the last uplift of the coast was to impel the Majes River -again to cut down its lower course nearly to sea level. The Pliocene -terrace deposits are here entirely removed over an area several leagues -wide. In their place an extensive delta and alluvial fan have been -formed. At first the river undoubtedly cut down to base level at its -mouth and deposited the cut material on the sea floor, now shoal, for a -considerable distance from shore. We should still find the river in that -position had other agents not intervened. But in the Pleistocene a great -quantity of waste was swept into the Majes Valley, whereupon aggradation -began; and in the middle and lower valley it has continued down to the -present. - -[Illustration: FIG. 150--Profile of the coastal terraces at Mollendo. At -1, in a tributary gorge, fossiliferous clay occurs at 800 feet elevation -above the sea. At 2 is a characteristic change of profile marking a drop -from a higher to a lower terrace. On the extreme left is the highest -terrace, just under 1,500 feet (460 m.).] - -[Illustration: FIGS. 151-154--These four diagrams represent the physical -history and the corresponding physiographic development of the coastal -region of Peru between Camaná and Mollendo. The sedimentary beds in the -background of the first diagram are hypothetical and are supposed to -correspond to the quartzites of the Majes Valley at Aplao.] - -The effect has been not only the general aggradation of the valley -floor, but also the development of a combined delta and superimposed -alluvial fan at the valley mouth. The seaward extension of the delta has -been hastened by the gradation of the shore between the bounding -headlands, thus giving rise to marine marshes in which every particle of -contributed waste is firmly held. The plain of Camaná, therefore, -includes parts of each of the following: a delta, a superposed alluvial -fan, a salt-water marsh, a fresh-water marsh, a series of beaches, small -amounts of piedmont fringe at the foot of Pliocene deposits once trimmed -by the river and by waves, and extensive tracts of indefinite fill. (See -the Camaná Quadrangle for details.) - -With the coastal conditions now before us it will be possible to attempt -a correlation between the erosion features and the deposits of the coast -and those of the interior. An understanding of the comparisons will be -facilitated by the use of diagrams, Figs. 151-154, and by a series of -concise summary statements. From the relations of the figure it appears -that: - -1. The Tertiary deposits bordering the Majes Valley east of the Coast -Range were in process of deposition when the sea planed the coastal -terrace (Fig. 151). - -2. A broad mature marine terrace without stacks or sharply alternating -spurs and reëntrants (though the rock is a very resistant granite) is -correlated with the mature grades of the Coast Range, with which they -are integrated and with the mature profiles of the main Cordillera. - -3. Such a high degree of topographic organization requires the -dissection in the _late_ stages of the erosion cycle of at least the -inner or eastern border of the piedmont deposits of the desert, largely -accumulated during the _early_ stages of the cycle. - -4. Since the graded slopes of the Coast Range on the one side descend to -a former shore whose elevation is now but 1,500 feet above sea level, -and since only ten to twenty miles inland on the other side of the -range, the same kind of slope extends beneath Tertiary deposits 4,000 -feet above sea level, it appears that aggradation of the outer (or -western) part of the Tertiary deposits on the eastern border of the -Coast Range continued down to the end of the cycle of erosion, though - -5. There must have been an outlet to the sea, since, as we have already -seen, the water supply of the Tertiary was greater than that of today -and the present streams reach the sea. Moreover, the mature upper slopes -and the steep lower slopes of the large valleys make a pronounced -topographic unconformity, showing two cycles of valley development. - -6. Upon uplift of the coast and dissection of the marine terraces at the -foot of the Coast Range, the streams cut deep trenches on the floors of -their former valleys (Fig. 152) and removed (a) large portions of the -coast terrace, and (b) large portions of the Tertiary deposits east of -the Coast Range. - -7. Depression of the coastal terrace and its partial burial meant the -drowning of the lower Majes Valley and its partial filling with marine -and later with terrestrial deposits. It also brought about the partial -filling by stream aggradation of the middle portion of the valley, -causing the valley fill to abut sharply against the steep valley walls. -(See Fig. 155.) - -8. Uplift and dissection of both the terrace and its overlying sediments -would be accompanied by dissection of the former valley fill, provided -that the waste supply was not increased and that the uplift was regional -and approximately equal throughout--not a bowing up of the coast on the -one hand, or an excessive bowing up of the mountains on the other. But -the waste supply has not remained constant, and the uplift has been -greater in the Cordillera than on the coast. Let us proceed to the proof -of these two conclusions, since upon them depends the interpretation of -the later physical history of the coastal valleys. - -[Illustration: FIG. 155--Steep walls in the Majes Valley below Cantas -and the abrupt termination against them of a deep alluvial fill.] - -[Illustration: FIG. 156--Canyon of the Majes River through the Coast -Range north of Camaná. The rock is a granite-gneiss capped by rather -flat-lying sedimentaries.] - -It is known that the Pleistocene was a time of augmented waste delivery. -At the head of the broadly opened Majes Valley there was deposited a -huge mass of extremely coarse waste several hundred feet deep and -several miles long. Forward from it, interstratified with its outer -margin, and continuing the same alluvial grade, is a still greater mass -of finer material which descends to lower levels. The fine material is -deposited on the floor of a valley cut into Tertiary strata, hence it -is younger than the Tertiary. It is now, and has been for some time -past, in process of dissection, hence it was not formed under present -conditions of climate and relief. It is confidently assigned to the -Pleistocene, since this is definitely known to have been a time of -greater precipitation and waste removal on the mountains, and deposition -on the plains and the floors of mountain valleys. Such a conclusion -appears, even on general grounds, to be but a shade less reliable than -if we were able to find in the upper Majes Valley, as in so many other -Andean valleys, similar alluvial deposits interlocked with glacial -moraines and valley trains. - -In regard to the second consideration--the upbowing of the -Cordillera--it may be noted that the valley and slope profiles of the -main Cordillera shown on p. 191, when extended toward the margin of the -mountain belt, lie nearly a mile above the level of the sea on the west -and the Amazon plains on the east. The evidence of regional bowing thus -afforded is checked by the depths of the mountain valleys and the stream -profiles in them. The streams are now sunk from one to three thousand -feet below their former level. Even in the case of three thousand feet -of erosion the stream profiles are still ungraded, the streams -themselves are almost torrential, and from one thousand to three -thousand feet of vertical cutting must still be accomplished before the -profiles will be as gentle and regular as those of the preceding cycle -of erosion, in which were formed the mature slopes now lying high above -the valley floors. - -Further evidence of bowing is afforded by the attitude of the Tertiary -strata themselves, more highly inclined in the case of the older -Tertiary, less highly inclined in the case of the younger Tertiary. It -is noteworthy that the gradient of the present valley floor is -distinctly less than that of the least highly inclined strata. This is -true even where aggradation is now just able to continue, as near the -nodal point of the valley, above Aplao, where cutting ceases and -aggradation begins. (See the Aplao Quadrangle for change of function on -the part of the stream a half mile above Cosos). Such a progressive -steepening of gradients in the direction of the oldest deposits, shows -very clearly a corresponding progression in the growth of the Andes at -intervals throughout the Tertiary. - -Thus we have aggradation in the Tertiary at the foot of the growing -Andes; aggradation in the Pliocene or early Pleistocene on the floor of -a deep valley cut in earlier deposits; aggradation in the glacial epoch; -and aggradation now in progress. Basin deposits within the borders of -the Peruvian Andes are relatively rare. The profound erosion implied by -the development, first of a mature topography across this great -Cordillera, and second of many deep canyons, calls for deposition on an -equally great scale on the mountain borders. The deposits of the western -border are a mile thick, but they are confined to a narrow zone between -the Coast Range and the Cordillera. Whatever material is swept beyond -the immediate coast is deposited in deep ocean water, for the bottom -falls off rapidly. The deposits of the eastern border of the Andes are -carried far out over the Amazon lowland. Those of earlier geologic -periods were largely confined to the mountain border, where they are now -upturned to form the front range of the Andes. The Tertiary deposits of -the eastern border are less restricted, though they appear to have -gathered chiefly in a belt from fifty to one hundred miles wide. - -The deposits of the western border were laid down by short streams -rising on a divide only 100 to 200 miles from the Pacific. Furthermore, -they drain the dry leeward slopes of the Andes. The deposits of the wet -eastern border were made by far larger streams that carry the waste of -nearly the whole Cordillera. Their shoaling effect upon the Amazon -depression must have been a large factor in its steady growth from an -inland sea to a river lowland. - - - - -CHAPTER XV - -PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT - -GENERAL FEATURES - - -In the preceding chapter we employed geologic facts in the determination -of the age of the principal topographic forms. These facts require -further discussion in connection with their closest physiographic allies -if we wish to show how the topography of today originated. There are -many topographic details that have a fundamental relation to structure; -indeed, without a somewhat detailed knowledge of geology only the -broader and more general features of the landscape can be interpreted. -In this chapter we shall therefore refer not to the scenic features as -in a purely topographic description, but to the rock structure and the -fossils. A complete and technical geologic discussion is not desirable, -first, because it should be based upon much more detailed geologic field -work, and second because after all our main purpose is not to discuss -the geologic features _per se_, but the physiographic background which -the geologic facts afford. I make this preliminary observation partly to -indicate the point of view and partly to emphasize the necessity, in a -broad, geographic study, for the reconstruction of the landscapes of the -past. - -The two dominating ranges of the Peruvian Andes, called the Maritime -Cordillera and the Cordillera Vilcapampa, are composed of igneous -rock--the one volcanic lava, the other intrusive granite. The chief rock -belts of the Andes of southern Peru are shown in Fig. 157. The Maritime -Cordillera is bordered on the west by Tertiary strata that rest -unconformably upon Palaeozoic quartzites. It is bordered on the east by -Cretaceous limestones that grade downward into sandstones, shales, and -basal conglomerates. At some places the Cretaceous deposits rest upon -old schists, at others upon Carboniferous limestones and related -strata, upon small granite intrusives and upon old and greatly altered -volcanic rock. - -The Cordillera Vilcapampa has an axis of granitic rock which was thrust -upward through schists that now border it on the west and slates that -now border it on the east. The slate series forms a broad belt which -terminates near the eastern border of the Andes, where the mountains -break down abruptly to the river plains of the Amazon Basin. The -immediate border on the east is formed of vertical Carboniferous -limestones. The narrow foothill belt is composed of Tertiary sandstones -that grade into loose sands and conglomerates. The inclined Tertiary -strata were leveled by erosion and in part overlain by coarse and now -dissected river gravels, probably of Pleistocene age. Well east of the -main border are low ranges that have never been described. They could -not be reached by the present expedition on account of lack of time. On -the extreme western border of that portion of the Peruvian Andes herein -described, there is a second distinct border chain, the Coast Range. It -is composed of granite and once had considerable relief, but erosion has -reduced its former bold forms to gentle slopes and graded profiles. - -The continued and extreme growth of the Andes in later geologic periods -has greatly favored structural and physiographic studies. Successive -uplifts have raised earlier deposits once buried on the mountain flanks -and erosion has opened canyons on whose walls and floors are the clearly -exposed records of the past. In addition there have been igneous -intrusions of great extent that have thrust aside and upturned the -invaded strata exposing still further the internal structures of the -mountains. From sections thus revealed it is possible to outline the -chief events in the history of the Peruvian Andes, though the outline is -still necessarily broad and general because based on rapid -reconnaissance. However, it shows clearly that the landscape of the -present represents but a temporary stage in the evolution of a great -mountain belt. At the dawn of geologic history there were chains of -mountains where the Andes now stand. They were swept away and even their -roots deeply submerged under invading seas. Repeated uplifts of the -earth's crust reformed the ancient chains or created new ones out of the -rock waste derived from them. Each new set of forms, therefore, exhibits -some features transmitted from the past. Indeed, the landscape of today -is like the human race--inheriting much of its character from past -generations. For this reason the philosophical study of topographic -forms requires at least a broad knowledge of related geologic -structures. - -[Illustration: FIG. 157--Outline sketch showing the principal rock belts -of Peru along the seventy-third meridian. They are: _1_, Pleistocene and -Recent gravels and sands, the former partly indurated and slightly -deformed, with the degree of deformation increasing toward the mountain -border (south). _2_, Tertiary sandstones, inclined from 15° to 30° -toward the north and unconformably overlain by Pleistocene gravels. _3_, -fossil-bearing Carboniferous limestones with vertical dip. _4_, -non-fossiliferous slates, shales, and slaty schists (Silurian) with -great variation in degree of induration and in type of structure. South -of the parallel of 13° is a belt of Carboniferous limestones and -sandstones bordering (_5_), the granite axis of the Cordillera -Vilcapampa. For its structural relations to the Cordillera see Figs. 141 -and 142. _6_, old and greatly disturbed volcanic agglomerates, tuffs and -porphyries, and quartzitic schists and granite-gneiss. _7_, principally -Carboniferous limestones north of the axis of the Central Ranges and -Cretaceous limestones south of it. Local granite batholiths in the axis -of the Central Ranges. _8_, quartzites and slates predominating with -thin limestones locally. South of 8 is a belt of shale, sandstone, and -limestone with a basement quartzite appearing on the valley floors. _9_, -a portion of the great volcanic field of the Central Andes and -characteristically developed in the Western or Maritime Cordillera, -throughout northern Chile, western Bolivia, and Peru. At Cotahuasi (see -also Fig. 20) Cretaceous limestones appear beneath the lavas. _10_, -Tertiary sandstones of the coastal desert with a basement of old -volcanics and quartzites appearing on the valley walls. The valley floor -is aggraded with Pleistocene and Recent alluvium. _11_, granite-gneiss -of the Coast Range. _12_, late Tertiary or Pleistocene sands and gravels -deposited on broad coastal terraces. For rock structure and character -see the other figures in this chapter. For a brief designation of index -fossils and related forms see Appendix B. For the names of the drainage -lines and the locations of the principal towns see Figs. 20 and 204.] - - -SCHISTS AND SILURIAN SLATES[50] - -The oldest series of rocks along the seventy-third meridian of Peru -extends eastward from the Vilcapampa batholith nearly to the border of -the Cordillera, Fig. 157. It consists of (1) a great mass of slates and -shales with remarkable uniformity of composition and structure over -great areas, and (2) older schists and siliceous members in restricted -belts. They are everywhere thoroughly jointed; near the batholith they -are also mineralized and altered from their original condition; in a few -places they have been intruded with dikes and other form of igneous -rock. - -The slates and shales underlie known Carboniferous strata on their -eastern border and appear to be a physical continuation of the -fossiliferous slates of Bolivia; hence they are provisionally referred -to the Silurian, though they may possibly be Devonian. Certainly the -known Devonian exceeds in extent the known Silurian in the Central Andes -but its lithological character is generally quite unlike the character -of the slates here referred to the Silurian. The schists are of great -but unknown age. They are unconformably overlain by known Carboniferous -at Puquiura in the Vilcapampa Valley (Fig. 158), and near Chuquibambilla -on the opposite side of the Cordillera Vilcapampa. The deeply weathered -fissile mica schists east of Pasaje (see Appendix C for all locations) -are also unconformably overlain by conglomerate and sandstone of -Carboniferous age. While the schists vary considerably in lithological -appearance and also in structure, they are everywhere the lowest rocks -in the series and may with confidence be referred to the early -Palaeozoic, while some of them may date from the Proteriozoic. - -[Illustration: FIG. 158--Geologic sketch map of the lower Urubamba -Valley. A single traverse was made along the valley, hence the -boundaries are not accurate in detail. They were sketched in along a few -lateral traverses and also inferred from the topography. The country -rock is schist and the granite intruded in it is an arm of the main -granite mass that constitutes the axis of the Cordillera Vilcapampa. The -structure and to some degree the extent of the sandstone on the left are -represented in Figs. 141 and 142.] - -The Silurian beds are composed of shale, sandstone, shaly sandstone, -limestone, and slate with some slaty schist, among which the shales are -predominent and the limestones least important. Near their contact with -the granite the slate series is composed of alternating beds of -sandstone and shale arranged in beds from one to three feet thick. At -Santa Ana they become more fissile and slaty in character and in several -places are quarried and used for roofing. At Rosalina they consist of -almost uniform beds of shale so soft and so minutely and thoroughly -jointed as to weather easily. Under prolonged erosion they have, -therefore, given rise to a well-rounded and soft-featured landscape. -Farther down the Urubamba Valley they again take on the character of -alternating beds of sandstone and shale from a few feet to fifteen and -more feet thick. In places the metamorphism of the series has been -carried further--the shales have become slates and the sandstones have -been altered to extremely resistant quartzites. The result is again -clearly shown in the topography of the valley wall which becomes bold, -inclosing the river in narrow "pongos" or canyons filled with huge -bowlders and dangerous rapids. The hills become mountains, ledges -appear, and even the heavy forest cover fails to smooth out the natural -ruggedness of the landscape. - -It is only upon their eastern border that the Silurian series includes -calcareous beds, and all of these lie within a few thousand yards of the -contact with the Carboniferous limestones and shales. At first they are -thin paper-like layers; nearer the top they are a few inches wide and -finally attain a thickness of ten or twelve feet. The available -limestone outcrops were rigorously examined for fossils but none were -found, although they are lavishly distributed throughout the younger -Carboniferous beds just above them. It is also remarkable that though -the Silurian age of these beds is reasonably inferred they are not -separated from the Carboniferous by an unconformity, at least we could -find none in this locality. The later beds disconformably overlie the -earlier beds, although the sharp differences in lithology and fossils -make it easy to locate the line of separation. The limestone beds of the -Silurian series are extremely compact and unfossiliferous. At least in -this region those of Carboniferous age are friable and the fossils -varied and abundant. The Silurian beds are everywhere strongly inclined -and throughout the eastern half or third of their outcrop in the -Urubamba Valley they are nearly vertical. - -In view of the enormous thickness of the repeated layers of shale and -sandstone this series is of great interest. Added importance attaches to -their occurrence in a long belt from the eastern edge of the Bolivian -highlands northward through Peru and possibly farther. From the fact -that their disturbance has been on broad lines over wide areas with -extreme metamorphism, they are to be separated from the older -mica-schists and the crumpled chlorite schists of Puquiura and Pasaje. -Further reasons for this distinction lie in their lithologic difference -and, to a more important degree, in the strong unconformity between the -Carboniferous and the schists in contrast to the disconformable -relations shown between the Carboniferous and Silurian fifty miles away -at Pongo de Mainique. The mashing and crumpling that the schists have -experienced at Puquiura is so intense, that were they a part of the -Silurian series the latter should exhibit at least a slight unconformity -in relation to the Carboniferous limestones deposited upon them. - -If our interpretation of the relation of the schists to the slates and -shales be correct, we should have a mountain-making period introduced in -pre-Silurian time, affecting the accumulated sediments and bringing -about their metamorphism and crumpling on a large scale. From the -mountains and uplands thus created on the schists, sediments were washed -into adjacent waters and accumulated as even-bedded and extensive sheets -of sands and muds (the present slates, shales, quartzites, etc.). -Nowhere do the sediments of the slate series show a conglomeratic phase; -they are remarkably well-sorted and consist of material disposed with -great regularity. Though they are coarsest at the bottom the lower beds -do not show cross-bedding, ripple marking, or other signs of -shallow-water conditions. Toward the upper part of the series these -features, especially the ripple-marking, make their appearance. During -the deposition of the last third of the series, and again just before -the deposition of the limestone, the beds took on a predominantly -arenaceous character associated with ripple marks and cross-bedding -characteristic of shallow-water deposits. - -In the persistence of arenaceous sediments throughout the series and the -distribution of the ripple marks through the upper third of the beds, we -have a clear indication that the degree of shallowness was sufficient to -bring the bottom on which the sediments accumulated into the zone of -current action and possibly wave action. It is also worth considering -whether the currents involved were not of similar origin to those now a -part of the great counter-clockwise movements in the southern seas. If -so, their action would be peculiarly effective in the wide distribution -of the sediment derived from a land mass on the eastern edge of a -continental coast, since they would spread out the material to a greater -and greater degree as they flowed into more southerly latitudes. Among -geologic agents a broad ocean current of relatively uniform flow would -produce the most uniform effects throughout a geologic period, in which -many thousand feet of clastic sediments were being accumulated. A -powerful ocean current would also work on flats (in contrast to the -gradient required by near-shore processes), and at the same time be of -such deep and steady flow as to result in neither ripple marks nor -cross-bedding. - -The increasing volume of shallow-water sediments of uniform character -near the end of the Silurian, indicates great crustal stability at a -level which brought about neither a marked gain nor loss of material to -the region. At any rate we have here no Devonian sediments, a -characteristic shared by almost all the great sedimentary formations of -Peru. At the beginning of the Carboniferous the water deepened, and -great heavy-bedded limestones appear with only thin shale partings -through a vertical distance of several hundreds of feet. The enormous -volume of Silurian sediments indicates the deep and prolonged erosion of -the land masses then existing, a conclusion further supported (1) by the -extensive development of the Silurian throughout Bolivia as well as -Peru, (2) by the entire absence of coarse material whether at the top or -bottom of the section, and (3) by the very limited extent of older rock -now exposed even after repeated and irregular uplift and deep -dissection. Indeed, from the latter very striking fact, it may be -reasonably argued that in a general way the relief of the country was -reduced to sea level at the close of the Silurian. Over the perfected -grades of that time there would then be afforded an opportunity for the -effective transportation of waste to the extreme limits of the land. - -Further evidence of the great reduction of surface during the Silurian -and Devonian is supplied by the extensive development of the -Carboniferous strata. Their outcrops are now scattered across the higher -portions of the Andean Cordillera and are prevailingly calcareous in -their upper portions. Upon the eastern border of the Silurian they -indicate marine conditions from the opening of the period, but at Pasaje -in the Apurimac Valley they are marked by heavy beds of basal -conglomerate and sandstone, and an abundance of ripple marking and other -features associated with shallow-water and possibly near-shore -conditions. - - -CARBONIFEROUS - -Carboniferous strata are distributed along the seventy-third meridian -and rival in extent the volcanic material that forms the western border -of the Andes. They range in character from basal conglomerates, -sandstones, and shales of limited development, to enormous beds of -extremely resistant blue limestone, in general well supplied with -fossils. On the eastern border of the Andes they are abruptly terminated -by a great fault, the continuation northward of the marginal fault -recognized in eastern Bolivia by Minchin[51] and farther north by the -writer.[52] Coarse red sandstones with conglomeratic phase abut sharply -and with moderate inclination against almost vertical sandstones and -limestones of Carboniferous age. The break between the vertical -limestones and the gently inclined sandstones is marked by a prominent -scarp nearly four thousand feet high (Fig. 159), and the limestone -itself forms a high ridge through which the Urubamba has cut a narrow -gateway, the celebrated Pongo de Mainique. - -[Illustration: FIG. 159--Topographic and structural section at the -northeastern border of the Peruvian Andes. The slates are probably -Silurian, the fossiliferous limestones are known Carboniferous, and the -sandstones are Tertiary grading up to Pleistocene.] - -At Pasaje, on the western side of the Apurimac, the Carboniferous again -appears resting upon the old schists described on p. 236. It is steeply -upturned, in places vertical, is highly conglomeratic, and in a belt a -half-mile wide it forms true badlands topography. It is succeeded by -evenly bedded sandstones of fine and coarse composition in alternate -beds, then follow shales and sandstones and finally the enormous beds of -limestone that characterize the series. The structure is on the whole -relatively simple in this region, the character and attitude of the beds -indicating their accumulation in a nearly horizontal position. Since the -basal conglomerate contains only pebbles and stones derived from the -subjacent schists and does not contain granites like those in the -Cordillera Vilcapampa batholith on the east it is concluded that the -batholithic invasion was accompanied by the compression and tilting of -the Carboniferous beds and that the batholith itself is -post-Carboniferous. From the ridge summits above Huascatay and in the -deep valleys thereabouts the Carboniferous strata may be seen to extend -far toward the west, and also to have great extent north and south. -Because of their dissected, bare, and, therefore, well-exposed condition -they present exceptional opportunities for the study of Carboniferous -geology in central Peru. - -[Illustration: FIG. 160--The deformative effects of the granite -intrusion of the Cordillera Vilcapampa are here shown as transmitted -through ancient schists to the overlying conglomerates, sandstones, and -limestones of Carboniferous age, in the Apurimac Valley at Pasaje.] - -Carboniferous strata again appear at Puquiura, Vilcapampa, and -Pampaconas. They are sharply upturned against the Vilcapampa batholith -and associated volcanic material, chiefly basalt, porphyry, and various -tuffs and related breccias. The Carboniferous beds are here more -arenaceous, consisting chiefly of alternating beds of sandstone and -shale. The lowermost beds, as at Pongo de Mainique, are dominantly -marine, fossiliferous limestone beds having a thickness estimated to be -over two miles. - -From Huascatay westward and southward the Carboniferous is in part -displaced by secondary batholiths of granite, in part cut off or crowded -aside by igneous intrusions of later date, and in still larger part -buried under great masses of Tertiary volcanic material. Nevertheless, -it remains the dominating rock type over the whole stretch of country -from Huascatay to Huancarama. In the northwestern part of the Abancay -sheet its effect on the landscape may be observed in the knife-like -ridge extending from west to east just above Huambo. Above -Chuquibambilla it again outcrops, resting upon a thick resistant -quartzite of unknown age, Fig. 162. It is strongly developed about -Huadquirca and Antabamba and, still associated with a quartzite floor, -it finally disappears under the lavas of the great volcanic field on the -western border of the Andes. Figs. 141 and 142 show its relation to the -invading granite batholiths and Fig. 162 shows further structural -features as developed about Antabamba where the great volcanic field of -the Maritime Cordillera begins. - -[Illustration: FIG. 161--Types of deformation north of Lambrama near -Sotospampa. A dark basaltic rock has invaded both granite-gneiss and -slate. Sills and dikes occur in great numbers. The topographic -depression in the profile is the Lambrama Valley. See the Lambrama -Quadrangle.] - -Both the enormous thickness of the Carboniferous limestone series and -the absence of clastic members over great areas in the upper portion of -the series prove the widespread extent of the Carboniferous seas and -their former occurrence in large interlimestone tracts from which they -have since been eroded. At Puquiura they extend far over the schist, in -fact almost completely conceal it; at Pasaje they formerly covered the -mica-schists extensively, their erosion in both cases being conditioned -by the pronounced uplift and marginal deformation which accompanied the -development of the Vilcapampa batholith. - -[Illustration: FIG. 162--Sketch sections at Antabamba to show (a) -deformed limestones on the upper edge of the geologic map, Fig. 163 A; -and (b) the structural relations of limestone and quartzite. See also -Fig. 163.] - -The degree of deformation of the Carboniferous sediments varies between -simple uplift through moderate folding and complex disturbances -resulting in nearly vertical attitudes. The simplest structures are -represented at Pasaje, where the uplift of the intruded schists, -marginal to the Vilcapampa batholith, has produced an enormous -monoclinal fold exposing the entire section from basal conglomerates and -sandstones to the thickest limestone. Above Chuquibambilla the -limestones have been uplifted and very gently folded by the invasion of -granite associated with the main batholith and several satellitic -batholiths of limited extent. A higher degree of complexity is shown at -Pampaconas (Fig. 141), where the main monoclinal fold is traversed -almost at right angles by secondary folds of great amplitude. The -limestones are there carried to the limit of the winter snows almost at -the summit of the Cordillera. The crest of each secondary anticline -rises to form a group of conspicuous peaks and tabular ridges. Higher in -the section, as at Puquiura, the sandstones are thrown into a series of -huge anticlines and synclines, apparently by the marginal compression -brought about at the time of the intrusion of the granite core of the -range. At Pongo de Mainique the whole of the visible Carboniferous is -practically vertical, and is cut off by a great fault marking the abrupt -eastern border of the Cordillera. - -[Illustration: FIG. 163--Geologic sketch section to show the relation of -the volcanic flows of Fig. 164 to the sandstones and quartzites -beneath.] - -It is noteworthy that the farther east the Carboniferous extends the -more dominantly marine it becomes, though marine beds of great thickness -constitute a large part of the series in whatever location. From -Huascatay westward the limestones become more and more argillaceous, and -finally give way altogether to an enormous thickness of shales, -sandstones, and thin conglomerates. These were observed to extend with -strong inclination westward out of the region studied and into and under -the volcanoes crowning the western border of the Cordillera. Along the -line of traverse opportunity was not afforded for further study of this -aspect of the series, since our route led generally along the strike -rather than along the dip of the beds. It is interesting to note, -however, that these observations as to the increasing amounts of clastic -material in a westward direction were afterwards confirmed by Señor José -Bravo, the Director of the Bureau of Mines at Lima, who had found -Carboniferous land plants in shales at Pacasmayo, the only fossils of -their kind found in Peru. Formerly it had been supposed that non-marine -Carboniferous was not represented in Peru. From the varied nature of the -flora, the great thickness of the shales in which the specimens were -collected, and the fact that the dominantly marine Carboniferous -elsewhere in Peru is of great extent, it is concluded that the land upon -which the plants grew had a considerable area and probably extended far -west of the present coast line. Since its emergence it has passed -through several orogenic movements. These have resulted in the uplift of -the marine portion of the Carboniferous, while the terrestrial deposits -seem to have all but disappeared in the down-sunken blocks of the ocean -floor, west of the great fault developed along the margin of the -Cordillera. The following figures are graphic representations of this -hypothesis. - -[Illustration: FIG. 164--Geologic sketch map and section, Antabamba -region. The Antabamba River has cut through almost the entire series of -bedded strata]. - -[Illustration: FIG. 165--The upper diagram (A) represents the -hypothetical distribution of land and sea during the Carboniferous -Period, as inferred from the present distribution and character of -Carboniferous limestones and slates. The lower diagram (B) represents -the present relief. The dotted line at the left of the two diagrams -connects identical points. The fragmentation of the former continental -border is believed to have left only a small portion of a former coastal -chain and to have been contemporaneous with the development of ocean -abysses near the present shore.] - -The wide distribution of the Carboniferous sediments and especially the -limestones, together with the uniformity of the fossil faunas, makes it -certain that the sea extended entirely across the region now occupied -by the Andes. However, from the relation of the Carboniferous to the -basal schists, and the most conservative extension of the known -Carboniferous, it may be inferred that the Carboniferous sea did not -completely cover the entire area but was broken here and there by island -masses in the form of an elongated archipelago. The presence of land -plants in the Carboniferous of Pisco warrants the conclusion that a -second island mass, possibly an island chain parallel to the first, -extended along and west of the present shore. - - -CRETACEOUS - -The Cretaceous formations are of very limited extent in the belt of -country under consideration, in spite of their generally wide -distribution in Peru. They are exposed distinctly only on the western -border of the Cordillera and in special relations. In the gorge of -Cotahuasi, over seven thousand feet deep, about two thousand feet of -Cretaceous limestones are exposed. The series includes only a very -resistant blue limestone and terminates abruptly along a well-marked and -highly irregular erosion surface covered by almost a mile of volcanic -material, chiefly lava flows. The character of the bottom of the section -is likewise unknown, since it lies apparently far below the present -level of erosion. - -[Illustration: FIG. 166--Geologic sketch map and cross-section in the -Cotahuasi Canyon at Cotahuasi. With a slight gap this figure continues -Fig. 167 to the left. The section represents a spur of the main plateau -about 1,500 feet high in the center of the map.] - -The Cretaceous limestones of the Cotahuasi Canyon are everywhere greatly -and irregularly disturbed. Typical conditions are represented in the -maps and sections, Figs. 166 and 167. They are penetrated and tilted by -igneous masses, apparently the feeders of the great lava sheets that -form the western summit of the Cordillera. From the restricted -development of the limestones along a western border zone it might be -inferred that they represent a very limited marine invasion. It is -certainly clear that great deformative movements were in progress from -at least late Palæozoic time since all the Palæozoic deposits are broken -abruptly down in this direction, and, except for such isolated -occurrences as the land Carboniferous at Pacasmayo, are not found -anywhere in the coastal region today. The Cretaceous is not only limited -within a relatively narrow shore zone, but also, like the Palæozoic, it -is broken down toward the west, not reappearing from beneath the -Tertiary cover of the desert region or upon the granite-gneisses that -form the foundation for all the known sedimentary strata of the -immediate coast. - -[Illustration: FIG. 167--Geologic sketch map and cross-section in the -Cotahuasi Canyon at Taurisma, above Cotahuasi. The relations of -limestone and lava flows in the center of the map and on a spur top near -the canyon floor. Thousands of feet of lava extend upward from the flows -that cap the limestone.] - -From these considerations I think we have a strong suggestion of the -geologic date assignable to the development of the great fault that is -the most strongly marked structural and physiographic feature of the -west coast of South America. Since the development of this fault is so -intimately related to the origin of the Pacific Ocean basin its study is -of special importance. The points of chief interest may be summarized as -follows: - -(1) The character of the land Carboniferous implies a much greater -extent of the land than is now visible. - -(2) The progressive coarsening of the Carboniferous deposits westward -and their land derivation, together with the great thickness of the -series, point to an elevated land mass in process of erosion west of -the series as a whole, that is west of the present coast. - -(3) The restricted development of the Cretaceous seas upon the western -border of the Carboniferous, and the still more restricted development -of the Tertiary deposits between the mountains and the present coast, -point to increasing definition of the submarine scarp through the -Mesozoic and the Tertiary. - -(4) The Tertiary deposits are all clearly derived from the present -mountains and have been washed seaward down slopes with geographic -relations approximately like those of the present. - -(5) From the great width, deep dissection, and subsequent burial of the -Tertiary terraces of the coast, it is clear that the greater part of the -adjustment of the crust to which the bordering ocean basin is due was -accomplished at least by mid-Tertiary time. - -[Illustration: FIG. 168--Composite structure section representing the -succession of rocks in the Urubamba Valley from Urubamba to Torontoy.] - -Aside from the fossiliferous limestones of known Cretaceous age there -have been referred to the Cretaceous certain red sandstones and shales -marked, especially in the central portions of the Cordillera, by the -presence of large amounts of salt and gypsum. These beds were at first -considered Permian, but Steinmann has since found at Potosí related and -similar formations with Cretaceous fossils. In this connection it is -also necessary to add that the great red sandstone series forming the -eastern border of the Andes in Bolivia is of uncertain age and has -likewise been referred to the Cretaceous, though the matter of its age -has not yet been definitely determined. In 1913 I found it appearing in -northwestern Argentina in the Calchaquí Valley in a relation to the main -Andean mass, similar to that displayed farther north. It contains -fossils and its age was, therefore, readily determinable there.[53] - -In the Peruvian field the red beds of questionable age were not examined -in sufficient detail to make possible a definite age determination. They -occur in a great and only moderately disturbed series in the Anta basin -north of Cuzco, but are there not fossiliferous. The northeastern side -of the hill back of Puqura (of the Anta basin: to be distinguished from -Puquiura in the Vilcabamba Valley) is composed largely of rocks of this -class. In a few places their calcareous members have been weathered out -in such a manner as to show karst topography. Where they occur on the -well-drained brow of a bluff the caves are used in place of houses by -Indian farmers. The large and strikingly beautiful Lake Huaipo, ten -miles north of Anta, and several smaller, neighboring lakes, appear to -have originated in solution depressions formed in these beds. - -[Illustration: FIG. 169--The line of unconformity between the igneous -basement rocks (agglomerates at this point) and the quartzites and -sandstones of the Urubamba Valley, between the town of Urubamba and -Ollantaytambo.] - -[Illustration: FIG. 170--The inclined lower and horizontal upper -sandstone on the southeastern wall of the Majes Valley at Hacienda -Cantas. The section is a half-mile high.] - -The structural relation of the red sandstone series to the older rocks -is well displayed about half-way between Urubamba and Ollantaytambo in -the deep Urubamba Valley. The basal rocks are slaty schist and granite -succeeded by agglomerates and basalt porphyries upon whose eroded -surfaces (Fig. 169) are gray to yellow cross-bedded sandstones. Within a -few hundred feet of the unconformity gypsum deposits begin to appear and -increase in number to such an extent that the resulting soil is in -places rendered worthless. Copper-stained bands are also common near the -bottom of the series, but these are confined to the lower beds. Higher -up in the section, for example, just above the gorge between Urubamba -and Ollantaytambo, even-bedded sandstones occur whose most prominent -characteristic is the regular succession of coarse and fine sandstone -beds. Such alternations of character in sedimentary rocks are commonly -marked by alternating shales and sandstones, but in this locality shales -are practically absent. Toward the top of the section gypsum deposits -again appear first as beds and later, as in the case of the hill-slope -on the southern shore of Lake Huaipo, as veins and irregular masses of -gypsum. The top of the deformed Cretaceous (?) is eroded and again -covered unconformably by practically flat-lying Tertiary deposits. - - -TERTIARY - -The Tertiary deposits of the region under discussion are limited to -three regions: (1) the extreme eastern border of the main Cordillera, -(2) intermontane basins, the largest and most important of which are (a) -the Cuzco basin and (b) the Titicaca-Poopó basin on the -Peruvian-Bolivian frontier, and (3) in the west-coast desert and in -places upon the huge terraces that form a striking feature of the -topography of the coast of Peru. - -It has already been pointed out that the eastern border of the -Cordillera is marked by a fault of great but undetermined throw, whose -topographic importance may be estimated from the fact that even after -prolonged erosion it stands nearly four thousand feet high. Cross-bedded -and ripple-marked features and small lenses of conglomerate are common. -The beds now dip at an angle approximately 20° to 50° northward at the -base of the scarp, but have decreasing dip as they extend farther north -and east. It is noteworthy that the deposits become distinctly -conglomeratic as flatter dips are attained, and that there seems to have -been a steady accumulation of detrital material from the mountains for a -long period, since the deposits pass in unbroken succession from the -highly indurated and massive beds of the mountain base to loose -conglomerates that now weather down much like an ordinary gravel bank. -In a few places just below the mouth of the Ticumpinea, logs about six -inches in diameter were observed embeded in the deposits, but these -belong distinctly to the upper horizons. - -The border deposits, though they vary in dip from nearly flat to 50°, -are everywhere somewhat inclined and now lie up to several hundred feet -above the level of the Urubamba River. Their upper surface is moderately -dissected, the degree of dissection being most pronounced where the dips -are steepest and the height greatest. In fact, the attitude of the -deposits and their progressive change in character point toward, if they -do not actually prove, the steady and progressive character of the beds -first deposited and their erosion and redeposition in beds now higher in -the series. - -Upon the eroded upper surfaces of the inclined border deposits, gravel -beds have been laid which, from evidence discussed in a later paragraph, -are without doubt referable to the Pleistocene. These in turn are now -dissected. They do not extend to the highest summits of the deformed -beds but are confined, so far as observations have gone, to elevations -about one hundred feet above the river. From the evidence that the -overlying horizontal beds are Pleistocene, the thick, inclined beds are -referred to Tertiary age, though they are nowhere fossiliferous. - -Observations along the Urubamba River were extended as far northward as -the mouth of the Timpia, one of the larger tributaries. Upon returning -from this point by land a wide view of the country was gained from the -four-thousand-foot ridge of vertical Carboniferous limestone, in which -it appeared that low and irregular strike ridges continue the features -of the Tertiary displayed along the mountain front far northward as well -as eastward, to a point where the higher ridges and low mountains of -older rock again appear--the last outliers of the Andean system in Peru. -Unfortunately time enough was not available for an extension of the trip -to these localities whose geologic characters still remain entirely -unknown. From the topographic aspects of the country, it is, however, -reasonably certain that the whole intervening depression between these -outlying ranges and the border of the main Cordillera, is filled with -inclined and now dissected and partly covered Tertiary strata. The -elevation of the upper surface does not, however, remain the same; it -appears to decrease steadily and the youngest Tertiary strata disappear -from view below the sediments of either the Pleistocene or the present -river gravels. In the more central parts of the depression occupied by -the Urubamba Valley, only knobs or ridges project here and there above -the general level. - - -_The Coastal Tertiary_ - -The Tertiary deposits of the Peruvian desert region southwest of the -Andes have many special features related to coastal deformation, changes -of climate, and great Andean uplifts. They lie between the west coast of -Peru at Camaná and the high, lava-covered country that forms the western -border of the Andes and in places are over a mile thick. They are -non-fossiliferous, cross-bedded, ripple-marked, and have abundant lenses -of conglomerate of all sizes. The beds rest upon an irregular floor -developed upon a varied mass of rocks. In some places the basement -consists of old strata, strongly deformed and eroded. In other places it -consists of a granite allied in character and probably in origin with -the old granite-gneiss of the Coast Range toward the west. Elsewhere the -rock is lava, evidently the earliest in the great series of volcanic -flows that form this portion of the Andes. - -The deposits on the western border of the Andes are excellently exposed -in the Majes Valley, one of the most famous in Peru, though its fame -rests rather upon the excellence and abundance of its vineyards and -wines than its splendid geologic sections. Its head lies near the base -of the snow-capped peaks of Coropuna; its mouth is at Camaná on the -Pacific, a hundred miles north of Mollendo. It is both narrow and deep; -one may ride across its floor anywhere in a half hour. In places it is a -narrow canyon. Above Cantas it is sunk nearly a mile below the level of -the desert upland through which it flows. Along its borders are exposed -basal granites, old sedimentaries, and lavas; inter-bedded with it are -other lavas that lie near the base of the great volcanic series; through -it still project the old granites of the Coast Range; and upon it have -been accumulated additional volcanic rocks, wind-blown deposits, and, -finally, coarse wash formed during the glacial period. From both the -variety of the formations, the small amount of marginal dissection, and -the excellent exposures made possible by the deep erosion and desert -climate, the Majes Valley is one of the most profitable places in Peru -for physiographic and geologic study. - -[Illustration: FIG. 171--Generalized sketch section to show the -structural relations of the Maritime Cordillera, the desert pampas, and -the Coast Range.] - -The most complete succession of strata (Tertiary) occurs just below -Cantas on the trail to Jaguey (Fig. 171). Upon a floor of -granite-gneiss, and alternating beds of quartzite and shale belonging to -an older series, are deposited heavy beds of red sandstone with many -conglomerate lenses. The sandstone strata are measurably deformed and -their upper surfaces moderately dissected. Upon them have been deposited -unconformably a thicker series of deposits, conglomerates, sandstones, -and finer wind-blown material. The basal conglomerate is very -coarse--much like beach material in both structure and composition, and -similar to that along and south of the present coast at Camaná. Higher -in the section the material is prevailingly sandy and is deposited in -regular beds from a few inches to a few feet in thickness. Near the top -of the section are a few hundred feet of strata chiefly wind deposited. -Unconformably overlying the whole series and in sharp contrast to the -fine wind-blown stuff below it, is a third series of coarse deposits -about five hundred feet thick. The topmost material, that forming the -surface of the desert upland, consists of wind-blown sand now shifted by -the wind and gathered into sand dunes or irregular drifts, banks of -white earth, "tierra blanca," and a pebble pavement a few inches thick. - -If the main facts of the above section are now summarized they will -facilitate an understanding of other sections about to be described, -inasmuch as the summary will in a measure anticipate our conclusions -concerning the origin of the deposits and their subsequent history. The -sediments in the Majes Valley between Cantas and Jaguey consist of three -series separated by two unconformities. The lowermost series is evenly -bedded and rather uniform in composition and topographic expression, -standing forth in huge cliffs several hundred feet high on the eastern -side of the valley. This lower series is overlain by a second series, -which consists of coarse conglomerate grading into sand and ultimately -into very fine fluffy wind-deposited sands and silts. The lower series -is much more deformed than the upper, showing that the deforming -movements of later geologic times have been much less intense than the -earlier, as if there had been a fading out or weakening of the deforming -agents. Finally there is a third series several hundred feet thick which -forms the top of the section. - -[Illustration: FIG. 172--Geologic relations of Coast Range, desert -deposits, and Maritime Cordillera at Moquegua, Peru. After G. I. Adams; -Bol. de Minas del Perú, Vol. 2, No. 4, 1906, p. 20.] - -[Illustration: FIG. 173--Sketch section to show structural details on -the walls of the Majes Valley near Aplao, looking south.] - -Three other sections may now be examined, one immediately below Cantas, -one just above, and one opposite Aplao. The section below Cantas is -shown in Fig. 173, and indicates a lower series of red sandstones -crossed by vertical faults and unconformably overlain by nearly -horizontal conglomerates, sandstones, etc., and the whole faulted again -with an inclined fault having a throw of nearly 25°. A white to gray -sandstone unconformably overlying the red sandstone is shown -interpolated between the lowermost and uppermost series, the only -example of its kind, however. No important differences in -lithographical character may be noted between these and the beds of the -preceding section. - -Again just above Cantas on the east side of the valley is a clean -section exposing about two thousand feet of strata in a half mile of -distance. The foundation rocks are old quartzites and shales in -regularly alternating beds. Upon their uneven upper surfaces are several -thousand feet of red sandstones and conglomerates, which are both folded -and faulted with the underlying quartzites. Above the red sandstones is -a thick series of gray sandstones and silts which makes the top of the -section and unconformably overlies the earlier series. - -A similar succession of strata was observed at Aplao, still farther up -the Majes Valley, Fig. 174. A greatly deformed and metamorphosed older -series is unconformably overlaid by a great thickness of younger strata. -The younger strata may be again divided into two series, a lower series -consisting chiefly of red sandstones and an upper consisting of gray to -yellow, and only locally red sands of finer texture and more uniform -composition. The two are separated by an erosion surface and only the -upper series is tilted regionally seaward with faint local deformation; -the lower series is both folded and faulted with overthrusts aggregating -several thousand feet of vertical and a half mile of horizontal -displacement. - -[Illustration: FIG. 174--The structural relations of the strata on the -border of the Majes Valley at Aplao, looking west. Field sketch from -opposite side of valley. Height of section about 3,000 feet; length -about ten miles.] - -The above sections all lie on the eastern side of the Majes Valley. From -the upper edge of the valley extensive views were gained of the strata -on the opposite side, and two sections, though they were not examined at -close range, are at least worth comparing with those already given. From -the narrows below Cantas the structure appears as in Figs. 175-176, and -shows a deforming movement succeeded by erosion in a lower series. The -upper series of sedimentary rock has suffered but slight deformation. A -still more highly deformed basal series occurs on the right of the -section, presumably the older quartzites. At Huancarqui, opposite Aplao, -an extensive view was gained of the western side of the valley, but the -lower Tertiary seems not to be represented here, as the upper undeformed -series rests unconformably upon a tilted series of quartzites and -slates. Farther up the Cantas valley (an hour's ride above Aplao) the -Tertiary rests upon volcanic flows or older quartzites or the -granite-gneiss exposed here and there along the valley floor. - -[Illustration: FIG. 175--Sketch section to show the structural details -of the strata on the south wall of the Majes Valley near Cantas. The -section is two miles long.] - -[Illustration: FIG. 176--Composite geologic section to show the -structural relations of the rocks on the western border of the Maritime -Cordillera. The inclined strata at the right bottom represent older -rocks; in places igneous, in other places sedimentary.] - -In no part of the sedimentaries in the Majes Valley were fossils found, -save in the now uplifted and dissected sands that overlie the upraised -terraces along the coast immediately south of Camaná and also back of -Mollendo. Like similar coastal deposits elsewhere along the Peruvian -littoral, the terrace sands are of Pliocene or early Pleistocene age. -The age of the deposits back of the Coast Range is clearly greater than -that of the coastal deposits, (1) since they involve two unconformities, -a mile or more of sediments, and now stand at least a thousand feet -above the highest Pliocene (or Pleistocene) in the Camaná Valley, and -(2) because the erosion history of the interior sediments may be -correlated with the physiographic history of the coastal terraces and -the correlation shows that uplift and dissection of the terraces and of -the interior deposits went hand in hand, and that the deposits on the -terraces may similarly be correlated with alluvial deposits in the -valley. - -We shall now see what further ground there is for the determination of -the age of these sediments. Just below Chuquibamba, where they first -appear, the sediments rest upon a floor of volcanic and older rock -belonging to the great field now known from evidence in many localities -to have been formed in the early Tertiary, and here known to be -post-Cretaceous from the relations between Cretaceous limestones and -volcanics in the Cotahuasi Valley (see p. 247). Although volcanic flows -were noted interbedded with the desert deposits, these are few in -number, insignificant in volume, and belong to the top of the volcanic -series. The same may be said of the volcanic flows that locally overlie -the desert deposits. We have then definite proof that the sandstones, -conglomerates, and related formations of the Majes Valley and bordering -uplands are older than the Pliocene or early Pleistocene and younger -than the Cretaceous and the older Tertiary lavas. Hence it can scarcely -be doubted that they represent a considerable part of the Tertiary -period, especially in view of the long periods of accumulation which the -thick sediments represent, and the additional long periods represented -by the two well-marked unconformities between the three principal groups -of strata. - -If we now trace the physical history of the region we have first of all -a deep depression between the granite range along the coast and the -western flank of the Andes. Here and there, as in the Vitor, the Majes, -and other valleys, there were gaps through the Coast Range. Nowhere did -the relief of the coastal chain exceed 5,000 feet. The depression had -been partly filled in early geologic (probably early Paleozoic) time by -sediments later deformed and metamorphosed so that they are now -quartzites and shales. The greater resistance of the granite of the -Coast Range resulted in superior relief, while the older deformed -sedimentaries were deeply eroded, with the result that by the beginning -of the Tertiary the basin quality of the depression was again -emphasized. All these facts are expressed graphically in Fig. 171. On -the western flanks of the granite range no corresponding sedimentary -deposits are found in this latitude. The sea thus appears to have stood -farther west of the Coast Range in Paleozoic times than at present. - -[Illustration: FIG. 177--Composite structure section at Aplao.] - -For the later history it is necessary to assemble the various Tertiary -sections described on the preceding pages. First of all we recognize -three quite distinct types of accumulations, for which we shall have to -postulate three sets of conditions and possibly three separate agents. -The first or lowermost consists of even-bedded deposits of red and gray -sandstones, the former color predominating. The material is in general -well-sorted save locally, where lenses and even thin beds of -conglomerate have been developed. There is, however, about the whole -series a uniformity and an orderliness in striking contrast to the -coarse, cross-bedded, and irregular material above the unconformity. On -their northeastern or inner margin the sandstones are notably coarser -and thicker, a natural result of proximity to the mountains, the source -of the material. The general absence of wind-blown deposits is marked; -these occur entirely along the eastern and northern portions of the -deposits and are recognized (1) by their peculiar cross-bedding, and (2) -by the fact that the cross-bedding is directed northeastward in a -direction contrary to the regional dip of the series, a condition -attributable to the strong sea breezes that prevail every afternoon in -this latitude. - -The main body of the material is such as might be deposited on the wide -flood plains of piedmont streams during a period of prolonged erosion -on surrounding highlands that served as the feeding grounds of the -streams. The alternations in the character of the deposits, alternations -which, in a general view, give a banded appearance to the rock, are -produced by successions of beds of fine and coarse material, though all -of it is sandstone. Such successions are probably to be correlated with -seasonal changes in the volume and load of the depositing streams. - -To gain an idea of the conditions of deposition we may take the -character of the sediments as described above, and from them draw -deductions as to the agents concerned and the manner of their action. - -We may also apply to the area the conclusions drawn from the study of -similar deposits now in process of formation. We have between the coast -ranges of northern Chile and the western flanks of the Cordillera -Sillilica, probably the best example of piedmont accumulation in a dry -climate that the west coast of South America affords. - -Along the inner edge of the Desert of Tarapacá, roughly between the -towns of Tarapacá and Quillagua, Chile, the piedmont gravels, sands, -silts, and muds extend for over a hundred miles, flanking the western -Andes and forming a transition belt between these mountains and the -interior basins of the coast desert. The silts and muds constitute the -outer fringe of the piedmont and are interrupted here and there where -sands are blown upon them from the higher portions of the piedmont, or -from the desert mountains and plains on the seaward side. Practically no -rain falls upon the greater part of the desert and the only water it -receives is that borne to it by the piedmont streams in the early -summer, from the rains and melted snows of the high plateau and -mountains to the eastward. These temporary streams spread upon the outer -edge of the piedmont a wide sheet of mud and silt which then dries and -becomes cracked, the curled and warped plates retaining their character -until the next wet season or until covered with wind-blown sand. The -wind-driven sand fills the cracks in the muds and is even drifted under -the edges of the upcurled plates, filling the spaces completely. Over -this combined fluvial and æolian deposit is spread the next layer of -mud, which frequently is less extensive than the earlier deposits, thus -giving abundant opportunity for the observation of the exact manner of -burial of the older sand-covered stratum. - -Now while the alternations are as marked in Peru as in Chile, it is -noteworthy that the Tertiary material in Peru is not only coarse -throughout, even to the farthest limits of the piedmont, but also that -the alternating beds are thick. Moreover, there are only the most feeble -evidences of wind action in the lowermost Tertiary series. I was -prepared to find curled plates, wind-blown sands, and muds and silts, -but they are almost wholly absent. It is, therefore, concluded that the -dryness was far less extreme than it is today and that full streams of -great competency flowed vigorously down from the mountains and carried -their loads to the inner border of the Coast Range and in places to the -sea. - -The fact that the finer material is _sandy_, not clayey or silty, that -it almost equals in thickness the coarser layers, and that its -distribution appears to be co-extensive with the coarser, warrants the -conclusion that it too was deposited by competent streams of a type far -different from the withering streams associated with piedmont deposits -in a thoroughly arid climate like that of today. Both in the second -Tertiary series and on the present surface are such clear examples of -deposits made in a drier climate as to leave little doubt that the -earliest of the Tertiary strata of the Majes Valley were deposited in a -time of far greater rainfall than the present. It is further concluded -that there was increasing dryness, as shown by hundreds of feet of -wind-blown sand near the top of the section. But the growing dryness was -interrupted by at least one period of greater precipitation. Since that -time there has been a return to the dry climate of a former epoch. - -Uplift and erosion of the earliest of the Tertiary deposits of the Majes -Valley is indicated in two ways: (1) by the deformed character of the -beds, and (2) by the ensuing coarse deposits which were derived from the -invigorated streams. Without strong deformations it would not be -possible to assign the increased erosion so confidently to uplift; with -the coarse deposits that succeed the unconformity we have evidence of -accumulation under conditions of renewed uplift in the mountains and of -full streams competent to remove the increasing load. - -It is in the character of the sediments toward the top of the Tertiary -that we have the clearest evidence of progressive desiccation of the -climate of the region. The amount of wind-blown material steadily -increases and the uppermost five hundred feet is composed predominantly, -and in places exclusively, of this material. The evidences of wind -action lie chiefly in the fine (in places fluffy) nature of the -deposits, their uniform character, and in the tangency of the layers -with respect to the surface on which they were deposited. There are -three diagnostic structural features of great importance: the very steep -dip of the fine laminae; the peculiar and harmonious blending of their -contacts; the manner in which the highly inclined laminae cut off and -succeed each other, whereby quite bewildering changes in the direction -of dip of the inclined beds are brought about on any exposed plane. Some -of these features require further discussion. - -It is well known that the front of a sand dune generally consists of -sand deposited on a slope inclined at the angle of repose, say between -30° and 35°, and rolled into place up the long back slope of the dune by -the wind. It has not, however, been generally recognized that the angle -of repose may be exceeded (a) when there exists a strong back eddy or -(b) when the wind blows violently and for a short time in the opposite -direction. In either case sand is carried up the short steep slope of -the dune front and accumulated at an angle not infrequently running up -to 43° and 48° and locally, and under the most favorable circumstances, -in excess of 50°. The conditions under which these steep angles are -attained are undoubtedly not universal, but they can be found in some -parts of almost any desert in the world. They appear not to be present -where the sand grains are of uniform size throughout, since that leads -to rolling. They are found rather where there is a certain limited -variation in size that promotes packing. Packing and the development of -steep slopes are also facilitated in parts of the coastal desert of Peru -by a cloud canopy that hangs over the desert in the early morning, that -in the most favorable places moistens even the dune surfaces and that -has least penetration on the steep semi-protected dune fronts. Sand -later blown up the dune front or rolled down from the dune crest is -encouraged to remain near the cornice on an abnormally steep slope by -the attraction which the slightly moister sand has for the dry grains -blown against it. Since dunes travel and since their front layers, -formed on steep slopes, are cut off to the level of the surface in the -rear of the dune, it follows that the steepest dips in exposed sections -are almost always less than those in existing dunes. Exceptions to the -rule will be noted in filled hollows not re-excavated until deeply -covered by wind-blown material. These, re-exposed at the end of a long -period of wind accumulation, may exhibit even the maximum dips of the -dune cornices. Such will be conspicuously the case in sections in -aggraded desert deposits. On the border of the Majes Valley, from 400 to -500 feet of wind-accumulated deposits may be observed, representing a -long period of successive dune burials. - -The peculiar blending of the contact lines of dune laminae, related to -the tangency commonly noted in dune accumulations, is apparently due to -the fact that the wind does not require a graded surface to work on, but -blows uphill as well as down. It is present on both the back-slope and -the front-slope deposits. Its finest expression appears to be in -districts where the dune material was accumulated by a violent wind -whose effects the less powerful winds could not destroy. - -It is to the ability of the wind to transport material against, as well -as with, gravity, that we owe the third distinct quality of dune -material, the succession of flowing lines, in contrast to the succession -of now flat-lying now steeply inclined beds characteristic of -cross-bedded material deposited by water. One dune travels across the -face of the country only to be succeeded by another.[54] Even if wind -aggradation is in progress, the plain-like surface in the rear of a dune -may be excavated to the level of steeply inclined beds upon whose -truncated outcrop other inclined beds are laid, Fig. 178. The contrast -to these conditions in the case of aggradation by water is so clearly -and easily inferred that space will not be taken to point them out. It -is also true as a corollary to the above that the greater part of a body -of wind-drifted material will consist of cross-bedded layers, and not a -series of evenly divided and alternating flat-lying and cross-bedded -layers which result from deposition in active and variable currents of -water. - -The caution must of course be observed that wind action and water action -may alternate in a desert region, as already described in Tarapacá in -northern Chile, so that the whole of a deposit may exhibit an -alternation of cross-bedded and flat-lying layers; but the former only -are due to wind action, the latter to water action. - -Finally it may be noted that the sudden, frequent, and diversified dips -in the cross-bedding are peculiarly characteristic of wind action. -Although one sees in a given cross-section dips apparently directed only -toward the left or the right, excavation will supply a third dimension -from which the true dips may be either observed or calculated. These -show an almost infinite variety of directions of dip, even in restricted -areas, a condition due to the following causes: - -(1) the curved fronts of sand dunes, which produce dips concentric with -respect to a point and ranging through 180° of arc; (2) the irregular -character of sand dunes in many places, a condition due in turn to (a) -the changeful character of the strong wind (often not the prevailing -wind) to which the formation of the dunes is due, and (b) the influence -of the local topography upon wind directions within short distances or -upon winds of different directions in which a slight change in wind -direction is followed by a large change in the local currents; (3) the -fact that all combinations are possible between the erosion levels of -the wind in successive generations of dunes blown across a given area, -hence _any_ condition at a given level in a dune may be combined with -_any other_ condition of a succeeding dune; (4) variations in the sizes -of successive dunes will lead to further contrasts not only in the -scale of the features but also in the direction and amount of the dips. - -[Illustration: FIG. 178--Plan and cross-sections of superimposed sand -dunes of conventional outline. In the sections, dune _A_ is supposed to -have left only a small basal portion to be covered by dune _B_. In the -same way dune _C_ has advanced to cover both _A_ and _B_. The basal -portions that have remained are exaggerated vertically in order to -display the stratification. It is obviously not necessary that the dunes -should all be of the same size and shape and advancing in the same -direction in order to have the tangential relations here displayed. Nor -need the aggrading material be derived from true dunes. The results -would be the same in the case of sand _drifts_ with their associated -wind eddies. All bedded wind-blown deposits would have the same general -relations. No two successive deposits, no matter from what direction the -successive drifts or dunes travel, would exactly correspond in direction -and amount of dip.] - -Finally, we may note that a section of dune deposits has a distinctive -feature not exhibited by water deposits. If the foreset beds of a -cross-bedded water deposit be exposed in a plane parallel to the strike -of the beds, the beds will appear to be horizontal. They could not then -be distinguished from the truly horizontal beds above and below them. -But the conditions of wind deposition we have just noted, and chiefly -the facts expressed by Fig. 178, make it impossible to select a position -in which both tangency and irregular dips are not well developed in a -wind deposit. I believe that we have in the foregoing facts and -inferences a means for the definite separation of these two classes of -deposits. Difficulties will arise only when there is a quick succession -of wind and water action in time, or where the wind produces powerful -and persistent effects without the actual formation of dunes. - -The latest known deposits in the coastal region are found surmounting -the terrace tops along the coast between Camaná and Quilca, where they -form deposits several hundred feet thick in places. The age of these -deposits is determined by fossil evidence, and is of extraordinary -interest in the determination of the age of the great terraces upon -which they lie. They consist of alternating beds of coarse and fine -material, the coarser increasing in thickness and frequency toward the -bottom of the section. It is also near the bottom of the section that -fossils are now found; the higher members are locally saline and -throughout there is a marked inclination of the beds toward the present -shore. The deposits appear not to have been derived from the underlying -granite-gneiss. They are distributed most abundantly near the mouths of -the larger streams, as near the Vitor at Quilca, and the Majes at -Camaná. Elsewhere the terrace summit is swept clean of waste, except -where local clay deposits lie in the ravines, as back of Mollendo and -where "tierras blancas" have been accumulated by the wind. - -These coastal deposits were laid down upon a dissected terrace up to -five miles in width. The degree of dissection is variable, and depends -upon the relation of the through-flowing streams to the Coast Range. The -Vitor and the Majes have cut down through the Coast Range, and locally -removed the terrace; smaller streams rising on the flanks of the Coast -Range either die out near the foot of the range or cross it in deep and -narrow valleys. The present drainage on the seaward slopes of the Coast -Range is entirely ineffective in reaching the sea, as was seen in 1911, -the wettest season known on the coast in years and one of the wettest -probably ever observed on this coast by man. - -In consequence of their deposition on a terrace that ranges in elevation -from zero to 1,500 feet above sea level, the deposits of the coast are -very irregularly disposed. But in consequence of their great bulk they -have a rather smooth upper surface, gradation having been carried to the -point where the irregularities of the dissected terrace were smoothed -out. Their general uniformity is broken where streams cross them, or -where streams crossed them during the wetter Pleistocene. Their -elevation, several hundred feet above sea level, is responsible for the -deep dissection of their coastal margin, where great cliffs have been -cut. - - -PLEISTOCENE - -The broad regional uplift of the Peruvian Andes in late Tertiary and in -Pleistocene times carried their summits above the level of perpetual -snow. It is still an open question whether or not uplift was -sufficiently great in the early Pleistocene to be influenced by the -first glaciations of that period. As yet, there are evidences of only -two glacial invasions, and both are considered late events on account of -the freshness of their deposits and the related topographic forms. The -coarse deposits--nearly 500 feet thick--that form the top of the desert -section described above clearly indicate a wetter climate than prevailed -during the deposition of the several hundred feet of wind-blown deposits -beneath them. But if our interpretation be correct these deposits are of -late Tertiary age, and their character and position are taken to -indicate climatic changes in the Tertiary. They may have been the mild -precursors of the greater climatic changes of glacial times. Certain it -is that they are quite unlike the mass of the Tertiary deposits. On the -other hand they are separated from the deposits of known glacial age by -a time interval of great length--an epoch in which was cut a benched -canyon nearly a mile deep and three miles wide. They must, therefore, -have been formed when the Andes were thousands of feet lower and unable -to nourish glaciers. It was only after the succeeding uplifts had raised -the mountain crests well above the frost line that the records of -oscillating climates were left in erratic deposits, troughed valleys, -cliffed cirques and pinnacled divides. - -The glacial forms are chiefly at the top of the country; the glacial -deposits are chiefly in the deep valleys that were carved before the -colder climate set in. The rock waste ground up by the ice was only a -small part of that delivered to the streams in glacial times. Everywhere -the wetter climate resulted in the partial stripping of the residual -soil gathered upon the smooth mature slopes formed during the long -Tertiary cycle of erosion. This moving sheet of waste as well as the -rock fragments carried away from the glacier ends were strewn along the -valley floors, forming a deep alluvial fill. Thereby the canyon floors -were rendered habitable. - -In the chapters on human geography we have already called attention to -the importance of the U-shaped valleys carved by the glaciers. Their -floors are broad and relatively smooth. Their walls restrain the live -stock. They are sheltered though lofty. But all the human benefits -conferred by ice action are insignificant beside those due to the -general shedding of waste from the cold upper surfaces to the warm -levels of the valley floors. The alluvium-filled valleys are the seats -of dense populations. In the lowest of them tropical and sub-tropical -products are raised, like sugar-cane and cotton, in a soil that once lay -on the smooth upper slopes of mountain spurs or that was ground fine on -the bed of an Alpine glacier. - -[Illustration: FIG. 179--Snow fields on the summit of the Cordillera -Vilcapampa near Ollantaytambo. A huge glacier once lay in the steep -canyon in the background and descended to the notched terminal moraine -at the canyon mouth. In places the glacier was over a thousand feet -thick. From the terminal moraine an enormous alluvial fan extends -forward to the camera and to the opposite wall of the Urubamba Valley. -It is confluent with other fans of the same origin. See Fig. 180. In the -foreground are flowers, shrubs, and cacti. A few miles below Urubamba at -11,500 feet.] - -[Illustration: FIG. 180--Urubamba Valley between Ollantaytambo and -Torontoy, showing (1) more moderate upper slopes and steeper lower -slopes of the two-cycle mountain spurs; (2) the extensive alluvial -deposits of the valley, consisting chiefly of confluent alluvial fans -heading in the glaciated mountains on the left. See Fig. 179.] - -[Illustration: FIG. 181--Glacial features of the Central Ranges (see -Fig. 204). Huge lateral moraines built by ice streams tributary to the -main valley north of Chuquibambilla. That the tributaries persisted long -after the main valley became free of ice is shown by the descent of the -lateral moraines over the steep border of the main valley and down to -the floor of it.] - -The Pleistocene deposits fall into three well-defined groups: (1) -glacial accumulations at the valley heads, (2) alluvial deposits in -the valleys, and (3) lacustrine deposits formed on the floors of -temporary lakes in inclosed basins. Among these the most variable in -form and composition are the true glacier-laid deposits at the valley -heads. The most extensive are the fluvial deposits accumulated as valley -fill throughout the entire Andean realm. Though important enough in some -respects the lacustrine deposits are of small extent and of rather local -significance. Practically none of them fall within the field of the -present expedition; hence we shall describe only the first two classes. - -The most important glacial deposits were accumulated in the eastern part -of the Andes as a result of greater precipitation, a lower snowline, and -catchment basins of larger area. In the Cordillera Vilcapampa glaciers -once existed up to twelve and fifteen miles in length, and those several -miles long were numerous both here and throughout the higher portions of -the entire Cordillera, save in the belt of most intense volcanic action, -which coincides with the driest part of the Andes, where the glaciers -were either very short or wanting altogether. - -Since vigorous glacial action results in general in the cleaning out of -the valley heads, no deposits of consequence occur in these locations. -Down valley, however, glacial deposits occur in the form of terminal -moraines of recession and ground moraines. The general nature of these -deposits is now so well known that detailed description seems quite -unnecessary except in the case of unusual features. - -It is noteworthy that the moraines decrease in size up valley since each -valley had been largely cleaned out by ice action before the retreat of -the glacier began. Each lowermost terminal moraine is fronted by a great -mass of unsorted coarse bowldery material forming a fill in places -several hundred feet thick, as below Choquetira and in the Vilcapampa -Valley between Vilcabamba and Puquiura. This bowldery fill is quite -distinct from the long, gently inclined, and stratified valley train -below it, or the marked ridge-like moraine above it. It is in places a -good half mile in length. Its origin is believed to be due to an -overriding action beyond the last terminal moraine at a time when the -ice was well charged with débris, an overriding not marked by morainal -accumulations, chiefly because the ice did not maintain an extreme -position for a long period. - -In the vicinity of the terminal moraines the alluvial valley fill is -often so coarse and so unorganized as to look like till in the cut banks -along the streams, though its alluvial origin is always shown by the -topographic form. This characteristic is of special geologic interest -since the form may be concealed through deposition or destroyed by -erosion, and no condition but the structure remain to indicate the -manner of origin of the deposit. In such an event it would not be -possible to distinguish between alluvium and till. The gravity of the -distinction appears when it is known that such apparently unsorted -alluvium may extend for several miles forward of a terminal moraine, in -the shape of a widespreading alluvial fan apparently formed under -conditions of extremely rapid aggradation. I suppose it would not be -doubted in general that a section of such stony, bowldery, unsorted -material two miles long would have other than a glacial origin, yet such -may be the case. Indeed, if, as in the Urubamba Valley, a future section -should run parallel to the valley across the heads of a great series of -fans of similar composition, topographic form, and origin, it would be -possible to see many miles of such material. - -The depth of the alluvial valley fill due to tributary fan accumulation -depends upon both the amount of the material and the form of the valley. -Below Urubamba in the Urubamba Valley a fine series is displayed, as -shown in Fig. 180. The fans head in valleys extending up to snow-covered -summits upon whose flanks living glaciers are at work today. Their heads -are now crowned by terminal moraines and both moraines and alluvial fans -are in process of dissection. The height and extent of the moraines and -the alluvial fans are in rough proportion and in turn reflect the -height, elevation, and extent of the valley heads which served as fields -of nourishment for the Pleistocene glaciers. Where the fans were -deposited in narrow valleys the effect was to increase the thickness of -the deposits at the expense of their area, to dam the drainage lines or -displace them, and to so load the streams that they have not yet -cleared their beds after thousands of years of work under torrential -conditions. - -Below Urubamba the alluvial fans entering the main valley from the east -have pushed the river against its western valley wall, so that the river -flows on one side against rock and on the other against a hundred feet -of stratified material. In places, as at the head of the narrows on the -valley trail to Ollantaytambo, a flood plain has been formed in front of -the scarp cut into the alluvium, while the edge of the dissected -alluvial fans has been sculptured into erosion forms resembling -bad-lands topography. On the western side of the valley the alluvial -fans are very small, since they are due to purely local accumulations of -waste from the edge of the plateau. Glaciation has here displaced the -river. Its effects will long be felt in the disproportionate erosion of -the western wall of the valley. - -By far the most interesting of the deposits of glacial time are those -laid down on the valley floors in the form of an alluvial fill. Though -such deposits have greater thickness as a rule near the nourishing -moraines or bordering alluvial fans at the lower ends of the valleys, -they are everywhere important in amount, distinctive in topographic -form, and of amazingly wide extent. They reach far into and possibly -across the Amazon basin, they form a distinct though small piedmont -fringe along the eastern base of the Andes, and they are universal -throughout the Andean valleys. That a deposit of such volume--many times -greater than all the material accumulated in the form of high-level -alluvial fans or terminal moraines--should originate in a tropical land -in a region that suffered but limited Alpine glaciation vastly increases -its importance. - -[Illustration: FIG. 182--Dissected alluvial fans on the border of the -Urubamba Valley near Hacienda Chinche. A Characteristic feature of the -valleys of the Peruvian Andes below the zone of glaciation but within -the limits of its aggraditional effects. Through alluviation the valleys -and basins of the Andean Cordillera, and vast areas of the great Amazon -plains east of it, felt the effects of the glacial conditions of a past -age.] - -The fill is composed of both fine and coarse material laid down by water -in steep valley floors to a depth of many feet. It breaks the steep -slope of each valley, forming terraces with pronounced frontal scarps -facing the river. On the raw bluffs at the scarps made by the -encroaching stream good exposures are afforded. At Chinche in the -Urubamba Valley above Santa Ana, the material is both sand and clay with -an important amount of gravel laid down with steep valleyward -inclination and under torrential conditions; so that within a given bed -there may be an apparent absence of lamination. Almost identical -conditions are exhibited frequently along the railway to Cuzco in the -Vilcanota Valley. The material is mixed sand and gravel, here and there -running to a bowldery or stony mass where accessions have been received -from some source nearby. It is modified along its margin not only in -topographic form but also in composition by small tributary alluvial -fans, though these in general constitute but a small part of the total -mass. At Cotahuasi, Fig. 29, there is a remarkable fill at least four -hundred feet deep in many places where the river has exposed fine -sections. The depth of the fill is, however, not determined by the -height of the erosion bluffs cut into it, since the bed of the river is -made of the same material. The rock floor of the valley is probably at -least an additional hundred feet below the present level of the river. - -[Illustration: FIG. 183--Two-cycle slopes and alluvial fill between -Iluichihua and Chuquibambilla. The steep slopes on the inner valley -border are in many places vertical and rock cliffs are everywhere -abundant. Mature slopes have their greatest development here between -13,500 and 15,000 feet (4,110 to 4,570 m.). Steepest mature slopes run -from 15° to 21°. Least steep are the almost level spur summits. The -depths of the valley fill must be at least 300, and may possibly be 500 -feet. The break between valley fill and steep slopes is most pronounced -where the river runs along the valley wall or undercuts it; least -pronounced where alluvial fans spread out from the head of some ravine. -It is a bowldery, stony fill almost everywhere terraced and cultivated.] - -Similar conditions are well displayed at Huadquiña, where a fine series -of terraces at the lower end of the Torontoy Canyon break the descent of -the environing slopes; also in the Urubamba Valley below Rosalina, and -again at the edge of the mountains at the Pongo de Mainique. It is -exhibited most impressively in the Majes Valley, where the bordering -slopes appear to be buried knee-deep in waste, and where from any -reasonable downward extension of rock walls of the valley there would -appear to be at least a half mile of it. It is doubtful and indeed -improbable that the entire fill of the Majes Valley is glacial, for -during the Pliocene or early Pleistocene there was a submergence which -gave opportunity for the partial filling of the valley with non-glacial -alluvium, upon which the glacial deposits were laid as upon a flat and -extensive floor that gives an exaggerated impression of their depth. -However, the head of the Majes Valley contains at least six hundred feet -and probably as much as eight hundred feet of alluvium now in process of -dissection, whose coarse texture and position indicates an origin under -glacial conditions. The fact argues for the great thickness of the -alluvial material of the lower valley, even granting a floor of Pliocene -or early Pleistocene sediments. The best sections are to be found just -below Chuquibamba and again about halfway between that city and Aplao, -whereas the best display of the still even-floored parts of the valley -are between Aplao and Cantas, where the braided river still deposits -coarse gravels upon its wide flood plain. - - - - -CHAPTER XVI - -GLACIAL FEATURES - -THE SNOWLINE - - -South America is classical ground in the study of tropical snowlines. -The African mountains that reach above the snowline in the equatorial -belt--Ruwenzori, Kibo, and Kenia--have only been studied recently -because they are remote from the sea and surrounded by bamboo jungle and -heavy tropical forest. On the other hand, many of the tropical mountains -of South America lie so near the west coast as to be visible from it and -have been studied for over a hundred years. From the days of Humboldt -(1800) and Boussingault (1825) down to the present, observations in the -Andes have been made by an increasing number of scientific travelers. -The result is a large body of data upon which comparative studies may -now be profitably undertaken. - -Like scattered geographic observations of many other kinds, the earlier -studies on the snowline have increased in value with time, because the -snowline is a function of climatic elements that are subject to periodic -changes in intensity and cannot be understood by reference to a single -observation. Since the discovery of physical proofs of climatic changes -in short cycles, studies have been made to determine the direction and -rate of change of the snowline the world over, with some very striking -results. - -It has been found[55] that the changes run in cycles of from thirty to -thirty-five years in length and that the northern and southern -hemispheres appear to be in opposite phase. For example, since 1885 the -snowline in the southern hemisphere has been decreasing in elevation in -nine out of twelve cases by the average amount of nine hundred feet. -With but a single exception, the snowline in the northern hemisphere -has been rising since 1890 with an average increase of five hundred feet -in sixteen cases. To be sure, we must recognize that the observations -upon which these conclusions rest have unequal value, due both to -personal factors and to differences in instrumental methods, but that in -spite of these tendencies toward inequality they should agree in -establishing a general rise of the snowline in the northern hemisphere -and an opposite effect in the southern is of the highest significance. - -It must also be realized that snowline observations are altogether too -meager and scattered in view of the abundant opportunities for making -them, that they should be standardized, and that they must extend over a -much longer period before they attain their full value in problems in -climatic variations. Once the possible significance of snowline changes -is appreciated the number and accuracy of observations on the elevation -and local climatic relations of the snowline should rapidly increase. - -In 1907 I made a number of observations on the height of the snowline in -the Bolivian and Chilean Andes between latitudes 17° and 20° south, and -in 1911 extended the work northward into the Peruvian Andes along the -seventy-third meridian. It is proposed here to assemble these -observations and, upon comparison with published data, to make a few -interpretations. - -From Central Lagunas, Chile, I went northeastward via Pica and the -Huasco Basin to Llica, Bolivia, crossing the Sillilica Pass in May, -1907, at 15,750 feet (4,800 m.). Perpetual snow lay at an estimated -height of 2,000-2,500 feet above the pass or 18,000 feet (5,490 m.) -above the sea. Two weeks later the Huasco Basin, 14,050 feet (4,280 m.), -was covered a half-foot deep with snow and a continuous snow mantle -extended down to 13,000 feet. Light snows are reported from 12,000 feet, -but they remain a few hours only and are restricted to the height of -exceptionally severe winter seasons (June and early July). Three or four -distant snow-capped peaks were observed and estimates made of the -elevation of the snowline between the Cordillera Sillilica and Llica on -the eastern border of the Maritime Cordillera. All observations agreed -in giving an elevation much in excess of 17,000 feet. In general the -values run from 18,000 to 19,000 feet (5,490 to 5,790 m.). Though the -bases of these figures are estimates, it should be noted that a large -part of the trail lies between 14,000 and 16,000 feet, passing mountains -snow-free at least 2,000 to 3,000 feet higher, and that for general -comparisons they have a distinct value. - -In the Eastern Cordillera of Bolivia, snow was observed on the summit of -the Tunari group of peaks northwest of Cochabamba. Steinmann, who -visited the region in 1904, but did not reach the summit of the Tunari -group of peaks, concludes that the limit of perpetual snow should be -placed above the highest point, 17,300 (5,270 m.); but in July and -August, 1907, I saw a rather extensive snow cover over at least the -upper 1,000 feet, and what appeared to be a very small glacier. Certain -it is that the Cochabamba Indians bring clear blue ice from the Tunari -to the principal hotels, just as ice is brought to Cliza from the peaks -above Arani. On these grounds I am inclined to place the snowline at -17,000 feet (5,180 m.) near the eastern border of the Eastern -Cordillera, latitude 17° S. At 13,000 feet, in July, 1907, snow occurred -in patches only on the pass called Abre de Malaga, northeast of Colomi, -13,000 feet, and fell thickly while we were descending the northern -slopes toward Corral, so that in the early morning it extended to the -cold timber line at 10,000 feet. In a few hours, however, it had -vanished from all but the higher and the shadier situations. - -In the Vilcanota knot above the divide between the Titicaca and -Vilcanota hydrographic systems, the elevation of the snowline was -16,300+ feet (4,970 m.) in September, 1907. On the Cordillera Real of -Bolivia it is 17,000 to 17,500 feet on the northeast, but falls to -16,000 feet on the southwest above La Paz. In the first week of July, -1911, snow fell on the streets of Cuzco (11,000 feet) and remained for -over an hour. The heights north of San Geronimo (16,000 feet) miss the -limit of perpetual snow and are snow-covered only a few months each -year. - -In taking observations on the snowline along the seventy-third meridian -I was fortunate enough to have a topographer the heights of whose -stations enabled me to correct the readings of my aneroid barometer -whenever these were taken off the line of traverse. Furthermore, the -greater height of the passes--15,000 to 17,600 feet--brought me more -frequently above the snowline than had been the case in Bolivia and -Chile. More detailed observations were made, therefore, not only upon -the elevation of the snowline from range to range, but also upon the -degree of canting of the snowline on a given range. Studies were also -made on the effect of the outline of the valleys upon the extent of the -glaciers, the influence on the position of the snowline of mass -elevation, precipitation, and cloudiness. - -Snow first appears at 14,500 feet (4,320 m.) on the eastern flanks of -the Cordillera Vilcapampa, in 13° south latitude. East of this group of -ridges and peaks as far as the extreme eastern border of the mountain -belt, fifty miles distant, the elevations decrease rapidly to 10,000 -feet and lower, with snow remaining on exceptionally high peaks from a -few hours to a few months. In the winter season snow falls now and then -as low as 11,500 feet, as in the valley below Vilcabamba pueblo in early -September, 1911, though it vanishes like mist with the appearance of the -sun or the warm up-valley winds from the forest. Storms gather daily -about the mountain summits and replenish the perpetual snow above 15,000 -feet. In the first pass above Puquiura we encountered heavy snow banks -on the northeastern side a hundred feet below the pass (14,500 feet), -but on the southwestern or leeward side it is five hundred feet lower. -This distribution is explained by the lesser insolation on the -southwestern side, the immediate drifting of the clouds from the -windward to the leeward slopes, and to the mutual intensification of -cause and effect by topographic changes such as the extension of -collecting basins and the steeping of the slopes overlooking them with a -corresponding increase in the duration of shade. - -It is well known that with increase of elevation and therefore of the -rarity of the air there is less absorption of the sun's radiant energy, -and a corresponding increase in the degree of insolation. It follows, -therefore, that at high altitudes the contrasts between sun and shade -temperatures will increase. Frankland[56] has shown that the increase -may run as high as 500 per cent between 100 to 10,000 feet above the -sea. I have noted a fall of temperature of 15° F. in six minutes, due to -the obscuring of the sun by cloud at an elevation of 16,000 feet above -Huichihua in the Central Ranges of Peru. Since the sun shines -approximately half the time in the snow-covered portions of the -mountains and since the tropical Andes are of necessity snow-covered -only at lofty elevations, this contrast between shade and sun -temperatures is by far the most powerful factor influencing differences -in elevation of the snowline in Peru. - -To the drifting of the fallen snow is commonly ascribed a large portion -of this contrast. I have yet to see any evidence of its action near the -snowline, though I have often observed it, especially under a high wind -in the early morning hours at considerable elevations above the -snowline, as at the summits of lofty peaks. It appears that the lower -ranges bearing but a limited amount of snow are not subject to drifting -because of the wetness of the snow, and the fact that it is compacted by -occasional rains and hail storms. Only the drier snow at higher -elevations and under stronger winds can be effectively dislodged. - -The effect of unequal distribution of precipitation on the windward and -leeward slopes of a mountain range is in general to depress the snowline -on the windward slopes where the greater amount falls, but this may be -offset in high altitudes by temperature contrasts as in the westward -trending Cordillera Vilcapampa, where north and south slopes are in -opposition. If the Cordillera Vilcapampa ran north and south we should -have the windward and leeward slopes equally exposed to the sun and the -snowline would lie at a lower elevation on the eastern side. Among all -the ranges the slopes have decreasing precipitation to the leeward, that -is, westerly. The second and third passes, between Arma and Choquetira, -are snow-free (though their elevations equal those of the first pass) -because they are to leeward of the border range, hence receive less -precipitation. The depressive effect of increased precipitation on the -snowline is represented by A-B, Fig. 184; in an individual range the -effect of heavier precipitation may be offset by temperature contrasts -between shady and sunny slopes, as shown by the line a-b in the same -figure. - -The degree of canting of the snowline on opposite slopes of the -Cordillera Vilcapampa varies between 5° and 12°, the higher value being -represented four hours southwest of Arma on the Choquetira trail, -looking northeast. A general view of the Cordillera looking east at this -point (Fig. 186), shows the appearance of the snowline as one looks -along the flanks of the range. In detail the snowline is further -complicated by topography and varying insolation, each spur having a -snow-clad and snow-free aspect as shown in the last figure. The degree -of difference on these minor slopes may even exceed the difference -between opposite aspects of the range in which they occur. - -[Illustration: FIG. 184--To illustrate the canting of the snowline. -_A-B_ is the snowline depressed toward the north (right) in response to -heavier precipitation. The line _a-b_ represents a depression in the -opposite direction due to the different degree of insolation on the -northern (sunny) and southern (shady) slopes.] - -To these diversifying influences must be added the effect of warm -up-valley winds that precede the regular afternoon snow squalls and that -melt the latest fall of snow to exceptionally high elevations on both -the valley floor and the spurs against which they impinge. The influence -of the warmer air current is notably confined to the heads of those -master valleys that run down the wind, as in the valley heading at the -first pass, Cordillera Vilcapampa, and at the heads of the many valleys -terminating at the passes of the Maritime Cordillera. Elsewhere the -winds are dissipated in complex systems of minor valleys and their -effect is too well distributed to be recognized. - -It is clear from the conditions of the problem as outlined on preceding -pages that the amount of canting may be expressed in feet of difference -of the snowline on opposite sides of a range or in degrees. The former -method has, heretofore, been employed. It is proposed that this method -should be abolished and degrees substituted, on the following grounds: -Let _A_ and _B_, Fig. 190, represent two mountain masses of unequal area -and unequal elevation. Let the opposite ends of the snowlines of both -figures lie 1,000 feet apart as between the windward and leeward sides -of a broad cordillera (A), or as between the relatively sunnier and -relatively shadier slopes of individual mountains or narrow ranges in -high latitudes or high altitudes (B). With increasing elevation there is -increasing contrast between temperatures in sunshine and in shade, hence -a greater degree of canting (B). Tending toward a still greater degree -of contrast is the effect of the differences in the amounts of snowy -precipitation, which are always more marked on an isolated and lofty -mountain summit than upon a broad mountain mass (1) because in the -former there is a very restricted area where snow may accumulate, and -(2) because with increase of elevation there is a rapid and differential -decrease in both the rate of adiabatic cooling and the amount of water -vapor; hence the snow-producing forces are more quickly dissipated. - -[Illustration: FIG. 185--Glacial features in the Peruvian Andes near -Arequipa. Sketched from a railway train, July, 1911. The horizontal -broken lines represent the lower limit of light snow during late June, -1911. There is a fine succession of moraines in U-shaped valleys in all -the mountains of the Arequipa region. _A_ represents a part of Chacchani -northwest of Arequipa; _B_ is looking south by east at the northwest end -of Chacchani near Pampa de Arrieros; _C_ also shows the northwest end of -Chacchani from a more distant point.] - -[Illustration: FIG. 186--Canted snowline in the Cordillera Vilcapampa -between Arma and Choquetira. Looking east from 13,500 feet.] - -[Illustration: FIG. 187--Glacial topography between Lambrama and -Antabamba in the Central Ranges. A recent fall of snow covers the -foreground. The glaciers are now almost extinct and their action is -confined to the deepening and steepening of the cirques at the valley -heads.] - -[Illustration: FIG. 188--Asymmetrical peaks in the Central Ranges -between Antabamba and Lambrama. The snow-filled hollows in the -photograph face away from the sun--that is, south--and have retained -snow since the glacial epoch; while the northern slopes are snow-free. -There is no true glacial ice and the continued cirque recession is due -to nivation.] - -[Illustration: FIG. 189--Glacial topography north of the divide on the -seventy-third meridian. Maritime Cordillera. Looking downstream at an -elevation of 16,500 feet (5,030 m.).] - -Furthermore, the leeward side of a lofty mountain not only receives much -less snow proportionally than the leeward side of a lower mountain, -but also loses it faster on account of the smaller extent of surface -upon which it is disposed and the proportionally larger extent of -counteractive, snow-free surface about it. Among the volcanoes of -Ecuador are many that show differences of 500 feet in snowline elevation -on windward and leeward (east) slopes and some, as for example -Chimborazo, that exhibit differences of 1,000 feet. The latter figure -also expresses the differences in the broad Cordillera Vilcapampa and in -the Maritime Cordillera, though the _rate_ of canting as expressed in -degrees is much greater in the case of the western mountains. - -[Illustration: FIG. 190--To illustrate the difference in the degree of -canting of the snowline on large and on small mountain masses.] - -The advantages of the proposed method of indicating the degree of -canting of the snowline lie in the possibility thus afforded of -ultimately separating and expressing quantitatively the various factors -that affect the position of the line. In the Cordillera Vilcapampa, for -example, the dominant canting force is the difference between sun and -shade temperatures, while in the volcanoes of Ecuador, where -_symmetrical volcanoes, almost on the equator, have equal insolation on -all aspects_ and the temperature contrasts are reduced to a minimum--the -differences are owing chiefly to varying exposure to the winds. The -elusive factors in the comparison are related to the differences in area -and in elevation. - -The value of arriving finally at close snowline analyses grows out of -(1) the possibility of snowline changes in short cycles and (2) -uncertainty of arriving by existing methods at the snowline of the -glacial period, whose importance is fundamental in refined physiographic -studies in glaciated regions with a complex topography. To show the -application of the latter point we shall now attempt to determine the -snowline of the glacial period in the belt of country along the route of -the Expedition. - -In the group of peaks shown in Fig. 188 between Lambrama and Antabamba, -the elevation of the snowline varies from 16,000 to 17,000 feet -(4,880-5,180 m.), depending on the topography and the exposure. The -determination of the limit of perpetual snow was here, as elsewhere -along the seventy-third meridian, based upon evidences of nivation. It -will be observed in Fig. 191 that just under the snow banks to the left -of the center are streams of rock waste which head in the snow. Their -size is roughly proportional to the size of the snow banks, and, -furthermore, they are not found on snow-free slopes. From these facts it -is concluded that they represent the waste products of snow erosion or -nivation, just as the hollows in which the snow lies represent the -topographic products of nivation. On account of the seasonal and annual -variation in precipitation and temperature--hence in the elevation of -the snowline--it is often difficult to make a correct snowline -observation based upon depth and _apparent_ permanence. Different -observers report great changes in the snowline in short intervals, -changes not explained by instrumental variations, since they are -referred to topographic features. It appears to be impossible to rely -upon present records for small changes possibly related to minor -climatic cycles because of a lack of standardization of observations. - -Nothing in the world seems simpler at first sight than an observation on -the elevation of the snowline. Yet it can be demonstrated that large -numbers of observers have merely noted the position of temporary snow. -It is strongly urged that evidences of nivation serve henceforth as -proof of permanent snow and that photographic records be kept for -comparison. In this way measurements of changes in the level of the -snowline may be accurately made and the snow cover used as a climatic -gauge. - -Farther west in the Maritime Cordillera, the snowline rises to 18,000 -feet on the northern slopes of the mountains and to 17,000 feet on the -southern slopes. The top of the pass above Cotahuasi, 17,600 feet (5,360 -m.), was snow-free in October, 1911, but the snow extended 500 feet -lower on the southern slope. The degree of canting is extraordinary at -this point, single volcanoes only 1,500 to 2,000 feet above the general -level and with bases but a few miles in circumference exhibit a thousand -feet of difference in the snowline upon northern and southern aspects. -This is to be attributed no less to the extreme elevation of the snow -(and, therefore, stronger contrasts of shade and sun temperatures) than -to the extreme aridity of the region and the high daytime temperatures. -The aridity is a factor, since heavy snowfall means a lengthening of the -period of precipitation in which a cloud cover shuts out the sun and a -shortening of the period of insolation and melting. - -Contrasts between shade and sun temperatures increase with altitude but -their effects also increase in _time_. Of two volcanoes of equal size -and both 20,000 feet above sea level, that one will show the greater -degree of canting that is longer exposed to the sun. The high daytime -temperature is a factor, since it tends to remove the thinnest snow, -which also falls in this case on the side receiving the greatest amount -of heat from the sun. The high daytime temperature is phenomenal in this -region, and is owing to the great extent of snow-free land at high -elevations and yet below the snowline, and to the general absence of -clouds and the thinness of vegetation. - -On approach to the western coast the snowline descends again to 17,500 -feet on Coropuna. There are three chief reasons for this condition. -First, the well-watered Majes Valley is deeply incised almost to the -foot of Coropuna, above Chuquibamba, and gives the daily strong sea -breeze easy access to the mountain. Second, the Coast Range is not only -low at the mouth of the Majes Valley, but also is cut squarely across by -the valley itself, so that heavy fogs and cloud sweep inland nightly and -at times completely cover both valley and desert for an hour after -sunrise. Although these yield no moisture to the desert or the valley -floor except such as is mechanically collected, yet they do increase the -precipitation upon the higher elevations at the valley head. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM DIRECTOR - -ANTABAMBA QUADRANGLE] - -A third factor is the size of Coropuna itself. The mountain is not a -simple volcano but a composite cone with five main summits reaching well -above the snowline, the highest to an elevation of 21,703 feet (6,615 -m.). It measures about 20 miles (32 km.) in circumference at the -snowline and 45 miles (72 km.) at its base (measuring at the foot of the -steeper portion), and stands upon a great tributary lava plateau from -15,000 to 17,000 feet above sea level. Compared with El Misti, at -Arequipa, its volume is three times as great, its height two thousand -feet more, and its access to ocean winds at least thirty per cent more -favorable. El Misti, 19,200 feet (5,855 m.) has snow down as far as -16,000 feet in the wet season and rarely to 14,000 feet, though by -sunset a fall of snow may almost disappear whose lower limit at sunrise -was 16,000 feet. Snow may accumulate several thousand feet below the -summit during the wet season, and in such quantities as to require -almost the whole of the ensuing dry season (March to December) for its -melting. Northward of El Misti is the massive and extended range, -Chachani, 20,000 feet (6,100 m.) high; on the opposite side is the -shorter range called Pichu-Pichu. Snow lies throughout the year on both -these ranges, but in exceptional seasons it nearly disappears from -Chachani and wholly disappears from Pichu-Pichu, so that the snowline -then rises to 20,000 feet. It is considered that the mean of a series of -years would give a value between 17,000 and 18,000 feet for the snowline -on all the great mountains of the Arequipa region.[57] This would, -however, include what is known to be temporary snow; the limit of -"perpetual" snow, or the true snowline, appears to lie about 19,000 feet -on Chachani and _above_ El Misti, say 19,500 feet. It is also above the -crest of Pichu-Pichu. The snowline, therefore, appears to rise a -thousand feet from Coropuna to El Misti, owing chiefly to the poorer -exposure of the latter to the sources of snowy precipitation. - -It may also be noted that the effect of the easy access of the ocean -winds in the Coropuna region is also seen in the increasing amount of -vegetation which appears in the most favorable situations. Thus, along -the Salamanca trail only a few miles from the base of Coropuna are a few -square kilometers of _quenigo_ woodland generally found in the cloud -belt at high altitudes; for example, at 14,000 feet above Lambrama and -at 9,000 feet on the slope below Incahuasi, east of Pasaje. The greater -part of the growth is disposed over hill slopes and on low ridges and -valley walls. It is, therefore, clearly unrelated as a whole to the -greater amount of ground-water with which a part is associated, as along -the valley floors of the streams that head in the belt of perpetual -snow. The appearance of this growth is striking after days of travel -over the barren, clinkery lava plateau to eastward that has a less -favorable exposure. The _quenigo_ forest, so-called, is of the greatest -economic value in a land so desolate as the vast arid and semi-arid -mountain of western Peru. Every passing traveler lays in a stock of -fire-wood as he rests his beasts at noonday; and long journeys are made -to these curious woodlands from both Salamanca and Chuquibamba to gather -fuel for the people of the towns. - - -NIVATION - -The process of nivation, or snow erosion, does not always produce -visible effects. It may be so feeble as to make no impression upon very -resistant rock where the snow-fall is light and the declivity low. -Ablation may in such a case account for almost the whole of the snow -removed. On strong and topographically varied slopes where the snow is -concentrated in headwater alcoves, there is a more pronounced downward -movement of the snow masses with more prominent effects both of erosion -beneath the snow and of accumulation at the border of the snow. In such -cases the limit of perpetual snow may be almost as definitely known as -the limit of a glacier. Like glaciers these more powerful snow masses -change their limits in response to regional changes in precipitation, -temperature, or both. It would at first sight appear impossible to -distinguish between these changes through the results of nivation. Yet -in at least a few cases it may be as readily determined as the past -limits of glaciers are inferred from the terminal moraines, still -intact, that cross the valley floors far below the present limits of the -ice. - -In discussing the process of nivation it is necessary to assume a -sliding movement on the part of the snow, though it is a condition in -Matthes' original problem in which the nivation idea was introduced that -the snow masses remain stationary. It is believed, however, that -Matthes' valuable observations and conclusions really involve but half -the problem of nivation; or at the most but one of two phases of it. He -has adequately shown the manner in which that phase of nivation is -expressed which we find _at the border of the snow_. Of the action -_beneath_ the snow he says merely: "Owing to the frequent oscillations -of the edge and the successive exposure of the different parts of the -site to frost action, the area thus affected will have no well-defined -boundaries. The more accentuated slopes will pass insensibly into the -flatter ones, and the general tendency will be to give the drift site a -cross section of smoothly curved outline and ordinarily concave."[58] - -From observations on the effects of nivation in valleys, Matthes further -concludes that "on a grade of about 12 per cent ... névé must attain a -thickness of at least 125 feet in order that it may have motion,"[59] -though as a result of the different line of observations Hobbs -concludes[60] that a somewhat greater thickness is required. - -[Illustration: FIG. 191--The "pocked" surface characteristically -developed in the zone of light nivation. Compare with Fig. 194, showing -the effects of heavy nivation.] - -[Illustration: FIG. 192--Steep cirque walls and valleys head in the -Central Ranges between Lambrama and Chuquibambilla. The snow is here a -vigorous agent in transporting talus material and soil from all the -upper slopes down to the foot of the cirque wall.] - -The snow cover in tropical mountains offers a number of solid advantages -in this connection. Its limits, especially on the Cordillera Vilcapampa, -on the eastern border of the Andes, are subject to _small seasonal -oscillations_ and the edge of the "perpetual" snow is easily determined. -Furthermore, it is known from the comparatively "fixed quality of -tropical climate," as Humboldt put it, that the variations of the -snowline in a period of years do not exceed rather narrow limits. In -mid-latitudes on the contrary there is an extraordinary shifting of the -margin of the snow cover, and a correspondingly wide distribution of -the feeble effects of nivation. - -[Illustration: FIG. 193--Panta Mountain and its glacier system. The -talus-covered mass in the center (B) is a terminal moraine topped by the -dirt-stained glacier that descends from the crest. The separate glaciers -were formerly united to form a huge ice tongue that truncated the -lateral spurs and flattened the valley floor. One of its former stages -is shown by the terminal moraine in the middle distance, breached by a -stream, and impounding a lake not visible from this point of view.] - -[Illustration: FIG. 194--Recessed southern slopes of volcanoes whose -northern slopes are practically without glacial modifications. Summit of -the lava plateau, Maritime Cordillera, western Peru, between Antabamba -and Cotahuasi.] - -Test cases are presented in Figs. 191, 192, and 193, Cordillera -Vilcapampa, for the determination of the fact of the movement of the -snow long before it has reached the thickness Matthes or Hobbs believes -necessary for a movement of translation to begin. Fig. 191 shows snow -masses occupying pockets on the slope of a ridge that was never covered -with ice. Past glacial action with its complicating effects is, -therefore, excluded and we have to deal with snow action pure and -simple. The pre-glacial surface with smoothly contoured slopes is -recessed in a noteworthy way from the ridge crest to the snowline of the -glacial period at least a thousand feet lower. The recesses of the -figure are peculiar in that not even the largest of them involve the -entire surface from top to bottom; they are of small size and are -scattered over the entire slope. This is believed to be due to the fact -that they represent the limits of variations of the snowline in short -cycles. Below them as far as the snowline of the glacial period are -larger recesses, some of which are terminated by masses of waste as -extensive as the neighboring moraines, but disposed in irregular -scallops along the borders of the ridges or mountain slopes in which the -recesses have been found. - -The material accumulated at the lower limit of the snow cover of the -glacial period was derived from two sources: (1) from slopes and cliffs -overlooking the snow, (2) from beneath the snow by a process akin to ice -plucking and abrasion. The first process is well known and resembles the -shedding of waste upon a valley glacier or a névé field from the -bordering cliffs and slopes. Material derived in this manner in many -places rolls down a long incline of snow and comes to rest at the foot -of it as a fringe of talus. The snow is in this case but a substitute -for a normal mass of talus. The second process produces its most clearly -recognizable effects on slopes exceeding a declivity of 20°; and upon -30° and 40° slopes its action is as well-defined as true glacial action -which it imitates. It appears to operate in its simplest form as if -independent of the mass of the snow, small and large snow patches -showing essentially the same results. This is the reverse of Matthes' -conclusion, since he says that though the minimum thickness "must vary -inversely with the percentage of the grade," "the influence of the grade -is inconsiderable," and that the law of variation must depend upon -additional observation.[61] - -Let us examine a number of details and the argument based upon them and -see if it is not possible to frame a satisfactory law of variation. - -In Fig. 193 the chief conditions of the problem are set forth. Forward -from the right-hand peak are snow masses descending to the head of a -talus (_A_) whose outlines are clearly defined by freshly fallen snow. -At (_B_) is a glacier whose tributaries descend the middle and left -slopes of the picture after making a descent from slopes several -thousand feet higher and not visible in this view. The line beneath the -glacier marks the top of the moraine it has built up. Moraines farther -down valley show a former greater extent of the glacier. Clearly the -talus material at (_A_) was accumulated after the ice had retreated to -its present position. It will be readily seen from an inspection of the -photograph that the total amount of material at (_A_) is an appreciable -fraction of that in the moraine. The ratio appears to be about 1:8 or -1:10. I have estimated that the total area of snow-free surface about -the snowfields of the one is to that of the other as 2:3. The gradients -are roughly equivalent, but the volume of snow in the one case is but a -small fraction of that in the other. It will be seen that the snow -masses have recessed the mountain slopes at _A_ and formed deep hollows -and that the hollowing action appears to be most effective where the -snow is thickest. - -Summarizing, we note first, that the roughly equivalent factors are -gradient and amount of snow-free surface; second, that the unequal -factors are (a) accumulated waste, (b) degree of recessing, and (c) the -degree of compacting of snow into ice and a corresponding difference in -the character of the glacial agent, and (d) the extent of the snow -cover. The direct and important relation of the first two unequal -factors to the third scarcely need be pointed out. - -We have then an inequality in amount of accumulated material to be -explained by either an inequality in the extent of the snow and -therefore an inequality of snow action, or an inequality due to the -presence of ice in one valley and not in the other, or by both. It is at -once clear that if ice is absent above (_A_) and the mountain slopes are -recessed that snow action is responsible for it. It is also recognized -that whatever rate of denudation be assigned to the snow-free surfaces -this rate must be exceeded by the rate of snow action, else the -inequalities of slope would be decreased rather than increased. The -accumulated material at (_A_) is, therefore, partly but not chiefly due -to denudation of snow-free surfaces. It is due chiefly to _erosion_ -beneath the snow. Nor can it be argued that the hollows now occupied by -snow were formed at some past time when ice not snow lay in them. They -are not ice-made hollows for they are on a steep spur above the limits -of ice action even in the glacial period. Any past action is, therefore, -represented here in _kind_ by present action, though there would be -differences in _degree_ because the heavier snows of the past were -displaced by the lighter snows of today. - -While it appears that the case presents clear proof of degradation by -snow it is not so clear how these results were accomplished. Real -abrasion on a large scale as in bowlder-shod glaciers is ruled out, -since glacial striæ are wholly absent from nivated surfaces according to -both Matthes' observations and my own. Yet all nivated surfaces have -very distinctive qualities, delicately organized slopes which show a -marked change from any original condition related to water-carving. In -the absence of striæ, the general absence of all but a thin coating of -waste _even in rock hollows_, and the accumulation of waste up to -bowlders in size at the lower edge of the nivated zone, I conclude that -compacted snow or névé of sufficient thickness and gradient may actually -pluck rock outcrops in the same manner though not at the rate which ice -exhibits. That the products of nivation may be bowlders as well as fine -mud would seem clearly to follow increase in effectiveness, due to -increase in amount of the accumulated snow; that bowlders are actually -transported by snow is also shown by their presence on the lower margins -of nivated tracts. - -Our argument may be made clearer by reference to the observed action of -snow in a particular valley. Snow is shed from the higher, steeper -slopes to the lower slopes and eventually accumulates to a marked degree -on the bottoms of the depressions, whence it is avalanched down valley -over a series of irregular steps on the valley floor. An avalanche takes -place through the breaking of a section of snow just as an iceberg -breaks off the end of a tide-water glacier. Evidently there must be -pressure from behind which crowds the snow forward and precipitates it -to a lower level. - -As a snow mass falls it not only becomes more consolidated, beginning at -the plane of impact, but also gives a shock to the mass upon which it -falls that either starts it in motion or accelerates its rate of motion. -The action must therefore be accompanied by a drag upon the floor and if -the rock be close-jointed and the blocks, defined by the joint planes, -small enough, they will be transported. Since snow is not so compact as -ice and permits included blocks easily to adjust themselves to new -resistances, we should expect the detached blocks included in the snow -to change their position constantly and to form irregular scratches, but -not parallel striæ of the sort confidently attributed to stone-shod ice. - -It is to the plasticity of snow that we may look for an explanation of -the smooth-contoured appearance of the landscape in the foreground of -Fig. 135. The smoothly curved lines are best developed where the entire -surface was covered with snow, as in mid-elevations in the larger -snowfields. At higher elevations, where the relief is sharper, the snow -is shed from the steeper declivities and collected in the minor basins -and valley heads, where its action tends to smooth a floor of limited -area, while snow-free surfaces retain all their original irregularities -of form or are actually sharpened. - -The degree of effectiveness of snow and névé action may be estimated -from the reversed slopes now marked by ponds or small marshy tracts -scattered throughout the former névé fields, and the many niched -hollows. They are developed above Pampaconas in an admirable manner, -though their most perfect and general development is in the summit belt -of the Cordillera Vilcapampa between Arma and Choquetira, Fig. 135. It -is notable in _all_ cases where nivation was associated with the work of -valley glaciers that the rounded nivated slopes break rather sharply -with the steep slopes that define an inner valley, whose form takes on -the flat floor and under-cut marginal walls normal to valley glaciation. - -A classification of numerous observations in the Cordillera Vilcapampa -and in the Maritime Cordillera between Lambrama and Antabamba may now be -presented as the basis for a tentative expression of the law of -variation respecting snow motion. The statement of the law should be -prefaced by the remark that thorough checking is required under a wider -range of conditions before we accept the law as final. Near the lower -border of the snow where rain and hail and alternate freezing and -thawing take place, the snow is compacted even though but fifteen to -twenty feet thick, and appears to have a down-grade movement and to -exercise a slight drag upon its floor when the gradient does not fall -below 20°. Distinct evidences of nivation were observed on slopes with a -declivity of 5° near summit areas of past glacial action, where the snow -did not have an opportunity to be alternately frozen and thawed. - -The _thickness_ of the former snow cover could, however, not be -accurately determined, but was estimated from the topographic -surroundings to have been at least several hundred feet. Upon a 40° -slope a snow mass 50 feet thick was observed to be breaking off at a -cliff-face along the entire cross-section as if impelled forward by -thrust, and to be carrying a small amount of waste--enough distinctly to -discolor the lowermost layers--which was shed upon the snowy masses -below. With increase in the degree of compactness of the snow at -successively lower elevations along a line of snow discharge, gradients -down to 25° were still observed to carry strongly crevassed, waste-laden -snow down to the melting border. It appeared from the clear evidences of -vigorous action--the accumulation of waste, the strong crevassing, the -stream-like character of the discharging snow, and the pronounced -topographic depression in which it lay--that much flatter gradients -would serve, possibly not more than 15°, for a snow mass 150 feet wide, -30 to 40 feet thick, and serving as the outlet for a set of tributary -slopes about a square mile in area and with declivities ranging from -small precipices to slopes of 30°. - -We may say, therefore, that the factors affecting the rate of motion are -(1) thickness, (2) degree of compactness, (3) diurnal temperature -changes, and (4) gradient. Among these, diurnal temperature changes -operate indirectly by making the snow more compact and also by inducing -motion directly. At higher elevations above the snowline, temperature -changes play a decreasingly important part. The thickness required -varies inversely as the gradient, and upon a 20° slope is 20 feet for -wet and compact snow subjected to alternate freezing and thawing. For -dry snow masses above the zone of effective diurnal temperature changes, -an increasing gradient is required. With a gradient of 40°, less than 50 -feet of snow will move _en masse_ if moderately compacted under its own -weight; if further compacted by impact of falling masses from above, the -required thickness may diminish to 40 feet and the required declivity to -15°. The gradient may decrease to 0° or actually be reversed and motion -still continue provided the compacting snow approach true névé or even -glacier ice as a limit. - -From the sharp topographic break between the truly glaciated portions of -the valley in regions subjected to temporary glaciation, it is concluded -that the eroding power of the moving mass is suddenly increased at the -point where névé is finally transformed into true ice. This -transformation must be assumed to take place suddenly to account for so -sudden a change of function as the topographic break requires. Below the -point at which the transformation occurs the motion takes place under a -new set of conditions whose laws have already been formulated by -students of glaciology. - -[Illustration: FIG. 195--Curve of snow motion. Based on many -observations of snow motion to show minimum thickness of snow required -to move on a given gradient. Figures on the left represent thickness of -snow in feet. The degrees represent the gradient of the surface. The -gradients have been run in sequence down to 0° for the sake of -completing the accompanying discussion. Obviously no glacially -unmodified valley in a region of mountainous relief would start with so -low a gradient, though glacial action would soon bring it into -existence. Between +5° and -5° the curve is based on the gradients of -nivated surfaces.] - -The foregoing readings of gradient and depth of snow are typical of a -large number which were made in the Peruvian Andes and which have served -as the basis of Fig. 195. It will be observed that between 15° and 20° -there is a marked change of function and again between +5° and -5° -declivity, giving a double reversed curve. The meaning of the change -between 15° and 20° is inferred to be that, with gradients over 20°, -snow cannot wholly resist gravity in the presence of diurnal temperature -changes across the freezing point and occasional snow or hail storms. -With increase of thickness compacting appears to progress so rapidly as -to permit the transfer of thrust for short distances before absorption -of thrust takes place in the displaced snow. At 250 feet thorough -compacting appears to take place, enabling the snow to move out under -its own weight on even the faintest slopes; while, with a thickness -still greater, the resulting névé may actually be forced up slight -inclines whose declivity appears to approach 5° as a limit. I have -nowhere been able to find in truly nivated areas reversed curves -exceeding 5°, though it should be added that depressions whose leeward -slopes were reversed to 2° and 3° are fairly common. If the curve were -continued we should undoubtedly find it again turning to the left at the -point where the thickness of the snow results in the transformation of -snow to ice. From the sharp topographic break observed to occur in a -narrow belt between the névé and the ice, it is inferred that the -erosive power of the névé is to that of the ice as 2:4 or 1:5 _for equal -areas_; and that reversed slopes of a declivity of 10° to 15° may be -formed by glaciers is well known. Precisely what thickness of snow or -névé is necessary and what physical conditions effect its transformation -into ice are problems not included in the main theme of this chapter. - -It is important that the proposed curve of snow motion under minimum -conditions be tested under a large variety of circumstances. It may -possibly be found that each climatic region requires its special -modifications. In tropical mountains the sudden alternations of freezing -and thawing may effect such a high degree of compactness in the snow -that lower minimum gradients are required than in the case of -mid-latitude mountains where the perpetual snow of the high and cold -situations is compacted through its own weight. Observations of the -character introduced here are still unattainable, however. It is hoped -that they will rapidly increase as their significance becomes apparent; -and that they have high significance the striking nature of the curve of -motion seems clearly to establish. - - -BERGSCHRUNDS AND CIRQUES - -The facts brought out by the curve of snow-motion (Fig. 195) have an -immediate bearing on the development of cirques, whose precise mode of -origin and development have long been in doubt. Without reviewing the -arguments upon which the various hypotheses rest, we shall begin at once -with the strongest explanation--W. D. Johnson's famous bergschrund -hypothesis. The critical condition of this hypothesis is the diurnal -migration across the freezing point of the air temperature at the bottom -of the schrund. Alternate freezing and thawing of the water in the -joints of the rock to which the schrund leads, exercise a quarrying -effect upon the rock and, since this effect is assumed to take place at -the foot of the cirque, the result is a steady retreat of the steep -cirque wall through basal sapping. - -While Johnson's hypothesis has gained wide acceptance and is by many -regarded as the final solution of the cirque problem it has several -weaknesses in its present form. In fact, I believe it is but one of two -factors of equal importance. In the first place, as A. C. Andrews[62] -has pointed out, it is extremely improbable that the bergschrund of -glacial times under the conditions of a greater volume of snow could -have penetrated to bedrock at the base of the cirque where the present -change of slope takes place. In the second place, the assumption is -untenable that the bergschrund in all cases reaches to or anywhere near -the foot of the cirque wall. A third condition outside the hypothesis -and contradictory to it is the absence of a bergschrund in snowfields at -many valleys heads where cirques are well developed! - -Johnson himself called attention to the slender basis of observation -upon which his conclusions rest. In spite of his own caution with -respect to the use of his meager data, his hypothesis has been applied -in an entirely too confident manner to all kinds of cirques under all -kinds of conditions. Though Johnson descended an open bergschrund to a -rock floor upon which ice rested, his observations raise a number of -proper questions as to the application of these valuable data: How long -are bergschrunds open? How often are they open? Do they everywhere open -to the foot of the cirque wall? Are they present for even a part of the -year in all well-developed cirques? Let us suppose that it is possible -to find many cirques filled with snow, not ice, surrounded by truly -precipitous walls and with an absence of bergschrunds, how shall we -explain the topographic depressions excavated underneath the snow? If -cirque formation can be shown to take place without concentrated frost -action at the foot of the bergschrund, then is the bergschrund not a -secondary rather than a primary factor? And must we not further conclude -that when present it but hastens an action which is common to all -snow-covered recesses? - -It is a pleasure to say that we may soon have a restatement of the -cirque problem from the father of the bergschrund idea. The argument in -this chapter was presented orally to him after he had remarked that he -was glad to know that some one was finding fault with his hypothesis. -"For," he said, with admirable spirit, "I am about to make a most -violent attack upon the so-called Johnson hypothesis." I wish to say -frankly that while he regards the following argument as a valid addition -to the problem, he does not think that it solves the problem. There are -many of us who will read his new explanation with the deepest interest. - -[Illustration: FIG. 196--Relation of cirque wall to trough's end at the -head of a glaciated valley. The ratio of the inner to the outer radius -is 1:4.] - -[Illustration: FIG. 197--Mode of cirque formation. Taking the facts of -snow depth represented in the curve, Fig. 195, and transposing them over -a profile (the heavy line) which ranges from 0° declivity to 50°, we -find that the greatest excess of snow occurs roughly in the center. Here -ice will first form at the bottom of the snow in the advancing hemicycle -of glaciation, and here it will linger longest in the hemicycle of -retreat. Here also there will be the greatest mass of névé. All of these -factors are self-stimulating and will increase in time until the floor -of the cirque is flattened or depressed sufficiently to offset through -uphill ice-flow the augmented forces of erosion. The effects of -self-stimulation are shown by "snow increase"; the ice shoe at the -bottom of the cirque is expressed by "ice factor." The form accompanying -both these terms is merely suggestive. The top of "excess snow" has a -gradient characteristic of the surface of snow fields. A preglacial -gradient of 0° is not permissible, but I have introduced it to complete -the discussion in the text and to illustrate the flat floor of a cirque. -A bergschrund is not required for any stage of this process, though the -process is hastened wherever bergschrunds exist.] - -We shall begin with the familiar fact that many valleys, now without -perpetual snow, formerly contained glaciers from 500 to 1,000 feet thick -and that their snowfields were of wide extent and great depth. At the -head of a given valley where the snow is crowded into a small -cross-section it is compacted and suffers a reduction in its volume. At -first nine times the volume of ice, the gradually compacting névé -approaches the volume of ice as a limit. At the foot of the cirque wall -we may fairly assume in the absence of direct observations, a volume -reduction of one-half due to compacting. But this is offset in the case -of a well-developed cirque by volume increases due to the convergence of -the snow from the surrounding slopes, as shown in Fig. 196. Taking a -typical cirque from a point above Vilcabamba pueblo I find that the -radius of the trough's end is to the radius of the upper wall of the -cirque as 1:4; and since the corresponding surfaces are to one another -as the squares of their similar dimensions we have 1:4 or 1:16 as the -ratio of their snow areas. If no compacting took place, then to -accommodate all the snow in the glacial trough would require an increase -in thickness in the ratio of 1:4. If the snow were compacted to half its -original volume then the ratio would be 1:2. Now, since the volume ratio -of ice to snow is 1:9 and the thickness of the ice down valley is, say -400 feet, the equivalent of loose snow at the foot of the cirque must be -more than 1:4 over 1:9 or more than two and one-quarter times thicker, -or 400 feet thick; and would give a pressure of (900 ÷ 10) × 62.5 -pounds, or 5,625 pounds, or a little less than three tons per square -foot. Since a pressure of 2,500 pounds per square foot will convert snow -into ice at freezing temperature, it is clear that ice and not snow was -the state at the bottom of the mass in glacial times. Further, between -the surface of the snow and the surface of the bottom layer of the ice -there must have been every gradation between loose snow and firm ice, -with the result that a thickness much less than 900 feet must be -assumed. Precisely what thickness would be found at the foot of the -cirque wall is unknown. But granting a thickness of 400 feet of ice an -additional 300 feet for névé and snow would raise the total to 700 feet. - -The application of the facts in the above paragraph is clearly seen when -we refer to Fig. 197. The curve of snow motion of Fig. 195 is applied to -an unglaciated mountain valley. Taking a normal snow surface and filling -the valley head it is seen that the excess of snow depth over the amount -required to give motion is a measure at various points in the valley -head and at different gradients of the erosive force of the snow. It is -strikingly concentrated on the 15°-20° gradient which is precisely where -the so-called process of basal sapping is most marked. If long continued -the process will lead to the developing of a typical cirque for it is a -process that is self-stimulating. The more the valley is changed in form -the more it tends to change still further in form because of deepening -snowfields until cliffed pinnacles and matterhorns result. - -By further reference to the figure it is clear that a schrund 350 feet -deep could not exist on a cirque wall with a declivity of even 20° -without being closed by flow, unless we grant _more rapid flow_ below -the crevasse. In the case of a glacier flowing over a nearly flat bed -away from the cirque it is difficult to conceive of a rate of flow -greater than that of snow and névé on the steep lower portion of the -cirque wall, when movement on that gradient _begins_ with snow but 20 -feet thick. - -In contrast to this is the view that the schrund line should lie well up -the cirque wall where the snow is comparatively thin and where there is -an approach to the lower limits of movement. The schrund would appear to -open where the bottom material changes its form, i.e., where it first -has its motion accelerated by transformation into névé. In this view -the schrund opens not at the foot of the cirque wall but well above it -as in Fig. 198, in which _C_ represents snow from top to bottom; _B_, -névé; and _A_, ice. The required conditions are then (1) that the -steepening of the cirque wall from _x_ to _y_ should be effected by -sapping originated at _y_ through the agencies outlined by Johnson; (2) -that the steepening from _x_ to _y_ should be effected by sapping -originated at _x_ through the change of the agent from névé to ice with -a sudden change of function; (3) and that the essential unity of the -wall _x-y-z_ be maintained through the erosive power of the névé, which -would tend to offset the formation of a shelf along a horizontal plane -passed through _y_. The last-named process not only appears entirely -reasonable from the conditions of gradient and depth outlined on pp. 296 -to 298, but also meets the actual field conditions in all the cases -examined in the Peruvian Andes. This brings up the second and third of -our main considerations, that the bergschrund does not always or even in -many cases reach the foot of the cirque wall, and that cirques exist in -many cases where bergschrunds are totally absent. - -It is a striking fact that frost action at the bottom of the bergschrund -has been assumed to be the only effective sapping force, in spite of the -common observation that bergschrunds lie in general well toward the -upper limits of snowfields--so far, in fact, that their bottoms in -general occur several hundred feet above the cirque floors. Is the -cirque under these circumstances a result of the schrund or is the -schrund a result of the cirque? _In what class of cirques do schrunds -develop?_ If cirque development in its early stages is not marked by the -development of bergschrunds, then are bergschrunds an _essential_ -feature of cirques in their later stages, however much the sapping -process may be hastened by schrund formation? - -Our questions are answered at once by the indisputable facts that many -schrunds occur well toward the upper limit of snow, and that many -cirques exist whose snowfields are not at all broken by schrunds. It was -with great surprise that I first noted the bergschrunds of the Central -Andes, especially after becoming familiar with Johnson's apparently -complete proof of their genetic relation to the cirques. But it was less -surprising to discover the position of the few observed--high up on the -cirque walls and always near the upper limit of the snowfields. - -A third fact from regions once glaciated but now snow-free also combined -with the two preceding facts in weakening the wholesale application of -Johnson's hypothesis. In many headwater basins the cirque whose wall at -a distance seemed a unit was really broken into two unequal portions; a -lower, much grooved and rounded portion and an upper unglaciated, -steep-walled portion. This condition was most puzzling in view of the -accepted explanation of cirque formation, and it was not until the two -first-named facts and the applications of the curves of snow motion were -noted that the meaning of the break on the cirque became clear. -Referring to Fig. 198 we see at once that the break occurs at _y_ and -means that under favorable topographic and geologic conditions sapping -at _y_ takes place faster than at _x_ and that the retreat of _y-z_ is -faster than _x-y_. It will be clear that when these conditions are -reversed or sapping at _x_ and at _y_ are equal a single wall will -result. On reference to the literature I find that Gilbert recently -noted this feature and called it the _schrundline_.[63] He believes that -it marks the base of the bergschrund _at a late stage in the excavation -of the cirque basin_. He notes further that the lower less-steep slope -is glacially scoured and that it forms "a sort of shoulder or terrace." - -[Illustration: FIG. 198--The development of cirques. See text, p. 209, -and Fig. 199.] - -If all the structural and topographic conditions were known in a great -variety of gathering basins we should undoubtedly find in them, and not -in special forms of ice erosion, an explanation of the various forms -assumed by cirques. The limitations inherent in a high-altitude field -and a limited snow cover prevented me from solving the problem, but it -offered sufficient evidence at least to indicate the probable lines of -approach to a solution. For example it is noteworthy that in _all_ the -cases examined the schrundline was better developed the further glacial -erosion had advanced. So constantly did this generalization check up, -that if at a distance a short valley was observed to end in a cirque, I -knew at once and long before I came to the valley head that a shoulder -below the schrundline did not exist. At the time this observation was -made its significance was a mystery, but it represents a condition so -constant that it forms one of the striking features of the glacial forms -in the headwater region. - -[Illustration: FIG. 199--Further stages in the development of cirques. -See p. 299 and Fig. 198.] - -The meaning of this feature is represented in Fig. 199, in which three -successive stages in cirque development are shown. In _A_, as displayed -in small valleys or mountainside alcoves which were but temporarily -occupied by snow and ice, or as in all higher valleys during the earlier -stages of the advancing hemicycle of glaciation, snow collects, a short -glacier forms, and a bergschrund develops. As a result of the -concentrated frost action at the base of the bergschrund a rapid -deepening and steepening takes place at _a_. As long as the depth of -snow (or snow and névé) is slight the bergschrund may remain open. But -its existence at this particular point is endangered as the cirque -grows, since the increasing steepness of the slope results in more rapid -snow movement. Greater depth of snow goes hand in hand with increasing -steepness and thus favors the formation of névé and even ice at the -bottom of the moving mass and a constantly accelerated rate of motion. -At the same time the bergschrund should appear higher up for an -independent reason, namely, that it tends to form between a mass of -slight movement and one of greater movement, which change of function, -as already pointed out, would appear to be controlled by change from -snow to névé or ice on the part of the bottom material. - -The first stages in the upward migration of the bergschrund will not -effect a marked change from the original profile, since the converging -slopes, the great thickness of névé and ice at this point, and the steep -gradient all favor powerful erosion. When, however, stage _C_ is -reached, and the bergschrund has retreated to _c"_, a broader terrace -results below the schrundline, the gradient is decreased, the ice and -névé (since they represent a constant discharge) are spread over a -greater area, hence are thinner, and we have the cirque taking on a -compound character with a lower, less steep and an upper, precipitous -section. - -It is clear that a closely jointed and fragile rock might be quarried by -moving ice at _c'-c"_ and the cirque wall extended unbroken to _x_; it -is equally clear that a homogeneous, unjointed granite would offer no -opportunities for glacial plucking and would powerfully resist the much -slower process of abrasion. Thus Gilbert[64] observed the schrundline in -the granites of the Sierra Nevada, which are "in large part -structureless" and my own observations show the schrundline well -developed in the open-jointed granites of the Cordillera Vilcapampa and -wholly absent in the volcanoes of the Maritime Cordillera, where ashes -and cinders, the late products of volcanic action, form the easily -eroded walls of the steep cones. Somewhere between these extremes--lack -of a variety of observations prevents our saying where--the resistance -and the internal structure of the rock will just permit a cirque wall to -extend from _x_ to _c' "_ of Fig. 199. - -A common feature of cirques that finds an explanation in the proposed -hypothesis is the notch that commonly occurs at some point where a -convergence of slopes above the main cirque wall concentrates snow -discharge. It is proposed to call this type the notched cirque. It is -highly significant that these notches are commonly marked by even -steeper descents at the point of discharge into the main cirque than the -remaining portion of the cirque wall, even when the discharge was from a -very small basin and in the form of snow or at the most névé. The excess -of discharge at a point on the basin rim ought to produce the form we -find there under the conditions of snow motion outlined in earlier -paragraphs. It is also noteworthy that it is at such a point of -concentrated discharge that crevasses no sooner open than they are -closed by the advancing snow masses. To my mind the whole action is -eminently representative of the action taking place elsewhere along the -cirque wall on a smaller scale. - -What seems a good test of the explanation of cirques here proposed was -made in those localities in the Maritime Cordillera, where large -snowbanks but not glaciers affect the form of the catchment basins. A -typical case is shown in Fig. 201. As in many other cases we have here a -great lava plateau broken frequently by volcanic cones of variable -composition. Some are of lava, others consist of ashes, still others of -tuff and lava and ashes. At lower elevations on the east, as at 16,000 -feet between Antabamba and Huancarama, evidences of long and powerful -glaciers are both numerous and convincing. But as we rise still higher -the glaciated topography is buried progressively deeper under the -varying products of volcanic action, until finally at the summit of the -lava fields all evidences of glaciation disappear in the greater part of -the country between Huancarama and the main divide. Nevertheless, the -summit forms are in many cases as significantly altered as if they had -been molded by ice. Precipitous cirque walls surround a snow-filled -amphitheater, and the process of deepening goes forward under one's -eyes. No moraines block the basin outlets, no U-shaped valleys lead -forward from them. We have here to do with post-glacial action pure and -simple, the volcanoes having been formed since the close of the -Pleistocene. - -Likewise in the pass on the main divide, the perpetual snow has begun -the recessing of the very recent volcanoes bordering the pass. The -products of snow action, muds and sands up to very coarse gravel, -glaciated in texture with an intermingling of blocks up to six inches in -diameter in the steeper places, are collected into considerable masses -at the snowline, where they form broad sheets of waste so boggy as to be -impassable except by carefully selected routes. No ice action whatever -is visible below the snowline and the snow itself, though wet and -compact, is not underlain by ice. Yet the process of hollowing goes -forward visibly and in time will produce serrate forms. In neither case -is there the faintest sign of a bergschrund; the gradients seem so well -adjusted to the thickness and rate of movement of the snow from point to -point that the marginal crack found in many snowfields is absent. - -The absence of bergschrunds is also noteworthy in many localities where -formerly glaciation took place. This is notoriously the case in the -summit zone of the Cordillera Vilcapampa, where the accumulating snows -of the steep cirque walls tumble down hundreds of feet to gather into -prodigious snowbanks or to form névé fields or glaciers. From the -converging walls the snowfalls keep up an intermittent bombardment of -the lower central snow masses. It is safe to say that if by magic a -bergschrund could be opened on the instant, it would be closed almost -immediately by the impetus supplied by the falling snow masses. The -explanation appears to be that the thicker snow and névé concentrated at -the bottom of the cirque results in a corresponding concentration of -action and effect; and cirque development goes on without reference to a -bergschrund. The chief attraction of the bergschrund hypothesis lies in -the concentration of action at the foot of the cirque wall. But in the -thickening of the snow far beyond the minimum thickness required for -motion at the base of the cirque wall and its change of function with -transformation into névé, we need invoke no other agent. If a -bergschrund forms, its action may take place at the foot of the cirque -wall or high up on the wall, and yet _sapping at the foot of the wall_ -continue. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM DIRECTOR - -LAMBRAMA QUADRANGLE] - -From which we conclude (1) that where frost action occurs at the bottom -of a bergschrund opening to the foot of the cirque wall it aids in the -retreat of the wall; (2) that a sapping action takes place at this point -whether or not a bergschrund exists and that bergschrund action is not a -_necessary_ part of cirque formation; (3) that when a more or less -persistent bergschrund opens on the cirque wall above its foot it tends -to develop a schrundline with a marked terrace below it; (4) that -schrundlines are best developed in the mature stages of topographic -development in the glacial cycle; (5) that the varying rates of snow, -névé, and ice motion at a valley head are the _persistent_ features to -which we must look for topographic variations; (6) that the hypothesis -here proposed is applicable to all cases whether they involve the -presence of snow or névé or ice or any combination of these, and whether -bergschrunds are present or not; and (7) at the same time affords a -reasonable explanation for such variations in forms as the compound -cirque with its schrundline and terrace, the unbroken cirque wall, the -notched cirque, and the recessed, snow-covered mountain slopes -unaffected by ice. - - -ASYMMETRICAL CREST LINES AND ABNORMAL VALLEY PROFILES IN THE CENTRAL -ANDES - -To prove that under similar conditions glacial erosion may be greater -than subaërial denudation quantitative terms must be sought. Only these -will carry conviction to the minds of many opponents of the theory that -ice is a vigorous agent of erosion. Gilbert first showed in the Sierra -Nevada that headwater glaciers eroded more rapidly than nonglacial -agents under comparable topographic and structural conditions.[65] Oddly -enough none of the supporters of opposing theories have replied to his -arguments; instead they have sought evidence from other regions to show -that ice cannot erode rock to an important degree. In this chapter -evidence from the Central Andes, obtained in 1907 and 1911, will be -given to show the correctness of Gilbert's proposition. - -The data will be more easily understood if Gilbert's argument is first -outlined. On the lower slopes of the glaciated Sierra Nevada asymmetry -of form resulted from the presence of ice on one side of each ridge and -its absence on the other (Fig. 200). The glaciers of these lower ridges -were the feeblest in the entire region and were formed on slopes of -small extent; they were also short-lived, since they could have existed -only when glacial conditions had reached a maximum. Let the broken line -in the upper part of the figure represent the preglacial surface and -the solid line beneath it the present surface. It will not matter what -value we give the space between the two lines on the left to express -nonglacial erosion, since had there been no glaciers it would be the -same on both sides of the ridge. The feeble glacier occupying the -right-hand slope was able in a very brief period to erode a depression -far deeper than the normal agents of denudation were able to erode in a -much longer period, i.e., during all of interglacial and postglacial -time. Gilbert concludes: "The visible ice-made hollows, therefore, -represent the local excess of glacial over nonglacial conditions." - -[Illustration: FIG. 200--Diagrammatic cross-section of a ridge glaciated -on one side only; with hypothetical profile (broken line) of preglacial -surface.] - -[Illustration: FIG. 201--Postglacial volcano recessed on shady southern -side by the process of nivation. Absolute elevation 18,000 feet (5,490 -m.), latitude 14° S., Maritime Cordillera, Peru.] - -In the Central Andes are many volcanic peaks and ridges formed since the -last glacial epoch and upon them a remarkable asymmetry has been -developed. Looking southward one may see a smoothly curved, snow-free, -northward-facing slope rising to a crest line which appears as regular -as the slope leading to it. Looking northward one may see by contrast -(Fig. 194) sharp ridges, whose lower crests are serrate, separated by -deeply recessed, snow-filled mountain hollows. Below this highly -dissected zone the slopes are smooth. The smooth slope represents the -work of water; the irregular slopes are the work of snow and ice. The -relation of the north and south slopes is diagrammatically shown in Fig. -201. - -To demonstrate the erosive effects of snow and ice it must be shown: (1) -that the initial slopes of the volcanoes are of postglacial age; (2) -that the asymmetry is not structural; (3) that the snow-free slopes have -not had special protection, as through a more abundant plant cover, more -favorable soil texture, or otherwise. - -Proof of the postglacial origin of the volcanoes studied in this -connection is afforded: (1) by the relation of the flows and the ash and -cinder beds about the bases of the cones to the glacial topography; (2) -by the complete absence of glacial phenomena below the present snowline. -Ascending a marginal valley (Fig. 202), one comes to its head, where two -tributaries, with hanging relations to the main valley, come down from a -maze of lesser valleys and irregular slopes. Glacial features of a -familiar sort are everywhere in evidence until we come to the valley -heads. Cirques, reversed grades, lakes, and striæ are on every hand. But -at altitudes above 17,200 feet, recent volcanic deposits have over large -areas entirely obscured the older glacial topography. The glacier which -occupied the valley of Fig. 202 was more than one-quarter of a mile -wide, the visible portion of its valley is now over six miles long, but -the extreme head of its left-hand tributary is so concealed by volcanic -material that the original length of the glacier cannot be determined. -It was at least ten miles long. From this point southward to the border -of the Maritime Cordillera no evidence of past glaciation was observed, -save at Solimana and Coropuna, where slight changes in the positions of -the glaciers have resulted in the development of terminal moraines a -little below the present limits of the ice. - -From the wide distribution of glacial features along the northeastern -border of the Maritime Cordillera and the general absence of such -features in the higher country farther south, it is concluded that the -last stages of volcanic activity were completed in postglacial time. It -is equally certain, however, that the earlier and greater part of the -volcanic material was ejected before glaciation set in, as shown by the -great depth of the canyons (over 5,000 feet) cut into the lava flows, as -contrasted with the relatively slight filling of coarse material which -was accumulated on their floors in the glacial period and is now in -process of dissection. Physiographic studies throughout the Central -Andes demonstrate both the general distribution of this fill and its -glacial origin. - -So recent are some of the smaller peaks set upon the lava plateau that -forms the greater part of the Maritime Cordillera, that the snows massed -on their shadier slopes have not yet effected any important topographic -changes. The symmetrical peaks of this class are in a few cases so very -recent that they are entirely uneroded. Lava flows and beds of tuff -appear to have originated but yesterday, and shallow lava-dammed lakes -retain their original shore relations. In a few places an older -topography, glacially modified, may still be seen showing through a -veneer of recent ash and cinder deposits, clear evidence that the -loftier parts of the lava plateau were glaciated before the last -volcanic eruption. - -The asymmetry of the peaks and ridges in the Maritime Cordillera cannot -be ascribed to the manner of eruption, since the contrast in declivity -and form is persistently between northern and southern slopes. Strong -and persistent winds from a given direction undoubtedly influence the -form of volcanoes to at least a perceptible degree. In the case in hand -the ejectamenta are ashes, cinders, and the like, which are blown into -the air and have at least a small component of motion down the wind -during both their ascent and descent. The _prevailing_ winds of the high -plateaus are, however, easterly and the strongest winds are from the -west and blow daily, generally in the late afternoon. Both wind -directions are at right angles to the line of asymmetry, and we must, -therefore, rule out the winds as a factor in effecting the slope -contrasts which these mountains display. - -It remains to be seen what influence a covering of vegetation on the -northern slopes might have in protecting them from erosion. The northern -slopes in this latitude (14° S.) receive a much greater quantity of heat -than the southern slopes. Above 18,000 feet (5,490 m.) snow occurs on -the shady southern slopes, but is at least a thousand feet higher on the -northern slopes. It is therefore absent from the northern side of all -but the highest peaks. Thus vegetation on the northern slopes is not -limited by snow. Bunch grass--the characteristic _ichu_ of the mountain -shepherds--scattered spears of smaller grasses, large ground mosses -called _yareta_, and lichens extend to the snowline. This vegetation, -however, is so scattered and thin above 17,500 feet (5,330 m.) that it -exercises no retarding influence on the run-off. Far more important is -the porous nature of the volcanic material, which allows the rainfall to -be absorbed rapidly and to appear in springs on the lower slopes, where -sheets of lava direct it to the surface. - -The asymmetry of the north and south slopes is not, then, the result of -preglacial erosion, of structural conditions, or of special protection -of the northern slopes from erosion. It must be concluded, therefore, -that it is due to the only remaining factor--snow distribution. The -southern slopes are snow-clad, the northern are snow-free--in harmony -with the line of asymmetry. The distribution of the snow is due to the -contrasts between shade and sun temperatures, which find their best -expression in high altitudes and on single peaks of small extent. -Frankland's observations with a black-bulb thermometer _in vacuo_ show -an increase in shade and sun temperatures contrasts of over 40° between -sea level and an elevation of 10,000 feet. Violle's experiments show an -increase of 26 per cent in the intensity of solar radiation between 200 -feet and 16,000 feet elevation. Many other observations up to 16,000 -feet show a rapid increase in the difference between sun and shade -temperatures with increasing elevation. In the region herein described -where the snowline is between 18,000 and 19,000 feet (5,490 to 5,790 m.) -these contrasts are still further heightened, especially since the -semi-arid climate and the consequent long duration of sunshine and low -relative humidity afford the fullest play to the contrasting forces. The -coefficient of absorption of radiant energy by water vapor is 1,900 -times that of air, hence the lower the humidity the more the radiant -energy expended upon the exposed surface and the greater the sun and -shade contrasts. The effect of these temperature contrasts is seen in a -canting of the snowline on individual volcanoes amounting to 1,500 feet -in extreme instances. The average may be placed at 1,000 feet. - -The minimum conditions of snow motion and the bearing of the conclusions -upon the formation of cirques have been described in the chapters -immediately preceding. It is concluded that snow moves upon 20° slopes -if the snow is at least forty feet deep, and that through its motion -under more favorable conditions of greater depth and gradient and the -indirect effects of border melting there is developed a hollow occupied -by the snow. Actual ice is not considered to be a necessary condition of -either movement or erosion. We may at once accept the conclusion that -the invariable association of the cirques and steepened profiles with -snowfields proves that snow is the predominant modifying agent. - -An argument for glacial erosion based on profiles and steep cirque walls -in a volcanic region has peculiar appropriateness in view of the -well-known symmetrical form of the typical volcano. Instead of varied -forms in a region of complex structure long eroded before the appearance -of the ice, we have here simple forms which immediately after their -development were occupied by snow. _Ever since their completion these -cones have been eroded by snow on one side and by water on the other._ -If snow cannot move and if it protects the surface it covers, then this -surface should be uneroded. All such surfaces should stand higher than -the slopes on the opposite aspect eroded by water. But these assumptions -are contrary to fact. The slopes underneath the snow are deeply -recessed; so deeply eroded indeed, that they are bordered by steep -cliffs or cirque walls. The products of erosion also are to some extent -displayed about the border of the snow cover. In strong contrast the -snow-free slopes are so slightly modified that little of their original -symmetry is lost--only a few low hills and shallow valleys have been -formed. - -The measure of the excess of snow erosion over water erosion is -therefore the difference between a northern or water-formed and a -southern or snow-formed profile, Fig. 200. This difference is also shown -in Fig. 201 and from it and the restored initial profiles we conclude -that the rate of water erosion is to that of nivation as 1:3. This ratio -has been derived from numerous observations on cones so recently formed -that the interfluves without question are still intact. - -Thus far only those volcanoes have been considered which have been -modified by nivation. There are, however, many volcanoes which have been -eroded by ice as well as by snow and water. It will be seen at once that -where a great area of snow is tributary to a single valley, the snow -becomes compacted into névé and ice, and that it then erodes at a much -faster rate. Also a new force--plucking--is called into action when ice -is present, and this greatly accelerates the rate of erosion. While it -lies outside the limits of my subject to determine quantitatively the -ratio between water and ice action, it is worth pointing out that by -this method a ratio much in excess of 1:3 is determined, which even in -this rough form is of considerable interest in view of the arguments -based on the protecting influence of both ice and snow. I have, indeed, -avoided the question of ice erosion up to this point and limited myself -to those volcanoes which have been modified by nivation only, since the -result is more striking in view of the all but general absence of data -relating to this form of erosion. - -[Illustration: FIG. 202--Graphic representation of amount of glacial -erosion during the glacial period. In the background are mature slopes -surmounted by recessed asymmetrical peaks. The river entrenched itself -below the mature slopes before it began to aggrade, and, when -aggradation set in, had cut its valley floor to a'-b'-c. By aggradation -the valley floor was raised to a-b while ice occupied the valley head. -By degradation the river has again barely lowered its channel to a'-b', -the ice has disappeared, and the depression of the profile represents -the amount of glacial erosion. - -a'-b'-c = preglacial profile. - -a-b-d-c = present profile. - -b'-d-c-b = total ice erosion in the glacial period. - -a-b = surface of an alluvial valley fill due to - excessive erosion at valley head. - -b-b' = terminal moraine. - -d-c = cirque wall. - -e, e' e" = asymmetrical summits.] - -[Illustration: FIG. 203--A composite sketch to represent general -conditions in the Peruvian Andes. In order to have the actual facts -represented the profiles of this figure were taken from the accompanying -topographic sheets. The main depression on the right and the -corresponding depression of the tributary profiles bear out most -strikingly the conclusions concerning the erosive power of the ice. At -_A_ and _B_ the spurs have been cut off to exhibit the profiles of -tributary valleys. At _2_ and _3_ were tributary glaciers of such size -that they entered the main valley at grade. Lesser tributaries had -floors elevated above those they joined and now have a hanging -character, as just above _2_. _D_ is a matterhorn; _C_ is deeply -recessed by cirques; _E_ represents a peak just below the limit of -glaciation. At _F_ are the undissected post-mature slopes of an earlier -cycle of erosion. _G_ lies on the steep lower slopes formed during the -canyon cycle of erosion. The down-cutting of the stream in the canyon -cycle was generally checked by glaciation and was superseded by -aggradation.] - -If we now turn to the valley profiles of the glaciated portions of the -Peruvian Andes, we shall see the excess of ice over water erosion -expressed in a manner equally convincing. To a thoughtful person it is -one of the most remarkable features of any glaciated region that the -flattest profiles, the marshiest valley flats, and the most strongly -meandering stretches of the streams should occur near the heads of the -valleys. The mountain shepherds recognize this condition and drive -their flocks up from the warmer valley into the mountain recesses, -confident that both distance and elevation will be offset by the -extensive pastures of the finest _ichu_ grass. Indeed, to be near the -grazing grounds of sheep and llamas which are their principal means of -subsistence, the Indians have built their huts at the extraordinarily -lofty elevations of 16,000 to 17,000 feet. - -An examination of a large number of these valleys and the plotting of -their gradients discloses the striking fact that the heads of the -valleys were deeply sunk into the mountains. It is thus possible by -restoring the preglacial profiles to measure with considerable certainty -the excess of ice over water erosion. - -The results are graphically expressed in Fig. 202. It will be seen that -until glacial conditions intervened the stream was flowing on a rock -floor. During the whole of glacial time it was aggrading its rock floor -below _b'_ and forming a deep valley fill. A return to warmer and drier -conditions led to the dissection of the fill and this is now in -progress. The stream has not yet reached its preglacial profile, but it -has almost reached it. We may, therefore, say that the preglacial valley -profile below _b'_ fixes the position of the present profile just as -surely as if the stream had been magically halted in its work at the -beginning of the period of glaciation. There, _b'-d-c-b_ represents the -amount of ice erosion. To be sure the line _b-c_ is inference, but it is -reasonable inference and, whatever position is assigned to it, it cannot -be coincident with _b'-d_, nor can it be anywhere near it. The break in -the valley profile at _b'_ is always marked by a terminal moraine, -regardless of the character of the rock. This is not an accidental but a -causal association. It proves the power of the ice to erode. In glacial -times it eroded the quantity _b-c-d-b'_. This is not an excess of ice -over water erosion, but an absolute measure of ice erosion, since -_a'-b'_ has remained intact. The only possible error arises from the -position assigned _b-c_, and even if we lower it to _b-c'_ (for which we -have no warrant but extreme conservatism) we shall still have left -_b'-c'-d-b_ as a striking value for rock erosion (plucking and abrasion) -by a valley glacier. - -A larger diagram, Fig. 203, represents in fuller detail the topographic -history of the Andes of southern Peru and the relative importance of -glaciation. The broad spurs with grass-covered tops that end in steep -scarps are in wonderful contrast to the serrate profiles and truncated -spurs that lie within the zone of past glaciation. In the one case we -have minute irregularities on a canyon wall of great dimensions; in the -other, more even walls that define a glacial trough with a flat floor. -Before glaciation on a larger scale had set in the right-hand section of -the diagram had a greater relief. It was a residual portion of the -mountain and therefore had greater height also. Glaciers formed upon it -in the Ice Age and glaciation intensified the contrast between it and -the left-hand section; not so much by intensifying the relief as by -diversifying the topographic forms. - -[Illustration: FIG. 204--Topographic map of the Andes between Abancay -and the Pacific Coast at Camaná. Compiled from the seven accompanying -topographic sheets (see Contents, p. xi). Scale 1:1,000,000. Contour -interval 1,000 feet. Longitude west of Greenwich. The Central Ranges of -the Maritime Cordillera are not confined to the area covered by these -names. In the one case the term includes all the ranges between Lambrama -and Huichihua; in the other case, the peaks and ranges from 14° 30' S. -to Mt. Coropuna.] - - - - -APPENDIX A - -SURVEY METHODS EMPLOYED IN THE CONSTRUCTION OF THE SEVEN ACCOMPANYING -TOPOGRAPHIC SHEETS - -BY KAI HENDRIKSEN, TOPOGRAPHER - - -The main part of the topographical outfit consisted of (1) a 4-inch -theodolite, Buff and Buff, the upper part detachable, (2) an 18 x 24 -inch plane-table with Johnson tripod and micro-meteralidade. These -instruments were courteously loaned the expedition by the U. S. Coast -and Geodetic Survey and the U. S. Geological Survey respectively. - -The method of survey planned was a combination of graphic triangulation -and traverse with the micro-meteralidade. All directions were plotted on -the plane-table which was oriented by backsight; distances were -determined by the micro-meteralidade or triangulation, or both combined; -and elevations were obtained by vertical angles. Finally, astronomical -observations, usually to the sun, were taken at intervals of about 60 -miles for latitude and azimuth to check the triangulation. No -observations were made for differences in longitude because this would -probably not have given any reliable result, considering the time and -instruments at our disposal. Because the survey was to follow very -closely the seventy-third meridian west of Greenwich, directions and -distances, checked by latitude and azimuth observations, undoubtedly -afforded far better means of determining the longitude than time -observations. In other words, the time observations made in connection -with azimuth observations were not used for computing longitudinal -differences. Absolute longitude was taken from existing observations of -principal places. - -Principal topographical points were located by from two to four -intersections from the triangulation and plane-table stations; and -elevations were determined by vertical angle measurements. Whenever -practicable, the contours were sketched in the field; the details of the -topography otherwise depend upon a great number of photographs taken by -Professor Bowman from critical stations or other points which it was -possible to locate on the maps. - - -CROSS-SECTION MAP FROM ABANCAY TO CAMANÁ AT THE PACIFIC OCEAN - -Seven sheets. Scale, 1:125,000; contour interval, 200 feet. Datum is -mean sea level. Astronomical control: 5 latitude and 5 azimuth -observations as indicated on the accompanying topographic sheets. - -On September 10th, returning from a reconnaissance survey of the -Pampaconas River, I joined Professor Bowman's party, Dr. Erving acting -as my assistant. We crossed the Cordillera Vilcapampa and the Canyon of -the Apurimac and after a week's rest at Abancay started the topographic -work near Hacienda San Gabriel south of Abancay. Working up the deep -valley of Lambrama, observations for latitude and azimuth were made -midway between Hacienda Matara and Caypi. - -On October 4th we made our camp in newly fallen snow surrounded by -beautiful glacial scenery. The next day on the high plateau, we passed -sharp-crested glaciated peaks; a heavy thunder and hail storm broke out -while I occupied the station at the pass, the storm continuing all the -afternoon--a frequent occurrence. The camp was made 6 miles farther on, -and the next morning I returned to finish the latter station. I -succeeded in sketching the detailed topography just south of the pass, -but shortly after noon, a furious storm arose similar to the one the day -before, and made further topographic work impossible; to get connection -farther on I patiently kept my eye to the eye-piece for more than an -hour after the storm had started, and was fortunate to catch the station -ahead in a single glimpse. I had a similar experience some days later at -station 16,079, Antabamba Quadrangle, on the rim of the high-level puna, -the storm preventing all topographic work and barely allowing a single -moment in which to catch a dim sight of the signals ahead while I kept -my eye steadily at the telescope to be ready for a favorable break in -the heavy clouds and hail. - -At Antabamba we got a new set of Indian carriers, who had orders to -accompany us to Cotahuasi, the next sub-prefectura. Raimondi's map -indicates the distance between the two cities to be 35 miles, but -although nothing definite was stated, we found out in Antabamba that the -distance was considerably longer, and moreover that the entire route lay -at a high altitude. - -From the second day out of Antabamba until Huaynacotas was in sight in -the Cotahuasi Canyon, a distance of 50 miles, the route lay at an -altitude of from 16,000 to 17,630 feet, taking in 5 successive camps at -an altitude from 15,500 to 17,000 feet; 12 successive stations had the -following altitudes: - - 16,379 feet - 16,852 " - 17,104 " - 17,559 " - 17,675 " --highest station occupied. - 17,608 " - 17,633 " - 16,305 " - 17,630 " - 17,128 " - 16,794 " - 16,260 " - -The occupation of these high stations necessitated a great deal of -climbing, doubly hard in this rarefied air, and often on volcanoes with -a surface consisting of bowlders and ash and in the face of violent -hailstorms that made extremely difficult the task of connecting up -observations at successive stations. - -At Cotahuasi a new pack-train was organized, and on October 25th I -ventured to return alone to the high altitudes in order to continue the -topography at the station at 17,633 feet on the summit of the Maritime -Cordillera. Dr. Erving was obliged to leave on October 18th and -Professor Bowman left a week later in order to carry out his plans for a -physiographic study of the coast between Camaná and Mollendo. Philippi -Angulo, a native of Taurisma, a town above Cotahuasi, acted as majordomo -on this journey. Knowing the trail and the camp sites, I was able to -pick out the stations ahead myself, and made good progress, returning to -Cotahuasi on October 29th, three or four days earlier than planned. From -Cotahuasi to the coast I had the assistance of Mr. Watkins. The most -trying part of the last section of high altitude country was the great -Pampa Colorada, crowned by the snow-capped peaks of Solimana and -Coropuna, reaching heights of 20,730 and 21,703 feet respectively. The -passing of this pampa took seven days and we arrived at Chuquibamba on -November 9th. Two circumstances made the work on this stretch peculiarly -difficult--the scarcity of camping places and the high temperature in -the middle of the day, which heated the rarefied air to a degree that -made long-distance shots very strenuous work for the eyes. Although our -base signals were stone piles higher than a man, I was often forced to -keep my eye to the telescope for hours to catch a glimpse of the -signals; lack of time did not allow me to stop the telescope work in the -hottest part of the day. - -The top of Coropuna was intersected from the four stations: 16,344, -15,545, 16,168, and 16,664 feet elevation, the intersections giving a -very small triangular error. The elevation of Mount Coropuna's high peak -as computed from these 4 stations is: - - 21,696 feet - 21,746 " - 21,714 " - 21,657 " - ------ - Mean elevation 21,703 feet above sea level. - -The elevation of Coropuna as derived from these four stations has thus a -mean error of 18 feet (method of least squares) while the elevation of -each of the four stations as carried up from mean sea level through 25 -stations--vertical angles being observed in both directions--has an -estimated mean error of 30 feet. The result of this is a mean error of -35 feet in Coropuna's elevation above mean sea level. - -The latitude is 15° 31' 00" S.; the longitude is 72° 42' 40" W. of -Greenwich, the checking of these two determinations giving a result -unexpectedly close. - -On November 11th azimuth and latitude observations were taken at -Chuquibamba and two days later we arrived at Aplao in the bottom of the -splendid Majes Valley. In the northern part of this valley I was -prevented from doing any plane-table work in the afternoons of four -successive days. A strong gale set in each noon raising a regular -sandstorm, that made seeing almost impossible, and blowing with such a -velocity that it was impossible to set up the plane-table. - -From Hacienda Cantas to Camaná we had to pass the western desert for a -distance of 45 miles. We were told that on the entire distance there was -only one camping place. This was at Jaguey de Majes, where there was a -brook with just enough water for the animals but no fodder. Thus we -faced the necessity of carrying water for ten men and fodder for 14 -animals in excess of the usual cargo; and we were unable to foretell how -many days the topography over the hot desert would require. - -Although plane-table work in the desert was impossible at all except in -the earliest and latest hours of the day, we made regular progress. We -camped three nights at Jaguey and arrived on the fourth day at Las -Lomas. - -The next morning, on November 23rd, at an elevation of 2178 feet near -the crest of the Coast Range, we were repaid for two months of laborious -work by a glorious view of the Pacific Ocean and of the city of Camaná -with her olive gardens in the midst of the desert sand. - -The next day I observed latitude and azimuth at Camaná and in the night -my companion and assistant Mr. Watkins and I returned across the desert -to the railroad at Vitor. - - -CONCLUSIONS - -The planned methods were followed very closely. In two cases only the -plane-table had to be oriented by the magnetic needle, the backsights -not being obtainable because of the impossibility of locating the last -station, passing Indians having removed the signals. - -In one case only the distance between two stations had to be determined -by graphic triangulation exclusively, the base signals having been -destroyed. Otherwise graphic triangulation was used as a check on -distances. - -Vertical angles were always measured in both directions with the -exception of the above-mentioned cases. - -Observations for azimuth were always taken to the sun before and after -noon. The direction used in the azimuth observation was also taken with -the prismatic compass. The mean of the magnetic declination thus found -is: East 8° 30' plus. - -Observations for latitude were taken to the sun by the method of -circum-meridian altitudes, except at the town of Vilcabamba where star -observations were taken. - -As a matter of course, observations to the sun are not so exact as star -observations, especially in low latitudes where one can expect to -observe the near zenith. However, working in high altitudes for long -periods, moving camp every day and often arriving at camp 2 to 4 hours -after sunset, I found it essential to have undisturbed rest at night. It -was beyond my capacity to spend an hour or two of the night in finding -the meridian and in making the observation. Furthermore, the astronomic -observations were to check the topography mainly, the latter being the -most exact method with the outfit at hand. - -The following table contains the comparisons between the latitude -stations as located on the map and by observation: - - Map Observation - Camaná Quadrangle S 16° 37' 34" 16° 37' 34"[66] - Coropuna, station 9,691S 15° 48' 30" (15° 51' 44") - Cotahuasi, " 12,588S 15° 11' 40" 15° 12' 30" - La Cumbre, " 16,852S 14° 28' 10" 14° 29' 46" - Lambrama, " 8,341S 13° 43' 18" 13° 43' 14" - -The other observations, with the exception of the one on the Coropuna -Quadrangle, check probably as well as can be expected with the small and -light outfit which we used, and under the exceptionally hard conditions -of work. The observation on the Coropuna Quadrangle just south of -Chuquibamba is, however, too much out. An explanation for this is that -the meridian zenith distance was 1° 23' 12" only (in this case the exact -formula was used in computing). Of course, an error or an accumulation -of errors might have been made in the distances taken by the -micrometer-alidade, but the first cause of error mentioned is the more -probable, and this is indicated also by the fact that the location on -the top of Mount Coropuna checks closely with the one determined in an -entirely independent way by the railroad engineers. - -For the cross-section map from Abancay to Camaná, the following -statistics are desirable: - -Micrometer traverse and graphic triangulation, with contours, field -scale 1:90,000. - - Total time required, days 40.5 - Average distance per days in miles 7.5 - Average number of plane-table stations occupied per day 1.5 - Average area per day in square miles 38. - Located points per square mile 0.25 - Approximate elevations in excess of above, per square mile 0.25 - Highest station occupied, feet above sea level 17,675. - Highest point located, feet above sea level 21,703. - - - - -APPENDIX B - -FOSSIL DETERMINATIONS - - -A few fossil collections were gathered in order that age determinations -might be made. With the following identifications I have included a few -fossils (I and II) collected by W. R. Rumbold and put into my hands in -1907. The Silurian is from a Bolivian locality south of La Paz but in -the great belt of shales, slates, and schists which forms one of the -oldest sedimentary series in the Eastern Andes of Peru as well as -Bolivia. While no fossils were found in this series in Peru the rocks -are provisionally referred to the Silurian. Fossil-bearing Carboniferous -overlies them but no other indication of their age was obtained save -their general position in the belt of schists already mentioned. I am -indebted to Professor Charles Schuchert of Yale University for the -following determinations. - - -I. _Silurian_ - - San Roque Mine, southwest slope of Santa Vela Cruz, Canton Ichocu, Province - Inquisivi, Bolivia. - - Sent by William R. Rumbold in 1907. - - _Climacograptus?_ - _Pholidops trombetana_ Clarke? - _Chonetes striatellus_ (Dalman). - _Atrypa marginalis_ (Dalman)? - _Coelospira_ n. sp. - _Ctenodonta_, 2 or more species. - _Hyolithes._ - _Kloedenia._ - _Calymene?_ - _Dalmanites_, a large species with a terminal tail spine. - _Acidaspis._ - -These fossils indicate unmistakably Silurian and probably Middle -Silurian. As all are from blue-black shales, brachiopods are the rarer -fossils, while bivalves and trilobites are the common forms. The faunal -aspect does not suggest relationship with that of Brazil as described by -J. M. Clarke and not at all with that of North America. I believe this -is the first time that Silurian fossils have been discovered in the high -Andes. - - -II. LOWER DEVONIAN - -Near north end of Lake Titicaca. - - _Leptocoelia flabellites_ (Conrad), very common. - _Atrypa reticularis_ (Linnæus)? - -This is a part of the well-known and widely distributed Lower Devonian -fauna of the southern hemisphere. - - -III. _Upper Carboniferous_ - -All of the Upper Carboniferous lots of fossils represent the well-known -South American fauna first noted by d'Orbigny in 1842, and later added -to by Orville Derby. The time represented is the equivalent of the -Pennsylvanian of North America. - -Huascatay between Pasaje and Huancarama. - - Crinoidal limestone. - Trepostomata Bryozoa. - _Polypora._ Common. - _Streptorhynchus hallianus_ Derby. Common. - _Chonetes glaber_ Geinitz. Rare. - _Productus humboldti_ d'Orb. Rare. - " _cora_ d'Orb. Rare. - " _chandlessii_ Derby. - " sp. undet. Common. - " sp. undet. " - _Spirifer condor_ d'Orb. Common. - _Hustedia mormoni_ (Marcou). Rare. - _Seminula argentea_ (Shepard). " - - Pampaconas, Pampaconas valley near Vilcabamba. - - _Lophophyllum?_ - _Rhombopora_, etc. - _Productus._ - _Camarophoria._ Common. - _Spirifer condor_ d'Orb. - _Hustedia mormoni_ (Marcou). - _Euomphalus._ Large form. - - Pongo de Mainique. Extreme eastern edge of Peruvian Cordillera. - - _Lophophyllum._ - _Productus chandlessii_ Derby. - " _cora_ d'Orb. - _Orthotetes correanus_ (Derby). - _Spirifer condor_ d'Orb. - - River bowlders and stones of Urubamba river, just beyond eastern edge of - Cordillera at mouth of Ticumpinea river. (Detached and transported by stream - action from the Upper Carboniferous at Pongo de Mainique.) - - Mostly Trepostomata Bryozoa. - Many _Productus_ spines. - _Productus cora_ d'Orb. - _Camarophoria_. Same as at Pampaconas. - _Productus_ sp. undet. - - Cotahuasi A. - - _Lophophyllum._ - _Productus peruvianus_ d'Orb. - " sp. undet. - _Camarophoria._ - _Pugnax_ near _utah_ (Marcou). - _Seminula argentea_ (Shepard)? - - Cotahuasi B. - - _Productus cora_ d'Orb. - " near _semireticulatus_ (Martin). - - - IV. _Comanchian or Lower Cretaceous_ - - Near Chuquibambilla. - - _Pecten_ near _quadricostatus_ Sowerby. - Undet. bivalves and gastropods. - The echinid _Laganum? colombianum_ d'Orb. A clypeasterid. - -This Lower Cretaceous locality is evidently of the same horizon as that -of Colombia illustrated by d'Orbigny in 1842 and described on pages -63-105. - - - - -APPENDIX C - -KEY TO PLACE NAMES - - -Abancay, town, lat. 12° 35', Figs. 20, 204. - -Abra Tocate, pass, between Yavero and Urubamba valleys, - leaving latter at Rosalina, (Fig. 8). - _See also_ Fig. 55. - -Anta, town, lat. 13° 30', Fig. 20. - -Antabamba, town, lat. 14° 20', Figs. 20, 204. - -Aplao, town, lat. 16°, Figs. 20, 204. - -Apurimac, river, Fig. 20. - -Arequipa, town, lat. 16° 30', Fig. 66. - -Arica, town, northern Chile, lat. 18° 30'. - -Arma, river, tributary of Apurimac, lat. 13° 25', (Fig. 20); - tributary of Ocoña, lat. 15° 30', (Fig. 20). - -Arma, village, lat. 13° 15', Fig. 20. - _See also_ Fig. 140. - -Auquibamba, hacienda, lat. 13° 40', Fig. 204. - - -Callao, town, lat. 12°, Fig. 66. - -Camaná, town, lat. 16° 40', Figs. 20, 66, 204. - -Camisea, river, tributary of Urubamba entering from right, lat. 11° 15'. - -Camp 13, lat. 14° 30'. - -Cantas, hacienda, lat. 16° 15', Fig. 204. - -Caraveli, town, lat. 16°, Fig. 66. - -Catacaos, town, lat. 5° 30', Fig. 66. - -Caylloma, town and mines, lat. 15° 30', Fig. 66. - -Caypi, village, lat. 13° 45'. - -Central Ranges, lat. 14°, Fig. 20. - _See also_ Fig. 157. - -Cerro Azul, town, lat. 13°, Fig. 66. - -Chachani, mt., overlooking Arequipa, lat. 16° 30', (Fig. 66). - -Chaupimayu, river, tributary of Urubamba entering at Sahuayaco, _q.v._ - -Chili, river, tributary of Vitor River, lat. 16° 30', (Fig. 66). - -Chinche, hacienda, Urubamba Valley above Santa Ana, lat. 13°, (Fig. 20). - -Chira, river, lat. 5°, Fig. 66. - -Choclococha, lake, lat. 13° 30', Figs. 66, 68. - -Choqquequirau, ruins, canyon of Apurimac above junction of Pachachaca - River, lat. 13° 25', (Fig. 20). - -Choquetira, village, lat. 13° 20', Fig. 20. - _See also_ Fig. 136. - -Chosica, village, lat. 12°, Fig. 66. - -Chuquibamba, town, lat. 15° 50', Figs. 20, 204. - -Chuquibambilla, village, lat. 14°, Figs. 20, 204. - -Chuquito, pass, Cordillera Vilcapampa between Arma and Vilcabamba - valleys, lat. 13° 10', (Fig. 20). - _See also_ Fig. 139. - -Coast Range, Figs. 66, 204. - -Cochabamba, city, Bolivia, lat. 17° 20', long. 66° 20'. - -Colorada, pampa, lat. 15° 30', Fig. 204. - -Colpani, village, lower end of Canyon of Torontoy (Urubamba River), - lat. 13° 10'. _See_ Fig. 158. - -Copacavana, village, Bolivia, lat. 16° 10', long. 69° 10'. - -Coribeni, river, lat. 12° 40', Fig. 8. - -Coropuna, mt., lat. 15° 30', Figs. 20, 204. - -Corralpata, village, Apurimac Valley near Incahuasi. - -Cosos, village, lat. 16°, Fig. 204. - -Cotabambas, town, Apurimac Valley, lat. 13° 45', (Fig. 20). - -Cotahuasi, town, lat. 15° 10', Figs. 20, 204. - -Cuzco, city, lat. 13° 30', Fig. 20. - - -Echarati, hacienda, on the Urubamba River between Santa Ana and - Rosalina, lat. 12° 40'. - _See_ inset map, Fig. 8, _and also_ Fig. 54. - - -Huadquiña, hacienda, Urubamba River above junction with Vilcabamba, - lat. 13° 10', (Fig. 20). - _See also_ Fig. 158. - -Huadquirca, village, lat. 14° 15', Figs. 20, 204. - -Huaipo, lake, north of Anta, lat. 13° 25', (Fig. 20). - -Huambo, village, left bank Pachachaca River between Huancarama - and Pasaje, lat. 13° 35', (Fig. 20). - -Huancarama, town, lat. 13° 40', Fig. 20. - -Huancarqui, village, lat. 16° 5', Fig. 204. - -Huascatay, village, left bank of Apurimac above Pasaje, - lat. 13° 30', (Fig. 20). - -Huaynacotas, village, lat. 15° 10', Fig. 204. - -Huichihua, village, lat. 14° 10', Fig. 204. - - -(Tablazo de) Ica, plateau, lat. 14°-15° 30', Fig. 66. - -Ica, town, lat. 14°, Figs. 66, 67. - -Incahuasi, village, lat. 13° 20', Fig. 20. - -Iquique, town, northern Chile, lat. 20° 15'. - -(Pampa de) Islay, south of Vitor River, (Fig. 66). - - -Jaguey, village, Pampa de Sihuas, _q.v._ - - -La Joya, pampa, station on Mollendo-Puno R.R., 16° 40', (Fig. 66). - -Lambrama, village, lat. 12° 50', Fig. 20. - -Lima, city, lat. 12°, Fig. 66. - - -Machu Picchu, ruins, gorge of Torontoy, _q.v._, lat. 13° 10'. - -Majes, river, Fig. 204. - -Manugali, river, tributary of Urubamba entering from left - above Puviriari River, lat. 12° 20', (Fig. 8). - -Maritime Cordillera, Fig. 204. - -Matara, village, lat. 14° 20', Fig. 204. - -(El) Misti, mt., lat. 16° 30', Fig. 66. - -Mollendo, town, lat. 17°, Fig. 66. - -Moquegua, town, lat. 17°, Fig. 66. - -Morococha, mines, lat. 11° 45', Fig. 66. - -Mulanquiato, settlement, lat. 12° 10', Fig. 8. - - -Occobamba, river, uniting with Yanatili, _q.v._ - -Ocoña, river, lat. 15°-16° 30', Figs. 20, 66. - -Ollantaytambo, village. Urubamba River below Urubamba town, - lat. 13° 15', (Fig. 20), _and see_ inset map, Fig. 8. - - -Pabellon, hacienda, Urubamba River above Rosalina, (Fig. 20). - _See also_ Fig. 55. - -Pacasmayo, town, lat. 7° 30', Fig. 66. - -Pachatusca (Pachatusun), mt., overlooking Cuzco to northeast, lat. 13° 30'. - -Pachitea, river, tributary of Ucayali entering from left, lat. 8° 50'. - -Paita, town, lat. 5°, Fig. 66. - -Pampacolea, village, south of Coropuna, _q.v._ - -Pampaconas, river, known in lower course as Cosireni, - tributary of Urubamba River, (Fig. 8). - Source in Cordillera Vilcapampa west of Vilcabamba. - -Pampas, river, tributary of Apurimac entering from left, lat. 13° 20'. - -Panta, mt., Cordillera Vilcapampa, northwest of Arma, lat. 13° 15', (Fig. 20). - _See also_ Fig. 136. - -Panticalla, pass, Urubamba Valley above Torontoy, lat. 13° 10'. - -Pasaje, hacienda and ferry, lat. 13° 30', Fig. 20. - -Paucartambo (Yavero), river, _q.v._ - -Paucartambo, town, head of Paucartambo (Yavero) River, - lat. 13° 20', long. 71° 40'. Inset map, Fig. 8. - -Pichu-Pichu, mt., overlooking Arequipa, lat. 16°, (Fig. 66). - -Pilcopata, river, tributary of Upper Madre de Dios - east of Paucartambo, lat. 13°. - -Piñi-piñi, river, tributary of Upper Madre de Dios - east of Paucartambo, lat. 13°. - -Pisco, town, lat. 14°, Fig. 66. - -Piura, river, lat. 5°-6°, Fig. 66. - -Piura, town, lat. 5° 30', Fig. 66. - -Pomareni, river, lat. 12°, Fig. 8. - -Pongo de Mainique, rapids, lat. 12°, Fig. 8. - -Pucamoco, hacienda, Urubamba River, between Santa Ana and Rosalina, (Fig. 20). - -Puquiura, village, lat. 13° 5', Fig. 20. - _See also_ Fig. 158. Distinguish Puqura in Anta basin near Cuzco. - -Puqura, village, Anta basin, east of Anta, lat. 13° 30', (Fig. 20). - - -Quilca, town, lat. 16° 40', Fig. 66. - -Quillagua, village, northern Chile, lat. 21° 30', long. 69° 35'. - - -Rosalina, settlement, lat. 12° 35', Fig. 8. - _See also_ Fig. 20. - - -Sahuayaco, hacienda, Urubamba Valley above Rosalina, (Fig. 20). - _See also_ Fig. 55. - -Salamanca, town, lat. 15° 30', Fig. 20. - -Salaverry, town, lat. 8°, Fig. 66. - -Salcantay, mt., lat. 13° 20', Fig. 20. - -San Miguel, bridge, canyon of Torontoy near Machu Picchu, lat. 13° 10'. - -Santa Ana, hacienda, lat. 12° 50', Fig. 20. - -Santa Ana, river, name applied to the Urubamba in the - region about hacienda Santa Ana. - -Santa Lucia, mines, lat. 16°, Fig. 66. - -Santo Anato, hacienda, La Sama's hut, 12° 35', Fig. 8. - -Sihuas, Pampa de, lat. 16° 30', Fig. 204. - -Sillilica, Cordillera, east of Iquique, northern Chile. - -Sintulini, rapids of Urubamba River above junction of - Pomareni, lat. 12° 10', (Fig. 8). - -Sirialo, river, lat. 12° 40', Fig. 8. - -Soiroccocha, mt., Cordillera Vilcapampa north of Arma, - lat. 13° 15', (Fig. 20). - -Solimana, mt., lat. 15° 20', Fig. 204. - -Soray, mt., Cordillera Vilcapampa, southeast of Mt. Salcantay, - lat. 13° 20', (Fig. 20). - -Sotospampa, village, near Lambrama, lat. 13° 50', (Fig. 204). - -Sullana, town, Chira River, lat. 5°, (Fig. 66). - - -Taurisma, village, lat. 15° 10', Fig. 204. - -Ticumpinea, river, tributary of Urubamba entering from right - below Pongo de Mainique, lat. 11° 50', (Fig. 8). - -Timpia, river, tributary of Urubamba entering from right, lat. 11° 45'. - -Tono, river, tributary of Upper Madre de Dios, east of Paucartambo, lat. 13°. - -Torontoy, canyon of the Urubamba between the villages of Torontoy - and Colpani, lat. 13° 10'-13° 15'. - -Torontoy, village at the head of the canyon of the same name, lat. 13° 15'. - _See_ inset map, Fig. 8. - -Tumbez, town, lat. 4° 30', Fig. 66. - -Tunari, Cerro de, mt., northwest of Cochabamba, _q.v._ - - -Urubamba, river, Fig. 20. - -Urubamba, town, lat. 13° 20', Fig. 20. - - -Vilcabamba, river, tributary of Urubamba River entering from - left above Santa Ana, lat. 13°, Fig. 8. - _See also_ Fig. 158. - -Vilcabamba, village, lat. 13° 5', Fig. 20. - _See also_ Fig. 158. - -Vilcanota, Cordillera, southern Peru. - -Vilcanota, river, name applied to Urubamba above lat. of - Cuzco, 13° 30', (Fig. 20). - -Vilcapampa, Cordillera, lat. 13° 20', Fig. 20. - -Vilque, town, southern Peru, lat. 15° 50', long. 70° 30'. - -Vitor, pampa, lat. 16° 30', Fig. 66. - -Vitor, river, Fig. 66. - - -Yanahuara, pass, between Urubamba and Yanatili valleys, lat. 13° 10'. - -Yanatili, river, tributary of Urubamba entering from right - above Rosalina, (Fig. 20). - _See also_ Fig. 65. - -Yavero (Paucartambo), river, tributary of Urubamba entering - from right, lat. 12° 10', Fig. 8. - -Yavero, settlement, at junction of Yavero and Urubamba - rivers, lat. 12° 10', Fig. 8. - -Yunguyo, town, southern Peru, lat. 16° 20', long. 69° 10'. - -Yuyato, river, lat. 12° 5', Fig. 8. - - - - -INDEX - - -Abancay, 32, 62, 64, 78, 92, 93, 181, 189, 221, 243; - suppressing a revolution, 89-91; - temperature curve (diagr.), opp. p. 180 - -Abancay basin, 154 - -Abancay to Camaná cross-section map, work, observation and statistics, 315 - -Abra Tocate, 73, 80, 81; - topography and vegetation from (ill.), opp. p. 19 - -Abra de Malaga, 276 - -Acosta, 205 - -Adams, G. I., 255 - -Agriculture, 74-76, 152 - -Aguardiente, 74. _See_ Brandy - -Alcohol, 5, 6 - -Alluvial fans, 60-63, 70, 270 - -Alluvial fill, 270-273; - view in Majes Valley (ill.), opp. p. 230 - -Alpacas, 5, 52 - -Alto de los Huesos (ill.), opp. p. 7 - -Amazon basin, Humboldt's dream of conquest, 33-35; - Indian tribes, 36 - -Amazonia, 20, 26 - -Ancachs, 171 - -Andahuaylas, 89 - -Andrews, A, C., 295 - -Angulo, Philippi, 317 - -Anta, 187, 189, 190 - -Anta basin, 62, 108, 197; - geology, 250; - view looking north from hill near Anta (ill.), opp. p. 184 - -Antabamba, 52, 53, 95, 96, 99, 101, 189, 197, 243, 303, 316; - Governor, 95-99, 100-101; - Lieutenant Governor, 96-99, 101; - sketch section, 243 - -Antabamba Canyon, view across (ill.), opp. p. 106 - -Antabamba Quadrangle, 316, opp. p. 282 (topog. sheet) - -Antabamba region, geologic sketch map and section, 245 - -Antabamba Valley, 96 - -"Antis," 39 - -Aplao, 106, 115, 116, 181, 226, 231, 255, 256, 257, 273, 318; - composite structure section (diagr.), 259; - temperature curve (diagr.), 181 - -Aplao Quadrangle (topog. sheet), opp. p. 120 - -Appendix A, 315 - -Appendix B, 321 - -Appendix C, 324 - -Apurimac, 51, 57, 60, 94, 153, 154; - crossing at Pasaje (ills.), opp. p. 91; - regional diagram of canyoned country, 58 - -Apurimac Canyon, 189; - cloud belt (ill.), opp. p. 150 - -Arequipa, 52, 89, 92, 117, 120, 137, 284; - glacial features near (sketches), 280 - -Argentina, 93 - -Arica, 130, 132, 198 - -Arma, 67, 189, 212-214 - -Arrieros, Pampa de, 280 - -Asymmetrical peaks (ill.), opp. p. 281 - -Asymmetry, 305-313; - cross-section of ridge (diagr.), 306; - postglacial volcano (diagr.), 306 - -Auquibamba, 93 - -Avalanches, 290 - - -Bailey, S. I., 284 - -Bandits, 95 - -Basins, 60, 154; - regional diagram, 61; - climatic cross-section (diagr.), 62 - -Batholith, Vilcapampa, 215-224 - -Belaunde brothers, 116 - -Bergschrunds, 294-305 - -Bingham, Hiram, ix, 104, 157 - -Block diagram of physiography of Andes, 186 - -Boatmen, Indian, 13 - -Bogotá, Cordillera of, 205 - -Bolivia, 93, 176, 190, 193, 195, 240, 241, 249, 322; - snowline, 275-277 - -Bolivian boundary, 68 - -Border valleys of the Eastern Andes, 68-87 - -Borneo, 206 - -Bowman, Isaiah, 8, 316 - -Brandy, 74, 75, 76, 82-83 - -Bravo, José, 245 - -Bumstead, A. H., ix - - -Cacao, 74, 83 - -Cacti, 150; - arboreal (ill.), opp. p. 90 - -Calchaquí Valley, 250 - -Callao, 118; - cloudiness (with diagr.), 133; - temperature (with diagr.), 126-129; - wind roses (diagrs.), 128 - -Camaná, 21, 112, 115, 116, 117, 118, 140-141, 147, 181, - 225, 226, 227, 266, 318; - coastal Tertiary, 253, 254; - plain of, 229; - temperature curve (diagr.), 181 - -Camaná Quadrangle (topog. sheet), opp. p. 114 - -Camaná Valley, 257 - -Camaná-Vitor region, 117 - -Camino del Peñon, 110 - -Camisea, 36 - -Camp 13, 100, 180, 181; - temperature curve (diagr.), 180 - -Campas, 37 - -Canals for bringing water, 59, 60, 155; - projected, Maritime Cordillera (diagr.), 118 - -Cantas, 115, 116, 226, 253, 257, 273, 318 - -Canyon walls (ills.), opp. p. 218 - -Canyoned country, regional diagram, 58; - valley climates (diagr.), 59 - -Canyons, 60, 72, 73, 197, 219; - Majes River (ill.), opp. p. 230; - topographic conditions before formation of deep - canyons in Maritime Cordillera (ill.), opp. p. 184 - -Caraveli, climate data, 134-136; - wind roses (diagrs.), 136 - -Carboniferous fossils, 323 - -Carboniferous strata, 241-247; - hypothetical distribution of land and sea (diagr.), 246 - -Cashibos, 37 - -Catacaos, 119 - -Cattle tracks (ill.), opp. p. 226 - -Caucho, 29 - -Caylloma, 164, 165 - -Caypi, 316 - -Central Ranges, asymmetrical peaks (ill.), opp. p. 281; - glacial features with lateral moraines (ill.), opp. p. 269; - glacial topography between Lambrama and Antabamba (ill.), opp. p. 280; - steep cirque walls (ill.), opp. p. 286 - -Cerro Azul, 118 - -Cerro de Tunari, 176 - -Chachani, 280, 284 - -Chanchamayo, 77 - -Character. _See_ Human character - -Chaupimayu Valley, 77 - -_Chicha_, 86 - -Chile, 130, 132, 193, 260 - -Chili River, 120 - -Chili Valley, opp. p. 7 (ill.), 117 - -Chimborazo, 281 - -Chinche, 271, 272 - -Chira River, depth diagram, 119, 120 - -Chirumbia, 12 - -Choclococha, Lake, 120 - -Chonta Campas, 37 - -Choqquequirau, 154 - -Choquetira, 66, 67, 211; - bowldery fill below, 269; - glacial features, 206-207 - -Choquetira Valley, moraine, (ill.), opp. p. 208 - -Chosica, 136, 137; - cloudiness (diagr.), 138 - -_Chuño_, 57 - -Chuntaguirus, 41 - -Chuquibamba, 54, 72, 107, 110, 111, 112, 115, 116, 273, 317-319; - sediments, 258 - -Chuquibambilla, 53, 189, 220, 221, 222, 236, 243; - alluvial fill (diagr.), 272; - Carboniferous, 244; - fossils, 323 - -Chuquito pass, crossing (ill.), opp. p. 7; - glacial trough (ill.), opp. p. 205 - -Cirque walls, steep (ill.), opp. p. 286 - -Cirques, 294-305; - development (diagr.), 300; - development, further stages (diagr.), 301; - mode of formation (diagr.), 297 - -Clarke, J. M., 321 - -Clearing in forest (ill.), opp. p. 25 - -Climate, coast, 125-147; - eastern border, 147-153; - Inter-Andean valleys, 153-155; - _see also_ Meteorological records - -Climatic belts, 121-122; - map, 123 - -Climatology, 121-156 - -Cliza, 276 - -Cloud-banners, 16 - -Cloud belt, 143, opp, p. 150 (ill.) - -Cloudiness, 132; - Callao (with diagr.), 133; - desert station near Caraveli (diagrs.), 137; - Machu Picchu, 160; - Santa Lucia (diagr.), 169 - -Clouds, Inter-Andean Valley, 155; - Santa Ana (ill.), opp. p. 180; - Santa Lucia, 168; - types on eastern border of Andes (diagrs.), 148; - _see also_ Fog - -Coast Range, 111, 113, 114, 116, 118, 225-232; - climate, 122-147; - direction, 267; - diagram to show progressive lowering of saturation - temperature in a desert, 127; - geology, 258; - view between Mollendo and Arequipa in June (ill.), opp. p. 226; - wet and dry seasons (diagrs.), 132 - -Coastal belt, map of irrigated and irrigable land, 113 - -Coastal desert, 110-120; - regional diagram of physical relations, 112; - _see also_ Deserts - -Coastal planter, 6 - -Coastal region, topographic and climatic provinces (diagr.), 125 - -Coastal terraces, 225-232 - -Coca, 74, 77, 82-83 - -Coca seed beds (ill.), opp. p. 74 - -Cochabamba, 93; - temperature (diagrs. of ranges), insert opp. p. 178; - weather data, 176-178 - -Cochabamba Indians, 276 - -Colombia, 205 - -Colorada, Pampa de, 114, 317 - -Colpani, 72, 215, 216, 222, 223; - from ice to sugar cane (ill.), opp. p. 3 - -Comanchian fossils, 323 - -Cómas, 155 - -Compañia Gomera de Mainique, 29, 31, 32 - -Concession plan, 29 - -Conibos, 44 - -_Contador_, 84-85 - -Copacavana, 176 - -Cordilleras, 4, 6, 20, 197 - -Coribeni, 15 - -Corn, 57, 59, 62 - -Coropuna, 109, 110, 112, 202, 253, 317, 319; - elevation, 317; - glaciation, 307; - snowline, 283-285 - -Coropuna expedition, 104 - -Coropuna Quadrangle, 197, opp. p. 188 (topog. sheet), 319 - -Corralpata, 51, 59 - -Cosos, 231 - -Cotabambas, 78 - -Cotahuasi, 4, 5, 52, 54, 60, 97, 101, 103, 104, 180, 197, 199, 316, 317; - alluvial fill, 272; - fossils, 322; - geologic sketch maps and cross-section, 247; - rug weaver (ill.), opp. p. 68; - snowline above, 282-283; - temperature curve (diagr.), 180; - view (ill.), opp. p. 57 - -Cotahuasi Canyon, 247, 248, 316 - -Cotahuasi Quadrangle (topog. sheet), opp. p. 192 - -Cotahuasi Valley, geology, 258 - -Cotton, 76, 116, 117 - -Crest lines, asymmetrical, 305-313 - -Cretaceous formations, 247-251 - -Cretaceous fossils, 323 - -Crucero Alto, 188 - -Cuzco, 8, 10, 21, 52, 62, 63, 92, 102, 107, 193, 197; - railroad to Santa Ana, 69-70; - snow, 276; - view (ill.), opp. p. 66 - -Cuzco basin, 61, 62, 154, 251; - slopes at outlet (diagr.), 185 - - -Deformations. _See_ Intrusions - -Derby, Orville, 322 - -Desaguadero Valley, 193 - -Deserts, cloudiness (diagrs.), 137; - rain, 138-140; - sea-breeze in, 132; - tropical forest, 36-37; - wind roses (diagrs.), 136 - -Diagrams. _See_ Regional diagrams - -Dikes, 223 - -Drunkenness, 103, 105-106, 108 - -Dry valleys, 114-115 - -Dunes, 114, 254; - Majes Valley, 262-267; - movement, 132; - superimposed (diagrs.), 265 - -Duque, Señor, 78 - - -Eastern Andes, 204-224; - regional diagram, 22 - -Eastern border, climate, 147-153 - -Eastern valley planter, 3 - -Eastern valleys, 68-87; - climate cross-section (diagr.), 79 - -Echarati, 10, 77, 78, 80, 82; - plantation scene (ill.), opp. p. 75 - -Ecuador volcanoes, 281 - -Epiphyte (ill.), opp. p. 78 - -Erdis, E. C., 158 - -Erosion, 192-195, 210, 211, 305; - _see also_ Glacial erosion; Nivation - -Erving, Dr. W. G., 13, 101, 316, 317 - - -_Faena_ Indians, 75, 83-87 - -Feasts and fairs, 175-176 - -Ferries, 147 - -Fig tree (ill.), opp. p. 75 - -Floods, 151 - -Fog, 132, 139, 143; - conditions along coast from Camaná to Mollendo, 144-145; - _see also_ Clouds - -Forest dweller, 1 - -Forest Indians. _See_ Machigangas - -Forests, clearing (ill.), opp. p. 25; - dense ground cover, trees, epiphytes, and parasites (ill.), opp. p. 155; - moss-draped trees (ill.), opp. p. 24; - mountain, 148-153; - mule trail (ill.), opp. p. 18; - tropical, near Pabellon (ill.), opp. p. 150; - tropical vegetation (ill.), opp. p. 18; - type at Sahuayaco (ill.), opp. p. 90 - -Fossils, 245, 321; - list of, by geologic periods and localities, 321 - -Frankland, 278, 309 - -Frost line, 56-57 - - -Garua, 132 - -Geographical basis of revolutions and of human character, 88-109 - -Geologic dates, 195-196; - Majes Valley, 258, 261; - west coast fault, 248-249 - -Geologic development. _See_ Physiographic and geologic development - -Gilbert, G. K., 300, 302, 305 - -Glacial deposits, 268 - -Glacial erosion, Central Andes, 305-313; - composite sketch of general conditions, 312; - graphic representation of amount during glacial period, 311 - -Glacial features, 274-313; - Arequipa (sketches), 280; - Central Ranges; lateral moraines (ill.), opp. p. 269; - eastern slopes of Cordillera Vilcapampa (map), 210 - -Glacial retreat, 208-214 - -Glacial sculpture, heart of the Cordillera Vilcapampa (map), 212; - southwestern flank of Cordillera Vilcapampa (map), 207 - -Glacial topography between Lambrama and Antabamba (ill.), opp. p. 280; - Maritime Cordillera, north of divide on 73d meridian (ill.), opp. p. 281 - -Glacial trough, view near Chuquito pass (ill.), opp. p. 208 - -Glaciation, 64, 271; - Sierra Nevada, 305; - Vilcapampa, 204-214; - Western Andes, 202 - -Glaciers, Panta Mountain (ill.), opp. p. 287; - view (ill.), opp. p. 205 - -Gomara, 34 - -Gonzales, Señor, 78 - -Government, bad, 95 - -Gran Pajonal, 37 - -Granite, 215-224; - _see also_ Intrusions - -Grass (ill.), opp. p. 154 - -Gregory, J. W., 205 - - -_Hacendado_, 55, 60 - -_Haciendas_, 78, 83, 86 - -Hann, J., 126, 176, 278 - -Hendriksen, Kai, 98, 315 - -Hettner, 205 - -Hevea, 29 - -Highest habitations in the world, 52, 96; - regional diagram of, 50; - stone hut (ill.), opp. p. 48 - -Highland shepherd, 4 - -Highlands, 46 - -Hobbs, W. H., 286, 287 - -Horses, 66, opp. p. 91 (ill.) - -Huadquiña, 70, 71, 72, 75, 82, 86, 219; - hacienda (ill.), opp. p. 73; - terraces, 272 - -Huadquirca, 243 - -Huaipo, Lake, 250, 251 - -Huallaga basin, 153 - -Huambo, 243 - -Huancarama, 64, 87, 189, 243, 303; - view (ill.), opp. p. 106 - -Huancarqui, 257 - -Huari, 176 - -Huascatay, 189, 242, 243; - Carboniferous, 244; - fossils, 322 - -Huasco basin, 275 - -Huaynacotas, 103, 316; - terraced valley slope (ill.), opp. p. 56; - terraced valley slopes (ill.), opp. p. 199 - -Huichihua, 278; alluvial fill (diagr.), 272; - (ill.), opp. p. 67 - -Human character, geographic basis, 88-109 - -Humboldt, 33-35, 286 - -Humboldt Current, 126, 143 - -Huts, 103; - highest in Peru (ill.), opp. p. 48; - shepherds', 47, 48, 52, 55 - - -Ica Valley, 120; - irrigated and irrigable land (diagr.), 118 - -Ice erosion. _See_ Glacial erosion - -Incahuasi, 51, 155, 285 - -Incas, 39, 44, 46, 62, 63, 68, 77, 109, 175 - -Incharate, 78 - -Indian boatmen, 13 - -Indians, as laborers, 26-28, 31-32; - basin type, 63-64; - forest, _see_ Machigangas; - life and tastes, 107-108; - mountain, 46-67, 101-102; - plateau, 40-41, 44-45, 100, 106-109; - troops, 90, 91; - wrongs, 14, 102 - -Ingomwimbi, 206 - -Instruments, surveying, 315 - -Inter-Andean valleys, climate, 153-155 - -Intermont basin. _See_ Basins - -Intrusions, deformations north of Lambrama (diagr.), 243; - deformative effects on limestone strata near Chuquibambilla (diagr.), 221; - lower Urubamba Valley (geologic sketch map), 237; - overthrust folds in detail near Chuquibambilla (diagr.), 222; - principles, 217-219 - -Intrusions, Vilcapampa, deformative effects near Puquiura (diagr.), 216; - relation of granite to schist near Colpani (with diagr.), 216 - -Iquique, wind roses (diagrs.), 131 - -Irrigation, 72, 76, 80, 82; - coastal belt (map), 113; - coastal desert, 119-120; - Ica Valley (diagr.), 118 - -Islay, Pampa de, 114 - -Italians, 18, 81 - - -Jaguey, 254, 255, 318 - -Jesuits, 68 - -Johnson, W. D., 213, 295, 296, 299, 300 - - -Kenia, Mt., 206, 274 - -Kerbey, Major, 8, 10 - -Kibo, 206, 274 - -Kilimandjaro, 205, 206 - -Kinibalu, 206 - -Krüger, Herr, 157 - - -Labor, 26-28, 31-32, 42-43, 74-75, 83-84 - -La Cumbre Quadrangle, 197, 202, opp. p. 202 (topog. sheet) - -La Joya, 132, 133; - cloudiness (diagr.), 134; - temperature curves (diagr.), 134; - wind roses (diagrs.), 135 - -Lambrama, 90, 92, 285, 316; - camp near (ill.), opp. p. 6 - -Lambrama Quadrangle (topog. sheet), opp. p. 304 - -Lambrama Valley, deformation types (diagr.), 243 - -Land and sea, Carboniferous hypothetical distribution - compared with present (diagr.), 246 - -Landscape, 183-198 - -Lanius, P. B., 13 - -La Paz, 93, 109, 276, 321 - -La Sama, 12, 13, 40 - -Las Lomas, 318 - -Lava flows, 199 - -Lava plateau, 197, 199, 307-308; - regional diagram of physical conditions, 55; - summit above Cotahuasi (ill.), opp, p. 204 - -Lavas, volume, 201 - -Lima, 92, 93, 118, 137, 138; - cloud, 132, 143; - temperature, 126 - -Limestone, sketch to show deformed, 243 - -Little, J. P., 135, 157 - -Llica, 275 - -Lower Cretaceous fossils, 323 - -Lower Devonian fossils, 321 - - -Machigangas, 10, 11, 12, 14, 18, 19, 31, 36-45, 81; - ornaments and fabrics (ill.), opp. p. 27; - trading with (ill.), opp. p. 26 - -Machu Picchu, 72, 220; - weather data (with diagr.), 158-160 - -Madeira-Mamoré railroad, 33 - -Madre de Dios, 1, 2, 33 - -Majes River, 147, 225, 227, 266, 267; - Canyon (ill.), opp. p. 230 - -Majes Valley, 106, 111, 116, 117, 120, 226, 227, 229-231, 318; - alluvial fill, 273; - date of formation, 258, 261; - desert coast (ill.), opp. p. 110; - dunes, 262-267; - erosion and uplift, 261; - lower and upper sandstones (ill.), opp. p. 250; - sediments, 255; - snowline, 283; - steep walls and alluvial fill (ill.), opp. p. 230; - structural details near Aplao (sketch section), 255; - structural details on south wall near Cantas (sketch section), 257; - structural relations at Aplao (field sketch), 256; - Tertiary deposits, 253-254; - wind, 130; - view below Cantas (ill.), opp. p. 110; - view down canyon (ill.), opp. p. 144 - -Malaria, 14, 38 - -Marañon, 41, 59 - -Marcoy, 79 - -Marine terrace at Mollendo (ill.), opp. p. 226 - -Maritime Cordillera, 52, 199-203, 233; - asymmetry of ridges, 308-309; - glacial features, 307; - glacial topography north of divide on 73d meridian (ill.), opp. p. 281; - pre-volcanic topography, 200; - post-glacial volcano, asymmetrical (diagr.), 306; - regional diagrams, 50, 52; - test of explanation of cirques, 303; - volcanoes, tuffs, lava flows (ill.), opp. p. 204; - western border rocks (geologic section), 257; - _see also_ Lava plateau - -Matara, 99, 316 - -Matthes, F. E., 286, 287, 289 - -Mature slopes, 185-193; between Ollantaytambo and Urubamba - (ill.), opp. p. 185; - dissected, north of Anta (ill.), opp. p. 185 - -Mawenzi, 206 - -Meanders, 16, 17 - -Médanos, 114 - -Mendoza, Padre, 11 - -Mer de Glace, 203 - -Meteorological records, 157-181 - -Mexican revolutions, 93 - -Middendorf, 143 - -Miller, General, 41, 78, 147 - -Minchin, 241 - -Misti, El, opp. p. 7 (ill.), 284 - -Molina, Christoval de, 175 - -Mollendo, 93, 105, 117; - cloud belt, 143; - cloudiness (diagr.), 134; - coastal terraces, 225; - humidity, 133; - marine terrace (ill.), opp. p. 226; - profile of coastal terraces (diagr.), 227; - temperature curves (diagr.), 134; - wind roses (diagrs.), 129 - -Mollendo-Arequipa railroad, 117 - -Mollendo rubber, 32 - -Montaña, 148, 149, 153 - -Moquegua, 117; - geologic relations (diagr.), 255 - -Moraines, 207, 210-211; - Choquetira Valley (ill.), opp. p. 208; - view (ill.), opp. p. 208 - -Morales, Señor, 11 - -Morococha, temperature (diagrs. of ranges), insert opp. p. 172; - weather data (with diagrs.), 171-176 - -Morococha Mining Co., 157, 171 - -Morro de Arica, 132 - -Moss, large ground. _See Yareta_ - -Moss-draped trees (ill.), opp. p. 24 - -Mountain-side trail (ill.), opp. p. 78 - -Mountains, tropical, as climate registers, 206 - -Mulanquiato, 10, 18, 19 - -Mule trail (ill.), opp. p. 18 - -Mules, 23, 24, 94, opp. p. 91 (ill.) - - -Névé, 286-305 - -Niño, El, 137-138 - -Nivation, 285-294; - "pocked" surface (ill.), opp. p. 286 - -Northeastern border, topographic and structural section (diagr.), 241 - - -Occobamba Valley, 79 - -Ocean currents of adjacent waters, 121-122 (map), 123 - -Ollantaytambo, 70, 73, 75, 250, 271; - terraced valley floor (ill.), opp. p. 56 - -d'Orbigny, 322 - -Oruro, 93 - - -Pabellon, 80, 82, opp. p. 150 - -Pacasmayo, Carboniferous land plants, 245 - -Pachitea, 37, 38 - -Pacific Ocean basin, 248 - -Paleozoic strata (ill.), opp. p. 198 - -_Palma carmona_, 29 - -Palmer, H. S., 250 - -Paltaybamba, opp. p. 74 - -Pampacolca, 109 - -Pampaconas, 69, 211, 213, 215; - rounded slopes near Vilcabamba (ill.), opp. p. 72; - Carboniferous, 244; - fossils, 322; - snow action, 291 - -Pampaconas River, 316 - -Pampas, 114, 198; - climate data, 134-136 - -Pampas, river, 189 - -Panta, mt., 214; - view, with glacier system (ill.), opp. p. 287 - -Pará rubber, 32 - -Pasaje, 51, 57, 59, 60, 236, 238, 240, 241, 243; - Carboniferous, 244; - crossing the Apurimac (ills.), opp. p. 91 - -Paschinger, 274 - -Pastures, 141, 187; - Alpine (ill.), opp. p. 58 - -Paucartambo, 42, 77 - -Paucartambo River. _See_ Yavero River - -Payta, 225 - -Penck, A., 205 - -Peonage, 25, 27, 28 - -Pereira, Señor, 10, 18 - -Perene, 155 - -Physiographic and geologic development, 233-273 - -Physiographic evidence, value, 193-195 - -Physiographic principles, 217 - -Physiography, 183-186; - Southern Peru, summary, 197-198 - -Pichu-Pichu, 284 - -Piedmont accumulations, 260 - -Pilcopata, 36 - -Piñi-piñi, 36 - -Pisco, 130; - Carboniferous land plants, 247 - -Piura, 119 - -Piura River, depth diagram, 119, 120 - -Piura Valley, 48 - -Place names, key to, 324 - -Plantations, 86; - _see also_ Haciendas - -Planter, coastal, 6 - -Planters, valley, 3, 75, 76 - -Plateau Indians, 40-41, 44-45, 100, 106-109 - -Plateaus, 196-197 - -Pleistocene deposits, 267-273 - -Pomareni, 19 - -Pongo de Mainique, 8, 9, 11, 15-20, 40, 71, 179, 239, 241, 242, 273; - canoe in rapid above (ill.), opp. p. 11; - Carboniferous, 244; - dugout in rapids below (ill.), opp. p. 2; - fossils, 322; - temperature curve (diagr.), 178; - upper entrance (ill.), opp. p. 10; - vegetation, clearing, and rubber station (ill.), opp. p. 2 - -Poopó, 195 - -Potato field (ill.), opp p. 67 - -Potatoes, 57, 59, 62 - -Potosí, 249 - -Precipitation. _See_ Rain - -Profiles, composition of slopes and profiles (diagr.), 191 - -Pucamoco, 78 - -Pucapacures, 42 - -Puerto Mainique, 29, 30 - -Punas, 6, 197 - -Puquiura, 67, 87, 211, 216, 236, 238, 239, 243, 277; - Carboniferous, 244; - composition of slopes (ill.), opp. p. 198 - -Puqura, 250 - - -Quebradas, 145, 155 - -Quechuas, 44, 45, 77, 83 - -_Quenigo_, 285 - -Quilca, 105, 117, 226, 266 - -Quillabamba, opp. p. 74 - -Quillagua, 260 - - -Railroads, 74, 75, 76, 93, 101-102, 149; - Bolivia, 93; - Cuzco to Santa Ana, 69-70 - -Raimondi, 77, 78, 109, 110, 135, 155, 170, 316 - -Rain, 115, 119, 120, 122, 124-125; - coast region seasonal variation, 131-137; - eastern border of Andes, belts (diagrs.), 148; - effect of heavy, 138-140; - effect of sea-breeze, 131-132; - heaviest, 147-148; - Morococha (with diagrs.), 173-176; - periodic variations, 137; - Santa Lucia (with diagrs.), 164-166; - unequal distribution in western Peru, 145-147 - -Regional diagrams, 50; - index map, 23; - note on, 51 - -Regions of Peru, 1, 7 - -Reiss, 205, 208 - -Revolutions, geographic basis, 88-109 - -Rhone glacier, 205 - -Rice, 76 - -Robledo, L. M., 9, 30, opp. p. 78 - -Rock belts, outline sketch along 73d meridian, 235 - -Rocks, Maritime Cordillera, pampas and Coast Range structural - relations (sketch section), 254; - Maritime Cordillera, western border (geologic section), 257; - Moquegua, structural relations (diagr.), 255; - Urubamba Valley, succession (diagr.), 249 - -Rosalina, 8, 9, 10, 11, 37, 42, 71, 73, 80, 82, 153, 237 - -Rubber, 18; - price, 32, 33 - -Rubber forests, 22-35 - -Rubber gatherers, Italian, 18, 81 - -Rubber plant (ill.), opp. p. 75 - -Rubber trees, 152 - -Rueda, José, 78 - -Rug weaver (ill.), opp. p. 68 - -Rumbold, W. R., 321 - -Russell, I. C., 205 - -Ruwenzori, 206, 274 - - -Sacramento, Pampa del, 37 - -Sahuayaco, 77, 78, 80, 83, 179; - forests (ills.), opp. p. 90; - temperature curve (diagr.), 178 - -Salamanca, 54, 56, 105, 106, 180, 181; - forest, 285; - temperature curve (diagr.), 180; - terraced hill slopes (ill.), opp. p. 58; - view (ill.), opp. p. 107 - -Salaverry, 119 - -Salcantay, 64, 72, opp. p. 3 (ill.) - -San Geronimo, 276 - -Sand. _See_ Dunes - -"Sandy matico" (ill.), opp. p. 90 - -San Gabriel, Hacienda, 316 - -Santa Ana, 69, 72, 78, 79, 80, 82, 93, 153, 179, 237; - clouds (ill.), opp. p. 180; - temperature curve (diagr.), 178 - -Santa Ana Valley, 10, 82 - -Santa Lucia, temperature ranges (diagrs.), insert opp. p. 162; - unusual weather conditions, 169-170; - weather data (with diagrs.), 161-171 - -Santo Anato, 40, 42, 82, 179; - temperature curve (diagr.), 178 - -Schists and Silurian slates, 236-241 - -Schrund. _See_ Bergschrunds - -Schrundline, 300-305 - -Schuchert, Chas., 321 - -Sea and land. _See_ Land and sea - -Sea-breeze, 129-132 - -Shepherd, highland, 4 - -Shepherds, country of, 46-67 - -Shirineiri, 36, 38 - -Sierra Nevada, 305 - -Sierra Nevada de Santa Marta, 205 - -Sievers, W., 143, 176, 205, 263 - -Sihuas, Pampa de, 114, 198 - -Sillilica, Cordillera, 190, 260 - -Sillilica Pass, 275 - -Silurian fossils, 321 - -Silurian slates, 236-241 - -Sintulini rapids, 19 - -Sirialo, 8, 15 - -Slave raiders, 14 - -Slavery, 24, 25 - -Slopes, composition at Puquiura (ill.), opp. p. 198; - composition of slopes and profiles (diagr.), 191; - smooth grassy (ill.), opp. p. 79; - _see also_ Mature slopes - -Smallpox, 14, 38 - -Snow, 212; - drifting, 278; - fields on summit of Cordillera Vilcapampa (ill.), opp. p. 268 - -Snow erosion. _See_ Nivation - -Snow motion, curve of (diagr.), 293; - law of variation, 291 - -Snowline, 52, 53, 66, 122, 148, 203, 205-206, 274-285; - canting (with diagr.), 279; - determination, 282; - difference in degree of canting (diagr.), 281; - glacial period, 282; - view of canted, Cordillera Vilcapampa (ill.), opp. p. 280 - -Snowstorm, 170 - -Soiroccocha, 64, 72, 214; - view (ill.), opp. p. 154 - -Solimana, 4, 202, 317; - glaciation, 307 - -Soray, 64 - -Sotospampa, 243 - -South Pacific Ocean, 125 - -Spanish Conquest, 62, 63, 77 - -Spruce (botanist), 153 - -Steinmann, 249, 276 - -Streams, Coast Range, 145-147; - physiography, 192; - _see also_ Water - -Structure. _See_ Rocks - -Stübel, 209 - -Sucre, 93 - -Sugar, 73, 74, 75, 76, 82-83, 92 - -Sullana, 119 - -Survey methods employed in topographic sheets, 315 - - -Tablazo de Ica, 198 - -Tarai. _See_ Urubamba Valley - -Tarapacá, Desert of, 260 - -Tarapoto, 153 - -Taurisma, 317; - geologic sketch map and cross-section, 248 - -Taylor, Capt. A., 126, 128 - -Temperature, Abancay curve (diagr.), opp. p. 180; - Callao (with diagr.), 126-129; - Cochabamba, 176-178; - Cochabamba (diagrs. of ranges), insert opp. p. 178; - curves at various points along 73d meridian, 178-181; - La Joya curves (diagr.), 134; - Mollendo curves (diagr.), 134; - Morococha, 171-173; - Morococha (diagrs. of ranges), insert opp. p. 172; - progressive lowering of saturation, in a desert (diagr.), 127; - Santa Lucia, 161-164; - Santa Lucia (diagrs. of ranges), insert opp. p. 162 - -Tempests, 169-170 - -Terraces, coastal, 225-232; - physical history and physiographic development (with diagrs.), 228-230; - profile at Mollendo (diagr.), 227 - -Terraces, hill slopes (ill.), opp. p. 58 - -Terraces, marine (ill.), opp. p. 226 - -Terraces, valley (ills.), opp. p. 56, opp. p. 57, opp. p. 66; - Huaynacotas (ill.), opp. p. 199 - -_Terral_, 130 - -Tertiary deposits, 249, 251-267; - coastal, 253 - -Ticumpinea, 36, 38, 251 - -Tierra blanca, 254, 266 - -Timber line, 69, 71, 79, 148 - -Timpia, 36, 38, 252; - canoe at mouth (ill.), opp. p. 19 - -Titicaca, 161, 176, 195, 321 - -Titicaca basin, 107 - -Titicaca-Poopó basin, 251 - -Tocate. _See_ Abra Tocate - -_Tola_ bush (ill.), opp. p. 6 - -Tono, 36 - -Topographic and climatic cross-section (diagr.), opp. p. 144 - -Topographic and structural section of northeastern border - of Andes (diagr.), 241 - -Topographic map of the Andes between Abancay and the Pacific - Coast at Camaná, insert opp. p. 312 - -Topographic profiles across typical valleys (diagrs.), 189 - -Topographic regions, 121-122; - map, 123 - -Topographic sheets, survey method employed, 315; - list of, with page references, xi - -Topographical outfit, 315 - -Torontoy, 10, 70, 71, 72, 82, 158, 220 - -Torontoy Canyon, 272, opp. p. 3 (ill.); - cliff (ill.), opp. p. 10 - -Trail (mountain-side) (ill.), opp. p. 78 - -Transportation, 73-74, 93, 152; - rains and, 142 - -Trees, 150; - _see also_ Forests - -_Tucapelle_ (ship), 117 - -Tucker, H. L., ix - -Tumbez, 119 - -Tunari peaks, 276 - - -Ucayali, 42, 44 - -Uplift, recent, 190 - -Upper Carboniferous fossils, 322 - -Urubamba, 1, 41, 42, 62, 187; - village, 70, 73 - -Urubamba River, 72; - fossils, 322; - physiographic observations, 252-253; - rapids and canyons, 8-21; - shelter hut (ill.), opp. p. 11 - -Urubamba Valley, 72, 153, 238; - alluvial fans, 270; - alluvial fill, 272-273; - below Paltaybamba (ill.), opp. p. 74; - canyon walls (ill.), opp. p. 218; - dissected alluvial fans (sketch), 271; - floor from Tarai (ill.), opp. p. 70; - from ice to sugar cane (ill.), opp. p. 3; - geologic sketch map of the lower, 237; - line of unconformity of geologic structure (ill.), opp. p. 250; - rocks, 250; - rocks, succession (diagr.), 249; - sketch map, 9; - slopes and alluvial deposits between Ollantaytambo and Torontoy - (ill.), opp. p. 269; - temperature curves (diagrs.), 178-179; - terraced valley slopes and floor (ill.), opp. p. 66; - vegetation, distribution (ill.), opp. p. 79; - view below Santa Ana (ill.), opp. p. 155; - wheat and bread, 71 - - -Valdivia, Señor, 161 - -Vallenar, 49 - -Valley climates in canyoned region (diagr.), 59 - -Valley planters. _See_ Planters - -Valley profiles, abnormal, 305-313 - -Valleys, eastern; - _see_ Border valleys of the Eastern Andes; - _see also_ Dry valleys, Inter-Andean valleys; - topographic profiles across, typical in Southern Peru (diagrs.), 189 - -Vegetation, 141; - belts (map), 123; - distribution in Urubamba Valley (ill.), opp. p. 79; - shrubbery, mixed with grass (ill.), opp. p. 154; - Tocate pass (ill.), opp. p. 19; - _see also_ Forests - -Vicuña, 54 - -Vilcabamba, 66; - rounded slopes (ill.), opp. p. 72 - -Vilcabamba pueblo, 211, 277, 296 - -Vilcabamba Valley, 189 - -Vilcanota knot, 276 - -Vilcanota Valley, alluvial fill, 272 - -Vilcapampa, Cordillera, 15, 16, 22, 51, 53, 64, 66, 67, 197, 204-224, 233; - batholith and topographic effects, 215-224; - canted snowline (ill.), opp. p. 280; - climatic barrier, 73; - composite geologic section (diagr.), 215; - glacial features, 204-214; - glaciers, 304; - highest pass, crossing (ill.), opp. p. 7; - regional diagram, 65; - regional diagram of the eastern aspect, 68; - schrundline, 302; - snow movement, 287-289; - snow fields on summit (ill.), opp. p. 268; - snow peaks (ill.), opp. p. 72; - snowline, 277, 279; - southwestern aspect (ill.), opp. p. 205; - summit view (ill.), opp. p. 205 - -Vilcapampa Province, 77 - -Vilcapampa Valley, bowldery fill, 269 - -Vilque, 176 - -Violle, 309 - -_Virazon_, 130 - -Vitor, Pampa de, 114, 318 - -Vitor River, 92, 117, 226, 266, 267 - -Volcanic country, 199 - -Volcanic flows, geologic sketch, 244 - -Volcanoes, glacial erosion, 311; - post-glacial, 306-307; - recessed southern slopes (ill.), opp. p. 287; - snowline, 281; - typical form, 310; - views (ills.), opp. p. 204 - -Von Boeck, 176 - -Vulcanism, 199; - _see also_ Volcanoes - - -Ward, R. De C., 126, 143 - -Water, 59, 60, 116, 139; - projected canal from Atlantic to Pacific slope of the - Maritime Cordillera (diagr.), 118; - streams of coastal desert, intermittent and perennial, - diagrams of depth, 119 - -Water skippers, 17 - -Watkins, Mr., 317, 318 - -Weather. _See_ Meteorological records - -Western Andes, 199-203 - -Whymper, 205 - -Wind belts, 122; - map, 123 - -Wind roses, Callao (diagrs.), 128; - Caraveli (diagrs.), 136; - Iquique (diagrs.), 131; - La Joya (diagrs.), 135; - Machu Picchu (diagrs.), 159; - Mollendo (diagrs.), 129; - Santa Lucia (diagrs.), 167; - summer and winter of 1911-1913 (diagrs.), 130 - -Winds, 114, 116; - directions at Machu Picchu, 158-159; - geologic action, 262-267; - prevailing, 125; - Santa Lucia (with diagrs.), 166-168; - trade, 122, 124; - sea-breeze, 129-132 - -Wine, 116, 117 - -Wolf, 205 - - -Yanahuara pass, 170 - -Yanatili, 41, 42, 44; - slopes at junction with Urubamba River (ill.), opp. p. 79 - -_Yareta_ (ill.), opp. p. 6 - -Yavero, 30, 31, 36, 38, 42, 179; - temperature curve (diagr.), 178 - -Yavero (Paucartambo) River, rubber station (ill.), opp. p. 24 - -Yuca, growing (ill.), opp. p. 75 - -Yunguyo, 176 - -Yuyato, 36, 38 - - * * * * * - -FOOTNOTES: - -[1] For all locations mentioned see maps accompanying the text or -Appendix C. - -[2] The Cashibos of the Pachitea are the tribe for whom the Piros -besought Herndon to produce "some great and infectious disease" which -could be carried up the river and let loose amongst them (Herndon, -Exploration of the Valley of the Amazon, Washington. 1854, Vol. 1, p. -196). This would-be artfulness suggests itself as something of a match -against the cunning of the Cashibos whom rumor reports to imitate the -sounds of the forest animals with such skill as to betray into their -hands the hunters of other tribes (see von Tschudi, Travels in Peru -During the Years 1838-1842, translated from the German by Thomasina -Ross, New York, 1849, p. 404). - -[3] The early chronicles contain several references to Antisuyu and the -Antis. Garcilaso de la Vega's description of the Inca conquests in -Antisuyu are well known (Royal Commentaries of the Yncas, Book 4, -Chapters 16 and 17, Hakluyt Soc. Publs., 1st Ser., No. 41, 1869 and Book -7, Chapters 13 and 14, No. 45, 1871). Salcamayhua who also chronicles -these conquests relates a legend concerning the tribute payers of the -eastern valleys. On one occasion, he says, three hundred Antis came -laden with gold from Opatari. Their arrival at Cuzco was coincident with -a killing frost that ruined all the crops of the basin whence the three -hundred fortunates were ordered with their gold to the top of the high -hill of Pachatucsa (Pachatusun) and there buried with it (An Account of -the Antiquities of Peru, Hakluyt Soc. Publs., 1st Ser., No. 48, 1873). - -[4] Notice of a Journey to the Northward and also to the Northeastward -of Cuzco. Royal Geog. Soc. Journ., Vol. 6, 1836, pp. 174-186. - -[5] Walle states (Le Pérou Economique, Paris, 1907, p. 297) that the -Conibos, a tribe of the Ucayali, make annual _correrias_ or raids during -the months of July, August, and September, that is during the season of -low water. Over seven hundred canoes are said to participate and the -captives secured are sold to rubber exploiters, who, indeed, frequently -aid in the organization of the raids. - -[6] Distances are not taken from the map but from the trail. - -[7] Compare with Raimondi's description of Quiches on the left bank of -the Marañon at an elevation of 9,885 feet (3,013 m.): "the few small -springs scarcely suffice for the little patches of alfalfa and other -sowings have to depend on the precarious rains.... Every drop of water -is carefully guarded and from each spring a series of well-like basins -descending in staircase fashion make the most of the scant supply." (El -Departamento de Ancachs, Lima, 1873.) - -[8] Daily Cons. and Trade Report, June 10, 1914, No. 135, and Commerce -Reports, March 20, 1916, No. 66. - -[9] Reference to the figures in this chapter will show great variation -in the level of the timber line depending upon insolation as controlled -by slope exposure and upon moisture directly as controlled largely by -exposure to winds. In some places these controls counteract each other; -in other places they promote each other's effects. The topographic and -climatic cross-sections and regional diagrams elsewhere in this book -also emphasize the patchiness of much of the woodland and scrub, some -noteworthy examples occurring in the chapter on the Eastern Andes. Two -of the most remarkable cases are the patch of woodland at 14,500 feet -(4,420 m.) just under the hanging glacier of Soiroccocha, and the other -the quenigo scrub on the lava plateau above Chuquibamba at 13,000 feet -(3,960 m.). The strong compression of climatic zones in the Urubamba -Valley below Santa Ana brings into sharp contrast the grassy ridge -slopes facing the sun and the forested slopes that have a high -proportion of shade. Fig. 54 represents the general distribution but the -details are far more complicated. See also Figs. 53A and 53B. (See -Coropuna Quadrangle.) - -[10] Commenting on the excellence of the cacao of the montaña of the -Urubamba von Tschudi remarked (op. cit., p. 37) that the long land -transport prevented its use in Lima where the product on the market is -that imported from Guayaquil. - -[11] The inadequacy of the labor supply was a serious obstacle in the -early days as well as now. In the documents pertaining to the "Obispados -y Audiencia del Cuzco" (Vol. 11, p. 349 of the "Juicio de Limites entre -el Perú y Bolivia, Prueba Peruana presentada al Gobierno de la República -Argentina por Victor M. Maurtua," Barcelona, 1900) we find the report -that the natives of the curacy of Ollantaytambo who came down from the -hills to Huadquiña to hear mass were detained and compelled to give a -day's service on the valley plantations under pain of chastisement. - -[12] The Spanish occupation of the eastern valleys was early and -extensive. Immediately after the capture of the young Inca Tupac Amaru -and the final subjugation of the province of Vilcapampa colonists -started the cultivation of coca and cane. Development of the main -Urubamba Valley and tributary valleys proceeded at a good rate: so also -did their troubles. Baltasar de Ocampo writing in 1610 (Account of the -Province of Vilcapampa, Hakluyt Soc. Publs., Ser. 2, Vol. 22, 1907, pp. -203-247) relates the occurrence of a general uprising of the negroes -employed on the sugar plantations of the region. But the peace and -prosperity of every place on the eastern frontier was unstable and quite -generally the later eighteenth and earlier nineteenth centuries saw a -retreat of the border of civilization. The native rebellion of the -mid-eighteenth century in the montaña of Chanchamayo caused entire -abandonment of a previously flourishing area. When Raimondi wrote in -1885 (La Montaña de Chanchamayo, Lima, 1885) some of the ancient -hacienda sites were still occupied by savages. In the Paucartambo -valleys, settlement began by the end of the sixteenth century and at the -beginning of the nineteenth before their complete desolation by the -savages they were highly prosperous. Paucartambo town, itself, once -important for its commerce in coca is now in a sadly decadent condition. - -[13] Notice of a Journey to the Northward and also to the Eastward of -Cuzco, and among the Chunchos Indians, in July, 1835. Journ. Royal Geog. -Soc., Vol. 6, 1836, pp. 174-186. - -[14] Bol. Soc. Geog. de Lima, Vol. 8, 1898, p. 45. - -[15] Marcoy who traveled in Peru in the middle of the last century was -greatly impressed by the sympathetic changes of aspect and topography -and vegetation in the eastern valleys. He thus describes a sudden change -of scene in the Occobamba valley: "... the trees had disappeared, the -birds had taken wing, and great sandy spaces, covered with the latest -deposits of the river, alternated with stretches of yellow grass and -masses of rock half-buried in the ground." (Travels in South America, -translated by Elihu Rich, 2 vols. New York, 1875, Vol. 1, p. 326.) - -[16] According to the latest information (August, 1916) of the Bolivia -Railway Co., trains are running from Oruro to Buen Retiro, 35 km. from -Cochabamba. Thence connection with Cochabamba is made by a tram-line -operated by the Electric Light and Power Co. of that city. The Bulletin -of the Pan-American Union for July, 1916, also reports the proposed -introduction of an automobile service for conveyance of freight and -passengers. - -[17] During his travels Raimondi collected many instances of the -isolation and conservatism of the plateau Indian: thus there is the -village of Pampacolca near Coropuna, whose inhabitants until recently -carried their idols of clay to the slopes of the great white mountain -and worshiped them there with the ritual of Inca days (El Perú, Lima, -1874, Vol. 1). - -[18] Raimondi (op. cit., p. 109) has a characteristic description of the -"Camino del Peñon" in the department of La Libertad: "... the ground -seems to disappear from one's feet; one is standing on an elevated -balcony looking down more than 6,000 feet to the valley ... the road -which descends the steep scarp is a masterpiece." - -[19] Figs. 67 and 68 are from Bol. de Minas del Perú, 1906, No. 37, pp. -82 and 84 respectively. - -[20] The Boletín de Minas del Peru, No. 34, 1905, contains a graphic -representation of the régime of the Rio Chili at Arequipa for the years -1901-1905. - -[21] Hann (Handbook of Climatology, translated by R. De C. Ward, New -York, 1903) indicates a contributory cause in the upwelling of cold -water along the coast caused by the steady westerly drift of the -equatorial current. - -[22] This is the elevation obtained by the Peruvian Expedition. -Raimondi's figure (1,832 m.) is higher. - -[23] According to Ward's observations the base of the cloud belt -averages between 2,000 and 3,000 feet above sea level (Climatic Notes -Made During a Voyage Around South America, Journ. of School Geogr., Vol. -2, 1898). On the south Peruvian coast, specifically at Mollendo, -Middendorf found the cloud belt beginning about 1,000 feet and extending -upwards to elevations of 3,000 to 4,000 feet. At Lima the clouds descend -to lower levels (El Clima de Lima, Bol. Soc. Geogr. de Lima, Vol. 15, -1904). In the third edition of his Süd und Mittelamerika (Leipzig and -Vienna, 1914) Sievers says that at Lima in the winter the cloud on the -coast does not exceed an elevation of 450 m. (1,500 feet) while on the -hills it lies at elevations between 300 and 700 m. (1,000 and 2,300 -feet). - -[24] In most of the coast towns the ford or ferry is an important -institution and the _chimbadores_ or _baleadores_ as they are called are -expert at their trade: they know the régime of the rivers to a nicety. -Several settlements owe their origin to the exigencies of -transportation, permanent and periodic; thus before the development of -its irrigation system Camaná, according to General Miller (Memoirs, -London, 1829, Vol. 2, p. 27), was a hamlet of some 30 people who gained -their livelihood through ferrying freight and passengers across the -Majes River. - -[25] A dry pocket in the Huallaga basin between 6° and 7° S. is -described by Spruce (Notes of a Botanist on the Amazon and Andes, 2 -vols., London, 1908). Tarapoto at an elevation of 1,500 feet above sea -level, encircled by hills rising 2,000 to 3,000 feet higher, rarely -experiences heavy rain though rain falls frequently on the hills. - -[26] Speaking of Cómas situated at the headwaters of a source of the -Perene amidst a multitude of _quebradas_ Raimondi (op. cit., p. 109) -says it "might properly be called the town of the clouds, for there is -not a day during the year, at any rate towards the evening, when the -town is not enveloped in a mist sufficient to hide everything from -view." - -[27] Observer: E. C. Erdis of the 1912 and 1914-15 Expeditions. - -[28] Percentages given because the number of observations varies. - -[29] Observer: Señor Valdivia. For location of Santa Lucia see Fig. 66. - -[30] Observations began on May 12. - -[31] For the first half of the month only; no record for the second -half. - -[32] Boletín de la Sociedad Geográfica de Lima, Vol. 13, pp. 473-480, -Lima, 1903. - -[33] Boletín del Cuerpo de Ingenieros de Minas del Perú, No. 34, Lima, -1905, also reproduced in No. 45, 1906. - -[34] The record is copied literally without regard to the absurdity of -the second and third decimal places. - -[35] In the Eastern Cordillera, however, snowstorms may be more serious. -Prior to the construction of the Urubamba Valley Road by the Peruvian -government the three main routes to the Santa Ana portion of the valley -proceeded via the passes of Salcantay, Panticalla, and Yanahuara -respectively. Frequently all are completely snow-blocked and fatalities -are by no means unknown. In 1864 for instance nine persons succumbed on -the Yanahuara pass (Raimondi, op. cit., p. 109). - -[36] Boletín de la Sociedad Geográfica de Lima, Vol. 27, 1911; Vol. 28, -1912. - -[37] Boletín del Cuerpo de Ingenieros de Minas del Perú, No. 65, 1908. - -[38] This figure is approximate: some days' records were missing from -the first three months of the year and the total was estimated on a -proportional basis. - -[39] Christoval de Molina, The Fables and Rites of the Yncas, Hakluyt -Soc. Publs., 1st Ser., No. 48, 1873. - -[40] See Meteorologische Zeitschrift, Vol. 5, p. 195, 1888. Also cited -by J. Hann in Handbuch der Climatologie, Vol. 2, Stuttgart, 1897; W. -Sievers, Süd und Mittelamerika, Leipzig and Vienna, 1914, p. 334. - -[41] The Physiography of the Central Andes, Am. Journ. Sci., Vol. 40, -1909, pp. 197-217 and 373-402. - -[42] Results of an Expedition to the Central Andes, Bull. Am. Geog. -Soc., Vol. 46, 1914. Figs. 28 and 29. - -[43] The Physiography of the Central Andes, by Isaiah Bowman; Am. Journ. -Sci., Vol. 28, 1909, pp. 197-217 and 373-402. See especially, _ibid._, -Fig. 11, p. 216. - -[44] Travels Amongst the Great Andes of the Equator, 1892. - -[45] Geografía y Geología del Ecuador, 1892. - -[46] Das Hochgebirge der Republik Ecuador, Vol. 2, 2 Ost-Cordillera, -1902, p. 162. - -[47] Contributions to the Geology of British East Africa; Pt. 1, The -Glacial Geology of Mount Kenia, Quart. Journ. Geol. Soc., Vol. 50, 1894, -p. 523. - -[48] See especially A. Penck (Penck and Brückner), Die Alpen im -Eiszeitalter, 1909, Vol. 1, p. 6, and I. C. Russell, Glaciers of Mount -Rainier, 18th Ann. Rep't, U. S. Geol. Surv., 1890-97, Sect. 2, pp. -384-385. - -[49] Die Sierra Nevada de Santa Marta und die Sierra de Perijá, -Zeitschrift der Gesellschaft für Erdkunde zu Berlin, Vol. 23, 1888, pp. -1-158. - -[50] For a list of the fossils that form the basis of the age -determinations in this chapter see Appendix B. - -[51] Eastern Bolivia and the Gran Chaco, Proc. Royal Geogr. Soc., Vol. -3, 1881, pp. 401-420. - -[52] The Physiography of the Central Andes, Am. Journ. Sci., Vol. 28, -1909, p. 395. - -[53] See paper by H. S. Palmer, my assistant on the Expedition to the -Central Andes, 1913, entitled: Geological Notes on the Andes of -Northwestern Argentina, Am. Journ. Sci., Vol. 38, 1914, pp. 309-330. - -[54] The best photograph of this condition which I have yet seen is in -W. Sievers, Südund Mittelamerika, second ed., 1914, Plate 15, p. 358. - -[55] Paschinger, Die Schneegrenze in verschiedenen Klimaten. Peter. -Mitt. Erganz'heft, Nr. 173. 1912, pp. 92-93. - -[56] Hann, Handbook of Climatology, Part 1, trans. by Ward, 1903, p. -232. - -[57] S. I. Bailey, Peruvian Meteorology, 1888-1890. Ann. Astron. Observ. -of Harvard Coll., Vol. 39, Pt. I, 1899, pp. 1-3. - -[58] F. E. Matthes, Glacial Sculpture of the Bighorn Mountains, Wyoming, -Twentieth Ann. Rept. U. S. Geol. Surv., 1899-1900, Pt. 2, p. 181. - -[59] Idem, p. 190. - -[60] W. H. Hobbs, Characteristics of Existing Glaciers, 1911, p. 22. - -[61] Op. cit., p. 286. Reference on p. 190. - -[62] Corrosion of Gravity Streams with Application of the Ice Flood -Hypothesis, Journ. and Proc. of the Royal Society of N. S. Wales, Vol. -43, 1909, p. 286. - -[63] G. K. Gilbert, Systematic Asymmetry of Crest Lines in the High -Sierra of California. Jour. Geol., Vol. 12, 1904, p. 582. - -[64] Op. cit., p. 300; reference on p. 582. - -[65] Op. cit., p. 300; see pp. 579-588 and Fig. 8. - -[66] The observation at Camaná checks very closely with a Peruvian -observation the value of which is S. 16° 37' 00". - - - - - - -End of Project Gutenberg's The Andes of Southern Peru, by Isaiah Bowman - -*** END OF THIS PROJECT GUTENBERG EBOOK THE ANDES OF SOUTHERN PERU *** - -***** This file should be named 42860-8.txt or 42860-8.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/4/2/8/6/42860/ - -Produced by Chuck Greif, The University of Florida Digital -Collections and the Online Distributed Proofreading Team -at http://www.pgdp.net - - -Updated editions will replace the previous one--the old editions -will be renamed. - -Creating the works from public domain print editions means that no -one owns a United States copyright in these works, so the Foundation -(and you!) can copy and distribute it in the United States without -permission and without paying copyright royalties. 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You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org/license - - -Title: The Andes of Southern Peru - Geographical Reconnaissance along the Seventy-Third Meridian - -Author: Isaiah Bowman - -Release Date: June 2, 2013 [EBook #42860] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK THE ANDES OF SOUTHERN PERU *** - - - - -Produced by Chuck Greif, The University of Florida Digital -Collections and the Online Distributed Proofreading Team -at http://www.pgdp.net - - - - - -Transcriber's note: The etext attempts to replicate the printed book as -closely as possible. Obvious errors in spelling and punctuation have -been corrected. The spellings of names, places and Spanish words used by -the author have not been corrected or modernized by the etext -transcriber. The footnotes have been moved to the end of the text body. -The images have been moved from the middle of a paragraph to the closest -paragraph break for ease of reading. - - [Illustration] - - - - - THE ANDES OF SOUTHERN - PERU - - GEOGRAPHICAL RECONNAISSANCE ALONG THE - SEVENTY-THIRD MERIDIAN - - BY - - ISAIAH BOWMAN - Director of the American Geographical Society - - [Illustration: colophon] - - PUBLISHED FOR - THE AMERICAN GEOGRAPHICAL SOCIETY - OF NEW YORK - - BY - - HENRY HOLT AND COMPANY - - 1916 - - LATIN - AMERICA - - COPYRIGHT, 1918 - - BY - - HENRY HOLT AND COMPANY - - THE QUINN & BODEN CO. PRESS - RAHWAY, N.J. - - TO - - C. G. B. - - - - -PREFACE - - -The geographic work of the Yale Peruvian Expedition of 1911 was -essentially a reconnaissance of the Peruvian Andes along the 73rd -meridian. The route led from the tropical plains of the lower Urubamba -southward over lofty snow-covered passes to the desert coast at Camaná. -The strong climatic and topographic contrasts and the varied human life -which the region contains are of geographic interest chiefly because -they present so many and such clear cases of environmental control -within short distances. Though we speak of “isolated†mountain -communities in the Andes, it is only in a relative sense. The extreme -isolation felt in some of the world’s great deserts is here unknown. It -is therefore all the more remarkable when we come upon differences of -customs and character in Peru to find them strongly developed in spite -of the small distances that separate unlike groups of people. - -My division of the Expedition undertook to make a contour map of the -two-hundred-mile stretch of mountain country between Abancay and the -Pacific coast, and a great deal of detailed geographic and physiographic -work had to be sacrificed to insure the completion of the survey. Camp -sites, forage, water, and, above all, strong beasts for the -topographer’s difficult and excessively lofty stations brought daily -problems that were always serious and sometimes critical. I was so -deeply interested in the progress of the topographic map that whenever -it came to a choice of plans the map and not the geography was first -considered. The effect upon my work was to distribute it with little -regard to the demands of the problems, but I cannot regret this in view -of the great value of the maps. Mr. Kai Hendriksen did splendid work in -putting through two hundred miles of plane-tabling in two months under -conditions of extreme difficulty. Many of his triangulation stations -ranged in elevation from 14,000 to nearly 18,000 feet, and the cold and -storms--especially the hailstorms of mid-afternoon--were at times most -severe. - -It is also a pleasure to say that Mr. Paul Baxter Lanius, my assistant -on the lower Urubamba journey, rendered an invaluable service in -securing continuous weather records at Yavero and elsewhere, and in -getting food and men to the river party at a critical time. Dr. W. G. -Erving, surgeon of the Expedition, accompanied me on a canoe journey -through the lower gorge of the Urubamba between Rosalina and the mouth -of the Timpia, and again by pack train from Santa Ana to Cotahuasi. For -a time he assisted the topographer. It is due to his prompt surgical -assistance to various members of the party that the field work was -uninterrupted. He was especially useful when two of our river Indians -from Pongo de Mainique were accidentally shot. I have since been -informed by their _patrón_ that they were at work within a few months. - -It is difficult to express the gratitude I feel toward Professor Hiram -Bingham, Director of the Expedition, first for the executive care he -displayed in the organization of the expedition’s plans, which left the -various members largely care-free, and second, for generously supplying -the time of various assistants in the preparation of results. I have -enjoyed so many facilities for the completion of the work that at least -a year’s time has been saved thereby. Professor Bingham’s enthusiasm for -pioneer field work was in the highest degree stimulating to every member -of the party. Furthermore, it led to a determination to complete at all -hazards the original plans. - -Finally, I wish gratefully to acknowledge the expert assistance of Miss -Gladys M. Wrigley, of the editorial staff of the American Geographical -Society, who prepared the climatic tables, many of the miscellaneous -data related thereto, and all of the curves in Chapter X. Miss Wrigley -also assisted in the revision of Chapters IX and X and in the correction -of the proof. Her eager and in the highest degree faithful assistance in -these tasks bespeaks a true scientific spirit. - -ISAIAH BOWMAN. - - -SPECIAL ACKNOWLEDGMENTS FOR ILLUSTRATIONS - -Fig. 28. Photograph by H. L. Tucker, Engineer, Yale Peruvian Expedition -of 1911. - -Fig. 43. Photograph by H. L. Tucker. - -Fig. 44. Photograph by Professor Hiram Bingham. - -Figs. 136, 139, 140. Data for hachured sketch maps, chiefly from -topographic sheets by A. H. Bumstead, Topographer to Professor Bingham’s -Peruvian Expeditions of 1912 and 1914. - - - - -CONTENTS - - -PART I - -HUMAN GEOGRAPHY - -CHAPTER PAGE - -I. THE REGIONS OF PERU 1 - -II. THE RAPIDS AND CANYONS OF THE URUBAMBA 8 - -III. THE RUBBER FORESTS 22 - -IV. THE FOREST INDIANS 36 - -V. THE COUNTRY OF THE SHEPHERDS 46 - -VI. THE BORDER VALLEYS OF THE EASTERN ANDES 68 - -VII. THE GEOGRAPHIC BASIS OF REVOLUTIONS AND OF HUMAN -CHARACTER IN THE PERUVIAN ANDES 88 - -VIII. THE COASTAL DESERT 110 - -IX. CLIMATOLOGY OF THE PERUVIAN ANDES 121 - -X. METEOROLOGICAL RECORDS FROM THE PERUVIAN ANDES 157 - - -PART II - -PHYSIOGRAPHY OF THE PERUVIAN ANDES - -XI. THE PERUVIAN LANDSCAPE 183 - -XII. THE WESTERN ANDES: THE MARITIME CORDILLERA OR CORDILLERA -OCCIDENTAL 199 - -XIII. THE EASTERN ANDES: THE CORDILLERA VILCAPAMPA 204 - -XIV. THE COASTAL TERRACES 225 - -XV. PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 233 - -XVI. GLACIAL FEATURES 274 - - -APPENDIX A. SURVEY METHODS EMPLOYED IN THE CONSTRUCTION OF -THE SEVEN ACCOMPANYING TOPOGRAPHIC SHEETS 315 - -APPENDIX B. FOSSIL DETERMINATIONS 321 - -APPENDIX C. KEY TO PLACE NAMES 324 - -INDEX 327 - - -TOPOGRAPHIC SHEETS - -Camaná Quadrangle 114 - -Aplao " 120 - -Coropuna " 188 - -Cotahuasi " 192 - -La Cumbre " 202 - -Antabamba " 282 - -Lambrama " - - - - -PART I - -HUMAN GEOGRAPHY - - - - -CHAPTER I - -THE REGIONS OF PERU - - -Let four Peruvians begin this book by telling what manner of country -they live in. Their ideas are provincial and they have a fondness for -exaggerated description: but, for all that, they will reveal much that -is true because they will at least reveal themselves. Their opinions -reflect both the spirit of the toiler on the land and the outlook of the -merchant in the town in relation to geography and national problems. -Their names do not matter; let them stand for the four human regions of -Peru, for they are in many respects typical men. - - -THE FOREST DWELLER - -One of them I met at a rubber station on the lower Urubamba River.[1] He -helped secure my canoe, escorted me hospitably to his hut, set food and -drink before me, and talked of the tropical forest, the rubber business, -the Indians, the rivers, and the trails. In his opinion Peru was a land -of great forest resources. Moreover, the fertile plains along the river -margins might become the sites of rich plantations. The rivers had many -fish and his garden needed only a little cultivation to produce an -abundance of food. Fruit trees grew on every hand. He had recently -married the daughter of an Indian chief. - -Formerly he had been a missionary at a rubber station on the Madre de -Dios, where the life was hard and narrow, and he doubted if there were -any real converts. Himself the son of an Englishman and a Chilean woman, -he found, so he said, that a missionary’s life in the rubber forest was -intolerable for more than a few years. Yet he had no fault to find with -the religious system of which he had once formed a part; in fact he had -still a certain curious mixed loyalty to it. Before I left he gave me a -photograph of himself and said with little pride and more sadness that -perhaps I would remember him as a man that had done some good in the -world along with much that might have been better. - -We shall understand our interpreter better if we know who his associates -were. He lived with a Frenchman who had spent several years in Africa as -a soldier in the “Foreign Legion.†If you do not know what that means, -you have yet all the pleasure of an interesting discovery. The Frenchman -had reached the station the year before quite destitute and clad only in -a shirt and a pair of trousers. A day’s journey north lived a young -half-breed--son of a drunken father and a Machiganga woman, who cheated -me so badly when I engaged Indian paddlers that I should almost have -preferred that he had robbed me. Yet in a sense he had my life in his -hands and I submitted. A German and a native Peruvian ran a rubber -station on a tributary two days’ journey from the first. It will be -observed that the company was mixed. They were all Peruvians, but of a -sort not found in such relative abundance elsewhere. The defeated and -the outcast, as well as the pioneer, go down eventually to the hot -forested lands where men are forgotten. - -While he saw gold in every square mile of his forested region, my -clerical friend saw misery also. The brutal treatment of the Indians by -the whites of the Madre de Dios country he could speak of only as a man -reviving a painful memory. The Indians at the station loved him -devotedly. There was only justice and kindness in all his dealings. -Because he had large interests to look after, he knew all the members of -the tribe, and his word was law in no hackneyed sense. A kindlier man -never lived in the rubber forest. His influence as a high-souled man of -business was vastly greater than as a missionary in this frontier -society. He could daily illustrate by practical example what he had -formerly been able only to preach. - -[Illustration: Fig. 1--Tropical vegetation, clearing on the river bank -and rubber station at Pongo de Mainique. The pronounced scarp on the -northeastern border of the Andes is seen in the right background.] - -[Illustration: Fig. 2--Pushing a heavy dugout against the current in the -rapids below Pongo de Mainique. The indian boy and his father in the -canoe had been accidentally shot.] - -[Illustration: Fig. 3--From the sugar cane, Urubanba Valley, at Colpani. -On the northeastern border of the Cordillera Vilcapampa looking -upstream. In the extreme background and thirteen sixteens of an inch -from the top of the picture is the sharp peak of Salcantay. Only the -lower end of the more open portion of the Canyon of Torontoy is here -shown. There is a field of sugar cane in the foreground and the valley -trail is shown on the opposite side of the river.] - -He thought the life of the Peruvian cities debasing. The coastal -valleys were small and dry and the men who lived there were crowded and -poor (sic). The plateau was inhabited by Indians little better than -brutes. Surely I could not think that the fine forest Indian was lower -than the so-called civilized Indian of the plateau. There was plenty of -room in the forest; and there was wealth if you knew how to get at it. -Above all you were far from the annoying officials of the government, -and therefore could do much as you pleased so long as you paid your -duties on rubber and did not wantonly kill too many Indians. - -For all his kindly tolerance of men and conditions he yet found fault -with the government. “They†neglected to build roads, to encourage -colonization, and to lower taxes on the forest products, which were -always won at great risk. Nature had done her part well--it was only -government that hindered. Moreover, the forested region was the land of -the future. If Peru was to be a great nation her people would have to -live largely upon the eastern plains. Though others spoke of “going in†-and “coming out†of the rubber country as one might speak of entering -and leaving a dungeon, he always spoke of it as home. Though he now -lived in the wilderness he hoped to see the day when plantations covered -the plains. A greater Peru and the forest were inseparable ideas to him. - - -THE EASTERN VALLEY PLANTER - -My second friend lived in one of the beautiful mountain valleys of the -eastern Andes. We walked through his clean cacao orchards and cane -fields. Like the man in the forest, he believed in the thorough -inefficiency of the government; otherwise why were there no railways for -the cheaper transportation of the valley products, no dams for the -generation of power and the storage of irrigation water, not even roads -for mule carts? Had the government been stable and efficient there would -now be a dense population in the eastern valleys. Revolutions were the -curse of these remote sections of the country. The ne’er-do-wells became -generals. The loafer you dismissed today might demand ten thousand -dollars tomorrow or threaten to destroy your plantation. The government -troops might come to help you, but they were always too late. - -For this one paid most burdensome taxes. Lima profited thereby, not the -valley planters. The coast people were the favored of Peru anyhow. They -had railroads, good steamer service, public improvements at government -expense, and comparatively light taxes. If the government were impartial -the eastern valleys also would have railways and a dense population. Who -could tell? Perhaps the capital city might be here. Certainly it was -better to have Lima here than on the coast where the Chileans might at -any time take it again. The blessings of the valleys were both rich and -manifold. Here was neither a cold plateau nor the hot plains, but -fertile valleys with a vernal climate. - -We talked of much else, but our conversation had always the pioneer -flavor. And though an old man he saw always the future Peru growing -wonderfully rich and powerful as men came to recognize and use the -resources of the eastern valleys. This too was the optimism of the -pioneer. Once started on that subject he grew eloquent. He was -provincial but he was also intensely patriotic. He never missed an -opportunity to impress upon his guests that a great state would arise -when people and rulers at last recognized the wealth of eastern Peru. - - -THE HIGHLAND SHEPHERD - -The people who live in the lofty highlands and mountains of Peru have -several months of real winter weather despite their tropical latitude. -In the midst of a snowstorm in the Maritime Cordillera I met a solitary -traveler bound for Cotahuasi on the floor of a deep canyon a day’s -journey toward the east. It was noon and we halted our pack trains in -the lee of a huge rock shelter to escape the bitter wind that blew down -from the snow-clad peaks of Solimana. Men who follow the same trails are -fraternal. In a moment we had food from our saddle-bags spread on the -snow under the corner of a _poncho_ and had exchanged the best in each -other’s collection as naturally as friends exchange greetings. By the -time I had told him whence and why in response to his inevitable -questions we had finished the food and had gathered a heap of _tola_ -bushes for a fire. The _arriero_ (muleteer) brought water from a spring -in the hollow below us. Though the snow thickened, the wind fell. We -were comfortable, even at 16,000 feet, and called the place “The -Salamanca Club.†Then I questioned him, and this is what he said: - -“I live in the deep valley of Cotahuasi, but my lands lie chiefly up -here on the plateau. My family has held title to this _puna_ ever since -the Wars of Liberation, except for a few years after one of our early -revolutions. I travel about a great deal looking after my flocks. Only -Indians live up here. Away off yonder beyond that dark gorge is a group -of their huts, and on the bright days of summer you may see their sheep, -llamas, and alpacas up here, for on the floors of the watered valleys -that girdle these volcanoes there are more tender grasses than grow on -this _despoblado_. I give them corn and barley from my irrigated fields -in the valley; they give me wool and meat. The alpaca wool is most -valuable. It is hard to get, for the alpaca requires short grasses and -plenty of water, and you see there is only coarse tufted ichu grass -about us, and there are no streams. It is all right for llamas, but -alpacas require better forage. - -“No one can imagine the poverty and ignorance of these mountain -shepherds. They are filthier than beasts. I have to watch them -constantly or they would sell parts of the flocks, which do not belong -to them, or try to exchange the valuable alpaca wool for coca leaves in -distant towns. They are frequently drunk.†- -“But where do they get the drink?†I asked. “And what do you pay them?†- -“Oh, the drink is chiefly imported alcohol, and also _chicha_ made from -corn. They insist on having it, and do better when I bring them a little -now and then. They get much more from the dealers in the towns. As for -pay, I do not pay them anything in money except when they bring meat to -the valley. Then I give them a few _reales_ apiece for the sheep and a -little more for the llamas. The flocks all belong to me really, but of -course the poor Indian must have a little money. Besides, I let him have -a part of the yearly increase. It is not much, but he has always lived -this way and I suppose that he is contented after a fashion.†- -Then he became eager to tell what wealth the mountains contained in soil -and climate if only the right grasses were introduced by the government. - -“Here, before us, are vast _punas_ almost without habitations. If the -officials would bring in hardy Siberian grasses these lava-covered -plateaus might be carpeted with pasture. There would be villages here -and there. The native Indians easily stand the altitude. This whole -Cordillera might have ten times as many people. Why does the government -bother about concessions in the rubber forests and roads to the eastern -valleys when there are these vast tracts only requiring new seeds to -develop into rich pastures? The government could thus greatly increase -its revenues because there is a heavy tax on exported wool.†- -Thus he talked about the bleak Cordillera until we forgot the pounding -of our hearts and our frequent gasps for breath on account of the -altitude. His rosy picture of a well-populated highland seemed to bring -us down nearer sea level where normal folks lived. To the Indians the -altitude is nothing. It has an effect, but it is slight; at any rate -they manage to reproduce their kind at elevations that would kill a -white mother. If alcohol were abolished and better grasses introduced, -these lofty pastures might indeed support a much larger population. The -sheep pastures of the world are rapidly disappearing before the march of -the farmer. Here, well above the limit of cultivation, is a permanent -range, one of the great as well as permanent assets of Peru. - - -THE COASTAL PLANTER - -The man from the deep Majes Valley in the coastal desert rode out with -me through cotton fields as rich and clean as those of a Texas -plantation. He was tall, straight-limbed, and clear-eyed--one of the -energetic younger generation, yet with the blood of a proud old family. -We forded the river and rode on through vineyards and fig orchards -loaded with fruit. His manner became deeply earnest as he pictured the -future of Peru, when her people would take advantage of scientific -methods and use labor-saving machinery. He said that the methods now in -use were medieval, and he pointed to a score of concrete illustrations. -Also, here was water running to waste, yet the desert was on either -hand. There should be dams and canals. Every drop of water was needed. -The population of the valley could be easily doubled. - -[Illustration: FIG. 4--Large ground moss--so-called _yareta_--used for -fuel. It occurs in the zone of Alpine vegetation and is best developed -in regions where the snowline is highest. The photograph represents a -typical occurrence between Cotahuasi and Salamanca, elevation 16,000 -feet (4,880 m.). The snowline is here at 17,500 feet (5,333 m.). In the -foreground is the most widely distributed _tola_ bush, also used for -fuel.] - -[Illustration: FIG. 5.--Expedition’s camp near Lamgrama, 15,500 feet -(4,720 m.), after a snowstorm The location is midway in the pasture -zone.] - -[Illustration: FIG. 6--Irrigated Chili Valley on the outskirts of -Arequipa. The lower slopes of El Misti are in the left background. The -_Alto de los Huesos_ or Plateau of Bones lies on the farther side of the -valley.] - -[Illustration: FIG. 7--Crossing the highest pass (Chuquito) in the -Cordillera Vilcapampa, 14,500 feet (4,420 m.). Grazing is here carried -on up to the snowline.] - -Capital was lacking but there was also lacking energy among the people. -Slipshod methods brought them a bare living and they were too easily -contented. Their standards of life should be elevated. Education was -still for the few, and it should be universal. A new spirit of progress -was slowly developing--a more general interest in public affairs, a -desire to advance with the more progressive nations of South -America,--and when it had reached its culmination there would be no -happier land than coastal Peru, already the seat of the densest -populations and the most highly cultivated fields. - - * * * * * - -These four men have portrayed the four great regions of Peru--the -lowland plains, the eastern mountain valleys, the lofty plateaus, and -the valley oases of the coast. This is not all of Peru. The mountain -basins have their own peculiar qualities and the valley heads of the -coastal zone are unlike the lower valleys and the plateau on either -hand. Yet the chief characteristics of the country are set forth with -reasonable fidelity in these individual accounts. Moreover the spirit of -the Peruvians is better shown thereby than their material resources. If -this is not Peru, it is what the Peruvians think is Peru, and to a high -degree a man’s country is what he thinks it is--at least it is little -more to him. - - - - -CHAPTER II - -THE RAPIDS AND CANYONS OF THE URUBAMBA - - -Among the scientifically unexplored regions of Peru there is no other so -alluring to the geographer as the vast forested realm on the eastern -border of the Andes. Thus it happened that within two weeks of our -arrival at Cuzco we followed the northern trail to the great canyon of -the Urubamba (Fig. 8), the gateway to the eastern valleys and the -lowland plains of the Amazon. It is here that the adventurous river, -reënforced by hundreds of mountain-born tributaries, finally cuts its -defiant way through the last of its great topographic barriers. More -than seventy rapids interrupt its course; one of them, at the mouth of -the Sirialo, is at least a half-mile in length, and long before one -reaches its head he hears its roaring from beyond the forest-clad -mountain spurs. - -The great bend of the Urubamba in which the line of rapids occurs is one -of the most curious hydrographic features in Peru. The river suddenly -changes its general northward course and striking south of west flows -nearly fifty miles toward the axis of the mountains, where, turning -almost in a complete circle, it makes a final assault upon the eastern -mountain ranges. Fifty miles farther on it breaks through the long -sharp-crested chain of the Front Range of the Andes in a splendid gorge -more than a half-mile deep, the famous _Pongo de Mainique_ (Fig. 9). - -Our chief object in descending the line of rapids was to study the -canyon of the Urubamba below Rosalina and to make a topographic sketch -map of it. We also wished to know what secrets might be gathered in this -hitherto unexplored stretch of country, what people dwelt along its -banks, and if the vague tales of deserted towns and fugitive tribes had -any basis in fact. - -[Illustration: FIG. 8--Sketch map showing the route of the Yale-Peruvian -Expedition of 1911 down the Urubamba Valley, together with the area of -the main map and the changes in the delineation of the bend of the -Urubamba resulting from the surveys of the Expedition. Based on the -“Mapa que comprende las ultimas exploraciones y estudios verificados -desde 1900 hasta 1906,†1:1,000,000, Bol. Soc. Geogr. Lima, Vol. 25, No. -3, 1909. For details of the trail from Rosalina to Pongo de Mainique see -“Plano de las Secciones y Afluentes del Rio Urubamba: 1902-1904,†scale -1:150,000 by Luis M. Robledo in Bol. Soc. Geogr. Lima, Vol. 25, No. 4, -1909. Only the lower slopes of the long mountain spurs can be seen from -the river; hence only in a few places could observations be made on the -topography of distant ranges. Paced distances of a half mile at -irregular intervals were used for the estimation of longer distances. -Directions were taken by compass corrected for magnetic deviation as -determined on the seventy-third meridian (See Appendix A). The position -of Rosalina on Robledo’s map was taken as a base.] - -We could gather almost no information as to the nature of the river -except from the report of Major Kerbey, an American, who, in 1897, -descended the last twenty miles of the one hundred we proposed to -navigate. He pronounced the journey more hazardous than Major Powell’s -famous descent of the Grand Canyon in 1867--an obvious exaggeration. He -lost his canoe in a treacherous rapid, was deserted by his Indian -guides, and only after a painful march through an all but impassable -jungle was he finally able to escape on an abandoned raft. Less than a -dozen have ventured down since Major Kerbey’s day. A Peruvian mining -engineer descended the river a few years ago, and four Italian traders a -year later floated down in rafts and canoes, losing almost all of their -cargo. For nearly two months they were marooned upon a sand-bar waiting -for the river to subside. At last they succeeded in reaching -Mulanquiato, an Indian settlement and plantation owned by Pereira, near -the entrance to the last canyon. Their attempted passage of the worst -stretch of rapids resulted in the loss of all their rubber cargo, the -work of a year. Among the half dozen others who have made the -journey--Indians and slave traders from down-river rubber posts--there -is no record of a single descent without the loss of at least one canoe. - -To reach the head of canoe navigation we made a two weeks’ muleback -journey north of Cuzco through the steep-walled granite Canyon of -Torontoy, and to the sugar and cacao plantations of the middle Urubamba, -or Santa Ana Valley, where we outfitted. At Echarati, thirty miles -farther on, where the heat becomes more intense and the first patches of -real tropical forest begin, we were obliged to exchange our beasts for -ten fresh animals accustomed to forest work and its privations. Three -days later we pitched our tent on the river bank at Rosalina, the last -outpost of the valley settlements. As we dropped down the steep mountain -slope before striking the river flood plain, we passed two half-naked -Machiganga Indians perched on the limbs of a tree beside the trail, our -first sight of members of a tribe whose territory we had now entered. -Later in the day they crossed the river in a dugout, landed on the -sand-bar above us, and gathered brush for the nightly fire, around which -they lie wrapped in a single shirt woven from the fiber of the wild -cotton. - -[Illustration: FIG. 9--The upper entrance to the Pongo de Mainique, -where the Urubamba crosses the Front Range of the Andes in a splendid -gateway 4,000 feet deep. The river is broken by an almost continuous -line of rapids.] - -[Illustration: FIG. 10--The lower half of a two-thousand-foot cliff, -granite Canyon of Torontoy, Urubamba Valley. The wall is developed -almost entirely along joint planes. It is here that the Urubamba River -crosses the granite axis of the Cordillera Vilcapampa, the easternmost -system of the Andes of southern Peru. Compare also Figs. 144 and 145.] - -[Illustration: FIG. 11--A temporary shelter-hut on a sand-bar near the -great bend of the Urubamba (see map, Fig. 8). The Machiganga Indians use -these cane shelters during the fishing season, when the river is low.] - -[Illustration: FIG. 12--Thirty-foot canoe in a rapid above Pongo de -Mainique.] - -Rosalina is hardly more than a name on the map and a camp site on the -river bank. Some distance back from the left bank of the river is a -sugar plantation, whose owner lives in the cooler mountains, a day’s -journey away; on the right bank is a small clearing planted to sugar -cane and yuca, and on the edge of it is a reed hut sheltering three -inhabitants, the total population of Rosalina. The owner asked our -destination, and to our reply that we should start in a few days for -Pongo de Mainique he offered two serious objections. No one thought of -arranging so difficult a journey in less than a month, for canoe and -Indians were difficult to find, and the river trip was dangerous. -Clearly, to start without the loss of precious time would require -unusual exertion. We immediately despatched an Indian messenger to the -owner of the small hacienda across the river while one of our peons -carried a second note to a priest of great influence among the forest -Indians, Padre Mendoza, then at his other home in the distant mountains. - -The answer of Señor Morales was his appearance in person to offer the -hospitality of his home and to assist us in securing canoe and oarsmen. -To our note the Padre, from his hill-top, sent a polite answer and the -offer of his large canoe if we would but guarantee its return. His -temporary illness prevented a visit to which we had looked forward with -great interest. - -The morning after our arrival I started out on foot in company with our -_arriero_ in search of the Machigangas, who fish and hunt along the -river bank during the dry season and retire to their hill camps when the -heavy rains begin. We soon left the well-beaten trail and, following a -faint woodland path, came to the river bank about a half day’s journey -below Rosalina. There we found a canoe hidden in an overhanging arch of -vines, and crossing the river met an Indian family who gave us further -directions. Their vague signs were but dimly understood and we soon -found ourselves in the midst of a _carrizo_ (reed) swamp filled with -tall bamboo and cane and crossed by a network of interlacing streams. We -followed a faint path only to find ourselves climbing the adjacent -mountain slopes away from our destination. Once again in the swamp we -had literally to cut our way through the thick cane, wade the numberless -brooks, and follow wild animal trails until, late in the day, famished -and thirsty, we came upon a little clearing on a sand-bar, the hut of La -Sama, who knew the Machigangas and their villages. - -After our long day’s work we had fish and yuca, and water to which had -been added a little raw cane sugar. Late at night La Sama returned from -a trip to the Indian villages down river. He brought with him a -half-dozen Machiganga Indians, boys and men, and around the camp fire -that night gave us a dramatic account of his former trip down river. At -one point he leaped to his feet, and with an imaginary pole shifted the -canoe in a swift rapid, turned it aside from imminent wreck, and -shouting at the top of his voice over the roar of the water finally -succeeded in evading what he had made seem certain death in a whirlpool. -We kept a fire going all night long for we slept upon the ground without -a covering, and, strange as it may appear, the cold seemed intense, -though the minimum thermometer registered 59° F. The next morning the -whole party of ten sunned themselves for nearly an hour until the flies -and heat once more drove them to shelter. - -Returning to camp next day by a different route was an experience of -great interest, because of the light it threw on hidden trails known -only to the Indian and his friends. Slave raiders in former years -devastated the native villages and forced the Indian to conceal his -special trails of refuge. At one point we traversed a cliff seventy-five -feet above the river, walking on a narrow ledge no wider than a man’s -foot. At another point the dim trail apparently disappeared, but when we -had climbed hand over hand up the face of the cliff, by hanging vines -and tree roots, we came upon it again. Crossing the river in the canoe -we had used the day before, we shortened the return by wading the swift -Chirumbia waist-deep, and by crawling along a cliff face for nearly an -eighth of a mile. At the steepest point the river had so under-cut the -face that there was no trail at all, and we swung fully fifteen feet -from one ledge to another, on a hanging vine high above the river. - -After two days’ delay we left Rosalina late in the afternoon of August -7. My party included several Machiganga Indians, La Sama, and Dr. W. G. -Erving, surgeon of the expedition. Mr. P. B. Lanius, Moscoso (the -_arriero_), and two peons were to take the pack train as far as possible -toward the rubber station at Pongo de Mainique where preparations were -to be made for our arrival. At the first rapid we learned the method of -our Indian boatmen. It was to run the heavy boat head on into shallow -water at one side of a rapid and in this way “brake†it down stream. -Heavily loaded with six men, 200 pounds of baggage, a dog, and supplies -of yuca and sugar cane our twenty-five foot dugout canoe was as rigid as -a steamer, and we dropped safely down rapid after rapid until long after -dark, and by the light of a glorious tropical moon we beached our craft -in front of La Sama’s hut at the edge of the cane swamp. - -Here for five days we endured a most exasperating delay. La Sama had -promised Indian boatmen and now said none had yet been secured. Each day -Indians were about to arrive, but by nightfall the promise was broken -only to be repeated the following morning. To save our food supply--we -had taken but six days’ provisions--we ate yuca soup and fish and some -parched corn, adding to this only a little from our limited stores. At -last we could wait no longer, even if the map had to be sacrificed to -the work of navigating the canoe. Our determination to leave stirred La -Sama to final action. He secured an assistant named Wilson and embarked -with us, planning to get Indians farther down river or make the journey -himself. - -On August 12, at 4.30 P.M., we entered upon the second stage of the -journey. As we shot down the first long rapid and rounded a wooded bend -the view down river opened up and gave us our first clear notion of the -region we had set out to explore. From mountain summits in the clouds -long trailing spurs descend to the river bank. In general the slopes are -smooth-contoured and forest-clad from summit to base; only in a few -places do high cliffs diversify the scenery. The river vista everywhere -includes a rapid and small patches of _playa_ or flood plain on the -inside of the river curves. Although a true canyon hems in the river at -two celebrated passes farther down, the upper part of the river flows -in a somewhat open valley of moderate relief, with here and there a -sentinel-like peak next the river. - -A light shower fell at sunset, a typical late-afternoon downpour so -characteristic of the tropics. We landed at a small encampment of -Machigangas, built a fire against the scarred trunk of a big palm, and -made up our beds in the open, covering them with our rubber ponchos. Our -Indian neighbors gave us yuca and corn, but their neighborliness went no -further, for when our boatmen attempted to sleep under their roofs they -drove them out and fastened as securely as possible the shaky door of -their hut. - -All our efforts to obtain Indians, both here and elsewhere, proved -fruitless. One excuse after another was overcome; they plainly coveted -the trinkets, knives, machetes, muskets, and ammunition that we offered -them; and they appeared to be friendly enough. Only after repeated -assurances of our friendship could we learn the real reason for their -refusal. Some of them were escaped rubber pickers that had been captured -by white raiders several years before, and for them a return to the -rubber country meant enslavement, heavy floggings, and separation from -their numerous wives. The hardships they had endured, their final -escape, the cruelty of the rubber men, and the difficult passage of the -rapids below were a set of circumstances that nothing in our list of -gifts could overcome. My first request a week before had so sharpened -their memory that one of them related the story of his wrongs, a recital -intensely dramatic to the whole circle of his listeners, including -myself. Though I did not understand the details of his story, his tones -and gesticulations were so effective that they held me as well as his -kinsmen of the woods spellbound for over an hour. - -It is appalling to what extent this great region has been depopulated by -the slave raiders and those arch enemies of the savage, smallpox and -malaria. At Rosalina, over sixty Indians died of malaria in one year; -and only twenty years ago seventy of them, the entire population of the -Pongo, were swept away by smallpox. For a week we passed former camps -near small abandoned clearings, once the home of little groups of -Machigangas. Even the summer shelter huts on the sand-bars, where the -Indians formerly gathered from their hill homes to fish, are now almost -entirely abandoned. Though our men carefully reconnoitered each one for -fear of ambush, the precaution was needless. Below the Coribeni the -Urubamba is a great silent valley. It is fitted by Nature to support -numerous villages, but its vast solitudes are unbroken except at night, -when a few families that live in the hills slip down to the river to -gather yuca and cane. - -By noon of the second day’s journey we reached the head of the great -rapid at the mouth of the Sirialo. We had already run the long Coribeni -rapid, visited the Indian huts at the junction of the big Coribeni -tributary, exchanged our canoe for a larger and steadier one, and were -now to run one of the ugliest rapids of the upper river. The rapid is -formed by the gravel masses that the Sirialo brings down from the -distant Cordillera Vilcapampa. They trail along for at least a -half-mile, split the river into two main currents and nearly choke the -mouth of the tributary. For almost a mile above this great barrier the -main river is ponded and almost as quiet as a lake. - -We let our craft down this rapid by ropes, and in the last difficult -passage were so roughly handled by our almost unmanageable canoe as to -suffer from several bad accidents. All of the party were injured in one -way or another, while I suffered a fracture sprain of the left foot that -made painful work of the rest of the river trip. - -At two points below Rosalina the Urubamba is shut in by steep mountain -slopes and vertical cliffs. Canoe navigation below the Sirialo and -Coribeni rapids is no more hazardous than on the rapids of our northern -rivers, except at the two “pongos†or narrow passages. The first occurs -at the sharpest point of the abrupt curve shown on the map; the second -is the celebrated Pongo de Mainique. In these narrow passages in time of -high water there is no landing for long stretches. The bow paddler -stands well forward and tries for depth and current; the stern paddler -keeps the canoe steady in its course. When paddlers are in agreement -even a heavy canoe can be directed into the most favorable channels. -Our canoemen were always in disagreement, however, and as often as not -we shot down rapids at a speed of twenty miles an hour, broadside on, -with an occasional bump on projecting rocks or boulders whose warning -ordinary boatmen would not let go unheeded. - -The scenery at the great bend is unusually beautiful. The tropical -forest crowds the river bank, great cliffs rise sheer from the water’s -edge, their faces overhung with a trailing drapery of vines, and in the -longer river vistas one may sometimes see the distant heights of the -Cordillera Vilcapampa. We shot the long succession of rapids in the -first canyon without mishap, and at night pitched our tent on the edge -of the river near the mouth of the Manugali. - -From the sharp peak opposite our camp we saw for the first time the -phenomenon of cloud-banners. A light breeze was blowing from the western -mountains and its vapor was condensed into clouds that floated down the -wind and dissolved, while they were constantly forming afresh at the -summit. In the night a thunderstorm arose and swept with a roar through -the vast forest above us. The solid canopy of the tropical forest fairly -resounded with the impact of the heavy raindrops. The next morning all -the brooks from the farther side of the river were in flood and the -river discolored. When we broke camp the last mist wraiths of the storm -were still trailing through the tree-tops and wrapped about the peak -opposite our camp, only parting now and then to give us delightful -glimpses of a forest-clad summit riding high above the clouds. - -The alternation of deeps and shallows at this point in the river and the -well-developed canyon meanders are among the most celebrated of their -kind in the world. Though shut in by high cliffs and bordered by -mountains the river exhibits a succession of curves so regular that one -might almost imagine the country a plain from the pattern of the -meanders. The succession of smooth curves for a long distance across -existing mountains points to a time when a lowland plain with moderate -slopes drained by strongly meandering rivers was developed here. Uplift -afforded a chance for renewed down-cutting on the part of all the -streams, and the incision of the meanders. The present meanders are, of -course, not the identical ones that were formed on the lowland plain; -they are rather their descendants. Though they still retain their -strongly curved quality, and in places have almost cut through the -narrow spurs between meander loops, they are not smooth like the -meanders of the Mississippi. Here and there are sharp irregular turns -that mar the symmetry of the larger curves. The alternating bands of -hard and soft rock have had a large part in making the course more -irregular. The meanders have responded to the rock structure. Though -regular in their broader features they are irregular and deformed in -detail. - -Deeps and shallows are known in every vigorous river, but it is seldom -that they are so prominently developed as in these great canyons. At one -point in the upper canyon the river has been broadened into a lake two -or three times the average width of the channel and with a scarcely -perceptible current; above and below the “laguna,†as the boatmen call -it, are big rapids with beds so shallow that rocks project in many -places. In the Pongo de Mainique the river is at one place only fifty -feet wide, yet so deep that there is little current. It is on the banks -of the quiet stretches that the red forest deer grazes under leafy -arcades. Here, too, are the boa-constrictor trails several feet wide and -bare like a roadway. At night the great serpents come trailing down to -the river’s edge, where the red deer and the wildcat, or so-called -“tiger,†are their easy prey. - -It is in such quiet stretches that one also finds the vast colonies of -water skippers. They dance continuously in the sun with an incessant -motion from right to left and back again. Occasionally one dances about -in circles, then suddenly darts through the entire mass, though without -striking his equally erratic neighbors. An up-and-down motion still -further complicates the effect. It is positively bewildering to look -intently at the whirling multitude and try to follow their complicated -motions. Every slight breath of wind brings a shock to the organization -of the dance. For though they dance only in the sun, their favorite -places are the sunny spots in the shade near the bank, as beneath an -overhanging tree. When the wind shakes the foliage the mottled pattern -of shade and sunlight is confused, the dance slows down, and the dancers -become bewildered. In a storm they seek shelter in the jungle. The hot, -quiet, sunlit days bring out literally millions of these tiny creatures. - -One of the longest deeps in the whole Urubamba lies just above the Pongo -at Mulanquiato. We drifted down with a gentle current just after sunset. -Shrill whistles, like those of a steam launch, sounded from either bank, -the strange piercing notes of the lowland cicada, _cicada tibicen_. Long -decorated canoes, better than any we had yet seen, were drawn up in the -quiet coves. Soon we came upon the first settlement. The owner, Señor -Pereira, has gathered about him a group of Machigangas, and by marrying -into the tribe has attained a position of great influence among the -Indians. Upon our arrival a gun was fired to announce to his people that -strangers had come, upon which the Machigangas strolled along in twos -and threes from their huts, helped us ashore with the baggage, and -prepared the evening meal. Here we sat down with five Italians, who had -ventured into the rubber fields with golden ideas as to profits. After -having lost the larger part of their merchandise, chiefly cinchona, in -the rapids the year before, they had established themselves here with -the idea of picking rubber. Without capital, they followed the ways of -the itinerant rubber picker and had gathered “caucho,†the poorer of the -two kinds of rubber. No capital is required; the picker simply cuts down -the likeliest trees, gathers the coagulated sap, and floats it -down-stream to market. After a year of this life they had grown restless -and were venturing on other schemes for the great down-river rubber -country. - -[Illustration: FIG. 13--Composition of tropical vegetation in the rain -forest above Pongo de Mainique, elevation 2,500 feet (760 m.). Scores of -species occur within the limits of a single photograph.] - -[Illustration: FIG. 14--The mule trail in the rain forest between -Rosalina and Pongo de Mainique. Each pool is from one and a half to two -feet deep. Even in the dry season these holes are full of water, for the -sunlight penetrates the foliage at a few places only.] - -[Illustration: FIG. 15--Topography and vegetation from the Tocate pass, -7,100 feet (2,164 m.), between Rosalina and Pongo de Mainique. See Fig. -53a. This is in the zone of maximum rainfall. The cumulo-nimbus clouds -are typical and change to nimbus in the early afternoon.] - -[Illustration: FIG. 16--The Expedition’s thirty-foot canoe at the mouth -of the Timpia below Pongo de Mainique.] - -A few weeks later, on returning through the forest, we met their -carriers with a few small bundles, the only part of their cargo they had -saved from the river. Without a canoe or the means to buy one they had -built rafts, which were quickly torn to pieces in the rapids. We, too, -should have said “_pobres Italianos_†if their venture had not been -plainly foolish. The rubber territory is difficult enough for men -with capital; for men without capital it is impossible. Such men either -become affiliated with organized companies or get out of the region when -they can. A few, made desperate by risks and losses, cheat and steal -their way to rubber. Two years before our trip an Italian had murdered -two Frenchmen just below the Pongo and stolen their rubber cargo, -whereupon he was shot by Machigangas under the leadership of Domingo, -the chief who was with us on a journey from Pongo de Mainique to the -mouth of the Timpia. Afterward they brought his skull to the top of a -pass along the forest trail and set it up on a cliff at the very edge of -Machiganga-land as a warning to others of his kind. - -At Mulanquiato we secured five Machigangas and a boy interpreter, and on -August 17 made the last and most difficult portion of our journey. We -found these Indians much more skilful than our earlier boatmen. -Well-trained, alert, powerful, and with excellent team-play, they swept -the canoe into this or that thread of the current, and took one after -another of the rapids with the greatest confidence. No sooner had we -passed the Sintulini rapids, fully a mile long, than we reached the -mouth of the Pomareni. This swift tributary comes in almost at right -angles to the main river and gives rise to a confusing mass of standing -waves and conflicting currents rendered still more difficult by the -whirlpool just below the junction. So swift is the circling current of -the maëlstrom that the water is hollowed out like a great bowl, a really -formidable point and one of our most dangerous passages; a little too -far to the right and we should be thrown over against the cliff-face; a -little too far to the left and we should be caught in the whirlpool. -Once in the swift current the canoe became as helpless as a chip. It was -turned this way and that, each turn heading it apparently straight for -destruction. But the Indians had judged their position well, and though -we seemed each moment in a worse predicament, we at last skimmed the -edge of the whirlpool and brought our canoe to shore just beyond its -rim. - -A little farther on we came to the narrow gateway of the Pongo, where -the entire volume of the river flows between cliffs at one point no -more than fifty feet apart. Here are concentrated the worst rapids of -the lower Urubamba. For nearly fifteen miles the river is an unbroken -succession of rapids, and once within its walls the Pongo offers small -chance of escape. At some points we were fortunate enough to secure a -foothold along the edge of the river and to let our canoe down by ropes. -At others we were obliged to take chances with the current, though the -great depth of water in most of the Pongo rapids makes them really less -formidable in some respects than the shallow rapids up stream. The chief -danger here lies in the rotary motion of the water at the sharpest -bends. The effect at some places is extraordinary. A floating object is -carried across stream like a feather and driven at express-train speed -against a solid cliff. In trying to avoid one of these cross-currents -our canoe became turned midstream, we were thrown this way and that, and -at last shot through three standing waves that half filled the canoe. - -Below the worst rapids the Pongo exhibits a swift succession of natural -wonders. Fern-clad cliffs border it, a bush resembling the juniper -reaches its dainty finger-like stems far out over the river, and the -banks are heavily clad with mosses. The great woods, silent, -impenetrable, mantle the high slopes and stretch up to the limits of -vision. Cascades tumble from the cliff summits or go rippling down the -long inclines of the slate beds set almost on edge. Finally appear the -white pinnacles of limestone that hem in the narrow lower entrance or -outlet of the Pongo. Beyond this passage one suddenly comes out upon the -edge of a rolling forest-clad region, the rubber territory, the country -of the great woods. Here the Andean realm ends and Amazonia begins. - -From the summits of the white cliffs 4,000 feet above the river we were -in a few days to have one of the most extensive views in South America. -The break between the Andean Cordillera and the hill-dotted plains of -the lower Urubamba valley is almost as sharp as a shoreline. The rolling -plains are covered with leagues upon leagues of dense, shadowy, -fever-haunted jungle. The great river winds through in a series of -splendid meanders, and with so broad a channel as to make it visible -almost to the horizon. Down river from our lookout one can reach ocean -steamers at Iquitos with less than two weeks of travel. It is three -weeks to the Pacific _via_ Cuzco and more than a month if one takes the -route across the high bleak lava-covered country which we were soon to -cross on our way to the coast at Camaná. - - - - -CHAPTER III - -THE RUBBER FORESTS - - -The white limestone cliffs at Pongo de Mainique are a boundary between -two great geographic provinces (Fig. 17). Down valley are the vast river -plains, drained by broad meandering rivers; up valley are the rugged -spurs of the eastern Andes and their encanyoned streams (Fig. 18). There -are outliers of the Andes still farther toward the northeast where hangs -the inevitable haze of the tropical horizon, but the country beyond them -differs in no important respect from that immediately below the Pongo. - -[Illustration: FIG. 17--Regional diagram of the Eastern Andes (here the -Cordillera Vilcapampa) and the adjacent tropical plains. For an -explanation of the method of construction and the symbolism of the -diagram see p. 51.] - -The foot-path to the summit of the cliffs is too narrow and steep for -even the most agile mules. It is simply impassable for animals without -hands. In places the packs are lowered by ropes over steep ledges and -men must scramble down from one projecting root or swinging vine to -another. In the breathless jungle it is a wearing task to pack in all -supplies for the station below the Pongo and to carry out the season’s -rubber. Recently however the ancient track has been replaced by a road -that was cut with great labor, and by much blasting, across the mountain -barrier, and at last mule transport has taken the place of the Indian. - -[Illustration: FIG. 18--Index map for the nine regional diagrams in the -pages following. A represents Fig. 17; B, 42; C, 36; D, 32; E, 34; F, -25; G, 26; and H, 65.] - -In the dry season it is a fair and delightful country--that on the -border of the mountains. In the wet season the traveler is either -actually marooned or he must slosh through rivers of mud and water that -deluge the trails and break the hearts of his beasts (Fig. 14). Here and -there a large shallow-rooted tree has come crashing down across the -trail and with its four feet of circumference and ten feet of plank -buttress it is as difficult to move as a house. A new trail must be cut -around it. A little farther on, where the valley wall steepens and one -may look down a thousand feet of slope to the bed of a mountain torrent, -a patch of trail has become soaked with water and the mules pick their -way, trembling, across it. Two days from Yavero one of our mules went -over the trail, and though she was finally recovered she died of her -injuries the following night. After a month’s work in the forest a mule -must run free for two months to recover. The packers count on losing one -beast out of five for every journey into the forest. It is not solely a -matter of work, though this is terrific; it is quite largely a matter of -forage. In spite of its profusion of life (Fig. 13) and its really vast -wealth of species, the tropical forest is all but barren of grass. Sugar -cane is a fair substitute, but there are only a few cultivated spots. -The more tender leaves of the trees, the young shoots of cane in the -_carrizo_ swamps, and the grass-like foliage of the low bamboo are the -chief substitutes for pasture. But they lead to various disorders, -besides requiring considerable labor on the part of the dejected peons -who must gather them after a day’s heavy work with the packs. - -Overcoming these enormous difficulties is expensive and some one must -pay the bill. As is usual in a pioneer region, the native laborer pays a -large part of it in unrequited toil; the rest is paid by the rubber -consumer. For this is one of the cases where a direct road connects the -civilized consumer and the barbarous producer. What a story it could -tell if a ball of smoke-cured rubber on a New York dock were endowed -with speech--of the wet jungle path, of enslaved peons, of vile abuses -by immoral agents, of all the toil and sickness that make the tropical -lowland a reproach! - -[Illustration: FIG. 19--Moss-draped trees in the rain forest near Abra -Tocate between Rosalina and Pongo de Mainique.] - -[Illustration: FIG. 20--Yavero, a rubber station on the Yavero -(Paucartambo) River, a tributary of the Urubamba. Elevation 1,600 feet -(490 m.).] - -In the United States the specter of slavery haunted the national -conscience almost from the beginning of national life, and the ghost was -laid only at the cost of one of the bloodiest wars in history. In other -countries, as in sugar-producing Brazil, the freeing of the slaves meant -not a war but the verge of financial ruin besides a fundamental -change in the social order and problems as complex and wearisome as any -that war can bring. Everywhere abolition was secured at frightful cost. - -[Illustration: FIG. 21--Clearing in the tropical forest between Rosalina -and Pabellon. This represents the border region where the -forest-dwelling Machiganga Indians and the mountain Indians meet. The -clearings are occupied by Machigangas whose chief crops are yuca and -corn; in the extreme upper left-hand corner are grassy slopes occupied -by Quechua herdsmen and farmers who grow potatoes and corn.] - -The spirit that upheld the new founders of the western republics in -driving out slavery was admirable, but as much cannot be said of their -work of reconstruction. We like to pass over those dark days in our own -history. In South America there has lingered from the old slave-holding -days down to the present, a labor system more insidious than slavery, -yet no less revolting in its details, and infinitely more difficult to -stamp out. It is called peonage; it should be called slavery. In -Bolivia, Peru, and Brazil it flourishes now as it ever did in the -fruitful soil of the interior provinces where law and order are bywords -and where the scarcity of workmen will long impel men to enslave labor -when they cannot employ it. Peonage _is_ slavery, though as in all slave -systems there are many forms under which the system is worked out. We -commonly think that the typical slave is one who is made to work hard, -given but little food, and at the slightest provocation is tied to a -post and brutally whipped. This is indeed the fate of many slaves or -“peons†so-called, in the Amazon forests; but it is no more the rule -than it was in the South before the war, for a peon is a valuable piece -of property and if a slave raider travel five hundred miles through -forest and jungle-swamp to capture an Indian you may depend upon it that -he will not beat him to death merely for the fun of it. - -That unjust and frightfully cruel floggings are inflicted at times and -in some places is of course a result of the lack of official restraint -that drunken owners far from the arm of the law sometimes enjoy. When a -man obtains a rubber concession from the government he buys a kingdom. -Many of the rubber territories are so remote from the cities that -officials can with great difficulty be secured to stay at the customs -ports. High salaries must be paid, heavy taxes collected, and grafting -of the most flagrant kind winked at. Often the concessionaire himself is -chief magistrate of his kingdom by law. Under such a system, remote from -all civilizing influences, the rubber producer himself oftentimes a -lawless border character or a downright criminal, no system of -government would be adequate, least of all one like peonage that permits -or ignores flagrant wrongs because it is so expensive to enforce -justice. - -The peonage system continues by reason of that extraordinary difficulty -in the development of the tropical lowland of South America--the lack of -a labor supply. The population of Amazonia now numbers less than one -person to the square mile. The people are distributed in small groups of -a dozen to twenty each in scattered villages along the river banks or in -concealed clearings reached by trails known only to the Indians. Nearly -all of them still live in the same primitive state in which they lived -at the time of the Discovery. In the Urubamba region a single cotton -shirt is worn by the married men and women, while the girls and boys in -many cases go entirely naked except for a loincloth or a necklace of -nuts or monkeys’ teeth (Fig. 23). A cane hut with a thatch to keep out -the heavy rains is their shelter and their food is the yuca, sugar cane, -Indian corn, bananas of many kinds, and fish. A patch of yuca once -planted will need but the most trifling attention for years. The small -spider monkey is their greatest delicacy and to procure it they will -often abandon every other project and return at their own sweet and -belated will. - -[Illustration: FIG. 22--Trading with Machiganga Indians in a reed swamp -at Santao Anato, Urubamba Valley, before Rosalina. Just outside the -picture on the right is a platform on which corn is stored for -protection against rodents and mildew. On the left is the corner of a -grass-thatched cane hut.] - -In the midst of this natural life of the forest-dwelling Indian appears -the rubber man, who, to gather rubber, must have rubber “pickers.†If he -lives on the edge of the great Andean Cordillera, laborers may be -secured from some of the lower valleys, but they must be paid well for -even a temporary stay in the hot and unhealthful lowlands. Farther out -in the great forest country the plateau Indians will not go and only the -scattered tribes remain from which to recruit laborers. For the -nature-life of the Indian what has the rubber gatherer to offer? Money? -The Indian uses it for ornament only. When I once tried with money to -pay an Indian for a week’s services he refused it. In exchange for his -severe labor he wanted nothing more than a fish-hook and a ring, the two -costing not more than a penny apiece! When his love for ornament has -once been gratified the Indian ceases to work. His food and shelter -and clothing are of the most primitive kind, but they are the best in -the world for him because they are the only kind he has known. So where -money and finery fail the lash comes in. The rubber man says that the -Indian is lazy and must be made to work; that there is a great deal of -work to be done and the Indian is the only laborer who can be found; -that if rubber and chocolate are produced the Indian must be made to -produce them; and that if he will not produce them for pay he must be -enslaved. - -[Illustration: FIG. 23--Ornaments and fabrics of the Machiganga Indians -at Yavero. The nuts are made up into strings, pendants, and heavy -necklaces. To the left of the center is one that contains feathers and -four drumsticks of a bird about the size of a small wild -turkey--probably the so-called turkey inhabiting the eastern mountain -valleys and the adjacent border of the plains, and hunted as an -important source of food. The cord in the upper right-hand corner is -used most commonly for heel supports in climbing trees. The openwork -sack is convenient for carrying game, fish, and fruit; the finely woven -sacks are used for carrying red ochre for ornamenting or daubing faces -and arms. They are also used for carrying corn, trinkets, and game.] - -It is a law of the rubber country that when an Indian falls into debt to -a white man he must work for the latter until the debt is discharged. If -he runs away before the debt is canceled or if he refuses to work or -does too little work he may be flogged. Under special conditions such -laws are wise. In the hands of the rubber men they are the basis of -slavery. For, once the rubber interests begin to suffer, the promoters -look around for a chance to capture free Indians. An expedition is -fitted out that spends weeks exploring this river or that in getting on -the track of unattached Indians. When a settlement is found the men are -enslaved and taken long distances from home finally to reach a rubber -property. There they are given a corner of a hut to sleep in, a few -cheap clothes, a rubber-picking outfit, and a name. In return for these -articles the unwilling Indian is charged any fanciful price that comes -into the mind of his “owner,†and he must thereupon work at a per diem -wage also fixed by the owner. Since his obligations increase with time, -the Indian may die over two thousand dollars in debt! - -Peonage has left frightful scars upon the country. In some places the -Indians are fugitives, cultivating little farms in secreted places but -visiting them only at night or after carefully reconnoitering the spot. -They change their camps frequently and make their way from place to -place by secret trails, now spending a night or two under the shelter of -a few palm leaves on a sandbar, again concealing themselves in almost -impenetrable jungle. If the hunter sometimes discovers a beaten track he -follows it only to find it ending on a cliff face or on the edge of a -lagoon where concealment is perfect. There are tribes that shoot the -white man at sight and regard him as their bitterest enemy. Experience -has led them to believe that only a dead white is a good white, -reversing our saying about the North American Indian; and that even when -he comes among them on peaceful errands he is likely to leave behind him -a trail of syphilis and other venereal diseases scarcely less deadly -than his bullets. - -However, the peonage system is not hideous everywhere and in all its -aspects. There are white owners who realize that in the long run the -friendship of the Indians is an asset far greater than unwilling service -and deadly hatred. Some of them have indeed intermarried with the -Indians and live among them in a state but little above savagery. In the -Mamoré country are a few owners of original princely concessions who -have grown enormously wealthy and yet who continue to live a primitive -life among their scores of illegitimate descendants. The Indians look -upon them as benefactors, as indeed many of them are, defending the -Indians from ill treatment by other whites, giving them clothing and -ornaments, and exacting from them only a moderate amount of labor. In -some cases indeed the whites have gained more than simple gratitude for -their humane treatment of the Indians, some of whom serve their masters -with real devotion. - -When the “rubber barons†wish to discourage investigation of their -system they invite the traveler to leave and he is given a canoe and -oarsmen with which to make his way out of the district. Refusal to -accept an offer of canoes and men is a declaration of war. An agent of -one of the London companies accepted such a challenge and was promptly -told that he would not leave the territory alive. The threat would have -held true in the case of a less skilful man. Though Indians slept in the -canoes to prevent their seizure, he slipped past the guards in the -night, swam to the opposite shore, and there secured a canoe within -which he made a difficult journey down river to the nearest post where -food and an outfit could be secured. - -A few companies operating on or near the border of the Cordillera have -adopted a normal labor system, dependent chiefly upon people from the -plateau and upon the thoroughly willing assistance of well-paid forest -Indians. The Compañia Gomera de Mainique at Puerto Mainique just below -the Pongo is one of these and its development of the region without -violation of native rights is in the highest degree praiseworthy. In -fact the whole conduct of this company is interesting to a geographer, -as it reflects at every point the physical nature of the country. - -The government is eager to secure foreign capital, but in eastern Peru -can offer practically nothing more than virgin wealth, that is, land and -the natural resources of the land. There are no roads, virtually no -trails, no telegraph lines, and in most cases no labor. Since the old -Spanish grants ran at right angles to the river so as to give the owners -a cross-section of varied resources, the up-river plantations do not -extend down into the rubber country. Hence the more heavily forested -lower valleys and plains are the property of the state. A man can buy a -piece of land down there, but from any tract within ordinary means only -a primitive living can be obtained. The pioneers therefore are the -rubber men who produce a precious substance that can stand the enormous -tax on production and transportation. They do not want the land--only -the exclusive right to tap the rubber trees upon it. Thus there has -arisen the concession plan whereby a large tract is obtained under -conditions of money payment or of improvements that will attract -settlers or of a tax on the export. - -The “caucho†or poorer rubber of the Urubamba Valley begins at 3,000 -feet (915 m.) and the “hevea†or better class is a lower-valley and -plains product. The rubber trees thereabouts produce 60 grams (2 ozs.) -of dry rubber each week for eight months. After yielding rubber for this -length of time a tree is allowed to rest four or five years. “Caucho†is -produced from trees that are cut down and ringed with machetes, but it -is from fifty to sixty cents cheaper owing to the impurities that get -into it. The wood, not the nut, of the _Palma carmona_ is used for -smoking or “curing†the rubber. The government had long been urged to -build a road into the region in place of the miserable track--absolutely -impassable in the wet season--that heretofore constituted the sole -means of exit. About ten years ago Señor Robledo at last built a -government trail from Rosalina to Yavero about 100 miles long. While it -is a wretched trail it is better than the old one, for it is more direct -and it is better drained. In the wet season parts of it are turned into -rivers and lakes, but it is probably the best that could be done with -the small grant of twenty thousand dollars. - -With at least an improvement in the trail it became possible for a -rubber company to induce _cargadores_ or packers to transport -merchandise and rubber and to have a fair chance of success. Whereupon a -rubber company was organized which obtained a concession of 28,000 -hectares (69,188 acres) of land on condition that the company finish a -road one and one-half meters wide to the Pongo, connecting with the road -which the government had extended to Yavero. The land given in payment -was not continuous but was selected in lots by the company in such a way -as to secure the best rubber trees over an area several times the size -of the concession. The road was finished by William Tell after four -years’ work at a cost of about seventy-five thousand dollars. The last -part of it was blasted out of slate and limestone and in 1912 the first -pack train entered Puerto Mainique. - -The first rubber was taken out in November, 1910, and productive -possibilities proved by the collection of 9,000 kilos (19,841 pounds) in -eight months. - -If a main road were the chief problem of the rubber company the business -would soon be on a paying basis, but for every mile of road there must -be cut several miles of narrow trail (Fig. 14), as the rubber trees grow -scattered about--a clump of a half dozen here and five hundred feet -farther on another clump and only scattered individuals between. -Furthermore, about twenty-five years ago rubber men from the Ucayali -came up here in launches and canoes and cut down large numbers of trees -within reach of the water courses and by ringing the trunks every few -feet with machetes “bled†them rapidly and thus covered a large -territory in a short time, and made huge sums of money when the price of -rubber was high. Only a few of the small trees that were left are now -mature. These, the mature trees that were overlooked, and the virgin -stands farther from the rivers are the present sources of rubber. - -In addition to the trails small cabins must be built to shelter the -hired laborers from the plateau, many of whom bring along their women -folk to cook for them. The combined expense to a company of these -necessary improvements before production can begin is exceedingly heavy. -There is only one alternative for the prospective exploiter: to become a -vagrant rubber gatherer. With tents, guns, machetes, cloth, baubles for -trading, tinned food for emergencies, and with pockets full of English -gold parties have started out to seek fortunes in the rubber forests. If -the friendship of a party of Indians can be secured by adequate gifts -large amounts of rubber can be gathered in a short time, for the Indians -know where the rubber trees grow. On the other hand, many fortunes have -been lost in the rubber country. Some of the tribes have been badly -treated by other adventurers and attack the newcomers from ambush or -gather rubber for a while only to overturn the canoe in a rapid and let -the river relieve them of selfish friends. - -The Compañia Gomera de Mainique started out by securing the good-will of -the forest Indians, the Machigangas. They come and go in friendly visits -to the port at Yavero. If one of them is sick he can secure free -medicine from the agent. If he wishes goods on credit he has only to ask -for them, for the agent knows that the Indian’s sense of fairness will -bring him back to work for the company. Without previous notice a group -of Indians appears: - -“We owe,†they announce. - -“Good,†says the agent, “build me a house.†- -They select the trees. Before they cut them down they address them -solemnly. The trees must not hold their destruction against the Indians -and they must not try to resist the sharp machetes. Then the Indians set -to work. They fell a tree, bind it with light ropes woven from the wild -cotton, and haul it to its place. That is all for the day. They play in -the sun, do a little hunting, or look over the agent’s house, touching -everything, talking little, exclaiming much. They dip their wet fingers -in the sugar bowl and taste, turn salt out upon their hands, hold -colored solutions from the medicine chest up to the light, and pull out -and push in the corks of the bottles. At the end of a month or two the -house is done. Then they gather their women and babies together and say: - -“Now we go,†without asking if the work corresponds with the cost of the -articles they had bought. Their judgment is good however. Their work is -almost always more valuable than the articles. Then they shake hands all -around. - -“We will come again,†they say, and in a moment have disappeared in the -jungle that overhangs the trail. - -With such labor the Compañia Gomera de Mainique can do something, but it -is not much. The regular seasonal tasks of road-building and -rubber-picking must be done by imported labor. This is secured chiefly -at Abancay, where live groups of plateau Indians that have become -accustomed to the warm climate of the Abancay basin. They are employed -for eight or ten months at an average rate of fifty cents gold per day, -and receive in addition only the simplest articles of food. - -At the end of the season the gang leaders are paid a _gratificación_, or -bonus, the size of which depends upon the amount of rubber collected, -and this in turn depends upon the size of the gang and the degree of -willingness to work. In the books of the company I saw a record of -_gratificaciónes_ running as high as $600 in gold for a season’s work. - -Some of the laborers become sick and are cared for by the agent until -they recover or can be sent back to their homes. Most of them have fever -before they return. - -The rubber costs the company two _soles_ ($1.00) produced at Yavero. The -two weeks’ transportation to Cuzco costs three and a half soles ($1.75) -per twenty-five pounds. The exported rubber, known to the trade as -Mollendo rubber, in contrast to the finer “Pará†rubber from the lower -Amazon, is shipped to Hamburg. The cost for transportation from port to -port is $24.00 per English ton (1,016 kilos). There is a Peruvian tax of -8 per cent of the net value in Europe, and a territorial tax of two -soles ($1.00) per hundred pounds. All supplies except the few vegetables -grown on the spot cost tremendously. Even dynamite, hoes, clothing, -rice--to mention only a few necessities--must pay the heavy cost of -transportation after imposts, railroad and ocean freight, storage and -agents’ percentages are added. The effect of a disturbed market is -extreme. When, in 1911, the price of rubber fell to $1.50 a kilo at -Hamburg the company ceased exporting. When it dropped still lower in -1912 production also stopped, and it is still doubtful, in view of the -growing competition of the East-Indian plantations with their cheap -labor, whether operations will ever be resumed. Within three years no -less than a dozen large companies in eastern Peru and Bolivia have -ceased operations. In one concession on the Madre de Dios the withdrawal -of the agents and laborers from the posts turned at last into flight, as -the forest Indians, on learning the company’s policy, rapidly ascended -the river in force, committing numerous depredations. The great war has -also added to the difficulties of production. - -Facts like these are vital in the consideration of the future of the -Amazon basin and especially its habitability. It was the dream of -Humboldt that great cities should arise in the midst of the tropical -forests of the Amazon and that the whole lowland plain of that river -basin should become the home of happy millions. Humboldt’s vision may -have been correct, though a hundred years have brought us but little -nearer its realization. Now, as in the past four centuries, man finds -his hands too feeble to control the great elemental forces which have -shaped history. The most he can hope for in the next hundred years at -least is the ability to dodge Nature a little more successfully, and -here and there by studies in tropical hygiene and medicine, by the -substitution of water-power for human energy, to carry a few of the -outposts and prepare the way for a final assault in the war against the -hard conditions of climate and relief. We hear of the Madeira-Mamoré -railroad, 200 miles long, in the heart of a tropical forest and of the -commercial revolution it will bring. Do we realize that the forest which -overhangs the rails is as big as the whole plain between the Rockies -and the Appalachians, and that the proposed line would extend only as -far as from St. Louis to Kansas City, or from Galveston to New Orleans? - -Even if twenty whites were eager to go where now there is but one -reluctant pioneer, we should still have but a halting development on -account of the scarcity of labor. When, three hundred years ago, the -Isthmus of Panama stood in his way, Gomara wrote to his king: “There are -mountains, but there are also hands,†as if men could be conjured up -from the tropical jungle. From that day to this the scarcity of labor -has been the chief difficulty in the lowland regions of tropical South -America. Even when medicine shall have been advanced to the point where -residence in the tropics can be made safe, the Amazon basin will lack an -adequate supply of workmen. Where Humboldt saw thriving cities, the -population is still less than one to the square mile in an area as large -as fifteen of our Mississippi Valley states. We hear much about a rich -soil and little about intolerable insects; the climate favors a good -growth of vegetation, but a man can starve in a tropical forest as -easily as in a desert; certain tributaries of the Negro are bordered by -rich rubber forests, yet not a single Indian hut may be found along -their banks. Will men of the white race dig up the rank vegetation, -sleep in grass hammocks, live in the hot and humid air, or will they -stay in the cooler regions of the north and south? Will they rear -children in the temperate zones, or bury them in the tropics? - -What Gorgas did for Panama was done for intelligent people. Can it be -duplicated in the case of ignorant and stupid laborers? Shall the white -man with wits fight it out with Nature in a tropical forest, or fight it -out with his equals under better skies? - -The tropics must be won by strong hands of the lowlier classes who are -ignorant or careless of hygiene, and not by the khaki-clad robust young -men like those who work at Panama. Tropical medicine can do something -for these folk, but it cannot do much. And we cannot surround every -laborer’s cottage with expensive screens, oiled ditches, and well-kept -lawns. There is a practical optimism and a sentimental optimism. The one -is based on facts; the other on assumptions. It is pleasant to think -that the tropical forest may be conquered. It is nonsense to say that we -are now conquering it in any comprehensive and permanent way. That sort -of conquest is still a dream, as when Humboldt wrote over a hundred -years ago. - - - - -CHAPTER IV - -THE FOREST INDIANS - - -The people of a tropical forest live under conditions not unlike those -of the desert. The Sahara contains 2,000,000 persons within its borders, -a density of one-half to the square mile. This is almost precisely the -density of population of a tract of equivalent size in the lowland -forests of South America. Like the oases groups in the desert of aridity -are the scattered groups along the river margins of the forest. The -desert trails run from spring to spring or along a valley floor where -there is seepage or an intermittent stream; the rivers are the highways -of the forest, the flowing roads, and away from them one is lost in as -true a sense as one may be lost in the desert. - -A man may easily starve in the tropical forest. Before starting on even -a short journey of two or three days a forest Indian stocks his canoe -with sugar cane and yuca and a little parched corn. He knows the -settlements as well as his desert brother knows the springs. The Pahute -Indian of Utah lives in the irrigated valleys and makes annual -excursions across the desert to the distant mountains to gather the -seeds of the nut pine. The Machiganga lives in the hills above the -Urubamba and annually comes down through the forest to the river to fish -during the dry season. - -The Machigangas are one of the important tribes of the Amazon basin. -Though they are dispersed to some extent upon the plains their chief -groups are scattered through the heads of a large number of valleys near -the eastern border of the Andes. Chief among the valleys they occupy are -the Pilcopata, Tono, Piñi-piñi, Yavero, Yuyato, Shirineiri, Ticumpinea, -Timpia, and Camisea (Fig. 203). In their distribution, in their -relations with each other, in their manner of life, and to some extent -in their personal traits, they display characteristics strikingly like -those seen in desert peoples. Though the forest that surrounds them -suggests plenty and the rivers the possibility of free movement with -easy intercourse, the struggle of life, as in the desert, is against -useless things. Travel in the desert is a conflict with heat and -aridity; but travel in the tropic forest is a struggle against space, -heat, and a superabundant and all but useless vegetation. - -The Machigangas are one of the subtribes of the Campas Indians, one of -the most numerous groups in the Amazon Valley. It is estimated that -there are in all about 14,000 to 16,000 of them. Each subtribe numbers -from one to four thousand, and the territory they occupy extends from -the limits of the last plantations--for example, Rosalina in the -Urubamba Valley--downstream beyond the edge of the plains. Among them -three subtribes are still hostile to the whites: the Cashibos, the -Chonta Campas, and the Campas Bravos. - -In certain cases the Cashibos are said to be anthropophagous, in the -belief that they will assume the strength and intellect of those they -eat. This group is also continuously at war with its neighbors, goes -naked, uses stone hatchets, as in ages past, because of its isolation -and unfriendliness, and defends the entrances to the tribal huts with -dart and traps. The Cashibos are diminishing in numbers and are now -scattered through the valley of the Gran Pajonal, the left bank of the -Pachitea, and the Pampa del Sacramento.[2] - -The friendliest tribes live in the higher valley heads, where they have -constant communication with the whites. The use of the bow and arrow has -not, however, been discontinued among them, in spite of the wide -introduction of the old-fashioned muzzle-loading shotgun, which they -prize much more highly than the latest rifle or breech-loading shotgun -because of its simplicity and cheapness. Accidents are frequent among -them owing to the careless use of fire-arms. On our last day’s journey -on the Urubamba above the mouth of the Timpia one of our Indian boys -dropped his canoe pole on the hammer of a loaded shotgun, and not only -shot his own fingers to pieces, but gravely wounded his father (Fig. 2). -In spite of his suffering the old chief directed our work at the canoe -and even was able to tell us the location of the most favorable channel. -Though the night that followed was as black as ink, with even the stars -obscured by a rising storm, his directions never failed. We poled our -way up five long rapids without special difficulties, now working into -the lee of a rock whose location he knew within a few yards, now -paddling furiously across the channel to catch the upstream current of -an eddy. - -The principal groups of Machigangas live in the middle Urubamba and its -tributaries, the Yavero, Yuyato, Shirineiri, Ticumpinea, Timpia, -Pachitea, and others. There is a marked difference in the use of the -land and the mode of life among the different groups of this subtribe. -Those who live in the lower plains and river “playas,†as the patches of -flood plain are called, have a single permanent dwelling and alternately -fish and hunt. Those that live on hill farms have temporary reed huts on -the nearest sandbars and spend the best months of the dry season--April -to October--in fishing and drying fish to be carried to their mountain -homes (Fig. 21). Some families even duplicate _chacras_ or farms at the -river bank and grow yuca and sugar cane. In latter years smallpox, -malaria, and the rubber hunters have destroyed many of the river -villages and driven the Indians to permanent residence in the hills or, -where raids occur, along secret trails to hidden camps. - -Their system of agriculture is strikingly adapted to some important -features of tropical soil. The thin hillside soils of the region are but -poorly stocked with humus, even in their virgin condition. Fallen trees -and foliage decay so quickly that the layer of forest mold is -exceedingly thin and the little that is incorporated in the soil is -confined to a shallow surface layer. To meet these special conditions -the Indian makes new clearings by girdling and burning the trees. When -the soil becomes worn out and the crops diminish, the old clearing is -abandoned and allowed to revert to natural growth and a new farm is -planted to corn and yuca. The population is so scattered and thin that -the land assignment system current among the plateau Indians is not -practised among the Machigangas. Several families commonly live together -and may be separated from their nearest neighbors by many miles of -forested mountains. The land is free for all, and, though some heavy -labor is necessary to clear it, once a small patch is cleared it is easy -to extend the tract by limited annual cuttings. Local tracts of -naturally unforested land are rarely planted, chiefly because the -absence of shade has allowed the sun to burn out the limited humus -supply and to prevent more from accumulating. The best soil of the -mountain slopes is found where there is the heaviest growth of timber, -the deepest shade, the most humus, and good natural drainage. It is the -same on the playas along the river; the recent additions to the flood -plain are easy to cultivate, but they lack humus and a fine matrix which -retains moisture and prevents drought or at least physiologic dryness. -Here, too, the timbered areas or the cane swamps are always selected for -planting. - -The traditions of the Machigangas go back to the time of the Inca -conquest, when the forest Indians, the “Antis,†were subjugated and -compelled to pay tribute.[3] When the Inca family itself fled from Cuzco -after the Spanish Conquest and sought refuge in the wilderness it was to -the Machiganga country that they came by way of the Vilcabamba and -Pampaconas Valleys. Afterward came the Spaniards and though they did not -exercise governmental authority over the forest Indians they had close -relations with them. Land grants were made to white pioneers for special -services or through sale and with the land often went the right to -exploit the people on it. Some of the concessions were owned by people -who for generations knew nothing save by hearsay of the Indians who -dwelt in the great forests of the valleys. In later years they have been -exploring their lands and establishing so-called relations whereby the -savage “buys†a dollar’s worth of powder or knives for whatever number -of dollars’ worth of rubber the owner may care to extract from him. - -The forest Indian is still master of his lands throughout most of the -Machiganga country. He is cruelly enslaved at the rubber posts, held by -the loose bonds of a desultory trade at others, and in a few places, as -at Pongo do Mainique, gives service for both love and profit, but in -many places it is impossible to establish control or influence. The -lowland Indian never falls into the abject condition of his Quechua -brother on the plateau. He is self-reliant, proud, and independent. He -neither cringes before a white nor looks up to him as a superior being. -I was greatly impressed by the bearing of the first of the forest tribes -I met in August, 1911, at Santo Anato. I had built a brisk fire and was -enjoying its comfort when La Sama returned with some Indians whom he had -secured to clear his playa. The tallest of the lot, wearing a colored -band of deer skin around his thick hair and a gaudy bunch of yellow -feathers down his back, came up, looked me squarely in the eye, and -asked - -“Tatiry payta?†(What is your name?) - -When I replied he quietly sat down by the fire, helping himself to the -roasted corn I had prepared in the hot ashes. A few days later when we -came to the head of a rapid I was busy sketching-in my topographic map -and did not hear his twice repeated request to leave the boat while the -party reconnoitered the rapid. Watching his opportunity he came -alongside from the rear--he was steersman--and, turning just as he was -leaving the boat, gave me a whack in the forehead with his open palm. La -Sama saw the motion and protested. The surly answer was: - -“I twice asked him to get out and he didn’t move. What does he think we -run the canoe to the bank for?†- -To him the making of a map was inexplicable; I was merely a stupid white -person who didn’t know enough to get out of a canoe when told! - -The plateau Indian has been kicked about so long that all his -independence has been destroyed. His goods have been stolen, his -services demanded without recompense, in many places he has no right to -land, and his few real rights are abused beyond belief. The difference -between him and the forest Indian is due quite largely to differences of -environment. The plateau Indian is agricultural, the forest Indian -nomadic and in a hunting stage of development; the unforested plateau -offers no means for concealment of person or property, the forest offers -hidden and difficult paths, easy means for concealment, for ambush, and -for wide dispersal of an afflicted tribe. The brutal white of the -plateau follows altogether different methods when he finds himself in -the Indian country, far from military assistance, surrounded by fearless -savages. He may cheat but he does not steal, and his brutality is always -carefully suited to both time and place. - -The Machigangas are now confined to the forest, but the limits of their -territory were once farther upstream, where they were in frequent -conflict with the plateau Indians. As late as 1835, according to General -Miller,[4] they occupied the land as far upstream as the “Encuentro†-(junction) of the Urubamba and the Yanatili (Fig. 53). Miller likewise -notes that the Chuntaguirus, “a superior race of Indians†who lived -“toward the Marañon,†came up the river “200 leagues†to barter with the -people thereabouts. - -“They bring parrots and other birds, monkeys, cotton robes white and -painted, wax balsams, feet of the gran bestia, feather ornaments for the -head, and tiger and other skins, which they exchange for hatchets, -knives, scissors, needles, buttons, and any sort of glittering bauble.†- -On their yearly excursions they traveled in a band numbering from 200 to -300, since at the mouth of the Paucartambo (Yavero) they were generally -set upon by the Pucapacures. The journey upstream required three months; -with the current they returned home in fifteen days. - -Their place of meeting at the mouth of the Yanatili was a response to a -long strip of grassland that extends down the deep and dry Urubamba -Valley, as shown in Figs. 53-B and 55. The wet forests, in which the -Machigangas live, cover the hills back of the valley plantations; the -belt of dry grassland terminates far within the general limits of the -red man’s domain and only 2,000 feet above the sea. It is in this strip -of low grassland that on the one hand the highland and valley dwellers, -and on the other the Indians of the hot forested valleys and the -adjacent lowland found a convenient place for barter. The same -physiographic features are repeated in adjacent valleys of large size -that drain the eastern aspect of the Peruvian Andes, and in each case -they have given rise to the periodic excursions of the trader. - -These annual journeys are no longer made. The planters have crept down -valley. The two best playas below Rosalina are now being cleared. Only a -little space remains between the lowest valley plantations and the -highest rubber stations. Furthermore, the Indians have been enslaved by -the rubber men from the Ucayali. The Machigangas, many of whom are -runaway peons, will no longer take cargoes down valley for fear of -recapture. They have the cautious spirit of fugitives except in their -remote valleys. There they are secure and now and then reassert their -old spirit when a lawless trader tries to browbeat them into an -unprofitable trade. Also, they are yielding to the alluring call of the -planter. At Santo Anato they are clearing a playa in exchange for -ammunition, machetes, brandy, and baubles. They no longer make annual -excursions to get these things. They have only to call at the nearest -plantation. There is always a wolf before the door of the planter--the -lack of labor. Yet, as on every frontier, he turns wolf himself when the -lambs come, and without shame takes a week’s work for a penny mirror, -or, worse still, supplies them with firewater, for that will surely -bring them back to him. Since this is expensive they return to their -tribal haunts with nothing except a debauched spirit and an appetite -from which they cannot run away as they did from their task masters in -the rubber forest. Hence the vicious circle: more brandy, more labor; -more labor, more cleared land; more cleared land, more brandy; more -brandy, less Indian. But by that time the planter has a large sugar -estate. Then he can begin to buy the more expensive plateau labor, and -in turn debauch it. - -Nature as well as man works against the scattered tribes of Machigangas -and their forest kinsmen. Their country is exceedingly broken by -ramifying mountain spurs and valleys overhung with cliffs or bordered by -bold, wet, fern-clad slopes. It is useless to try to cut your way by a -direct route from one point to another. The country is mantled with -heavy forest. You must follow the valleys, the ancient trails of the -people. The larger valleys offer smooth sand-bars along the border of -which canoes may be towed upstream, and there are little cultivated -places for camps. But only a few of the tribes live along them, for they -are also more accessible to the rubbermen. The smaller valleys, -difficult of access, are more secure and there the tribal remnants live -today. While the broken country thus offers a refuge to fugitive bands -it is the broken country and its forest cover that combine to break up -the population into small groups and keep them in an isolated and -quarrelsome state. Chronic quarreling is not only the product of mere -lack of contact. It is due to many causes, among which is a union of the -habit of migration and divergent tribal speech. Every tribe has its own -peculiar words in addition to those common to the group of tribes to -which it belongs. Moreover each group of a tribe has its distinctive -words. I have seen and used carefully prepared vocabularies--no two of -which are alike throughout. They serve for communication with only a -limited number of families. These peculiarities increase as experiences -vary and new situations call for additions to or changes in their -vocabularies, and when migrating tribes meet their speech may be so -unlike as to make communication difficult. Thus arise suspicion, -misunderstanding, plunder, and chronic war. Had they been a united -people their defense of their rough country might have been successful. -The tribes have been divided and now and again, to get firearms and -ammunition with which to raid a neighbor, a tribe has joined its -fortunes to those of vagrant rubber pickers only to find in time that -its women were debased, its members decimated by strange and deadly -diseases, and its old morality undermined by an insatiable desire for -strong drink.[5] The Indian loses whether with the white or against him. - -The forest Indian is held by his environment no less strongly than the -plateau Indian. We hear much about the restriction of the plateau -dweller to the cool zone in which the llama may live. As a matter of -fact he lives far below the cool zone, where he no longer depends upon -the llama but rather upon the mule for transport. The limits of his -range correspond to the limits of the grasslands in the dry valley -pockets already described (p. 42), or on the drier mountain slopes below -the zone of heaviest rainfall (Fig. 54). It is this distribution that -brought him into such intimate contact with the forest Indian. The old -and dilapidated coca terraces of the Quechuas above the Yanatili almost -overlook the forest patches where the Machigangas for centuries built -their rude huts. A good deal has been written about the attempts of the -Incas to extend their rule into this forest zone and about the failure -of these attempts on account of the tropical climate. But the forest -Indian was held by bonds equally secure. The cold climate of the plateau -repelled him as it does today. His haunts are the hot valleys where he -need wear only a wild-cotton shirt or where he may go naked altogether. -That he raided the lands of the plateau Indian is certain, but he could -never displace him. Only along the common borders of their domains, -where the climates of two zones merged into each other, could the forest -Indian and the plateau Indian seriously dispute each other’s claims to -the land. Here was endless conflict but only feeble trade and only the -most minute exchanges of cultural elements. - -Even had they been as brothers they would have had little incentive to -borrow cultural elements from each other. The forest dweller requires -bow and arrow; the plateau dweller requires a hoe. There are fish in the -warm river shallows of the forested zone; llamas, vicuña, vizcachas, -etc., are a partial source of food supply on the plateau. Coca and -potatoes are the chief products of the grassy mountain slopes; yuca, -corn, bananas, are the chief vegetable foods grown on the tiny -cultivated patches in the forest. The plateau dweller builds a -thick-walled hut; the valley dweller a cane shack. So unlike are the two -environments that it would be strange if there had been a mixture of -racial types and cultures. The slight exchanges that were made seem -little more than accidental. Even today the Machigangas who live on the -highest slopes own a few pigs obtained from Quechuas, but they never eat -their flesh; they keep them for pets merely. I saw not a single woolen -article among the Indians along the Urubamba whereas Quechuas with -woolen clothing were going back and forth regularly. Their baubles were -of foreign make; likewise their few hoes, likewise their guns. - -They clear the forest about a mid-cotton tree and spin and weave the -cotton fiber into sacks, cords for climbing trees when they wish to -chase a monkey, ropes for hauling their canoes, shirts for the married -men and women, colored head-bands, and fish nets. The slender strong -bamboo is gathered for arrows. The chunta palm, like bone for hardness, -supplies them with bows and arrow heads. The brilliant red and yellow -feathers of forest birds, also monkey bones and teeth, are their natural -ornaments. Their life is absolutely distinct from that of their Quechua -neighbors. Little wonder that for centuries forest and plateau Indians -have been enemies and that their cultures are so distinct, for their -environment everywhere calls for unlike modes of existence and distinct -cultural development. - - - - -CHAPTER V - -THE COUNTRY OF THE SHEPHERDS - - -The lofty mountain zones of Peru, the high bordering valleys, and the -belts of rolling plateau between are occupied by tribes of shepherds. In -that cold, inhospitable region at the top of the country are the highest -permanent habitations in the world--17,100 feet (5,210 m.)--the loftiest -pastures, the greatest degree of adaptation to combined altitude and -frost. It is here only a step from Greenland to Arcady. Nevertheless it -is Greenland that has the people. Why do they shun Arcady? To the -traveler from the highlands the fertile valleys between 5,000 and 8,000 -feet (1,500 to 2,500 m.) seem like the abode of friendly spirits to -whose charm the highland dweller must yield. Every pack-train from -valley to highland carries luxury in the form of fruit, coca, cacao, and -sugar. One would think that every importation of valley products would -be followed by a wave of migration from highland to valley. On the -contrary the highland people have clung to their lofty pastures for -unnumbered centuries. Until the Conquest the last outposts of the Incas -toward the east were the grassy ridges that terminate a few thousand -feet below the timber line. - -In this natural grouping of the people where does choice or blind -prejudice or instinct leave off? Where does necessity begin? There are -answers to most of these questions to be found in the broad field of -geographic comparison. But before we begin comparisons we must study the -individual facts upon which they rest. These facts are of almost every -conceivable variety. They range in importance from a humble shepherd’s -stone corral on a mountain slope to a thickly settled mountain basin. -Their interpretation is to be sought now in the soil of rich playa -lands, now in the fixed climatic zones and rugged relief of deeply -dissected, lofty highlands in the tropics. Some of the controlling -factors are historical, others economic; still other factors have -exerted their influence through obscure psychologic channels almost -impossible to trace. The _why_ of man’s distribution over the earth is -one of the most complicated problems in natural science, and the -solution of it is the chief problem of the modern geographer. - -At first sight the mountain people of the Peruvian Andes seem to be -uniform in character and in mode of life. The traveler’s first -impression is that the same stone-walled, straw-thatched type of hut is -to be found everywhere, the same semi-nomadic life, the same degrees of -poverty and filth. Yet after a little study the diversity of their lives -is seen to be, if not a dominating fact, at least one of surprising -importance. Side by side with this diversity there runs a corresponding -diversity of relations to their physical environment. Nowhere else on -the earth are greater physical contrasts compressed within such small -spaces. If, therefore, we accept the fundamental theory of geography -that there is a general, necessary, varied, and complex relation between -man and the earth, that theory ought here to find a really vast number -of illustrations. A glance at the accompanying figures discloses the -wide range of relief in the Peruvian Andes. The corresponding range in -climate and in life therefore furnishes an ample field for the -application of the laws of human distribution. - -In analyzing the facts of distribution we shall do well to begin with -the causes and effects of migration. Primitive man is in no small degree -a wanderer. His small resources often require him to explore large -tracts. As population increases the food quest becomes more intense, and -thus there come about repeated emigrations which increase the food -supply, extend its variety, and draw the pioneers at last into contact -with neighboring groups. The farther back we go in the history of the -race the clearer it becomes that migrations lie at the root of much of -human development. The raid for plunder, women, food, beasts, is a -persistent feature of the life of those primitive men who live on the -border of unlike regions. - -The shepherd of the highland and the forest hunter of the plains -perforce range over vast tracts, and each brings back to the home group -news that confirms the tribal choice of habitation or sets it in motion -toward a more desirable place. Superstitions may lead to flight akin to -migration. Epidemics may be interpreted as the work of a malignant -spirit from which men must flee. War may drive a defeated group into the -fastnesses of a mountain forest where pursuit by stream or trail weakens -the pursuer and confines his action, thereby limiting his power. Floods -may come and destroy the cultivated spots. Want or mere desire in a -hundred forms may lead to movement. - -Even among forest tribes long stationary the facile canoe and the light -household necessities may easily enable trivial causes to develop the -spirit of restlessness. Pressure of population is a powerful but not a -general cause of movement. It may affect the settled groups of the -desert oases, or the dense population of fertile plains that is rooted -in the soil. On the other hand mere whims may start a nomadic group -toward a new goal. Often the goal is elusive and the tribe turns back to -the old haunts or perishes in the shock of unexpected conflict. - -In the case of both primitive societies and those of a higher order the -causes and the results of migration are often contradictory. These will -depend on the state of civilization and the extremes of circumstance. -When the desert blooms the farmer of the Piura Valley in northwestern -Peru turns shepherd and drives his flocks of sheep and goats out into -the short-lived pastures of the great pampa on the west. In dry years he -sends them eastward into the mountains. The forest Indian of the lower -Urubamba is a fisherman while the river is low and lives in a reed hut -beside his cultivated patch of cane and yuca. When the floods come he is -driven to the higher ground in the hills where he has another cultivated -patch of land and a rude shelter. To be sure, these are seasonal -migrations, yet through them the country becomes better known to each -new generation of men. And each generation supplies its pioneers, who -drift into the remoter places where population is scarce or altogether -wanting. - -[Illustration: FIG. 24--This stone hut, grass-thatched, is the highest -permanent habitation in Peru, and is believed to be the highest in the -world. Altitude of 17,100 feet (5,210 m.) determined by instrumental -survey. The general geographic relationships of the region in which the -hut is situated are shown in Fig. 25. For location see the topographic -map, Fig. 204.] - -Dry years and extremely dry years may have opposite effects. When -moderate dryness prevails the results may be endurable. The oases -become crowded with men and beasts just when they can ill afford to -support them. The alfalfa meadows become overstocked and cattle become -lean and almost worthless. But there is at least bare subsistence. By -contrast, if extreme and prolonged drought prevails, some of the people -are driven forth to more favored spots. At Vallenar in central Chile -some of the workmen in extreme years go up to the nitrate pampa; in wet -years they return. When the agents of the nitrate companies hear of hard -times in a desert valley they offer employment to the stricken people. -It not infrequently happens that when there are droughts in desert Chile -there are abundant rains in Argentina on the other side of the -Cordillera. There has therefore been for many generations an irregular -and slight, though definite, shifting of population from one side of the -mountains to the other as periods of drought and periods of rain -alternated in the two regions. Some think there is satisfactory evidence -to prove that a number of the great Mongolian emigrations took place in -wet years when pasture was abundant and when the pastoral nomad found it -easy to travel. On the other hand it has been urged that the cause of -many emigrations was prolonged periods of drought when the choice lay -between starvation and flight. It is evident from the foregoing that -both views may be correct in spite of the fact that identical effects -are attributed to opposite causes. - -[Illustration: FIG. 25--Regional diagram for the Maritime Cordillera to -show the physical relations in the district where the highest habitation -in the world are located. For location, see Fig. 20. It should be -remembered that the orientation of these diagrams is generalized. By -reference to Fig. 20 it will be seen that some portions of the crest of -the Maritime Cordillera run east and west and others north and south. -The same is true of the Cordillera Vilcapampa, Fig. 36.] - - _Note on regional diagrams._--For the sake of clearness I have - classified the accompanying facts of human distribution in the - country of the shepherds and represented them graphically in - “regional†diagrams, Figs. 17, 25, 26, 32, 34, 36, 42, 65. These - diagrams are constructed on the principle of dominant control. Each - brings out the factors of greatest importance in the distribution - of the people in a given region. Furthermore, the facts are - compressed within the limits of a small rectangle. This - compression, though great, respects all essential relations. For - example, every location on these diagrams has a concrete - illustration but the accidental relations of the field have been - omitted; the essential relations are preserved. Each diagram is, - therefore, a kind of generalized type map. It bears somewhat the - same relation to the facts of human geography that a block diagram - does to physiography. The darkest shading represents steep - snow-covered country; the next lower grade represents rough but - snow-free country; the lightest shading represents moderate relief; - unshaded parts represent plain or plateau. Small circles represent - forest or woodland; small open-spaced dots, grassland. Fine - alluvium is represented by small closely spaced dots; coarse - alluvium by large closely spaced dots. - - To take an illustration. In Figure 32 we have the Apurimac region - near Pasaje (see location map, Fig. 20). At the lower edge of the - rectangle is a snow-capped outlier of the Cordillera Vilcapampa. - The belt of rugged country represents the lofty, steep, exposed, - and largely inaccessible ridges at the mid-elevations of the - mountains below the glaciated slopes at the heads of tributary - valleys. The villages in the belt of pasture might well be - Incahuasi and Corralpata. The floors of the large canyons on either - hand are bordered by extensive alluvial fans. The river courses are - sketched in a diagrammatic way only, but a map would not be - different in its general disposition. Each location is justified by - a real place with the same essential features and relations. In - making the change there has been no alteration of the general - relation of the alluvial lands to each other or to the highland. By - suppressing unnecessary details there is produced a diagram whose - essentials have simple and clear relations. When such a regional - diagram is amplified by photographs of real conditions it becomes a - sort of generalized picture of a large group of geographic facts. - One could very well extend the method to the whole of South - America. It would be a real service to geography to draw up a set - of, say, twelve to fifteen regional diagrams, still further - generalized, for the whole of the continent. As a broad - classification they would serve both the specialist and the general - student. As the basis for a regional map of South America they - would be invaluable if worked out in sufficient detail and - constructed on the indispensable basis of field studies. - -It is still an open question whether security or insecurity is more -favorable for the broad distribution of the Peruvian Indians of the -mountain zone which forms the subject of this chapter. Certainly both -tend to make the remoter places better known. Tradition has it that, in -the days of intertribal conflict before the Conquest, fugitives fled -into the high mountain pastures and lived in hidden places and in caves. -Life was insecure and relief was sought in flight. On the other hand -peace has brought security to life. The trails are now safe. A shepherd -may drive his flock anywhere. He no longer has any one to fear in his -search for new pastures. It would perhaps be safe to conclude that there -is equally broad distribution of men in the mountain pastures in time of -peace and in time of war. There is, however, a difference in the kind -of distribution. In time of peace the individual is safe anywhere; in -time of unrest he is safe only when isolated and virtually concealed. By -contrast, the group living near the trails is scattered by plundering -bands and war parties. The remote and isolated group may successfully -oppose the smaller band and the individuals that might reach the remoter -regions. The fugitive group would have nothing to fear from large bands, -for the limited food supply would inevitably cause these to disintegrate -upon leaving the main routes of travel. Probably the fullest exploration -of the mountain pastures has resulted from the alternation of peace and -war. The opposite conditions which these establish foster both kinds of -distribution; hence both the remote group life encouraged by war and the -individual’s lack of restraint in time of peace are probably in large -part responsible for the present widespread occupation of the Peruvian -mountains. - -The loftiest habitation in the world (Fig. 24) is in Peru. Between -Antabamba and Cotahuasi occur the highest passes in the Maritime -Cordillera. We crossed at 17,400 feet (5,300 m.), and three hundred feet -lower is the last outpost of the Indian shepherds. The snowline, very -steeply canted away from the sun, is between 17,200 and 17,600 feet -(5,240 to 5,360 m.). At frequent intervals during the three months of -winter, snowfalls during the night and terrific hailstorms in the late -afternoon drive both shepherds and flocks to the shelter of leeward -slopes or steep canyon walls. At our six camps, between 16,000 and -17,200 feet (4,876 and 5,240 m.), in September, 1911, the minimum -temperature ranged from 4° to 20°F. The thatched stone hut that we -passed at 17,100 feet and that enjoys the distinction of being the -highest in the world was in other respects the same as the thousands of -others in the same region. It sheltered a family of five. As we passed, -three rosy-cheeked children almost as fat as the sheep about them were -sitting on the ground in a corner of the corral playing with balls of -wool. Hundreds of alpacas and sheep grazed on the hill slopes and valley -floor, and their tracks showed plainly that they were frequently driven -up to the snowline in those valleys where a trickle of water supported a -band of pasture. Less than a hundred feet below them were other huts and -flocks. - -Here we have the limits of altitude and the limits of resources. The -intervalley spaces do not support grass. Some of them are quite bare, -others are covered with mosses. It is too high for even the tola -bush--that pioneer of Alpine vegetation in the Andes. The distance[6] to -Cotahuasi is 75 miles (120 km.), to Antabamba 50 miles (80 km.). Thence -wool must be shipped by pack-train to the railroad in the one case 250 -miles (400 km.) to Arequipa, in the other case 200 miles (320 km.) to -Cuzco. Even the potatoes and barley, which must be imported, come from -valleys several days’ journey away. The question naturally arises why -these people live on the rim of the world. Did they seek out these -neglected pastures, or were they driven to them? Do they live here by -choice or of necessity? The answer to these questions introduces two -other geographic factors of prime importance, the one physical, the -other economic. - -The main tracts of lofty pasture above Antabamba cover mountain slopes -and valley floor alike, but the moist valley floors supply the best -grazing. Moreover, the main valleys have been intensively glaciated. -Hence, though their sides are steep walls, their floors are broad and -flat. Marshy tracts, periodically flooded, are scattered throughout, and -here and there are overdeepened portions where lakes have gathered. -There is a thick carpet of grass, also numerous huts and corrals, and -many flocks. At the upper edge of the main zone of pasture the grasses -become thin and with increasing altitude give out altogether except -along the moist valley floors or on shoulders where there is seepage. - -If the streams head in dry mountain slopes without snow the grassy bands -of the valley floor terminate at moderate elevations. If the streams -have their sources in snowfields or glaciers there is a more uniform -run-off, and a ribbon of pasture may extend to the snowline. To the -latter class belong the pastures that support these remote people. - -In the case of the Maritime Andes the great elevation of the snowline is -also a factor. If, in Figure 25, we think of the snowline as at the -upper level of the main zone of pasture then we should have the -conditions shown in Figure 36, where the limit of general, not local, -occupation is the snowline, as in the Cordillera Vilcapampa and between -Chuquibambilla and Antabamba. - -A third factor is the character of the soil. Large amounts of volcanic -ash and lapilli were thrown out in the late stages of volcanic eruption -in which the present cones of the Maritime Andes were formed. The coarse -texture of these deposits allows the ready escape of rainwater. The -combination of extreme aridity and great elevation results in a double -restraint upon vegetation. Outside of the moist valley floors, with -their film of ground moraine on whose surface plants find a more -congenial soil, there is an extremely small amount of pasture. Here are -the natural grazing grounds of the fleet vicuña. They occur in -hundreds, and so remote and little disturbed are they that near the main -pass one may count them by the score. As we rode by, many of them only -stared at us without taking the trouble to get beyond rifle shot. It is -not difficult to believe that the Indians easily shoot great numbers in -remote valleys that have not been hunted for years. - -The extreme conditions of life existing on these lofty plateaus are well -shown by the readiness with which even the hardy shepherds avail -themselves of shelter. Wherever deep valleys bring a milder climate -within reach of the pastures the latter are unpopulated for miles on -either side. The sixty-mile stretch between Chuquibamba and Salamanca is -without even a single hut, though there are pastures superior to the -ones occupied by those loftiest huts of all. Likewise there are no -permanent homes between Salamanca and Cotahuasi, though the shepherds -migrate across the belt in the milder season of rain. Eastward and -northward toward the crest of the Maritime Cordillera there are no huts -within a day’s journey of the Cotahuasi canyon. Then there is a group of -a dozen just under the crest of the secondary range that parallels the -main chain of volcanoes. Thence northward there are a number of -scattered huts between 15,500 and 16,500 feet (4,700 and 5,000 m.), -until we reach the highest habitations of all at 17,100 feet (5,210m.). - -[Illustration: FIG. 26--Regional diagram to show the physical relations -in the lava plateau of the Maritime Cordillera west of the continental -divide. For location, see Fig. 20. Trails lead up the intrenched -tributaries. If the irrigated bench (lower right corner) is large, a -town will be located on it. Shepherds’ huts are scattered about the edge -of the girdle of spurs. There is also a string of huts in the deep -sheltered head of each tributary. See also Fig. 29 for conditions on the -valley or canyon floor.] - -The unpopulated belts of lava plateau bordering the entrenched valleys -are, however, as distinctly “sustenance†spaces, to use Penck’s term, as -the irrigated and fertile alluvial fans in the bottom of the valley. -This is well shown when the rains come and flocks of llamas and sheep -are driven forth from the valleys to the best pastures. It is equally -well shown by the distribution of the shepherds’ homes. These are not -down on the warm canyon floor, separated by a half-day’s journey from -the grazing. They are in the intrenched tributary valleys of Figure 26 -or just within the rim of the canyon. It is not shelter from the cold -but from the wind that chiefly determines their location. They are also -kept near the rim of the canyon by the pressure of the farming -population from below. Every hundred feet of descent from the arid -plateau (Fig. 29) increases the water supply. Springs increase in number -and size; likewise belts of seepage make their appearance. The gradients -in many places diminish, and flattish spurs and shoulders interrupt the -generally steep descents of the canyon wall. Every change of this sort -has a real value to the farmer and means an enhanced price beyond the -ability of the poor shepherd to pay. If you ask a wealthy _hacendado_ on -the valley floor (Fig. 29), who it is that live in the huts above him, -he will invariably say “los Indios,†with a shrug meant to convey the -idea of poverty and worthlessness. Sometimes it is “los Indios pobres,†-or merely “los pobres.†Thus there is a vertical stratification of -society corresponding to the superimposed strata of climate and land. - -At Salamanca (Fig. 62) I saw this admirably displayed under -circumstances of unusual interest. The floor and slopes of the valley -are more completely terraced than in any other valley I know of. In the -photograph, Fig. 30, which shows at least 2,500 feet of descent near the -town, one cannot find a single patch of surface that is not under -cultivation. The valley is simply filled with people to the limit of its -capacity. Practically all are Indians, but with many grades of wealth -and importance. When we rode out of the valley before daybreak, one -September morning in 1911, there was a dead calm, and each step upward -carried us into a colder stratum of air. At sunrise we had reached a -point about 2,000 feet above the town, or 14,500 feet (4,420 m.) above -sea level. We stood on the frost line. On the opposite wall of the -valley the line was as clearly marked out as if it had been an -irrigating canal. The light was so fully reflected from the millions of -frost crystals above it that both the mountainside and the valley slopes -were sparkling like a ruffled lake at sunrise. Below the frost line the -slopes were dark or covered with yellow barley and wheat stubble or -green alfalfa. - -It happened that the frost line was near the line of division between -corn and potato cultivation and also near the line separating the steep -rough upper lands from the cultivable lower lands. Not a habitation was -in sight above us, except a few scattered miserable huts near broken -terraces, gullied by wet-weather streams and grown up to weeds and -brush. Below us were well-cultivated fields, and the stock was kept in -bounds by stone fences and corrals; above, the half-wild burros and -mules roamed about everywhere, and only the sheep and llamas were in -rude enclosures. Thus in a half hour we passed the frontier between the -agricultural folk below the frost line and the shepherd folk above it. - -[Illustration: FIG. 27--Terraced valley slopes at Huaynacotas, Cotahuasi -Valley, Peru. Elevation 11,500 feet (3,500 m.).] - -[Illustration: FIG. 28--The highly cultivated and thoroughly terraced -floor of the Ollantaytambo Valley at Ollantaytambo. This is a tributary -of the Urubamba; elevation, 11,000 feet.] - -[Illustration: FIG. 29--Cotahuasi on the floor of the Cotahuasi canyon. -The even skyline of the background is on a rather even-topped lava -plateau. The terrace on the left of the town is formed on limestone, -which is overlain by lava flows. A thick deposit of terraced alluvium -may be seen on the valley floor, and it is on one of the lower terraces -that the city of Cotahuasi stands. The higher terraces are in many cases -too dry for cultivation. The canyon is nearly 7,000 feet (2,130 m.) deep -and has been cut through one hundred principal lava flows.] - -In a few spots the line followed an irregular course, as where flatter -lands were developed at unusual elevations or where air drainage altered -the normal temperature. And at one place the frost actually stood on -the young corn, which led us to speculate on the possibility of securing -from Salamanca a variety of maize that is more nearly resistant to light -frosts than any now grown in the United States. In the endless and -largely unconscious experimentation of these folk perched on the valley -walls a result may have been achieved ahead of that yet reached by our -professional experimenters. Certain it is that nowhere else in the world -has the potato been grown under such severe climatic conditions as in -its native land of Peru and Bolivia. The hardiest varieties lack many -qualities that we prize. They are small and bitter. But at least they -will grow where all except very few cultivated plants fail, and they are -edible. Could they not be imported into Canada to push still farther -northward the limits of cultivation? Potatoes are now grown at Forts -Good Hope and McPherson in the lower Mackenzie basin. Would not the -hardiest Peruvian varieties grow at least as far north as the -continental timber line? I believe they could be grown still farther -north. They will endure repeated frosts. They need scarcely any -cultivation. Prepared in the Peruvian manner, as _chuño_, they could be -kept all winter. Being light, the meal derived from them could be easily -packed by hunters and prospectors. An Indian will carry in a pouch -enough to last him a week. Why not use it north of the continental limit -of other cultivated plants since it is the pioneer above the frost line -on the Peruvian mountains? - -The relation between farmer and shepherd or herdsman grows more complex -where deeper valleys interrupt the highlands and mountains. The -accompanying sketch, Fig. 32, represents typical relations, though based -chiefly on the Apurimac canyon and its surroundings near Pasaje. First -there is the snow-clad region at the top of the country. Below it are -grassy slopes, the homes of mountain shepherds, or rugged mountain -country unsuited for grazing. Still lower there is woodland, in patches -chiefly, but with a few large continuous tracts. The shady sides of the -ravines and the mountains have the most moisture, hence bear the densest -growths. Finally, the high country terminates in a second belt of -pasture below the woodland. - -[Illustration: FIG. 32--Regional diagram representing the deep canyoned -country west of the Eastern Cordillera in the region of the Apurimac. -For photograph see Fig. 94. For further description see note on regional -diagrams, p. 51. Numbers 1, 2, and 3 correspond in position to the same -numbers in Fig. 33.] - -[Illustration: FIG. 30--Terraced hill slopes near Salamanca. There is no -part of the photograph which is not covered with terraces save a few -places where bushy growths are visible or where torrents descend through -artificial canals.] - -[Illustration: FIG. 31--Alpine pastures in the mountain valley between -Chuquibambilla and Lambrama. Huge stone corrals are built on either -slope, sheltered from the night winds that blow down-valley.] - -Whenever streams descend from the snow or woodland country there is -water for the stock above and for irrigation on the alluvial fan below. -But the spur ends dropping off abruptly several thousand feet have a -limited area and no running streams, and the ground water is hundreds of -feet down. There is grass for stock, but there is no water. In some -places the stock is driven back and forth every few days. In a few -places water is brought to the stock by canal from the woodland streams -above, as at Corralpata.[7] In the same way a canal brings water to -Pasaje hacienda from a woodland strip many miles to the west. The little -canal in the figure is almost a toy construction a few inches wide and -deep and conveying only a trickle of water. Yet on it depends the -settlement at the spur end, and if it were cut the people would have to -repair it immediately or establish new homes. - -[Illustration: FIG. 33--Valley climates of the canyoned region shown in -Fig. 32.] - -The canal and the pasture are possible because the slopes are moderate. -They were formed in an earlier cycle of erosion when the land was lower. -They are hung midway between the rough mountain slopes above and the -steep canyon walls below (Fig. 32). Their smooth descents and gentle -profiles are in very pleasing contrast to the rugged scenery about them. -The trails follow them easily. Where the slopes are flattest, farmers -have settled and produce good crops of corn, vegetables, and barley. -Some farmers have even developed three-and four-story farms. On an -alluvial fan in the main valley they raise sugar cane and tropical and -subtropical fruits; on the flat upper slopes they produce corn; in the -moister soil near the edge of the woodland are fields of mountain -potatoes; and the upper pastures maintain flocks of sheep. In one -district this change takes place in a distance that may be covered in -five hours. Generally it is at least a full and hard day’s journey from -one end of the series to the other. - -Wherever these features are closely associated they tend to be -controlled by the planter in some deep valley thereabouts. Where they -are widely scattered the people are independent, small groups living in -places nearly inaccessible. Legally they are all under the control of -the owners of princely tracts that take in the whole country, but the -remote groups are left almost wholly to themselves. In most cases they -are supposed to sell their few commercial products to the _hacendado_ -who nominally owns their land, but the administration of this -arrangement is left largely to chance. The shepherds and small farmers -near the plantation are more dependent upon the planter for supplies, -and also their wants are more varied and numerous. Hence they pay for -their better location in free labor and in produce sold at a discount. - -So deep are some of the main canyons, like the Apurimac and the -Cotahuasi, that their floors are arid or semi-arid. The fortunes of -Pasaje are tied to a narrow canal from the moist woodland and a tiny -brook from a hollow in the valley wall. Where the water has thus been -brought down to the arable soil of the fans there are rich plantations -and farms. Elsewhere, however, the floor is quite dry and uncultivated. -In small spots here and there is a little seepage, or a few springs, or -a mere thread of water that will not support a plantation, wherefore -there have come into existence the valley herdsmen and shepherds. Their -intimate knowledge of the moist places is their capital, quite as much -as are the cattle and sheep they own. In a sense their lands are the -neglected crumbs from the rich man’s table. So we find the shepherd from -the hills invading the valleys just as the valley farmer has invaded the -country of the shepherd. - -[Illustration: FIG. 34--Regional diagram to show the typical physical -conditions and relations in an intermont basin in the Peruvian Andes. -The Cuzco basin (see Fig. 37) is an actual illustration; it should, -however, be emphasized that the diagram is not a “map†of that basin, -for whilst conditions there have been utilized as a basis, the -generalization has been extended to illustrate many basins.] - -The basin type of topography calls into existence a set of relations -quite distinct from either of those we have just described. Figure 34 -represents the main facts. The rich and comparatively flat floor of the -basin supports most of the people. The alluvial fans tributary thereto -are composed of fine material on their outer margin and of coarse stony -waste at their heads. Hence the valley farms also extend over the edges -of the fans, while only pasture or dense chaparral occupies the upper -portions. Finally there is the steep margin of the basin where the -broad and moderate slopes of the highland break down to the floor of the -basin. - -[Illustration: FIG. 35--Climatic cross-section showing the location of -various zones of cultivation and pasture in a typical intermont basin in -the Peruvian Andes. The thickness of the dark symbols on the right is -proportional to the amount of each staple that is produced at the -corresponding elevation. See also the regional diagram Fig. 34.] - -If a given basin lies at an elevation exceeding 14,000 feet (4,270 m.), -there will be no cultivation, only pasture. If at 10,000 or 11,000 feet -(3,000 or 3,350 m.), there will be grain fields below and potato fields -above (Figs. 34 and 35). If still lower, fruit will come in and finally -sugar cane and many other subtropical products, as at Abancay. Much will -also depend upon the amount of available water and the extent of the -pasture land. Thus the densely populated Cuzco basin has a vast mountain -territory tributary to it and is itself within the limits of barley and -wheat cultivation. Furthermore there are a number of smaller basins, -like the Anta basin on the north, which are dependent upon its better -markets and transportation facilities. A dominance of this kind is -self-stimulating and at last is out of all proportion to the original -differences of nature. Cuzco has also profited as the gateway to the -great northeastern valley region of the Urubamba and its big -tributaries. All of the varied products of the subtropical valleys find -their immediate market at Cuzco. - -The effect of this natural conspiracy of conditions has been to place -the historic city of Cuzco in a position of extraordinary importance. -Hundreds of years before the Spanish Conquest it was a center of -far-reaching influence, the home of the powerful Inca kings. From it the -strong arm of authority and conquest was extended; to it came tribute -of grain, wool, and gold. To one accustomed to look at such great -consequences as having at least some ultimate connection with the earth, -the situation of Cuzco would be expected to have some unique features. -With the glorious past of that city in mind, no one can climb to the -surrounding heights and look down upon the fertile mountain-rimmed plain -as at an ordinary sight (Fig. 37). The secret of those great conquests -lies not only in mind but in matter. If the rise of the Incas to power -was not related to the topography and climate of the Cuzco basin, at -least it is certain that without so broad and noble a stage the scenes -would have been enacted on a far different scale. - -The first Inca king and the Spanish after the Incas found here no mobile -nomadic tribes melting away at the first touch, no savages hiding in -forest fastnesses, but a well-rooted agricultural race in whose center a -large city had grown up. Without a city and a fertile tributary plain no -strong system of government could be maintained or could even arise. It -is a great advantage in ruling to have subjects that cannot move. The -agricultural Indians of the Andean valleys and basins, in contrast to -the mobile shepherd, are as fixed as the soil from which they draw their -life. - -The full occupation of the pasture lands about the Cuzco basin is in -direct relation to the advantages we have already enumerated. Every part -of the region feels the pressure of population. Nowhere else in the -Peruvian Andes are the limits between cultivation and grazing more -definitely drawn than here. Moreover, there is today a marked difference -between the types that inhabit highland and basin. The basin Indian is -either a debauched city dweller or, as generally, a relatively alert -farmer. The shepherds are exceedingly ignorant and live for the most -part in a manner almost as primitive as at the time of the Conquest. -They are shy and suspicious. Many of them prefer a life of isolation and -rarely go down to the town. They live on the fringe of culture. The new -elements of their life have come to them solely by accident and by what -might be called a process of ethnic seepage. The slight advances that -have been made do not happen by design, they merely happen. Put the -highland shepherd in the basin and he would starve in competition with -the basin type. Undoubtedly he would live in the basin if he could. He -has not been driven out of the basin; he is kept out. - -And thus it is around the border of the Abancay basin and others like -it. Only, the Abancay basin is lower and more varied as to resources. -The Indian is here in competition with the capitalistic white planter. -He lives on the land by sufferance alone. Farther up the slopes are the -farms of the Indians and above them are the pastures of the ignorant -shepherds. Whereas the Indian farmer who raises potatoes clings chiefly -to the edge of the Cuzco basin where lie the most undesirable -agricultural lands, the Indian farmers of Abancay live on broad rolling -slopes like those near the pass northward toward Huancarama. They are -unusually prosperous, with fields so well cultivated and fenced, so -clean and productive, that they remind one somewhat of the beautiful -rolling prairies of Iowa. - -It remains to consider the special topographic features of the mountain -environments we are discussing, in the Vilcapampa region on the eastern -border of the Andes (Fig. 36). The Cordillera Vilcapampa is -snow-crested, containing a number of fine white peaks like Salcantay, -Soray, and Soiroccocha (Fig. 140). There are many small glaciers and a -few that are several miles long. There was here in glacial times a much -larger system of glaciers, which lived long enough to work great changes -in the topography. The floors of the glaciated valleys were smoothed and -broadened and their gradients flattened (Figs. 137 and 190). The side -walls were steepened and precipitous cirques were formed at the valley -heads. Also, there were built across the valleys a number of stony -morainic ridges. With all these changes there was, however, but little -effect upon the main masses of the big intervalley spurs. They remain as -before--bold, wind-swept, broken, and nearly inaccessible. - -[Illustration: FIG. 36--Regional diagram for the Eastern Cordillera or -Cordillera Vilcapampa. Note the crowded zones on the right (east and -north) in contrast to the open succession on the left. In sheltered -places woodland extends even higher than shown. At several points -patches of it grow right under the snowline. Other patches grow on the -floors of the glaciated valley troughs.] - -The work of the glaciers aids the mountain people. The stony moraines -afford them handy sizable building material for their stone huts and -their numerous corrals. The thick tufts of grass in the marshy spots in -the overdeepened parts of the valleys furnish them with grass for their -thatched roofs. And, most important of all, the flat valley floors have -the best pasture in the whole mountain region. There is plenty of water. -There is seclusion, and, if a fence be built from one valley wall to -another as can be done with little labor, an entire section of the -valley may be inclosed. A village like Choquetira, located on a bench on -the valley side, commands an extensive view up and down the valley--an -important feature in a grazing village where the corrals cannot always -be built near the houses of the owners. Long, finger-like belts of -highland-shepherd population have thus been extended into the mountain -valleys. Sheep and llamas drift right up to the snowline. - -There is, however, a marked difference between the people on opposite -sides of the Cordillera Vilcapampa. On the west the mountains are -bordered by a broad highland devoted to grazing. On the east there is a -narrower grazing belt leading abruptly down to tropical valleys. The -eastern or leeward side is also the warmer and wetter side of the -Cordillera. The snowline is several hundred feet lower on the east. The -result is that patches of scrub and even a little woodland occur almost -at the snowline in favored places. Mist and storms are more frequent. -The grass is longer and fresher. Vegetation in general is more abundant. -The people make less of wool than of cattle, horses, and mules. -Vilcabamba pueblo is famous for its horses, wiry, long-haired little -beasts, as hardy as Shetland ponies. We found cattle grazing only five -hundred feet below the limit of perpetual snow. There are cultivated -spots only a little farther down, and only a thousand feet below the -snow are abandoned terraces. At the same elevation are twisted quenigo -trees, at least two hundred years old, as shown by their rings of -growth. Thus the limits of agriculture are higher on the east; likewise -the limits of cattle grazing that naturally goes with agriculture. Sheep -would thrive, but llamas do better in drier country, and the shepherd -must needs mix his flocks, for the wool which is his chief product -requires transportation and only the cheap and acclimated llama is at -the shepherd’s disposal. From these facts it will be seen that the -anthropo-geographic contrasts between the eastern and western sides of -the Cordillera Vilcapampa are as definite as the climatic and vegetal -contrasts. This is especially well shown in the differences between dry -Arma, deep-sunk in a glaciated valley west of the crest of the -mountains, and wet Puquiura, a half-day’s journey east of the crest. -There is no group on the east at all comparable to the shepherds of -Choquetira, either in the matter of thorough-going dependence upon -grazing or in that of dependence upon glacial topography. - -[Illustration: FIG. 37--Cuzco and a portion of the famous Cuzco basin -with bordering grassy highlands.] - -[Illustration: FIG. 38--Terraced valley slopes and floor, Urubamba -Valley between Urubamba and Ollantaytambo.] - -[Illustration: FIG. 39--Huichihua, near Chuquibambilla, a typical -mountain village, in the valleys of the Central Ranges, Peruvian Andes.] - -[Illustration: FIG. 40--Potato fluid above Vilcabamba at 12,000 feet -(3,660 m.). The natural sod is broken by a steel-shod stick and the seed -potato dropped into a mere puncture. It receives no attention thereafter -until harvest time.] - -Topography is not always so intimately related to the life of the people -as here. In our own country the distribution of available water is a far -greater factor. The Peruvian Andes therefore occupy a distinctive place -in geography, since, more nearly than in most mountains, their physical -conditions have typical human relations that enable one clearly to -distinguish the limits of control of each feature of climate or relief. - - - - -CHAPTER VI - -THE BORDER VALLEYS OF THE EASTERN ANDES - - -[Illustration: FIG. 41--Regional diagram of the eastern aspect of the -Cordillera Vilcapampa. See also Fig. 17 of which this is an enlarged -section.] - -On the northeastern border of the Peruvian Andes long mountain spurs -trail down from the regions of snow to the forested plains of the -Amazon. Here are the greatest contrasts in the physical and human -geography of the Andean Cordillera. So striking is the fact that every -serious student of Peru finds himself compelled to cross and recross -this natural frontier. The thread of an investigation runs irregularly -now into one border zone, now into another. Out of the forest came the -fierce marauders who in the early period drove back the Inca pioneers. -Down into the forest to escape from the Spaniards fled the last Inca and -his fugitive court. Here the Jesuit fathers sowed their missions along -the forest margin, and watched over them for two hundred years. From the -mountain border one rubber project after another has been launched into -the vast swampy lowlands threaded by great rivers. As an ethnic boundary -the eastern mountain border of Peru and Bolivia has no equal elsewhere -in South America. From the earliest antiquity the tribes of the -grass-covered mountains and the hordes of the forested plains have had -strongly divergent customs and speech, that bred enduring hatred and led -to frequent and bloody strife. - -[Illustration: FIG. 42--Rug weaver at Cotahuasi. The industry is limited -to a small group of related families, living in the Cotahuasi Canyon -near Cotahuasi. The rugs are made of alpaca wool. Pure black, pure -white, and various shades of mixed gray wool are employed. The result is -that the rugs have “fast†colors that always retain their original -contrasts. They are made only to order at the homes of the purchasers. -The money payment is small, but to it is added board and lodging, -besides tobacco, liqueurs, and wine. Before drinking they dip their -finger-tips in the wine and sprinkle the earth “that it may be -fruitful,†the air “that it may be warm,†the rug “that it may turn out -well,†and finally themselves, making the sign of the cross. Then they -set to work.] - -[Illustration: FIG. 43--The floor of the Urubamba Valley from Tarai. The -work of the glaciers was not confined to the lofty situations. Mountain -débris was delivered to all the streams, many of which aggraded their -floors to a depth of several hundred feet, thus increasing the extent of -arable soil at elevations where a less rigorous climate permits the -production of crops and encourages intensive cultivation.] - -On the steepest spurs of the Pampaconas Valley the traveler may go from -snow to pasture in a half day and from pasture to forest in the same -time. Another day he is in the hot zone of the larger valley floors, the -home of the Machigangas. The steep descents bring out the superimposed -zones with diagrammatic simplicity. The timber line is as sharply marked -as the edge of a cultivated field. At a point just beyond the huts of -Pampaconas one may stand on a grassy spur that leads directly up--a -day’s journey--to the white summits of the Cordillera Vilcapampa. Yet so -near him is the edge of the forest that he is tempted to try to throw a -stone into it. In an hour a bitter wind from the mountains may drive him -to shelter or a cold fog come rolling up from the moist region below. It -is hard to believe that oppressive heat is felt in the valley just -beneath him. - -In the larger valleys the geographic contrasts are less sharp and the -transition from mountains to plain, though less spectacular, is much -more complex and scientifically interesting. The forest types -interfinger along the shady and the sunny slopes. The climate is so -varied that the forest takes on a diversified character that makes it -far more useful to man. The forest Indians and the valley planters are -in closer association. There are many islands and peninsulas of plateau -population on the valley floor. Here the zones of climate and the belts -of fertile soil have larger areas and the land therefore has greater -economic value. Much as the valley people need easier and cheaper -communication with the rest of Peru it is no exaggeration to say that -the valley products, are needed far more by the coast and plateau -peoples to make the republic self-supporting. Coca, wood, sugar, fruit, -are in such demand that their laborious and costly transportation from -the valleys to the plateau is now carried on with at least some profit -to the valley people. Improved transportation would promote travel and -friendship and supply a basis for greater political unity. - -A change in these conditions is imminent. Years ago the Peruvian -government decreed the construction of a railway from Cuzco to Santa Ana -and preliminary surveys were made but without any immediate practical -effect. By June, 1914, 12.4 miles (20 km.) had been opened to traffic. -The total length of the proposed line is 112 miles (180 km.), the gauge -is to be only 2.46 feet (75 cm.),[8] and the proposed cost several -millions of dollars. The financial problem may be solved either by a -diversion of local revenues, derived from taxes on coca and alcohol, or -by borrowed foreign capital guaranteed by local revenues. - -A shrubby vegetation is scattered along the valley from the village of -Urubamba, 12,000 feet (3,658 m.) above sea level, to the Canyon of -Torontoy. It is local and of little value. Trees appear at -Ollantaytambo, 11,000 feet (3,353 m.), and here too are more extensive -wheat and maize fields besides throngs of cacti and great patches of -wild geraniums. On our valley journey we camped in pleasant fields -flanked by steep hills whose summits each morning were tipped with snow. -Enormous alluvial fans have partly filled up the valleys and furnished -broad tracts of fertile soil. The patient farmers have cleared away the -stones on the flatter portions and built retaining walls for the smooth -fields required for irrigation. In places the lower valley slopes are -terraced in the most regular manner (Fig. 38). Some of the fans are too -steep and stony for cultivation, exposing bare tracts which wash down -and cover the fields. Here and there are stone walls built especially to -retain the rush of mud and stones that the rains bring down. Many of -them were overthrown or completely buried. Unless the stream channels on -the fans are carefully watched and effective works kept up, the labor of -years may be destroyed in a single slide from the head of a steep fan. - -Each group of fans has a population proportioned to its size and -fertility. If there are broad expanses a town like Urubamba or a great -hacienda like Huadquiña is sure to be found. One group of huge stony -fans below Urubamba (Fig. 180) has only a thin population, for the soil -is coarse and infertile and the rivers deeply intrenched. In some places -the tiny fans perched high upon the flanks of the mountains where little -tributaries burst out of steep ravines are cultivated by distant owners -who also till parts of the larger fans on the main valley floors. -Between the fans of the valley bottoms and the smooth slopes of the high -plateaus are the unoccupied lands--the steep canyon walls. Only in the -most highly favored places where a small bench or a patch of alluvium -occurs may one find even an isolated dwelling. The stair-like trails, in -some places cut in solid rock, zigzag up the rocky slopes. An ascent of -a thousand feet requires about an hour’s travel with fresh beasts. The -valley people are therefore walled in. If they travel it is surely not -for pleasure. Even business trips are reduced to the smallest number. -The prosperity and happiness of the valley people are as well known -among the plateau people as is their remarkable bread. Their climate has -a combination of winter rain and winter cold with light frosts that is -as favorable for good wheat as the continuous winter cold and snow cover -of our northern Middle West. The colder grainfields of the plateau are -sowed to barley chiefly, though there is also produced some wheat. -Urubamba wheat and bread are exported in relatively large quantities, -and the market demands greater quantities than the valley can supply. -Oregon and Washington flour are imported at Cuzco, two days’ muleback -journey from the wheat fields of Urubamba. - -Such are the conditions in the upper Urubamba Valley. The lower valley, -beginning at Huadquiña, is 8,000 feet (2,440 m.) above sea level and -extends down to the two-thousand-foot contour at Rosalina and to one -thousand feet (305 m.) at Pongo de Mainique. The upper and lower -sections are only a score of miles (30 km.) apart between Huadquiña and -Torontoy, but there is a difference in elevation of three thousand feet -(915 m.) at just the level where the maximum contrasts are produced. The -cold timber line is at 10,500 feet (3,200 m.).[9] Winter frosts are -common at the one place; they are absent altogether at the other. -Torontoy produces corn; Huadquiña produces sugar cane. - -These contrasts are still further emphasized by the sharp topographic -break between the two unlike portions of the valley. A few miles below -Torontoy the Urubamba plunges into a mile-deep granite canyon. The walls -are so close together that it is impossible from the canyon floor to get -into one photograph the highest and steepest walls. At one place there -is over a mile of descent in a horizontal distance of 2,000 feet. Huge -granite slabs fall off along joint planes inclined but 15° from the -vertical. The effect is stupendous. The canyon floor is littered with -coarse waste and the gradient of the river greatly steepened. There is -no cultivation. The trees cling with difficulty to patches of rock waste -or to the less-inclined slopes. There is a thin crevice vegetation that -outlines the joint pattern where seepage supplies the venturesome roots -with moisture. Man has no foothold here, save at the top of the country, -as at Machu Picchu, a typical fortress location safeguarded by the -virtually inaccessible canyon wall and connected with the main ridge -slopes only by an easily guarded narrow spur. Toward the lower end of -the canyon a little finer alluvium appears and settlement begins. -Finally, after a tumble of three thousand feet over countless rapids the -river emerges at Colpani, where an enormous mass of alluvium has been -dumped. The well-intrenched river has already cut a large part of it -away. A little farther on is Huadquiña in the Salcantay Valley, where a -tributary of the Urubamba has built up a sheet of alluvial land, bright -green with cane. From the distant peaks of Salcantay and its neighbors -well-fed streams descend to fill the irrigation channels. Thus the snow -and rock-waste of the distant mountains are turned into corn and sugar -on the valley lowlands. - -[Illustration: FIG. 44--The snow-capped Cordillera Vilcapampa north of -Yucay and the upper canyon of the Urubamba from the wheat fields near -Chinchero. In the foreground is one of the well-graded mature slopes of -Fig. 123. The crests of the mountains lie along the axis of a granite -intrusion. The extent of the snowfields is extraordinary in view of the -low latitude, 13° S.] - -[Illustration: FIG. 45--Rounded slopes due to glacial action at -Pampaconas in the Pampaconas Valley near Vilcabamba. A heavy tropical -forest extends up the Pampaconas Valley to the hill slopes in the -background. Its upper limit of growth is about 10,000 feet (3,050 m.). -The camera is pointed slightly downhill.] - -[Illustration: FIG. 46--Hacienda Huadquiña in the Salcantay Valley a -short distance above its junction with the Urubamba, elevation 8,000 -feet (2,440 m.). The cultivated fields are all planted to sugar cane. -The mountain slopes are devoted to grazing.] - -The Cordillera Vilcapampa is a climatic as well as a topographic -barrier. The southwestern aspect is dry; the northeastern aspect -forested. The gap of the canyon, it should be noticed, comes at a -critical level, for it falls just above the upper border of the zone of -maximum precipitation. The result is that though mists are driven -through the canyon by prolonged up-valley winds, they scatter on -reaching the plateau or gather high up on the flanks of the valley or -around the snowy peaks overlooking the trail between Ollantaytambo and -Urubamba. The canyon walls are drenched with rains and even some of the -lofty spurs are clothed with dense forest or scrub. - -Farther down the valley winds about irregularly, now pushed to one side -by a huge alluvial fan, now turned by some resistant spur of rock. -Between the front range of the Andes and the Cordillera Vilcapampa there -is a broad stretch of mountain country in the lee of the front range -which rises to 7,000 feet (2,134 m.) at Abra Tocate (Fig. 15), and falls -off to low hills about Rosalina. It is all very rough in that there are -nowhere any flats except for the narrow playa strips along the streams. -The dense forest adds to the difficulty of movement. In general -appearance it is very much like the rugged Cascade country of Oregon -except that the Peruvian forest is much more patchy and its trees are in -many places loaded with dense dripping moss which gives the landscape a -somber touch quite absent from most of the forests of the temperate -zone. - -The fertility of the eastern valleys of Peru--the result of a union of -favorable climate and alluvial soil--has drawn the planter into this -remote section of the country, but how can he dispose of his products? -Even today with a railway to Cuzco from the coast it is almost -impossible for him to get his sugar and cacao to the outside world.[10] -How did he manage before even this railway was built? How could the -eastern valley planter live before there were any railways at all in -Peru? In part he has solved the problem as the moonshiner of Kentucky -tried to solve it, and from cane juice makes aguardiente (brandy). The -latter is a much more valuable product than sugar, hence (1) it will -bear a higher rate of transportation, or (2) it will at the same rate of -transportation yield a greater net profit. In a remote valley where -sugar could not be exported on account of high freight rates brandy -could still be profitably exported. - -The same may be said for coca and cacao. They are condensed and valuable -products. Both require more labor than sugar but are lighter in bulk and -thus have to bear, in proportion to their value, a smaller share of the -cost of transportation. At the end of three years coca produces over a -ton of leaves per acre per year, and it can be made to produce as much -as two tons to the acre. The leaves are picked four times a year. They -are worth from eight to twelve cents gold a pound at the plantation or -sixteen cents a pound at Cuzco. An orchard of well-cultivated and -irrigated cacao trees will do even better. Once they begin to bear the -trees require relatively little care except in keeping out weeds and -brush and maintaining the water ditches. However, the pods must be -gathered at just the right time, the seeds must be raked and dried with -expert care, and after that comes the arduous labor of the grinding. -This is done by hand on an inclined plane with a heavy round stone whose -corners fit the hand. The chocolate must then be worked into cakes and -dried, or it must be sacked in heavy cowhide and sewed so as to be -practically air tight. When eight or ten years old the trees are mature -and each may then bear a thousand pounds of seed. - -[Illustration: FIG. 47--The Urubamba Valley below Paltaybamba. Harder -rocks intruded into the schists that in general compose the valley walls -here form steep scarps. It has been suggested (Davis) that such a -constricted portion of a valley be called a “shut-in.†The old trail -climbed to the top of the valley and over the back of a huge spur. The -new road is virtually a tunnel blasted along the face of a cliff.] - -[Illustration: FIG 48--Coca seed beds near Quillabamba, Urubamba Valley. -The young plants are grown under shade and after attaining a height of a -foot or more are gradually accustomed to sunlight and finally -transplanted to the fields that are to become coca orchards.] - -If labor were cheap and abundant the whole trend of tropical agriculture -in the eastern valleys would be toward intensive cultivation and the -production of expensive exports. But labor is actually scarce. Every -planter must have agents who can send men down from the plateau towns. -And the planter himself must use his labor to the best advantage. -Aguardiente requires less labor than cacao and coca. The cane costs -about as much in labor the first year as the coca bush or the cacao -tree, but after that much less. The manufacture of brandy from the cane -juice requires little labor though much expensive machinery. For -chocolate, a storehouse, a grinding stone, and a rake are all that -are required. So the planter must work out his own salvation -individually. He must take account of the return upon investments in -machinery, of the number of hands he can command from among the “faena†-or free Indians, of the cost and number of imported hands from the -valley and plateau towns, and, finally, of the transportation rates -dependent upon the number of mules in the neighborhood, and distance -from the market. If in addition the labor is skilfully employed so as to -have the tasks which the various products require fall at different -periods of the year, then the planter may expect to make money upon his -time and get a return upon his initial investment in the land.[11] - -[Illustration: FIG. 49--Fig tree formerly attached to a host but now -left standing on its stilt-like aërial roots owing to the decay of the -host.] - -[Illustration: FIG. 50--A tiny rubber plant is growing under the tripod -made of yuca stems tied with banana leaves. Growing yuca is shown by the -naked stalks to the left and right of this canopy, and banana plants -fill the background. A plantation scene at Echarati.] - -The type of tropical agriculture which we have outlined is profitable -for the few planters who make up the white population of the valleys, -but it has a deplorable effect upon the Indian population. Though the -planters, one and all, complain bitterly of the drunken habits of their -laborers, they themselves put into the hands of the Indians the means of -debauchery. Practically the whole production of the eastern valleys is -consumed in Peru. What the valleys do not take is sent to the plateau, -where it is the chief cause of vicious conduct. Two-thirds of the -prisoners in the city jails are drunkards, and, to be quite plain, they -are virtually supplied with brandy by the planter, who could not -otherwise make enough money. So although the planter wants more and -better labor he is destroying the quality of the little there is, and, -if not actually reducing the quantity of it, he is at least very -certainly reducing the rate of increase. - -The difficulties of the valley planter could be at least partly overcome -in several ways. The railway will reduce transportation costs, -especially when the playas of the valleys are all cleared and the -exports increased. Moreover the eastern valleys are capable of -producing things of greater utility than brandy and coca leaves. So far -as profits are increased by cheaper transportation we may expect the -planter to produce more rather than less of brandy and coca, his two -most profitable exports, unless other products can be found that are -still more profitable. The ratio of profits on sugar and brandy will -still be the same unless the government increases the tax on brandy -until it becomes no more profitable than sugar. That is what ought to be -done for the good of the Indian population. It cannot be done safely -without offering in its place the boon of cheaper railway transportation -for the sugar crop. Furthermore, with railway improvements should go the -blessings that agricultural experiments can bestow. A government farm in -a suitable place would establish rice and cotton cultivation. Many of -the playas or lower alluvial lands along the rivers can be irrigated. -Only a small fraction of the water of the Rio Urubamba is now turned out -upon the fields. For a large part of the year the natural rainfall would -suffice to keep rice in good condition. Six tons a year are now grown on -Hacienda Sahuayaco for local use on account of the heavy rate on rice -imported on muleback from Cuzco, whither it comes by sea and by trail -from distant coastal valleys. The lowland people also need rice and it -could be sent to them down river by an easier route than that over which -their supplies now come. It should be exported to the highlands, not -imported therefrom. There are so many varieties adapted to so many kinds -of soil and climate that large amounts should be produced at fair -profits. - -The cotton plant, on the other hand, is more particular about climate -and especially the duration of dry and wet seasons; in spite of this its -requirements are all met in the Santa Ana Valley. The rainfall is -moderate and there is an abundance of dry warm soil. The plant could -make most of its growth in the wet season, and the four months of cooler -dry season with only occasional showers would favor both a bright staple -and a good picking season. More labor would be required for cotton and -rice and for the increased production of cacao than under the present -system. This would not be a real difficulty if the existing labor -supply were conserved by the practical abolition, through heavy -taxation, of the brandy that is the chief cause of the laborer’s vicious -habits. This is the first step in securing the best return upon the -capital invested in a railway. Economic progress is here bound up with a -very practical morality. Colonization in the eastern valleys, of which -there have been but a few dismal attempts, will only extend the field of -influence, it will not solve the real problem of bringing the people of -the rich eastern territory of Peru into full and honorable possession of -their natural wealth. - -The value of the eastern valleys was known in Inca times, for their -stone-faced terraces and coca-drying patios may still be seen at -Echarati and on the border of the Chaupimayu Valley at Sahuayaco. -Tradition has it that here were the imperial coca lands, that such of -the forest Indians as were enslaved were obliged to work upon them, and -that the leaves were sent to Cuzco over a paved road now covered with -“montaña†or forest. The Indians still relate that at times a -mysterious, wavering, white light appears on the terraces and hills -where old treasure lies buried. Some of the Indians have gold and silver -objects which they say were dug from the floors of hill caves. There -appears to have been an early occupation of the best lands by the -Spaniards, for the long extensions down them of Quechua population upon -which the conquerors could depend no doubt combined with the special -products of the valley to draw white colonists thither.[12] General -Miller,[13] writing in 1836, mentions the villages of Incharate -(Echarati) and Sant’ Ana (Santa Ana) but discourages the idea of -colonization “... since the river ... has lofty mountains on either -side of it, and is not navigable even for boats.†- -In the “Itinerario de los viajes de Raimondi en el Peruâ€[14] there is an -interesting account of the settlement by the Rueda family of the great -estate still held by a Rueda, the wife of Señor Duque. José Rueda, in -1829, was a government deputy representative and took his pay in land, -acquiring valuable territory on which there was nothing more than a -mission. In 1830 Rueda ceded certain lands in “arriendo†(rent) and on -these were founded the haciendas Pucamoco, Sahuayaco, etc. - -Señor Gonzales, the present owner of Hacienda Sahuayaco, recently -obtained his land--a princely estate, ten miles by forty--for 12,000 -soles ($6,000). In a few years he has cleared the best tract, built -several miles of canals, hewed out houses and furniture, planted coca, -cacao, cane, coffee, rice, pepper, and cotton, and would not sell for -$50,000. Moreover, instead of being a superintendent on a neighboring -estate and keeping a shop in Cuzco, where his large family was a source -of great expense, he has become a wealthy landowner. He has educated a -son in the United States. He is importing machinery, such as a rice -thresher and a distilling plant. His son is looking forward to the -purchase of still more playa land down river. He pays a sol a day to -each laborer, securing men from Cotabambas and Abancay, where there are -many Indians, a low standard of wages, little unoccupied land, and a hot -climate, so that the immigrants do not need to become acclimatized. - -The deepest valleys in the Eastern Andes of Peru have a semi-arid -climate which brings in its train a variety of unusual geographic -relations. At first as one descends the valley the shady and sunny -slopes show sharply contrasted vegetation. - -[Illustration: FIG. 51--Robledo’s mountain-side trail in the Urubamba -Valley below Rosalina.] - -[Illustration: FIG. 52--An epiphyte partly supported by a dead host at -Rosalina, elevation 2,000 feet. The epiphyte bears a striking -resemblance to a horned beast whose arched back, tightly clasped -fingers, and small eyes give it a peculiarly malignant and life-like -expression.] - -[Illustration: FIG. 53A--The smooth grassy slopes at the junction of the -Yanatili (left) and Urubamba (right) rivers near Pabellon.] - -[Illustration: FIG. 53B--Distribution of vegetation in the Urubamba -Valley near Torontoy. The patches of timber in the background occupy the -shady sides of the spurs; the sunny slopes are grass-covered; the valley -floor is filled with thickets and patches of woodland but not true -forest.] - -The one is forested, the other grass-covered. Slopes that receive the -noon and afternoon sun the greater part of the year are hottest and -therefore driest. For places in 11° south latitude the sun is well to -the north six months of the year, nearly overhead for about two months, -and to the south four months. Northwesterly aspects are therefore driest -and warmest, hence also grass-covered. In many places the line between -grass and forest is developed so sharply that it seems to be the -artificial edge of a cut-over tract. This is true especially if the -relief is steep and the hill or ridge-crests sharp.[15] - -[Illustration: FIG. 54--Climatic cross-section from the crest of the -Cordillera Vilcapampa down the eastern mountain valleys to the tropical -plains.] - -At Santa Ana this feature is developed in an amazingly clear manner, and -it is also combined with the dry timber line and with productivity in a -way I have never seen equaled elsewhere. The diagram will explain the -relation. It will be seen that the front range of the mountains is high -enough to shut off a great deal of rainfall. The lower hills and ridges -just within the front range are relatively dry. The deep valleys are -much drier. Each broad expansion of a deep valley is therefore a dry -pocket. Into it the sun pours even when all the surrounding hills and -mountains are wrapped in cloud. The greater number of hours of sunshine -hastens the rate of evaporation and still further increases the dryness. -Under the spur of much sunlight and of ample irrigation water from the -wetter hill slopes, the dry valley pockets produce huge crops of fruit -and cane. - -The influence of the local climate upon tree growth is striking. Every -few days, even in the relatively dry winter season, clouds gather about -the hills and there are local showers. The lower limit of the zone of -clouds is sharply marked and at both Santa Ana and Echarati it is -strikingly constant in elevation--about five thousand feet above sea -level. From the upper mountains the forest descends, with only small -patches of glade and prairie. At the lower edge of the zone of cloud it -stops abruptly on the warmer and drier slopes that face the afternoon -sun and continues on the moister slopes that face the forenoon sun or -that slope away from the sun. - -But this is not the only response the vegetation makes. The forest -changes in character as well as in distribution. The forest in the wet -zone is dense and the undergrowth luxuriant. In the selective slope -forest below the zone of cloud the undergrowth is commonly thin or -wanting and the trees grow in rather even-aged stands and by species. -Finally, on the valley floor and the tributary fans, there is a distinct -growth of scrub with bands of trees along the water courses. Local -tracts of coarse soil, or less rain on account of a deep “hole†in a -valley surrounded by steeper and higher mountains, or a change in the -valley trend that brings it into less free communication with the -prevailing winds, may still further increase the dryness and bring in a -true xerophytic or drought-resisting vegetation. Cacti are common all -through the Santa Ana Valley and below Sahuayaco there is a patch of -tree cacti and similar forms several square miles in extent. Still -farther down and about half-way between Sahuayaco and Pabellon are -immense tracts of grass-covered mountain slopes (Fig. 53). These extend -beyond Rosalina, the last of them terminating near Abra Tocate (Fig. -15). The sudden interruption is due to a turn in the valley giving -freer access to the up-valley winds that sweep through the pass at Pongo -de Mainique. - -[Illustration: FIG. 55--Map to show the relation of the grasslands of -the dry lower portion of the Urubamba Valley (unshaded) to the forested -lands at higher elevations (shaded). See Fig. 54 for climatic -conditions. Patches and slender tongues of woodland occur below the main -timber line and patches of grassland above it.] - -Northward from Abra Tocate (Fig. 55) the forest is practically -continuous. The break between the two vegetal regions is emphasized by a -corral for cattle and mules, the last outpost of the plateau herdsmen. -Not three miles away, on the opposite forested slope of the valley, is -the first of the Indian clearings where several families of Machigangas -spend the wet season when the lower river is in flood (Fig. 21). The -grass lands will not yield corn and coca because the soil is too thin, -infertile, and dry. The Indian farms are therefore all in the forest and -begin almost at its very edge. Here finally terminates a long peninsula -of grass-covered country. Below this point the heat and humidity rapidly -increase; the rains are heavier and more frequent; the country becomes -almost uninhabitable for stock; transportation rates double. Here is the -undisputed realm of the forest with new kinds of trees and products and -a distinctive type of forest-dwelling Indian. - -At the next low pass is the skull of an Italian who had murdered his -companions and stolen a season’s picking of rubber, attempting to escape -by canoe to the lower Urubamba from the Pongo de Mainique. The -Machigangas overtook him in their swiftest dugouts, spent a night with -him, and the next morning shot him in the back and returned with their -rightful property--a harvest of rubber. For more than a decade -foreigners have been coming down from the plateau to exploit them. They -are an independent and free tribe and have simple yet correct ideas of -right and wrong. Their chief, a man of great strength of character and -one of the most likeable men I have known, told me that he placed the -skull in the pass to warn away the whites who came to rob honest -Indians. - -The Santa Ana Valley between the Canyon of Torontoy and the heavy forest -belt below Rosalina is typical of many of the eastern valleys of Peru, -both in its physical setting and in its economic and labor systems. -Westward are the outliers of the Vilcapampa range; on the east are the -smaller ranges that front the tropical lowlands. Steep valleys descend -from the higher country to join the main valley and at the mouth of -every tributary is an alluvial fan. If the alluvium is coarse and -steeply inclined there is only pasture on it or a growth of scrub. If -fine and broad it is cleared and tilled. The sugar plantations begin at -Huadquiña and end at Rosalina. Those of Santa Ana and Echarati are the -most productive. It takes eighteen months for the cane to mature in the -cooler weather at Huadquiña (8,000 feet). Less than a year is required -at Santa Ana (3,400 feet). Patches of alluvium or playas, as they are -locally called, continue as far as Santo Anato, but they are cultivated -only as far as Rosalina. The last large plantation is Pabellon; the -largest of all is Echarati. All are irrigated. In the wet months, -December to March inclusive, there is little or no irrigation. In the -four months of the dry season, June to September inclusive, there is -frequent irrigation. Since the cane matures in about ten months the -harvest seasons fall irregularly with respect to the seasons of rain. -Therefore the land is cleared and planted at irregular intervals and -labor distributed somewhat through the year. There is however a -concentration of labor toward the end of the dry season when most of the -cane is cut for grinding. - -The combined freight rate and government tax on coca, sugar, and brandy -take a large part of all that the planter can get for his crop. It is -120 miles (190 km.) from Santa Ana to Cuzco and it takes five days to -make the journey. The freight rate on coca and sugar for mule carriage, -the only kind to be had, is two cents per pound. The national tax is one -cent per pound (0.45 kg.). The coca sells for twenty cents a pound. The -cost of production is unknown, but the paid labor takes probably -one-half this amount. The planter’s time, capital, and profit must come -out of the rest. On brandy there is a national tax of seven cents per -liter (0.26 gallon) and a municipal tax of two and a half cents. It -costs five cents a liter for transport to Cuzco. The total in taxes and -transport is fourteen and a half cents a liter. It sells for twenty -cents a liter. Since brandy (aguardiente), cacao (for chocolate), and -coca leaves (for cocaine) are the only precious substances which the -valleys produce it takes but a moment’s inspection to see how onerous -these taxes would be to the planter if labor did not, as usual, pay the -penalty. - -Much of the labor on the plantations is free of cost to the owner and is -done by the so-called _faena_ or free Indians. These are Quechuas who -have built their cabins on the hill lands of the planters, or on the -floors of the smaller valleys. The disposition of their fields in -relation to the valley plantations is full of geographic interest. Each -plantation runs at right angles to the course of the valley. Hacienda -Sahuayaco is ten miles (16 km.) in extent down valley and forty miles -(64 km.) from end to end across the valley, and it is one of the smaller -plantations! It follows that about ten square miles lie on the valley -floor and half of this can ultimately be planted. The remaining three -hundred and ninety square miles include some mountain country with -possible stores of mineral wealth, and a great deal of “fells†-country--grassy slopes, graded though steep, excellent for pasture, with -here and there patches of arable land. But the hill country can be -cultivated only by the small farmer who supplements his supply of food -from cultivated plants like potatoes, corn, and vegetables, by keeping -cattle, mules, pigs, and poultry, and by raising coca and fruit. - -The Indian does not own any of the land he tills. He has the right -merely to live on it and to cultivate it. In return he must work a -certain number of days each year on the owner’s plantation. In many -cases a small money payment is also made to the planter. The planter -prefers labor to money, for hands are scarce throughout the whole -eastern valley region. No Indian need work on the planter’s land without -receiving pay directly therefor. Each also gets a small weekly allotment -of aguardiente while in the planter’s employ. - -The scene every Saturday night outside the office of the _contador_ -(treasurer) of a plantation is a novel one. Several hundred Indians -gather in the dark patio in front of the office. Within the circle of -the feeble candlelight that reaches only the margin of the crowd one may -see a pack of heavy, perspiring faces. Many are pock-marked from -smallpox; here and there an eye is missing; only a few are jovial. A -name is shouted through the open door and an Indian responds. He pulls -off his cap and stands stupid and blinking, while the contador asks: - -“Faena†(free)? - -“Si, Señor,†he answers. - -“Un sol†(one “sol†or fifty cents gold). The assistant hands over the -money and the man gives way to the next one on the list. If he is a -laborer in regular and constant employ he receives five soles (two fifty -gold) per week. There are interruptions now and then. A ragged, -half-drunken man has been leaning against the door post, suspiciously -impatient to receive his money. Finally his name is called. - -“Faena?†asks the contador. - -“No, Señor, cinco (five) soles.†- -At that the field _superintendente_ glances at his time card and speaks -up in protest. - -“You were the man that failed to show up on Friday and Saturday. You -were drunk. You should receive nothing.†- -“No, mi patrón,†the man contends, “I had to visit a sick cousin in the -next valley. Oh, he was very sick, Señor,†and he coughs harshly as if -he too were on the verge of prostration. The sick cousin, a faena -Indian, has been at work in another cane field on the same plantation -for two days and now calls out that he is present and has never had a -sick day in his life. Those outside laugh uproariously. The contador -throws down two soles and the drunkard is pushed back into the sweating -crowd, jostled right and left, and jeered by all his neighbors as he -slinks away grumbling. - -Another Indian seems strangely shy. He scarcely raises his voice above a -whisper. He too is a faena Indian. The contador finds fault. - -“Why didn’t you come last month when I sent for you?†- -The Indian fumbles his cap, shuffles his feet, and changes his coca cud -from one bulging cheek to the other before he can answer. Then huskily: - -“I started, Señor, but my woman overtook me an hour afterward and said -that one of the ewes had dropped a lamb and needed care.†- -“But your woman could have tended it!†- -“No, Señor, she is sick.†- -“How, then, could she have overtaken you?†he is asked. - -“She ran only a little way and then shouted to me.†- -“And what about the rest of the month?†persists the contador. - -“The other lambs came, Señor, and I should have lost them all if I had -left.†- -The contador seems at the end of his complaint. The Indian promises to -work overtime. His difficulties seem at an end, but the superintendent -looks at his old record. - -“He always makes the same excuse. Last year he was three weeks late.†- -So the poor shepherd is fined a sol and admonished that his lands will -be given to some one else if he does not respond more promptly to his -patron’s call for work. He leaves behind him a promise and the rank -mixed smell of coca and much unwashed woolen clothing. - -It is not alone at the work that they grumble. There is malaria in the -lower valleys. Some of them return to their lofty mountain homes -prostrated with the unaccustomed heat and alternately shaking with -chills and burning with fever. Without aid they may die or become so -weakened that tuberculosis carries them off. Only their rugged strength -enables the greater number to return in good health. - -A plantation may be as large as a principality and draw its laborers -from places fifty miles away. Some of the more distant Indians need not -come to work in the canefields. Part of their flock is taken in place of -work. Or they raise horses and mules and bring in a certain number each -year to turn over to the patron. Hacienda Huadquiña (Fig. 46) takes in -all the land from the snow-covered summits of the Cordillera Vilcapampa -to the canefields of the Urubamba. Within the broad domain are half the -climates and occupations characteristic of Peru. It is difficult to see -how a thousand Indians can be held to even a mixed allegiance. It seems -impossible that word can be got to them. However the native “telegraph†-is even more perfect than that among the forest Indians. From one to the -other runs the news that they are needed in the canefields. On the trail -to and from a mountain village, in their ramblings from one high pasture -to another, within the dark walls of their stone and mud huts when they -gather for a feast or to exchange drinks of brandy and _chicha_--the -word is passed that has come up from the valleys. - -For every hundred faena Indians there are five or six regular laborers -on the plantations, so with the short term passed by the faena Indians -their number is generally half that of the total laborers at work at any -one time. They live in huts provided for them by the planter, and in the -houses of their friends among the regular laborers. Here there are -almost nightly carousals. The regular laborer comes from the city or the -valley town. The faena laborer is a small hill farmer or shepherd. They -have much to exchange in the way of clothing, food, and news. I have -frequently had their conversations interpreted for me. They ask about -the flocks and the children, who passed along the trails, what accidents -befell the people. - -“Last year,†droned one to another over their chicha, “last year we lost -three lambs in a hailstorm up in the high fields near the snow. It was -very cold. My foot cracked open and, though I have bound it with wet -coca leaves every night, it will not cure,†and he displays his heel, -the skin of which is like horn for hardness and covered with a crust of -dirt whose layers are a record of the weather and of the pools he has -waded for years. - -Their wanderings are the main basis of conversation. They know the -mountains better than the condors do. We hired a small boy of twelve at -Puquiura. He was to build our fires, carry water, and help drive the -mules. He crossed the Cordillera Vilcapampa on foot with us. He -scrambled down into the Apurimac canyon and up the ten thousand feet of -ascent on the other side, twisted the tails of the mules, and shouted -more vigorously then the arrieros. He was engaged to go with us to -Pasaje, where his father would return with him in a month. But he -climbed to Huascatay with us and said he wanted to see Abancay. When an -Indian whom we pressed into service dropped the instruments on the trail -and fled into the brush the boy packed them like a man. The soldier -carried a tripod on his back. The boy, not to be outdone, insisted on -carrying the plane table, and to his delight we called him a soldier -too. He went with us to Huancarama. When I paid him he smiled at the -large silver soles that I put into his hand; and when I doubled the -amount for his willingness to work his joy was unbounded. Forthwith he -set out, this time on muleback, on the return journey. The last I saw of -him he was holding his precious soles in a handkerchief and kicking his -beast with his bare heels, as light-hearted as a cavalier. Often I find -myself wondering whether he returned safely with his money. I should -very much like to see him again, for with him I associate cheerfulness -in difficult places and many a pleasant camp-fire. - - - - -CHAPTER VII - -THE GEOGRAPHIC BASIS OF REVOLUTIONS AND OF HUMAN CHARACTER IN THE -PERUVIAN ANDES - - -Human character as a spontaneous development has always been a great -factor in shaping historical events, but it is a striking fact that in -the world of our day its influence is exerted chiefly in the lowest and -highest types of humanity. The savage with his fetishes, his taboos, and -his inherent childlikeness and suspicion needs only whim or a slight -religious pretext to change his conduct. Likewise the really educated -and the thoughtful act from motives often wholly unrelated to economic -conditions or results. But the masses are deeply influenced by whatever -affects their material welfare. A purely idealistic impulse may -influence a people, but in time its effects are always displayed against -an economic background. - -There is a way whereby we may test this theory. In most places in the -world we have history in the making, and through field studies we can -get an intimate view of it. It is peculiarly the province of geography -to study the present distribution and character of men in relation to -their surroundings and these are the facts of mankind that must forever -be the chief data of economic history. It is not vain repetition to say -that this means, first of all, the study of the character of men in the -fullest sense. It means, in the second place, that a large part of the -character must be really understood. Whenever this is done there is -found a geographic basis of human character that is capable of the -clearest demonstration. It is in the geographic environment that the -material motives of humanity have struck their deepest roots. - -These conclusions might be illustrated from a hundred places in the -field of study covered in this book. Almost every chapter of Part I -contains facts of this character. I wish, however, to discuss the -subject specifically and for that purpose now turn to the conditions of -life in the remoter mountain valleys and to one or two aspects of the -revolutions that occur now and then in Peru. The last one terminated -only a few months before our arrival and it was a comparatively easy -matter to study both causes and effects. - -A caution is necessary however. It is a pity that we use the term -“revolution†to designate these little disturbances. They affect -sometimes a few, again a few hundred men. Rarely do they involve the -whole country. A good many of them are on a scale much smaller than our -big strikes. Most of them involve a loss of life smaller than that which -accompanies a city riot. They are in a sense strikes against the -government, marked by local disorders and a little violence. - -Early in 1911 the Prefect of the Department of Abancay had crowned his -long career by suppressing a revolution. He had been Subprefect at -Andahuaylas, and when the rebels got control of the city of Abancay and -destroyed some of the bridges on the principal trails, he promptly -organized a military expedition, constructed rafts, floated his small -force of men across the streams, and besieged the city. The rebel force -was driven at last to take shelter in the city jail opposite the -Prefectura. There, after the loss of half their number, they finally -surrendered. Seventy-five of them were sent to the government -penitentiary at Arequipa. Among the killed were sons from nearly half -the best families of Abancay. All of the rebels were young men. - -It would be difficult to give an adequate idea of the hatred felt by the -townspeople toward the government. Every precaution was taken to prevent -a renewal of the outbreak. Our coming was telegraphed ahead by -government agents who looked with suspicion upon a party of men, well -armed and provisioned, coming up from the Pasaje crossing of the -Apurimac, three days’ journey north. The deep canyon affords shelter not -only to game, but also to fugitives, rebels, and bandits. The government -generally abandons pursuit on the upper edge of the canyon, for only a -prolonged guerilla warfare could completely subdue an armed force -scattered along its rugged walls and narrow floor. The owner of the -hacienda at Pasaje is required to keep a record of all passengers rafted -across the Apurimac, but he explains significantly that some who pass -are too hurried to write their names in his book. Once he reaches the -eastern wall of the canyon a fugitive may command a view of the entire -western wall and note the approach of pursuers. Thence eastward he has -the whole Cordillera Vilcapampa in which to hide. Pursuit is out of the -question. - -When we arrived, the venerable Prefect, a model of old-fashioned -courtesy, greeted us with the utmost cordiality. He told us of our -movements since leaving Pasaje, and laughingly explained that since we -had sent him no friendly message and had come from a rebel retreat, he -had taken it for granted that we intended to storm the town. I assured -him that we were ready to join his troops, if necessary, whereupon, with -a delightful frankness, he explained his method of keeping the situation -in hand. Several troops of cavalry and two battalions of infantry were -quartered at the government barracks. Every evening the old gentleman, a -Colonel in the Peruvian army, mounted a powerful gray horse and rode, -quite unattended, through the principal streets of the town. Several -times I walked on foot behind him, again I preceded him, stopping in -shops on the way to make trivial purchases, to find out what the people -had to say about him and the government as he rode by. One old gentleman -interested me particularly. He had only the day before called at the -Prefectura to pay his respects. Although his manner was correct there -was lacking to a noticeable degree the profusion of sentiment that is -apt to be exhibited on such an occasion. He now sat on a bench in a -shop. Both his own son and the shopkeeper’s son had been slain in the -revolution. It was natural that they should be bitter. But the precise -nature of their complaint was what interested me most. One said that he -did not object to having his son lose his life for his country. But that -his country’s officials should hire Indians to shoot his son seemed to -him sheer murder. Later, at Lambrama, I talked with a rebel fugitive, -and that was also his complaint. The young men drafted into the army are -Indians, or mixed, never whites. White men, and men with a small -amount of Indian blood, officer the army. When a revolutionary party -organizes it is of course made up wholly of men of white and mixed -blood, never Indians. The Indians have no more grievance against one -white party than another. Both exploit him to the limit of law and -beyond the limit of decency. He fights if he must, but never by choice. - -[Illustration: FIG. 56--The type of forest in the moister tracts of the -valley floor at Sahuayaco. In the center of the photograph is a tree -known as the “sandy matico†used in making canoes for river navigation.] - -[Illustration: FIG. 57--Arboreal cacti in the mixed forest of the dry -valley floor below Sahuayaco.] - -[Illustration: FIG. 58--Crossing the Apurimac at Pasaje. These are -mountain horses, small and wiry, with a protective coat of long hair. -They are accustomed to graze in the open without shelter during the -entire winter.] - -[Illustration: FIG. 59--Crossing the Apurimac at Pasaje. The mules are -blindfolded and pushed off the steep bank into the water and rafted -across.] - -Thus Indian troops killed the white rebels of Abancay. - -“Tell me, Señor,†said the fugitive, “if you think that just. Tell me -how many Indians you think a white man worth. Would a hundred dead -Indians matter? But how replace a white man where there are so few? The -government _assassinated_ my compatriots!†- -“But,†I replied, “why did you fight the government? All of you were -prosperous. Your fathers may have had a grievance against the -government, but of what had you young men to complain?†- -His reply was far from convincing. He was at first serious, but his long -abstract statements about taxes and government wastefulness trailed off -into vagueness, and he ended in a laughing mood, talking about -adventure, the restless spirit of young men, and the rich booty of -confiscated lands and property had the rebels won. He admitted that it -was a reckless game, but when I called him a mere soldier of fortune he -grew serious once more and reverted to the iniquitous taxation system of -Peru. Further inquiry made it quite clear that the ill-fated revolution -of Abancay was largely the work of idle young men looking for adventure. -It seemed a pity that their splendid physical energy could not have been -turned into useful channels. The land sorely needs engineers, -progressive ranchmen and farmers, upright officials, and a spirit of -respect for law and order. Old men talked of the unstable character of -the young men of the time, but almost all of them had themselves been -active participants in more than one revolution of earlier years. - -Every night at dinner the Prefect sent off by government telegraph a -long message to the President of the Republic on the state of the -Department, and received similar messages from the central government -about neighboring departments. These he read to us, and, curiously -enough, to the entire party, made up of army officers and townsmen. I -was surprised to find later that the company included one government -official whose son had been among the imprisoned rebels at Arequipa. We -met the young man a week later at a mountain village, a day after a -general amnesty had been declared. His escape had been made from the -prison a month before. He forcibly substituted the mess-boy’s clothing -for his own, and thus passed out unnoticed. After a few days’ hiding in -the city, he set out alone across the desert of Vitor, thence across the -lofty volcanic country of the Maritime Andes, through some of the most -deserted, inhospitable land in Peru, and at the end of three weeks had -reached Lambrama, near Abancay, the picture of health! - -Later I came to have a better notion of the economic basis of the -revolution, for obviously the planters and the reckless young men must -have had a mutual understanding. Somewhere the rebels had obtained the -sinews of war. The planters did not take an open part in the revolution, -but they financed it. When the rebels were crushed, the planters, at -least outwardly, welcomed the government forces. Inwardly they cursed -them for thwarting their scheme. The reasons have an interesting -geographic basis. Abancay is the center of a sugar region. Great -irrigated estates are spread out along the valley floor and the enormous -alluvial fans built into the main valley at the mouths of the tributary -streams. There is a heavy tax on sugar and on aguardiente (brandy) -manufactured from cane juice. The _hacendados_ had dreamed of lighter -taxes. The rebels offered the means of securing relief. But taxes were -not the real reason for the unrest, for many other sugar producers pay -the tax without serious complaint. Abancay is cut off from the rest of -Peru by great mountains. Toward the west, _via_ Antabamba, Cotahuasi, -and Chuquibamba, two hundred miles of trail separate its plantations -from the Pacific. Twelve days’ hard riding is required to reach Lima -over the old colonial trade route. It is three days to Cuzco at the end -of the three-hundred-mile railway from the port of Mollendo. The trails -to the Atlantic rivers are impossible for trading purposes. Deep sunk in -a subtropical valley, the irrigable alluvial land of Abancay tempts the -production of sugar. - -But nature offers no easy route out of the valley. For centuries the -product has been exported at almost prohibitive cost, as in the eastern -valley of Santa Ana. The coastal valleys enjoy easy access to the sea. -Each has its own port at the valley mouth, where ocean steamers call for -cargo. Many have short railway lines from port to valley head. The -eastern valleys and Abancay have been clamoring for railways, better -trails, and wagon roads. From the public fund they get what is left. The -realization of their hopes has been delayed too long. It would be both -economic and military strategy to give them the desired railway. -Revolutions in Peru always start in one of two ways: either by a _coup_ -at Lima or an unchecked uprising in an interior province. Bolivia has -shown the way out of this difficulty. Two of her four large centers--La -Paz and Oruro--are connected by rail, and the line to Cochabamba lacks -only a few kilometres of construction.[16] To Sucre a line has been long -projected. Formerly a revolution at one of the four towns was -exceedingly difficult to stamp out. Diaz had the same double motive in -encouraging railway building in the remote desert provinces of Northern -Mexico, where nine out of ten Mexican revolutions gather headway. -Argentina has enjoyed a high degree of political unity since her railway -system was extended to Córdoba and Tucumán. The last uprising, that of -1906, took place on her remotest northeastern frontier. - -We had ample opportunity to see the hatred of the rebels. At nightfall -of September 25th we rode into the courtyard of Hacienda Auquibamba. We -had traveled under the worst possible circumstances. Our mules had been -enfeebled by hot valley work at Santa Ana and the lower Urubamba and the -cold mountain climate of the Cordillera Vilcapampa. The climb out of the -Apurimac canyon, even without packs, left them completely exhausted. We -were obliged to abandon one and actually to pull another along. It had -been a hard day in spite of a prolonged noon rest. Everywhere our -letters of introduction had won an outpouring of hospitality among a -people to whom hospitality is one of the strongest of the unwritten laws -of society. Our soldier escort rode ahead of the pack train. - -As the clatter of his mules’ hoofs echoed through the dark buildings the -manager rushed out, struck a light and demanded “Who’s there?†To the -soldier’s cheerful “Buena noche, Señor,†he sneeringly replied “Halto! -Guardia de la República, aqui hay nada para un soldado del gobierno.†-Whereupon the soldier turned back to me and said we should not be able -to stop here, and coming nearer me he whispered “He is a revolutionary.†-I dismounted and approached the haughty manager, who was in a really -terrible mood. Almost before I could begin to ask him for accommodations -he rattled off that there was no pasture for our beasts, no food for us, -and that we had better go on to the next hacienda. “Absolutamente nada!†-he repeated over and over again, and at first I thought him drunk. Since -it was then quite dark, with no moon, but instead heavy black clouds -over the southern half of the sky and a brisk valley wind threatening -rain, I mildly protested that we needed nothing more than shelter. Our -food boxes would supply our wants, and our mules, even without fodder, -could reach Abancay the next day. Still he stormed at the government and -would have none of us. I reminded him that his fields were filled with -sugar cane and that it was the staple forage for beasts during the part -of the year when pasture was scarce. The cane was too valuable, he said. -It was impossible to supply us. I was on the point of pitching camp -beside the trail, for it was impossible to reach the next hacienda with -an exhausted outfit. - -Just then an older man stepped into the circle of light and amiably -inquired the purpose of our journey. When it was explained, he turned to -the other and said it was unthinkable that men should be treated so -inhospitably in a strange land. Though he himself was a guest he urged -that the host should remember the laws of hospitality, whereupon the -latter at last grudgingly asked us to join him at his table and to turn -our beasts over to his servants. It was an hour or more before he would -exhibit any interest in us. When he had learned of our object in -visiting Abancay he became somewhat more friendly, though his hostility -still manifested itself. Nowhere else in South America have I seen -exhibited such boorish conduct. Nevertheless the next morning I noticed -that our mules had been well fed. He said good-by to us as if he were -glad to be rid of any one in any way connected with the hostile -government. Likewise the manager at Hacienda Pasaje held out almost -until the last before he would consent to aid us with fresh beasts. -Finally, after a day of courting I gave him a camp chair. He was so -pleased that he not only gave us beasts, but also a letter of -introduction to one of his caretakers on a farm at the top of the -cuesta. Here on a cold, stormy night we found food and fuel and the -shelter of a friendly roof. - -A by-product of the revolution, as of all revolutions in thinly settled -frontier regions, was the organization of small bands of outlaws who -infested the lonely trails, stole beasts, and left their owners robbed -and helpless far from settlements. We were cautioned to beware of them, -both by Señor Gonzales, the Prefect at Abancay, and by the Subprefect of -Antabamba. Since some of the bandits had been jailed, I could not doubt -the accuracy of the reports, but I did doubt stories of murder and of -raids by large companies of mountain bandits. As a matter of fact we -were robbed by the Governor of Antabamba, but in a way that did not -enable us to find redress in either law or lead. The story is worth -telling because it illustrates two important facts: first, the vile -so-called government that exists in some places in the really remote -sections of South America, and second, the character of the mountain -Indians. - -The urgent letter from the Prefect of Abancay to the Subprefect of -Antabamba quickly brought the latter from his distant home. When we -arrived we found him drinking with the Governor. The Subprefect was most -courteous. The Governor was good-natured, but his face exhibited a rare -combination of cruelty and vice. We were offered quarters in the -municipal building for the day or two that we were obliged to stop in -the town. The delay enabled us to study the valley to which particular -interest attaches because of its situation in the mountain zone between -the lofty pastures of the Alpine country and the irrigated fields of the -valley farmers. - -Antabamba itself lies on a smooth, high-level shoulder of the youthful -Antabamba Valley. The valley floor is narrow and rocky, and affords -little cultivable land. On the valley sides are steep descents and -narrow benches, chiefly structural in origin, over which there is -scattered a growth of scrub, sufficient to screen the deer and the bear, -and, more rarely, vagrant bands of vicuña that stray down from their -accustomed haunts in the lofty Cordillera. Three thousand feet above the -valley floor a broad shoulder begins (Fig. 60) and slopes gently up to -the bases of the true mountains that surmount the broad rolling summit -platform. Here are the great pasture lands of the Andes and their -semi-nomadic shepherds. The highest habitation in the world is located -here at 17,100 feet (5,210 m.), near a secondary pass only a few miles -from the main axis of the western chain, and but 300 feet (91 m.) below -it. - -The people of Antabamba are both shepherds and farmers. The elevation is -12,000 feet (3,658 m.), too high and exposed for anything more than -potatoes. Here is an Indian population pure-blooded, and in other -respects, too, but little altered from its original condition. There is -almost no communication with the outside world. A deep canyon fronts the -town and a lofty mountain range forms the background. - -At nightfall, one after another, the Indians came in from the field and -doffed their caps as they passed our door. Finally came the “Teniente -Gobernador,†or Lieutenant Governor. He had only a slight strain of -white blood. His bearing was that of a sneak, and he confirmed this -impression by his frank disdain for his full-blooded townsmen. “How -ragged and ugly they are! You people must find them very stupid,†etc. -When he found that we had little interest in his remarks, he asked us if -we had ever seen Lima. We replied that we had, whereupon he said, “Do -you see the gilded cross above the church yonder? I brought that on -muleback all the way from Lima! Think of it! These ignorant people have -never seen Lima!†His whole manner as he drew himself up and hit his -breast was intended to make us think that he was vastly superior to his -neighbors. The sequel shows that our first estimate of him was correct. - -We made our arrangements with the Governor and departed. To inspire -confidence, and at the Governor’s urgent request, we had paid in advance -for our four Indians and our fresh beasts--and at double the usual -rates, for it was still winter in the Cordillera. They were to stay with -us until we reached Cotahuasi, in the next Department beyond the -continental divide, where a fresh outfit could be secured. The -Lieutenant Governor accompanied us to keep the party together. They -appeared to need it. Like our Indian peons at Lambrama the week before, -these had been taken from the village jail and represented the scum of -the town. As usual they behaved well the first day. On the second night -we reached the Alpine country where the vegetation is very scanty and -camped at the only spot that offered fuel and water. The elevation was -16,000, and here we had the lowest temperature of the whole journey, +6° -F. (-14.4° C.). Ice covered the brook near camp as soon as the sun went -down and all night long the wind blew down from the lofty Cordillera -above us, bringing flurries of snow and tormenting our unprotected -beasts. It seemed to me doubtful if our Indians would remain. I -discussed with the other members of the party the desirability of -chaining the peons to the tent pole, but this appeared so extreme a -measure that we abandoned the idea after warning the Teniente that he -must not let them escape. - -At daybreak I was alarmed at the unusual stillness about camp. A glance -showed that half our hobbled beasts had drifted back toward Antabamba -and no doubt were now miles away. The four Indian peons had left also, -and their tracks, half buried by the last snowfall, showed that they had -left hours before and that it was useless to try to overtake them. -Furthermore we were making a topographic map across the Cordillera, and, -in view of the likelihood of snow blockading the 17,600-foot (5,360 m.) -pass which we had to cross, the work ought not to be delayed. With all -these disturbing conditions to meet, and suffering acutely from mountain -sickness, I could scarcely be expected to deal gently with our official. -I drew out the sleeping Teniente and set him on his feet. To my inquiry -as to the whereabouts of the Indians that he had promised to guard, he -blinked uncertainly, and after a stupid “Quien sabe?†peered under the -cover of a sheepskin near by as if the peons had been transformed into -insects and had taken refuge under a blade of grass. I ordered him to -get breakfast and after that to take upon his back the instruments that -two men had carried up to that time, and accompany the topographer. Thus -loaded, the Lieutenant Governor of Antabamba set out on foot a little -ahead of the party. Hendriksen, the topographer, directed him to a -17,000-foot peak near camp, one of the highest stations occupied in the -traverse. When the topographer reached the summit the instruments were -there but the Teniente had fled. Hendriksen rapidly followed the tracks -down over the steep snow-covered wall of a deeply recessed cirque, but -after a half-hour’s search could not get sight of the runaway, whereupon -he returned to his station and took his observations, reaching camp in -the early afternoon. - -In the meantime I had intercepted two Indians who had come from -Cotahuasi driving a llama train loaded with corn. They held a long -conversation at the top of the pass above camp and at first edged -suspiciously away. But the rough ground turned them back into the trail -and at last they came timidly along. They pretended not to understand -Spanish and protested vigorously that they had to keep on with their -llamas. I thought from the belligerent attitude of the older, which grew -rapidly more threatening as he saw that I was alone, that I was in for -trouble, but when I drew my revolver he quickly obeyed the order to sit -down to breakfast, which consisted of soup, meat, and army biscuits. I -also gave them coca and cigarettes, the two most desirable gifts one can -make to a plateau Indian, and thereupon I thought I had gained their -friendship, for they at last talked with me in broken Spanish. The older -one now explained that he must at all hazards reach Matará by nightfall, -but he would be glad to leave his son to help us. I agreed, and he set -out forthwith. The _arriero_ (muleteer) had now returned with the lost -mules and with the assistance of the Indian we soon struck camp and -loaded our mules. I cautioned the arriero to keep close watch of the -Indian, for at one time I had caught on his face an expression of hatred -more intense than I had ever seen before. The plateau Indian of South -America is usually so stupid and docile that the unexpectedly venomous -look of the man after our friendly conversation and my good treatment -alarmed me. At the last moment, and when our backs were turned, our -Indian, under the screen of the packs, slipped away from us. The arriero -called out to know where he had gone. It took us but a few moments to -gain the top of a hill that commanded the valley. Fully a half-mile away -and almost indistinguishable against the brown of the valley floor was -our late assistant, running like a deer. No mule could follow over that -broken ground at an elevation of 16,000 feet, and so he escaped. - -Fortunately that afternoon we passed a half-grown boy riding back toward -Antabamba and he promised to hand the Governor a note in Spanish, -penciled on a leaf of my traverse book. I dropped all the polite phrases -that are usually employed and wrote as follows: - - -“Señor Gobernador: - - “Your Indians have escaped, likewise the Lieutenant Governor. They - have taken two beasts. In the name of the Prefect of Abancay, I ask - you immediately to bring a fresh supply of men and animals. We - shall encamp near the first pass, three days west of Antabamba, - until you come.†- -We were now without Indians to carry the instruments, which had -therefore to be strapped to the mules. Without guides we started -westward along the trail. At the next pass the topographer rode to the -summit of a bluff and asked which of the two trails I intended to -follow. Just then a solitary Indian passed and I shouted back that I -would engage the Indian and precede the party, and he could tell from my -course at the fork of the trail how to direct his map and where to gain -camp at nightfall. But the Indian refused to go with us. All my -threatening was useless and I had to force myself to beat him into -submission with my quirt. Several repetitions on the way, when he -stubbornly refused to go further, kept our guide with us until we -reached a camp site. I had offered him a week’s pay for two hours’ work, -and had put coca and cigarettes into his hands. When these failed I had -to resort to force. Now that he was about to leave I gave him double the -amount I had promised him. He could scarcely believe his eyes. He rushed -up to the side of my mule, and reaching around my waist embraced me and -thanked me again and again. The plateau Indian is so often waylaid in -the mountains and impressed for service, then turned loose without pay -or actually robbed, that a _promise_ to pay holds no attraction for him. -I had up to the last moment resembled this class of white. He was -astonished to find that I really meant to pay him well. - -Then he set out upon the return, faithfully delivering my note to the -topographer about the course of the trail and the position of the camp. -He had twelve miles to go to the first mountain hut, so that he could -not have traveled less than that distance to reach shelter. The next -morning a mantle of snow covered everything, yet when I pushed back the -tent flap there stood my scantily clad Indian of the night before, -shivering, with sandaled feet in the snow, saying that he had come back -to work for me! - -This camp was number thirteen out of Abancay, and here our topographer -was laid up for three days. Heretofore the elevation had had no effect -upon him, but the excessively lofty stations of the past few days and -the hard climbing had finally prostrated him. We had decided to carry -him out by the fourth day if he felt no better, but happily he recovered -sufficiently to continue the work. The delay enabled the Governor to -overtake us with a fresh outfit. On the morning of our third day in -camp he overtook us with a small escort of soldiers accompanied by the -fugitive Teniente. He said that he had come to arrest me on the charge -of maltreating an official of Peru. A few packages of cigarettes and a -handful of raisins and biscuits so stirred his gratitude that we parted -the best of friends. Moreover he provided us with four fresh beasts and -four new men, and thus equipped we set out for a rendezvous about ten -miles away. But the faithless Governor turned off the trail and sought -shelter at the huts of a company of mountain shepherds. That night his -men slept on the ground in a bitter wind just outside our camp at 17,200 -feet. They complained that they had no food. The Governor had promised -to join us with llama meat for the peons. We fed them that night and -also the next day. But we had by that time passed the crest of the -western Cordillera and were outside the province of Antabamba. The next -morning not only our four men but also our four beasts were missing. We -were stranded and sick just under the pass. To add to our distress the -surgeon, Dr. Erving, was obliged to leave us for the return home, taking -the best saddle animal and the strongest pack mule. It was impossible to -go on with the map. That morning I rode alone up a side valley until I -reached a shepherd’s hut, where I could find only a broken-down, -shuffling old mule, perfectly useless for our hard work. - -Then there happened a piece of good luck that seems almost providential. -A young man came down the trail with three pack mules loaded with llama -meat. He had come from the Cotahuasi Valley the week before and knew the -trail. I persuaded him to let us hire one of his mules. In this way and -by leaving the instruments and part of our gear in the care of two -Indian youths we managed to get to Cotahuasi for rest and a new outfit. - -The young men who took charge of part of our outfit interested me very -greatly. I had never seen elsewhere so independent and clear-eyed a pair -of mountain Indians. At first they would have nothing to do with us. -They refused us permission to store our goods in their hut. To them we -were railroad engineers. They said that the railway might come and when -it did it would depopulate the country. The railway was a curse. -Natives were obliged to work for the company without pay. Their uncle -had told them of frightful abuses over at Cuzco and had warned them not -to help the railway people in any way. They had moved out here in a -remote part of the mountains so that white men could not exploit them. - -In the end, however, we got them to understand the nature of our work. -Gifts of various sorts won their friendship, and they consented to guard -the boxes we had to leave behind. Two weeks later, on his return, the -topographer found everything unmolested. - -I could not but feel that the spirit of those strong and independent -young men was much better for Peru than the cringing, subservient spirit -of most of the Indians that are serfs of the whites. The policy of the -whites has been to suppress and exploit the natives, to abuse them, and -to break their spirit. They say that it keeps down revolution; it keeps -the Indian in his place. But certainly in other respects it is bad for -the Indian and it is worse for the whites. Their brutality toward the -natives is incredible. It is not so much the white himself as the -vicious half-breed who is often allied with him as his agent. - -I shall never forget the terror of two young girls driving a donkey -before them when they came suddenly face to face with our party, and we -at the same time hastily scrambled off our beasts to get a photograph of -a magnificent view disclosed at the bend of the steep trail. They -thought we had dismounted to attack them, and fled screaming in abject -fear up the mountain side, abandoning the donkey and the pack of -potatoes which must have represented a large part of the season’s -product. It is a kind of highway robbery condoned because it is only -robbing an Indian. He is considered to be lawful prey. His complaint -goes unnoticed. In the past a revolution has offered him sporadic -chances to wreak vengeance. More often it adds to his troubles by -scattering through the mountain valleys the desperate refugees or -lawless bands of marauders who kill the flocks of the mountain shepherds -and despoil their women. - -There are still considerable numbers of Indians who shun the white man -and live in the most remote corners of the mountains. I have now and -again come upon the most isolated huts, invisible from the valley -trails. They were thatched with grass; the walls were of stone; the -rafters though light must have required prodigious toil, for all timber -stops at 12,000 feet on the mountain borders. The shy fugitive who -perches his hut near the lip of a hanging valley far above the trail may -look down himself unseen as an eagle from its nest. When the owner -leaves on a journey, or to take his flock to new pastures, he buries his -pottery or hides it in almost inaccessible caves. He locks the door or -bars it, thankful if the spoiler spares rafters and thatch. - -At length we reached Cotahuasi, a town sprawled out on a terrace just -above the floor of a deep canyon (Fig. 29). Its flower gardens and -pastures are watered by a multitude of branching canals lined with low -willows. Its bright fields stretch up the lower slopes and alluvial fans -of the canyon to the limits of irrigation where the desert begins. The -fame of this charming oasis is widespread. The people of Antabamba and -Lambrama and even the officials of Abancay spoke of Cotahuasi as -practically the end of our journey. Fruits ripen and flowers blossom -every month of the year. Where we first reached the canyon floor near -Huaynacotas, elevation 11,500 feet (3,500 m.), there seemed to be acres -of rose bushes. Only the day before at an elevation of 16,800 feet -(5,120 m.) we had broken thick ice out of a mountain spring in order to -get water; now we were wading a shallow river, and grateful for the -shade along its banks. Thus we came to the town prepared to find the -people far above their plateau neighbors in character. Yet, in spite of -friendly priests and officials and courteous shopkeepers, there was a -spirit strangely out of harmony with the pleasant landscape. - -Inquiries showed that even here, where it seemed that only sylvan peace -should reign, there had recently been let loose the spirit of barbarism. -We shall turn to some of its manifestations and look at the reasons -therefor. - -In the revolution of 1911 a mob of drunken, riotous citizens gathered to -storm the Cotahuasi barracks and the jail. A full-blooded Indian -soldier, on duty at the entrance, ordered the rioters to stop and when -they paid no heed he shot the leader and scattered the crowd. The -captain thereupon ordered the soldier to Arequipa because his life was -no longer safe outside the barracks. A few months later he was assigned -to Professor Bingham’s Coropuna expedition. Professor Bingham reached -the Cotahuasi Valley as I was about to leave it for the coast, and the -soldier was turned over to me so that he might leave Cotahuasi at the -earliest possible moment, for his enemies were plotting to kill him. - -He did not sleep at all the last night of his stay and had us called at -three in the morning. He told his friends that he was going to leave -with us, but that they were to announce his leaving a day later. In -addition, the Subprefect was to accompany us until daybreak so that no -harm might befall me while under the protection of a soldier who -expected to be shot from ambush. - -At four o’clock our whispered arrangements were made, we opened the -gates noiselessly, and our small cavalcade hurried through the -pitch-black streets of the town. The soldier rode ahead, his rifle -across his saddle, and directly behind him rode the Subprefect and -myself. The pack mules were in the rear. We had almost reached the end -of the street when a door opened suddenly and a shower of sparks flew -out ahead of us. Instantly the soldier struck spurs into his mule and -turned into a side street. The Subprefect drew his horse back savagely -and when the next shower of sparks flew out pushed me against the wall -and whispered: “Por Dios, quien es?†Then suddenly he shouted: “Sopla no -mas, sopla no mas†(stop blowing). - -Thereupon a shabby penitent man came to the door holding in his hand a -large tailor’s flatiron. The base of it was filled with glowing charcoal -and he was about to start his day’s work. The sparks were made in the -process of blowing through the iron to start the smoldering coals. We -greeted him with more than ordinary friendliness and passed on. - -At daybreak we had reached the steep western wall of the canyon where -the real ascent begins, and here the Subprefect turned back with many -_felicidades_ for the journey and threats for the soldier if he did not -look carefully after the pack train. From every angle of the zigzag -trail that climbs the “cuesta†the soldier scanned the valley road and -the trail below him. He was anxious lest news of his escape reach his -enemies who had vowed to take his life. Half the day he rode turned in -his saddle so as to see every traveler long before he was within harm’s -reach. By nightfall we safely reached Salamanca, fifty miles away (Fig. -62). - -The alertness of the soldier was unusual and I quite enjoyed his close -attention to the beasts and his total abstinence, for an alert and sober -soldier on detail is a rare phenomenon in the interior of Peru. But all -Salamanca was drunk when we arrived--Governor, alcaldes, citizens. Even -the peons drank up in brandy the money that we gave them for forage and -let the beasts starve. The only sober person I saw was the white -telegraph operator from Lima. He said that he had to stay sober, for the -telegraph office--the outward sign of government--was the special object -of attack of every drink-crazed gang of rioters. They had tried to break -in a few nights before and he had fired his revolver point-blank through -the door. The town offered no shelter but the dark filthy hut of the -Gobernador and the tiny telegraph office. So I made up my bed beside -that of the operator. We shared our meals and chatted until a late hour, -he recounting the glories of Lima, to which he hoped to return at the -earliest possible moment, and cursing the squalid town of Salamanca. His -operator’s keys were old, the batteries feeble, and he was in continual -anxiety lest a message could not be received. In the night he sprang out -of bed shouting frantically: - -“Estan llamando†(they are calling), only to stumble over my bed and -awaken himself and offer apologies for walking in his sleep. - -Meanwhile my soldier, having regained his courage, began drinking. It -was with great difficulty that I got started, after a day’s delay, on -the trail to Chuquibamba. There his thirst quite overcame him. To -separate him from temptation it became necessary to lock him up in the -village jail. This I did repeatedly on the way to Mollendo, except -beyond Quilca, where we slept in the hot marshy valley out of reach of -drink, and where the mosquitoes kept us so busy that either eating or -drinking was almost out of the question. - -The drunken rioters of Cotahuasi and their debauched brothers at -Salamanca are chiefly natives of pure or nearly pure Indian blood. They -are a part of the great plateau population of the Peruvian Andes. Have -they degenerated to their present low state, or do they display merely -the normal condition of the plateau people? Why are they so troublesome -an element? To this as to so many questions that arise concerning the -highland population we find our answer not chiefly in government, or -religion, or inherited character, but in geography. I doubt very much if -a greater relative difference would be seen if two groups of whites were -set down, the one in the cold terrace lands of Salamanca, the other in -the warm vineyards of Aplao, in the Majes Valley. The common people of -these two towns were originally of the same race, but the lower valley -now has a white element including even most of those having the rank of -peons. Greater differences in character could scarcely be found between -the Aztecs and the Iroquois. In the warm valley there is of coarse -drunkenness, but it is far from general; there is stupidity, but the -people are as a whole alert; and finally, the climate and soil produce -grapes from which famous wines are made, they produce sugar cane, -cotton, and alfalfa, so that the whites have come in, diluted the Indian -blood, and raised the standard of life and behavior. Undoubtedly their -influence would tend to have the same general effect if they mixed in -equal numbers with the plateau groups. There is, however, a good reason -for their not doing so. - -[Illustration: FIG. 62--Salamanca, on the floor of the deep Arma Valley -(a tributary of one of the major coast valleys, the Ocoña), which is -really a canyon above this point and which, in spite of its steepness, -is thoroughly terraced and intensively cultivated up to the frost line.] - -[Illustration: FIG. 60--View across the Antabamba canyon just above -Huadquirca.] - -[Illustration: FIG. 61--Huancarama, west of Abancay, on the famous Lima -to Buenos Aires road. Note the smooth slopes in the foreground. See -Chapter XI.] - -The lofty towns of the plateau have a really wretched climate. White men -cannot live comfortably at Antabamba and Salamanca. Further, they are so -isolated that the modest comforts and the smallest luxuries of -civilization are very expensive. To pay for them requires a profitable -industry managed on a large scale and there is no such industry in the -higher valleys. The white who goes there must be satisfied to live like -an Indian. The result is easy to forecast. Outside of government -officers, only the dissolute or unsuccessful whites live in the worst -towns, like Salamanca and Antabamba. A larger valley with a slightly -milder climate and more accessible situation, like Chuquibamba, will -draw a still better grade of white citizen and in the largest of -all--Cuzco and the Titicaca basin--we find normal whites in larger -numbers, though they nowhere live in such high ratios to the Indian as -on the coast and in the lower valleys near the coast. With few -exceptions the white population of Peru is distributed in response to -favorable combinations of climate, soil, accessibility, and general -opportunities to secure a living without extreme sacrifice. - -These facts are stated in a simple way, for I wish to emphasize the -statement that the Indian population responds to quite other stimuli. -Most of the luxuries and comforts of the whites mean nothing to the -Indian. The machine-made woolens of the importers will probably never -displace his homespun llama-wool clothing. His implements are few in -number and simple in form. His tastes in food are satisfied by the few -products of his fields and his mountain flocks. Thus he has lived for -centuries and is quite content to live today. Only coca and brandy tempt -him to engage in commerce, to toil now and then in the hot valleys, and -to strive for more than the bare necessities of life. Therefore it -matters very little to him if his home town is isolated, or the -resources support but a small group of people. He is so accustomed to a -solitary existence in his ramblings with his flocks that a village of -fifty houses offers social enjoyments of a high order. Where a white -perishes for lack of society the Indian finds himself contented. -Finally, he is not subject to the white man’s exploitation when he lives -in remote places. The pastures are extensive and free. The high valley -lands are apportioned by the alcalde according to ancient custom. His -life is unrestricted by anything but the common law and he need have no -care for the morrow, for the seasons here are almost as fixed as the -stars. - -Thus we have a sort of segregation of whites in the lower places where a -modern type of life is maintained and of Indians in the higher places -where they enjoy advantages that do not appeal to the whites. Above -8,000 feet the density of the white population bears a close inverse -proportion to the altitude, excepting in the case of the largest valleys -whose size brings together such numbers as to tempt the commercial and -exploiting whites to live in them. Furthermore, we should find that high -altitude, limited size, and greater isolation are everywhere closely -related to increasing immorality or decreasing character among the -whites. So to the low Indian population there is thus added the lowest -of the white population. Moreover, because it yields the largest -returns, the chief business of these whites is the sale of coca and -brandy and the downright active debauchery of the Indian. This is all -the easier for them because the isolated Indian, like the average -isolated white, has only a low and provincial standard of morality and -gets no help from such stimulation as numbers usually excite. - -For example, the Anta basin at harvest time is one of the fairest sights -in Peru. Sturdy laborers are working diligently. Their faces are bright -and happy, their skin clear, their manner eager and animated. They sing -at their work or gather about their mild _chicha_ and drink to the -patron saints of the harvest. The huts are filled with robust children; -all the yards are turned into threshing floors; and from the stubbly -hillslopes the shepherd blows shrill notes upon his barley reeds and -bamboo flute. There is drinking but there is little disorder and there -is always a sober remnant that exercises a restraining influence upon -the group. - -In the most remote places of all one may find mountain groups of a high -order of morality unaffected by the white man or actually shunning him. -Clear-eyed, thick-limbed, independent, a fine, sturdy type of man this -highland shepherd may be. But in the town he succumbs to the temptation -of drink. Some writers have tried to make him out a superior to the -plains and low valley type. He is not that. The well-regulated groups of -the lower elevations are far superior intellectually and morally in -spite of the fact that the poorly regulated groups may fall below the -highland dweller in morality. The coca-chewing highlander is a clod. -Surely, as a whole, the mixed breed of the coastal valleys is a far -worthier type, save in a few cases where a Chinese or negroid element or -both have led to local inferiority. And surely, also, that is the worst -combination which results in adding the viciousness of the inferior or -debased white to the stupidity of the highland Indian. It is here that -the effects of geography are most apparent. If the white is tempted in -large numbers because of exceptional position or resources, as at La -Paz, the rule of altitude may have an exception. And other exceptions -there are not due to physical causes, for character is practically never -a question of geography alone. There is the spiritual factor that may -illumine a strong character and through his agency turn a weak community -into a powerful one, or hold a weakened group steadfast against the -forces of disintegration. Exceptions arise from this and other causes -and yet with them all in mind the geographic factor seems predominant in -the types illustrated herewith.[17] - - - - -CHAPTER VIII - -THE COASTAL DESERT - - -To the wayfarer from the bleak mountains the warm green valleys of the -coastal desert of Peru seem like the climax of scenic beauty. The -streams are intrenched from 2,000 to 4,000 feet, and the valley walls in -some places drop 500 feet by sheer descents from one level to another. -The cultivated fields on the valley floors look like sunken gardens and -now and then one may catch the distant glint of sunlight on water. The -broad white path that winds through vineyards and cotton-fields, follows -the foot of a cliff, or fills the whole breadth of a gorge is the -waste-strewn, half-dry channel of the river. In some places almost the -whole floor is cultivated from one valley wall to the other. In other -places the fields are restricted to narrow bands between the river and -the impending cliffs of a narrow canyon. Where tributaries enter from -the desert there may be huge banks of mud or broad triangular fans -covered with raw, infertile earth. The picture is generally touched with -color--a yellow, haze-covered horizon on the bare desert above, brown -lava flows suspended on the brink of the valley, gray-brown cliffs, and -greens ranging from the dull shade of algarrobo, olive and fig trees, to -the bright shade of freshly irrigated alfalfa pastures. - -After several months’ work on the cold highlands, where we rode almost -daily into hailstorms or wearisome gales, we came at length to the -border of the valley country. It will always seem to me that the weather -and the sky conspired that afternoon to reward us for the months of toil -that lay behind. And certainly there could be no happier place to -receive the reward than on the brink of the lava plateau above -Chuquibamba. There was promise of an extraordinary view in the growing -beauty of the sky, and we hurried our tired beasts forward so that the -valley below might also be included in the picture. The head of the -Majes Valley is a vast hollow bordered by cliffs hundreds of feet high, -and we reached the rim of it only a few minutes before sunset. - -[Illustration: FIG. 63--The deep fertile Majes Valley below Cantas. -Compare with Fig. 6 showing the Chili Valley at Arequipa.] - -[Illustration: FIG. 64--The Majes Valley, desert coast, western Peru. -The lighter patches on the valley floor are the gravel beds of the river -at high water. Much of the alluvial land is still uncleared.] - -I remember that we halted beside a great wooden cross and that our -guide, dismounting, walked up to the foot of it and kissed and embraced -it after the custom of the mountain folk when they reach the head of a -steep “cuesta.†Also that the trail seemed to drop off like a stairway, -which indeed it was.[18] Everything else about me was completely -overshadowed by snowy mountains, colored sky, and golden-yellow desert. -One could almost forget the dark clouds that gather around the great -mass of Coropuna and the bitter winds that creep down from its glaciers -at night--it seemed so friendly and noble. Behind it lay bulky masses of -rose-tinted clouds. We had admired their gay colors only a few minutes, -when the sun dropped behind the crest of the Coast Range and the last of -the sunlight played upon the sky. It fell with such marvelously swift -changes of color upon the outermost zone of clouds as these were shifted -with the wind that the eye had scarcely time to comprehend a tint before -it was gone and one more beautiful still had taken its place. The -reflected sunlight lay warm and soft upon the white peaks of Coropuna, -and a little later the Alpine glow came out delicately clear. - -When we turned from this brilliant scene to the deep valley, we found -that it had already become so dark that its greens had turned to black, -and the valley walls, now in deep shadow, had lost half their splendor. -The color had not left the sky before the lights of Chuquibamba began to -show, and candles twinkled from the doors of a group of huts close under -the cliff. We were not long in starting the descent. Here at last were -friendly habitations and happy people. I had worked for six weeks -between 12,000 and 17,000 feet, constantly ill from mountain sickness, -and it was with no regret that I at last left the plateau and got down -to comfortable altitudes. It seemed good news when the guide told me -that there were mosquitoes in the marshes of Camaná. Any low, hot land -would have seemed like a health resort. I had been in the high country -so long that, like the Bolivian mining engineer, I wanted to get down -not only to sea level, but below it! - -[Illustration: FIG. 65--Regional diagram to show the physical relations -in the coastal desert of Peru. For location, see Fig. 20.] - -If the reader will examine Figs. 65 and 66, and the photographs that -accompany them, he may gain an idea of the more important features of -the coastal region. We have already described, in Chapters V and VII, -the character of the plateau region and its people. Therefore, we need -say little in this place of the part of the Maritime Cordillera that is -included in the figure. Its unpopulated rim (see p. 54), the -semi-nomadic herdsmen and shepherds from Chuquibamba that scour its -pastures in the moist vales about Coropuna, and the gnarled and stunted -trees at 13,000 feet (3,960 m.) which partly supply Chuquibamba with -firewood, are its most important features. A few groups of huts just -under the snowline are inhabited for only a part of the year. The -delightful valleys are too near and tempting. Even a plateau Indian -responds to the call of a dry valley, however he may shun the moist, -warm valleys on the eastern border of the Cordillera. - -[Illustration: FIG. 66--Irrigated and irrigable land of the coastal belt -of Peru. The map exhibits in a striking manner how small a part of the -whole Pacific slope is available for cultivation. Pasture grows over all -but the steepest and the highest portions of the Cordillera to the right -of (above) the dotted line. Another belt of pasture too narrow to show -on the map, grows in the fog belt on the seaward slopes of the Coast -Range. Scale, 170 miles to the inch.] - -The greater part of the coastal region is occupied by the desert. Its -outer border is the low, dry, gentle, eastward-facing slope of the Coast -Range. Its inner border is the foot of the steep descent that marks the -edge of the lava plateau. This descent is a fairly well-marked line, -here and there broken by a venturesome lava flow that extends far out -from the main plateau. Within these definite borders the desert extends -continuously northwestward for hundreds of miles along the coast of Peru -from far beyond the Chilean frontier almost to the border of Ecuador. It -is broken up by deep transverse valleys and canyons into so-called -“pampas,†each of which has a separate name; thus west of Arequipa -between the Vitor and Majes valleys are the “Pampa de Vitor†and the -“Pampa de Sihuas,†and south of the Vitor is the “Pampa de Islay.†- -The pampa surfaces are inclined in general toward the sea. They were -built up to their present level chiefly by mountain streams before the -present deep valleys were cut, that is to say, when the land was more -than a half-mile lower. Some of their material is wind-blown and on the -walls of the valleys are alternating belts of wind-blown and water-laid -strata from one hundred to four hundred feet thick as if in past ages -long dry and long wet periods had succeeded each other. The wind has -blown sand and dust from the desert down into the valleys, but its chief -work has been to drive the lighter desert waste up partly into the -mountains and along their margins, partly so high as to carry it into -the realm of the lofty terrestrial winds, whence it falls upon surfaces -far distant from the fields of origin. There are left behind the heavier -sand which the wind rolls along on the surfaces and builds into -crescentic dunes called médanos, and the pebbles that it can sandpaper -but cannot remove bodily. Thus there are belts of dunes, belts of -irregular sand drifts, and belts of true desert “pavement†(a residual -mantle of faceted pebbles and irregular stones). - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM, DIRECTOR - -CAMANà QUADRANGLE - -(_Aplao_)] - -Yet another feature of the desert pampa are the “dry†valleys that join -the through-flowing streams at irregular intervals, as shown in the -accompanying regional diagram. If one follow a dry valley to its head -he will find there a set of broad and shallow tributaries. Sand drifts -may clog them and appear to indicate that water no longer flows through -them. They are often referred to by unscientific travelers as evidences -of a recent change of climate. I had once the unusual opportunity (in -the mountains of Chile) of seeing freshly fallen snow melted rapidly and -thus turned suddenly into the streams. In 1911 this happened also at San -Pedro de Atacama, northern Chile, right in the desert at 8,000 feet -(2,440 m.) elevation, and in both places the dry, sand-choked valleys -were cleaned out and definite channels reëstablished. From a large -number of facts like these we know that the dry valleys represent the -work of the infrequent rains. No desert is absolutely rainless, although -until recently it was the fashion to say so. Naturally the wind, which -works incessantly, partly offsets the work of the water. Yet the wind -can make but little impression upon the general outlines of the dry -valleys. They remain under the dominance of the irregular rains. These -come sometimes at intervals of three or four years, again at intervals -of ten to fifteen years, and some parts of the desert have probably been -rainless for a hundred years. Some specific cases are discussed in the -chapter on Climate. - -The large valleys of the desert zone have been cut by snow-fed streams -and then partly filled again so that deep waste lies on their floors and -abuts with remarkable sharpness against the bordering cliffs (Fig. 155). -Extensive flats are thus available for easy cultivation, and the -through-flowing streams furnish abundant water to the irrigating canals. -The alluvial floor begins almost at the foot of the steep western slope -of the lava plateau, but it is there stony and coarse--hence -Chuquibamba, or plain of stones (chuqui = stone; bamba = plain). Farther -down and about half-way between Chuquibamba and Aplao (Camaná -Quadrangle) it is partly covered with fresh mud and sand flows from the -bordering valley walls and the stream is intrenched two hundred feet. A -few miles above Aplao the stream emerges from its narrow gorge and -thenceforth flows on the surface of the alluvium right to the sea. -Narrow places occur between Cantas and Aplao, where there is a -projection of old and hard quartzitic rock, and again above Camaná, -where the stream cuts straight across the granite axis of the Coast -Range. Elsewhere the rock is either a softer sandstone or still -unindurated sands and gravels, as at the top of the desert series of -strata that are exposed on the valley wall. The changing width of the -valley is thus a reflection of the changing hardness of the rock. - -There is a wide range of products between Chuquibamba at 10,000 feet -(3,050 m.) at the head of the valley and Camaná near the valley mouth. -At the higher levels fruit will not grow--only alfalfa, potatoes, and -barley. A thousand feet below Chuquibamba fruit trees appear. Then -follows a barren stretch where there are mud flows and where the river -is intrenched. Below this there is a wonderful change in climate and -products. The elevation falls off 4,000 feet and the first cultivated -patches below the middle unfavorable section are covered with grape -vines. Here at 3,000 feet (900 m.) elevation above the sea begin the -famous vineyards of the Majes Valley, which support a wine industry that -dates back to the sixteenth century. Some of the huge buried earthenware -jars for curing the wine at Hacienda Cantas were made in the reign of -Philip II. - -The people of Aplao and Camaná are among the most hospitable and -energetic in Peru, as if these qualities were but the reflection of the -bounty of nature. Nowhere could I see evidences of crowding or of the -degeneracy or poverty that is so often associated with desert people. -Water is always plentiful; sometimes indeed too plentiful, for floods -and changes in the bed of the river are responsible for the loss of a -good deal of land. This abundance of water means that both the small and -the large landowners receive enough. There are none of the troublesome -official regulations, as in the poorer valleys with their inevitable -favoritism or downright graft. Yet even here the valley is not fully -occupied; at many places more land could be put under cultivation. The -Belaunde brothers at Cantas have illustrated this in their new cotton -plantation, where clearings and new canals have turned into cultivated -fields tracts long covered with brush. - -The Majes Valley sorely lacks an adequate port. Its cotton, sugar, and -wine must now be shipped to Camaná and thence to Mollendo, either by a -small bi-weekly boat, or by pack-train over the coast trail to Quilca, -where ocean steamers call. This is so roundabout a way that the planters -of the mid-valley section and the farmers of the valley head now export -their products over the desert trail from Cantas to Vitor on the -Mollendo-Arequipa railroad, whence they can be sent either to the cotton -mills or the stores of Arequipa, the chief distributing market of -southern Peru, or to the ocean port. - -The foreshore at Camaná is low and marshy where the salt water covers -the outer edge of the delta. In the hollow between two headlands a broad -alluvial plain has been formed, through which the shallow river now -discharges. Hence the natural indentation has been filled up and the -river shoaled. To these disadvantages must be added a third, the -shoaling of the sea bottom, which compels ships to anchor far off shore. -Such shoals are so rare on this dry and almost riverless coast as to be -a menace to navigation. The steamer _Tucapelle_, like all west-coast -boats, was sailing close to the unlighted shore on a very dark night in -April, 1911, when the usual fog came on. She struck the reef just off -Camaná. Half of her passengers perished in trying to get through the -tremendous surf that broke over the bar. The most practicable scheme for -the development of the port would seem to be a floating dock and tower -anchored out of reach of the surf, and connected by cable with a railway -on shore. Harbor works would be extraordinarily expensive. The valley -can support only a modest project. - -The relations of Fig. 65, representing the Camaná-Vitor region, are -typical of southern Peru, with one exception. In a few valleys the -streams are so small that but little water is ever found beyond the foot -of the mountains, as at Moquegua. In the Chili Valley is Arequipa (8,000 -feet), right at the foot of the big cones of the Maritime Cordillera -(see Fig. 6). The green valley floor narrows rapidly and cultivation -disappears but a few miles below the town. Outside the big valleys -cultivation is limited to the best spots along the foot of the Coast -Range, where tiny streams or small springs derive water from the zone of -clouds and fogs on the seaward slopes of the Coast Range. Here and there -are olive groves, a vegetable garden, or a narrow alfalfa meadow, -watered by uncertain springs that issue below the hollows of the -bordering mountains. - -[Illustration: FIG. 67--Irrigated and irrigable land in the Ica Valley -of the coastal desert of Peru.] - -[Illustration: FIG. 68--The projected canal to convey water from the -Atlantic slope to the Pacific slope of the Maritime Cordillera.[19]] - -In central and northern Peru the coastal region has aspects quite -different from those about Camaná. At some places, for example north of -Cerro Azul, the main spurs of the Cordillera extend down to the shore. -There is neither a low Coast Range nor a broad desert pampa. In such -places flat land is found only on the alluvial fans and deltas. Lima and -Callao are typical. Fig. 66, compiled from Adams’s reports on the water -resources of the coastal region of Peru, shows this distinctive feature -of the central region. Beyond Salaverry extends the northern region, -where nearly all the irrigated land is found some distance back from the -shore. The farther north we go the more marked is this feature, because -the coastal belt widens. Catacaos is several miles from the sea, and -Piura is an interior place. At the extreme north, where the rains begin, -as at Tumbez, the cultivated land once more extends to the coast. - -[Illustration: FIG. 69--A stream of the intermittent type in the coastal -desert of Peru. Depth of water in the Puira River at Puira, 1905. (Bol. -de Minas del Perú, 1906, No. 45, p. 2.)] - -[Illustration: FIG. 70--A stream of the perennial type in the coastal -desert of Peru. Depth of water in the Chira River at Sullana, 1905. Data -from May to September are approximate. (Bol. de Minas del Perú, 1906, -No. 45, p. 2.)] - -These three regions contain all the fertile coastal valleys of Peru. The -larger ones are impressive--with cities, railways, ports, and land in a -high state of cultivation. But they are after all only a few hundred -square miles in extent. They contain less than a quarter of the people. -The whole Pacific slope from the crest of the Cordillera has about -15,000 square miles (38,850 sq. km.), and of this only three per cent is -irrigated valley land, as shown in Fig. 66. Moreover, only a small -additional amount may be irrigated, perhaps one half of one per cent. -Even this amount may be added not only by a better use of the water but -also by the diversion of streams and lakes from the Atlantic to the -Pacific. Figs. 67 and 68 represent such a project, in which it is -proposed to carry the water of Lake Choclococha through a canal and -tunnel under the continental divide and so to the head of the Ica -Valley. A little irrigation can be and is carried on by the use of well -water, but this will never be an important source because of the great -depth to the ground water, and the fact that it, too, depends ultimately -upon the limited rains. - -The inequality of opportunity in the various valleys of the coastal -region depends in large part also upon inequality of river discharge. -This is dependent chiefly upon the sources of the streams, whether in -snowy peaks of the main Cordillera with fairly constant run-off, or in -the western spurs where summer rains bring periodic high water. A third -type has high water during the time of greatest snow melting, combined -with summer rains, and to this class belongs the Majes Valley with its -sources in the snow-cap of Coropuna. The other two types are illustrated -by the accompanying diagrams for Puira and Chira, the former -intermittent in flow, the latter fairly constant.[20] - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM DIRECTOR - -APLAO QUADRANGLE] - - - - -CHAPTER IX - -CLIMATOLOGY OF THE PERUVIAN ANDES - - -CLIMATIC BELTS - -The noble proportions of the Peruvian Andes and their position in -tropical latitudes have given them climatic conditions of great -diversity. Moreover, their great breadth and continuously lofty summits -have distributed the various climatic types over spaces sufficiently -ample to affect large and important groups of people. When we add to -this the fact that the topographic types developed on a large scale are -distributed at varying elevations, and that upon them depend to a large -degree the chief characteristics of the soil, another great factor in -human distribution, we are prepared to see that the Peruvian Andes -afford some striking illustrations of combined climatic and topographic -control over man. - -The topographic features in their relations to the people have been -discussed in preceding chapters. We shall now examine the corresponding -effects of climate. It goes without saying that the topographic and -climatic controls cannot and need not be kept rigidly apart. Yet it -seems desirable, for all their natural interdependence, to give them -separate treatment, since the physical laws upon which their -explanations depend are of course entirely distinct. Further, there is -an independent group of human responses to detailed climatic features -that have little or no connection with either topography or soil. - -The chief climatic belts of Peru run roughly from north to south in the -direction of the main features of the topography. Between 13° and 18° -S., however, the Andes run from northwest to southeast, and in short -stretches nearly west-east, with the result that the climatic belts -likewise trend westward, a condition well illustrated on the -seventy-third meridian. Here are developed important climatic features -not found elsewhere in Peru. The trade winds are greatly modified in -direction and effects; the northward-trending valleys, so deep as to be -secluded from the trades, have floors that are nearly if not quite arid; -a restricted coastal region enjoys a heavier rainfall; and the snowline -is much more strongly canted from west to east than anywhere else in the -long belt of mountains from Patagonia to Venezuela. These exceptional -features depend, however, upon precisely the same physical laws as the -normal climatic features of the Peruvian Andes. They can, therefore, be -more easily understood after attention has been given to the larger -aspects of the climatic problem of which they form a part. - -The critical relations of trade winds, lofty mountains, and ocean -currents that give distinction to Peruvian climate are shown in Figs. 71 -to 73. From them and Fig. 74 it is clear that the two sides of the -Peruvian mountains are in sharp contrast climatically. The eastern -slopes have almost daily rains, even in the dry season, and are clothed -with forest. The western leeward slopes are so dry that at 8,000 feet -even the most drought-resisting grasses stop--only low shrubs live below -this level, and over large areas there is no vegetation whatever. An -exception is the Coast Range, not shown on these small maps, but -exhibited in the succeeding diagram. These have moderate rains on their -seaward (westerly) slopes during some years and grass and shrubby -vegetation grow between the arid coastal terraces below them and the -parched desert above. The greatest variety of climate is enjoyed by the -mountain zone. Its deeper valleys and basins descend to tropical levels; -its higher ranges and peaks are snow-covered. Between are the climates -of half the world compressed, it may be, between 6,000 and 15,000 feet -of elevation and with extremes only a day’s journey apart. - -[Illustration: FIG. 71--The three chief topographic regions of Peru.] - -[Illustration: FIG. 72--The wind belts of Peru and ocean currents of -adjacent waters.] - -[Illustration: FIG. 73--The climatic belts of Peru.] - -[Illustration: FIG. 74--Belts of vegetation in Peru.] - -In the explanation of these contrasts we have to deal with relatively -simple facts and principles; but the reader who is interested chiefly in -the human aspects of the region should turn to p. 138 where the effects -of the climate on man are set forth. The ascending trades on the eastern -slopes pass successively into atmospheric levels of diminishing -pressure; hence they expand, deriving the required energy for expansion -from the heat of the air itself. The air thereby cooled has a lower -capacity for the retention of water vapor, a function of its -temperature; the colder the air the less water vapor it can take up. As -long as the actual amount of water vapor in the air is less than that -which the air can hold, no rain falls. But the cooling process tends -constantly to bring the warm, moist, ascending air currents to the limit -of their capacity for water vapor by diminishing the temperature. -Eventually the air is saturated and if the capacity diminishes still -further through diminishing temperature some of the water vapor must be -condensed from a gaseous to a liquid form and be dropped as rain. - -The air currents that rise thousands of feet per day on the eastern -slopes of the Andes pass again and again through this practically -continuous process and the eastern aspect of the mountains is kept -rain-soaked the whole year round. For the trades here have only the -rarest reversals. Generally they blow from the east day after day and -repeat a fixed or average type of weather peculiar to that part of the -tropics under their steady domination. During the southern summer, when -the day-time temperature contrasts between mountains and plains are -strongest, the force of the trade wind is greatly increased and likewise -the rapidity of the rain-making processes. Hence there is a distinct -seasonal difference in the rainfall--what we call, for want of a better -name, a “wet†and a “dry†season. - -On the western or seaward slopes of the Peruvian Andes the trade winds -descend, and the process of rain-making is reversed to one of -rain-taking. The descending air currents are compressed as they reach -lower levels where there are progressively higher atmospheric pressures. -The energy expended in the process is expressed in the air as heat, -whence the descending air gains steadily in temperature and capacity for -water vapor, and therefore is a drying wind. Thus the leeward, western -slopes of the mountains receive little rain and the lowlands on that -side are desert. - - -THE CLIMATE OF THE COAST - -A series of narrow but pronounced climatic zones coincide with the -topographic subdivisions of the western slope of the country between the -crest of the Maritime Cordillera and the Pacific Ocean. This belted -arrangement is diagrammatically shown in Fig. 75. From the zone of lofty -mountains with a well-marked summer rainy season descent is made by -lower slopes with successively less and less precipitation to the desert -strip, where rain is only known at irregular intervals of many years’ -duration. Beyond lies the seaward slope of the Coast Range, more or less -constantly enveloped in fog and receiving actual rain every few years, -and below it is the very narrow band of dry coastal terraces. - -[Illustration: FIG. 75--Topographic and climatic provinces in the -coastal region of Peru. The broadest division, into the zones of regular -annual rains and of irregular rains, occurs approximately at 8,000 feet -but is locally variable. To the traveler it is always clearly defined by -the change in architecture, particularly of the house roofs. Those of -the coast are flat; those of the sierra are pitched to facilitate run -off.] - -The basic cause of the general aridity of the region has already been -noted; the peculiar circumstances giving origin to the variety in detail -can be briefly stated. They depend upon the meteorologic and -hydrographic features of the adjacent portion of the South Pacific Ocean -and upon the local topography. - -The lofty Andes interrupt the broad sweep of the southeast trades -passing over the continent from the Atlantic; and the wind circulation -of the Peruvian Coast is governed to a great degree by the high pressure -area of the South Pacific. The prevailing winds blow from the south and -the southeast, roughly paralleling the coast or, as onshore winds, -making a small angle with it. When the Pacific high pressure area is -best developed (during the southern winter), the southerly direction of -the winds is emphasized, a condition clearly shown on the Pilot Charts -of the South Pacific Ocean, issued by the U.S. Hydrographic Office. - -[Illustration: FIG. 76--Temperatures at Callao, June-September, 1912, -from observations taken by Captain A. Taylor, of Callao. Air -temperatures are shown by heavy lines; sea temperatures by light lines. -In view of the scant record for comparative land and water temperatures -along the Peruvian coast this record, short as it is, has special -interest.] - -The hydrographic feature of greatest importance is the Humboldt Current. -To its cold waters is largely due the remarkably low temperatures of the -coast.[21] In the latitude of Lima its mean surface temperature is about -10° below normal. Lima itself has a mean annual temperature 4.6° F. -below the theoretical value for that latitude, (12° S.). An accompanying -curve shows the low temperature of Callao during the winter months. From -mid-June to mid-September the mean was 61° F., and the annual mean is -only 65.6° F. (18° C.). The reduction in temperature is accompanied by a -reduction in the vapor capacity of the super-incumbent air, an effect of -which much has been made in explanation of the west-coast desert. That -it is a contributing though not exclusive factor is demonstrated in Fig. -77. Curve _A_ represents the hypothetical change of temperature on a -mountainous coast with temporary afternoon onshore winds from a _warm_ -sea. Curve _B_ represents the change of temperature if the sea be cold -(actual case of Peru). The more rapid rise of curve _B_ to the right of -X-X′, the line of transition, and its higher elevation above its former -saturation level, as contrasted with _A_, indicates greater dryness -(lower relative humidity). There has been precipitation in case _A_, but -at a higher temperature, hence more water vapor remains in the air -after precipitation has ceased. Curve _B_ ultimately rises nearly to the -level of _A_, for with less water vapor in the air of case _B_ the -temperature rises more rapidly (a general law). Moreover, the higher the -temperature the greater the radiation. To summarize, curve _A_ rises -more slowly than curve _B_, (1) because of the greater amount of water -vapor it contains, which must have its temperature raised with that of -the air, and thus absorbs energy which would otherwise go to increase -the temperature of the air, and (2) because its loss of heat by -radiation is more rapid on account of its higher temperature. We -conclude from these principles and deductions that under the given -conditions a cold current intensifies, but does not cause the aridity of -the west-coast desert. - -[Illustration: FIG. 77--To show progressive lowering of saturation -temperature in a desert under the influence of the mixing process -whereby dry and cool air from aloft sinks to lower levels thus -displacing the warm surface air of the desert. The evaporated moisture -of the surface air is thus distributed through a great volume of upper -air and rain becomes increasingly rarer. Applied to deserts in general -it shows that the effect of any cosmic agent in producing climatic -change from moist to dry or dry to moist will be disproportionately -increased. The shaded areas C and C’ represent the fog-covered slopes of -the Coast Range of Peru as shown in Fig. 92. X-X’ represents the crest -of the Coast Range.] - -Curves _a_ and _b_ represent the rise of temperature in two contrasted -cases of warm and cold sea with the coastal mountains eliminated, so as -to simplify the principle applied to _A_ and _B_. The steeper gradient -of _b_ also represents the fact that the lower the initial temperature -the dryer will the air become in passing over the warm land. For these -two curves the transition line X-X’ coincides with the crest of the -Coast Range. It will also be seen that curve _a_ is never so far from -the saturation level as curve _b_. Hence, unusual atmospheric -disturbances would result in heavier and more frequent showers. - -[Illustration: FIG. 78--Wind roses for Callao. The figures for the -earlier period (1897-1900) are drawn from data in the BoletÃn de la -Sociedad Geográfica de Lima, Vols. 7 and 8, 1898-1900: for the latter -period data from observations of Captain A. Taylor, of Callao. The -diameter of the circle represents the proportionate number of -observations when calm was registered.] - -[Illustration: FIG. 79--Wind roses for Mollendo. The figures are drawn -from data in Peruvian Meteorology (1892-1895), Annals of the -Astronomical Observatory of Harvard College, Vol. 30, Pt. 2, Cambridge, -Mass., 1906. Observations for an earlier period, Feb. 1889-March 1890, -(Id. Vol. 39, Pt. 1, Cambridge, Mass. 1890) record S. E. wind at 2 p. m. -97 per cent of the observation time.] - -[Illustration: FIG. 80--Wind roses for the summer and winter seasons of -the years 1911-1913. The diameter of the circle in each case shows the -proportion of calm. Figures are drawn from data in the Anuario -Meteorológico de Chile, Publications No. 3, (1911), 6 (1912) and 13 -(1913), Santiago, 1912, 1914, 1914.] - -Turning now to local factors we find on the west coast a regional -topography that favors a diurnal periodicity of air movement. The strong -slopes of the Cordillera and the Coast Range create up-slope or eastward -air gradients by day and opposite gradients by night. To this -circumstance, in combination with the low temperature of the ocean water -and the direction of the prevailing winds, is due the remarkable -development of the sea-breeze, without exception the most important -meteorological feature of the Peruvian Coast. Several graphic -representations are appended to show the dominance of the sea-breeze -(see wind roses for Callao, Mollendo, Arica, and Iquique), but interest -in the phenomenon is far from being confined to the theoretical. -Everywhere along the coast the _virazon_, as the sea-breeze is called in -contradistinction to the _terral_ or land-breeze, enters deeply into the -affairs of human life. According to its strength it aids or hinders -shipping; sailing boats may enter port on it or it may be so violent, -as, for example, it commonly is at Pisco, that cargo cannot be loaded or -unloaded during the afternoon. On the nitrate pampa of northern Chile -(20° to 25° S.) it not infrequently breaks with a roar that heralds its -coming an hour in advance. In the Majes Valley (12° S.) it blows gustily -for a half-hour and about noon (often by eleven o’clock) it settles down -to an uncomfortable gale. For an hour or two before the sea-breeze -begins the air is hot and stifling, and dust clouds hover about the -traveler. The maximum temperature is attained at this time and not -around 2.00 P. M. as is normally the case. Yet so boisterous is the noon -wind that the laborers time their siesta by it, and not by the high -temperatures of earlier hours. In the afternoon it settles down to a -steady, comfortable, and dustless wind, and by nightfall the air is once -more calm. - -[Illustration: FIG. 81--Wind roses for Iquique for the summer and winter -seasons of the years 1911-1913. The diameter of the circle in each case -shows the proportion of calm. For source of data see Fig. 80.] - -Of highest importance are the effects of the sea-breeze on -precipitation. The bold heights of the Coast Range force the nearly or -quite saturated air of the sea-wind to rise abruptly several thousand -feet, and the adiabatic cooling creates fog, cloud, and even rain on the -seaward slope of the mountains. The actual form and amount of -precipitation both here and in the interior region vary greatly, -according to local conditions and to season and also from year to year. -The coast changes height and contour from place to place. At Arica the -low coastal chain of northern Chile terminates at the Morro de Arica. -Thence northward is a stretch of open coast, with almost no rainfall and -little fog. But in the stretch of coast between Mollendo and the Majes -Valley a coastal range again becomes prominent. Fog enshrouds the hills -almost daily and practically every year there is rain somewhere along -their western aspect. - -[Illustration: FIG. 82--The wet and dry seasons of the Coast Range and -the Cordillera are complementary in time. The “wet†season of the former -occurs during the southern winter; the cloud bank on the seaward slopes -of the hills is best developed at that time and actual rains may occur.] - -[Illustration: FIG. 83--During the southern summer the seaward slopes of -the Coast Range are comparatively clear of fog. Afternoon cloudiness is -characteristic of the desert and increases eastward (compare Fig. 86), -the influence of the strong sea winds as well as that of the trades -(compare Fig. 93B) being felt on the lower slopes of the Maritime -Cordillera.] - -During the southern winter the cloud bank of the coast is best developed -and precipitation is greatest. At Lima, for instance, the clear skies of -March and April begin to be clouded in May, and the cloudiness grows -until, from late June to September, the sun is invisible for weeks at a -time. This is the period of the garua (mist) or the “tiempo de lomas,†-the “season of the hills,†when the moisture clothes them with verdure -and calls thither the herds of the coast valleys. - -[Illustration: FIG. 84--Cloudiness at Callao. Figures are drawn from -data in the BoletÃn de la Sociedad Geográfica de Lima, Vols. 7 and 8, -1898-1900. They represent the conditions at three observation hours -during the summers (Dec., Jan.) of 1897-1898, 1898-1899, 1899-1900 and -the winters (June, July) of 1898 and 1899.] - -During the southern summer on account of the greater relative difference -between the temperatures of land and water, the sea-breeze attains its -maximum strength. It then accomplishes its greatest work in the desert. -On the pampa of La Joya, for example, the sand dunes move most rapidly -in the summer. According to the Peruvian Meteorological Records of the -Harvard Astronomical Observatory the average movement of the dunes from -April to September, 1900, was 1.4 inches per day, while during the -summer months of the same year it was 2.7 inches. In close agreement are -the figures for the wind force, the record for which also shows that 95 -per cent of the winds with strength over 10 miles per hour blew from a -southerly direction. Yet during this season the coast is generally -clearest of fog and cloud. The explanation appears to lie in the -exceedingly delicate nature of the adjustments between the various -rain-making forces. The relative humidity of the air from the sea is -always high, but on the immediate coast is slightly less so in summer -than in winter. Thus in Mollendo the relative humidity during the winter -of 1895 was 81 per cent; during the summer 78 per cent. Moreover, the -temperature of the Coast Range is considerably higher in summer than in -winter, and there is a tendency to reëvaporation of any moisture that -may be blown against it. The immediate shore, indeed, may still be -cloudy as is the case at Callao, which actually has its cloudiest season -in the summer but the hills are comparatively clear. In consequence the -sea-air passes over into the desert, where the relative increase in -temperature has not been so great (compare Mollendo and La Joya in the -curve for mean monthly temperature), with much higher vapor content than -in winter. The relative humidity for the winter season at La Joya, 1895, -was 42.5 per cent; for the summer season 57 per cent. The influence of -the great barrier of the Maritime Cordillera, aided doubtless by -convectional rising, causes ascent of the comparatively humid air and -the formation of cloud. Farther eastward, as the topographic influence -is more strongly felt, the cloudiness increases until on the border -zone, about 8,000 feet in elevation, it may thicken to actual rain. Data -have been selected to demonstrate this eastern gradation of -meteorological phenomena. - -[Illustration: FIG. 85--Temperature curves for Mollendo (solid lines) -and La Joya (broken lines) April, 1894, to December, 1895, drawn from -data in Peruvian Meteorology, 1892-1895, Annals of the Astronomical -Observatory of Harvard College, Vol. 49, Pt. 2, Cambridge, Mass., 1908. -The approximation of the two curves of maximum temperature during the -winter months contrasts with the well-maintained difference in minimum -temperatures throughout the year.] - -[Illustration: FIG. 86--Mean monthly cloudiness for Mollendo (solid -line) and La Joya (broken line) from April, 1892, to December, 1895. -Mollendo, 80 feet elevation, has the maximum winter cloudiness -characteristic of the seaward slope of the Coast Range (compare Fig. 82) -while the desert station of La Joya, 4,140 feet elevation, has typical -summer cloudiness (compare Fig. 83). Figures are drawn from data in -Peruvian Meteorology, 1892-1895, Annals of the Astronomical Observatory -of Harvard College, Vol. 49, Pt. 2, Cambridge, Mass., 1908.] - -[Illustration: FIG. 87--Wind roses for La Joya for the period April, -1892, to December, 1895. Compare the strong afternoon indraught from the -south with the same phenomenon at Mollendo, Fig. 79. Figures drawn from -data in Peruvian Meteorology, 1892-1895, Annals of the Astronomical -Observatory of Harvard College, Vol. 39, Pt. 2, Cambridge, Mass., 1906.] - -At La Joya, a station on the desert northeast of Mollendo at an -elevation of 4,140 feet, cloudiness is always slight, but it increases -markedly during the summer. Caraveli, at an altitude of 5,635 feet,[22] -and near the eastern border of the pampa, exhibits a tendency toward the -climatic characteristics of the adjacent zone. Data for a camp station -out on the pampa a few leagues from the town, were collected by Mr. J. -P. Little of the staff of the Peruvian Expedition of 1912-13. They -relate to the period January to March, 1913. Wind roses for these months -show the characteristic light northwesterly winds of the early morning -hours, in sharp contrast with the strong south and southwesterly -indraught of the afternoon. The daily march of cloudiness is closely -coördinated. Quotations from Mr. Little’s field notes follow: - -“In the morning there is seldom any noticeable wind. A breeze starts at -10 A. M., generally about 180° (i. e. due south), increases to 2 or 3 -velocity at noon, having veered some 25° to the southwest. It reaches a -maximum velocity of 3 to 4 at about 4.00 P. M., now coming about 225° -(i. e. southwest). By 6 P. M. the wind has died down considerably and -the evenings are entirely free from it. The wind action is about the -same every day. It is not a cold wind and, except with the fog, not a -damp one, for I have not worn a coat in it for three weeks. It has a -free unobstructed sweep across fairly level pampas.... At an interval of -every three or four days a dense fog sweeps up from the southwest, dense -enough for one to be easily lost in it. It seldom makes even a sprinkle -of rain, but carries heavy moisture and will wet a man on horseback in -10 minutes. It starts about 3 P.M. and clears away by 8.00 P. M..... -During January, rain fell in camp twice on successive days, starting at -3.00 P. M. and ceasing at 8.00 P. M. It was merely a light, steady rain, -more the outcome of a dense fog than a rain-cloud of quick approach. In -Caraveli, itself, I am told that it rains off and on all during the -month in short, light showers.†This record is dated early in February -and, in later notes, that month and March are recorded rainless. - -[Illustration: FIG. 88--Wind roses for a station on the eastern border -of the Coast Desert near Caraveli during the summer (January to March) -of 1913. Compare with Fig. 87. The diameter of the circle in each case -represents the proportion of calm. Note the characteristic morning -calm.] - -Chosica (elevation 6,600 feet), one of the meteorological stations of -the Harvard Astronomical Observatory, is still nearer the border. It -also lies farther north, approximately in the latitude of Lima, and this -in part may help to explain the greater cloudiness and rainfall. The -rainfall for the year 1889-1890 was 6.14 inches, of which 3.94 fell in -February. During the winter months when the principal wind observations -were taken, over 90 per cent showed noon winds from a southerly -direction while in the early morning northerly winds were frequent. It -is also noteworthy that the “directions of the upper currents of the -atmosphere as recorded by the motion of the clouds was generally between -N. and E.†Plainly we are in the border region where climatic influences -are carried over from the plateau and combine their effects with those -from Pacific sources. Arequipa, farther south, and at an altitude of -7,550 feet, resembles Chosica. For the years 1892 to 1895 its mean -rainfall was 5.4 inches. - -[Illustration: FIG. 89--Cloudiness at the desert station of Fig. 88 -(near Caraveli), for the summer (January to March) of 1913.] - -Besides the seasonal variations of precipitation there are longer -periodic variations that are of critical importance on the Coast Range. -At times of rather regular recurrence, rains that are heavy and general -fall there. Every six or eight years is said to be a period of rain, but -the rains are also said to occur sometimes at intervals of four years or -ten years. The regularity is only approximate. The years of heaviest -rain are commonly associated with an unusual frequency of winds from the -north, and an abnormal development of the warm current, El Niño, from -the Gulf of Guayaquil. Such was the case in the phenomenally rainy year -of 1891. The connection is obscure, but undoubtedly exists. - -The effects of the heavy rains are amazing and appear the more so -because of the extreme aridity of the country east of them. During the -winter the desert traveler finds the air temperature rising to -uncomfortable levels. Vegetation of any sort may be completely lacking. -As he approaches the leeward slope of the Coast Range, a cloud mantle -full of refreshing promise may be seen just peeping over the crest (Fig. -91). Long, slender cloud filaments project eastward over the margin of -the desert. They are traveling rapidly but they never advance far over -the hot wastes, for their eastern margins are constantly undergoing -evaporation. At times the top of the cloud bank rises well above the -crest of the Coast Range, and it seems to the man from the temperate -zone as if a great thunderstorm were rising in the west. But for all -their menace of wind and rain the clouds never get beyond the desert -outposts. In the summer season the aspect changes, the heavy yellow sky -of the desert displaces the murk of the coastal mountains and the -bordering sea. - -[Illustration: FIG. 90--Cloudiness at Chosica, July, 1889, to September, -1890. Chosica, a station on the Oroya railroad east of Lima, is situated -on the border region between the desert zone of the coast and the -mountain zone of yearly rains. The minimum cloudiness recorded about 11 -a. m. is shown by a broken line; the maximum cloudiness, about 7 p. m., -by a dotted line, and the mean for the 24 hours by a heavy solid line. -The curves are drawn from data in Peruvian Meteorology, 1889-1890, -Annals of the Astronomical Observatory of Harvard College, Vol. 39, Pt. -1, Cambridge, Mass., 1899.] - -It is an age-old strife renewed every year and limited to a narrow field -of action, wonderfully easy to observe. We saw it in its most striking -form at the end of the winter season in October, 1911, and for more than -a day watched the dark clouds rise ominously only to melt into nothing -where the desert holds sway. At night we camped beside a scum-coated -pool of alkali water no larger than a wash basin. It lay in a valley -that headed in the Coast Range, and carried down into the desert a mere -trickle that seeped through the gravels of the valley floor. A little -below the pool the valley cuts through a mass of granite and becomes a -steep-walled gorge. The bottom is clogged with waste, here boulders, -there masses of both coarse and fine alluvium. The water in the valley -was quite incapable of accomplishing any work except that associated -with solution and seepage, and we saw it in the wet season of an -unusually wet year. Clearly there has been a diminution in the water -supply. But time prevented us from exploring this particular valley to -its head, to see if the reduction were due to a change of climate, or -only to capture of the head-waters by the vigorous rain-fed streams that -enjoy a favorable position on the wet seaward slopes and that are -extending their watershed aggressively toward the east at the expense of -their feeble competitors in the dry belt. - -An early morning start enabled me to witness the whole series of changes -between the clear night and the murky day, and to pass in twelve hours -from the dry desert belt through the wet belt, and emerge again into the -sunlit terraces at the western foot of the Coast Range. Two hours before -daylight a fog descended from the hills and the going seemed to be -curiously heavy for the beasts. At daybreak my astonishment was great to -find that it was due to the distinctly moist sand. We were still in the -desert. There was not a sign of a bush or a blade of grass. Still, the -surface layer, from a half inch to an inch thick, was really wet. The -fog that overhung the trail lifted just before sunrise, and at the first -touch of the sun melted away as swiftly as it had come. With it went the -surface moisture and an hour after sunrise the dust was once more rising -in clouds around us. - -We had no more than broken camp that morning when a merchant with a -pack-train passed us, and shouted above the bells of the leading animals -that we ought to hurry or we should get caught in the rain at the pass. -My guide, who, like many of his kind, had never before been over the -route he pretended to know, asked him in heaven’s name what drink in -distant Camaná whence he had come produced such astonishing effects as -to make a man talk about rain in a parched desert. We all fell to -laughing and at our banter the stranger stopped his pack-train and -earnestly urged us to hurry, for, he said, the rains beyond the pass -were exceptionally heavy this year. We rode on in a doubtful state of -mind. I had heard about the rains, but I could not believe that they -fell in real showers! - -About noon the cloud bank darkened and overhung the border of the -desert. Still the sky above us was clear. Then happened what I can yet -scarcely believe. We rode into the head of a tiny valley that had cut -right across the coast chain. A wisp of cloud, an outlier of the main -bank, lay directly ahead of us. There were grass and bushes not a -half-mile below the bare dry spot on which we stood. We were riding down -toward them when of a sudden the wind freshened and the cloud wisp -enveloped us, shutting out the view, and ten minutes later the moisture -had gathered in little beads on the manes of our beasts and the trail -became slippery. In a half-hour it was raining and in an hour we were in -the midst of a heavy downpour. We stopped and pastured our famished -beasts in luxuriant clover. While they gorged themselves a herd of -cattle drifted along, and a startled band of burros that suddenly -confronted our beasts scampered out of sight in the heavy mist. Later we -passed a herdsman’s hut and long before we reached him he shouted to us -to alter our course, for just ahead the old trail was wet and -treacherous at this time of year. The warning came too late. Several of -our beasts lost their footing and half rolled, half slid, down hill. One -turned completely over, pack and all, and lay in the soft mud calmly -taking advantage of the delay to pluck a few additional mouthfuls of -grass. We were glad to reach firmer ground on the other side of the -valley. - -The herdsmen were a hospitable lot. They had come from Camaná and rarely -saw travelers. Their single-roomed hut was mired so deeply that one -found it hard to decide whether to take shelter from the rain inside or -escape the mud by standing in the rain outside. They made a little -so-called cheese, rounded up and counted the cattle on clear days, -drove them to the springs from time to time, and talked incessantly of -the wretched rains in the hills and the delights of dry Camaná down on -the coast. We could not believe that only some hours’ traveling -separated two localities so wholly unlike. - -The heavy showers and luxuriant pastures of the wet years and the light -local rains of the dry years endow the Coast Range with many peculiar -geographic qualities. The heavy rains provide the desert people at the -foot of the mountains such a wealth of pasture for their burdensome -stock as many oases dwellers possess only in their dreams. From near and -far cattle are driven to the wet hill meadows. Some are even brought in -from distant valleys by sea, yet only a very small part of the rich -pastures can be used. It is safe to say that they could comfortably -support ten times the number of cattle, mules, and burros that actually -graze upon them. The grass would be cut for export if the weather were -not so continually wet and if there were not so great a mixture of -weeds, flowers, and shrubs. - -Then come the dry years. The surplus stock is sold, and what remains is -always maintained at great expense. In 1907 I saw stock grazing in a -small patch of dried vegetation back of Mollendo, although they had to -be driven several miles to water. They looked as if they were surviving -with the greatest difficulty and their restless search for pasture was -like the search of a desperate hunter of game. In 1911 the same tract -was quite devoid of grass, and except for the contour-like trails that -completely covered the hills no one would even guess that this had -formerly been a cattle range. The same year, but five months later, a -carpet of grass, bathed in heavy mist, covered the soil; a trickle of -water had collected in pools on the valley floor; several happy families -from the town had laid out a prosperous-looking garden; there were -romping children who showed me where to pick up the trail to the port; -on every hand was life and activity because the rains had returned -bringing plenty in their train. I asked a native how often he was -prosperous. - -“Segun el temporal y la Providencia†(according to the weather and to -Providence), he replied, as he pointed significantly to the pretty green -hills crowned with gray mist. - -It, therefore, seems fortunate that the Coast Range is so placed as to -intercept and concentrate a part of the moisture that the sea-winds -carry, and doubly fortunate that its location is but a few miles from -the coast, thereby giving temporary relief to the relatively crowded -people of the lower irrigated valleys and the towns. The wet years -formerly developed a crop of prospectors. Pack animals are cheaper when -there is good pasture and they are also easier to maintain. So when the -rains came the hopeful pick-and-shovel amateurs began to emigrate from -the towns to search for ore among the discolored bands of rock intruded -into the granite masses of the coastal hills. However, the most likely -spots have been so thoroughly and so unsuccessfully prospected for many -years that there is no longer any interest in the “mines.†- -Transportation rates are still most intimately related to the rains. My -guide had two prices--a high price if I proposed to enter a town at -night and thus require him to buy expensive forage; a low price if I -camped in the hills and reached the town in time for him to return to -the hills with his animals. Inquiry showed that this was the regular -custom. I also learned that in packing goods from one part of the coast -to another forage must be carried in dry years or the beasts required to -do without. In wet years by a very slight detour the packer has his -beasts in good pasture that is free for all. The merchant who dispatches -the goods may find his charges nearly doubled in extremely dry years. -Goods are more expensive and there is a decreased consumption. The -effects of the rains are thus transmitted from one to another, until at -last nearly all the members of a community are bearing a share of the -burdens imposed by drought. As always there are a few who prosper in -spite of the ill wind. If the pastures fail, live stock _must_ be sold -and the dealers ship south to the nitrate ports or north to the large -coast towns of Peru, where there is always a demand. Their business is -most active when it is dry or rather at the beginning, of the dry -period. Also if transport by land routes becomes too expensive the small -traders turn to the sea routes and the carriers have an increased -business. But so far as I have been able to learn, dry years favor only -a few scattered individuals. - -To the traveler on the west coast it is a source of constant surprise -that the sky is so often overcast and the ports hidden by fog, while on -every hand there are clear evidences of extreme aridity. Likewise it is -often inquired why the sunsets there should be often so superlatively -beautiful during the winter months when the coast is fog bound. Why a -desert when the air is so humid? Why striking sunsets when so many of -the days are marked by dull skies? As we have seen in the first part of -this chapter, the big desert tracts lie east of the Coast Range, and -there, excepting slight summer cloudiness, cloudless skies are the rule. -The desert just back of the coast is in many parts of Peru only a narrow -fringe of dry marine terraces quite unlike the real desert in type of -weather and in resources. The fog bank overhanging it forms over the -Humboldt Current which lies off shore; it drifts landward with the -onshore wind; it forms over the upwelling cold water between the current -and the shore; it gathers on the seaward slopes of the coastal hills as -the inflowing air ascends them in its journey eastward. Sometimes it -lies on the surface of the land and the water; more frequently it is -some distance above them. On many parts of the coast its characteristic -position is from 2,000 to 4,000 feet above sea level, descending at -night nearly or quite to the surface, ascending by day and sometimes all -but disappearing except as rain-clouds on the hills.[23] Upon the local -behavior of the fog bank depends in large measure the local climate. A -general description of the coastal climate will have many exceptions. -The physical principles involved are, however, the same everywhere. I -take for discussion therefore the case illustrated by Fig. 92, since -this also displays with reasonable fidelity the conditions along that -part of the Peruvian coast between Camaná and Mollendo which lies in the -field of work of the Yale Peruvian Expedition of 1911. - -Three typical positions of the fog bank are shown in the figure, and a -fourth--that in which the bank extends indefinitely westward--may be -supplied by the imagination. - -If the cloud bank be limited to _C_ only the early morning hours at the -port are cloudy. If it extend to _B_ the sun is obscured until midday. -If it reach as far west as _A_ only a few late afternoon hours are -sunny. Once in a while there is a sudden splash of rain--a few drops -which astonish the traveler who looks out upon a parched landscape. The -smaller drops are evaporated before reaching the earth. In spite of the -ever-present threat of rain the coast is extremely arid. Though the -vegetation appears to be dried and burned up, the air is humid and for -months the sky may be overcast most of the time. So nicely are the -rain-making conditions balanced that if one of our ordinary low-pressure -areas, or so-called cyclonic storms, from the temperate zone were set in -motion along the foot of the mountains, the resulting deluge would -immediately lay the coast in ruins. The cane-thatched, mud-walled huts -and houses would crumble in the heavy rain like a child’s sand pile -before a rising sea; the alluvial valley land would be coated with -infertile gravel; and mighty rivers of sand, now delicately poised on -arid slopes, would inundate large tracts of fertile soil. - -[Illustration: FIG. 91--Looking down the canyon of the Majes River to -the edge of the cloud bank formed against the Coast Range back of -Camaná.] - -[Illustration: FIG. 92--Topographic and climatic cross-section to show -the varying positions of the cloud bank on the coast of Peru, the dry -terrace region, and the types of stream profiles in the various belts.] - -If the fog and cloud bank extend westward indefinitely, the entire day -may be overcast or the sun appear for a few moments only through -occasional rifts. Generally, also, it will make an appearance just -before sunset, its red disk completely filling the narrow space between -the under surface of the clouds and the water. I have repeatedly seen -the ship’s passengers and even the crew leave the dinner table and -collect in wondering groups about the port-holes and doorways the better -to see the marvelous play of colors between sky and sea. It is -impossible not to be profoundly moved by so majestic a scene. A long -resplendent path of light upon the water is reflected in the clouds. -Each cloud margin is tinged with red and, as the sun sinks, the long -parallel bands of light are shortened westward, changing in color as -they go, until at last the full glory of the sunset is concentrated in a -blazing arc of reds, yellows, and purples, that to most people quite -atones for the dull gray day and its humid air. - -At times the clouds are broken up by the winds and scattered -helter-skelter through the west. A few of them may stray into the path -of the sun temporarily to hide it and to reflect its primary colors when -the sun reappears. From the main cloud masses there reach out slender -wind-blown streamers, each one delicately lighted as the sun’s rays -filter through its minute water particles. Many streamers are visible -for only a short distance, but when the sun catches them their filmy -invisible fingers become delicate bands of light, some of which rapidly -grow out almost to the dome of the sky. Slowly they retreat and again -disappear as the rays of the sun are gradually shut off by the upturning -curve of the earth. - -The unequal distribution of precipitation in the climatic zones of -western Peru has important hydrographic consequences. These will now be -considered. In the preceding figure four types of stream profiles are -displayed and each has its particular relation to the cloud bank. Stream -1 is formed wholly upon the coastal terraces beneath the cloud bank. It -came into existence only after the uplift of the earth’s crust that -brought the wave-cut platforms above sea level. It is extremely youthful -and on account first of the small seepage at its headquarters--it is -elsewhere wholly without a tributary water supply--and, second, of the -resistant granite that occurs along this part of the coast, it has very -steep and irregular walls and an ungraded floor. Many of these -“quebradas†are difficult to cross. A few of them have fences built -across their floors to prevent the escape of cattle and burros that -wander down from the grassy hills into the desert zone. Others are -partitioned off into corrals by stone fences, the steep walls of the -gorge preventing the escape of the cattle. To these are driven the -market cattle, or mules and burros that are required for relays along -the shore trail. - -Stream 2 heads in the belt of rains. Furthermore it is a much older -stream than 1, since it dates back to the time when the Coast Range was -first formed. It has ample tributary slopes and a large number of small -valleys. A trickle of water flows down to become lost in the alluvium of -the lower part of the valley or to reappear in scattered springs. Where -springs and seepage occur together, an olive grove or a garden marks the -spot, a corral or two and a mud or stone or reed hut is near by, and -there is a tiny oasis. Some of these dots of verdure become so dry -during a prolonged drought that the people, long-established, move away. -To others the people return periodically. Still others support permanent -settlements. - -Stream 3 has still greater age. Its only competitors are the feeble, -almost negligible, streams that at long intervals flow east toward the -dry zone. Hence it has cut back until it now heads in the desert. Its -widely branched tributaries gather moisture from large tracts. There is -running water in the valley floor even down in the terrace zone. At -least there are many dependable springs and the permanent homes that -they always encourage. A valley of this type is always marked by a -well-defined trail that leads from settlement to settlement and eastward -over the “pass†to the desert and the Andean towns. - -Stream 4 is a so-called “antecedent†stream. It existed before the Coast -Range was uplifted and cut its channel downward as the mountains rose in -its path. The stretch where it crosses the mountains may be a canyon -with a narrow, rocky, and uncultivable floor, so that the valley trails -rise to a pass like that at the head of stream 3, and descend again to -the settlements at the mouth of 4. There is in this last type an -abundance of water, for the sources of the stream are in the zone of -permanent snows and frequent winter rains of the lofty Cordillera of the -Andes. The settlements along this stream are continuous, except where -shut-ins occur--narrow, rocky defiles caused by more resistant rock -masses in the path of the stream. Here and there are villages. The -streams have fish. When the water rises the river may be unfordable and -people on opposite sides must resort to boats or rafts.[24] - - -EASTERN BORDER CLIMATES - -On windward mountain slopes there is always a belt of maximum -precipitation whose elevation and width vary with the strength of the -wind, with the temperature, and with the topography. A strong and -constant wind will produce a much more marked concentration of the -rainfall. The belt is at a low elevation in high latitudes and at a high -elevation in low latitudes, with many irregularities of position -dependent upon the local and especially the minimum winter temperature. -The topographic controls are important, since the rain-compelling -elevation may scatter widely the localities of maximum precipitation or -concentrate them within extremely narrow limits. The human effects of -these climatic conditions are manifold. Wherever the heaviest rains are, -there, too, as a rule, are the densest forests and often the most -valuable kinds of trees. If the general climate be favorable and the -region lie near dense and advanced populations, exploitation of the -forest and progress of the people will go hand in hand. If the region be -remote and some or all of the people in a primitive state, the forest -may hinder communication and retard development, especially if it lie in -a hot zone where the natural growth of population is slow.... These are -some of the considerations we shall keep in mind while investigating the -climate of the eastern border of the Peruvian Andes. - -[Illustration: FIG. 93A--Cloud types and rainfall belts on the eastern -border of the Peruvian Andes in the dry season, southern winter. The -zone of maximum rainfall extends approximately from 4,000 to 10,000 feet -elevation.] - -[Illustration: FIG. 93B--Cloud types and rainfall belts on the eastern -border of the Peruvian Andes in the wet season, southern summer.] - -The belt of maximum precipitation on the eastern border of the Andean -Cordillera in Peru lies between 4,000 and 10,000 feet. Judging by the -temporary records of the expedition and especially by the types of -forest growth, the heaviest rains occur around 8,000 feet. It is between -these elevations that the densest part of the Peruvian _montaña_ -(forest) is found. The cold timber line is at 10,500 feet with -exceptional extensions of a few species to 12,500 feet. In basins or -deep secluded valleys near the mountain border, a dry timber line occurs -at 3,000 feet with many variations in elevation due to the variable -declivity and exposure of the slopes and degree of seclusion of the -valleys. Elsewhere, the mountain forest passes without a break into the -plains forest with change in type but with little change in density. The -procumbent and suppressed trees of the cold timber line in regions of -heavy winter snows are here absent, for the snows rarely reach below -14,000 feet and even at that elevation they are only light and -temporary. The line of perpetual snow is at 15,000 feet. This permanent -gap of several thousand feet vertical elevation between the zone of snow -and the zone of forest permits the full extension of many pioneer forest -species, which is to say, there is an irregular development of the cold -timber line. It also permits the full use of the pasture belt above the -timber (Fig. 97), hence permanent habitations exist but little below the -snowline and a group of distinctive high-mountain folk enjoys a wide -distribution. There is a seasonal migration here, but it is not -wholesale; there are pastures snow-covered in the southern winter, but, -instead of the complete winter burial of the Alpine meadows of our -western mountains, we have here only a buried upper fringe. All the rest -of the pasture belt is open for stock the year round. - -This climatic distinction between the lofty grazing lands of the tropics -and those of the temperate zones is far-reaching. Our mountain forests -are not utilized from above but from below. Furthermore, the chief ways -of communication lead around our forests, or, if through them, only for -the purpose of putting one population group in closer touch with -another. In the Peruvian Andes the largest population groups live above -the forest, not below it or within it. It must be and is exploited from -above. - -Hence railways to the eastern valleys of Peru have two chief objects, -(1) to get the plantation product to the dense populations above the -forest and (2) to bring timber from the _montaña_ to the treeless -plateau. The mountain prospector is always near a habitation; the rubber -prospector goes down into the forested valleys and plains far from -habitations. The forest separates the navigable streams from the chief -towns of the plateau; it does not lead down to rich and densely -populated valley floors. - -Students in eastern Peru should find it a little difficult to understand -poetical allusions to silent and lonely highlands in contrast to the -busy life of the valleys. To them Shelley’s description of the view from -the Euganean Hills of northern Italy, - - “Beneath is spread like a green sea - The waveless plain of Lombardy, ... - Islanded by cities fair,†- -might well seem to refer to a world that is upside down. - -There is much variation in the forest types between the mountains and -the plains. At the top of the forest zone the warm sunny slopes have a -forest cover; the shady slopes are treeless. At the lower edge of the -grassland, only the shady slopes are forested (Fig. 53B). Cacti of -arboreal size and form grow on the lofty mountains far above the limits -of the true forest; they also appear at 3,000 feet in modified form, -large, rank, soft-spined, and in dense stands on the semi-arid valley -floors below the dry timber line. Large tracts between 8,000 and 10,000 -feet are covered with a forest growth distributed by species--here a -dense stand of one type of tree, there another. This is the most -accessible part of the Peruvian forest and along the larger valleys it -is utilized to some extent. The number of species is more limited, -however, and the best timber trees are lower down. Though often referred -to as jungle, the lowlier growths at the upper edge of the forest zone -have no resemblance to the true jungle that crowds the lowland forest. -They are merely an undergrowth, generally open, though in some places -dense. They are nowhere more dense than many examples from New England -or the West. - -Where deep valleys occur near the border of the mountains there is a -semi-arid climate below and a wet climate above, with a correspondingly -greater number of species within short distances of each other. This is -a far more varied forest than at the upper edge of the timber zone or -down on the monotonous plains. It has a higher intrinsic value than any -other. That part of it between the Pongo and Yavero (1,200 to 4,000 -feet) is very beautiful, with little undergrowth except a light -ground-cover of ferns. The trees are from 40 to 100 feet in height with -an average diameter of about 15 inches. It would yield from 3,000 to -5,000 board feet per acre exclusive of the palms. There are very few -vines suspended from the forest crown and the trunks run clear from 30 -to 60 feet above the ground. Were there plenty of labor and a good -transportation line, these stands would have high economic value. Among -the most noteworthy trees are the soft white cedar, strong and light; -the amarillo and the sumbayllo, very durable in water; the black nogal, -and the black balsam, straight and easy to work; the heavy yunquero, -which turns pink when dry; the chunta or black palm, so hard and -straight and easy to split that wooden nails are made from it; and the -rarer sandy matico, highly prized for dug-out canoes. Also from the -chunta palm, hollow except for a few central fibers, easily removed, -pipes are made to convey water. The cocobolo has a rich brown color and -a glossy surface and is very rare, hence is much sought after for use in -furniture making. Most of these woods take a brilliant polish and -exhibit a richness and depth of color and a beauty of grain that are -rare among our northern woods. - -[Illustration: FIG. 94--Cloud belt at 11,000 feet in the Apurimac Canyon -near Incahuasi. For a regional diagram and a climatic cross-section see -Figs. 32 and 33.] - -[Illustration: FIG. 95--The tropical forest near Pabellon on the slopes -of the Urubamba Valley. Elevation 3,000 feet (915 m.).] - -The plains forest northeast of the mountains is in the zone of moderate -rainfall where there is one long dry season and one long wet season. -When it is dry the daytime temperatures rise rapidly to such high levels -that the relative humidity of the air falls below 50 per cent (Fig. -110). The effect on the vegetation is so marked that many plants pass -into a distinctly wilted condition. On clear days the rapid fall in the -relative humidity is astonishing. By contrast the air on the mountain -border heats more slowly and has a higher relative humidity, because -clouds form almost constantly in the ascending air currents and reflect -and absorb a large part of the heat of the sun’s rays. It is striking to -find large tracts of cane and bamboo on the sand bars and on wet shady -hillslopes in the slope belt, and to pass out of them in going to the -plains with which we generally associate a swamp vegetation. They exist -on the plains, but only in favored, that is to say wet, spots. Larger -and more typical tracts grow farther north where the heavier rains of -the Amazon basin fall. - -The floods of the wet tropical season also have a restricting influence -upon the tropical forest. They deliver such vast quantities of water to -the low-gradient lowland streams that the plains rivers double, even -treble, their width and huge pools and even temporary lakes form in the -shallow depressions back of the natural levees. Of trees in the flooded -areas there are only those few species that can grow standing in water -several months each year. There are also cane and bamboo, ferns in -unlimited numbers, and a dense growth of jungle. These are the haunts of -the peccary, the red forest deer, and the jungle cat. Except along the -narrow and tortuous animal trails the country is quite impassable. Thus -for the sturdiest and most useful forest growth the one-wet-one-dry -season zone of the plains has alternately too much and too little water. -The rubber tree is most tolerant toward these conditions. Some of the -best stands of rubber trees in Amazonia are in the southwestern part of -the basin of eastern Peru and Bolivia, where there is the most typical -development of the habitat marked by the seasonal alternation of floods -and high temperatures. - -When tropical agriculture is extended to the plains the long dry season -will be found greatly to favor it. The southwestern quadrant of the -Amazon basin, above referred to, is the best agricultural area within -it. The northern limits of the tract are only a little beyond the Pongo. -Thence northward the climate becomes wetter. Indeed the best tracts of -all extend from Bolivia only a little way into southeastern Peru, and -are coincident with the patchy grasslands that are there interspersed -with belts of woodland and forest. Sugar-cane is favored by a climate -that permits rapid growth with a heavy rainfall and a dry season is -required for quality and for the harvest. Rice and a multitude of -vegetable crops are also well suited to this type of climate. Even corn -can be grown in large quantities. - -At the present time tropical agriculture is almost wholly confined to -the mountain valleys. The reasons are not wholly climatic, as the above -enumeration of the advantages of the plains suggests. The consuming -centers are on the plateau toward the west and limitation to mule pack -transport always makes distance in a rough country a very serious -problem. The valleys combine with the advantage of a short haul a -climate astonishingly like the one just described. In fact it is even -more extreme in its seasonal contrasts. The explanation is dependent -upon precisely the same principles we have hitherto employed. The front -range of the Andes and the course of the Urubamba run parallel for some -distance. Further, the front range is in many places somewhat higher -than the mountain spurs and knobs directly behind it. Even when these -relations are reversed the front range still acts as a barrier to the -rains for all the deep valleys behind it whose courses are not directly -toward the plains. Thus, one of the largest valleys in Peru, the -Urubamba, drops to 3,400 feet at Santa Ana and to 2,000 feet at -Rosalina, well within the eastern scarp of the Andes. The mountains -immediately about it are from 6,000 to 10,000 feet high. The result is a -deep semi-arid pocket with only a patchy forest (Fig. 54, p. 79).[25] In -places the degree of seclusion from the wind is so great that the scrub, -cacti, and irrigation remind one strongly of the desert on the border of -an oasis, only here the transition is toward forests instead of barren -wastes. The dense forest, or _montaña_, grows in the zone of clouds and -maximum precipitation between 4,000 and 10,000 feet. At the lower limit -it descends a thousand feet farther on shady slopes than it does on -sunny slopes. The continuous forest is so closely restricted to the -cloud belt that in Fig. 99 the two limits may be seen in one photograph. -All these sharply defined limits and contrasts are due to the fact that -the broad valley, discharging through a narrow and remote gorge, is -really to leeward of all the mountains around it. It is like a real -desert basin except in a lesser degree of exclusion from the rains. If -it were narrow and small the rains formed on the surrounding heights -would be carried over into it. Rain on the hills and sunshine in the -valley is actually the day-by-day weather of the dry season. In the wet -season the sky is overcast, the rains are general, though lighter in the -valley pocket, and plants there have then their season of most rapid -growth. The dry season brings plants to maturity and is the time of -harvest. Hence sugar and cacao plantations on a large scale, hence a -varied life in a restricted area, hence a distinct geographic province -unique in South America. - - -INTER-ANDEAN VALLEY CLIMATES - -Not all the deep Andean valleys lie on or near the eastern border. Some, -like the Apurimac and the Marañon, extend well into the interior of the -Cordillera. Besides these deep remote valleys with their distinct -climatic belts are basins, most of them with outlets to the sea--broad -structural depressions occurring in some cases along large and in others -along small drainage lines. The Cuzco basin at 11,000 feet and the -Abancay basin at 6,000 to 8,000 feet are typical. Both have abrupt -borders, narrow outlets, large bordering alluvial fans, and fertile -irrigable soil. Their difference of elevation occurs at a critical -level. Corn will ripen in the Cuzco basin, but cane will not. Barley, -wheat, and potatoes are the staple crops in the one; sugar-cane, -alfalfa, and fruit in the other. Since both are bordered by high -pastures and by mineralized rocks, the deeper Abancay basin is more -varied. If it were not so difficult to get its products to market by -reason of its inaccessibility, the Abancay basin would be the more -important. In both areas there is less rainfall on the basin floor than -on the surrounding hills and mountains, and irrigation is practised, but -the deeper drier basin is the more dependent upon it. Many small high -basins are only within the limits of potato cultivation. They also -receive proportionately more rain. Hence irrigation is unnecessary. -According as the various basins take in one or another of the different -product levels (Fig. 35) their life is meager and unimportant or rich -and interesting. - -The deep-valley type of climate has the basin factors more strongly -developed. Below the Canyon of Choqquequirau, a topographic feature -comparable with the Canyon of Torontoy, the Apurimac descends to 3,000 -feet, broadens to several miles, and has large alluvial fans built into -it. Its floor is really arid, with naked gravel and rock, cacti stands, -and gnarled shrubs as the chief elements of the landscape. Moreover the -lower part of the valley is the steeper. A former erosion level is -indicated in Fig. 125. When it was in existence the slopes were more -moderate than now and the valley broad and open. Thereupon came uplift -and the incision of the stream to its present level. As a result, a -steep canyon was cut in the floor of a mature valley. Hence the slopes -are in a relation unlike that of most of the slopes in our most familiar -landscapes. The gentle slopes are above, the steep below. The break -between the two, a topographic unconformity, may be distinctly traced. - -[Illustration: FIG. 96--Snow-capped mountain, Soiroccocha, north of -Arma, Cordillera Vilcapampa. The blue glacier ice descends almost to the -edge of a belt of extraordinary woodland growing just under the -snowline. The glacier is seen to overhang the valley and to have built -on the steep valley wall terminal moraines whose outer slopes are almost -precipitous.] - -[Illustration: FIG. 97--Shrubby vegetation mixed with grass at 14,000 -feet (4,270 m.) on the northern or sunny slopes of the Cordillera -Vilcapampa above Pampaconas, a thousand feet below the snowline. The -grass is remarkably profuse and supports the flocks and herds of a -pastoral population.] - -[Illustration: FIG. 98--Dense ground cover, typical trees, epiphytes, -and parasites of the tropical rain forest at 2,500-3,000 feet between -Pongo de Mainique and Rosalina.] - -[Illustration: FIG. 99--The Urubamba Valley below Santa Ana. On the dry -valley floor is a mixed growth of scattered trees, shrubs and grass, -with shrubs predominating. Higher up a more luxuriant ravine vegetation -appears. On the upper spurs true forest patches occupy the shady slopes. -Finally, in the zone of clouds at the top of the picture is a continuous -forest. See Fig. 17, for regional applications.] - -Combined with these topographic features are certain climatic features -of equal precision. Between 7,000 and 13,000 feet is a zone of clouds -oftentimes marked out as distinctly as the belt of fog on the Peruvian -coast.[26] Rarely does it extend across the valley. Generally it hangs -as a white belt on the opposite walls. When the up-valley winds of day -begin to blow it drifts up-valley, oftentimes to be dissolved as it -strikes the warmer slopes of the upper valley, just as its settling -under surface is constantly being dissolved in the warm dry air of the -valley floor. Where the precipitation is heaviest there is a belt of -woodland--dark, twisted trees, moss-draped, wet--a Druid forest. Below -and above the woodland are grassy slopes. At Incahuasi a spur runs out -and down until at last it terminates between two deep canyons. No -ordinary wells could be successful. The ground water must be a thousand -feet down, so a canal, a tiny thing only a few inches wide and deep, has -been cut away up to a woodland stream. Thence the water is carried down -by a contour-like course out of the woodland into the pasture, and so -down to the narrow part of the spur where there is pasture but no -springs or streams. - -Corn fields surround the few scattered habitations that have been built -just above the break or shoulder on the valley wall where the woodland -terminates, and there are fine grazing lands. The trails follow the -upper slopes whose gentler contours permit a certain liberty of -movement. Then the way plunges downward over a staircase trail, over -steep boulder-strewn slopes to the arid floor of a tributary where -nature has built a graded route. And so to the still more arid floor of -the main valley, where the ample and moderate slopes of the alluvial -fans with their mountain streams permit plantation agriculture again to -come in. - -To these three climates, the western border type, the eastern border -type, and the inter-Andean type, we have given chief attention because -they have the most important human relations. The statistical records of -the expedition as shown in the curves and the discussion that -accompanies them give attention to those climatic features that are of -theoretical rather than practical interest, and are largely concerned -with the conventional expression of the facts of weather and climate. -They are therefore combined in the following chapter which is devoted -chiefly to a technical discussion of the meteorology as distinguished -from the climatology of the Peruvian Andes. - - - - -CHAPTER X - -METEOROLOGICAL RECORDS FROM THE PERUVIAN ANDES - - -INTRODUCTION - -The data in this chapter, on the weather and climate of the Peruvian -Andes, were gathered under the usual difficulties that accompany the -collection of records at camps scarcely ever pitched at the same -elevation or with the same exposure two days in succession. Some of -them, and I may add, the best, were contributed by volunteer observers -at fixed stations. The observations are not confined to the field of the -Yale Peruvian Expedition of 1911, but include also observations from -Professor Hiram Bingham’s Expeditions of 1912 and 1914-15, together with -data from the Yale South American Expedition of 1907. In addition I have -used observations supplied by the Morococha Mining Company through J. P. -Little. Some hitherto unpublished observations from Cochabamba, Bolivia, -gathered by Herr Krüger at considerable expense of money for instruments -and of time from a large business, are also included, and he deserves -the more credit for his generous gift of these data since they were -collected for scientific purposes only and not in connection with -enterprises in which they might be of pecuniary value. My only excuse to -Herr Krüger for this long delay in publication (they were put into my -hands in 1907) is that I have wanted to publish his data in a dignified -form and also to use them for comparison with the data of other climatic -provinces. - -A further word to the reader seems necessary before he examines the -following curves and tables. It would be somewhat audacious to assume -that these short-term records have far-reaching importance. Much of -their value lies in their organization with respect to the data already -published on the climate of Peru. But since this would require a delay -of several years in their publication it seems better to present them -now in their simplest form. After all, the professional climatologist, -to whom they are chiefly of interest, scarcely needs to have such -organization supplied to him. Then, too, we hope that there will become -available in the next ten or fifteen years a vastly larger body of -climatological facts from this region. When these have been collected we -may look forward to a volume or a series of volumes on the “Climate of -Peru,†with full statistical tables and a complete discussion of them. -That would seem to be the best time for the reproduction of the detailed -statistics now on hand. It is only necessary that there shall be -sufficient analysis of the data from time to time to give a general idea -of their character and to indicate in what way the scope of the -observations might profitably be extended. I have, therefore, taken from -the available facts only such as seem to me of the most importance -because of their unusual character or their special relations to the -boundaries of plant provinces or of the so-called “natural regions†of -geography. - - -MACHU PICCHU[27] - -The following observations are of special interest in that they -illustrate the weather during the southern winter and spring at the -famous ruins of Machu Picchu in the Canyon of Torontoy. The elevation is -8,500 feet. The period they cover is too short to give more than a hint -of the climate or of the weather for the year. It extends from August -20, 1912, to November 6, 1912 (79 days). - - ANALYTICAL TABLE OF WIND DIRECTIONS, MACHU PICCHU, 1912 - - -----------+--------------------------------------------------------+ - | Number of Observations | - Direction +----------------------------+---------------------------| - of wind | Aug. 20 -- Sept. 30 | Oct. 1 -- Nov. 6 | - | 7 a. m. 1 p. m. 7 p. m. | 7 a. m. 1 p. m. 7 p. m. | - -----------+----------------------------+---------------------------+ - N. | 5 2 5 | 2 -- -- | - N.W. | 9 10 14 | 4 6 11 | - W. | -- 1 2 | 2 2 4 | - S. W. | -- -- 1 | 1 1 6 | - S. | -- -- 1 | -- -- 2 | - S. E. | 4 2 1 | -- -- 3 | - E. | 6 3 3 | 12 4 4 | - N. E. | 8 7 6 | 4 1 3 | - CALM | -- -- 2 | 5 3 3 | - -----------+----------------------------+---------------------------+ - - ----------------------------------------------------------------+ - | Percentages of Total Observation[28] | - Direction|------------------------------------------------------| - of wind | Aug. 20 ---- Sept. 30 | Oct. 1 ---- Nov. 6 | - | 7 a. m. 1 p.m. 7 p. m. | 7 a. m. 1 p. m. 7 p. m.| - ----------------------------------------------------------------| - N. | 15.6 8.0 14.2 | 6.7 ---- ---- | - N. W. | 28.1 40.0 40.0 | 13.3 35.3 30.7 | - W. | ---- 4.0 5.7 | 6.7 11.8 11.1 | - S. W. | ---- ---- 2.8 | 3.3 5.9 16.7 | - S. | ---- ---- 2.8 | ---- ---- 5.5 | - S. E. | 12.5 8.0 2.8 | ---- ---- 8.3 | - E. | 18.8 12.0 8.6 | 40.0 23.5 11.1 | - N. E. | 25.0 28.0 17.1 | 13.3 5.9 8.3 | - CALM | ---- ---- 5.7 | 16.7 17.6 8.3 | - ----------------------------------------------------------------+ - -[Illustration: FIG. 100--Wind roses for Machu Picchu, August 20 to -November 6, 1912.] - -The high percentage of northwest winds during afternoon hours is due to -the up-valley movement of the air common to almost all mountain borders. -The air over a mountain slope is heated more than the free air at the -same elevation over the plains (or lower valley); hence a barometric -gradient towards the mountain becomes established. At Machu Picchu the -Canyon of Torontoy trends northwest, making there a sharp turn from an -equally sharp northeast bend directly upstream. The easterly components -are unrelated to the topography. They represent the trades. If a wind -rose were made for still earlier morning hours these winds would be more -faithfully represented. That an easterly and northeasterly rather than a -southeasterly direction should be assumed by the trades is not difficult -to believe when we consider the trend of the Cordillera--southeast to -northwest. The observations from here down to the plains all show that -there is a distinct change in wind direction in sympathy with the larger -features of the topography, especially the deep valleys and canyons, the -trades coming in from the northeast. - - -CLOUDINESS - -It will be seen that the sky was overcast or a fog lay in the valley 53 -per cent of the time at early morning hours. Even at noon the sky was at -no time clear, and it was more than 50 per cent clear only 18 per cent -of the time. Yet this is the so-called “dry†season of the valleys of -the eastern Andes. The rainfall record is in close sympathy. In the 79 -days’ observations rain is recorded on 50 days with a greater proportion -from mid-September to the end of the period (November 6), a distinct -transition toward the wet period that extends from December to May. The -approximate distribution of the rains by hours of observation (7 A. M., -1 P. M., 7 P. M.) was in the ratio 4:3:6. Also the greatest number of -heavy showers as well as the greatest number of showers took place in -the evening. The rainfall was apparently unrelated to wind direction in -the immediate locality, though undoubtedly associated with the regional -movement of the moist plains air toward the mountains. All these facts -regarding clouds and rain plainly show the location of the place in the -belt of maximum precipitation. There is, therefore, a heavy cover of -vegetation. While the situation is admirable for defence, the murky -skies and frequent fogs somewhat offset its topographic surroundings as -a lookout. - - ANALYTICAL TABLE OF THE STATE OF THE SKY, MACHU PICCHU, 1912 - - ---------------+-------------+-------------+ - | Morning | Total | - ---------------+------+------+------+------+ - |Aug.- |Oct.- |Days | % | - |Sept. |Nov. | | | - ---------------+------+------+------+------+ - Foggy | 3.0 | 14.0 | 17.0 | 28.4 | - Overcast | 12.0 | 3.0 | 15.0 | 25.0 | - 50-100% cloudy | 4.0 | 10.0 | 14.0 | 23.3 | - 0-50% cloudy | 6.0 | 4.0 | 10.0 | 16.7 | - Clear | 3.0 | 1.0 | 4.0 | 6.6 | - ---------------+------+------+------+------+ - - ---------------+-------------+-------------+ - | Noon | Total | - ---------------+------+------+------+------+ - |Aug.- |Oct.- | Days | % | - |Sept. |Nov. | | | - ---------------+------+------+------+------+ - Foggy | 1.0 | -- | 1.0 | 2.6 | - Overcast | 6.0 | 8.0 | 14.0 | 36.8 | - 50-100% cloudy | 0.0 | 7.0 | 16.0 | 42.2 | - 0-50% cloudy | 5.0 | 2.0 | 7.0 | 18.4 | - Clear | 0.0 | 0.0 | 0.0 | 0.0 | - ---------------+------+------+------+------+ - - ---------------+-------------+------------- - | Evening | Total - ---------------+------+------+------+------ - |Aug.- |Oct.- |Days | % - |Sept. |Nov. | | - ---------------+------+------+------+------ - Foggy | 1.0 | 2.0 | 3.0 | 4.3 - Overcast | 13.0 | 11.0 | 24.0 | 34.8 - 50-100% cloudy | 8.0 | 15.0 | 23.0 | 33.3 - 0-50% cloudy | 9.0 | 4.0 | 13.0 | 18.8 - Clear | 3.0 | 3.0 | 6.0 | 8.8 - ---------------+------+------+------+------ - - -SANTA LUCIA[29] - -Santa Lucia is a mining center in the province of Puno (16° S.), at the -head of a valley here running northeast towards Lake Titicaca. Its -elevation, 15,500 feet above sea level, confers on it unusual interest -as a meteorological station. A thermograph has been installed which -enables a closer study of the temperature to be made than in the case of -the other stations. It is unfortunate, however, that the observations -upon clouds, wind directions, etc., should not have been taken at -regular hours. The time ranges from 8.30 to 11.30 for morning hours and -from 2.30 to 5.30 for afternoon. The observations cover portions of the -years 1913 and 1914. - - -TEMPERATURE - -Perhaps the most striking features of the weather of Santa Lucia are the -highly regular changes of temperature from night to day or the uniformly -great diurnal range and the small differences of temperature from day to -day or the low diurnal variability. For the whole period of nearly a -year the diurnal variability never exceeds 9.5° F. (5.3° C.) and for -days at a time it does not exceed 2-3° F. (1.1°-1.7° C.). The most -frequent variation, occurring on 71 per cent of the total number of -days, is from 0-3° F., and the mean for the year gives the low -variability of 1.9° F. (1.06° C.). These facts, illustrative of a type -of weather comparable in _uniformity_ with low stations on the Amazon -plains, are shown in the table following as well as in the accompanying -curves. - - FREQUENCY OF THE DIURNAL VARIABILITY, SANTA LUCIA, 1913-14 - - ----------+----+----+----+----+-----+ - | | | | | | - Degrees F.|May |June|July|Aug.|Sept.| - ----------+----+----+----+----+-----+ - 0 | -- | 2 | 6 | 3 | 4 | - 0-1 | 2 | 7 | 7 | 5 | 6 | - 1-2 | 11 | 5 | 7 | 11 | 7 | - 2-3 | 2 | 8 | 8 | 9 | 3 | - 3-4 | 4 | 4 | 2 | 1 | 4 | - 4-5 | 1 | 3 | 1 | -- | 2 | - Over 5 | -- | 1 | -- | 2 | 4 | - ----------+----+----+----+----+-----+ - Days per| 20 | 30 | 31 | 31 | 30 | - month| | | | | | - ----------+----+----+----+----+-----+ - - ----------+----+----+----+----+----+-----++--------- - | | | | | | ||Total No. - Degrees F.|Oct.|Nov.|Dec.|Jan.|Feb.|March||of days - ----------+----+----+----+----+----+-----++--------- - 0 | 6 | 2 | -- | 1 | -- | 2 || 26 - 0-1 | 4 | 8 | 12 | 14 | 9 | 5 || 79 - 1-2 | 8 | 5 | 5 | 4 | 9 | 13 || 85 - 2-3 | 7 | 7 | 5 | 5 | 4 | 6 || 64 - 3-4 | 1 | 3 | 6 | 2 | 4 | 2 || 33 - 4-5 | 1 | 3 | -- | 2 | 1 | 1 || 15 - Over 5 | 4 | 2 | 2 | 3 | 1 | -- || 19 - ----------+----+----+----+----+----+-----++--------- - Days per| 31 | 30 | 30 | 31 | 28 | 29 || 321 - month| | | | | | || - ----------+----+----+----+----+----+-----++--------- - -If we take the means of the diurnal variations by months we have a still -more striking curve showing how little change there is between -successive days. June and December are marked by humps in the curve. -They are the months of extreme weather when for several weeks the -temperatures drop to their lowest or climb to their highest levels. -Moreover, there is at these lofty stations no pronounced lag of the -maximum and minimum temperatures for the year behind the times of -greatest and least heating such as we have at lower levels in the -temperate zone. Thus we have the highest temperature for the year on -December 2, 70.4° F. (21.3° C.), the lowest on June 3, 0.2° F. (--17.7° -C.). The daily maxima and minima have the same characteristic. Radiation -is active in the thin air of high stations and there is a very direct -relation between the times of greatest heat received and greatest heat -contained. The process is seen at its best immediately after the sun is -obscured by clouds. In five minutes I have observed the temperature drop -20° F. (11.1° C.) at 16,000 feet (4,877 m.); and a drop of 10° F. (5.6° -C.) is common anywhere above 14,000 feet (4,267 m.). In the curves of -daily maximum and minimum temperatures we have clearly brought out the -uniformity with which the maxima of high-level stations rise to a mean -level during the winter months (May-August). Only at long intervals is -there a short series of cloudy days when the maximum is 10°-12° F. -(5.6°-6.7° C.) below the normal and the minimum stands at abnormally -high levels. Since clouds form at night in quite variable amounts--in -contrast to the nearly cloudless days--there is a far greater -variability among the minimum temperatures. Indeed the variability of -the winter minima is greater than that of the summer minima, for at the -latter season the nightly cloud cover imposes much more stable -atmospheric temperatures. The summer maxima have a greater degree of -variability. Several clear days in succession allow the temperature to -rise from 5°-10° F. (2.8°-5.6° C.) above the winter maxima. But such -extremes are rather strictly confined to the height of the summer -season--December and January. For the rest of the summer the maxima rise -only a few degrees above those of the winter. This feature of the -climate combines with a December maximum of rainfall to limit the period -of most rapid plant growth to two months. Barley sown in late November -could scarcely mature by the end of January, even if growing on the -Argentine plains and much less at an elevation which carries the night -temperatures below freezing at least once a week and where the mean -temperature hovers about 47° F. (8.3° C.). The proper conditions for -barley growing are not encountered above 13,000 to 13,500 feet and the -farmer cannot be certain that it will ripen above 12,500 feet in the -latitude of Santa Lucia. - -The curve of mean monthly temperatures expresses a fact of great -importance in the plant growth at high situations in the Andes--the -sharp break between the winter and summer seasons. There are no real -spring and autumn seasons. This is especially well shown in the curve -for non-periodic mean monthly range of temperature for the month of -October. During the half of the year that the sun is in the southern -hemisphere the sun’s noonday rays strike Santa Lucia at an angle that -varies between 0° and 16° from the vertical. The days and nights are of -almost equal length and though there is rapid radiation at night there -is also rapid insolation by day. When the sun is in the northern -hemisphere the days are shortened from one to two hours and the angle of -insolation decreased, whence the total amount of heat received is so -diminished that the mean monthly temperature lies only a little above -freezing point. In winter the quiet pools beside the springs freeze over -long before dark as the hill shadows grow down into the high-level -valleys, and by morning ice also covers the brooks and marshes. Yet the -sun and wind-cured _ichu_ grass lives here, pale green in summer, -straw-yellow in winter. The tola bush also grows rather abundantly. But -we are almost at the upper limit of the finer grasses and a few hundred -feet higher carries one into the realm of the snowline vegetation, -mosses and lichens and a few sturdy flowering plants. - -For convenience in future comparative studies the absolute extremes are -arranged in the following table: - -[Illustration: FIG. 101 A--DIURNAL TEMPERATURE, SANTA LUCIA, 1913-’14 -C--DIURNAL RANGE OF TEMPERATURE, SANTA LUCIA, 1913-’14 E--DIURNAL -VARIABILITY OF TEMPERATURE, SANTA LUCIA, 1913-’14 B--MEAN MONTHLY -TEMPERATURE, SANTA LUCIA, 1913-’14 D--MONTHLY MEANS OF DIURNAL RANGE OF -TEMPERATURE, SANTA LUCIA, 1913-’14 F--RELATIVE HUMIDITY, SANTA LUCIA, -1913-’14] - - ABSOLUTE MONTHLY EXTREMES, SANTA LUCIA, 1913-14 - - -----------------------+----------++----------+---------------- - Date | Highest || Lowest | Date - -----------------------+----------++----------+---------------- - May[30] (12) | 62° F. || 9° F. | May (25, 26) - June (4 days) | 60° F. || 0.2° F. | June (3) - July (4 days, 31) | 60° F. || 5° F. | July (8) - Aug. (8, 26) | 62° F. || 4° F. | Aug. (4, 5) - Sept. (several days) | 62° F. || 7° F. | Sept. (4 days) - Oct. (24) | 63° F. || 10° F. | Oct. (12, 13) - Nov. (11)[31] | 63° F. || 24.0° F. | Nov. (29) - Dec. (2) | 70.4° F. || 22.2° F. | Dec. (14) - Jan. (19) | 69.5° F. || 26.5° F. | Jan. (3, 15) - Feb. (16, 18) | 63.2° F. || 30.5° F. | Feb. (23) - March (8) | 68.4° F. || 28.5° F. | March (6) - -----------------------+----------++----------+---------------- - - -RAINFALL - -The rainfall record for Santa Lucia is for the year beginning November, -1913. For this period the precipitation amounts to 24.9 inches of which -over 85 per cent fell in the rainy season from November to March. Most -of the rain fell during the violent afternoon tempests that characterize -the summer of these high altitudes. - -The rainfall of Santa Lucia for this first year of record approximates -closely to the yearly mean of 23.8 inches for the station of Caylloma in -the adjacent province of that name. Caylloma is the center of a mining -district essentially similar to Santa Lucia though the elevation of its -meteorological station, 14,196 feet (4,330 m.), is lower. It is one of -the few Peruvian stations for which a comparatively long series of -records is available. The _BoletÃn de la Sociedad Geográfica de -Lima_[32] contains a résumé of rainfall and temperature for seven years, -1896-7 to 1902-3. Later data may be found in subsequent volumes of the -same publication but they have not been summarized or in any way -prepared for analysis and they contain several typographical errors. A -graphic representation of the monthly rainfall for the earlier period is -here reproduced from the _BoletÃn de minas del Perú_.[33] The amount -of precipitation fluctuates considerably from year to year. For the -earlier period, with a mean of 23.8 inches the minimum (1896-7) was 8 -inches and the maximum (1898-9) 36 inches. For the later period, 1903-4 -to 1910-11, with a mean of 29.5 inches the minimum (1904-5) was 17.5 -inches and the maximum (1906-7) was 43 inches. - -[Illustration: FIG. 102--Monthly rainfall of Santa Lucia for the year -November, 1913, to October, 1914. No rain fell in July and August.] - -[Illustration: FIG. 103A--Maximum, mean and minimum monthly rainfall of -Caylloma for the period 1896-7 to 1902-3. July was absolutely rainless. -Caylloma is situated immediately east of the crest of the Maritime -Cordillera in a position similar to that of Santa Lucia (see Fig. 66).] - -[Illustration: FIG. 103B--Annual rainfall of Caylloma for the periods -1896-7 to 1902-3; 1903-4 to 1910-11 and for 1915-6 (incomplete: May and -June, months of low rainfall, are missing). Means for the respective -seven and eight year periods are shown and the rainfall of Santa Lucia -for the single observation year is inserted for comparison.] - - RAINFALL, SANTA LUCIA, NOV. 1913 TO OCT. 1914 - - ---------+---------+----------+----------+--------------- - |No of |No. of |Max. for |Total rainfall - |fine days|rainy days|single day|in inches - ---------+---------+----------+----------+--------------- - November | 9 | 21 | 1.150 | 4.264[34] - December | 16 | 15 | .700 | 6.439 - January | 17 | 14 | .610 | 3.313 - February | 9 | 17 | .910 | 2.975 - March | 11 | 20 | 1.102 | 4.381 - April | 17 | 13 | 0.31 | 0.92 - May | 8 | 23 | 0.35 | 1.63 - June | 27 | 3 | 0.05 | 0.07 - July | 31 | 0 | 0.00 | 0.00 - August | 31 | 0 | 0.00 | 0.00 - September| 23 | 7 | 0.05 | 0.35 - October | 21 | 10 | 0.14 | 0.56 - ---------+---------+----------+----------+--------------- - Total | | | | 24.902 - ---------+---------+----------+----------+--------------- - - -WIND - -An analysis of the wind at Santa Lucia shows an excess of north and -south winds over those of all other directions. The wind-rose for the -entire period of observation (Fig. 104) clearly expresses this fact. -When this element is removed we observe a strongly seasonal distribution -of the wind. The winter is the time of north and south winds. In summer -the winds are chiefly from the northeast or the southwest. Among single -months, August and February show this fact clearly as well as the less -decisive character of the summer (February) wind. - -The mean wind velocity for the month of February was 540 meters per -minute for the morning and 470 meters per minute for the afternoon. The -higher morning rate, an unusual feature of the weather of high -stations, or indeed of wind-phenomena in general, is due, however, to -exceptional changes in wind strength on two days of the month, the 16th -and 25th, when the velocity decreased from a little less than a thousand -meters per minute in the morning to 4 and 152 meters respectively in the -afternoon. More typical is the March record for 1914 at Santa Lucia, -when the wind was _always_ stronger in the afternoon than in the -morning, their ratios being 550 to 510. - -[Illustration: Fig. 104--Monthly wind roses for Santa Lucia, June, 1913, -to July, 1914, and composite rose for the whole period of observation.] - - -CLOUD - -The greater strength of the afternoon wind would lead us to suppose that -the cloudiness, which in the trade-wind belt, is to so great an extent -dependent on the wind, is greatest in the afternoon. The diagrams bring -out this fact. Barely is the sky quite clear after the noon hour. Still -more striking is the contrast between the morning and afternoon if we -combine the two densest shadings of the figures. Light, high-lying -cirrus clouds are most characteristic of early morning hours. They -produce some very striking sky effects just before sunrise as they catch -the sun’s rays aloft. An hour or two after sunrise they disappear and -small cumulus clouds begin to form. These grow rapidly as the winds -begin and by afternoon become bulky and numerous. In the wet season they -grow into the nimbus and stratus types that precede a sudden downpour of -water or a furious hailstorm. This is best seen from the base of a -mountain range looking towards the crest, where the cloud-and -rain-making processes of this type are most active. - - CLOUD ANALYSIS, SANTA LUCIA - - --------------+---------+---------+---------+---------+---------++---------+ - | Nov. | Dec. | Jan. | Feb. | March || Total | - Type of cloud |a.m. p.m.|a.m. p.m.|a.m. p.m.|a.m. p.m.|a.m. p.m.||a.m. p.m.| - --------------+---------+---------+---------+---------+---------++---------+ - Cirrus | 6 2 | 15 2 | 9 2 | 5 3 | 6 3 || 41 12 | - Cirro-stratus | -- -- | -- -- | -- -- | -- -- | -- -- || -- -- | - Cirro-cumulus | 4 4 | 7 11 | 3 5 | 6 8 | 17 10 || 37 38 | - Cumulus | 3 4 | 4 7 | 10 9 | 15 13 | 5 13 || 37 46 | - Strato-cumulus| 2 6 | 3 10 | 7 14 | 2 3 | -- 3 || 14 36 | - Stratus | -- -- | -- 1 | -- -- | -- 1 | 1 2 || 2 4 | - Nimbus | -- -- | -- -- | -- -- | -- -- | -- -- || -- -- | - Clear | -- -- | 2 -- | 2 1 | -- -- | 2 -- || 6 1 | - --------------+---------+---------+---------+---------+---------++---------+ - - -UNUSUAL WEATHER PHENOMENA, SANTA LUCIA, 1913-14 - -[Illustration: Fig. 105--Monthly cloudiness of Santa Lucia from January -to July, 1914. Mean cloudiness for the whole period is also shown.] - -The following abstracts are selected because they give some important -features of the weather not included in the preceding tables and graphs. -Of special interest are the strong contrasts between the comparatively -high temperatures of midday and the sudden “tempests†accompanied by -rain or hail that follow the strong convectional movements dependent -upon rapid and unequal heating. The furious winds drive the particles of -hail like shot. It is sometimes impossible to face them and the pack -train must be halted until the storm has passed. Frequently they leave -the ground white with hailstones. We encountered one after another of -these “tempestades†on the divide between Lambrama and Antabamba in -1911. They are among the most impetuous little storms I have ever -experienced. The longest of them raged on the divide from two-o’clock -until dark, though in the valleys the sun was shining. Fortunately, in -this latitude they do not turn into heavy snowstorms as in the -Cordillera of northwestern Argentina, where the passes are now and then -blocked for weeks at a time and loss of human life is no infrequent -occurrence.[35] They do, however, drive the shepherds down from the -highest slopes to the mid-valley pastures and make travel uncomfortable -if not unsafe. - -ABSTRACT FROM DAILY WEATHER OBSERVATIONS, SANTA LUCIA, 1913-14 - - NOVEMBER - - “Tempest†recorded 11 times, distant thunder and lightning 9 times. - Unusual weather records: “clear sky, scorching sun, good weather†- (Nov. 29); “morning sky without a single cloud, weather agreeable†- (Nov. 30). - - DECEMBER - - Clear morning sky 6 times. Starry night or part of night 7 times. - Beginning of rain and strong wind frequently observed at 5-6 P.M. - “Tempest†mentioned 19 times--5 times at midnight, 8 times at 5-6 - P.M. - - JANUARY - - Clear morning sky 5 times. Starry night 3 times. Rain, actual or - threatening, characteristic of afternoons. “Tempest,†generally - about 5-6 P.M., 7 times. Sun described 4 times as scorching and, - when without wind, heat as stifling. Weather once “agreeable.†- - FEBRUARY - - Constant cloud changes, frequent afternoon or evening rains. - “Tempest,†generally 4 P.M. and later, 16 times. - - MARCH - - Twice clear morning skies, once starry night. Scorching sun and - stifling heat on one occasion. “Tempest,†generally in late - afternoon and accompanied by hail, 19 times. Observed 3 or 4 times - a strong, “land breeze†(terral) of short duration (15-20 mins.) - and at midnight. - - -MOROCOCHA - -Morococha, in the Department of Ancachs, Peru, lies in 76° 11′ west -longitude and 11° 45′ south latitude and immediately east of the crest -line of the Maritime Cordillera. It is 14,300 feet above sea level, and -is surrounded by mountains that extend from 1,000 to 3,000 feet higher. -The weather records are of special interest in comparison with those of -Santa Lucia. Topographically the situations of the two stations are -closely similar hence we may look for climatic differences dependent on -the latitudinal difference. This is shown in the heavier rainfall of -Morococha, 4° nearer the equatorial climatic zone. (For location see -Fig. 66.) - -The meteorological data for 1908-09 were obtained from records kept by -the Morococha Mining Company for use in a projected hydro-electric -installation. Other data covering the years 1906-11 have appeared in the -bulletins of the _Sociedad Geográfica de Lima_. These are not complete -but they have supplied rainfall data for the years 1910-11;[36] those -for 1906 and 1907 have been obtained from the _BoletÃn de Minas_.[37] - - -TEMPERATURE - -The most striking facts expressed by the various temperature curves are -the shortness of the true winter season--its restriction to June and -July--and its abrupt beginning and end. This is well known to anyone who -has lived from April to October or November at high elevations in the -Central Andes. Winter comes on suddenly and with surprising regularity -from year to year during the last few days of May and early June. In the -last week of July or the first week of August the temperatures make an -equally sudden rise. During 1908 and 1909 the mean temperature reached -the freezing point but once each year--July 24 and July 12 -respectively. The absolute minimum for the two years was -22° C. July of -1908 and June of 1909 are also the months of smallest diurnal -variability, showing that the winter temperatures are maintained with -great regularity. Like all tropical high-level stations, Morococha -exhibits winter maxima that are very high as compared with the winter -maxima of the temperate zone. In both June and July of 1908 and 1909 the -maximum was maintained for about a week above 55° F. (12.8° C.), and in -1909 above 60° F. (15.6° C.), the mean maximum for the year being only -4.7° F. higher. For equal periods, however, the maxima fell to levels -about 10° F. below those for the period from December to May, 1908. - -It is noteworthy that the lowest maximum for 1909 was in October, 44° F. -(6.7° C.); and that other low maxima but little above those of June and -July occur in almost all the other months of the year. While 1909 was in -this respect an exceptional year, it nevertheless illustrates a fact -that may occur in any month of any year. Its occurrence is generally -associated with cloudiness. One of the best examples of this is found in -the January maximum curve for 1909, where in a few days the maxima fell -12° F. Cloud records are absent, hence a direct comparison cannot be -made, but a comparison of the maximum temperature curve with the graphic -representation of mean monthly rainfall, will emphasize this relation of -temperature and cloudiness. February was the wettest month of both 1908 -and 1909. In sympathy with this is the large and sharp drop from the -January level of the maxima--the highest for the year--to the February -level. The mean temperatures are affected to a less degree because the -cloudiness retards night radiation of heat, thus elevating the maxima. -Thus in 1908 the lowest minimum for both January and February was 28.4° -F. (-2° C.). For 1909 the minima for January and February were 27.5° F. -(-2.5° C.) and 29.3° F. (-1.5° C.) respectively. - -[Illustration: FIG. 106 A--DIURNAL TEMPERATURE, MOROCOCHA, 1908 - -B--DIURNAL TEMPERATURE, MOROCOCHA, 1909 - -D--DIURNAL RANGE OF TEMPERATURE, MOROCOCHA, 1908 - -E--DIURNAL RANGE OF TEMPERATURE, MOROCOCHA, 1909 - -G--DIURNAL VARIABILITY OF TEMPERATURE, MOROCOCHA, 1908 - -H--DIURNAL VARIABILITY OF TEMPERATURE, MOROCOCHA, 1909 - -C--MEAN MONTHLY TEMPERATURE, MOROCOCHA - -F--MONTHLY MEANS OF DIURNAL RANGE OF TEMPERATURE, MOROCOCHA] - -The extent to which high minima may hold up the mean temperature is -shown by the fact that the mean monthly temperature for January, 1908, -was lower than for February. Single instances illustrate this relation -equally well. For example, on March 5th, 1908, there occurred the -heaviest rainfall of that year. The maximum and minimum curves almost -touch. The middle of April and late September, 1909, are other -illustrations. The relationship is so striking that I have put the two -curves side by side and have had them drawn to the same scale. - - FREQUENCY OF THE DIURNAL VARIABILITY, MOROCOCHA, 1908 AND 1909 - - 1908 - ----------------------------------------------------------------- - Degrees | | | | | | | | | | | | |Total No. - F. | J.| F.| M.| A.| M.| J.| J.| A.| S.| O.| N.| D.| of days - --------+---+---+---+---+---+---+---+---+---+---+---+---+--------- - 0 | --| 3 | 2 | 3 | --| --| 2 | 1 | 3 | 1 | 1 | 3 | 19 - 0-1 | 6 | 5 | 6 |10 | 9 |10 |13 |10 | 8 | 6 | 6 | 5 | 94 - 1-2 | 4 | 1 | 3 | 7 | 5 | 3 | 7 | 7 | 8 | 6 | 6 | 4 | 61 - 2-3 | 6 | 1 | 3 | 4 | 9 | 2 | 2 | 4 | 4 | 7 | 7 | 4 | 53 - 3-4 | 5 | 3 | 2 | 3 | 3 | 4 | 2 | 9 | 4 | 5 | 3 | 5 | 48 - 4-5 | 2 | 3 | 1 | 1 | 2 | 5 | 5 | --| 1 | 1 | 6 | 3 | 30 - Over 5 | 3 | 4 | 3 | 2 | 3 | 6 | --| --| 2 | 5 | 1 | 5 | 34 - --------+---+---+---+---+---+---+---+---+---+---+---+---+--------- - Days per|26 |20 |20 |30 |31 |30 |31 |31 |30 |31 |30 |20 | 339 - month | | | | | | | | | | | | | - ------------------------------------------------------------------ - 1909 - --------------------------------------------------------------------- - | | | | | | | | | | | | | |Mean - Degrees | | | | | | | | | | | | |Total |for - F. | J.| F.| M.| A.| M.| J.| J.| A.| S.| O.| N.| D.|No. of|1908 - | | | | | | | | | | | | | days |-1909 - --------+---+---+---+---+---+---+---+---+---+---+---+---+------+----- - 0 | 6 | 1 | 4 | 2 | 1 | 2 | 4 | 4 | 3 | 6 | 2 | 1 | 36 | 27.5 - 0-1 | 9 | 8 | 5 | 6 | 6 | 7 | 8 |13 | 9 | 4 |11 |10 | 96 | 95 - 1-2 | 4 | 6 | 8 | 3 |11 |14 | 3 | 3 | 5 | 3 | 9 | 6 | 75 | 68 - 2-3 | 3 | 7 | 4 | 8 | 4 | 3 | 6 | 6 | 4 | 6 | 1 | 3 | 55 | 54 - 3-4 | 4 | 5 | 3 | 6 | 4 | 4 | 4 | 3 | 6 | 3 | 2 | 5 | 49 | 48.5 - 4-5 | 1 | 1 | 5 | 1 | 2 | --| 2 | 1 | 1 | 2 | --| 2 | 18 | 24 - Over 5 | 4 | --| 2 | 4 | 3 | --| 4 | 1 | 2 | 7 | 5 | 3 | 35 | 34.5 - --------+---+---+---+---+---+---+---+---+---+---+---+---+------+----- - Days per|31 |28 |31 |30 |31 |30 |31 |31 |30 |31 |30 |30 | 364 |351.5 - month | | | | | | | | | | | | | | - --------------------------------------------------------------------- - - -RAINFALL - -The annual rainfall of Morococha is as follows: - - 1906 28 inches ( 712 mm.) - 1907 40 " (1,011 mm.)[38] - 1908 57 " (1,450 mm.) - 1909 45 " (1,156 mm.) - 1910 47 " (1,195 mm.) - 1911 25 " ( 622 mm.) - -[Illustration: FIG. 107A.] - -[Illustration: FIG. 107B.] - -[Illustration: FIG. 107C.] - -[Illustration: Fig. 107--Rainfall of Morococha. Fig. 107A shows daily -rainfall during the rainy (summer) season, 1908-1909. Fig. 107B shows -monthly rainfall from July, 1905, to December, 1911, and Fig. 107C the -annual and mean rainfall for the same period.] - -The mean for the above six years amounts to 40 inches (1,024 mm.). This -is a value considerably higher than that for Caylloma or Santa Lucia. -The greater rainfall of Morococha is probably due in part to its more -northerly situation. An abnormal feature of the rainfall of 1908, the -rainiest year, is the large amount that fell in June. Ordinarily June -and July, the coldest months, are nearly or quite rainless. The normal -concurrence of highest temperatures and greatest precipitation is of -course highly favorable to the plant life of these great altitudes. Full -advantage can be taken of the low summer temperatures if the growing -temperatures are concentrated and are accompanied by abundant rains. -Since low temperatures mean physiologic dryness, whether or not rains -are abundant, the dryness of the winter months has little effect in -restricting the range of Alpine species. - -The seasonal distribution of rain helps the plateau people as well as -the plateau plants. The transportation methods are primitive and the -trails mere tracks that follow the natural lines of topography and -drainage. Coca is widely distributed, likewise corn and barley which -grow at higher elevations, and wool must be carried down to the markets -from high-level pastures. In the season of rains the trails are -excessively wet and slippery, the streams are often in flood and the -rains frequent and prolonged. On the other hand the insignificant -showers of the dry or non-growing season permit the various products to -be exchanged over dry trails. - -The activities of the plateau people have had a seasonal expression from -early times. Inca chronology counted the beginning of the year from the -middle of May, that is when the dry season was well started and it was -inaugurated with the festivals of the Sun. With the exception of June -when the people were entirely busied in the irrigation of their fields, -each month had its appropriate feasts until January, during which month -and February and March no feasts were held. April, the harvest month, -marked the recommencement of ceremonial observances and a revival of -social life.[39] - -In Spanish times the ritualistic festivals, incorporated with fairs, -followed the seasonal movement. Today progress in transportation has -caused the decadence of many of the fairs but others still survive. Thus -two of the most famous fairs of the last century, those of Vilque -(province of Puno) and Yunguyo (province of Chucuito), were held at the -end of May and the middle of August respectively. Copacavana, the famous -shrine on the shores of Titicaca, still has a well-attended August fair -and Huari, in the heart of the Bolivian plateau, has an Easter fair -celebrated throughout the Andes. - - -COCHABAMBA - -Cochabamba, Bolivia, lies 8,000 feet above sea level in a broad basin in -the Eastern Andes. The Cerro de Tunari, on the northwest, has a snow and -ice cover for part of the year. The tropical forests lie only a single -long day’s journey to the northeast. Yet the basin is dry on account of -an eastern front range that keeps out the rain-bearing trade winds. The -Rio Grande has here cut a deep valley by a roundabout course from the -mountains to the plains so that access to the region is over bordering -elevations. The basin is chiefly of structural origin. - -The weather records from Cochabamba are very important. I could obtain -none but temperature data and they are complete for 1906 only. Data for -1882-85 were secured by von Boeck[40] and they have been quoted by -Sievers and Hann. The mean annual temperature for 1906 was 61.9° F. -(16.6° C.), a figure in close agreement with von Boeck’s mean of 60.8° -F. (16° C.). The monthly means indicate a level of temperature favorable -to agriculture. The basin is in fact the most fertile and highly -cultivated area of its kind in Bolivia. Bananas, as well as many other -tropical and subtropical plants, grow in the central plaza. The nights -of midwinter are uncomfortably cool; and the days of midsummer are -uncomfortably hot but otherwise the temperatures are delightful. The -absolute extremes for 1906 were 81.5° F. (27.5° C.) on December 11, and -39.9° F. (4.4° C.) on July 15 and 16. The (uncorrected) readings of von -Boeck give a greater range. High minima rather than high maxima -characterize the summer. The curve for 1906 shows the maxima for June -and July cut off strikingly by an abrupt drop of the temperature and -indicates a rather close restriction of the depth of the season to these -two months, which are also those of greatest diurnal range. - -[Illustration: FIG. 108 A--DIURNAL TEMPERATURE, COCHABAMBA, 1906 - -B--DIURNAL TEMPERATURE, COCHABARMBA, 1907 - -E--DIURNAL RANGE OF TEMPERATURE, COCHABARMBA, 1907 - -D--DIURNAL RANGE OF TEMPERATURE, COCHABARMBA, 1906 - -G--DIURNAL VARIABILITY, COCHABARMBA, 1906 - -H--DIURNAL VARIABILITY, COCHABAMBA, 1907 - -C--MEAN MONTHLY TEMPERATURES, COCHABAMBA - -F--MONTHLY MEANS OF DIURNAL RANGE, COCHABAMBA] - -The rainfall of about 18 inches is concentrated in the summer season, 85 -per cent falling between November and March. During this time the town -is somewhat isolated by swollen streams and washed out trails: hence -here, as on the plateau, there is a distinct seasonal distribution of -the work of planting, harvesting, moving goods, and even mining, and of -the general commerce of the towns. There is an approach to our winter -season in this respect and in respect of a respite from the almost -continuously high temperatures of summer. The daytime temperatures of -summer are however mitigated by the drainage of cool air from the -surrounding highlands. This, indeed, prolongs the period required for -the maturing of plants, but there are no harmful results because -freezing temperatures are not reached, even in winter. - - MONTHLY TEMPERATURES, COCHABAMBA, 1906 - - -------------+-------------+-------------+-------------+-------------- - Month | Mean Min. | Mean Max. | Mean Range | Daily Mean - -------------+-------------+-------------+-------------+-------------- - January | 55.7 | 72.25 | 16.65 | 63.3 - February | 61.2 | 71.3 | 10.1 | 65.5 - March | 59.8 | 72.6 | 12.8 | 65.5 - April | 55.06 | 70.8 | 15.74 | 62.2 - May | 50.9 | 68.7 | 17.8 | 59.1 - June | 47.1 | 65.6 | 18.5 | 55.6 - July | 44.8 | 64.9 | 20.1 | 54.1 - August | 49.9 | 68.0 | 18.1 | 58.2 - September | 55.6 | 73.2 | 17.6 | 63.7 - October | 56.1 | 73.4 | 17.3 | 64.0 - November | 58.1 | 75.7 | 17.6 | 66.2 - December | 58.6 | 73.9 | 15.3 | 65.8 - -------------+-------------+-------------+-------------+-------------- - -[Illustration: FIGS. 109-113--Temperature curves for locations in the -montaña, July and August, 1911. The curves are based on hourly readings -with interpolated readings for such critical occurrences as the -appearance of cloud or rain. Dry bulb readings are shown by solid lines, -wet bulb by dotted lines, and breaks in the continuity of the -observations by heavy broken lines. Fig. 109 is for Pongo de Mainique, -August 20 and 21; Fig. 110 for Yavero; Fig. 111 for Santo Anato, August -11 and 12; Fig. 112 for Sahuayaco, August 20, and Fig. 113 for Santa -Ana, July 30 to August 1.] - -[Illustration: FIG. 114--Typical afternoon cloud composition at Santa -Ana during the dry season.] - -[Illustration: FIG. 115--Temperature curve for Abancay drawn from data -obtained by hourly readings on September 27, 1911. Dry bulb readings are -shown by a heavy solid line, wet bulb readings by a dotted line. The -heavy broken line shows the normal curve when the sky is unobscured by -cloud. The reduction in temperature with cloud is very marked.] - - FREQUENCY OF DIURNAL VARIABILITY AT COCHABAMBA, 1906 - - -------+----+----+----+----+----+----+----+----+----+----+----+----++------ - | | | | | | | | | | | | ||Total - Degrees| | | | | | | | | | | | ||No. of - F. | J. | F. | M. | A. | M. | J. | J. | A. | S. | O. | N. | D. || days - -------+----+----+----+----+----+----+----+----+----+----+----+----++------ - 0 | 1 | 3 | 10 | 12 | 6 | 10 | 9 | 6 | 9 | 6 | 3 | 4 || 79 - 0-1 | 5 | -- | 3 | 5 | 3 | 3 | -- | 4 | -- | 3 | 1 | 1 || 28 - 1-2 | 10 | 10 | 13 | 11 | 15 | 7 | 14 | 11 | 15 | 10 | 14 | 13 || 143 - 2-3 | 7 | 11 | 3 | 1 | 5 | 8 | 7 | 4 | 3 | 6 | 7 | 6 || 68 - 3-4 | 6 | 2 | 2 | 1 | 2 | 2 | 1 | 6 | 3 | 4 | 3 | 5 || 37 - 4-5 | -- | -- | -- | -- | -- | -- | -- | -- | -- | 1 | 1 | 1 || 3 - Over 5 | 2 | 2 | -- | -- | -- | -- | -- | -- | -- | 1 | 1 | 1 || 7 - -------+----+----+----+----+----+----+----+----+----+----+----+----++------ - -A series of curves shows the daily march of temperature at various -locations along the seventy-third meridian. Figs. 109 to 113 are for the -Urubamba Valley. Respectively they relate to Pongo de Mainique, 1,200 -feet elevation (365 m.), the gateway to the eastern plains; Yavero, -1,600 feet (488 m.), where the tributary of this name enters the main -stream; Santo Anato, 1,900 feet (580 m.); Sahuayaco, 2,400 feet (731 -m.), and Santa Ana, 3,400 feet (1,036 m.), one of the outposts of -civilization beyond the Eastern Cordillera. The meteorological -conditions shown are all on the same order. They are typical of dry -season weather on the dry floor of a montaña valley. The smooth curves -of clear days are marked by high mid-day temperatures and great diurnal -range. Santo Anato is a particularly good illustration: the range for -the 24 hours is 38° F. (21.1° C.). This site, too, is remarkable as one -of the most unhealthful of the entire valley. The walls of the valley -here make a sharp turn and free ventilation of the valley is obstructed. -During the wet season tertian fever prevails to a degree little known -east of the Cordillera, though notorious enough in the deep valleys of -the plateau. The curves show relative humidity falling to a very low -minimum on clear days. At Santo Anato and Santa Ana, for example, it -drops below 30 per cent during the heat of the day. Afternoon -cloudiness, however, is a common feature even of the dry season. A -typical afternoon cloud formation is shown in Fig. 114. The effect on -temperature is most marked. It is well shown in the curve for August 20 -and 22 at Yavero. Cloudiness and precipitation increase during the -summer months. At Santa Ana the rainfall for the year 1894-95 amounted -to 50 inches, of which 60 per cent fell between December and March. For -a discussion of topographic features that have some highly interesting -climatic effects in the eastern valleys of Peru see Chapter VI. - -[Illustration: FIGS. 116-118--Temperature curves for locations in the -Maritime Cordillera and its western valleys, October, 1911. For -construction of curves see Figs. 109-113. Fig. 116 is for Camp 13 on the -northern slope of the Maritime Cordillera (which here runs from east to -west), October 13-15; Fig. 117 for Cotahuasi, October 26; Fig. 118 for -Salamanca, October 31.] - -[Illustration: FIG. 119. - -FIG. 120. - -FIGS. 119-120--Temperature curves for the Coast Desert, November, 1911. -Fig. 119 is for Aplao, November 4 and 5; and Fig. 120 for Camaná, -November 9 and 10. For construction of curves see Figs. 109 to 113.] - -Abancay, 8,000 feet (2,440 m.), in one of the inter-Andean basins, is -situated in the zone of marked seasonal precipitation. The single day’s -record shows the characteristic effect of cloud reducing the maximum -temperature of the day and maintaining the relative humidity. - -Camp 13, 15,400 feet (4,720 m.), lies near the crest of the Maritime -Cordillera a little south of Antabamba. Afternoon storms are one of its -most significant features. Cotahuasi, 9,100 feet (2,775 m.) is near the -head of a west-coast valley. Its low humidity is worthy of note. That -for Salamanca, 12,700 feet (3,870 m.), is similar but not so marked. - -Aplao, 3,100 feet (945 m.), and Camaná at the seacoast are stations in -the west-coast desert. The interior location of the former gives it a -greater range of temperature than Camaná, yet even here the range is -small in comparison with the diurnal extremes of the montaña, and the -tempering effect of the sea-breeze is clearly apparent. Camaná shows a -diurnal temperature range of under 10° F. and also the high relative -humidity, over 70 per cent, characteristic of the coast. - - - - -PART II - -PHYSIOGRAPHY OF THE PERUVIAN ANDES - - - - -CHAPTER XI - -THE PERUVIAN LANDSCAPE - - -From the west coast the great Andean Cordillera appears to have little -of the regularity suggested by our relief maps. Steep and high cliffs in -many places form the border of the land and obstruct the view; beyond -them appear distant summits rising into the zone of clouds. Where the -cliffs are absent or low, one may look across a sun-baked, yellow -landscape, generally broken by irregular foothills that in turn merge -into the massive outer spurs and ranges of the mountain zone. The plain -is interrupted by widely separated valleys whose green lowland meadows -form a brilliant contrast to the monotonous browns and yellows of the -shimmering desert. In rare situations the valley trenches enable one to -look far into the Cordillera and to catch memorable glimpses of lofty -peaks capped with snow. - -If the traveler come to the west-coast landscape from the well-molded -English hills or the subdued mountains of Vermont and New Hampshire with -their artistic blending of moderate profiles, he will at first see -nothing but disorder. The scenery will be impressive and, in places, -extraordinary, but it is apparently composed of elements of the greatest -diversity. All the conceivable variations of form and color are -expressed, with a predominance of bold rugged aspects that give a -majestic appearance to the mountain-bordered shore. One looks in vain -for some sign of a quiet view, for some uniformity of features, for some -landscape that will remind him of the familiar hills of home. The Andes -are aggressive mountains that front the sea in formidable spurs or -desert ranges. Could we see in one view their entire elevation from -depths of over 20,000 feet beneath sea level to snowy summits, a total -altitude of 40,000 feet (12,200 m.), their excessive boldness would be -more apparent. No other mountains in the world are at once so -continuously lofty and so near a coast which drops off to abyssal -depths. - -The view from the shore is, however, but one of many which the Andes -exhibit. Seen from the base the towering ranges display a stern aspect, -but, like all mountains, their highest slopes and spurs must be crossed -and re-crossed before the student is aware of other aspects of a quite -different nature. The Andes must be observed from at least three -situations: from the floors of the deep intermontane valleys, from the -intermediate slopes and summits, and from the uppermost levels as along -the range crests and the highest passes. Strangely enough it is in the -summit views that one sees the softest forms. At elevations of 14,000 to -16,000 feet (4,270 to 4,880 m.), where one would expect rugged spurs, -serrate chains, and sharp needles and horns, one comes frequently upon -slopes as well graded as those of a city park--grass-covered, -waste-cloaked, and with gentle declivity (Figs. 121-124). - -The graded, waste-cloaked slopes of the higher levels are interpreted as -the result of prolonged denudation in an erosion cycle which persisted -through the greater part of the Tertiary period, and which was closed by -uplifts aggregating at least several thousands of feet. Above the level -of the mature slopes rise the ragged profiles and steep, naked -declivities of the snow-capped mountains which bear residual relations -to the softer forms at their bases. They are formed upon rock masses of -greater original elevation and of higher resistance to denudation. -Though they are dominating topographic features, they are much less -extensive and significant than the tame landscape which they surmount. - -[Illustration: FIG. 121--Looking north from the hill near Anta in the -Anta basin north of Cuzco. Typical composition of slopes and intermont -basins in the Central Andes. Alluvial fill in the foreground; mature -slopes in the background; in the extreme background the snow-capped -crests of the Cordillera Vilcapampa.] - -[Illustration: FIG. 122--Showing topographic conditions before the -formation of the deep canyons in the Maritime Cordillera. The view, -looking across a tributary canyon of the Antabamba river, shows in the -background the main canyon above Huadquirca. Compare with Fig. 60.] - -Below the level of the mature slopes are topographic features of equal -prominence: gorges and canyons up to 7,000 feet deep. The deeply -intrenched streams are broken by waterfalls and almost continuous -rapids, the valley walls are so abrupt that one may, in places, roll -stones down a 4,000 foot incline to the river bed, and the tortuous -trail now follows a stream in the depths of a profound abyss, now scales -the walls of a labyrinthine canyon. - -[Illustration: FIG. 123--Mature slopes between Ollantaytambo and -Urubamba.] - -[Illustration: FIG. 124--Dissected mature slopes north of Anta in the -Anta basin north of Cuzco.] - -[Illustration: FIG. 125--Mature upper and young lower slopes at the -outlet of the Cuzco basin.] - -The most striking elements of scenery are not commonly the most -important in physiography. The oldest and most significant surface may -be at the top of the country, where it is not seen by the traveler or -where it cannot impress him, except in contrast to features of greater -height or color. The layman frequently seizes on a piece of bad-land -erosion or an outcrop of bright-colored sandstone or a cliff of -variegated clays or a snow-covered mountain as of most interest. All we -can see of a beautiful snow-clad peak is mere entertainment compared -with what subdued waste-cloaked hill-slopes may show. We do not wish to -imply that everywhere the tops of the Andes are meadows, that there are -no great scenic features in the Peruvian mountains, or that they are not -worth while. But we do wish to say that the bold features are far less -important in the interpretation of the landscape. - -Amid all the variable forms of the Peruvian Cordillera certain strongly -developed types recur persistently. That their importance and relation -may be appreciated we shall at once name them categorically and -represent them in the form of a block diagram (Fig. 126). The principal -topographic types are as follows: - - 1. An extensive system of high-level, well-graded, mature slopes, - below which are: - - 2. Deep canyons with steep, and in places, cliffed sides and narrow - floors, and above which are: - - 3. Lofty residual mountains composed of resistant, highly deformed - rock, now sculptured into a maze of serrate ridges and sharp - commanding peaks. - - 4. Among the forms of high importance, yet causally unrelated to - the other closely associated types, are the volcanic cones and - plateaus of the western Cordillera. - - 5. At the valley heads are a full complement of glacial features, - such as cirques, hanging valleys, reversed slopes, terminal - moraines, and valley trains. - - 6. Finally there is in all the valley bottoms a deep alluvial fill - formed during the glacial period and now in process of dissection. - -Though there are in many places special features either remotely related -or quite unrelated to the principal enumerated types, they belong to the -class of minor forms to which relatively small attention will be paid, -since they are in general of small extent and of purely local interest. - -[Illustration: FIG. 126--Block diagram of the typical physiographic -features of the Peruvian Andes.] - -The block diagram represents all of these features, though of necessity -somewhat more closely associated than they occur in nature. Reference to -the photographs, Figs. 121-124, will make it clear that the diagram is -somewhat ideal: on the other hand the photographs together include all -the features which the diagram displays. In descending from any of the -higher passes to the valley floor one passes in succession down a steep, -well-like cirque at a glaciated valley head, across a rocky terminal -moraine, then down a stair-like trail cut into the steep scarps which -everywhere mark the descent to the main valley floors, over one after -another of the confluent alluvial fans that together constitute a large -part of the valley fill, and finally down the steep sides of the inner -valley to the boulder-strewn bed of the ungraded river. - -We shall now turn to each group of features for description and -explanation, selecting for first consideration the forms of widest -development and greatest significance--the high-level mature slopes -lying between the lofty mountains which rise above them and the deep, -steep-walled valleys sunk far below them. These are the great pasture -lands of the Cordillera; their higher portions constitute the typical -_puna_ of the Indian shepherds. In many sections it is possible to -pasture the vagrant flocks almost anywhere upon the graded slopes, -confident that the _ichu_, a tufted forage grass, will not fail and that -scattered brooks and springs will supply the necessary water. At -nightfall the flocks are driven down between the sheltering walls of a -canyon or in the lee of a cliff near the base of a mountain, or, failing -to reach either of these camps, the shepherd confines his charge within -the stone walls of an isolated corral. - -In those places where the graded soil-covered slopes lie within the zone -of agriculture--below 14,000 feet--they are cultivated, and if the soil -be deep and fertile they are very intensively cultivated. Between Anta -and Urubamba, a day’s march north of Cuzco, the hill slopes are covered -with wheat and barley fields which extend right up to the summits (Fig. -134). In contrast are the uncultivated soil-less slopes of the mountains -and the bare valley walls of the deeply intrenched streams. The -distribution of the fields thus brings out strongly the principal -topographic relations. Where the softer slopes are at too high a level, -the climatic conditions are extreme and man is confined to the valley -floors and lower slopes where a laborious system of terracing is the -first requirement of agriculture. - -The appearance of the country after the mature slopes had been formed is -brought out in Fig. 122. The camera is placed on the floor of a still -undissected, mature valley which shows in the foreground of the -photograph. In the middle distance is a valley whose great depth and -steepness are purposely hidden; beyond the valley are the smoothly -graded, catenary curves, and interlocking spurs of the mature upland. In -imagination one sees the valleys filled and the valley slopes confluent -on the former (now imaginary) valley floor which extends without -important change of expression to the border of the Cordillera. No -extensive cliffs occur on the restored surface, and none now occur on -large tracts of the still undissected upland. Since the mature slopes -represent a long period of weathering and erosion, their surfaces were -covered with a deep layer of soil. Where glaciation at the higher levels -and vigorous erosion along the canyons have taken place, the former soil -cover has been removed; elsewhere it is an important feature. Its -presence lends a marked softness and beauty to these lofty though -subdued landscapes. - -The graded mountain slopes were not all developed (1) at the same -elevation, nor (2) upon rock of the same resistance to denudation, nor -(3) at the same distance from the major streams, nor (4) upon rock of -the same structure. It follows that they will not all display precisely -the same form. Upon the softer rocks at the lowest levels near the -largest streams the surface was worn down to extremely moderate slopes -with a local relief of not more than several hundred feet. Conversely, -there are quite unreduced portions whose irregularities have mountainous -proportions, and between these extremes are almost all possible -variations. Though the term _mature_ in a broad way expresses the stage -of development which the land had reached, _post mature_ should be -applied to those portions which suffered the maximum reduction and now -exhibit the softest profiles. At no place along the 73rd meridian was -denudation carried to the point of even local peneplanation. All of the -major and some of the minor divides bear residual elevations and even -approximately plane surfaces do not exist. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM, DIRECTOR - -COROPUNA QUADRANGLE - -(_Cotahuasi_)] - -Among the most important features of the mature slopes are (1) their -great areal extent--they are exhibited throughout the whole Central -Andes, (2) their persistent development upon rocks of whatever structure -or degree of hardness, and (3) their present great elevation in spite of -moderate grades indicative of their development at a much lower -altitude. Mature slopes of equivalent form are developed in widely -separated localities in the Central Andes: in every valley about -Cochabamba, Bolivia, at 10,000 feet (3,050 m.); at Crucero Alto in -southern Peru at 14,600 feet (4,450 m.); several hundred miles farther -north at Anta near Cuzco, 11,000 feet to 12,000 feet (3,600 to 3,940 -m.), and Fig. 129 shows typical conditions in the Vilcabamba Valley -along the route of the Yale Peruvian Expedition of 1911. The -characteristic slopes so clearly represented in these four photographs -are the most persistent topographic elements in the physiography of the -Central Andes. - -[Illustration: FIG. 127--Topographic profiles across typical valleys of -southern Peru. They are drawn to scale and the equality of gradient of -the gentler upper slopes is so close that almost any curve would serve -as a composite of the whole. These curves form the basis of the diagram, -Fig. 128, whereby the amount of elevation of the Andes in late geologic -time may be determined. The approximate locations of the profiles are as -follows: 1, Antabamba; 2, Chuquibambilla; 3, upland south of Antabamba; -4, Apurimac Canyon above Pasaje; 5, Abancay; 6, Arma (Cordillera -Vilcapampa); 7, divide above Huancarama; 8, Huascatay; 9, Huasentay, -farther downstream; 10, Rio Pampas. The upper valley in 8 is still -undissected; 7 is practically the same; 8a is at the level which 8 must -reach before its side slopes are as gentle as at the end of the -preceding interrupted cycle.] - -The rock masses upon which the mature slopes were formed range from soft -to hard, from stratified shales, slates, sandstones, conglomerates, and -limestones to volcanics and intrusive granites. While these variations -impose corresponding differences of form, the graded quality of the -slopes is rarely absent. In some places the highly inclined strata are -shown thinly veiled with surface débris, yet so even as to appear -artificially graded. The rock in one place is hard granite, in another a -moderately hard series of lava flows, and again rather weak shales and -sandstones. - -Proof of the rapid and great uplift of certain now lofty mountain ranges -in late geologic time is one of the largest contributions of -physiography to geologic history. Its validity now rests upon a large -body of diversified evidence. In 1907 I crossed the Cordillera Sillilica -of Bolivia and northern Chile and came upon clear evidences of recent -and great uplift. The conclusions presented at that time were tested in -the region studied in 1911, 500 miles farther north, with the result -that it is now possible to state more precisely the dates of origin of -certain prominent topographic forms, and to reconstruct the conditions -which existed before the last great uplift in which the Central Andes -were born. The relation to this general problem of the forms under -discussion will now be considered. - -The gradients of the mature slopes, as we have already seen, are -distinctly moderate. In the Anta region, over an area several hundred -square miles in extent, they run from several degrees to 20° or 30°. -Ten-degree slopes are perhaps most common. If the now dissected slopes -be reconstructed on the basis of many clinometer readings, photographs, -and topographic maps, the result is a series of profiles as in Fig. 127. -If, further, the restored slopes be coördinated over an extensive area -the gradients of the resulting valley floors will run from 3° to 10°. -Finally, if these valley floors be extended westward to the Pacific and -eastward to the Amazon basin, they will be found about 5,000 feet above -sea level and 4,000 feet above the eastern plains. (For explanation of -method and data employed, see the accompanying figures 127-128). It is, -therefore, a justifiable conclusion that since the formation of the -slopes the Andes have been uplifted at least a mile, or, to put it in -another way, the Andes at the time of formation of the mature slopes -were at least a mile lower than they are at present. - -[Illustration: FIG. 128--Composition of slopes and profiles in the -Peruvian Andes. By superimposing the cross profiles of typical valleys -as shown in Fig. 127 a restoration is possible of the longitudinal -profiles of the earlier cycle of erosion. The difference in elevation of -the two profiles gives less than the minimum amount of uplift that must -have occurred. Case A represents a valley in which recent cutting has -not yet reached the valley head. Below the point 1 the profile has been -steepened and lowered by erosion in the current cycle. Above point 1 the -profile is still in the stage it reached in the preceding cycle. In case -B the renewed erosion of the current cycle has reached to the valley -head. Case C represents conditions similar to those in the preceding -cases save that the stream is typical of those that lie nearest the -steep flexed or faulted margins of the Cordillera and discharge to the -low levels of the desert pampa on the west or the tropical plains on the -east.] - -Further proof of recent and great uplift is afforded by the deeply -intrenched streams. After descending the long graded slopes one comes -upon the cliffed canyons with a feeling of consternation. The effect of -powerful erosion, incident upon uplift, is heightened by the ungraded -character of the river bed. Falls and rapids abound, the river profiles -suggest tumultuous descents, and much time will elapse before the river -beds have the regular and moderate gradients of the streams draining the -mature surface before uplift as shown in the profiles by the dotted -lines representing the restored valley floors of the older cycle. Since -the smooth-contoured landscape was formed great changes have taken -place. The streams have changed from completely graded to almost -completely ungraded profiles; in place of a subdued landscape we now -have upland slopes intersected by mile-deep canyons; the high-level -slopes could not have been formed under existing conditions, for they -are being dissected by the present streams. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM, DIRECTOR - -COTAHUASI QUADRANGLE - -(_La Cumbre_)] - -Since the slopes of the land in general undergo progressive changes in -the direction of flatter gradients during a given geographical cycle, it -follows that with the termination of one cycle and the beginning of -another, two sets of slopes will exist and that the gradients of the two -will be unlike. The result is a break in the descent of the slopes from -high to low levels to which the name “topographic unconformity†is now -applied. It will be a prominent feature of the landscape if the higher, -older, and flatter gradients have but little declivity, and the -gradients of the lower younger slopes are very steep. In those places -where the relief of the first cycle was still great at the time of -uplift, the erosion forms of the second cycle may not be differentiated -from those of the first, since both are marked by steep gradients. In -the Central Andes the change in gradient between the higher and lower -slopes is generally well marked. It occurs at variable heights above -the valley floors, though rarely more than 3,000 feet above them. In the -more central tracts, far from the main streams and their associated -canyons, dissection in the present erosion cycle has not yet been -initiated, the mature slopes are still intact, and a topographic -unconformity has not yet been developed. The higher slopes are faced -with rock and topped with slowly moving waste. Ascent of the spur end is -by steep zigzag trails; once the top is gained the trail runs along the -gentler slopes without special difficulties. - -It is worth noting at this point that the surface of erosion still older -than the mature slopes herewith described appears not to have been -developed along the seventy-third meridian of Peru, or if developed at -one time, fragments of it no longer remain. The last well-developed -remnant is southwest of Cuzco, Fig. 130. I have elsewhere described the -character and geographic distribution of this oldest recognizable -surface of the Central Andes.[41] Southern Peru and Bolivia and northern -Chile display its features in what seems an unmistakable manner. The -best locality yet found is in the Desaguadero Valley between Ancoaqui -and Concordia. There one may see thousands of feet of strongly inclined -sediments of varying resistance beveled by a well-developed surface of -erosion whose preserval is owing to a moderate rainfall and to location -in an interior basin.[42] - -The highest surface of a region, if formed during a prolonged period of -erosion, becomes a surface of reference in the determination of the -character and amount of later crustal deformations, having somewhat the -same functions as a key bed in stratigraphic geology. Indeed, concrete -physiographic facts may be the _only_ basis for arguments as to both -epeirogenic and orogenic movements. The following considerations may -show in condensed form the relative value of physiographic evidence: - -1. If movements in the earth’s crust are predominantly _downward_, -sedimentation may be carried on continuously, and a clear geologic -record may be made. - -2. Even if crustal movements are alternately downward and upward, -satisfactory conclusions may be drawn from both (a) the nature of the -buried surfaces of erosion, and (b) the alternating character of the -sediments. - -3. If, however, the deformative processes effect steady or intermittent -uplifts, there may be no sediments, at least within the limits of the -positive crustal units, and a geologic record must be derived not from -sedimentary deposits but from topographic forms. We speak of the _lost -intervals_ represented by stratigraphic breaks or unconformities and -commonly emphasize our ignorance concerning them. The longest, and, from -the human standpoint, the most important, break in the sedimentary -record is that of the present wherever degradation is the predominant -physiographic process. Unlike the others the _lost interval_ of the -present is not lost, if we may so put it, but is in our possession, and -may be definitely described as a concrete thing. It is the physiography -of today. - -Even where long-buried surfaces of erosion are exposed to view, as in -northern Wisconsin, where the Pre-Cambrian paleo-plain projects from -beneath the Paleozoic sediments, or, as in New Jersey and southeastern -Pennsylvania, where the surface developed on the crystalline rocks -became by depression the floor of the Triassic and by more recent uplift -and erosion has been exposed to view,--even in such cases the exposures -are of small extent and give us at best but meager records. In short, -many of the breaks in the geologic record are of such long duration as -to make imperative the use of physiographic principles and methods. The -great Appalachian System of eastern North America has been a land area -practically since the end of the Paleozoic. In the Central Andes the -“lost interval,†from the standpoint of the sedimentary, record, dates -from the close of the Cretaceous, except in a few local intermont basins -partially filled with Tertiary or Pleistocene deposits. Physiographic -interpretations, therefore, serve the double purpose of supplying a part -of the geologic record while at the same time forming a basis for the -scientific study of the surface distribution of living forms. - -The geologic dates of origin of the principal topographic forms of the -Central Andes may be determined with a fair degree of accuracy. Geologic -studies in Peru and Bolivia have emphasized the wide distribution of the -Cretaceous formations. They consist principally of thick limestones -above and sandstones and conglomerates below, and thus represent -extensive marine submergence of the earth’s crust in the Cretaceous -where now there are very lofty mountains. The Cretaceous deposits are -everywhere strongly deformed or uplifted to a great height, and all have -been deeply eroded. They were involved, together with other and much -older sediments, in the erosion cycle which resulted in the development -of the widely extended series of mature slopes already described. From -low scattered island elevations projecting above sea level, as in the -Cretaceous period, the Andes were transformed by compression and uplift -to a rugged mountain belt subjected to deep and powerful erosion. The -products of erosion were in part swept into the adjacent seas, in part -accumulated on the floors of intermont basins, as in the great interior -basins of Titicaca and Poopó. - -Since the early Tertiary strata are themselves deformed from once simple -and approximately horizontal structures and subjected to moderate -tilting and faulting, it follows that mountain-making movements again -affected the region during later Tertiary. They did not, however, -produce extreme effects. They did stimulate erosion and bring about a -reorganization of all the slopes with respect to the new levels. - -This agrees closely with a second line of evidence which rests upon an -independent basis. The alluvial fill which lies upon all the canyon and -valley floors is of glacial origin, as shown by its interlocking -relations with morainal deposits at the valley heads. It is now in -process of dissection and since its deposition in the Pleistocene had -been eroded on the average about 200 feet. Clearly, to form a 3,000-foot -canyon in hard rock requires much more time than to deposit and again -partially to excavate an alluvial fill several hundred feet deep. -Moreover, the glacial material is coarse throughout, and was built up -rapidly and dissected rapidly. In most cases, furthermore, coarse -material at the bottom of the glacial series rests directly upon the -rock of a narrow and ungraded valley floor. From these and allied facts -it is concluded that there is no long time interval represented by the -transitions from degrading to aggrading processes and back again. The -early Pleistocene, therefore, seems quite too short a period in which to -produce the bold forms and effect the deep erosion which marks the -period between the close of the mature cycle and the beginnings of -deposition in the Pleistocene. - -The alternative conclusion is that the greater part of the canyon -cutting was effected in the late Tertiary, and that it continued into -the early Pleistocene until further erosion was halted by changed -climatic conditions and the augmented delivery of land waste to all the -streams. The final development of the well-graded high-level slopes is, -therefore, closely confined to a small portion of the Tertiary. The -closest estimate which the facts support appears to be Miocene or early -Pliocene. It is clear, however, that only the culmination of the period -can be definitely assigned. Erosion was in full progress at the close of -the Cretaceous and by middle Tertiary had effected vast changes in the -landscape. The Tertiary strata are marked by coarse basal deposit and by -thin and very fine top deposits. Though their deformed condition -indicates a period of crustal disturbance, the Tertiary beds give no -indication of wholesale transformations. They indicate chiefly tilting -and moderate and normal faulting. The previously developed effects of -erosion were, therefore, not radically modified. The surface was thus in -large measure prepared by erosion in the early Tertiary for its final -condition of maturity reached during the early Pliocene. - -It seems appropriate, in concluding this chapter, to summarize in its -main outlines the physiography of southern Peru, partly to condense the -extended discussion of the preceding paragraphs, and partly to supply a -background for the three chapters that follow. The outstanding features -are broad plateau areas separated by well-defined “Cordilleras.†The -plateau divisions are not everywhere of the same origin. Those southwest -of Cuzco (Fig. 130), and in the Anta Basin (Fig. 124), northwest of -Cuzco, are due to prolonged erosion and may be defined as peneplane -surfaces uplifted to a great height. They are now bordered on the one -hand by deep valleys and troughs and basins of erosion and deformation; -and, on the other hand, by residual elevations that owe their present -topography to glacial erosion superimposed upon the normal erosion of -the peneplane cycle. The residuals form true mountain chains like the -Cordillera Vilcanota and Cordillera Vilcapampa; the depressions due to -erosion or deformation or both are either basins like those of Anta and -Cuzco or valleys of the canyon type like the Urubamba canyon; the -plateaus are broad rolling surfaces, the punas of the Peruvian Andes. - -There are two other types of plateaus. The one represents a mature stage -in the erosion cycle instead of an ultimate stage; the other is volcanic -in origin. The former is best developed about Antabamba (Figs. 122 and -123), where again deep canyons and residual ranges form the borders of -the plateau remnants. The latter is well developed above Cotahuasi and -in its simplest form is represented in Fig. 133. Its surface is the top -of a vast accumulation of lavas in places over a mile thick. While rough -in detail it is astonishingly smooth in a broad view (Fig. 29). Above it -rise two types of elevations: first, isolated volcanic cones of great -extent surrounded by huge lava flows of considerable relief; and second, -discontinuous lines of peaks where volcanic cones of less extent are -crowded closely together. The former type is displayed on the Coropuna -Quadrangle, the latter on the Cotahuasi and La Cumbre Quadrangles. - -So high is the elevation of the lava plateau, so porous its soil, so dry -the climate, that a few through-flowing streams gather the drainage of a -vast territory and, as in the Grand Canyon country of our West, they -have at long intervals cut profound canyons. The Arma has cut a deep -gorge at Salamanca; the Cotahuasi runs in a canyon in places 7,000 feet -deep; the Majes heads at the edge of the volcanic field in a steep -amphitheatre of majestic proportions. - -Finally, we have the plateaus of the coastal zone. These are plains with -surfaces several thousand feet in elevation separated by gorges several -thousand feet deep. The Pampa de Sihuas is an illustration. The -post-maturely dissected Coast Range separates it from the sea. The -pampas are in general an aggradational product formed in a past age -before uplift initiated the present canyon cycle of erosion. Other -plateaus of the coastal zone are erosion surfaces. The Tablazo de Ica -appears to be of this type. That at Arica, Chile, near the southern -boundary of Peru, is demonstrably of this type with a border on which -marine planation has in places given rise to a broad terrace -effect.[43] - - - - -CHAPTER XII - -THE WESTERN ANDES: THE MARITIME CORDILLERA OR CORDILLERA OCCIDENTAL - - -The Western or Maritime Cordillera of Peru forms part of the great -volcanic field of South America which extends from Argentina to Ecuador. -On the walls of the Cotahuasi Canyon (Fig. 131), there are exposed over -one hundred separate lava flows piled 7,000 feet deep. They overflowed a -mountainous relief, completely burying a limestone range from 2,000 to -4,000 feet high. Finally, upon the surface of the lava plateau new -mountains were formed, a belt of volcanoes 5,000 feet (1,520 m.) high -and from 15,000 to 20,000 feet (4,570 to 6,100 m.) above the sea. There -were vast mud flows, great showers of lapilli, dust, and ashes, and with -these violent disturbances also came many changes in the drainage. Sixty -miles northeast of Cotahuasi the outlet of an unnamed deep valley was -blocked, a lake was formed, and several hundred feet of sediments were -deposited. They are now wasting rapidly, for they lie in the zone of -alternate freezing and thawing, a thousand feet and more below the -snowline. Some of their bad-land forms look like the solid bastions of -an ancient fortress, while others have the delicate beauty of a Japanese -temple. - -Not all the striking effects of vulcanism belong to the remote geologic -past. A day’s journey northeast of Huaynacotas are a group of lakes only -recently hemmed in by flows from the small craters thereabouts. The -fires in some volcanic craters of the Peruvian Andes are still active, -and there is no assurance that devastating flows may not again inundate -the valleys. In the great Pacific zone or girdle of volcanoes the -earth’s crust is yet so unstable that earthquakes occur every year, and -at intervals of a few years they have destructive force. Cotahuasi was -greatly damaged in 1912; Abancay is shaken every few years; and the -violent earthquakes of Cuzco and Arequipa are historic. - -On the eastern margin of the volcanic country the flows thin out and -terminate on the summit of a limestone (Cretaceous) plateau. On the -western margin they descend steeply to the narrow west-coast desert. The -greater part of the lava dips beneath the desert deposits; there are a -few intercalated flows in the deposits themselves, and the youngest -flows--limited in number--have extended down over the inner edge of the -desert. - -The immediate coast of southern Peru is not volcanic. It is composed of -a very hard and ancient granite-gneiss which forms a narrow coastal -range (Fig. 171). It has been subjected to very long and continued -erosion and now exhibits mature erosion forms of great uniformity of -profile and declivity. - -From the outcrops of older rocks beneath the lavas it is possible to -restore in a measure the pre-volcanic topography of the Maritime -Cordillera, In its present altitude it ranges from several thousand to -15,000 feet above sea level. The unburied topography has been smoothed -out; the buried topography is rough (Figs. 29 and 166). The contact -lines between lavas and buried surfaces in the deep Majes and Cotahuasi -valleys are in places excessively serrate. From this, it seems safe to -conclude that the period of vulcanism was so prolonged that great -changes in the unburied relief were effected by the agents of erosion. -Thus, while the dominant process of volcanic upbuilding smoothed the -former rough topography of the Maritime Cordillera, erosion likewise -measurably smoothed the present high extra-volcanic relief in the -central and eastern sections. The effect has been to develop a broad and -sufficiently smooth aspect to the summit topography of the entire Andes -to give them a plateau character. Afterward the whole mountain region -was uplifted about a mile above its former level so that at present it -is also continuously lofty. - -The zone of most intense volcanic action does not coincide with the -highest part of the pre-volcanic topography. If the pre-volcanic relief -were even in a very general way like that which would be exhibited if -the lavas were now removed, we should have to say that the chief -volcanic outbursts took place on the western flank of an old and deeply -dissected limestone range. - -[Illustration: FIG. 129--Composition of slopes at Puquiura, Vilcabamba -Valley, elevation 9,000 feet (2,740 m.). The second prominent spur -entering the valley on the left has a flattish top unrelated to the rock -structure. Like the spurs on the right its blunt end and flat top -indicate an earlier erosion cycle at a lower elevation.] - -[Illustration: FIG. 130--Inclined Paleozoic strata truncated by an -undulating surface of erosion at 15,000 feet, southwest of Cuzco.] - -[Illustration: FIG. 131--Terraced valley slopes at Huaynacotas, -Cotahuasi Valley, at 11,500 feet (3,500 m.). Solimana is in the -background. On the floor of the Cotahuasi Canyon fruit trees grow. At -Huaynacotas corn and potatoes are the chief products. The section is -composed almost entirely of lava. There are over a hundred major flows -aggregating 5,000 to 7,000 feet thick.] - -The volume of the lavas is enormous. They are a mile and a half thick, -nearly a hundred miles wide, and of indefinite extent north and south. -Their addition to the Andes, therefore, _has greatly broadened the zone -of lofty mountains_. Their passes are from 2,000 to 3,000 feet higher -than the passes of the eastern Andes. They have a much smaller number of -valleys sufficiently deep to enjoy a mild climate. Their soil is far -more porous and dry. Their vegetation is more scanty. They more than -double the difficulties of transportation. And, finally, their all but -unpopulated loftier expanses are a great vacant barrier between farms in -the warm valleys of eastern Peru and the ports on the west coast. - -The upbuilding process was not, of course, continuous. There were at -times intervals of quiet, and some of them were long enough to enable -streams to become established. Buried valleys may be observed in a -number of places on the canyon walls, where subsequently lava flows -displaced the streams and initiated new drainage systems. In these quiet -intervals the weathering agents attacked the rock surfaces and formed -soil. There were at least three or four such prolonged periods of -weathering and erosion wherein a land surface was exposed for many -thousands of years, stream systems organized, and a cultivable soil -formed. No evidence has been found, however, that man was there to -cultivate the soil. - -The older valleys cut in the quiet period are mere pygmies beside the -giant canyons of today. The present is the time of dominant erosion. The -forces of vulcanism are at last relatively quiet. Recent flows have -occurred, but they are limited in extent and in effects. They alter only -the minor details of topography and drainage. Were it not for the oases -set in the now deep-cut canyon floors, the lava plateau of the Maritime -Cordillera would probably be the greatest single tract of unoccupied -volcanic country in the world. - -The lava plateau has been dissected to a variable degree. Its high -eastern margin is almost in its original condition. Its western margin -is only a hundred miles from the sea, so that the streams have steep -gradients. In addition, it is lofty enough to have a moderate rainfall. -It is, therefore, deeply and generally dissected. Within the borders of -the plateau the degree of dissection depends chiefly upon position with -respect to the large streams. These were in turn located in an -accidental manner. The repeated upbuilding of the surface by the -extensive outflow of liquid rock obliterated all traces of the earlier -drainage. In the Cotahuasi Canyon the existing stream, working down -through a mile of lavas, at last uncovered and cut straight across a -mountain spur 2,000 feet high. Its course is at right angles to that -pursued by the stream that once drained the spur. It is noteworthy that -the Cotahuasi and adjacent streams take northerly courses and join -Atlantic rivers. The older drainage was directly west to the Pacific. -Thus, vulcanism not only broadened the Andes and increased their height, -but also moved the continental divide still nearer the west coast. - -The glacial features of the western or Maritime Cordillera are of small -extent, partly because vulcanism has added a considerable amount of -material in post-glacial time, partly because the climate is so -exceedingly dry that the snowline lies near the top of the country. The -slopes of the volcanic cones are for the most part deeply recessed on -the southern or shady sides. Above 17,500 feet (5,330 m.) the process of -snow and ice excavation still continues, but the tracts that exceed this -elevation are confined to the loftiest peaks or their immediate -neighborhood. There is a distinct difference between the glacial forms -of the eastern or moister and the western or dryer flanks of this -Cordillera. Only peaks like Coropuna and Solimana near the western -border now bear or ever bore snowfields and glaciers. By contrast the -eastern aspect is heavily glaciated. On La Cumbre Quadrangle, there is a -huge glacial trough at 16,000 feet (4,876 m.), and this extends with -ramifications up into the snowfields that formerly included the highest -country. Prolonged glacial erosion produced a full set of topographic -forms characteristic of the work of Alpine glaciers. Thus, each of the -main mountain chains that make up the Andean system has, like the system -as a whole, a relatively more-dry and a relatively less-dry aspect. The -snowline is, therefore, canted from west to east on each chain as well -as on the system. However, this effect is combined with a solar effect -in an unequal way. In the driest places the solar factor is the more -efficient and the snowline is there canted from north to south. - - - - -CHAPTER XIII - -THE EASTERN ANDES: THE CORDILLERA VILCAPAMPA - - -The culminating range of the eastern Andes is the so-called Cordillera -Vilcapampa. Its numerous, sharp, snow-covered peaks are visible in every -summit view from the central portion of the Andean system almost to the -western border of the Amazon basin. Though the range forms a water -parting nearly five hundred miles long, it is crossed in several places -by large streams that flow through deep canyons bordered by precipitous -cliffs. The Urubamba between Torontoy and Colpani is the finest -illustration. For height and ruggedness the Vilcapampa mountains are -among the most noteworthy in Peru. Furthermore, they display glacial -features on a scale unequaled elsewhere in South America north of the -ice fields of Patagonia. - - -GLACIERS AND GLACIAL FORMS - -One of the most impressive sights in South America is a tropical forest -growing upon a glacial moraine. In many places in eastern Bolivia and -Peru the glaciers of the Ice Age were from 5 to 10 miles long--almost -the size of the Mer de Glace or the famous Rhone glacier. In the Juntas -Valley in eastern Bolivia the tree line is at 10,000 feet (3,050 m.), -but the terminal moraines lie several thousand feet lower. In eastern -Peru the glaciers in many places extended down nearly to the tree line -and in a few places well below it. In the Cordillera Vilcapampa vast -snowfields and glacier systems were spread out over a summit area as -broad as the Southern Appalachians. The snowfields have since shrunk to -the higher mountain recesses; the glaciers have retreated for the most -part to the valley heads or the cirque floors; and the lower limit of -perpetual snow has been raised to 15,500 feet. - -[Illustration: FIG. 132--Recessed volcanoes in the right background and -eroded tuffs, ash beds, and lava flows on the left. Maritime Cordillera -above Cotahuasi.] - -[Illustration: FIG. 133--The summit of the great lava plateau above -Cotahuasi on the trail to Antabamba. The lavas are a mile and a half in -thickness. The elevation is 16,000 feet. Hence the volcanoes in the -background, 17,000 feet above sea level, are mere hills on the surface -of the lofty plateau.] - -[Illustration: FIG. 134--Southwestern aspect of the Cordillera -Vilcapampa between Anta and Urubamba from Lake Huaipo. Rugged summit -topography in the background, graded post-mature slopes in the middle -distance, and solution lake in limestone in the foreground.] - -[Illustration: FIG. 135--Summit view, Cordillera Vilcapampa. There are -fifteen glaciers represented in this photograph. The camera stands on -the summit of a minor divide in the zone of nivation.] - -These features are surprising because neither Whymper[44] nor Wolf[45] -mentions the former greater extent of the ice on the volcanoes of -Ecuador, only ten or twelve degrees farther north. Moreover, Reiss[46] -denies that the hypothesis of universal climatic change is supported by -the facts of a limited glaciation in the High Andes of Ecuador; and J. -W. Gregory[47] completely overlooks published proof of the existence of -former more extensive glaciers elsewhere in the Andes: - -“... the absence not only of any traces of former more extensive -glaciation from the tropics, as in the Andes and Kilimandjaro, but also -from the Cape.†He says further: “In spite of the extensive glaciers now -in existence on the higher peaks of the Andes, there is practically no -evidence of their former greater extension.â€(!) - -Whymper spent most of his time in exploring recent volcanoes or those -recently in eruption, hence did not have the most favorable -opportunities for gathering significant data. Reiss was carried off his -feet by the attractiveness of the hypothesis[48] relating to the effect -of glacial denudation on the elevation of the snowline. Gregory appeared -not to have recognized the work of Hettner on the Cordillera of Bogotá -and of Sievers[49] and Acosta on the Sierra Nevada de Santa Marta in -northern Colombia. - -The importance of the glacial features of the Cordillera Vilcapampa -developed on a great scale in very low latitudes in the southern -hemisphere is twofold: first, it bears on the still unsettled problem of -the universality of a colder climate in the Pleistocene, and, second, it -supplies additional data on the relative depression of the snowline in -glacial times in the tropics. Snow-clad mountains near the equator are -really quite rare. Mount Kenia rising from a great jungle on the -equator, Kilimandjaro with its two peaks, Kibo and Mawenzi, two hundred -miles farther south, and Ingomwimbi in the Ruwenzori group thirty miles -north of the equator, are the chief African examples. A few mountains -from the East Indies, such as Kinibalu in Borneo, latitude 6° north, -have been found glaciated, though now without a snow cover. In higher -latitudes evidences of an earlier extensive glaciation have been -gathered chiefly from South America, whose extension 13° north and 56° -south of the equator, combined with the great height of its dominating -Cordillera, give it unrivaled distinction in the study of mountain -glaciation in the tropics. - -Furthermore, mountain summits in tropical lands are delicate climatic -registers. In this respect they compare favorably with the inclosed -basins of arid regions, where changes in climate are clearly recorded in -shoreline phenomena of a familiar kind. Lofty mountains in the tropics -are in a sense inverted basins, the lower snowline of the past is like -the higher shoreline of an interior basin; the terminal moraines and the -alluvial fans in front of them are like the alluvial fans above the -highest strandline; the present snow cover is restricted to mountain -summits of small areal extent, just as the present water bodies are -restricted to the lowest portions of the interior basin; and successive -retreatal stages are marked by terminal moraines in the one case as they -are marked in the other by flights of terraces and beach ridges. - -I made only a rapid reconnaissance across the Cordillera Vilcapampa in -the winter season, and cannot pretend from my limited observations to -solve many of the problems of the field. The data are incorporated -chiefly in the chapter on Glacial Features. In this place it is proposed -to describe only the more prominent glacial features, leaving to later -expeditions the detailed descriptions upon which the solution of some of -the larger problems must depend. - -At Choquetira three prominent stages in the retreat of the ice are -recorded. The lowermost stage is represented by the great fill of -morainic and outwash material at the junction of the Choquetira, and an -unnamed valley farther south at an elevation of 11,500 feet (3,500 m.). -A mile below Choquetira a second moraine appears, elevation 12,000 feet -(3,658 m.), and immediately above the village a third at 12,800 (3,900 -m.). The lowermost moraine is well dissected, the second is ravined and -broken but topographically distinct, the third is sharp-crested and -regular. A fourth though minor stage is represented by the moraine at -the snout of the living glacier and still less important phases are -represented in some valleys--possibly the record of post-glacial changes -of climate. Each main moraine is marked by an important amount of -outwash, the first and third moraines being associated with the greatest -masses. The material in the moraines represents only a part of that -removed to form the successive steps in the valley profile. The -lowermost one has an enormous volume, since it is the oldest and was -built at a time when the valley was full of waste. It is fronted by a -deep fill, over the dissected edge of which one may descend 800 feet in -half an hour. It is chiefly alluvial in character, whereas the next -higher one is composed chiefly of bowlders and is fronted by a -pronounced bowlder train, which includes a remarkable perched bowlder of -huge size. Once the valley became cleaned out the ice would derive its -material chiefly by the slower process of plucking and abrasion, hence -would build much smaller moraines during later recessional stages, even -though the stages were of equivalent length. - -[Illustration: FIG. 136--Glacial sculpture on the southwestern flank of -the Cordillera Vilcapampa. Flat-floored valleys and looped terminal -moraines below and glacial steps and hanging valleys are characteristic. -The present snowfields and glaciers are shown by dotted contours.] - -There is a marked difference in the degree of dissection of the -moraines. The lowermost and oldest is so thoroughly dissected as to -exhibit but little of its original surface. The second has been greatly -modified, but still possesses a ridge-like quality and marks the -beginning of a noteworthy flattening of the valley gradient. The third -is as sharp-crested as a roof, and yet was built so long ago that the -flat valley floor behind it has been modified by the meandering stream. -From this point the glacier retreated up-valley several miles -(estimated) without leaving more than the thinnest veneer on the valley -floor. The retreat must, therefore, have been rapid and without even -temporary halts until the glacier reached a position near that occupied -today. Both the present ice tongues and snowfields and those of a past -age are emphasized by the presence of a patch of scrub and woodland that -extends on the north side of the valley from near the snowline down over -the glacial forms to the lower valley levels. - -The retreatal stages sketched above would call for no special comment if -they were encountered in mountains in northern latitudes. They would be -recognized at once as evidence of successive periodic retreats of the -ice, due to successive changes in temperature. To understand their -importance when encountered in very low latitudes it is necessary to -turn aside for a moment and consider two rival hypotheses of glacial -retreat. First we have the hypothesis of periodic retreat, so generally -applied to terminal moraines and associated outwash in glaciated -mountain valleys. This implies also an advance of the ice from a higher -position, the whole taking place as a result of a climatic change from -warmer to colder and back again to warmer. - -[Illustration: FIG. 137--Looking up a spurless flat-floored glacial -trough near the Chucuito pass in the Cordillera Vilcapampa from 14,200 -feet (4,330 m.). Note the looped terminal and lateral moraines on the -steep valley wall on the left. A stone fence from wall to wall serves to -inclose the flock of the mountain shepherd.] - -[Illustration: FIG. 138--Terminal moraine in the glaciated Choquetira -Valley below Choquetira. The people who live here have an abundance of -stones for building corrals and stone houses. The upper edge of the -timber belt (cold timber line) is visible beyond the houses. Elevation -12,100 feet (3,690 m.).] - -But evidences of more extensive mountain glaciation in the past do not -in themselves prove a change in climate over the whole earth. In an -epoch of fixed climate a glacier system may so deeply and thoroughly -erode a mountain mass, that the former glaciers may either diminish in -size or disappear altogether. As the work of excavation proceeds, the -catchment basins are sunk to, and at last below, the snowline; broad -tributary spurs whose snows nourish the glaciers, may be reduced to -narrow or skeleton ridges with little snow to contribute to the valleys -on either hand; the glaciers retreat and at last disappear. There -would be evidences of glaciation all about the ruins of the former -loftier mountain, but there would be no living glaciers. And yet the -climate might remain the same throughout. - -It is this “topographic†hypothesis that Reiss and Stübel accept for the -Ecuadorean volcanoes. Moreover, the volcanoes of Ecuador are practically -on the equator--a very critical situation when we wish to use the facts -they exhibit in the solution of such large problems as the -contemporaneous glaciation of the two hemispheres, or the periodic -advance and retreat of the ice over the whole earth. This is not the -place to scrutinize either their facts or their hypothesis, but I am -under obligations to state very emphatically that the glacial features -of the Cordillera Vilcapampa require the climatic and not the -topographic hypothesis. Let us see why. - -The differences in degree of dissection and the flattening gradient -up-valley that we noted in a preceding paragraph leave no doubt that -each moraine of the bordering valleys in the Vilcapampa region, -represents a prolonged period of stability in the conditions of -topography as well as of temperature and precipitation. If change in -topographic conditions is invoked to explain retreat from one position -to the other there is left no explanation of the periodicity of retreat -which has just been established. If a period of cold is inaugurated and -glaciers advance to an ultimate position, they can retreat only through -change of climate effected either by general causes or by topographic -development to the point where the snowfields become restricted in size. -In the case of climatic change the ice changes are periodic. In the case -of retreat due to topographic change there should be a steady or -non-periodic falling back of the ice front as the catchment basins -decrease in elevation and the snow-gathering ridges tributary to them -are reduced in height. - -Further, the matterhorns of the Cordillera Vilcapampa are not bare but -snow-covered, vigorous glaciers several miles in length and large -snowfields still survive and the divides are not arêtes but broad -ridges. In addition, the last two moraines, composed of very loose -material, are well preserved. They indicate clearly that the time since -their formation has witnessed no wholesale topographic change. If (1) no -important topographic changes have taken place, and (2) a vigorous -glacier lay for a long period back of a given moraine, and (3) _suddenly -retreated several miles and again became stable_, we are left without -confidence in the application of the topographic hypothesis to the -glacial features of the Vilcapampa region. Glacial retreat may be -suddenly begun in the case of a late stage of topographic development, -but it should be an orderly retreat marked by a large number of small -moraines, or at least a plentiful strewing of the valley floor with -débris. - -[Illustration: FIG. 139--Glacial features on the eastern slopes of the -Cordillera Vilcapampa.] - -The number of moraines in the various glaciated valleys of the -Cordillera Vilcapampa differ, owing to differences in elevation and to -the variable size of the catchment basins. All valleys, however, display -the same sudden change from moraine to moraine and the same -characteristics of gradient. In all of them the lowermost moraine is -always more deeply eroded than the higher moraines, in all of them -glacial erosion was sufficiently prolonged greatly to modify the valley -walls, scour out lake basins, or broad flat valley floors, develop -cirques, arêtes, and pinnacled ridges in limited number. In some, -glaciation was carried to the point where only skeleton divides -remained, in most places broad massive ridges or mountain knots persist. -In spite of all these differences successive moraines were formed, -separated by long stretches either thinly covered with till or exposing -bare rock. - -In examining this group of features it is important to recognize the -essential fact that though the number of moraines varies from valley to -valley, the differences in character between the moraines at low and at -high elevations in a single valley are constant. It is also clear that -everywhere the ice retreated and advanced periodically, no matter with -what topographic features it was associated, whether those of maturity -or of youth in the glacial cycle. We, therefore, conclude that -topographic changes had no significant part to play in the glacial -variations in the Cordillera Vilcapampa. - -The country west of the Cordillera Vilcapampa had been reduced to early -topographic maturity before the Ice Age, and then uplifted with only -moderate erosion of the masses of the interfluves. That on the east had -passed through the same sequence of events, but erosion had been carried -much farther. The reason for this is found in a strong climatic -contrast. The eastern is the windward aspect and receives much more rain -than the western. Therefore, it has more streams and more rapid -dissection. The result was that the eastern slopes were cut to pieces -rapidly after the last great regional uplift; the broad interfluves were -narrowed to ridges. The region eastward from the crest of the Cordillera -to the Pongo de Mainique looks very much like the western half of the -Cascade Mountains in Oregon--the summit tracts of moderate declivity are -almost all consumed. - -The effect of these climatic and topographic contrasts is manifested in -strong contrasts in the position and character of the glacial forms on -the opposite slopes of the range. At Pampaconas on the east the -lowermost terminal moraine is at least a thousand feet below timber -line. Between Vilcabamba pueblo and Puquiura the terminal moraine lies -at 11,200 feet (3,414 m.). By contrast the largest Pleistocene glacier -on the western slope, nearly twelve miles long, and the largest along -the traverse, ended several miles below Choquetira at 11,500 feet (3,504 -m.) elevation, or just at the timber line. Thus, the steeper descents of -the eastern side of the range appear to have carried short glaciers to -levels far lower than those attained by the glaciers of the western -slope. - -It seems at first strange that the largest glaciers were west of the -divide between the Urubamba and the Apurimac, that is, on the relatively -dry side of the range. The reason lies in a striking combination of -topographic and climatic conditions. Snow is a mobile form of -precipitation that is shifted about by the wind like a sand dune in the -desert. It is not required, like water, to begin a downhill movement as -soon as it strikes the earth. Thus, it is a noteworthy fact that snow -drifting across the divides may ultimately cause the largest snowfields -to lie where the least snow actually falls. This is illustrated in the -Bighorns of Wyoming and others of our western ranges. It is, however, -not the wet snow near the snowline, but chiefly the dry snow of higher -altitudes that is affected. What is now the dry or leeward side of the -Cordillera appears in glacial times to have actually received more snow -than the wet windward side. - -[Illustration: FIG. 140--Glacial sculpture in the heart of the -Cordillera Vilcapampa. In places the topography has so high a relief -that the glaciers seem almost to overhang the valleys. See Figs. 96 and -179 for photographs.] - -The topography conspired to increase this contrast. In place of many -streams, direct descents, a dispersion of snow in many valleys, as on -the east, the western slopes had indirect descents, gentler valley -profiles, and that higher degree of concentration of drainage which -naturally goes with topographic maturity. For example, there is nothing -in the east to compare with the big spurless valley near the pass above -Arma. The side walls were so extensively trimmed that the valley was -turned into a trough. The floor was smoothed and deepened and all the -tributary glaciers were either left high up on the bordering slopes or -entered the main valley with very steep profiles; their lateral and -terminal moraines now hang in festoons on the steep side walls. -Moreover, the range crest is trimmed from the west so that the serrate -skyline is a feature rarely seen from eastern viewpoints. This may not -hold true for more than a small part of the Cordillera. It was probably -emphasized here less by the contrasts already noted than by the geologic -structure. The eastward-flowing glaciers descended over dip slopes on -highly inclined sandstones, as at Pampaconas. Those flowing westward -worked either in a jointed granite or on the outcropping _edges_ of the -sandstones, where the quarrying process known as glacial plucking -permitted the development of excessively steep slopes. - -There are few glacial steps in the eastern valleys. The western valleys -have a marvelous display of this striking glacial feature. The -accompanying hachure maps show them so well that little description is -needed. They are from 50 to 200 feet high. Each one has a lake at its -foot into which the divided stream trickles over charming waterfalls. -All of them are clearly associated with a change in the volume of the -glacier that carved the valley. Wherever a tributary glacier entered, or -the side slopes increased notably in area, a step was formed. By retreat -some of them became divided, for the process once begun would push the -step far up valley after the manner of an extinguishing waterfall. - -The retreat of the steps, the abrasion of the rock, and the sapping of -the cirques at the valley heads excavated the upper valleys so deeply -that they are nearly all, as W. D. Johnson has put it, “down at the -heel.†Thus, above Arma, one plunges suddenly from the smooth, grassy -glades of the strongly glaciated valley head down over the outer slopes -of the lowermost terminal moraine to the steep lower valley. Above the -moraine are fine pastures, in the steep valley below are thickets and -rocky defiles. There are long quiet reaches in the streams of the -glaciated valley heads besides pretty lakes and marshes. Below, the -stream is swift, almost torrential. Arma itself is built upon alluvial -deposits of glacial origin. A mile farther down the valley is -constricted and steep-walled--really a canyon. - -Though the glaciers have retreated to the summit region, they are by no -means nearing extinction. The clear blue ice of the glacier descending -from Mt. Soiroccocha in the Arma Valley seems almost to hang over the -precipitous valley border. In curious contrast to its suggestion of cold -and storm is the patch of dark green woodland which extends right up to -its border. An earthquake might easily cause the glacier to invade the -woodland. Some of the glaciers between Choquetira and Arma rest on -terminal moraines whose distal faces are from 200 to 300 feet high. The -ice descending southeasterly from Panta Mt. is a good illustration. -Earlier positions of the ice front are marked by equally large moraines. -The one nearest that engaged by the living glacier confines a large lake -that discharges through a gap in the moraine and over a waterfall to the -marshy floor of the valley. - -Retreat has gone so far, however, that there are only a few large -glacier systems. Most of the tributaries have withdrawn toward their -snowfields. In place of the twenty distinct glaciers now lying between -the pass and the terminal moraine below Choquetira, there was in glacial -times one great glacier with twenty minor tributaries. The cirques now -partly filled with damp snow must then have been overflowing with dry -snow above and ice below. Some of the glaciers were over a thousand feet -thick; a few were nearly two thousand feet thick, and the cirques that -fed them held snow and ice at least a half mile deep. Such a remarkably -complete set of glacial features only 700 miles from the equator is -striking evidence of the moist climate on the windward eastern part of -the great Andean Cordillera, of the universal change in climate in the -glacial period, and of the powerful dominating effects of ice erosion in -this region of unsurpassed Alpine relief. - - -THE VILCAPAMPA BATHOLITH AND ITS TOPOGRAPHIC EFFECTS - -[Illustration: FIG. 141--Composite geologic section on the northeastern -border of the Cordillera Vilcapampa, in the vicinity of Pampaconas, to -show the deformative effects of the granite intrusion. There is a -limited amount of limestone near the border of the Cordillera. Both -limestone and sandstone are Carboniferous. See Appendix B. See also -Figs. 142 and 146. The section is about 15 miles long.] - -The main axis of the Cordillera Vilcapampa consists of granite in the -form of a batholith between crystalline schists on the one hand -(southwest), and Carboniferous limestones and sandstones and Silurian -shales and slates on the other (northeast). It is not a domal uplift in -the region in which it was observed in 1911, but an axial intrusion, in -places restricted to a narrow belt not more than a score of miles -across. As we should expect from the variable nature of the invaded -material, the granite belt is not uniform in width nor in the character -of its marginal features. In places the intrusion has produced -strikingly little alteration of the country rock; in other localities -the granite has been injected into the original material in so intimate -a manner as almost completely to alter it, and to give rise to a very -broad zone of highly metamorphosed rock. Furthermore, branches were -developed so that here and there tributary belts of granite extend from -the main mass to a distance of many miles. Outlying batholiths occur -whose common petrographic character and similar manner of occurrence -leave little doubt that they are related abyssally to a common plutonic -mass. - -The Vilcapampa batholith has two highly contrasted borders, whether we -consider the degree of metamorphism of the country rock, the definition -of the border, or the resulting topographic forms. On the northeastern -ridge at Colpani the contact is so sharp that the outstretched arms in -some places embrace typical granite on the one hand and almost -unaltered shales and slates on the other. Inclusions or xenoliths of -shale are common, however, ten and fifteen miles distant, though they -are prominent features in a belt only a few miles wide. The lack of more -intense contact effects is a little remarkable in view of the altered -character of the inclusions, all of which are crystalline in contrast to -the fissile shales from which they are chiefly derived. Inclusions -within a few inches of the border fall into a separate class, since they -show in general but trifling alteration and preserve their original -cleavage plains. It appears that the depth of the intrusion must have -been relatively slight or the intrusion sudden, or both shallow and -sudden, conditions which produce a narrow zone of metamorphosed material -and a sharp contact. - -[Illustration: FIG. 142--The deformative effects of the Vilcapampa -intrusion on the northeastern border of the Cordillera. The deformed -strata are heavy-bedded sandstones and shales and the igneous rocks are -chiefly granites with bordering porphyries. Looking northwest near -Puquiura. For conditions near Pampaconas, looking in the opposite -direction, see Fig. 141. For conditions on the other side of the -Cordillera, see Fig. 146.] - -The relation between shale and granite at Colpani is shown in Fig. 143. -Projections of granite extend several feet into the shale and slate and -generally end in blunt barbs or knobs. In a few places there is an -intimate mixture of irregular slivers and blocks of crystallized -sediments in a granitic groundmass, with sharp lines of demarcation -between igneous and included material. The contact is vertical for at -least several miles. It is probable that other localities on the contact -exhibit much greater modification and invasion of the weak shales and -slates, but at Colpani the phenomena are both simple and restricted in -development. - -[Illustration: FIG. 143--Relation of granite intrusion to schist on the -northeastern border of the Vilcapampa batholith near the bridge of -Colpani, lower end of the granite Canyon of Torontoy. The sections are -from 15 to 25 feet high and represent conditions at different levels -along the well-defined contact.] - -The highly mineralized character of the bordering sedimentary strata, -and the presence of numbers of complementary dikes, nearly identical in -character to those in the parent granite now exposed by erosion over a -broad belt roughly parallel to the contact, supplies a basis for the -inference that the granite may underlie the former at a slight depth, or -may have had far greater metamorphic effects upon its sedimentary roof -than the intruded granite has had upon its sedimentary rim. - -The physiographic features of the contact belt are of special interest. -No available physiographic interpretation of the topography of a -batholith includes a discussion of those topographic and drainage -features that are related to the lithologic character of the intruded -rock, the manner of its intrusion, or the depth of erosion since -intrusion. Yet each one of these factors has a distinct topographic -effect. We shall, therefore, turn aside for a moment from the detailed -discussion of the Vilcapampa region to an examination of several -physiographic principles and then return to the main theme for -applications. - -It is recognized that igneous intrusions are of many varieties and that -even batholithic invasions may take place in rather widely different -ways. Highly heated magmas deeply buried beneath the earth’s surface -produce maximum contact effects, those nearer the surface may force the -strata apart without extreme lithologic alterations of the displaced -beds, while through the stoping process a sedimentary cover may be -largely absorbed and the magmas may even break forth at the surface as -in ordinary vulcanism. If the sedimentary beds have great vertical -variation in resistance, in attitude, and in composition, there may be -afforded an opportunity for the display of quite different effects at -different levels along a given contact, so that a great variety of -physical conditions will be passed by the descending levels of erosion. -At one place erosion may have exposed only the summit of the batholith, -at another the associated dikes and sheets and ramifying branches may be -exposed as in the zone of fracture, at a third point the original zone -of flowage may be reached with characteristic marginal schistosity, -while at still greater depths there may be uncovered a highly -metamorphosed rim of resistant sedimentary rock. - -The mere enumeration of these variable structural features is sufficient -to show how variable we should expect the associated land forms to be. -Were the forms of small extent, or had they but slight distinction upon -comparison with other erosional effects, they would be of little -concern. They are, on the contrary, very extensively developed; they -affect large numbers of lofty mountain ranges besides still larger areas -of old land masses subjected to extensive and deep erosion, thus laying -bare many batholiths long concealed by a thick sedimentary roof. - -The differences between intruded and country rock dependent upon these -diversified conditions of occurrence are increased or diminished -according to the history of the region after batholithic invasion takes -place. Regional metamorphism may subsequently induce new structures or -minimize the effects of the old. Joint systems may be developed, the -planes widely spaced in one group of rocks giving rise to monolithic -masses very resistant to the agents of weathering, while those of an -adjacent group may be so closely spaced as greatly to hasten the rate of -denudation. There may be developed so great a degree of schistosity in -one rock as to give rise (with vigorous erosion) to a serrate -topography; on the other hand the forms developed on the rocks of a -batholith may be massive and coarse-textured. - -To these diversifying conditions may be added many others involving a -large part of the field of dynamic geology. It will perhaps suffice to -mention two others: the stage of erosion and the special features -related to climate. If a given intrusion has been accompanied by an -important amount of uplift or marginal compression, vigorous erosion may -follow, whereupon a chance will be offered for the development of the -greatest contrast in the degree of boldness of topographic forms -developed upon rocks of unequal resistance. Ultimately these contrasts -will diminish in intensity, as in the case of all regional differences -of relief, with progress toward the end of the normal cycle of erosion. -If peneplanation ensue, only feeble topographic differences may mark -the line of contact which was once a prominent topographic feature. With -reference to the effects of climate it may be said simply that a granite -core of batholithic origin may extend above the snowline or above timber -line or into the timbered belt, whereas the invaded rock may occur -largely below these levels with obvious differences in both the rate and -the kind of erosion affecting the intruded mass. - -[Illustration: FIG. 144--Cliffed canyon wall in the Urubamba Valley -between Huadquiña and Torontoy. There is a descent of nearly 2,000 feet -shown in the photograph and it is developed almost wholly along -successive joint planes.] - -[Illustration: FIG. 145--Another aspect of the canyon wall of Fig. 144. -The almost sheer descents are in contrast with the cliff and platform -type of topography characteristic of the Grand Canyon of Colorado.] - -If we apply the foregoing considerations to the Cordillera Vilcapampa, -we shall find some striking illustrations of the principles involved. -The invasion of the granite was accompanied by moderate absorption of -the displaced rock, and more especially by the marginal pushing aside of -the sedimentary rim. The immediate effect must have been to give both -intruded rock and country rock greater height and marked ruggedness. -There followed a period of regional compression and torsion, and the -development of widespread joint systems with strikingly regular -features. In the Silurian shales and slates these joints are closely -spaced; in the granites they are in many places twenty to thirty feet -apart. The shales, therefore, offer many more points of attack and have -weathered down into a smooth-contoured topography boldly overlooked -along the contact by walls and peaks of granite. _In some cases a canyon -wall a mile high is developed entirely on two or three joint planes -inclined at an angle no greater than 15°._ The effect in the granite is -to give a marked boldness of relief, nowhere more strikingly exhibited -than at Huadquiña, below Colpani, where the foot-hill slopes developed -on shales and slates suddenly become moderate. The river flows from a -steep and all but uninhabited canyon into a broad valley whose slopes -are dotted with the terraced _chacras_, or farms, of the mountain -Indians. - -The Torontoy granite is also homogeneous while the shales and slates -together with their more arenaceous associates occur in alternating -belts, a diversity which increases the points of attack and the -complexity of the forms. Tending toward the same result is the greater -hardness of the granite. The tendency of the granite to develop bold -forms is accelerated in lofty valleys disposed about snow-clad peaks, -where glaciers of great size once existed, and where small glaciers -still linger. The plucking action of ice has an excellent chance for -expression, since the granite may be quarried cleanly without the -production of a large amount of spoil which would load the ice and -diminish the intensity of its plucking action. - -As a whole the Central Andes passed through a cycle of erosion in late -Tertiary time which was interrupted by uplift after the general surface -had been reduced to a condition of topographic maturity. Upon the -granites mature slopes are not developed except under special conditions -(1) of elevation as in the small batholith above Chuquibambilla, and (2) -where the granite is itself bordered by resistant schists which have -upheld the surface over a broad transitional belt. Elsewhere the granite -is marked by exceedingly rugged forms: deep steep-walled canyons, -precipitous cirques, matterhorns, and bold and extended escarpments of -erosion. In the shale belt the trails run from valley to valley in every -direction without special difficulties, but in the granite they follow -the rivers closely or cross the axis of the range by carefully selected -routes which generally reach the limit of perpetual snow. Added interest -attaches to these bold topographic forms because of the ruins now found -along the canyon walls, as at Torontoy, or high up on the summit of a -precipitous spur, as at Machu Picchu near the bridge of San Miguel. - -The Vilcapampa batholith is bordered on the southwest by a series of -ancient schists with which the granite sustains quite different -relations. No sharp dividing line is visible, the granite extending -along the planes of foliation for such long distances as in places to -appear almost interbedded with the schists. The relation is all the more -striking in view of the trifling intrusions effected in the case of the -seemingly much weaker shales on the opposite contact. Nor is the -metamorphism of the invaded rock limited to simple intrusion. For -several miles beyond the zone of intenser effects the schists have been -enriched with quartz to such an extent that their original darker color -has been changed to light gray or dull white. At a distance they may -even appear as homogeneous and light-colored as the granite. At distant -points the schists assume a darker hue and take on the characters of a -rather typical mica schist. - -It is probable that the Vilcapampa intrusion is one of a family of -batholiths which further study may show to extend over a much larger -territory. The trail west of Abancay was followed quite closely and -accidentally crosses two small batholiths of peculiar interest. Their -limits were not closely followed out, but were accurately determined at -a number of points and the remaining portion of the contact inferred -from the topography. In the case of the larger area there may indeed be -a connection westward with a larger mass which probably constitutes the -ranges distant some five to ten miles from the line of traverse. - -[Illustration: FIG. 146--Deformative effects on limestone strata of the -granite intrusion on the southwestern border of the Vilcapampa batholith -above Chuquibambilla. Fig. 147 is on the same border of the batholith -several miles farther northwest. The granite mass on the right is a -small outlier of the main batholith looking south. The limestone is -Cretaceous. See Appendix C for locations.] - -These smaller intrusions are remarkable in that they appear to have been -attended by little alteration of either invading or invaded rock, though -the granites were observed to become distinctly more acid in the contact -zone. Space was made for them by displacing the sedimentary cover and by -a marked shortening of the sedimentary rim through such structures as -overthrust faults and folds. The contact is observable in a highly -metamorphosed belt about twenty feet wide, and for several hundred feet -more the granite has absorbed the limestone in small amounts with the -production of new minerals and the development of a distinctly lighter -color. The deformative effects of the batholithic invasion are shown in -their gross details in Figs. 141, 142, and 146; the finer details of -structure are represented in Fig. 147, which is drawn from a measured -outcrop above Chuquibambilla. - -It will be seen that we have here more than a mere crinkling, such as -the mica schists of the Cordillera Vilcapampa display. The diversified -sedimentary series is folded and faulted on a large scale with broad -structural undulations visible for miles along the abrupt valley walls. -Here and there, however, the strata become weaker generally through the -thinning of the beds and the more rapid alternation of hard and soft -layers, and for short distances they have absorbed notable amounts of -the stresses induced by the igneous intrusions. In such places not only -the structure but the composition of the rock shows the effects of the -intrusion. Certain shales in the section are carbonaceous and in all -observed cases the organic matter has been transformed to anthracite, a -condition generally associated with a certain amount of minute mashing -and a cementation of both limestone and sandstone. - -[Illustration: FIG. 147--Overthrust folds in detail on the southwestern -border of the Vilcapampa batholith near Chuquibambilla. The section is -fifteen feet high. Elevation, 13,100 feet (4,000 m.). For comparison -with the structural effects of the Vilcapampa intrusion on the northeast -see Fig. 142.] - -The granite becomes notably darker on approach to the northeastern -contact near Colpani; the proportion of ferro-magnesian minerals in some -cases is so large as to give a distinctly black color in sharp contrast -to the nearly white granite typical of the central portion of the mass. -Large masses of shale foundered in the invading magma, and upon fusion -gave rise to huge black masses impregnated with quartz and in places -smeared or injected with granite magma. Everywhere the granite is marked -by numbers of black masses which appear at first sight to be -aggregations of dark minerals normal to the granite and due to -differentiation processes at the time of crystallization. It is, -however, noteworthy that these increase rapidly in number on approach to -the contact, until in the last half-mile they appear to grade into the -shale inclusions. It may, therefore, be doubted that they are -aggregations. From their universal distribution, their uniform -character, and their marked increase in numbers on approach to lateral -contacts, it may reasonably be inferred that they represent foundered -masses of country rock. Those distant from present contacts are in -almost all cases from a few inches to a foot in diameter, while on -approach to lateral contacts they are in places ten to twenty feet in -width, as if the smaller areas represented the last remnants of large -inclusions engulfed in the magma near the upper or roof contact. They -are so thoroughly injected with silica and also with typical granite -magma as to make their reference to the country rock less secure on -petrographical than on purely distributional grounds. - -A parallel line of evidence relates to the distribution of complementary -dikes throughout the granite. In the main mass of the batholith the -dikes are rather evenly distributed as to kind with a slight -preponderance of the dark-colored group. Near the contact, however, -aplitic dikes cease altogether and great numbers of melanocratic dikes -appear. It may be inferred that we have in this pronounced condition -suggestions of strong influence upon the final processes of invasion and -cooling of the granite magma, on the part of the country rock detached -and absorbed by the invading mass. It might be supposed that the -indicated change in the character of the complementary dikes could be -ascribed to possible differentiation of the granite magma whereby a -darker facies would be developed toward the Colpani contact. It has, -however, been pointed out already that the darkening of the granite in -this direction is intimately related to a marked increase in the number -of inclusions, leaving little doubt that the thorough digestion of the -smaller masses of detached shales is responsible for the marked increase -in the number and variety of the ferro-magnesian and special contact -minerals. - -Upon the southwestern border of the batholith the number of aplitic -dikes greatly increases. They form prominent features, not only of the -granite, but also of the schists, adding greatly to the strong contrast -between the schist of the border zone and that outside the zone of -metamorphism. In places in the border schists, these are so numerous -that one may count up to twenty in a single view, and they range in size -from a few inches to ten or fifteen feet. The greater fissility of the -schists as contrasted with the shales on the opposite or eastern margin -of the batholith caused them to be relatively much more passive in -relation to the granite magma. They were not so much torn off and -incorporated in the magma, as they were thoroughly injected and -metamorphosed. Added to this is the fact that they are petrographically -more closely allied to the granite than are the shales upon the -northeastern contact. - - - - -CHAPTER XIV - -THE COASTAL TERRACES - - -Along the entire coast of Peru are upraised and dissected terraces of -marine origin. They extend from sea level to 1,500 feet above it, and -are best displayed north of Mollendo and in the desert south of Payta. -The following discussion relates to that portion of the coast between -Mollendo and Camaná. - -At the time of the development of the coastal terraces the land was in a -state of temporary equilibrium, for the terraces were cut to a mature -stage as indicated by the following facts: (1) the terraces have great -width--from one to five and more miles; (2) their inner border is -straight, or, where curves exist, they are broad and regular; (3) the -terrace tops are planed off smoothly so that they now have an even -gradient and an almost total absence of rock stacks or unreduced spurs; -(4) the mature slopes of the Coast Range, strikingly uniform in gradient -and stage of development (Fig. 148), are perfectly organized with -respect to the inner edge of the terrace. They descend gradually to the -terrace margin, showing that they were graded with respect to sea level -when the sea stood at the inner edge of the highest terrace. - -From the composition and even distribution of the thick-bedded Tertiary -deposits of the desert east of the Coast Range, it is concluded that the -precipitation of Tertiary time was greater than that of today (see p. -261). Therefore, if the present major streams reach the sea, it may also -be concluded that those of an earlier period reached the sea, provided -the topography indicates the perfect adjustment of streams to structure. -Lacustrine sediments are absent throughout the Tertiary section. Such -through-flowing streams, discharging on a stable coast, would also have -mature valleys as a consequence of long uninterrupted erosion at a fixed -level. The Majes river must have cut through the Coast Range at Camaná -then as now. Likewise the Vitor at Quilca must have cut straight across -the Coast Range. An examination of the surface leading down from the -Coast Range to the upper edge of these valleys fully confirms this -deduction. Flowing and well-graded slopes descend to the brink of the -inner valley in each case, where they give way to the gorge walls that -continue the descent to the valley floor. - -Confirmatory evidence is found in the wide Majes Valley at Cantas and -Aplao. (See the Aplao Quadrangle for details.) Though the observer is -first impressed with the depth of the valley, its width is more -impressive still. It is also clear that two periods of erosion are -represented on its walls. Above Aplao the valley walls swing off to the -west in a great embayment quite inexplicable on structural grounds; in -fact the floor of the embayment is developed across the structure, which -is here more disordered than usual. The same is true below Cantas, as -seen from the trail, which drops over two scarps to get to the valley -floor. The upper, widely opened valley is correlated with the latter -part of the period in which were formed the mature terraces of the coast -and the mature slopes bordering the larger valleys where they cross the -Coast Range. - -After its mature development the well-graded marine terrace was upraised -and dissected. The deepest and broadest incisions in it were made where -the largest streams crossed it. Shallower and narrower valleys were -formed where the smaller streams that headed in the Coast Range flowed -across it. Their depth and breadth was in general proportional to the -height of that part of the Coast Range in which their headwaters lay and -to the size of their catchment basins. - -When the dissection of the terrace had progressed to the point where -about one-third of it had been destroyed, there came depression and the -deposition of Pliocene or early Pleistocene sands, gravels, and local -clay beds. Everywhere the valleys were partly or wholly filled and over -broad stretches, as in the vicinity of stream mouths and upon lower -portions of the terrace, extensive deposits were laid down. The largest -deposits lie several hours’ ride south of Camaná, where locally they -attain a thickness of several hundred feet. Their upper surface was well -graded and they show a prolonged period of deposition in which the -former coastal terrace was all but concealed. - -[Illustration: FIG. 148--The Coast Range between Mollendo and Arequipa -at the end of June, 1911. There is practically no grass and only a few -dry shrubs. The fine network over the hill slopes is composed of -interlacing cattle tracks. The cattle roam over these hills after the -rains which come at long intervals. (See page 141 for description of the -rains and the transformations they effect. For example, in October, -1911, these hills were covered with grass.)] - -[Illustration: FIG. 149--The great marine terrace at Mollendo. See Fig. -150 for profile.] - -The uplift of the coast terrace and its subsequent dissection bring the -physical history down to the present. The uplift was not uniform; three -notches in the terrace show more faintly upon the granite-gneiss where -the buried rock terrace has been swept clean again, more strongly upon -the softer superimposed sands. They lie below the 700-foot contour and -are insignificant in appearance beside the slopes of the Coast Range or -the ragged bluff of the present coast. - -The effect of the last uplift of the coast was to impel the Majes River -again to cut down its lower course nearly to sea level. The Pliocene -terrace deposits are here entirely removed over an area several leagues -wide. In their place an extensive delta and alluvial fan have been -formed. At first the river undoubtedly cut down to base level at its -mouth and deposited the cut material on the sea floor, now shoal, for a -considerable distance from shore. We should still find the river in that -position had other agents not intervened. But in the Pleistocene a great -quantity of waste was swept into the Majes Valley, whereupon aggradation -began; and in the middle and lower valley it has continued down to the -present. - -[Illustration: FIG. 150--Profile of the coastal terraces at Mollendo. At -1, in a tributary gorge, fossiliferous clay occurs at 800 feet elevation -above the sea. At 2 is a characteristic change of profile marking a drop -from a higher to a lower terrace. On the extreme left is the highest -terrace, just under 1,500 feet (460 m.).] - -[Illustration: FIGS. 151-154--These four diagrams represent the physical -history and the corresponding physiographic development of the coastal -region of Peru between Camaná and Mollendo. The sedimentary beds in the -background of the first diagram are hypothetical and are supposed to -correspond to the quartzites of the Majes Valley at Aplao.] - -The effect has been not only the general aggradation of the valley -floor, but also the development of a combined delta and superimposed -alluvial fan at the valley mouth. The seaward extension of the delta has -been hastened by the gradation of the shore between the bounding -headlands, thus giving rise to marine marshes in which every particle of -contributed waste is firmly held. The plain of Camaná, therefore, -includes parts of each of the following: a delta, a superposed alluvial -fan, a salt-water marsh, a fresh-water marsh, a series of beaches, small -amounts of piedmont fringe at the foot of Pliocene deposits once trimmed -by the river and by waves, and extensive tracts of indefinite fill. (See -the Camaná Quadrangle for details.) - -With the coastal conditions now before us it will be possible to attempt -a correlation between the erosion features and the deposits of the coast -and those of the interior. An understanding of the comparisons will be -facilitated by the use of diagrams, Figs. 151-154, and by a series of -concise summary statements. From the relations of the figure it appears -that: - -1. The Tertiary deposits bordering the Majes Valley east of the Coast -Range were in process of deposition when the sea planed the coastal -terrace (Fig. 151). - -2. A broad mature marine terrace without stacks or sharply alternating -spurs and reëntrants (though the rock is a very resistant granite) is -correlated with the mature grades of the Coast Range, with which they -are integrated and with the mature profiles of the main Cordillera. - -3. Such a high degree of topographic organization requires the -dissection in the _late_ stages of the erosion cycle of at least the -inner or eastern border of the piedmont deposits of the desert, largely -accumulated during the _early_ stages of the cycle. - -4. Since the graded slopes of the Coast Range on the one side descend to -a former shore whose elevation is now but 1,500 feet above sea level, -and since only ten to twenty miles inland on the other side of the -range, the same kind of slope extends beneath Tertiary deposits 4,000 -feet above sea level, it appears that aggradation of the outer (or -western) part of the Tertiary deposits on the eastern border of the -Coast Range continued down to the end of the cycle of erosion, though - -5. There must have been an outlet to the sea, since, as we have already -seen, the water supply of the Tertiary was greater than that of today -and the present streams reach the sea. Moreover, the mature upper slopes -and the steep lower slopes of the large valleys make a pronounced -topographic unconformity, showing two cycles of valley development. - -6. Upon uplift of the coast and dissection of the marine terraces at the -foot of the Coast Range, the streams cut deep trenches on the floors of -their former valleys (Fig. 152) and removed (a) large portions of the -coast terrace, and (b) large portions of the Tertiary deposits east of -the Coast Range. - -7. Depression of the coastal terrace and its partial burial meant the -drowning of the lower Majes Valley and its partial filling with marine -and later with terrestrial deposits. It also brought about the partial -filling by stream aggradation of the middle portion of the valley, -causing the valley fill to abut sharply against the steep valley walls. -(See Fig. 155.) - -8. Uplift and dissection of both the terrace and its overlying sediments -would be accompanied by dissection of the former valley fill, provided -that the waste supply was not increased and that the uplift was regional -and approximately equal throughout--not a bowing up of the coast on the -one hand, or an excessive bowing up of the mountains on the other. But -the waste supply has not remained constant, and the uplift has been -greater in the Cordillera than on the coast. Let us proceed to the proof -of these two conclusions, since upon them depends the interpretation of -the later physical history of the coastal valleys. - -[Illustration: FIG. 155--Steep walls in the Majes Valley below Cantas -and the abrupt termination against them of a deep alluvial fill.] - -[Illustration: FIG. 156--Canyon of the Majes River through the Coast -Range north of Camaná. The rock is a granite-gneiss capped by rather -flat-lying sedimentaries.] - -It is known that the Pleistocene was a time of augmented waste delivery. -At the head of the broadly opened Majes Valley there was deposited a -huge mass of extremely coarse waste several hundred feet deep and -several miles long. Forward from it, interstratified with its outer -margin, and continuing the same alluvial grade, is a still greater mass -of finer material which descends to lower levels. The fine material is -deposited on the floor of a valley cut into Tertiary strata, hence it -is younger than the Tertiary. It is now, and has been for some time -past, in process of dissection, hence it was not formed under present -conditions of climate and relief. It is confidently assigned to the -Pleistocene, since this is definitely known to have been a time of -greater precipitation and waste removal on the mountains, and deposition -on the plains and the floors of mountain valleys. Such a conclusion -appears, even on general grounds, to be but a shade less reliable than -if we were able to find in the upper Majes Valley, as in so many other -Andean valleys, similar alluvial deposits interlocked with glacial -moraines and valley trains. - -In regard to the second consideration--the upbowing of the -Cordillera--it may be noted that the valley and slope profiles of the -main Cordillera shown on p. 191, when extended toward the margin of the -mountain belt, lie nearly a mile above the level of the sea on the west -and the Amazon plains on the east. The evidence of regional bowing thus -afforded is checked by the depths of the mountain valleys and the stream -profiles in them. The streams are now sunk from one to three thousand -feet below their former level. Even in the case of three thousand feet -of erosion the stream profiles are still ungraded, the streams -themselves are almost torrential, and from one thousand to three -thousand feet of vertical cutting must still be accomplished before the -profiles will be as gentle and regular as those of the preceding cycle -of erosion, in which were formed the mature slopes now lying high above -the valley floors. - -Further evidence of bowing is afforded by the attitude of the Tertiary -strata themselves, more highly inclined in the case of the older -Tertiary, less highly inclined in the case of the younger Tertiary. It -is noteworthy that the gradient of the present valley floor is -distinctly less than that of the least highly inclined strata. This is -true even where aggradation is now just able to continue, as near the -nodal point of the valley, above Aplao, where cutting ceases and -aggradation begins. (See the Aplao Quadrangle for change of function on -the part of the stream a half mile above Cosos). Such a progressive -steepening of gradients in the direction of the oldest deposits, shows -very clearly a corresponding progression in the growth of the Andes at -intervals throughout the Tertiary. - -Thus we have aggradation in the Tertiary at the foot of the growing -Andes; aggradation in the Pliocene or early Pleistocene on the floor of -a deep valley cut in earlier deposits; aggradation in the glacial epoch; -and aggradation now in progress. Basin deposits within the borders of -the Peruvian Andes are relatively rare. The profound erosion implied by -the development, first of a mature topography across this great -Cordillera, and second of many deep canyons, calls for deposition on an -equally great scale on the mountain borders. The deposits of the western -border are a mile thick, but they are confined to a narrow zone between -the Coast Range and the Cordillera. Whatever material is swept beyond -the immediate coast is deposited in deep ocean water, for the bottom -falls off rapidly. The deposits of the eastern border of the Andes are -carried far out over the Amazon lowland. Those of earlier geologic -periods were largely confined to the mountain border, where they are now -upturned to form the front range of the Andes. The Tertiary deposits of -the eastern border are less restricted, though they appear to have -gathered chiefly in a belt from fifty to one hundred miles wide. - -The deposits of the western border were laid down by short streams -rising on a divide only 100 to 200 miles from the Pacific. Furthermore, -they drain the dry leeward slopes of the Andes. The deposits of the wet -eastern border were made by far larger streams that carry the waste of -nearly the whole Cordillera. Their shoaling effect upon the Amazon -depression must have been a large factor in its steady growth from an -inland sea to a river lowland. - - - - -CHAPTER XV - -PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT - -GENERAL FEATURES - - -In the preceding chapter we employed geologic facts in the determination -of the age of the principal topographic forms. These facts require -further discussion in connection with their closest physiographic allies -if we wish to show how the topography of today originated. There are -many topographic details that have a fundamental relation to structure; -indeed, without a somewhat detailed knowledge of geology only the -broader and more general features of the landscape can be interpreted. -In this chapter we shall therefore refer not to the scenic features as -in a purely topographic description, but to the rock structure and the -fossils. A complete and technical geologic discussion is not desirable, -first, because it should be based upon much more detailed geologic field -work, and second because after all our main purpose is not to discuss -the geologic features _per se_, but the physiographic background which -the geologic facts afford. I make this preliminary observation partly to -indicate the point of view and partly to emphasize the necessity, in a -broad, geographic study, for the reconstruction of the landscapes of the -past. - -The two dominating ranges of the Peruvian Andes, called the Maritime -Cordillera and the Cordillera Vilcapampa, are composed of igneous -rock--the one volcanic lava, the other intrusive granite. The chief rock -belts of the Andes of southern Peru are shown in Fig. 157. The Maritime -Cordillera is bordered on the west by Tertiary strata that rest -unconformably upon Palaeozoic quartzites. It is bordered on the east by -Cretaceous limestones that grade downward into sandstones, shales, and -basal conglomerates. At some places the Cretaceous deposits rest upon -old schists, at others upon Carboniferous limestones and related -strata, upon small granite intrusives and upon old and greatly altered -volcanic rock. - -The Cordillera Vilcapampa has an axis of granitic rock which was thrust -upward through schists that now border it on the west and slates that -now border it on the east. The slate series forms a broad belt which -terminates near the eastern border of the Andes, where the mountains -break down abruptly to the river plains of the Amazon Basin. The -immediate border on the east is formed of vertical Carboniferous -limestones. The narrow foothill belt is composed of Tertiary sandstones -that grade into loose sands and conglomerates. The inclined Tertiary -strata were leveled by erosion and in part overlain by coarse and now -dissected river gravels, probably of Pleistocene age. Well east of the -main border are low ranges that have never been described. They could -not be reached by the present expedition on account of lack of time. On -the extreme western border of that portion of the Peruvian Andes herein -described, there is a second distinct border chain, the Coast Range. It -is composed of granite and once had considerable relief, but erosion has -reduced its former bold forms to gentle slopes and graded profiles. - -The continued and extreme growth of the Andes in later geologic periods -has greatly favored structural and physiographic studies. Successive -uplifts have raised earlier deposits once buried on the mountain flanks -and erosion has opened canyons on whose walls and floors are the clearly -exposed records of the past. In addition there have been igneous -intrusions of great extent that have thrust aside and upturned the -invaded strata exposing still further the internal structures of the -mountains. From sections thus revealed it is possible to outline the -chief events in the history of the Peruvian Andes, though the outline is -still necessarily broad and general because based on rapid -reconnaissance. However, it shows clearly that the landscape of the -present represents but a temporary stage in the evolution of a great -mountain belt. At the dawn of geologic history there were chains of -mountains where the Andes now stand. They were swept away and even their -roots deeply submerged under invading seas. Repeated uplifts of the -earth’s crust reformed the ancient chains or created new ones out of the -rock waste derived from them. Each new set of forms, therefore, exhibits -some features transmitted from the past. Indeed, the landscape of today -is like the human race--inheriting much of its character from past -generations. For this reason the philosophical study of topographic -forms requires at least a broad knowledge of related geologic -structures. - -[Illustration: FIG. 157--Outline sketch showing the principal rock belts -of Peru along the seventy-third meridian. They are: _1_, Pleistocene and -Recent gravels and sands, the former partly indurated and slightly -deformed, with the degree of deformation increasing toward the mountain -border (south). _2_, Tertiary sandstones, inclined from 15° to 30° -toward the north and unconformably overlain by Pleistocene gravels. _3_, -fossil-bearing Carboniferous limestones with vertical dip. _4_, -non-fossiliferous slates, shales, and slaty schists (Silurian) with -great variation in degree of induration and in type of structure. South -of the parallel of 13° is a belt of Carboniferous limestones and -sandstones bordering (_5_), the granite axis of the Cordillera -Vilcapampa. For its structural relations to the Cordillera see Figs. 141 -and 142. _6_, old and greatly disturbed volcanic agglomerates, tuffs and -porphyries, and quartzitic schists and granite-gneiss. _7_, principally -Carboniferous limestones north of the axis of the Central Ranges and -Cretaceous limestones south of it. Local granite batholiths in the axis -of the Central Ranges. _8_, quartzites and slates predominating with -thin limestones locally. South of 8 is a belt of shale, sandstone, and -limestone with a basement quartzite appearing on the valley floors. _9_, -a portion of the great volcanic field of the Central Andes and -characteristically developed in the Western or Maritime Cordillera, -throughout northern Chile, western Bolivia, and Peru. At Cotahuasi (see -also Fig. 20) Cretaceous limestones appear beneath the lavas. _10_, -Tertiary sandstones of the coastal desert with a basement of old -volcanics and quartzites appearing on the valley walls. The valley floor -is aggraded with Pleistocene and Recent alluvium. _11_, granite-gneiss -of the Coast Range. _12_, late Tertiary or Pleistocene sands and gravels -deposited on broad coastal terraces. For rock structure and character -see the other figures in this chapter. For a brief designation of index -fossils and related forms see Appendix B. For the names of the drainage -lines and the locations of the principal towns see Figs. 20 and 204.] - - -SCHISTS AND SILURIAN SLATES[50] - -The oldest series of rocks along the seventy-third meridian of Peru -extends eastward from the Vilcapampa batholith nearly to the border of -the Cordillera, Fig. 157. It consists of (1) a great mass of slates and -shales with remarkable uniformity of composition and structure over -great areas, and (2) older schists and siliceous members in restricted -belts. They are everywhere thoroughly jointed; near the batholith they -are also mineralized and altered from their original condition; in a few -places they have been intruded with dikes and other form of igneous -rock. - -The slates and shales underlie known Carboniferous strata on their -eastern border and appear to be a physical continuation of the -fossiliferous slates of Bolivia; hence they are provisionally referred -to the Silurian, though they may possibly be Devonian. Certainly the -known Devonian exceeds in extent the known Silurian in the Central Andes -but its lithological character is generally quite unlike the character -of the slates here referred to the Silurian. The schists are of great -but unknown age. They are unconformably overlain by known Carboniferous -at Puquiura in the Vilcapampa Valley (Fig. 158), and near Chuquibambilla -on the opposite side of the Cordillera Vilcapampa. The deeply weathered -fissile mica schists east of Pasaje (see Appendix C for all locations) -are also unconformably overlain by conglomerate and sandstone of -Carboniferous age. While the schists vary considerably in lithological -appearance and also in structure, they are everywhere the lowest rocks -in the series and may with confidence be referred to the early -Palaeozoic, while some of them may date from the Proteriozoic. - -[Illustration: FIG. 158--Geologic sketch map of the lower Urubamba -Valley. A single traverse was made along the valley, hence the -boundaries are not accurate in detail. They were sketched in along a few -lateral traverses and also inferred from the topography. The country -rock is schist and the granite intruded in it is an arm of the main -granite mass that constitutes the axis of the Cordillera Vilcapampa. The -structure and to some degree the extent of the sandstone on the left are -represented in Figs. 141 and 142.] - -The Silurian beds are composed of shale, sandstone, shaly sandstone, -limestone, and slate with some slaty schist, among which the shales are -predominent and the limestones least important. Near their contact with -the granite the slate series is composed of alternating beds of -sandstone and shale arranged in beds from one to three feet thick. At -Santa Ana they become more fissile and slaty in character and in several -places are quarried and used for roofing. At Rosalina they consist of -almost uniform beds of shale so soft and so minutely and thoroughly -jointed as to weather easily. Under prolonged erosion they have, -therefore, given rise to a well-rounded and soft-featured landscape. -Farther down the Urubamba Valley they again take on the character of -alternating beds of sandstone and shale from a few feet to fifteen and -more feet thick. In places the metamorphism of the series has been -carried further--the shales have become slates and the sandstones have -been altered to extremely resistant quartzites. The result is again -clearly shown in the topography of the valley wall which becomes bold, -inclosing the river in narrow “pongos†or canyons filled with huge -bowlders and dangerous rapids. The hills become mountains, ledges -appear, and even the heavy forest cover fails to smooth out the natural -ruggedness of the landscape. - -It is only upon their eastern border that the Silurian series includes -calcareous beds, and all of these lie within a few thousand yards of the -contact with the Carboniferous limestones and shales. At first they are -thin paper-like layers; nearer the top they are a few inches wide and -finally attain a thickness of ten or twelve feet. The available -limestone outcrops were rigorously examined for fossils but none were -found, although they are lavishly distributed throughout the younger -Carboniferous beds just above them. It is also remarkable that though -the Silurian age of these beds is reasonably inferred they are not -separated from the Carboniferous by an unconformity, at least we could -find none in this locality. The later beds disconformably overlie the -earlier beds, although the sharp differences in lithology and fossils -make it easy to locate the line of separation. The limestone beds of the -Silurian series are extremely compact and unfossiliferous. At least in -this region those of Carboniferous age are friable and the fossils -varied and abundant. The Silurian beds are everywhere strongly inclined -and throughout the eastern half or third of their outcrop in the -Urubamba Valley they are nearly vertical. - -In view of the enormous thickness of the repeated layers of shale and -sandstone this series is of great interest. Added importance attaches to -their occurrence in a long belt from the eastern edge of the Bolivian -highlands northward through Peru and possibly farther. From the fact -that their disturbance has been on broad lines over wide areas with -extreme metamorphism, they are to be separated from the older -mica-schists and the crumpled chlorite schists of Puquiura and Pasaje. -Further reasons for this distinction lie in their lithologic difference -and, to a more important degree, in the strong unconformity between the -Carboniferous and the schists in contrast to the disconformable -relations shown between the Carboniferous and Silurian fifty miles away -at Pongo de Mainique. The mashing and crumpling that the schists have -experienced at Puquiura is so intense, that were they a part of the -Silurian series the latter should exhibit at least a slight unconformity -in relation to the Carboniferous limestones deposited upon them. - -If our interpretation of the relation of the schists to the slates and -shales be correct, we should have a mountain-making period introduced in -pre-Silurian time, affecting the accumulated sediments and bringing -about their metamorphism and crumpling on a large scale. From the -mountains and uplands thus created on the schists, sediments were washed -into adjacent waters and accumulated as even-bedded and extensive sheets -of sands and muds (the present slates, shales, quartzites, etc.). -Nowhere do the sediments of the slate series show a conglomeratic phase; -they are remarkably well-sorted and consist of material disposed with -great regularity. Though they are coarsest at the bottom the lower beds -do not show cross-bedding, ripple marking, or other signs of -shallow-water conditions. Toward the upper part of the series these -features, especially the ripple-marking, make their appearance. During -the deposition of the last third of the series, and again just before -the deposition of the limestone, the beds took on a predominantly -arenaceous character associated with ripple marks and cross-bedding -characteristic of shallow-water deposits. - -In the persistence of arenaceous sediments throughout the series and the -distribution of the ripple marks through the upper third of the beds, we -have a clear indication that the degree of shallowness was sufficient to -bring the bottom on which the sediments accumulated into the zone of -current action and possibly wave action. It is also worth considering -whether the currents involved were not of similar origin to those now a -part of the great counter-clockwise movements in the southern seas. If -so, their action would be peculiarly effective in the wide distribution -of the sediment derived from a land mass on the eastern edge of a -continental coast, since they would spread out the material to a greater -and greater degree as they flowed into more southerly latitudes. Among -geologic agents a broad ocean current of relatively uniform flow would -produce the most uniform effects throughout a geologic period, in which -many thousand feet of clastic sediments were being accumulated. A -powerful ocean current would also work on flats (in contrast to the -gradient required by near-shore processes), and at the same time be of -such deep and steady flow as to result in neither ripple marks nor -cross-bedding. - -The increasing volume of shallow-water sediments of uniform character -near the end of the Silurian, indicates great crustal stability at a -level which brought about neither a marked gain nor loss of material to -the region. At any rate we have here no Devonian sediments, a -characteristic shared by almost all the great sedimentary formations of -Peru. At the beginning of the Carboniferous the water deepened, and -great heavy-bedded limestones appear with only thin shale partings -through a vertical distance of several hundreds of feet. The enormous -volume of Silurian sediments indicates the deep and prolonged erosion of -the land masses then existing, a conclusion further supported (1) by the -extensive development of the Silurian throughout Bolivia as well as -Peru, (2) by the entire absence of coarse material whether at the top or -bottom of the section, and (3) by the very limited extent of older rock -now exposed even after repeated and irregular uplift and deep -dissection. Indeed, from the latter very striking fact, it may be -reasonably argued that in a general way the relief of the country was -reduced to sea level at the close of the Silurian. Over the perfected -grades of that time there would then be afforded an opportunity for the -effective transportation of waste to the extreme limits of the land. - -Further evidence of the great reduction of surface during the Silurian -and Devonian is supplied by the extensive development of the -Carboniferous strata. Their outcrops are now scattered across the higher -portions of the Andean Cordillera and are prevailingly calcareous in -their upper portions. Upon the eastern border of the Silurian they -indicate marine conditions from the opening of the period, but at Pasaje -in the Apurimac Valley they are marked by heavy beds of basal -conglomerate and sandstone, and an abundance of ripple marking and other -features associated with shallow-water and possibly near-shore -conditions. - - -CARBONIFEROUS - -Carboniferous strata are distributed along the seventy-third meridian -and rival in extent the volcanic material that forms the western border -of the Andes. They range in character from basal conglomerates, -sandstones, and shales of limited development, to enormous beds of -extremely resistant blue limestone, in general well supplied with -fossils. On the eastern border of the Andes they are abruptly terminated -by a great fault, the continuation northward of the marginal fault -recognized in eastern Bolivia by Minchin[51] and farther north by the -writer.[52] Coarse red sandstones with conglomeratic phase abut sharply -and with moderate inclination against almost vertical sandstones and -limestones of Carboniferous age. The break between the vertical -limestones and the gently inclined sandstones is marked by a prominent -scarp nearly four thousand feet high (Fig. 159), and the limestone -itself forms a high ridge through which the Urubamba has cut a narrow -gateway, the celebrated Pongo de Mainique. - -[Illustration: FIG. 159--Topographic and structural section at the -northeastern border of the Peruvian Andes. The slates are probably -Silurian, the fossiliferous limestones are known Carboniferous, and the -sandstones are Tertiary grading up to Pleistocene.] - -At Pasaje, on the western side of the Apurimac, the Carboniferous again -appears resting upon the old schists described on p. 236. It is steeply -upturned, in places vertical, is highly conglomeratic, and in a belt a -half-mile wide it forms true badlands topography. It is succeeded by -evenly bedded sandstones of fine and coarse composition in alternate -beds, then follow shales and sandstones and finally the enormous beds of -limestone that characterize the series. The structure is on the whole -relatively simple in this region, the character and attitude of the beds -indicating their accumulation in a nearly horizontal position. Since the -basal conglomerate contains only pebbles and stones derived from the -subjacent schists and does not contain granites like those in the -Cordillera Vilcapampa batholith on the east it is concluded that the -batholithic invasion was accompanied by the compression and tilting of -the Carboniferous beds and that the batholith itself is -post-Carboniferous. From the ridge summits above Huascatay and in the -deep valleys thereabouts the Carboniferous strata may be seen to extend -far toward the west, and also to have great extent north and south. -Because of their dissected, bare, and, therefore, well-exposed condition -they present exceptional opportunities for the study of Carboniferous -geology in central Peru. - -[Illustration: FIG. 160--The deformative effects of the granite -intrusion of the Cordillera Vilcapampa are here shown as transmitted -through ancient schists to the overlying conglomerates, sandstones, and -limestones of Carboniferous age, in the Apurimac Valley at Pasaje.] - -Carboniferous strata again appear at Puquiura, Vilcapampa, and -Pampaconas. They are sharply upturned against the Vilcapampa batholith -and associated volcanic material, chiefly basalt, porphyry, and various -tuffs and related breccias. The Carboniferous beds are here more -arenaceous, consisting chiefly of alternating beds of sandstone and -shale. The lowermost beds, as at Pongo de Mainique, are dominantly -marine, fossiliferous limestone beds having a thickness estimated to be -over two miles. - -From Huascatay westward and southward the Carboniferous is in part -displaced by secondary batholiths of granite, in part cut off or crowded -aside by igneous intrusions of later date, and in still larger part -buried under great masses of Tertiary volcanic material. Nevertheless, -it remains the dominating rock type over the whole stretch of country -from Huascatay to Huancarama. In the northwestern part of the Abancay -sheet its effect on the landscape may be observed in the knife-like -ridge extending from west to east just above Huambo. Above -Chuquibambilla it again outcrops, resting upon a thick resistant -quartzite of unknown age, Fig. 162. It is strongly developed about -Huadquirca and Antabamba and, still associated with a quartzite floor, -it finally disappears under the lavas of the great volcanic field on the -western border of the Andes. Figs. 141 and 142 show its relation to the -invading granite batholiths and Fig. 162 shows further structural -features as developed about Antabamba where the great volcanic field of -the Maritime Cordillera begins. - -[Illustration: FIG. 161--Types of deformation north of Lambrama near -Sotospampa. A dark basaltic rock has invaded both granite-gneiss and -slate. Sills and dikes occur in great numbers. The topographic -depression in the profile is the Lambrama Valley. See the Lambrama -Quadrangle.] - -Both the enormous thickness of the Carboniferous limestone series and -the absence of clastic members over great areas in the upper portion of -the series prove the widespread extent of the Carboniferous seas and -their former occurrence in large interlimestone tracts from which they -have since been eroded. At Puquiura they extend far over the schist, in -fact almost completely conceal it; at Pasaje they formerly covered the -mica-schists extensively, their erosion in both cases being conditioned -by the pronounced uplift and marginal deformation which accompanied the -development of the Vilcapampa batholith. - -[Illustration: FIG. 162--Sketch sections at Antabamba to show (a) -deformed limestones on the upper edge of the geologic map, Fig. 163 A; -and (b) the structural relations of limestone and quartzite. See also -Fig. 163.] - -The degree of deformation of the Carboniferous sediments varies between -simple uplift through moderate folding and complex disturbances -resulting in nearly vertical attitudes. The simplest structures are -represented at Pasaje, where the uplift of the intruded schists, -marginal to the Vilcapampa batholith, has produced an enormous -monoclinal fold exposing the entire section from basal conglomerates and -sandstones to the thickest limestone. Above Chuquibambilla the -limestones have been uplifted and very gently folded by the invasion of -granite associated with the main batholith and several satellitic -batholiths of limited extent. A higher degree of complexity is shown at -Pampaconas (Fig. 141), where the main monoclinal fold is traversed -almost at right angles by secondary folds of great amplitude. The -limestones are there carried to the limit of the winter snows almost at -the summit of the Cordillera. The crest of each secondary anticline -rises to form a group of conspicuous peaks and tabular ridges. Higher in -the section, as at Puquiura, the sandstones are thrown into a series of -huge anticlines and synclines, apparently by the marginal compression -brought about at the time of the intrusion of the granite core of the -range. At Pongo de Mainique the whole of the visible Carboniferous is -practically vertical, and is cut off by a great fault marking the abrupt -eastern border of the Cordillera. - -[Illustration: FIG. 163--Geologic sketch section to show the relation of -the volcanic flows of Fig. 164 to the sandstones and quartzites -beneath.] - -It is noteworthy that the farther east the Carboniferous extends the -more dominantly marine it becomes, though marine beds of great thickness -constitute a large part of the series in whatever location. From -Huascatay westward the limestones become more and more argillaceous, and -finally give way altogether to an enormous thickness of shales, -sandstones, and thin conglomerates. These were observed to extend with -strong inclination westward out of the region studied and into and under -the volcanoes crowning the western border of the Cordillera. Along the -line of traverse opportunity was not afforded for further study of this -aspect of the series, since our route led generally along the strike -rather than along the dip of the beds. It is interesting to note, -however, that these observations as to the increasing amounts of clastic -material in a westward direction were afterwards confirmed by Señor José -Bravo, the Director of the Bureau of Mines at Lima, who had found -Carboniferous land plants in shales at Pacasmayo, the only fossils of -their kind found in Peru. Formerly it had been supposed that non-marine -Carboniferous was not represented in Peru. From the varied nature of the -flora, the great thickness of the shales in which the specimens were -collected, and the fact that the dominantly marine Carboniferous -elsewhere in Peru is of great extent, it is concluded that the land upon -which the plants grew had a considerable area and probably extended far -west of the present coast line. Since its emergence it has passed -through several orogenic movements. These have resulted in the uplift of -the marine portion of the Carboniferous, while the terrestrial deposits -seem to have all but disappeared in the down-sunken blocks of the ocean -floor, west of the great fault developed along the margin of the -Cordillera. The following figures are graphic representations of this -hypothesis. - -[Illustration: FIG. 164--Geologic sketch map and section, Antabamba -region. The Antabamba River has cut through almost the entire series of -bedded strata]. - -[Illustration: FIG. 165--The upper diagram (A) represents the -hypothetical distribution of land and sea during the Carboniferous -Period, as inferred from the present distribution and character of -Carboniferous limestones and slates. The lower diagram (B) represents -the present relief. The dotted line at the left of the two diagrams -connects identical points. The fragmentation of the former continental -border is believed to have left only a small portion of a former coastal -chain and to have been contemporaneous with the development of ocean -abysses near the present shore.] - -The wide distribution of the Carboniferous sediments and especially the -limestones, together with the uniformity of the fossil faunas, makes it -certain that the sea extended entirely across the region now occupied -by the Andes. However, from the relation of the Carboniferous to the -basal schists, and the most conservative extension of the known -Carboniferous, it may be inferred that the Carboniferous sea did not -completely cover the entire area but was broken here and there by island -masses in the form of an elongated archipelago. The presence of land -plants in the Carboniferous of Pisco warrants the conclusion that a -second island mass, possibly an island chain parallel to the first, -extended along and west of the present shore. - - -CRETACEOUS - -The Cretaceous formations are of very limited extent in the belt of -country under consideration, in spite of their generally wide -distribution in Peru. They are exposed distinctly only on the western -border of the Cordillera and in special relations. In the gorge of -Cotahuasi, over seven thousand feet deep, about two thousand feet of -Cretaceous limestones are exposed. The series includes only a very -resistant blue limestone and terminates abruptly along a well-marked and -highly irregular erosion surface covered by almost a mile of volcanic -material, chiefly lava flows. The character of the bottom of the section -is likewise unknown, since it lies apparently far below the present -level of erosion. - -[Illustration: FIG. 166--Geologic sketch map and cross-section in the -Cotahuasi Canyon at Cotahuasi. With a slight gap this figure continues -Fig. 167 to the left. The section represents a spur of the main plateau -about 1,500 feet high in the center of the map.] - -The Cretaceous limestones of the Cotahuasi Canyon are everywhere greatly -and irregularly disturbed. Typical conditions are represented in the -maps and sections, Figs. 166 and 167. They are penetrated and tilted by -igneous masses, apparently the feeders of the great lava sheets that -form the western summit of the Cordillera. From the restricted -development of the limestones along a western border zone it might be -inferred that they represent a very limited marine invasion. It is -certainly clear that great deformative movements were in progress from -at least late Palæozoic time since all the Palæozoic deposits are broken -abruptly down in this direction, and, except for such isolated -occurrences as the land Carboniferous at Pacasmayo, are not found -anywhere in the coastal region today. The Cretaceous is not only limited -within a relatively narrow shore zone, but also, like the Palæozoic, it -is broken down toward the west, not reappearing from beneath the -Tertiary cover of the desert region or upon the granite-gneisses that -form the foundation for all the known sedimentary strata of the -immediate coast. - -[Illustration: FIG. 167--Geologic sketch map and cross-section in the -Cotahuasi Canyon at Taurisma, above Cotahuasi. The relations of -limestone and lava flows in the center of the map and on a spur top near -the canyon floor. Thousands of feet of lava extend upward from the flows -that cap the limestone.] - -From these considerations I think we have a strong suggestion of the -geologic date assignable to the development of the great fault that is -the most strongly marked structural and physiographic feature of the -west coast of South America. Since the development of this fault is so -intimately related to the origin of the Pacific Ocean basin its study is -of special importance. The points of chief interest may be summarized as -follows: - -(1) The character of the land Carboniferous implies a much greater -extent of the land than is now visible. - -(2) The progressive coarsening of the Carboniferous deposits westward -and their land derivation, together with the great thickness of the -series, point to an elevated land mass in process of erosion west of -the series as a whole, that is west of the present coast. - -(3) The restricted development of the Cretaceous seas upon the western -border of the Carboniferous, and the still more restricted development -of the Tertiary deposits between the mountains and the present coast, -point to increasing definition of the submarine scarp through the -Mesozoic and the Tertiary. - -(4) The Tertiary deposits are all clearly derived from the present -mountains and have been washed seaward down slopes with geographic -relations approximately like those of the present. - -(5) From the great width, deep dissection, and subsequent burial of the -Tertiary terraces of the coast, it is clear that the greater part of the -adjustment of the crust to which the bordering ocean basin is due was -accomplished at least by mid-Tertiary time. - -[Illustration: FIG. 168--Composite structure section representing the -succession of rocks in the Urubamba Valley from Urubamba to Torontoy.] - -Aside from the fossiliferous limestones of known Cretaceous age there -have been referred to the Cretaceous certain red sandstones and shales -marked, especially in the central portions of the Cordillera, by the -presence of large amounts of salt and gypsum. These beds were at first -considered Permian, but Steinmann has since found at Potosà related and -similar formations with Cretaceous fossils. In this connection it is -also necessary to add that the great red sandstone series forming the -eastern border of the Andes in Bolivia is of uncertain age and has -likewise been referred to the Cretaceous, though the matter of its age -has not yet been definitely determined. In 1913 I found it appearing in -northwestern Argentina in the Calchaquà Valley in a relation to the main -Andean mass, similar to that displayed farther north. It contains -fossils and its age was, therefore, readily determinable there.[53] - -In the Peruvian field the red beds of questionable age were not examined -in sufficient detail to make possible a definite age determination. They -occur in a great and only moderately disturbed series in the Anta basin -north of Cuzco, but are there not fossiliferous. The northeastern side -of the hill back of Puqura (of the Anta basin: to be distinguished from -Puquiura in the Vilcabamba Valley) is composed largely of rocks of this -class. In a few places their calcareous members have been weathered out -in such a manner as to show karst topography. Where they occur on the -well-drained brow of a bluff the caves are used in place of houses by -Indian farmers. The large and strikingly beautiful Lake Huaipo, ten -miles north of Anta, and several smaller, neighboring lakes, appear to -have originated in solution depressions formed in these beds. - -[Illustration: FIG. 169--The line of unconformity between the igneous -basement rocks (agglomerates at this point) and the quartzites and -sandstones of the Urubamba Valley, between the town of Urubamba and -Ollantaytambo.] - -[Illustration: FIG. 170--The inclined lower and horizontal upper -sandstone on the southeastern wall of the Majes Valley at Hacienda -Cantas. The section is a half-mile high.] - -The structural relation of the red sandstone series to the older rocks -is well displayed about half-way between Urubamba and Ollantaytambo in -the deep Urubamba Valley. The basal rocks are slaty schist and granite -succeeded by agglomerates and basalt porphyries upon whose eroded -surfaces (Fig. 169) are gray to yellow cross-bedded sandstones. Within a -few hundred feet of the unconformity gypsum deposits begin to appear and -increase in number to such an extent that the resulting soil is in -places rendered worthless. Copper-stained bands are also common near the -bottom of the series, but these are confined to the lower beds. Higher -up in the section, for example, just above the gorge between Urubamba -and Ollantaytambo, even-bedded sandstones occur whose most prominent -characteristic is the regular succession of coarse and fine sandstone -beds. Such alternations of character in sedimentary rocks are commonly -marked by alternating shales and sandstones, but in this locality shales -are practically absent. Toward the top of the section gypsum deposits -again appear first as beds and later, as in the case of the hill-slope -on the southern shore of Lake Huaipo, as veins and irregular masses of -gypsum. The top of the deformed Cretaceous (?) is eroded and again -covered unconformably by practically flat-lying Tertiary deposits. - - -TERTIARY - -The Tertiary deposits of the region under discussion are limited to -three regions: (1) the extreme eastern border of the main Cordillera, -(2) intermontane basins, the largest and most important of which are (a) -the Cuzco basin and (b) the Titicaca-Poopó basin on the -Peruvian-Bolivian frontier, and (3) in the west-coast desert and in -places upon the huge terraces that form a striking feature of the -topography of the coast of Peru. - -It has already been pointed out that the eastern border of the -Cordillera is marked by a fault of great but undetermined throw, whose -topographic importance may be estimated from the fact that even after -prolonged erosion it stands nearly four thousand feet high. Cross-bedded -and ripple-marked features and small lenses of conglomerate are common. -The beds now dip at an angle approximately 20° to 50° northward at the -base of the scarp, but have decreasing dip as they extend farther north -and east. It is noteworthy that the deposits become distinctly -conglomeratic as flatter dips are attained, and that there seems to have -been a steady accumulation of detrital material from the mountains for a -long period, since the deposits pass in unbroken succession from the -highly indurated and massive beds of the mountain base to loose -conglomerates that now weather down much like an ordinary gravel bank. -In a few places just below the mouth of the Ticumpinea, logs about six -inches in diameter were observed embeded in the deposits, but these -belong distinctly to the upper horizons. - -The border deposits, though they vary in dip from nearly flat to 50°, -are everywhere somewhat inclined and now lie up to several hundred feet -above the level of the Urubamba River. Their upper surface is moderately -dissected, the degree of dissection being most pronounced where the dips -are steepest and the height greatest. In fact, the attitude of the -deposits and their progressive change in character point toward, if they -do not actually prove, the steady and progressive character of the beds -first deposited and their erosion and redeposition in beds now higher in -the series. - -Upon the eroded upper surfaces of the inclined border deposits, gravel -beds have been laid which, from evidence discussed in a later paragraph, -are without doubt referable to the Pleistocene. These in turn are now -dissected. They do not extend to the highest summits of the deformed -beds but are confined, so far as observations have gone, to elevations -about one hundred feet above the river. From the evidence that the -overlying horizontal beds are Pleistocene, the thick, inclined beds are -referred to Tertiary age, though they are nowhere fossiliferous. - -Observations along the Urubamba River were extended as far northward as -the mouth of the Timpia, one of the larger tributaries. Upon returning -from this point by land a wide view of the country was gained from the -four-thousand-foot ridge of vertical Carboniferous limestone, in which -it appeared that low and irregular strike ridges continue the features -of the Tertiary displayed along the mountain front far northward as well -as eastward, to a point where the higher ridges and low mountains of -older rock again appear--the last outliers of the Andean system in Peru. -Unfortunately time enough was not available for an extension of the trip -to these localities whose geologic characters still remain entirely -unknown. From the topographic aspects of the country, it is, however, -reasonably certain that the whole intervening depression between these -outlying ranges and the border of the main Cordillera, is filled with -inclined and now dissected and partly covered Tertiary strata. The -elevation of the upper surface does not, however, remain the same; it -appears to decrease steadily and the youngest Tertiary strata disappear -from view below the sediments of either the Pleistocene or the present -river gravels. In the more central parts of the depression occupied by -the Urubamba Valley, only knobs or ridges project here and there above -the general level. - - -_The Coastal Tertiary_ - -The Tertiary deposits of the Peruvian desert region southwest of the -Andes have many special features related to coastal deformation, changes -of climate, and great Andean uplifts. They lie between the west coast of -Peru at Camaná and the high, lava-covered country that forms the western -border of the Andes and in places are over a mile thick. They are -non-fossiliferous, cross-bedded, ripple-marked, and have abundant lenses -of conglomerate of all sizes. The beds rest upon an irregular floor -developed upon a varied mass of rocks. In some places the basement -consists of old strata, strongly deformed and eroded. In other places it -consists of a granite allied in character and probably in origin with -the old granite-gneiss of the Coast Range toward the west. Elsewhere the -rock is lava, evidently the earliest in the great series of volcanic -flows that form this portion of the Andes. - -The deposits on the western border of the Andes are excellently exposed -in the Majes Valley, one of the most famous in Peru, though its fame -rests rather upon the excellence and abundance of its vineyards and -wines than its splendid geologic sections. Its head lies near the base -of the snow-capped peaks of Coropuna; its mouth is at Camaná on the -Pacific, a hundred miles north of Mollendo. It is both narrow and deep; -one may ride across its floor anywhere in a half hour. In places it is a -narrow canyon. Above Cantas it is sunk nearly a mile below the level of -the desert upland through which it flows. Along its borders are exposed -basal granites, old sedimentaries, and lavas; inter-bedded with it are -other lavas that lie near the base of the great volcanic series; through -it still project the old granites of the Coast Range; and upon it have -been accumulated additional volcanic rocks, wind-blown deposits, and, -finally, coarse wash formed during the glacial period. From both the -variety of the formations, the small amount of marginal dissection, and -the excellent exposures made possible by the deep erosion and desert -climate, the Majes Valley is one of the most profitable places in Peru -for physiographic and geologic study. - -[Illustration: FIG. 171--Generalized sketch section to show the -structural relations of the Maritime Cordillera, the desert pampas, and -the Coast Range.] - -The most complete succession of strata (Tertiary) occurs just below -Cantas on the trail to Jaguey (Fig. 171). Upon a floor of -granite-gneiss, and alternating beds of quartzite and shale belonging to -an older series, are deposited heavy beds of red sandstone with many -conglomerate lenses. The sandstone strata are measurably deformed and -their upper surfaces moderately dissected. Upon them have been deposited -unconformably a thicker series of deposits, conglomerates, sandstones, -and finer wind-blown material. The basal conglomerate is very -coarse--much like beach material in both structure and composition, and -similar to that along and south of the present coast at Camaná. Higher -in the section the material is prevailingly sandy and is deposited in -regular beds from a few inches to a few feet in thickness. Near the top -of the section are a few hundred feet of strata chiefly wind deposited. -Unconformably overlying the whole series and in sharp contrast to the -fine wind-blown stuff below it, is a third series of coarse deposits -about five hundred feet thick. The topmost material, that forming the -surface of the desert upland, consists of wind-blown sand now shifted by -the wind and gathered into sand dunes or irregular drifts, banks of -white earth, “tierra blanca,†and a pebble pavement a few inches thick. - -If the main facts of the above section are now summarized they will -facilitate an understanding of other sections about to be described, -inasmuch as the summary will in a measure anticipate our conclusions -concerning the origin of the deposits and their subsequent history. The -sediments in the Majes Valley between Cantas and Jaguey consist of three -series separated by two unconformities. The lowermost series is evenly -bedded and rather uniform in composition and topographic expression, -standing forth in huge cliffs several hundred feet high on the eastern -side of the valley. This lower series is overlain by a second series, -which consists of coarse conglomerate grading into sand and ultimately -into very fine fluffy wind-deposited sands and silts. The lower series -is much more deformed than the upper, showing that the deforming -movements of later geologic times have been much less intense than the -earlier, as if there had been a fading out or weakening of the deforming -agents. Finally there is a third series several hundred feet thick which -forms the top of the section. - -[Illustration: FIG. 172--Geologic relations of Coast Range, desert -deposits, and Maritime Cordillera at Moquegua, Peru. After G. I. Adams; -Bol. de Minas del Perú, Vol. 2, No. 4, 1906, p. 20.] - -[Illustration: FIG. 173--Sketch section to show structural details on -the walls of the Majes Valley near Aplao, looking south.] - -Three other sections may now be examined, one immediately below Cantas, -one just above, and one opposite Aplao. The section below Cantas is -shown in Fig. 173, and indicates a lower series of red sandstones -crossed by vertical faults and unconformably overlain by nearly -horizontal conglomerates, sandstones, etc., and the whole faulted again -with an inclined fault having a throw of nearly 25°. A white to gray -sandstone unconformably overlying the red sandstone is shown -interpolated between the lowermost and uppermost series, the only -example of its kind, however. No important differences in -lithographical character may be noted between these and the beds of the -preceding section. - -Again just above Cantas on the east side of the valley is a clean -section exposing about two thousand feet of strata in a half mile of -distance. The foundation rocks are old quartzites and shales in -regularly alternating beds. Upon their uneven upper surfaces are several -thousand feet of red sandstones and conglomerates, which are both folded -and faulted with the underlying quartzites. Above the red sandstones is -a thick series of gray sandstones and silts which makes the top of the -section and unconformably overlies the earlier series. - -A similar succession of strata was observed at Aplao, still farther up -the Majes Valley, Fig. 174. A greatly deformed and metamorphosed older -series is unconformably overlaid by a great thickness of younger strata. -The younger strata may be again divided into two series, a lower series -consisting chiefly of red sandstones and an upper consisting of gray to -yellow, and only locally red sands of finer texture and more uniform -composition. The two are separated by an erosion surface and only the -upper series is tilted regionally seaward with faint local deformation; -the lower series is both folded and faulted with overthrusts aggregating -several thousand feet of vertical and a half mile of horizontal -displacement. - -[Illustration: FIG. 174--The structural relations of the strata on the -border of the Majes Valley at Aplao, looking west. Field sketch from -opposite side of valley. Height of section about 3,000 feet; length -about ten miles.] - -The above sections all lie on the eastern side of the Majes Valley. From -the upper edge of the valley extensive views were gained of the strata -on the opposite side, and two sections, though they were not examined at -close range, are at least worth comparing with those already given. From -the narrows below Cantas the structure appears as in Figs. 175-176, and -shows a deforming movement succeeded by erosion in a lower series. The -upper series of sedimentary rock has suffered but slight deformation. A -still more highly deformed basal series occurs on the right of the -section, presumably the older quartzites. At Huancarqui, opposite Aplao, -an extensive view was gained of the western side of the valley, but the -lower Tertiary seems not to be represented here, as the upper undeformed -series rests unconformably upon a tilted series of quartzites and -slates. Farther up the Cantas valley (an hour’s ride above Aplao) the -Tertiary rests upon volcanic flows or older quartzites or the -granite-gneiss exposed here and there along the valley floor. - -[Illustration: FIG. 175--Sketch section to show the structural details -of the strata on the south wall of the Majes Valley near Cantas. The -section is two miles long.] - -[Illustration: FIG. 176--Composite geologic section to show the -structural relations of the rocks on the western border of the Maritime -Cordillera. The inclined strata at the right bottom represent older -rocks; in places igneous, in other places sedimentary.] - -In no part of the sedimentaries in the Majes Valley were fossils found, -save in the now uplifted and dissected sands that overlie the upraised -terraces along the coast immediately south of Camaná and also back of -Mollendo. Like similar coastal deposits elsewhere along the Peruvian -littoral, the terrace sands are of Pliocene or early Pleistocene age. -The age of the deposits back of the Coast Range is clearly greater than -that of the coastal deposits, (1) since they involve two unconformities, -a mile or more of sediments, and now stand at least a thousand feet -above the highest Pliocene (or Pleistocene) in the Camaná Valley, and -(2) because the erosion history of the interior sediments may be -correlated with the physiographic history of the coastal terraces and -the correlation shows that uplift and dissection of the terraces and of -the interior deposits went hand in hand, and that the deposits on the -terraces may similarly be correlated with alluvial deposits in the -valley. - -We shall now see what further ground there is for the determination of -the age of these sediments. Just below Chuquibamba, where they first -appear, the sediments rest upon a floor of volcanic and older rock -belonging to the great field now known from evidence in many localities -to have been formed in the early Tertiary, and here known to be -post-Cretaceous from the relations between Cretaceous limestones and -volcanics in the Cotahuasi Valley (see p. 247). Although volcanic flows -were noted interbedded with the desert deposits, these are few in -number, insignificant in volume, and belong to the top of the volcanic -series. The same may be said of the volcanic flows that locally overlie -the desert deposits. We have then definite proof that the sandstones, -conglomerates, and related formations of the Majes Valley and bordering -uplands are older than the Pliocene or early Pleistocene and younger -than the Cretaceous and the older Tertiary lavas. Hence it can scarcely -be doubted that they represent a considerable part of the Tertiary -period, especially in view of the long periods of accumulation which the -thick sediments represent, and the additional long periods represented -by the two well-marked unconformities between the three principal groups -of strata. - -If we now trace the physical history of the region we have first of all -a deep depression between the granite range along the coast and the -western flank of the Andes. Here and there, as in the Vitor, the Majes, -and other valleys, there were gaps through the Coast Range. Nowhere did -the relief of the coastal chain exceed 5,000 feet. The depression had -been partly filled in early geologic (probably early Paleozoic) time by -sediments later deformed and metamorphosed so that they are now -quartzites and shales. The greater resistance of the granite of the -Coast Range resulted in superior relief, while the older deformed -sedimentaries were deeply eroded, with the result that by the beginning -of the Tertiary the basin quality of the depression was again -emphasized. All these facts are expressed graphically in Fig. 171. On -the western flanks of the granite range no corresponding sedimentary -deposits are found in this latitude. The sea thus appears to have stood -farther west of the Coast Range in Paleozoic times than at present. - -[Illustration: FIG. 177--Composite structure section at Aplao.] - -For the later history it is necessary to assemble the various Tertiary -sections described on the preceding pages. First of all we recognize -three quite distinct types of accumulations, for which we shall have to -postulate three sets of conditions and possibly three separate agents. -The first or lowermost consists of even-bedded deposits of red and gray -sandstones, the former color predominating. The material is in general -well-sorted save locally, where lenses and even thin beds of -conglomerate have been developed. There is, however, about the whole -series a uniformity and an orderliness in striking contrast to the -coarse, cross-bedded, and irregular material above the unconformity. On -their northeastern or inner margin the sandstones are notably coarser -and thicker, a natural result of proximity to the mountains, the source -of the material. The general absence of wind-blown deposits is marked; -these occur entirely along the eastern and northern portions of the -deposits and are recognized (1) by their peculiar cross-bedding, and (2) -by the fact that the cross-bedding is directed northeastward in a -direction contrary to the regional dip of the series, a condition -attributable to the strong sea breezes that prevail every afternoon in -this latitude. - -The main body of the material is such as might be deposited on the wide -flood plains of piedmont streams during a period of prolonged erosion -on surrounding highlands that served as the feeding grounds of the -streams. The alternations in the character of the deposits, alternations -which, in a general view, give a banded appearance to the rock, are -produced by successions of beds of fine and coarse material, though all -of it is sandstone. Such successions are probably to be correlated with -seasonal changes in the volume and load of the depositing streams. - -To gain an idea of the conditions of deposition we may take the -character of the sediments as described above, and from them draw -deductions as to the agents concerned and the manner of their action. - -We may also apply to the area the conclusions drawn from the study of -similar deposits now in process of formation. We have between the coast -ranges of northern Chile and the western flanks of the Cordillera -Sillilica, probably the best example of piedmont accumulation in a dry -climate that the west coast of South America affords. - -Along the inner edge of the Desert of Tarapacá, roughly between the -towns of Tarapacá and Quillagua, Chile, the piedmont gravels, sands, -silts, and muds extend for over a hundred miles, flanking the western -Andes and forming a transition belt between these mountains and the -interior basins of the coast desert. The silts and muds constitute the -outer fringe of the piedmont and are interrupted here and there where -sands are blown upon them from the higher portions of the piedmont, or -from the desert mountains and plains on the seaward side. Practically no -rain falls upon the greater part of the desert and the only water it -receives is that borne to it by the piedmont streams in the early -summer, from the rains and melted snows of the high plateau and -mountains to the eastward. These temporary streams spread upon the outer -edge of the piedmont a wide sheet of mud and silt which then dries and -becomes cracked, the curled and warped plates retaining their character -until the next wet season or until covered with wind-blown sand. The -wind-driven sand fills the cracks in the muds and is even drifted under -the edges of the upcurled plates, filling the spaces completely. Over -this combined fluvial and æolian deposit is spread the next layer of -mud, which frequently is less extensive than the earlier deposits, thus -giving abundant opportunity for the observation of the exact manner of -burial of the older sand-covered stratum. - -Now while the alternations are as marked in Peru as in Chile, it is -noteworthy that the Tertiary material in Peru is not only coarse -throughout, even to the farthest limits of the piedmont, but also that -the alternating beds are thick. Moreover, there are only the most feeble -evidences of wind action in the lowermost Tertiary series. I was -prepared to find curled plates, wind-blown sands, and muds and silts, -but they are almost wholly absent. It is, therefore, concluded that the -dryness was far less extreme than it is today and that full streams of -great competency flowed vigorously down from the mountains and carried -their loads to the inner border of the Coast Range and in places to the -sea. - -The fact that the finer material is _sandy_, not clayey or silty, that -it almost equals in thickness the coarser layers, and that its -distribution appears to be co-extensive with the coarser, warrants the -conclusion that it too was deposited by competent streams of a type far -different from the withering streams associated with piedmont deposits -in a thoroughly arid climate like that of today. Both in the second -Tertiary series and on the present surface are such clear examples of -deposits made in a drier climate as to leave little doubt that the -earliest of the Tertiary strata of the Majes Valley were deposited in a -time of far greater rainfall than the present. It is further concluded -that there was increasing dryness, as shown by hundreds of feet of -wind-blown sand near the top of the section. But the growing dryness was -interrupted by at least one period of greater precipitation. Since that -time there has been a return to the dry climate of a former epoch. - -Uplift and erosion of the earliest of the Tertiary deposits of the Majes -Valley is indicated in two ways: (1) by the deformed character of the -beds, and (2) by the ensuing coarse deposits which were derived from the -invigorated streams. Without strong deformations it would not be -possible to assign the increased erosion so confidently to uplift; with -the coarse deposits that succeed the unconformity we have evidence of -accumulation under conditions of renewed uplift in the mountains and of -full streams competent to remove the increasing load. - -It is in the character of the sediments toward the top of the Tertiary -that we have the clearest evidence of progressive desiccation of the -climate of the region. The amount of wind-blown material steadily -increases and the uppermost five hundred feet is composed predominantly, -and in places exclusively, of this material. The evidences of wind -action lie chiefly in the fine (in places fluffy) nature of the -deposits, their uniform character, and in the tangency of the layers -with respect to the surface on which they were deposited. There are -three diagnostic structural features of great importance: the very steep -dip of the fine laminae; the peculiar and harmonious blending of their -contacts; the manner in which the highly inclined laminae cut off and -succeed each other, whereby quite bewildering changes in the direction -of dip of the inclined beds are brought about on any exposed plane. Some -of these features require further discussion. - -It is well known that the front of a sand dune generally consists of -sand deposited on a slope inclined at the angle of repose, say between -30° and 35°, and rolled into place up the long back slope of the dune by -the wind. It has not, however, been generally recognized that the angle -of repose may be exceeded (a) when there exists a strong back eddy or -(b) when the wind blows violently and for a short time in the opposite -direction. In either case sand is carried up the short steep slope of -the dune front and accumulated at an angle not infrequently running up -to 43° and 48° and locally, and under the most favorable circumstances, -in excess of 50°. The conditions under which these steep angles are -attained are undoubtedly not universal, but they can be found in some -parts of almost any desert in the world. They appear not to be present -where the sand grains are of uniform size throughout, since that leads -to rolling. They are found rather where there is a certain limited -variation in size that promotes packing. Packing and the development of -steep slopes are also facilitated in parts of the coastal desert of Peru -by a cloud canopy that hangs over the desert in the early morning, that -in the most favorable places moistens even the dune surfaces and that -has least penetration on the steep semi-protected dune fronts. Sand -later blown up the dune front or rolled down from the dune crest is -encouraged to remain near the cornice on an abnormally steep slope by -the attraction which the slightly moister sand has for the dry grains -blown against it. Since dunes travel and since their front layers, -formed on steep slopes, are cut off to the level of the surface in the -rear of the dune, it follows that the steepest dips in exposed sections -are almost always less than those in existing dunes. Exceptions to the -rule will be noted in filled hollows not re-excavated until deeply -covered by wind-blown material. These, re-exposed at the end of a long -period of wind accumulation, may exhibit even the maximum dips of the -dune cornices. Such will be conspicuously the case in sections in -aggraded desert deposits. On the border of the Majes Valley, from 400 to -500 feet of wind-accumulated deposits may be observed, representing a -long period of successive dune burials. - -The peculiar blending of the contact lines of dune laminae, related to -the tangency commonly noted in dune accumulations, is apparently due to -the fact that the wind does not require a graded surface to work on, but -blows uphill as well as down. It is present on both the back-slope and -the front-slope deposits. Its finest expression appears to be in -districts where the dune material was accumulated by a violent wind -whose effects the less powerful winds could not destroy. - -It is to the ability of the wind to transport material against, as well -as with, gravity, that we owe the third distinct quality of dune -material, the succession of flowing lines, in contrast to the succession -of now flat-lying now steeply inclined beds characteristic of -cross-bedded material deposited by water. One dune travels across the -face of the country only to be succeeded by another.[54] Even if wind -aggradation is in progress, the plain-like surface in the rear of a dune -may be excavated to the level of steeply inclined beds upon whose -truncated outcrop other inclined beds are laid, Fig. 178. The contrast -to these conditions in the case of aggradation by water is so clearly -and easily inferred that space will not be taken to point them out. It -is also true as a corollary to the above that the greater part of a body -of wind-drifted material will consist of cross-bedded layers, and not a -series of evenly divided and alternating flat-lying and cross-bedded -layers which result from deposition in active and variable currents of -water. - -The caution must of course be observed that wind action and water action -may alternate in a desert region, as already described in Tarapacá in -northern Chile, so that the whole of a deposit may exhibit an -alternation of cross-bedded and flat-lying layers; but the former only -are due to wind action, the latter to water action. - -Finally it may be noted that the sudden, frequent, and diversified dips -in the cross-bedding are peculiarly characteristic of wind action. -Although one sees in a given cross-section dips apparently directed only -toward the left or the right, excavation will supply a third dimension -from which the true dips may be either observed or calculated. These -show an almost infinite variety of directions of dip, even in restricted -areas, a condition due to the following causes: - -(1) the curved fronts of sand dunes, which produce dips concentric with -respect to a point and ranging through 180° of arc; (2) the irregular -character of sand dunes in many places, a condition due in turn to (a) -the changeful character of the strong wind (often not the prevailing -wind) to which the formation of the dunes is due, and (b) the influence -of the local topography upon wind directions within short distances or -upon winds of different directions in which a slight change in wind -direction is followed by a large change in the local currents; (3) the -fact that all combinations are possible between the erosion levels of -the wind in successive generations of dunes blown across a given area, -hence _any_ condition at a given level in a dune may be combined with -_any other_ condition of a succeeding dune; (4) variations in the sizes -of successive dunes will lead to further contrasts not only in the -scale of the features but also in the direction and amount of the dips. - -[Illustration: FIG. 178--Plan and cross-sections of superimposed sand -dunes of conventional outline. In the sections, dune _A_ is supposed to -have left only a small basal portion to be covered by dune _B_. In the -same way dune _C_ has advanced to cover both _A_ and _B_. The basal -portions that have remained are exaggerated vertically in order to -display the stratification. It is obviously not necessary that the dunes -should all be of the same size and shape and advancing in the same -direction in order to have the tangential relations here displayed. Nor -need the aggrading material be derived from true dunes. The results -would be the same in the case of sand _drifts_ with their associated -wind eddies. All bedded wind-blown deposits would have the same general -relations. No two successive deposits, no matter from what direction the -successive drifts or dunes travel, would exactly correspond in direction -and amount of dip.] - -Finally, we may note that a section of dune deposits has a distinctive -feature not exhibited by water deposits. If the foreset beds of a -cross-bedded water deposit be exposed in a plane parallel to the strike -of the beds, the beds will appear to be horizontal. They could not then -be distinguished from the truly horizontal beds above and below them. -But the conditions of wind deposition we have just noted, and chiefly -the facts expressed by Fig. 178, make it impossible to select a position -in which both tangency and irregular dips are not well developed in a -wind deposit. I believe that we have in the foregoing facts and -inferences a means for the definite separation of these two classes of -deposits. Difficulties will arise only when there is a quick succession -of wind and water action in time, or where the wind produces powerful -and persistent effects without the actual formation of dunes. - -The latest known deposits in the coastal region are found surmounting -the terrace tops along the coast between Camaná and Quilca, where they -form deposits several hundred feet thick in places. The age of these -deposits is determined by fossil evidence, and is of extraordinary -interest in the determination of the age of the great terraces upon -which they lie. They consist of alternating beds of coarse and fine -material, the coarser increasing in thickness and frequency toward the -bottom of the section. It is also near the bottom of the section that -fossils are now found; the higher members are locally saline and -throughout there is a marked inclination of the beds toward the present -shore. The deposits appear not to have been derived from the underlying -granite-gneiss. They are distributed most abundantly near the mouths of -the larger streams, as near the Vitor at Quilca, and the Majes at -Camaná. Elsewhere the terrace summit is swept clean of waste, except -where local clay deposits lie in the ravines, as back of Mollendo and -where “tierras blancas†have been accumulated by the wind. - -These coastal deposits were laid down upon a dissected terrace up to -five miles in width. The degree of dissection is variable, and depends -upon the relation of the through-flowing streams to the Coast Range. The -Vitor and the Majes have cut down through the Coast Range, and locally -removed the terrace; smaller streams rising on the flanks of the Coast -Range either die out near the foot of the range or cross it in deep and -narrow valleys. The present drainage on the seaward slopes of the Coast -Range is entirely ineffective in reaching the sea, as was seen in 1911, -the wettest season known on the coast in years and one of the wettest -probably ever observed on this coast by man. - -In consequence of their deposition on a terrace that ranges in elevation -from zero to 1,500 feet above sea level, the deposits of the coast are -very irregularly disposed. But in consequence of their great bulk they -have a rather smooth upper surface, gradation having been carried to the -point where the irregularities of the dissected terrace were smoothed -out. Their general uniformity is broken where streams cross them, or -where streams crossed them during the wetter Pleistocene. Their -elevation, several hundred feet above sea level, is responsible for the -deep dissection of their coastal margin, where great cliffs have been -cut. - - -PLEISTOCENE - -The broad regional uplift of the Peruvian Andes in late Tertiary and in -Pleistocene times carried their summits above the level of perpetual -snow. It is still an open question whether or not uplift was -sufficiently great in the early Pleistocene to be influenced by the -first glaciations of that period. As yet, there are evidences of only -two glacial invasions, and both are considered late events on account of -the freshness of their deposits and the related topographic forms. The -coarse deposits--nearly 500 feet thick--that form the top of the desert -section described above clearly indicate a wetter climate than prevailed -during the deposition of the several hundred feet of wind-blown deposits -beneath them. But if our interpretation be correct these deposits are of -late Tertiary age, and their character and position are taken to -indicate climatic changes in the Tertiary. They may have been the mild -precursors of the greater climatic changes of glacial times. Certain it -is that they are quite unlike the mass of the Tertiary deposits. On the -other hand they are separated from the deposits of known glacial age by -a time interval of great length--an epoch in which was cut a benched -canyon nearly a mile deep and three miles wide. They must, therefore, -have been formed when the Andes were thousands of feet lower and unable -to nourish glaciers. It was only after the succeeding uplifts had raised -the mountain crests well above the frost line that the records of -oscillating climates were left in erratic deposits, troughed valleys, -cliffed cirques and pinnacled divides. - -The glacial forms are chiefly at the top of the country; the glacial -deposits are chiefly in the deep valleys that were carved before the -colder climate set in. The rock waste ground up by the ice was only a -small part of that delivered to the streams in glacial times. Everywhere -the wetter climate resulted in the partial stripping of the residual -soil gathered upon the smooth mature slopes formed during the long -Tertiary cycle of erosion. This moving sheet of waste as well as the -rock fragments carried away from the glacier ends were strewn along the -valley floors, forming a deep alluvial fill. Thereby the canyon floors -were rendered habitable. - -In the chapters on human geography we have already called attention to -the importance of the U-shaped valleys carved by the glaciers. Their -floors are broad and relatively smooth. Their walls restrain the live -stock. They are sheltered though lofty. But all the human benefits -conferred by ice action are insignificant beside those due to the -general shedding of waste from the cold upper surfaces to the warm -levels of the valley floors. The alluvium-filled valleys are the seats -of dense populations. In the lowest of them tropical and sub-tropical -products are raised, like sugar-cane and cotton, in a soil that once lay -on the smooth upper slopes of mountain spurs or that was ground fine on -the bed of an Alpine glacier. - -[Illustration: FIG. 179--Snow fields on the summit of the Cordillera -Vilcapampa near Ollantaytambo. A huge glacier once lay in the steep -canyon in the background and descended to the notched terminal moraine -at the canyon mouth. In places the glacier was over a thousand feet -thick. From the terminal moraine an enormous alluvial fan extends -forward to the camera and to the opposite wall of the Urubamba Valley. -It is confluent with other fans of the same origin. See Fig. 180. In the -foreground are flowers, shrubs, and cacti. A few miles below Urubamba at -11,500 feet.] - -[Illustration: FIG. 180--Urubamba Valley between Ollantaytambo and -Torontoy, showing (1) more moderate upper slopes and steeper lower -slopes of the two-cycle mountain spurs; (2) the extensive alluvial -deposits of the valley, consisting chiefly of confluent alluvial fans -heading in the glaciated mountains on the left. See Fig. 179.] - -[Illustration: FIG. 181--Glacial features of the Central Ranges (see -Fig. 204). Huge lateral moraines built by ice streams tributary to the -main valley north of Chuquibambilla. That the tributaries persisted long -after the main valley became free of ice is shown by the descent of the -lateral moraines over the steep border of the main valley and down to -the floor of it.] - -The Pleistocene deposits fall into three well-defined groups: (1) -glacial accumulations at the valley heads, (2) alluvial deposits in -the valleys, and (3) lacustrine deposits formed on the floors of -temporary lakes in inclosed basins. Among these the most variable in -form and composition are the true glacier-laid deposits at the valley -heads. The most extensive are the fluvial deposits accumulated as valley -fill throughout the entire Andean realm. Though important enough in some -respects the lacustrine deposits are of small extent and of rather local -significance. Practically none of them fall within the field of the -present expedition; hence we shall describe only the first two classes. - -The most important glacial deposits were accumulated in the eastern part -of the Andes as a result of greater precipitation, a lower snowline, and -catchment basins of larger area. In the Cordillera Vilcapampa glaciers -once existed up to twelve and fifteen miles in length, and those several -miles long were numerous both here and throughout the higher portions of -the entire Cordillera, save in the belt of most intense volcanic action, -which coincides with the driest part of the Andes, where the glaciers -were either very short or wanting altogether. - -Since vigorous glacial action results in general in the cleaning out of -the valley heads, no deposits of consequence occur in these locations. -Down valley, however, glacial deposits occur in the form of terminal -moraines of recession and ground moraines. The general nature of these -deposits is now so well known that detailed description seems quite -unnecessary except in the case of unusual features. - -It is noteworthy that the moraines decrease in size up valley since each -valley had been largely cleaned out by ice action before the retreat of -the glacier began. Each lowermost terminal moraine is fronted by a great -mass of unsorted coarse bowldery material forming a fill in places -several hundred feet thick, as below Choquetira and in the Vilcapampa -Valley between Vilcabamba and Puquiura. This bowldery fill is quite -distinct from the long, gently inclined, and stratified valley train -below it, or the marked ridge-like moraine above it. It is in places a -good half mile in length. Its origin is believed to be due to an -overriding action beyond the last terminal moraine at a time when the -ice was well charged with débris, an overriding not marked by morainal -accumulations, chiefly because the ice did not maintain an extreme -position for a long period. - -In the vicinity of the terminal moraines the alluvial valley fill is -often so coarse and so unorganized as to look like till in the cut banks -along the streams, though its alluvial origin is always shown by the -topographic form. This characteristic is of special geologic interest -since the form may be concealed through deposition or destroyed by -erosion, and no condition but the structure remain to indicate the -manner of origin of the deposit. In such an event it would not be -possible to distinguish between alluvium and till. The gravity of the -distinction appears when it is known that such apparently unsorted -alluvium may extend for several miles forward of a terminal moraine, in -the shape of a widespreading alluvial fan apparently formed under -conditions of extremely rapid aggradation. I suppose it would not be -doubted in general that a section of such stony, bowldery, unsorted -material two miles long would have other than a glacial origin, yet such -may be the case. Indeed, if, as in the Urubamba Valley, a future section -should run parallel to the valley across the heads of a great series of -fans of similar composition, topographic form, and origin, it would be -possible to see many miles of such material. - -The depth of the alluvial valley fill due to tributary fan accumulation -depends upon both the amount of the material and the form of the valley. -Below Urubamba in the Urubamba Valley a fine series is displayed, as -shown in Fig. 180. The fans head in valleys extending up to snow-covered -summits upon whose flanks living glaciers are at work today. Their heads -are now crowned by terminal moraines and both moraines and alluvial fans -are in process of dissection. The height and extent of the moraines and -the alluvial fans are in rough proportion and in turn reflect the -height, elevation, and extent of the valley heads which served as fields -of nourishment for the Pleistocene glaciers. Where the fans were -deposited in narrow valleys the effect was to increase the thickness of -the deposits at the expense of their area, to dam the drainage lines or -displace them, and to so load the streams that they have not yet -cleared their beds after thousands of years of work under torrential -conditions. - -Below Urubamba the alluvial fans entering the main valley from the east -have pushed the river against its western valley wall, so that the river -flows on one side against rock and on the other against a hundred feet -of stratified material. In places, as at the head of the narrows on the -valley trail to Ollantaytambo, a flood plain has been formed in front of -the scarp cut into the alluvium, while the edge of the dissected -alluvial fans has been sculptured into erosion forms resembling -bad-lands topography. On the western side of the valley the alluvial -fans are very small, since they are due to purely local accumulations of -waste from the edge of the plateau. Glaciation has here displaced the -river. Its effects will long be felt in the disproportionate erosion of -the western wall of the valley. - -By far the most interesting of the deposits of glacial time are those -laid down on the valley floors in the form of an alluvial fill. Though -such deposits have greater thickness as a rule near the nourishing -moraines or bordering alluvial fans at the lower ends of the valleys, -they are everywhere important in amount, distinctive in topographic -form, and of amazingly wide extent. They reach far into and possibly -across the Amazon basin, they form a distinct though small piedmont -fringe along the eastern base of the Andes, and they are universal -throughout the Andean valleys. That a deposit of such volume--many times -greater than all the material accumulated in the form of high-level -alluvial fans or terminal moraines--should originate in a tropical land -in a region that suffered but limited Alpine glaciation vastly increases -its importance. - -[Illustration: FIG. 182--Dissected alluvial fans on the border of the -Urubamba Valley near Hacienda Chinche. A Characteristic feature of the -valleys of the Peruvian Andes below the zone of glaciation but within -the limits of its aggraditional effects. Through alluviation the valleys -and basins of the Andean Cordillera, and vast areas of the great Amazon -plains east of it, felt the effects of the glacial conditions of a past -age.] - -The fill is composed of both fine and coarse material laid down by water -in steep valley floors to a depth of many feet. It breaks the steep -slope of each valley, forming terraces with pronounced frontal scarps -facing the river. On the raw bluffs at the scarps made by the -encroaching stream good exposures are afforded. At Chinche in the -Urubamba Valley above Santa Ana, the material is both sand and clay with -an important amount of gravel laid down with steep valleyward -inclination and under torrential conditions; so that within a given bed -there may be an apparent absence of lamination. Almost identical -conditions are exhibited frequently along the railway to Cuzco in the -Vilcanota Valley. The material is mixed sand and gravel, here and there -running to a bowldery or stony mass where accessions have been received -from some source nearby. It is modified along its margin not only in -topographic form but also in composition by small tributary alluvial -fans, though these in general constitute but a small part of the total -mass. At Cotahuasi, Fig. 29, there is a remarkable fill at least four -hundred feet deep in many places where the river has exposed fine -sections. The depth of the fill is, however, not determined by the -height of the erosion bluffs cut into it, since the bed of the river is -made of the same material. The rock floor of the valley is probably at -least an additional hundred feet below the present level of the river. - -[Illustration: FIG. 183--Two-cycle slopes and alluvial fill between -Iluichihua and Chuquibambilla. The steep slopes on the inner valley -border are in many places vertical and rock cliffs are everywhere -abundant. Mature slopes have their greatest development here between -13,500 and 15,000 feet (4,110 to 4,570 m.). Steepest mature slopes run -from 15° to 21°. Least steep are the almost level spur summits. The -depths of the valley fill must be at least 300, and may possibly be 500 -feet. The break between valley fill and steep slopes is most pronounced -where the river runs along the valley wall or undercuts it; least -pronounced where alluvial fans spread out from the head of some ravine. -It is a bowldery, stony fill almost everywhere terraced and cultivated.] - -Similar conditions are well displayed at Huadquiña, where a fine series -of terraces at the lower end of the Torontoy Canyon break the descent of -the environing slopes; also in the Urubamba Valley below Rosalina, and -again at the edge of the mountains at the Pongo de Mainique. It is -exhibited most impressively in the Majes Valley, where the bordering -slopes appear to be buried knee-deep in waste, and where from any -reasonable downward extension of rock walls of the valley there would -appear to be at least a half mile of it. It is doubtful and indeed -improbable that the entire fill of the Majes Valley is glacial, for -during the Pliocene or early Pleistocene there was a submergence which -gave opportunity for the partial filling of the valley with non-glacial -alluvium, upon which the glacial deposits were laid as upon a flat and -extensive floor that gives an exaggerated impression of their depth. -However, the head of the Majes Valley contains at least six hundred feet -and probably as much as eight hundred feet of alluvium now in process of -dissection, whose coarse texture and position indicates an origin under -glacial conditions. The fact argues for the great thickness of the -alluvial material of the lower valley, even granting a floor of Pliocene -or early Pleistocene sediments. The best sections are to be found just -below Chuquibamba and again about halfway between that city and Aplao, -whereas the best display of the still even-floored parts of the valley -are between Aplao and Cantas, where the braided river still deposits -coarse gravels upon its wide flood plain. - - - - -CHAPTER XVI - -GLACIAL FEATURES - -THE SNOWLINE - - -South America is classical ground in the study of tropical snowlines. -The African mountains that reach above the snowline in the equatorial -belt--Ruwenzori, Kibo, and Kenia--have only been studied recently -because they are remote from the sea and surrounded by bamboo jungle and -heavy tropical forest. On the other hand, many of the tropical mountains -of South America lie so near the west coast as to be visible from it and -have been studied for over a hundred years. From the days of Humboldt -(1800) and Boussingault (1825) down to the present, observations in the -Andes have been made by an increasing number of scientific travelers. -The result is a large body of data upon which comparative studies may -now be profitably undertaken. - -Like scattered geographic observations of many other kinds, the earlier -studies on the snowline have increased in value with time, because the -snowline is a function of climatic elements that are subject to periodic -changes in intensity and cannot be understood by reference to a single -observation. Since the discovery of physical proofs of climatic changes -in short cycles, studies have been made to determine the direction and -rate of change of the snowline the world over, with some very striking -results. - -It has been found[55] that the changes run in cycles of from thirty to -thirty-five years in length and that the northern and southern -hemispheres appear to be in opposite phase. For example, since 1885 the -snowline in the southern hemisphere has been decreasing in elevation in -nine out of twelve cases by the average amount of nine hundred feet. -With but a single exception, the snowline in the northern hemisphere -has been rising since 1890 with an average increase of five hundred feet -in sixteen cases. To be sure, we must recognize that the observations -upon which these conclusions rest have unequal value, due both to -personal factors and to differences in instrumental methods, but that in -spite of these tendencies toward inequality they should agree in -establishing a general rise of the snowline in the northern hemisphere -and an opposite effect in the southern is of the highest significance. - -It must also be realized that snowline observations are altogether too -meager and scattered in view of the abundant opportunities for making -them, that they should be standardized, and that they must extend over a -much longer period before they attain their full value in problems in -climatic variations. Once the possible significance of snowline changes -is appreciated the number and accuracy of observations on the elevation -and local climatic relations of the snowline should rapidly increase. - -In 1907 I made a number of observations on the height of the snowline in -the Bolivian and Chilean Andes between latitudes 17° and 20° south, and -in 1911 extended the work northward into the Peruvian Andes along the -seventy-third meridian. It is proposed here to assemble these -observations and, upon comparison with published data, to make a few -interpretations. - -From Central Lagunas, Chile, I went northeastward via Pica and the -Huasco Basin to Llica, Bolivia, crossing the Sillilica Pass in May, -1907, at 15,750 feet (4,800 m.). Perpetual snow lay at an estimated -height of 2,000-2,500 feet above the pass or 18,000 feet (5,490 m.) -above the sea. Two weeks later the Huasco Basin, 14,050 feet (4,280 m.), -was covered a half-foot deep with snow and a continuous snow mantle -extended down to 13,000 feet. Light snows are reported from 12,000 feet, -but they remain a few hours only and are restricted to the height of -exceptionally severe winter seasons (June and early July). Three or four -distant snow-capped peaks were observed and estimates made of the -elevation of the snowline between the Cordillera Sillilica and Llica on -the eastern border of the Maritime Cordillera. All observations agreed -in giving an elevation much in excess of 17,000 feet. In general the -values run from 18,000 to 19,000 feet (5,490 to 5,790 m.). Though the -bases of these figures are estimates, it should be noted that a large -part of the trail lies between 14,000 and 16,000 feet, passing mountains -snow-free at least 2,000 to 3,000 feet higher, and that for general -comparisons they have a distinct value. - -In the Eastern Cordillera of Bolivia, snow was observed on the summit of -the Tunari group of peaks northwest of Cochabamba. Steinmann, who -visited the region in 1904, but did not reach the summit of the Tunari -group of peaks, concludes that the limit of perpetual snow should be -placed above the highest point, 17,300 (5,270 m.); but in July and -August, 1907, I saw a rather extensive snow cover over at least the -upper 1,000 feet, and what appeared to be a very small glacier. Certain -it is that the Cochabamba Indians bring clear blue ice from the Tunari -to the principal hotels, just as ice is brought to Cliza from the peaks -above Arani. On these grounds I am inclined to place the snowline at -17,000 feet (5,180 m.) near the eastern border of the Eastern -Cordillera, latitude 17° S. At 13,000 feet, in July, 1907, snow occurred -in patches only on the pass called Abre de Malaga, northeast of Colomi, -13,000 feet, and fell thickly while we were descending the northern -slopes toward Corral, so that in the early morning it extended to the -cold timber line at 10,000 feet. In a few hours, however, it had -vanished from all but the higher and the shadier situations. - -In the Vilcanota knot above the divide between the Titicaca and -Vilcanota hydrographic systems, the elevation of the snowline was -16,300+ feet (4,970 m.) in September, 1907. On the Cordillera Real of -Bolivia it is 17,000 to 17,500 feet on the northeast, but falls to -16,000 feet on the southwest above La Paz. In the first week of July, -1911, snow fell on the streets of Cuzco (11,000 feet) and remained for -over an hour. The heights north of San Geronimo (16,000 feet) miss the -limit of perpetual snow and are snow-covered only a few months each -year. - -In taking observations on the snowline along the seventy-third meridian -I was fortunate enough to have a topographer the heights of whose -stations enabled me to correct the readings of my aneroid barometer -whenever these were taken off the line of traverse. Furthermore, the -greater height of the passes--15,000 to 17,600 feet--brought me more -frequently above the snowline than had been the case in Bolivia and -Chile. More detailed observations were made, therefore, not only upon -the elevation of the snowline from range to range, but also upon the -degree of canting of the snowline on a given range. Studies were also -made on the effect of the outline of the valleys upon the extent of the -glaciers, the influence on the position of the snowline of mass -elevation, precipitation, and cloudiness. - -Snow first appears at 14,500 feet (4,320 m.) on the eastern flanks of -the Cordillera Vilcapampa, in 13° south latitude. East of this group of -ridges and peaks as far as the extreme eastern border of the mountain -belt, fifty miles distant, the elevations decrease rapidly to 10,000 -feet and lower, with snow remaining on exceptionally high peaks from a -few hours to a few months. In the winter season snow falls now and then -as low as 11,500 feet, as in the valley below Vilcabamba pueblo in early -September, 1911, though it vanishes like mist with the appearance of the -sun or the warm up-valley winds from the forest. Storms gather daily -about the mountain summits and replenish the perpetual snow above 15,000 -feet. In the first pass above Puquiura we encountered heavy snow banks -on the northeastern side a hundred feet below the pass (14,500 feet), -but on the southwestern or leeward side it is five hundred feet lower. -This distribution is explained by the lesser insolation on the -southwestern side, the immediate drifting of the clouds from the -windward to the leeward slopes, and to the mutual intensification of -cause and effect by topographic changes such as the extension of -collecting basins and the steeping of the slopes overlooking them with a -corresponding increase in the duration of shade. - -It is well known that with increase of elevation and therefore of the -rarity of the air there is less absorption of the sun’s radiant energy, -and a corresponding increase in the degree of insolation. It follows, -therefore, that at high altitudes the contrasts between sun and shade -temperatures will increase. Frankland[56] has shown that the increase -may run as high as 500 per cent between 100 to 10,000 feet above the -sea. I have noted a fall of temperature of 15° F. in six minutes, due to -the obscuring of the sun by cloud at an elevation of 16,000 feet above -Huichihua in the Central Ranges of Peru. Since the sun shines -approximately half the time in the snow-covered portions of the -mountains and since the tropical Andes are of necessity snow-covered -only at lofty elevations, this contrast between shade and sun -temperatures is by far the most powerful factor influencing differences -in elevation of the snowline in Peru. - -To the drifting of the fallen snow is commonly ascribed a large portion -of this contrast. I have yet to see any evidence of its action near the -snowline, though I have often observed it, especially under a high wind -in the early morning hours at considerable elevations above the -snowline, as at the summits of lofty peaks. It appears that the lower -ranges bearing but a limited amount of snow are not subject to drifting -because of the wetness of the snow, and the fact that it is compacted by -occasional rains and hail storms. Only the drier snow at higher -elevations and under stronger winds can be effectively dislodged. - -The effect of unequal distribution of precipitation on the windward and -leeward slopes of a mountain range is in general to depress the snowline -on the windward slopes where the greater amount falls, but this may be -offset in high altitudes by temperature contrasts as in the westward -trending Cordillera Vilcapampa, where north and south slopes are in -opposition. If the Cordillera Vilcapampa ran north and south we should -have the windward and leeward slopes equally exposed to the sun and the -snowline would lie at a lower elevation on the eastern side. Among all -the ranges the slopes have decreasing precipitation to the leeward, that -is, westerly. The second and third passes, between Arma and Choquetira, -are snow-free (though their elevations equal those of the first pass) -because they are to leeward of the border range, hence receive less -precipitation. The depressive effect of increased precipitation on the -snowline is represented by A-B, Fig. 184; in an individual range the -effect of heavier precipitation may be offset by temperature contrasts -between shady and sunny slopes, as shown by the line a-b in the same -figure. - -The degree of canting of the snowline on opposite slopes of the -Cordillera Vilcapampa varies between 5° and 12°, the higher value being -represented four hours southwest of Arma on the Choquetira trail, -looking northeast. A general view of the Cordillera looking east at this -point (Fig. 186), shows the appearance of the snowline as one looks -along the flanks of the range. In detail the snowline is further -complicated by topography and varying insolation, each spur having a -snow-clad and snow-free aspect as shown in the last figure. The degree -of difference on these minor slopes may even exceed the difference -between opposite aspects of the range in which they occur. - -[Illustration: FIG. 184--To illustrate the canting of the snowline. -_A-B_ is the snowline depressed toward the north (right) in response to -heavier precipitation. The line _a-b_ represents a depression in the -opposite direction due to the different degree of insolation on the -northern (sunny) and southern (shady) slopes.] - -To these diversifying influences must be added the effect of warm -up-valley winds that precede the regular afternoon snow squalls and that -melt the latest fall of snow to exceptionally high elevations on both -the valley floor and the spurs against which they impinge. The influence -of the warmer air current is notably confined to the heads of those -master valleys that run down the wind, as in the valley heading at the -first pass, Cordillera Vilcapampa, and at the heads of the many valleys -terminating at the passes of the Maritime Cordillera. Elsewhere the -winds are dissipated in complex systems of minor valleys and their -effect is too well distributed to be recognized. - -It is clear from the conditions of the problem as outlined on preceding -pages that the amount of canting may be expressed in feet of difference -of the snowline on opposite sides of a range or in degrees. The former -method has, heretofore, been employed. It is proposed that this method -should be abolished and degrees substituted, on the following grounds: -Let _A_ and _B_, Fig. 190, represent two mountain masses of unequal area -and unequal elevation. Let the opposite ends of the snowlines of both -figures lie 1,000 feet apart as between the windward and leeward sides -of a broad cordillera (A), or as between the relatively sunnier and -relatively shadier slopes of individual mountains or narrow ranges in -high latitudes or high altitudes (B). With increasing elevation there is -increasing contrast between temperatures in sunshine and in shade, hence -a greater degree of canting (B). Tending toward a still greater degree -of contrast is the effect of the differences in the amounts of snowy -precipitation, which are always more marked on an isolated and lofty -mountain summit than upon a broad mountain mass (1) because in the -former there is a very restricted area where snow may accumulate, and -(2) because with increase of elevation there is a rapid and differential -decrease in both the rate of adiabatic cooling and the amount of water -vapor; hence the snow-producing forces are more quickly dissipated. - -[Illustration: FIG. 185--Glacial features in the Peruvian Andes near -Arequipa. Sketched from a railway train, July, 1911. The horizontal -broken lines represent the lower limit of light snow during late June, -1911. There is a fine succession of moraines in U-shaped valleys in all -the mountains of the Arequipa region. _A_ represents a part of Chacchani -northwest of Arequipa; _B_ is looking south by east at the northwest end -of Chacchani near Pampa de Arrieros; _C_ also shows the northwest end of -Chacchani from a more distant point.] - -[Illustration: FIG. 186--Canted snowline in the Cordillera Vilcapampa -between Arma and Choquetira. Looking east from 13,500 feet.] - -[Illustration: FIG. 187--Glacial topography between Lambrama and -Antabamba in the Central Ranges. A recent fall of snow covers the -foreground. The glaciers are now almost extinct and their action is -confined to the deepening and steepening of the cirques at the valley -heads.] - -[Illustration: FIG. 188--Asymmetrical peaks in the Central Ranges -between Antabamba and Lambrama. The snow-filled hollows in the -photograph face away from the sun--that is, south--and have retained -snow since the glacial epoch; while the northern slopes are snow-free. -There is no true glacial ice and the continued cirque recession is due -to nivation.] - -[Illustration: FIG. 189--Glacial topography north of the divide on the -seventy-third meridian. Maritime Cordillera. Looking downstream at an -elevation of 16,500 feet (5,030 m.).] - -Furthermore, the leeward side of a lofty mountain not only receives much -less snow proportionally than the leeward side of a lower mountain, -but also loses it faster on account of the smaller extent of surface -upon which it is disposed and the proportionally larger extent of -counteractive, snow-free surface about it. Among the volcanoes of -Ecuador are many that show differences of 500 feet in snowline elevation -on windward and leeward (east) slopes and some, as for example -Chimborazo, that exhibit differences of 1,000 feet. The latter figure -also expresses the differences in the broad Cordillera Vilcapampa and in -the Maritime Cordillera, though the _rate_ of canting as expressed in -degrees is much greater in the case of the western mountains. - -[Illustration: FIG. 190--To illustrate the difference in the degree of -canting of the snowline on large and on small mountain masses.] - -The advantages of the proposed method of indicating the degree of -canting of the snowline lie in the possibility thus afforded of -ultimately separating and expressing quantitatively the various factors -that affect the position of the line. In the Cordillera Vilcapampa, for -example, the dominant canting force is the difference between sun and -shade temperatures, while in the volcanoes of Ecuador, where -_symmetrical volcanoes, almost on the equator, have equal insolation on -all aspects_ and the temperature contrasts are reduced to a minimum--the -differences are owing chiefly to varying exposure to the winds. The -elusive factors in the comparison are related to the differences in area -and in elevation. - -The value of arriving finally at close snowline analyses grows out of -(1) the possibility of snowline changes in short cycles and (2) -uncertainty of arriving by existing methods at the snowline of the -glacial period, whose importance is fundamental in refined physiographic -studies in glaciated regions with a complex topography. To show the -application of the latter point we shall now attempt to determine the -snowline of the glacial period in the belt of country along the route of -the Expedition. - -In the group of peaks shown in Fig. 188 between Lambrama and Antabamba, -the elevation of the snowline varies from 16,000 to 17,000 feet -(4,880-5,180 m.), depending on the topography and the exposure. The -determination of the limit of perpetual snow was here, as elsewhere -along the seventy-third meridian, based upon evidences of nivation. It -will be observed in Fig. 191 that just under the snow banks to the left -of the center are streams of rock waste which head in the snow. Their -size is roughly proportional to the size of the snow banks, and, -furthermore, they are not found on snow-free slopes. From these facts it -is concluded that they represent the waste products of snow erosion or -nivation, just as the hollows in which the snow lies represent the -topographic products of nivation. On account of the seasonal and annual -variation in precipitation and temperature--hence in the elevation of -the snowline--it is often difficult to make a correct snowline -observation based upon depth and _apparent_ permanence. Different -observers report great changes in the snowline in short intervals, -changes not explained by instrumental variations, since they are -referred to topographic features. It appears to be impossible to rely -upon present records for small changes possibly related to minor -climatic cycles because of a lack of standardization of observations. - -Nothing in the world seems simpler at first sight than an observation on -the elevation of the snowline. Yet it can be demonstrated that large -numbers of observers have merely noted the position of temporary snow. -It is strongly urged that evidences of nivation serve henceforth as -proof of permanent snow and that photographic records be kept for -comparison. In this way measurements of changes in the level of the -snowline may be accurately made and the snow cover used as a climatic -gauge. - -Farther west in the Maritime Cordillera, the snowline rises to 18,000 -feet on the northern slopes of the mountains and to 17,000 feet on the -southern slopes. The top of the pass above Cotahuasi, 17,600 feet (5,360 -m.), was snow-free in October, 1911, but the snow extended 500 feet -lower on the southern slope. The degree of canting is extraordinary at -this point, single volcanoes only 1,500 to 2,000 feet above the general -level and with bases but a few miles in circumference exhibit a thousand -feet of difference in the snowline upon northern and southern aspects. -This is to be attributed no less to the extreme elevation of the snow -(and, therefore, stronger contrasts of shade and sun temperatures) than -to the extreme aridity of the region and the high daytime temperatures. -The aridity is a factor, since heavy snowfall means a lengthening of the -period of precipitation in which a cloud cover shuts out the sun and a -shortening of the period of insolation and melting. - -Contrasts between shade and sun temperatures increase with altitude but -their effects also increase in _time_. Of two volcanoes of equal size -and both 20,000 feet above sea level, that one will show the greater -degree of canting that is longer exposed to the sun. The high daytime -temperature is a factor, since it tends to remove the thinnest snow, -which also falls in this case on the side receiving the greatest amount -of heat from the sun. The high daytime temperature is phenomenal in this -region, and is owing to the great extent of snow-free land at high -elevations and yet below the snowline, and to the general absence of -clouds and the thinness of vegetation. - -On approach to the western coast the snowline descends again to 17,500 -feet on Coropuna. There are three chief reasons for this condition. -First, the well-watered Majes Valley is deeply incised almost to the -foot of Coropuna, above Chuquibamba, and gives the daily strong sea -breeze easy access to the mountain. Second, the Coast Range is not only -low at the mouth of the Majes Valley, but also is cut squarely across by -the valley itself, so that heavy fogs and cloud sweep inland nightly and -at times completely cover both valley and desert for an hour after -sunrise. Although these yield no moisture to the desert or the valley -floor except such as is mechanically collected, yet they do increase the -precipitation upon the higher elevations at the valley head. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM DIRECTOR - -ANTABAMBA QUADRANGLE] - -A third factor is the size of Coropuna itself. The mountain is not a -simple volcano but a composite cone with five main summits reaching well -above the snowline, the highest to an elevation of 21,703 feet (6,615 -m.). It measures about 20 miles (32 km.) in circumference at the -snowline and 45 miles (72 km.) at its base (measuring at the foot of the -steeper portion), and stands upon a great tributary lava plateau from -15,000 to 17,000 feet above sea level. Compared with El Misti, at -Arequipa, its volume is three times as great, its height two thousand -feet more, and its access to ocean winds at least thirty per cent more -favorable. El Misti, 19,200 feet (5,855 m.) has snow down as far as -16,000 feet in the wet season and rarely to 14,000 feet, though by -sunset a fall of snow may almost disappear whose lower limit at sunrise -was 16,000 feet. Snow may accumulate several thousand feet below the -summit during the wet season, and in such quantities as to require -almost the whole of the ensuing dry season (March to December) for its -melting. Northward of El Misti is the massive and extended range, -Chachani, 20,000 feet (6,100 m.) high; on the opposite side is the -shorter range called Pichu-Pichu. Snow lies throughout the year on both -these ranges, but in exceptional seasons it nearly disappears from -Chachani and wholly disappears from Pichu-Pichu, so that the snowline -then rises to 20,000 feet. It is considered that the mean of a series of -years would give a value between 17,000 and 18,000 feet for the snowline -on all the great mountains of the Arequipa region.[57] This would, -however, include what is known to be temporary snow; the limit of -“perpetual†snow, or the true snowline, appears to lie about 19,000 feet -on Chachani and _above_ El Misti, say 19,500 feet. It is also above the -crest of Pichu-Pichu. The snowline, therefore, appears to rise a -thousand feet from Coropuna to El Misti, owing chiefly to the poorer -exposure of the latter to the sources of snowy precipitation. - -It may also be noted that the effect of the easy access of the ocean -winds in the Coropuna region is also seen in the increasing amount of -vegetation which appears in the most favorable situations. Thus, along -the Salamanca trail only a few miles from the base of Coropuna are a few -square kilometers of _quenigo_ woodland generally found in the cloud -belt at high altitudes; for example, at 14,000 feet above Lambrama and -at 9,000 feet on the slope below Incahuasi, east of Pasaje. The greater -part of the growth is disposed over hill slopes and on low ridges and -valley walls. It is, therefore, clearly unrelated as a whole to the -greater amount of ground-water with which a part is associated, as along -the valley floors of the streams that head in the belt of perpetual -snow. The appearance of this growth is striking after days of travel -over the barren, clinkery lava plateau to eastward that has a less -favorable exposure. The _quenigo_ forest, so-called, is of the greatest -economic value in a land so desolate as the vast arid and semi-arid -mountain of western Peru. Every passing traveler lays in a stock of -fire-wood as he rests his beasts at noonday; and long journeys are made -to these curious woodlands from both Salamanca and Chuquibamba to gather -fuel for the people of the towns. - - -NIVATION - -The process of nivation, or snow erosion, does not always produce -visible effects. It may be so feeble as to make no impression upon very -resistant rock where the snow-fall is light and the declivity low. -Ablation may in such a case account for almost the whole of the snow -removed. On strong and topographically varied slopes where the snow is -concentrated in headwater alcoves, there is a more pronounced downward -movement of the snow masses with more prominent effects both of erosion -beneath the snow and of accumulation at the border of the snow. In such -cases the limit of perpetual snow may be almost as definitely known as -the limit of a glacier. Like glaciers these more powerful snow masses -change their limits in response to regional changes in precipitation, -temperature, or both. It would at first sight appear impossible to -distinguish between these changes through the results of nivation. Yet -in at least a few cases it may be as readily determined as the past -limits of glaciers are inferred from the terminal moraines, still -intact, that cross the valley floors far below the present limits of the -ice. - -In discussing the process of nivation it is necessary to assume a -sliding movement on the part of the snow, though it is a condition in -Matthes’ original problem in which the nivation idea was introduced that -the snow masses remain stationary. It is believed, however, that -Matthes’ valuable observations and conclusions really involve but half -the problem of nivation; or at the most but one of two phases of it. He -has adequately shown the manner in which that phase of nivation is -expressed which we find _at the border of the snow_. Of the action -_beneath_ the snow he says merely: “Owing to the frequent oscillations -of the edge and the successive exposure of the different parts of the -site to frost action, the area thus affected will have no well-defined -boundaries. The more accentuated slopes will pass insensibly into the -flatter ones, and the general tendency will be to give the drift site a -cross section of smoothly curved outline and ordinarily concave.â€[58] - -From observations on the effects of nivation in valleys, Matthes further -concludes that “on a grade of about 12 per cent ... névé must attain a -thickness of at least 125 feet in order that it may have motion,â€[59] -though as a result of the different line of observations Hobbs -concludes[60] that a somewhat greater thickness is required. - -[Illustration: FIG. 191--The “pocked†surface characteristically -developed in the zone of light nivation. Compare with Fig. 194, showing -the effects of heavy nivation.] - -[Illustration: FIG. 192--Steep cirque walls and valleys head in the -Central Ranges between Lambrama and Chuquibambilla. The snow is here a -vigorous agent in transporting talus material and soil from all the -upper slopes down to the foot of the cirque wall.] - -The snow cover in tropical mountains offers a number of solid advantages -in this connection. Its limits, especially on the Cordillera Vilcapampa, -on the eastern border of the Andes, are subject to _small seasonal -oscillations_ and the edge of the “perpetual†snow is easily determined. -Furthermore, it is known from the comparatively “fixed quality of -tropical climate,†as Humboldt put it, that the variations of the -snowline in a period of years do not exceed rather narrow limits. In -mid-latitudes on the contrary there is an extraordinary shifting of the -margin of the snow cover, and a correspondingly wide distribution of -the feeble effects of nivation. - -[Illustration: FIG. 193--Panta Mountain and its glacier system. The -talus-covered mass in the center (B) is a terminal moraine topped by the -dirt-stained glacier that descends from the crest. The separate glaciers -were formerly united to form a huge ice tongue that truncated the -lateral spurs and flattened the valley floor. One of its former stages -is shown by the terminal moraine in the middle distance, breached by a -stream, and impounding a lake not visible from this point of view.] - -[Illustration: FIG. 194--Recessed southern slopes of volcanoes whose -northern slopes are practically without glacial modifications. Summit of -the lava plateau, Maritime Cordillera, western Peru, between Antabamba -and Cotahuasi.] - -Test cases are presented in Figs. 191, 192, and 193, Cordillera -Vilcapampa, for the determination of the fact of the movement of the -snow long before it has reached the thickness Matthes or Hobbs believes -necessary for a movement of translation to begin. Fig. 191 shows snow -masses occupying pockets on the slope of a ridge that was never covered -with ice. Past glacial action with its complicating effects is, -therefore, excluded and we have to deal with snow action pure and -simple. The pre-glacial surface with smoothly contoured slopes is -recessed in a noteworthy way from the ridge crest to the snowline of the -glacial period at least a thousand feet lower. The recesses of the -figure are peculiar in that not even the largest of them involve the -entire surface from top to bottom; they are of small size and are -scattered over the entire slope. This is believed to be due to the fact -that they represent the limits of variations of the snowline in short -cycles. Below them as far as the snowline of the glacial period are -larger recesses, some of which are terminated by masses of waste as -extensive as the neighboring moraines, but disposed in irregular -scallops along the borders of the ridges or mountain slopes in which the -recesses have been found. - -The material accumulated at the lower limit of the snow cover of the -glacial period was derived from two sources: (1) from slopes and cliffs -overlooking the snow, (2) from beneath the snow by a process akin to ice -plucking and abrasion. The first process is well known and resembles the -shedding of waste upon a valley glacier or a névé field from the -bordering cliffs and slopes. Material derived in this manner in many -places rolls down a long incline of snow and comes to rest at the foot -of it as a fringe of talus. The snow is in this case but a substitute -for a normal mass of talus. The second process produces its most clearly -recognizable effects on slopes exceeding a declivity of 20°; and upon -30° and 40° slopes its action is as well-defined as true glacial action -which it imitates. It appears to operate in its simplest form as if -independent of the mass of the snow, small and large snow patches -showing essentially the same results. This is the reverse of Matthes’ -conclusion, since he says that though the minimum thickness “must vary -inversely with the percentage of the grade,†“the influence of the grade -is inconsiderable,†and that the law of variation must depend upon -additional observation.[61] - -Let us examine a number of details and the argument based upon them and -see if it is not possible to frame a satisfactory law of variation. - -In Fig. 193 the chief conditions of the problem are set forth. Forward -from the right-hand peak are snow masses descending to the head of a -talus (_A_) whose outlines are clearly defined by freshly fallen snow. -At (_B_) is a glacier whose tributaries descend the middle and left -slopes of the picture after making a descent from slopes several -thousand feet higher and not visible in this view. The line beneath the -glacier marks the top of the moraine it has built up. Moraines farther -down valley show a former greater extent of the glacier. Clearly the -talus material at (_A_) was accumulated after the ice had retreated to -its present position. It will be readily seen from an inspection of the -photograph that the total amount of material at (_A_) is an appreciable -fraction of that in the moraine. The ratio appears to be about 1:8 or -1:10. I have estimated that the total area of snow-free surface about -the snowfields of the one is to that of the other as 2:3. The gradients -are roughly equivalent, but the volume of snow in the one case is but a -small fraction of that in the other. It will be seen that the snow -masses have recessed the mountain slopes at _A_ and formed deep hollows -and that the hollowing action appears to be most effective where the -snow is thickest. - -Summarizing, we note first, that the roughly equivalent factors are -gradient and amount of snow-free surface; second, that the unequal -factors are (a) accumulated waste, (b) degree of recessing, and (c) the -degree of compacting of snow into ice and a corresponding difference in -the character of the glacial agent, and (d) the extent of the snow -cover. The direct and important relation of the first two unequal -factors to the third scarcely need be pointed out. - -We have then an inequality in amount of accumulated material to be -explained by either an inequality in the extent of the snow and -therefore an inequality of snow action, or an inequality due to the -presence of ice in one valley and not in the other, or by both. It is at -once clear that if ice is absent above (_A_) and the mountain slopes are -recessed that snow action is responsible for it. It is also recognized -that whatever rate of denudation be assigned to the snow-free surfaces -this rate must be exceeded by the rate of snow action, else the -inequalities of slope would be decreased rather than increased. The -accumulated material at (_A_) is, therefore, partly but not chiefly due -to denudation of snow-free surfaces. It is due chiefly to _erosion_ -beneath the snow. Nor can it be argued that the hollows now occupied by -snow were formed at some past time when ice not snow lay in them. They -are not ice-made hollows for they are on a steep spur above the limits -of ice action even in the glacial period. Any past action is, therefore, -represented here in _kind_ by present action, though there would be -differences in _degree_ because the heavier snows of the past were -displaced by the lighter snows of today. - -While it appears that the case presents clear proof of degradation by -snow it is not so clear how these results were accomplished. Real -abrasion on a large scale as in bowlder-shod glaciers is ruled out, -since glacial striæ are wholly absent from nivated surfaces according to -both Matthes’ observations and my own. Yet all nivated surfaces have -very distinctive qualities, delicately organized slopes which show a -marked change from any original condition related to water-carving. In -the absence of striæ, the general absence of all but a thin coating of -waste _even in rock hollows_, and the accumulation of waste up to -bowlders in size at the lower edge of the nivated zone, I conclude that -compacted snow or névé of sufficient thickness and gradient may actually -pluck rock outcrops in the same manner though not at the rate which ice -exhibits. That the products of nivation may be bowlders as well as fine -mud would seem clearly to follow increase in effectiveness, due to -increase in amount of the accumulated snow; that bowlders are actually -transported by snow is also shown by their presence on the lower margins -of nivated tracts. - -Our argument may be made clearer by reference to the observed action of -snow in a particular valley. Snow is shed from the higher, steeper -slopes to the lower slopes and eventually accumulates to a marked degree -on the bottoms of the depressions, whence it is avalanched down valley -over a series of irregular steps on the valley floor. An avalanche takes -place through the breaking of a section of snow just as an iceberg -breaks off the end of a tide-water glacier. Evidently there must be -pressure from behind which crowds the snow forward and precipitates it -to a lower level. - -As a snow mass falls it not only becomes more consolidated, beginning at -the plane of impact, but also gives a shock to the mass upon which it -falls that either starts it in motion or accelerates its rate of motion. -The action must therefore be accompanied by a drag upon the floor and if -the rock be close-jointed and the blocks, defined by the joint planes, -small enough, they will be transported. Since snow is not so compact as -ice and permits included blocks easily to adjust themselves to new -resistances, we should expect the detached blocks included in the snow -to change their position constantly and to form irregular scratches, but -not parallel striæ of the sort confidently attributed to stone-shod ice. - -It is to the plasticity of snow that we may look for an explanation of -the smooth-contoured appearance of the landscape in the foreground of -Fig. 135. The smoothly curved lines are best developed where the entire -surface was covered with snow, as in mid-elevations in the larger -snowfields. At higher elevations, where the relief is sharper, the snow -is shed from the steeper declivities and collected in the minor basins -and valley heads, where its action tends to smooth a floor of limited -area, while snow-free surfaces retain all their original irregularities -of form or are actually sharpened. - -The degree of effectiveness of snow and névé action may be estimated -from the reversed slopes now marked by ponds or small marshy tracts -scattered throughout the former névé fields, and the many niched -hollows. They are developed above Pampaconas in an admirable manner, -though their most perfect and general development is in the summit belt -of the Cordillera Vilcapampa between Arma and Choquetira, Fig. 135. It -is notable in _all_ cases where nivation was associated with the work of -valley glaciers that the rounded nivated slopes break rather sharply -with the steep slopes that define an inner valley, whose form takes on -the flat floor and under-cut marginal walls normal to valley glaciation. - -A classification of numerous observations in the Cordillera Vilcapampa -and in the Maritime Cordillera between Lambrama and Antabamba may now be -presented as the basis for a tentative expression of the law of -variation respecting snow motion. The statement of the law should be -prefaced by the remark that thorough checking is required under a wider -range of conditions before we accept the law as final. Near the lower -border of the snow where rain and hail and alternate freezing and -thawing take place, the snow is compacted even though but fifteen to -twenty feet thick, and appears to have a down-grade movement and to -exercise a slight drag upon its floor when the gradient does not fall -below 20°. Distinct evidences of nivation were observed on slopes with a -declivity of 5° near summit areas of past glacial action, where the snow -did not have an opportunity to be alternately frozen and thawed. - -The _thickness_ of the former snow cover could, however, not be -accurately determined, but was estimated from the topographic -surroundings to have been at least several hundred feet. Upon a 40° -slope a snow mass 50 feet thick was observed to be breaking off at a -cliff-face along the entire cross-section as if impelled forward by -thrust, and to be carrying a small amount of waste--enough distinctly to -discolor the lowermost layers--which was shed upon the snowy masses -below. With increase in the degree of compactness of the snow at -successively lower elevations along a line of snow discharge, gradients -down to 25° were still observed to carry strongly crevassed, waste-laden -snow down to the melting border. It appeared from the clear evidences of -vigorous action--the accumulation of waste, the strong crevassing, the -stream-like character of the discharging snow, and the pronounced -topographic depression in which it lay--that much flatter gradients -would serve, possibly not more than 15°, for a snow mass 150 feet wide, -30 to 40 feet thick, and serving as the outlet for a set of tributary -slopes about a square mile in area and with declivities ranging from -small precipices to slopes of 30°. - -We may say, therefore, that the factors affecting the rate of motion are -(1) thickness, (2) degree of compactness, (3) diurnal temperature -changes, and (4) gradient. Among these, diurnal temperature changes -operate indirectly by making the snow more compact and also by inducing -motion directly. At higher elevations above the snowline, temperature -changes play a decreasingly important part. The thickness required -varies inversely as the gradient, and upon a 20° slope is 20 feet for -wet and compact snow subjected to alternate freezing and thawing. For -dry snow masses above the zone of effective diurnal temperature changes, -an increasing gradient is required. With a gradient of 40°, less than 50 -feet of snow will move _en masse_ if moderately compacted under its own -weight; if further compacted by impact of falling masses from above, the -required thickness may diminish to 40 feet and the required declivity to -15°. The gradient may decrease to 0° or actually be reversed and motion -still continue provided the compacting snow approach true névé or even -glacier ice as a limit. - -From the sharp topographic break between the truly glaciated portions of -the valley in regions subjected to temporary glaciation, it is concluded -that the eroding power of the moving mass is suddenly increased at the -point where névé is finally transformed into true ice. This -transformation must be assumed to take place suddenly to account for so -sudden a change of function as the topographic break requires. Below the -point at which the transformation occurs the motion takes place under a -new set of conditions whose laws have already been formulated by -students of glaciology. - -[Illustration: FIG. 195--Curve of snow motion. Based on many -observations of snow motion to show minimum thickness of snow required -to move on a given gradient. Figures on the left represent thickness of -snow in feet. The degrees represent the gradient of the surface. The -gradients have been run in sequence down to 0° for the sake of -completing the accompanying discussion. Obviously no glacially -unmodified valley in a region of mountainous relief would start with so -low a gradient, though glacial action would soon bring it into -existence. Between +5° and -5° the curve is based on the gradients of -nivated surfaces.] - -The foregoing readings of gradient and depth of snow are typical of a -large number which were made in the Peruvian Andes and which have served -as the basis of Fig. 195. It will be observed that between 15° and 20° -there is a marked change of function and again between +5° and -5° -declivity, giving a double reversed curve. The meaning of the change -between 15° and 20° is inferred to be that, with gradients over 20°, -snow cannot wholly resist gravity in the presence of diurnal temperature -changes across the freezing point and occasional snow or hail storms. -With increase of thickness compacting appears to progress so rapidly as -to permit the transfer of thrust for short distances before absorption -of thrust takes place in the displaced snow. At 250 feet thorough -compacting appears to take place, enabling the snow to move out under -its own weight on even the faintest slopes; while, with a thickness -still greater, the resulting névé may actually be forced up slight -inclines whose declivity appears to approach 5° as a limit. I have -nowhere been able to find in truly nivated areas reversed curves -exceeding 5°, though it should be added that depressions whose leeward -slopes were reversed to 2° and 3° are fairly common. If the curve were -continued we should undoubtedly find it again turning to the left at the -point where the thickness of the snow results in the transformation of -snow to ice. From the sharp topographic break observed to occur in a -narrow belt between the névé and the ice, it is inferred that the -erosive power of the névé is to that of the ice as 2:4 or 1:5 _for equal -areas_; and that reversed slopes of a declivity of 10° to 15° may be -formed by glaciers is well known. Precisely what thickness of snow or -névé is necessary and what physical conditions effect its transformation -into ice are problems not included in the main theme of this chapter. - -It is important that the proposed curve of snow motion under minimum -conditions be tested under a large variety of circumstances. It may -possibly be found that each climatic region requires its special -modifications. In tropical mountains the sudden alternations of freezing -and thawing may effect such a high degree of compactness in the snow -that lower minimum gradients are required than in the case of -mid-latitude mountains where the perpetual snow of the high and cold -situations is compacted through its own weight. Observations of the -character introduced here are still unattainable, however. It is hoped -that they will rapidly increase as their significance becomes apparent; -and that they have high significance the striking nature of the curve of -motion seems clearly to establish. - - -BERGSCHRUNDS AND CIRQUES - -The facts brought out by the curve of snow-motion (Fig. 195) have an -immediate bearing on the development of cirques, whose precise mode of -origin and development have long been in doubt. Without reviewing the -arguments upon which the various hypotheses rest, we shall begin at once -with the strongest explanation--W. D. Johnson’s famous bergschrund -hypothesis. The critical condition of this hypothesis is the diurnal -migration across the freezing point of the air temperature at the bottom -of the schrund. Alternate freezing and thawing of the water in the -joints of the rock to which the schrund leads, exercise a quarrying -effect upon the rock and, since this effect is assumed to take place at -the foot of the cirque, the result is a steady retreat of the steep -cirque wall through basal sapping. - -While Johnson’s hypothesis has gained wide acceptance and is by many -regarded as the final solution of the cirque problem it has several -weaknesses in its present form. In fact, I believe it is but one of two -factors of equal importance. In the first place, as A. C. Andrews[62] -has pointed out, it is extremely improbable that the bergschrund of -glacial times under the conditions of a greater volume of snow could -have penetrated to bedrock at the base of the cirque where the present -change of slope takes place. In the second place, the assumption is -untenable that the bergschrund in all cases reaches to or anywhere near -the foot of the cirque wall. A third condition outside the hypothesis -and contradictory to it is the absence of a bergschrund in snowfields at -many valleys heads where cirques are well developed! - -Johnson himself called attention to the slender basis of observation -upon which his conclusions rest. In spite of his own caution with -respect to the use of his meager data, his hypothesis has been applied -in an entirely too confident manner to all kinds of cirques under all -kinds of conditions. Though Johnson descended an open bergschrund to a -rock floor upon which ice rested, his observations raise a number of -proper questions as to the application of these valuable data: How long -are bergschrunds open? How often are they open? Do they everywhere open -to the foot of the cirque wall? Are they present for even a part of the -year in all well-developed cirques? Let us suppose that it is possible -to find many cirques filled with snow, not ice, surrounded by truly -precipitous walls and with an absence of bergschrunds, how shall we -explain the topographic depressions excavated underneath the snow? If -cirque formation can be shown to take place without concentrated frost -action at the foot of the bergschrund, then is the bergschrund not a -secondary rather than a primary factor? And must we not further conclude -that when present it but hastens an action which is common to all -snow-covered recesses? - -It is a pleasure to say that we may soon have a restatement of the -cirque problem from the father of the bergschrund idea. The argument in -this chapter was presented orally to him after he had remarked that he -was glad to know that some one was finding fault with his hypothesis. -“For,†he said, with admirable spirit, “I am about to make a most -violent attack upon the so-called Johnson hypothesis.†I wish to say -frankly that while he regards the following argument as a valid addition -to the problem, he does not think that it solves the problem. There are -many of us who will read his new explanation with the deepest interest. - -[Illustration: FIG. 196--Relation of cirque wall to trough’s end at the -head of a glaciated valley. The ratio of the inner to the outer radius -is 1:4.] - -[Illustration: FIG. 197--Mode of cirque formation. Taking the facts of -snow depth represented in the curve, Fig. 195, and transposing them over -a profile (the heavy line) which ranges from 0° declivity to 50°, we -find that the greatest excess of snow occurs roughly in the center. Here -ice will first form at the bottom of the snow in the advancing hemicycle -of glaciation, and here it will linger longest in the hemicycle of -retreat. Here also there will be the greatest mass of névé. All of these -factors are self-stimulating and will increase in time until the floor -of the cirque is flattened or depressed sufficiently to offset through -uphill ice-flow the augmented forces of erosion. The effects of -self-stimulation are shown by “snow increaseâ€; the ice shoe at the -bottom of the cirque is expressed by “ice factor.†The form accompanying -both these terms is merely suggestive. The top of “excess snow†has a -gradient characteristic of the surface of snow fields. A preglacial -gradient of 0° is not permissible, but I have introduced it to complete -the discussion in the text and to illustrate the flat floor of a cirque. -A bergschrund is not required for any stage of this process, though the -process is hastened wherever bergschrunds exist.] - -We shall begin with the familiar fact that many valleys, now without -perpetual snow, formerly contained glaciers from 500 to 1,000 feet thick -and that their snowfields were of wide extent and great depth. At the -head of a given valley where the snow is crowded into a small -cross-section it is compacted and suffers a reduction in its volume. At -first nine times the volume of ice, the gradually compacting névé -approaches the volume of ice as a limit. At the foot of the cirque wall -we may fairly assume in the absence of direct observations, a volume -reduction of one-half due to compacting. But this is offset in the case -of a well-developed cirque by volume increases due to the convergence of -the snow from the surrounding slopes, as shown in Fig. 196. Taking a -typical cirque from a point above Vilcabamba pueblo I find that the -radius of the trough’s end is to the radius of the upper wall of the -cirque as 1:4; and since the corresponding surfaces are to one another -as the squares of their similar dimensions we have 1:4 or 1:16 as the -ratio of their snow areas. If no compacting took place, then to -accommodate all the snow in the glacial trough would require an increase -in thickness in the ratio of 1:4. If the snow were compacted to half its -original volume then the ratio would be 1:2. Now, since the volume ratio -of ice to snow is 1:9 and the thickness of the ice down valley is, say -400 feet, the equivalent of loose snow at the foot of the cirque must be -more than 1:4 over 1:9 or more than two and one-quarter times thicker, -or 400 feet thick; and would give a pressure of (900 ÷ 10) × 62.5 -pounds, or 5,625 pounds, or a little less than three tons per square -foot. Since a pressure of 2,500 pounds per square foot will convert snow -into ice at freezing temperature, it is clear that ice and not snow was -the state at the bottom of the mass in glacial times. Further, between -the surface of the snow and the surface of the bottom layer of the ice -there must have been every gradation between loose snow and firm ice, -with the result that a thickness much less than 900 feet must be -assumed. Precisely what thickness would be found at the foot of the -cirque wall is unknown. But granting a thickness of 400 feet of ice an -additional 300 feet for névé and snow would raise the total to 700 feet. - -The application of the facts in the above paragraph is clearly seen when -we refer to Fig. 197. The curve of snow motion of Fig. 195 is applied to -an unglaciated mountain valley. Taking a normal snow surface and filling -the valley head it is seen that the excess of snow depth over the amount -required to give motion is a measure at various points in the valley -head and at different gradients of the erosive force of the snow. It is -strikingly concentrated on the 15°-20° gradient which is precisely where -the so-called process of basal sapping is most marked. If long continued -the process will lead to the developing of a typical cirque for it is a -process that is self-stimulating. The more the valley is changed in form -the more it tends to change still further in form because of deepening -snowfields until cliffed pinnacles and matterhorns result. - -By further reference to the figure it is clear that a schrund 350 feet -deep could not exist on a cirque wall with a declivity of even 20° -without being closed by flow, unless we grant _more rapid flow_ below -the crevasse. In the case of a glacier flowing over a nearly flat bed -away from the cirque it is difficult to conceive of a rate of flow -greater than that of snow and névé on the steep lower portion of the -cirque wall, when movement on that gradient _begins_ with snow but 20 -feet thick. - -In contrast to this is the view that the schrund line should lie well up -the cirque wall where the snow is comparatively thin and where there is -an approach to the lower limits of movement. The schrund would appear to -open where the bottom material changes its form, i.e., where it first -has its motion accelerated by transformation into névé. In this view -the schrund opens not at the foot of the cirque wall but well above it -as in Fig. 198, in which _C_ represents snow from top to bottom; _B_, -névé; and _A_, ice. The required conditions are then (1) that the -steepening of the cirque wall from _x_ to _y_ should be effected by -sapping originated at _y_ through the agencies outlined by Johnson; (2) -that the steepening from _x_ to _y_ should be effected by sapping -originated at _x_ through the change of the agent from névé to ice with -a sudden change of function; (3) and that the essential unity of the -wall _x-y-z_ be maintained through the erosive power of the névé, which -would tend to offset the formation of a shelf along a horizontal plane -passed through _y_. The last-named process not only appears entirely -reasonable from the conditions of gradient and depth outlined on pp. 296 -to 298, but also meets the actual field conditions in all the cases -examined in the Peruvian Andes. This brings up the second and third of -our main considerations, that the bergschrund does not always or even in -many cases reach the foot of the cirque wall, and that cirques exist in -many cases where bergschrunds are totally absent. - -It is a striking fact that frost action at the bottom of the bergschrund -has been assumed to be the only effective sapping force, in spite of the -common observation that bergschrunds lie in general well toward the -upper limits of snowfields--so far, in fact, that their bottoms in -general occur several hundred feet above the cirque floors. Is the -cirque under these circumstances a result of the schrund or is the -schrund a result of the cirque? _In what class of cirques do schrunds -develop?_ If cirque development in its early stages is not marked by the -development of bergschrunds, then are bergschrunds an _essential_ -feature of cirques in their later stages, however much the sapping -process may be hastened by schrund formation? - -Our questions are answered at once by the indisputable facts that many -schrunds occur well toward the upper limit of snow, and that many -cirques exist whose snowfields are not at all broken by schrunds. It was -with great surprise that I first noted the bergschrunds of the Central -Andes, especially after becoming familiar with Johnson’s apparently -complete proof of their genetic relation to the cirques. But it was less -surprising to discover the position of the few observed--high up on the -cirque walls and always near the upper limit of the snowfields. - -A third fact from regions once glaciated but now snow-free also combined -with the two preceding facts in weakening the wholesale application of -Johnson’s hypothesis. In many headwater basins the cirque whose wall at -a distance seemed a unit was really broken into two unequal portions; a -lower, much grooved and rounded portion and an upper unglaciated, -steep-walled portion. This condition was most puzzling in view of the -accepted explanation of cirque formation, and it was not until the two -first-named facts and the applications of the curves of snow motion were -noted that the meaning of the break on the cirque became clear. -Referring to Fig. 198 we see at once that the break occurs at _y_ and -means that under favorable topographic and geologic conditions sapping -at _y_ takes place faster than at _x_ and that the retreat of _y-z_ is -faster than _x-y_. It will be clear that when these conditions are -reversed or sapping at _x_ and at _y_ are equal a single wall will -result. On reference to the literature I find that Gilbert recently -noted this feature and called it the _schrundline_.[63] He believes that -it marks the base of the bergschrund _at a late stage in the excavation -of the cirque basin_. He notes further that the lower less-steep slope -is glacially scoured and that it forms “a sort of shoulder or terrace.†- -[Illustration: FIG. 198--The development of cirques. See text, p. 209, -and Fig. 199.] - -If all the structural and topographic conditions were known in a great -variety of gathering basins we should undoubtedly find in them, and not -in special forms of ice erosion, an explanation of the various forms -assumed by cirques. The limitations inherent in a high-altitude field -and a limited snow cover prevented me from solving the problem, but it -offered sufficient evidence at least to indicate the probable lines of -approach to a solution. For example it is noteworthy that in _all_ the -cases examined the schrundline was better developed the further glacial -erosion had advanced. So constantly did this generalization check up, -that if at a distance a short valley was observed to end in a cirque, I -knew at once and long before I came to the valley head that a shoulder -below the schrundline did not exist. At the time this observation was -made its significance was a mystery, but it represents a condition so -constant that it forms one of the striking features of the glacial forms -in the headwater region. - -[Illustration: FIG. 199--Further stages in the development of cirques. -See p. 299 and Fig. 198.] - -The meaning of this feature is represented in Fig. 199, in which three -successive stages in cirque development are shown. In _A_, as displayed -in small valleys or mountainside alcoves which were but temporarily -occupied by snow and ice, or as in all higher valleys during the earlier -stages of the advancing hemicycle of glaciation, snow collects, a short -glacier forms, and a bergschrund develops. As a result of the -concentrated frost action at the base of the bergschrund a rapid -deepening and steepening takes place at _a_. As long as the depth of -snow (or snow and névé) is slight the bergschrund may remain open. But -its existence at this particular point is endangered as the cirque -grows, since the increasing steepness of the slope results in more rapid -snow movement. Greater depth of snow goes hand in hand with increasing -steepness and thus favors the formation of névé and even ice at the -bottom of the moving mass and a constantly accelerated rate of motion. -At the same time the bergschrund should appear higher up for an -independent reason, namely, that it tends to form between a mass of -slight movement and one of greater movement, which change of function, -as already pointed out, would appear to be controlled by change from -snow to névé or ice on the part of the bottom material. - -The first stages in the upward migration of the bergschrund will not -effect a marked change from the original profile, since the converging -slopes, the great thickness of névé and ice at this point, and the steep -gradient all favor powerful erosion. When, however, stage _C_ is -reached, and the bergschrund has retreated to _c″_, a broader terrace -results below the schrundline, the gradient is decreased, the ice and -névé (since they represent a constant discharge) are spread over a -greater area, hence are thinner, and we have the cirque taking on a -compound character with a lower, less steep and an upper, precipitous -section. - -It is clear that a closely jointed and fragile rock might be quarried by -moving ice at _c′-c″_ and the cirque wall extended unbroken to _x_; it -is equally clear that a homogeneous, unjointed granite would offer no -opportunities for glacial plucking and would powerfully resist the much -slower process of abrasion. Thus Gilbert[64] observed the schrundline in -the granites of the Sierra Nevada, which are “in large part -structureless†and my own observations show the schrundline well -developed in the open-jointed granites of the Cordillera Vilcapampa and -wholly absent in the volcanoes of the Maritime Cordillera, where ashes -and cinders, the late products of volcanic action, form the easily -eroded walls of the steep cones. Somewhere between these extremes--lack -of a variety of observations prevents our saying where--the resistance -and the internal structure of the rock will just permit a cirque wall to -extend from _x_ to _c′ ″_ of Fig. 199. - -A common feature of cirques that finds an explanation in the proposed -hypothesis is the notch that commonly occurs at some point where a -convergence of slopes above the main cirque wall concentrates snow -discharge. It is proposed to call this type the notched cirque. It is -highly significant that these notches are commonly marked by even -steeper descents at the point of discharge into the main cirque than the -remaining portion of the cirque wall, even when the discharge was from a -very small basin and in the form of snow or at the most névé. The excess -of discharge at a point on the basin rim ought to produce the form we -find there under the conditions of snow motion outlined in earlier -paragraphs. It is also noteworthy that it is at such a point of -concentrated discharge that crevasses no sooner open than they are -closed by the advancing snow masses. To my mind the whole action is -eminently representative of the action taking place elsewhere along the -cirque wall on a smaller scale. - -What seems a good test of the explanation of cirques here proposed was -made in those localities in the Maritime Cordillera, where large -snowbanks but not glaciers affect the form of the catchment basins. A -typical case is shown in Fig. 201. As in many other cases we have here a -great lava plateau broken frequently by volcanic cones of variable -composition. Some are of lava, others consist of ashes, still others of -tuff and lava and ashes. At lower elevations on the east, as at 16,000 -feet between Antabamba and Huancarama, evidences of long and powerful -glaciers are both numerous and convincing. But as we rise still higher -the glaciated topography is buried progressively deeper under the -varying products of volcanic action, until finally at the summit of the -lava fields all evidences of glaciation disappear in the greater part of -the country between Huancarama and the main divide. Nevertheless, the -summit forms are in many cases as significantly altered as if they had -been molded by ice. Precipitous cirque walls surround a snow-filled -amphitheater, and the process of deepening goes forward under one’s -eyes. No moraines block the basin outlets, no U-shaped valleys lead -forward from them. We have here to do with post-glacial action pure and -simple, the volcanoes having been formed since the close of the -Pleistocene. - -Likewise in the pass on the main divide, the perpetual snow has begun -the recessing of the very recent volcanoes bordering the pass. The -products of snow action, muds and sands up to very coarse gravel, -glaciated in texture with an intermingling of blocks up to six inches in -diameter in the steeper places, are collected into considerable masses -at the snowline, where they form broad sheets of waste so boggy as to be -impassable except by carefully selected routes. No ice action whatever -is visible below the snowline and the snow itself, though wet and -compact, is not underlain by ice. Yet the process of hollowing goes -forward visibly and in time will produce serrate forms. In neither case -is there the faintest sign of a bergschrund; the gradients seem so well -adjusted to the thickness and rate of movement of the snow from point to -point that the marginal crack found in many snowfields is absent. - -The absence of bergschrunds is also noteworthy in many localities where -formerly glaciation took place. This is notoriously the case in the -summit zone of the Cordillera Vilcapampa, where the accumulating snows -of the steep cirque walls tumble down hundreds of feet to gather into -prodigious snowbanks or to form névé fields or glaciers. From the -converging walls the snowfalls keep up an intermittent bombardment of -the lower central snow masses. It is safe to say that if by magic a -bergschrund could be opened on the instant, it would be closed almost -immediately by the impetus supplied by the falling snow masses. The -explanation appears to be that the thicker snow and névé concentrated at -the bottom of the cirque results in a corresponding concentration of -action and effect; and cirque development goes on without reference to a -bergschrund. The chief attraction of the bergschrund hypothesis lies in -the concentration of action at the foot of the cirque wall. But in the -thickening of the snow far beyond the minimum thickness required for -motion at the base of the cirque wall and its change of function with -transformation into névé, we need invoke no other agent. If a -bergschrund forms, its action may take place at the foot of the cirque -wall or high up on the wall, and yet _sapping at the foot of the wall_ -continue. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM DIRECTOR - -LAMBRAMA QUADRANGLE] - -From which we conclude (1) that where frost action occurs at the bottom -of a bergschrund opening to the foot of the cirque wall it aids in the -retreat of the wall; (2) that a sapping action takes place at this point -whether or not a bergschrund exists and that bergschrund action is not a -_necessary_ part of cirque formation; (3) that when a more or less -persistent bergschrund opens on the cirque wall above its foot it tends -to develop a schrundline with a marked terrace below it; (4) that -schrundlines are best developed in the mature stages of topographic -development in the glacial cycle; (5) that the varying rates of snow, -névé, and ice motion at a valley head are the _persistent_ features to -which we must look for topographic variations; (6) that the hypothesis -here proposed is applicable to all cases whether they involve the -presence of snow or névé or ice or any combination of these, and whether -bergschrunds are present or not; and (7) at the same time affords a -reasonable explanation for such variations in forms as the compound -cirque with its schrundline and terrace, the unbroken cirque wall, the -notched cirque, and the recessed, snow-covered mountain slopes -unaffected by ice. - - -ASYMMETRICAL CREST LINES AND ABNORMAL VALLEY PROFILES IN THE CENTRAL -ANDES - -To prove that under similar conditions glacial erosion may be greater -than subaërial denudation quantitative terms must be sought. Only these -will carry conviction to the minds of many opponents of the theory that -ice is a vigorous agent of erosion. Gilbert first showed in the Sierra -Nevada that headwater glaciers eroded more rapidly than nonglacial -agents under comparable topographic and structural conditions.[65] Oddly -enough none of the supporters of opposing theories have replied to his -arguments; instead they have sought evidence from other regions to show -that ice cannot erode rock to an important degree. In this chapter -evidence from the Central Andes, obtained in 1907 and 1911, will be -given to show the correctness of Gilbert’s proposition. - -The data will be more easily understood if Gilbert’s argument is first -outlined. On the lower slopes of the glaciated Sierra Nevada asymmetry -of form resulted from the presence of ice on one side of each ridge and -its absence on the other (Fig. 200). The glaciers of these lower ridges -were the feeblest in the entire region and were formed on slopes of -small extent; they were also short-lived, since they could have existed -only when glacial conditions had reached a maximum. Let the broken line -in the upper part of the figure represent the preglacial surface and -the solid line beneath it the present surface. It will not matter what -value we give the space between the two lines on the left to express -nonglacial erosion, since had there been no glaciers it would be the -same on both sides of the ridge. The feeble glacier occupying the -right-hand slope was able in a very brief period to erode a depression -far deeper than the normal agents of denudation were able to erode in a -much longer period, i.e., during all of interglacial and postglacial -time. Gilbert concludes: “The visible ice-made hollows, therefore, -represent the local excess of glacial over nonglacial conditions.†- -[Illustration: FIG. 200--Diagrammatic cross-section of a ridge glaciated -on one side only; with hypothetical profile (broken line) of preglacial -surface.] - -[Illustration: FIG. 201--Postglacial volcano recessed on shady southern -side by the process of nivation. Absolute elevation 18,000 feet (5,490 -m.), latitude 14° S., Maritime Cordillera, Peru.] - -In the Central Andes are many volcanic peaks and ridges formed since the -last glacial epoch and upon them a remarkable asymmetry has been -developed. Looking southward one may see a smoothly curved, snow-free, -northward-facing slope rising to a crest line which appears as regular -as the slope leading to it. Looking northward one may see by contrast -(Fig. 194) sharp ridges, whose lower crests are serrate, separated by -deeply recessed, snow-filled mountain hollows. Below this highly -dissected zone the slopes are smooth. The smooth slope represents the -work of water; the irregular slopes are the work of snow and ice. The -relation of the north and south slopes is diagrammatically shown in Fig. -201. - -To demonstrate the erosive effects of snow and ice it must be shown: (1) -that the initial slopes of the volcanoes are of postglacial age; (2) -that the asymmetry is not structural; (3) that the snow-free slopes have -not had special protection, as through a more abundant plant cover, more -favorable soil texture, or otherwise. - -Proof of the postglacial origin of the volcanoes studied in this -connection is afforded: (1) by the relation of the flows and the ash and -cinder beds about the bases of the cones to the glacial topography; (2) -by the complete absence of glacial phenomena below the present snowline. -Ascending a marginal valley (Fig. 202), one comes to its head, where two -tributaries, with hanging relations to the main valley, come down from a -maze of lesser valleys and irregular slopes. Glacial features of a -familiar sort are everywhere in evidence until we come to the valley -heads. Cirques, reversed grades, lakes, and striæ are on every hand. But -at altitudes above 17,200 feet, recent volcanic deposits have over large -areas entirely obscured the older glacial topography. The glacier which -occupied the valley of Fig. 202 was more than one-quarter of a mile -wide, the visible portion of its valley is now over six miles long, but -the extreme head of its left-hand tributary is so concealed by volcanic -material that the original length of the glacier cannot be determined. -It was at least ten miles long. From this point southward to the border -of the Maritime Cordillera no evidence of past glaciation was observed, -save at Solimana and Coropuna, where slight changes in the positions of -the glaciers have resulted in the development of terminal moraines a -little below the present limits of the ice. - -From the wide distribution of glacial features along the northeastern -border of the Maritime Cordillera and the general absence of such -features in the higher country farther south, it is concluded that the -last stages of volcanic activity were completed in postglacial time. It -is equally certain, however, that the earlier and greater part of the -volcanic material was ejected before glaciation set in, as shown by the -great depth of the canyons (over 5,000 feet) cut into the lava flows, as -contrasted with the relatively slight filling of coarse material which -was accumulated on their floors in the glacial period and is now in -process of dissection. Physiographic studies throughout the Central -Andes demonstrate both the general distribution of this fill and its -glacial origin. - -So recent are some of the smaller peaks set upon the lava plateau that -forms the greater part of the Maritime Cordillera, that the snows massed -on their shadier slopes have not yet effected any important topographic -changes. The symmetrical peaks of this class are in a few cases so very -recent that they are entirely uneroded. Lava flows and beds of tuff -appear to have originated but yesterday, and shallow lava-dammed lakes -retain their original shore relations. In a few places an older -topography, glacially modified, may still be seen showing through a -veneer of recent ash and cinder deposits, clear evidence that the -loftier parts of the lava plateau were glaciated before the last -volcanic eruption. - -The asymmetry of the peaks and ridges in the Maritime Cordillera cannot -be ascribed to the manner of eruption, since the contrast in declivity -and form is persistently between northern and southern slopes. Strong -and persistent winds from a given direction undoubtedly influence the -form of volcanoes to at least a perceptible degree. In the case in hand -the ejectamenta are ashes, cinders, and the like, which are blown into -the air and have at least a small component of motion down the wind -during both their ascent and descent. The _prevailing_ winds of the high -plateaus are, however, easterly and the strongest winds are from the -west and blow daily, generally in the late afternoon. Both wind -directions are at right angles to the line of asymmetry, and we must, -therefore, rule out the winds as a factor in effecting the slope -contrasts which these mountains display. - -It remains to be seen what influence a covering of vegetation on the -northern slopes might have in protecting them from erosion. The northern -slopes in this latitude (14° S.) receive a much greater quantity of heat -than the southern slopes. Above 18,000 feet (5,490 m.) snow occurs on -the shady southern slopes, but is at least a thousand feet higher on the -northern slopes. It is therefore absent from the northern side of all -but the highest peaks. Thus vegetation on the northern slopes is not -limited by snow. Bunch grass--the characteristic _ichu_ of the mountain -shepherds--scattered spears of smaller grasses, large ground mosses -called _yareta_, and lichens extend to the snowline. This vegetation, -however, is so scattered and thin above 17,500 feet (5,330 m.) that it -exercises no retarding influence on the run-off. Far more important is -the porous nature of the volcanic material, which allows the rainfall to -be absorbed rapidly and to appear in springs on the lower slopes, where -sheets of lava direct it to the surface. - -The asymmetry of the north and south slopes is not, then, the result of -preglacial erosion, of structural conditions, or of special protection -of the northern slopes from erosion. It must be concluded, therefore, -that it is due to the only remaining factor--snow distribution. The -southern slopes are snow-clad, the northern are snow-free--in harmony -with the line of asymmetry. The distribution of the snow is due to the -contrasts between shade and sun temperatures, which find their best -expression in high altitudes and on single peaks of small extent. -Frankland’s observations with a black-bulb thermometer _in vacuo_ show -an increase in shade and sun temperatures contrasts of over 40° between -sea level and an elevation of 10,000 feet. Violle’s experiments show an -increase of 26 per cent in the intensity of solar radiation between 200 -feet and 16,000 feet elevation. Many other observations up to 16,000 -feet show a rapid increase in the difference between sun and shade -temperatures with increasing elevation. In the region herein described -where the snowline is between 18,000 and 19,000 feet (5,490 to 5,790 m.) -these contrasts are still further heightened, especially since the -semi-arid climate and the consequent long duration of sunshine and low -relative humidity afford the fullest play to the contrasting forces. The -coefficient of absorption of radiant energy by water vapor is 1,900 -times that of air, hence the lower the humidity the more the radiant -energy expended upon the exposed surface and the greater the sun and -shade contrasts. The effect of these temperature contrasts is seen in a -canting of the snowline on individual volcanoes amounting to 1,500 feet -in extreme instances. The average may be placed at 1,000 feet. - -The minimum conditions of snow motion and the bearing of the conclusions -upon the formation of cirques have been described in the chapters -immediately preceding. It is concluded that snow moves upon 20° slopes -if the snow is at least forty feet deep, and that through its motion -under more favorable conditions of greater depth and gradient and the -indirect effects of border melting there is developed a hollow occupied -by the snow. Actual ice is not considered to be a necessary condition of -either movement or erosion. We may at once accept the conclusion that -the invariable association of the cirques and steepened profiles with -snowfields proves that snow is the predominant modifying agent. - -An argument for glacial erosion based on profiles and steep cirque walls -in a volcanic region has peculiar appropriateness in view of the -well-known symmetrical form of the typical volcano. Instead of varied -forms in a region of complex structure long eroded before the appearance -of the ice, we have here simple forms which immediately after their -development were occupied by snow. _Ever since their completion these -cones have been eroded by snow on one side and by water on the other._ -If snow cannot move and if it protects the surface it covers, then this -surface should be uneroded. All such surfaces should stand higher than -the slopes on the opposite aspect eroded by water. But these assumptions -are contrary to fact. The slopes underneath the snow are deeply -recessed; so deeply eroded indeed, that they are bordered by steep -cliffs or cirque walls. The products of erosion also are to some extent -displayed about the border of the snow cover. In strong contrast the -snow-free slopes are so slightly modified that little of their original -symmetry is lost--only a few low hills and shallow valleys have been -formed. - -The measure of the excess of snow erosion over water erosion is -therefore the difference between a northern or water-formed and a -southern or snow-formed profile, Fig. 200. This difference is also shown -in Fig. 201 and from it and the restored initial profiles we conclude -that the rate of water erosion is to that of nivation as 1:3. This ratio -has been derived from numerous observations on cones so recently formed -that the interfluves without question are still intact. - -Thus far only those volcanoes have been considered which have been -modified by nivation. There are, however, many volcanoes which have been -eroded by ice as well as by snow and water. It will be seen at once that -where a great area of snow is tributary to a single valley, the snow -becomes compacted into névé and ice, and that it then erodes at a much -faster rate. Also a new force--plucking--is called into action when ice -is present, and this greatly accelerates the rate of erosion. While it -lies outside the limits of my subject to determine quantitatively the -ratio between water and ice action, it is worth pointing out that by -this method a ratio much in excess of 1:3 is determined, which even in -this rough form is of considerable interest in view of the arguments -based on the protecting influence of both ice and snow. I have, indeed, -avoided the question of ice erosion up to this point and limited myself -to those volcanoes which have been modified by nivation only, since the -result is more striking in view of the all but general absence of data -relating to this form of erosion. - -[Illustration: FIG. 202--Graphic representation of amount of glacial -erosion during the glacial period. In the background are mature slopes -surmounted by recessed asymmetrical peaks. The river entrenched itself -below the mature slopes before it began to aggrade, and, when -aggradation set in, had cut its valley floor to a′-b′-c. By aggradation -the valley floor was raised to a-b while ice occupied the valley head. -By degradation the river has again barely lowered its channel to a′-b′, -the ice has disappeared, and the depression of the profile represents -the amount of glacial erosion. - -a′-b′-c = preglacial profile. - -a-b-d-c = present profile. - -b′-d-c-b = total ice erosion in the glacial period. - -a-b = surface of an alluvial valley fill due to - excessive erosion at valley head. - -b-b′ = terminal moraine. - -d-c = cirque wall. - -e, e′ e″ = asymmetrical summits.] - -[Illustration: FIG. 203--A composite sketch to represent general -conditions in the Peruvian Andes. In order to have the actual facts -represented the profiles of this figure were taken from the accompanying -topographic sheets. The main depression on the right and the -corresponding depression of the tributary profiles bear out most -strikingly the conclusions concerning the erosive power of the ice. At -_A_ and _B_ the spurs have been cut off to exhibit the profiles of -tributary valleys. At _2_ and _3_ were tributary glaciers of such size -that they entered the main valley at grade. Lesser tributaries had -floors elevated above those they joined and now have a hanging -character, as just above _2_. _D_ is a matterhorn; _C_ is deeply -recessed by cirques; _E_ represents a peak just below the limit of -glaciation. At _F_ are the undissected post-mature slopes of an earlier -cycle of erosion. _G_ lies on the steep lower slopes formed during the -canyon cycle of erosion. The down-cutting of the stream in the canyon -cycle was generally checked by glaciation and was superseded by -aggradation.] - -If we now turn to the valley profiles of the glaciated portions of the -Peruvian Andes, we shall see the excess of ice over water erosion -expressed in a manner equally convincing. To a thoughtful person it is -one of the most remarkable features of any glaciated region that the -flattest profiles, the marshiest valley flats, and the most strongly -meandering stretches of the streams should occur near the heads of the -valleys. The mountain shepherds recognize this condition and drive -their flocks up from the warmer valley into the mountain recesses, -confident that both distance and elevation will be offset by the -extensive pastures of the finest _ichu_ grass. Indeed, to be near the -grazing grounds of sheep and llamas which are their principal means of -subsistence, the Indians have built their huts at the extraordinarily -lofty elevations of 16,000 to 17,000 feet. - -An examination of a large number of these valleys and the plotting of -their gradients discloses the striking fact that the heads of the -valleys were deeply sunk into the mountains. It is thus possible by -restoring the preglacial profiles to measure with considerable certainty -the excess of ice over water erosion. - -The results are graphically expressed in Fig. 202. It will be seen that -until glacial conditions intervened the stream was flowing on a rock -floor. During the whole of glacial time it was aggrading its rock floor -below _b′_ and forming a deep valley fill. A return to warmer and drier -conditions led to the dissection of the fill and this is now in -progress. The stream has not yet reached its preglacial profile, but it -has almost reached it. We may, therefore, say that the preglacial valley -profile below _b′_ fixes the position of the present profile just as -surely as if the stream had been magically halted in its work at the -beginning of the period of glaciation. There, _b′-d-c-b_ represents the -amount of ice erosion. To be sure the line _b-c_ is inference, but it is -reasonable inference and, whatever position is assigned to it, it cannot -be coincident with _b′-d_, nor can it be anywhere near it. The break in -the valley profile at _b′_ is always marked by a terminal moraine, -regardless of the character of the rock. This is not an accidental but a -causal association. It proves the power of the ice to erode. In glacial -times it eroded the quantity _b-c-d-b′_. This is not an excess of ice -over water erosion, but an absolute measure of ice erosion, since -_a′-b′_ has remained intact. The only possible error arises from the -position assigned _b-c_, and even if we lower it to _b-c′_ (for which we -have no warrant but extreme conservatism) we shall still have left -_b′-c′-d-b_ as a striking value for rock erosion (plucking and abrasion) -by a valley glacier. - -A larger diagram, Fig. 203, represents in fuller detail the topographic -history of the Andes of southern Peru and the relative importance of -glaciation. The broad spurs with grass-covered tops that end in steep -scarps are in wonderful contrast to the serrate profiles and truncated -spurs that lie within the zone of past glaciation. In the one case we -have minute irregularities on a canyon wall of great dimensions; in the -other, more even walls that define a glacial trough with a flat floor. -Before glaciation on a larger scale had set in the right-hand section of -the diagram had a greater relief. It was a residual portion of the -mountain and therefore had greater height also. Glaciers formed upon it -in the Ice Age and glaciation intensified the contrast between it and -the left-hand section; not so much by intensifying the relief as by -diversifying the topographic forms. - -[Illustration: FIG. 204--Topographic map of the Andes between Abancay -and the Pacific Coast at Camaná. Compiled from the seven accompanying -topographic sheets (see Contents, p. xi). Scale 1:1,000,000. Contour -interval 1,000 feet. Longitude west of Greenwich. The Central Ranges of -the Maritime Cordillera are not confined to the area covered by these -names. In the one case the term includes all the ranges between Lambrama -and Huichihua; in the other case, the peaks and ranges from 14° 30′ S. -to Mt. Coropuna.] - - - - -APPENDIX A - -SURVEY METHODS EMPLOYED IN THE CONSTRUCTION OF THE SEVEN ACCOMPANYING -TOPOGRAPHIC SHEETS - -BY KAI HENDRIKSEN, TOPOGRAPHER - - -The main part of the topographical outfit consisted of (1) a 4-inch -theodolite, Buff and Buff, the upper part detachable, (2) an 18 x 24 -inch plane-table with Johnson tripod and micro-meteralidade. These -instruments were courteously loaned the expedition by the U. S. Coast -and Geodetic Survey and the U. S. Geological Survey respectively. - -The method of survey planned was a combination of graphic triangulation -and traverse with the micro-meteralidade. All directions were plotted on -the plane-table which was oriented by backsight; distances were -determined by the micro-meteralidade or triangulation, or both combined; -and elevations were obtained by vertical angles. Finally, astronomical -observations, usually to the sun, were taken at intervals of about 60 -miles for latitude and azimuth to check the triangulation. No -observations were made for differences in longitude because this would -probably not have given any reliable result, considering the time and -instruments at our disposal. Because the survey was to follow very -closely the seventy-third meridian west of Greenwich, directions and -distances, checked by latitude and azimuth observations, undoubtedly -afforded far better means of determining the longitude than time -observations. In other words, the time observations made in connection -with azimuth observations were not used for computing longitudinal -differences. Absolute longitude was taken from existing observations of -principal places. - -Principal topographical points were located by from two to four -intersections from the triangulation and plane-table stations; and -elevations were determined by vertical angle measurements. Whenever -practicable, the contours were sketched in the field; the details of the -topography otherwise depend upon a great number of photographs taken by -Professor Bowman from critical stations or other points which it was -possible to locate on the maps. - - -CROSS-SECTION MAP FROM ABANCAY TO CAMANà AT THE PACIFIC OCEAN - -Seven sheets. Scale, 1:125,000; contour interval, 200 feet. Datum is -mean sea level. Astronomical control: 5 latitude and 5 azimuth -observations as indicated on the accompanying topographic sheets. - -On September 10th, returning from a reconnaissance survey of the -Pampaconas River, I joined Professor Bowman’s party, Dr. Erving acting -as my assistant. We crossed the Cordillera Vilcapampa and the Canyon of -the Apurimac and after a week’s rest at Abancay started the topographic -work near Hacienda San Gabriel south of Abancay. Working up the deep -valley of Lambrama, observations for latitude and azimuth were made -midway between Hacienda Matara and Caypi. - -On October 4th we made our camp in newly fallen snow surrounded by -beautiful glacial scenery. The next day on the high plateau, we passed -sharp-crested glaciated peaks; a heavy thunder and hail storm broke out -while I occupied the station at the pass, the storm continuing all the -afternoon--a frequent occurrence. The camp was made 6 miles farther on, -and the next morning I returned to finish the latter station. I -succeeded in sketching the detailed topography just south of the pass, -but shortly after noon, a furious storm arose similar to the one the day -before, and made further topographic work impossible; to get connection -farther on I patiently kept my eye to the eye-piece for more than an -hour after the storm had started, and was fortunate to catch the station -ahead in a single glimpse. I had a similar experience some days later at -station 16,079, Antabamba Quadrangle, on the rim of the high-level puna, -the storm preventing all topographic work and barely allowing a single -moment in which to catch a dim sight of the signals ahead while I kept -my eye steadily at the telescope to be ready for a favorable break in -the heavy clouds and hail. - -At Antabamba we got a new set of Indian carriers, who had orders to -accompany us to Cotahuasi, the next sub-prefectura. Raimondi’s map -indicates the distance between the two cities to be 35 miles, but -although nothing definite was stated, we found out in Antabamba that the -distance was considerably longer, and moreover that the entire route lay -at a high altitude. - -From the second day out of Antabamba until Huaynacotas was in sight in -the Cotahuasi Canyon, a distance of 50 miles, the route lay at an -altitude of from 16,000 to 17,630 feet, taking in 5 successive camps at -an altitude from 15,500 to 17,000 feet; 12 successive stations had the -following altitudes: - - 16,379 feet - 16,852 " - 17,104 " - 17,559 " - 17,675 " --highest station occupied. - 17,608 " - 17,633 " - 16,305 " - 17,630 " - 17,128 " - 16,794 " - 16,260 " - -The occupation of these high stations necessitated a great deal of -climbing, doubly hard in this rarefied air, and often on volcanoes with -a surface consisting of bowlders and ash and in the face of violent -hailstorms that made extremely difficult the task of connecting up -observations at successive stations. - -At Cotahuasi a new pack-train was organized, and on October 25th I -ventured to return alone to the high altitudes in order to continue the -topography at the station at 17,633 feet on the summit of the Maritime -Cordillera. Dr. Erving was obliged to leave on October 18th and -Professor Bowman left a week later in order to carry out his plans for a -physiographic study of the coast between Camaná and Mollendo. Philippi -Angulo, a native of Taurisma, a town above Cotahuasi, acted as majordomo -on this journey. Knowing the trail and the camp sites, I was able to -pick out the stations ahead myself, and made good progress, returning to -Cotahuasi on October 29th, three or four days earlier than planned. From -Cotahuasi to the coast I had the assistance of Mr. Watkins. The most -trying part of the last section of high altitude country was the great -Pampa Colorada, crowned by the snow-capped peaks of Solimana and -Coropuna, reaching heights of 20,730 and 21,703 feet respectively. The -passing of this pampa took seven days and we arrived at Chuquibamba on -November 9th. Two circumstances made the work on this stretch peculiarly -difficult--the scarcity of camping places and the high temperature in -the middle of the day, which heated the rarefied air to a degree that -made long-distance shots very strenuous work for the eyes. Although our -base signals were stone piles higher than a man, I was often forced to -keep my eye to the telescope for hours to catch a glimpse of the -signals; lack of time did not allow me to stop the telescope work in the -hottest part of the day. - -The top of Coropuna was intersected from the four stations: 16,344, -15,545, 16,168, and 16,664 feet elevation, the intersections giving a -very small triangular error. The elevation of Mount Coropuna’s high peak -as computed from these 4 stations is: - - 21,696 feet - 21,746 " - 21,714 " - 21,657 " - ------ - Mean elevation 21,703 feet above sea level. - -The elevation of Coropuna as derived from these four stations has thus a -mean error of 18 feet (method of least squares) while the elevation of -each of the four stations as carried up from mean sea level through 25 -stations--vertical angles being observed in both directions--has an -estimated mean error of 30 feet. The result of this is a mean error of -35 feet in Coropuna’s elevation above mean sea level. - -The latitude is 15° 31′ 00″ S.; the longitude is 72° 42′ 40″ W. of -Greenwich, the checking of these two determinations giving a result -unexpectedly close. - -On November 11th azimuth and latitude observations were taken at -Chuquibamba and two days later we arrived at Aplao in the bottom of the -splendid Majes Valley. In the northern part of this valley I was -prevented from doing any plane-table work in the afternoons of four -successive days. A strong gale set in each noon raising a regular -sandstorm, that made seeing almost impossible, and blowing with such a -velocity that it was impossible to set up the plane-table. - -From Hacienda Cantas to Camaná we had to pass the western desert for a -distance of 45 miles. We were told that on the entire distance there was -only one camping place. This was at Jaguey de Majes, where there was a -brook with just enough water for the animals but no fodder. Thus we -faced the necessity of carrying water for ten men and fodder for 14 -animals in excess of the usual cargo; and we were unable to foretell how -many days the topography over the hot desert would require. - -Although plane-table work in the desert was impossible at all except in -the earliest and latest hours of the day, we made regular progress. We -camped three nights at Jaguey and arrived on the fourth day at Las -Lomas. - -The next morning, on November 23rd, at an elevation of 2178 feet near -the crest of the Coast Range, we were repaid for two months of laborious -work by a glorious view of the Pacific Ocean and of the city of Camaná -with her olive gardens in the midst of the desert sand. - -The next day I observed latitude and azimuth at Camaná and in the night -my companion and assistant Mr. Watkins and I returned across the desert -to the railroad at Vitor. - - -CONCLUSIONS - -The planned methods were followed very closely. In two cases only the -plane-table had to be oriented by the magnetic needle, the backsights -not being obtainable because of the impossibility of locating the last -station, passing Indians having removed the signals. - -In one case only the distance between two stations had to be determined -by graphic triangulation exclusively, the base signals having been -destroyed. Otherwise graphic triangulation was used as a check on -distances. - -Vertical angles were always measured in both directions with the -exception of the above-mentioned cases. - -Observations for azimuth were always taken to the sun before and after -noon. The direction used in the azimuth observation was also taken with -the prismatic compass. The mean of the magnetic declination thus found -is: East 8° 30′ plus. - -Observations for latitude were taken to the sun by the method of -circum-meridian altitudes, except at the town of Vilcabamba where star -observations were taken. - -As a matter of course, observations to the sun are not so exact as star -observations, especially in low latitudes where one can expect to -observe the near zenith. However, working in high altitudes for long -periods, moving camp every day and often arriving at camp 2 to 4 hours -after sunset, I found it essential to have undisturbed rest at night. It -was beyond my capacity to spend an hour or two of the night in finding -the meridian and in making the observation. Furthermore, the astronomic -observations were to check the topography mainly, the latter being the -most exact method with the outfit at hand. - -The following table contains the comparisons between the latitude -stations as located on the map and by observation: - - Map Observation - Camaná Quadrangle S 16° 37′ 34″ 16° 37′ 34″[66] - Coropuna, station 9,691S 15° 48′ 30″ (15° 51′ 44″) - Cotahuasi, " 12,588S 15° 11′ 40″ 15° 12′ 30″ - La Cumbre, " 16,852S 14° 28′ 10″ 14° 29′ 46″ - Lambrama, " 8,341S 13° 43′ 18″ 13° 43′ 14″ - -The other observations, with the exception of the one on the Coropuna -Quadrangle, check probably as well as can be expected with the small and -light outfit which we used, and under the exceptionally hard conditions -of work. The observation on the Coropuna Quadrangle just south of -Chuquibamba is, however, too much out. An explanation for this is that -the meridian zenith distance was 1° 23′ 12″ only (in this case the exact -formula was used in computing). Of course, an error or an accumulation -of errors might have been made in the distances taken by the -micrometer-alidade, but the first cause of error mentioned is the more -probable, and this is indicated also by the fact that the location on -the top of Mount Coropuna checks closely with the one determined in an -entirely independent way by the railroad engineers. - -For the cross-section map from Abancay to Camaná, the following -statistics are desirable: - -Micrometer traverse and graphic triangulation, with contours, field -scale 1:90,000. - - Total time required, days 40.5 - Average distance per days in miles 7.5 - Average number of plane-table stations occupied per day 1.5 - Average area per day in square miles 38. - Located points per square mile 0.25 - Approximate elevations in excess of above, per square mile 0.25 - Highest station occupied, feet above sea level 17,675. - Highest point located, feet above sea level 21,703. - - - - -APPENDIX B - -FOSSIL DETERMINATIONS - - -A few fossil collections were gathered in order that age determinations -might be made. With the following identifications I have included a few -fossils (I and II) collected by W. R. Rumbold and put into my hands in -1907. The Silurian is from a Bolivian locality south of La Paz but in -the great belt of shales, slates, and schists which forms one of the -oldest sedimentary series in the Eastern Andes of Peru as well as -Bolivia. While no fossils were found in this series in Peru the rocks -are provisionally referred to the Silurian. Fossil-bearing Carboniferous -overlies them but no other indication of their age was obtained save -their general position in the belt of schists already mentioned. I am -indebted to Professor Charles Schuchert of Yale University for the -following determinations. - - -I. _Silurian_ - - San Roque Mine, southwest slope of Santa Vela Cruz, Canton Ichocu, Province - Inquisivi, Bolivia. - - Sent by William R. Rumbold in 1907. - - _Climacograptus?_ - _Pholidops trombetana_ Clarke? - _Chonetes striatellus_ (Dalman). - _Atrypa marginalis_ (Dalman)? - _CÅ“lospira_ n. sp. - _Ctenodonta_, 2 or more species. - _Hyolithes._ - _KlÅ“denia._ - _Calymene?_ - _Dalmanites_, a large species with a terminal tail spine. - _Acidaspis._ - -These fossils indicate unmistakably Silurian and probably Middle -Silurian. As all are from blue-black shales, brachiopods are the rarer -fossils, while bivalves and trilobites are the common forms. The faunal -aspect does not suggest relationship with that of Brazil as described by -J. M. Clarke and not at all with that of North America. I believe this -is the first time that Silurian fossils have been discovered in the high -Andes. - - -II. LOWER DEVONIAN - -Near north end of Lake Titicaca. - - _LeptocÅ“lia flabellites_ (Conrad), very common. - _Atrypa reticularis_ (Linnæus)? - -This is a part of the well-known and widely distributed Lower Devonian -fauna of the southern hemisphere. - - -III. _Upper Carboniferous_ - -All of the Upper Carboniferous lots of fossils represent the well-known -South American fauna first noted by d’Orbigny in 1842, and later added -to by Orville Derby. The time represented is the equivalent of the -Pennsylvanian of North America. - -Huascatay between Pasaje and Huancarama. - - Crinoidal limestone. - Trepostomata Bryozoa. - _Polypora._ Common. - _Streptorhynchus hallianus_ Derby. Common. - _Chonetes glaber_ Geinitz. Rare. - _Productus humboldti_ d’Orb. Rare. - " _cora_ d’Orb. Rare. - " _chandlessii_ Derby. - " sp. undet. Common. - " sp. undet. " - _Spirifer condor_ d’Orb. Common. - _Hustedia mormoni_ (Marcou). Rare. - _Seminula argentea_ (Shepard). " - - Pampaconas, Pampaconas valley near Vilcabamba. - - _Lophophyllum?_ - _Rhombopora_, etc. - _Productus._ - _Camarophoria._ Common. - _Spirifer condor_ d’Orb. - _Hustedia mormoni_ (Marcou). - _Euomphalus._ Large form. - - Pongo de Mainique. Extreme eastern edge of Peruvian Cordillera. - - _Lophophyllum._ - _Productus chandlessii_ Derby. - " _cora_ d’Orb. - _Orthotetes correanus_ (Derby). - _Spirifer condor_ d’Orb. - - River bowlders and stones of Urubamba river, just beyond eastern edge of - Cordillera at mouth of Ticumpinea river. (Detached and transported by stream - action from the Upper Carboniferous at Pongo de Mainique.) - - Mostly Trepostomata Bryozoa. - Many _Productus_ spines. - _Productus cora_ d’Orb. - _Camarophoria_. Same as at Pampaconas. - _Productus_ sp. undet. - - Cotahuasi A. - - _Lophophyllum._ - _Productus peruvianus_ d’Orb. - " sp. undet. - _Camarophoria._ - _Pugnax_ near _utah_ (Marcou). - _Seminula argentea_ (Shepard)? - - Cotahuasi B. - - _Productus cora_ d’Orb. - " near _semireticulatus_ (Martin). - - - IV. _Comanchian or Lower Cretaceous_ - - Near Chuquibambilla. - - _Pecten_ near _quadricostatus_ Sowerby. - Undet. bivalves and gastropods. - The echinid _Laganum? colombianum_ d’Orb. A clypeasterid. - -This Lower Cretaceous locality is evidently of the same horizon as that -of Colombia illustrated by d’Orbigny in 1842 and described on pages -63-105. - - - - -APPENDIX C - -KEY TO PLACE NAMES - - -Abancay, town, lat. 12° 35′, Figs. 20, 204. - -Abra Tocate, pass, between Yavero and Urubamba valleys, - leaving latter at Rosalina, (Fig. 8). - _See also_ Fig. 55. - -Anta, town, lat. 13° 30′, Fig. 20. - -Antabamba, town, lat. 14° 20′, Figs. 20, 204. - -Aplao, town, lat. 16°, Figs. 20, 204. - -Apurimac, river, Fig. 20. - -Arequipa, town, lat. 16° 30′, Fig. 66. - -Arica, town, northern Chile, lat. 18° 30′. - -Arma, river, tributary of Apurimac, lat. 13° 25′, (Fig. 20); - tributary of Ocoña, lat. 15° 30′, (Fig. 20). - -Arma, village, lat. 13° 15′, Fig. 20. - _See also_ Fig. 140. - -Auquibamba, hacienda, lat. 13° 40′, Fig. 204. - - -Callao, town, lat. 12°, Fig. 66. - -Camaná, town, lat. 16° 40′, Figs. 20, 66, 204. - -Camisea, river, tributary of Urubamba entering from right, lat. 11° 15′. - -Camp 13, lat. 14° 30′. - -Cantas, hacienda, lat. 16° 15′, Fig. 204. - -Caraveli, town, lat. 16°, Fig. 66. - -Catacaos, town, lat. 5° 30′, Fig. 66. - -Caylloma, town and mines, lat. 15° 30′, Fig. 66. - -Caypi, village, lat. 13° 45′. - -Central Ranges, lat. 14°, Fig. 20. - _See also_ Fig. 157. - -Cerro Azul, town, lat. 13°, Fig. 66. - -Chachani, mt., overlooking Arequipa, lat. 16° 30′, (Fig. 66). - -Chaupimayu, river, tributary of Urubamba entering at Sahuayaco, _q.v._ - -Chili, river, tributary of Vitor River, lat. 16° 30′, (Fig. 66). - -Chinche, hacienda, Urubamba Valley above Santa Ana, lat. 13°, (Fig. 20). - -Chira, river, lat. 5°, Fig. 66. - -Choclococha, lake, lat. 13° 30′, Figs. 66, 68. - -Choqquequirau, ruins, canyon of Apurimac above junction of Pachachaca - River, lat. 13° 25′, (Fig. 20). - -Choquetira, village, lat. 13° 20′, Fig. 20. - _See also_ Fig. 136. - -Chosica, village, lat. 12°, Fig. 66. - -Chuquibamba, town, lat. 15° 50′, Figs. 20, 204. - -Chuquibambilla, village, lat. 14°, Figs. 20, 204. - -Chuquito, pass, Cordillera Vilcapampa between Arma and Vilcabamba - valleys, lat. 13° 10′, (Fig. 20). - _See also_ Fig. 139. - -Coast Range, Figs. 66, 204. - -Cochabamba, city, Bolivia, lat. 17° 20′, long. 66° 20′. - -Colorada, pampa, lat. 15° 30′, Fig. 204. - -Colpani, village, lower end of Canyon of Torontoy (Urubamba River), - lat. 13° 10′. _See_ Fig. 158. - -Copacavana, village, Bolivia, lat. 16° 10′, long. 69° 10′. - -Coribeni, river, lat. 12° 40′, Fig. 8. - -Coropuna, mt., lat. 15° 30′, Figs. 20, 204. - -Corralpata, village, Apurimac Valley near Incahuasi. - -Cosos, village, lat. 16°, Fig. 204. - -Cotabambas, town, Apurimac Valley, lat. 13° 45′, (Fig. 20). - -Cotahuasi, town, lat. 15° 10′, Figs. 20, 204. - -Cuzco, city, lat. 13° 30′, Fig. 20. - - -Echarati, hacienda, on the Urubamba River between Santa Ana and - Rosalina, lat. 12° 40′. - _See_ inset map, Fig. 8, _and also_ Fig. 54. - - -Huadquiña, hacienda, Urubamba River above junction with Vilcabamba, - lat. 13° 10′, (Fig. 20). - _See also_ Fig. 158. - -Huadquirca, village, lat. 14° 15′, Figs. 20, 204. - -Huaipo, lake, north of Anta, lat. 13° 25′, (Fig. 20). - -Huambo, village, left bank Pachachaca River between Huancarama - and Pasaje, lat. 13° 35′, (Fig. 20). - -Huancarama, town, lat. 13° 40′, Fig. 20. - -Huancarqui, village, lat. 16° 5′, Fig. 204. - -Huascatay, village, left bank of Apurimac above Pasaje, - lat. 13° 30′, (Fig. 20). - -Huaynacotas, village, lat. 15° 10′, Fig. 204. - -Huichihua, village, lat. 14° 10′, Fig. 204. - - -(Tablazo de) Ica, plateau, lat. 14°-15° 30′, Fig. 66. - -Ica, town, lat. 14°, Figs. 66, 67. - -Incahuasi, village, lat. 13° 20′, Fig. 20. - -Iquique, town, northern Chile, lat. 20° 15′. - -(Pampa de) Islay, south of Vitor River, (Fig. 66). - - -Jaguey, village, Pampa de Sihuas, _q.v._ - - -La Joya, pampa, station on Mollendo-Puno R.R., 16° 40′, (Fig. 66). - -Lambrama, village, lat. 12° 50′, Fig. 20. - -Lima, city, lat. 12°, Fig. 66. - - -Machu Picchu, ruins, gorge of Torontoy, _q.v._, lat. 13° 10′. - -Majes, river, Fig. 204. - -Manugali, river, tributary of Urubamba entering from left - above Puviriari River, lat. 12° 20′, (Fig. 8). - -Maritime Cordillera, Fig. 204. - -Matara, village, lat. 14° 20′, Fig. 204. - -(El) Misti, mt., lat. 16° 30′, Fig. 66. - -Mollendo, town, lat. 17°, Fig. 66. - -Moquegua, town, lat. 17°, Fig. 66. - -Morococha, mines, lat. 11° 45′, Fig. 66. - -Mulanquiato, settlement, lat. 12° 10′, Fig. 8. - - -Occobamba, river, uniting with Yanatili, _q.v._ - -Ocoña, river, lat. 15°-16° 30′, Figs. 20, 66. - -Ollantaytambo, village. Urubamba River below Urubamba town, - lat. 13° 15′, (Fig. 20), _and see_ inset map, Fig. 8. - - -Pabellon, hacienda, Urubamba River above Rosalina, (Fig. 20). - _See also_ Fig. 55. - -Pacasmayo, town, lat. 7° 30′, Fig. 66. - -Pachatusca (Pachatusun), mt., overlooking Cuzco to northeast, lat. 13° 30′. - -Pachitea, river, tributary of Ucayali entering from left, lat. 8° 50′. - -Paita, town, lat. 5°, Fig. 66. - -Pampacolea, village, south of Coropuna, _q.v._ - -Pampaconas, river, known in lower course as Cosireni, - tributary of Urubamba River, (Fig. 8). - Source in Cordillera Vilcapampa west of Vilcabamba. - -Pampas, river, tributary of Apurimac entering from left, lat. 13° 20′. - -Panta, mt., Cordillera Vilcapampa, northwest of Arma, lat. 13° 15′, (Fig. 20). - _See also_ Fig. 136. - -Panticalla, pass, Urubamba Valley above Torontoy, lat. 13° 10′. - -Pasaje, hacienda and ferry, lat. 13° 30′, Fig. 20. - -Paucartambo (Yavero), river, _q.v._ - -Paucartambo, town, head of Paucartambo (Yavero) River, - lat. 13° 20′, long. 71° 40′. Inset map, Fig. 8. - -Pichu-Pichu, mt., overlooking Arequipa, lat. 16°, (Fig. 66). - -Pilcopata, river, tributary of Upper Madre de Dios - east of Paucartambo, lat. 13°. - -Piñi-piñi, river, tributary of Upper Madre de Dios - east of Paucartambo, lat. 13°. - -Pisco, town, lat. 14°, Fig. 66. - -Piura, river, lat. 5°-6°, Fig. 66. - -Piura, town, lat. 5° 30′, Fig. 66. - -Pomareni, river, lat. 12°, Fig. 8. - -Pongo de Mainique, rapids, lat. 12°, Fig. 8. - -Pucamoco, hacienda, Urubamba River, between Santa Ana and Rosalina, (Fig. 20). - -Puquiura, village, lat. 13° 5′, Fig. 20. - _See also_ Fig. 158. Distinguish Puqura in Anta basin near Cuzco. - -Puqura, village, Anta basin, east of Anta, lat. 13° 30′, (Fig. 20). - - -Quilca, town, lat. 16° 40′, Fig. 66. - -Quillagua, village, northern Chile, lat. 21° 30′, long. 69° 35′. - - -Rosalina, settlement, lat. 12° 35′, Fig. 8. - _See also_ Fig. 20. - - -Sahuayaco, hacienda, Urubamba Valley above Rosalina, (Fig. 20). - _See also_ Fig. 55. - -Salamanca, town, lat. 15° 30′, Fig. 20. - -Salaverry, town, lat. 8°, Fig. 66. - -Salcantay, mt., lat. 13° 20′, Fig. 20. - -San Miguel, bridge, canyon of Torontoy near Machu Picchu, lat. 13° 10′. - -Santa Ana, hacienda, lat. 12° 50′, Fig. 20. - -Santa Ana, river, name applied to the Urubamba in the - region about hacienda Santa Ana. - -Santa Lucia, mines, lat. 16°, Fig. 66. - -Santo Anato, hacienda, La Sama’s hut, 12° 35′, Fig. 8. - -Sihuas, Pampa de, lat. 16° 30′, Fig. 204. - -Sillilica, Cordillera, east of Iquique, northern Chile. - -Sintulini, rapids of Urubamba River above junction of - Pomareni, lat. 12° 10′, (Fig. 8). - -Sirialo, river, lat. 12° 40′, Fig. 8. - -Soiroccocha, mt., Cordillera Vilcapampa north of Arma, - lat. 13° 15′, (Fig. 20). - -Solimana, mt., lat. 15° 20′, Fig. 204. - -Soray, mt., Cordillera Vilcapampa, southeast of Mt. Salcantay, - lat. 13° 20′, (Fig. 20). - -Sotospampa, village, near Lambrama, lat. 13° 50′, (Fig. 204). - -Sullana, town, Chira River, lat. 5°, (Fig. 66). - - -Taurisma, village, lat. 15° 10′, Fig. 204. - -Ticumpinea, river, tributary of Urubamba entering from right - below Pongo de Mainique, lat. 11° 50′, (Fig. 8). - -Timpia, river, tributary of Urubamba entering from right, lat. 11° 45′. - -Tono, river, tributary of Upper Madre de Dios, east of Paucartambo, lat. 13°. - -Torontoy, canyon of the Urubamba between the villages of Torontoy - and Colpani, lat. 13° 10′-13° 15′. - -Torontoy, village at the head of the canyon of the same name, lat. 13° 15′. - _See_ inset map, Fig. 8. - -Tumbez, town, lat. 4° 30′, Fig. 66. - -Tunari, Cerro de, mt., northwest of Cochabamba, _q.v._ - - -Urubamba, river, Fig. 20. - -Urubamba, town, lat. 13° 20′, Fig. 20. - - -Vilcabamba, river, tributary of Urubamba River entering from - left above Santa Ana, lat. 13°, Fig. 8. - _See also_ Fig. 158. - -Vilcabamba, village, lat. 13° 5′, Fig. 20. - _See also_ Fig. 158. - -Vilcanota, Cordillera, southern Peru. - -Vilcanota, river, name applied to Urubamba above lat. of - Cuzco, 13° 30′, (Fig. 20). - -Vilcapampa, Cordillera, lat. 13° 20′, Fig. 20. - -Vilque, town, southern Peru, lat. 15° 50′, long. 70° 30′. - -Vitor, pampa, lat. 16° 30′, Fig. 66. - -Vitor, river, Fig. 66. - - -Yanahuara, pass, between Urubamba and Yanatili valleys, lat. 13° 10′. - -Yanatili, river, tributary of Urubamba entering from right - above Rosalina, (Fig. 20). - _See also_ Fig. 65. - -Yavero (Paucartambo), river, tributary of Urubamba entering - from right, lat. 12° 10′, Fig. 8. - -Yavero, settlement, at junction of Yavero and Urubamba - rivers, lat. 12° 10′, Fig. 8. - -Yunguyo, town, southern Peru, lat. 16° 20′, long. 69° 10′. - -Yuyato, river, lat. 12° 5′, Fig. 8. - - - - -INDEX - - -Abancay, 32, 62, 64, 78, 92, 93, 181, 189, 221, 243; - suppressing a revolution, 89-91; - temperature curve (diagr.), opp. p. 180 - -Abancay basin, 154 - -Abancay to Camaná cross-section map, work, observation and statistics, 315 - -Abra Tocate, 73, 80, 81; - topography and vegetation from (ill.), opp. p. 19 - -Abra de Malaga, 276 - -Acosta, 205 - -Adams, G. I., 255 - -Agriculture, 74-76, 152 - -Aguardiente, 74. _See_ Brandy - -Alcohol, 5, 6 - -Alluvial fans, 60-63, 70, 270 - -Alluvial fill, 270-273; - view in Majes Valley (ill.), opp. p. 230 - -Alpacas, 5, 52 - -Alto de los Huesos (ill.), opp. p. 7 - -Amazon basin, Humboldt’s dream of conquest, 33-35; - Indian tribes, 36 - -Amazonia, 20, 26 - -Ancachs, 171 - -Andahuaylas, 89 - -Andrews, A, C., 295 - -Angulo, Philippi, 317 - -Anta, 187, 189, 190 - -Anta basin, 62, 108, 197; - geology, 250; - view looking north from hill near Anta (ill.), opp. p. 184 - -Antabamba, 52, 53, 95, 96, 99, 101, 189, 197, 243, 303, 316; - Governor, 95-99, 100-101; - Lieutenant Governor, 96-99, 101; - sketch section, 243 - -Antabamba Canyon, view across (ill.), opp. p. 106 - -Antabamba Quadrangle, 316, opp. p. 282 (topog. sheet) - -Antabamba region, geologic sketch map and section, 245 - -Antabamba Valley, 96 - -“Antis,†39 - -Aplao, 106, 115, 116, 181, 226, 231, 255, 256, 257, 273, 318; - composite structure section (diagr.), 259; - temperature curve (diagr.), 181 - -Aplao Quadrangle (topog. sheet), opp. p. 120 - -Appendix A, 315 - -Appendix B, 321 - -Appendix C, 324 - -Apurimac, 51, 57, 60, 94, 153, 154; - crossing at Pasaje (ills.), opp. p. 91; - regional diagram of canyoned country, 58 - -Apurimac Canyon, 189; - cloud belt (ill.), opp. p. 150 - -Arequipa, 52, 89, 92, 117, 120, 137, 284; - glacial features near (sketches), 280 - -Argentina, 93 - -Arica, 130, 132, 198 - -Arma, 67, 189, 212-214 - -Arrieros, Pampa de, 280 - -Asymmetrical peaks (ill.), opp. p. 281 - -Asymmetry, 305-313; - cross-section of ridge (diagr.), 306; - postglacial volcano (diagr.), 306 - -Auquibamba, 93 - -Avalanches, 290 - - -Bailey, S. I., 284 - -Bandits, 95 - -Basins, 60, 154; - regional diagram, 61; - climatic cross-section (diagr.), 62 - -Batholith, Vilcapampa, 215-224 - -Belaunde brothers, 116 - -Bergschrunds, 294-305 - -Bingham, Hiram, ix, 104, 157 - -Block diagram of physiography of Andes, 186 - -Boatmen, Indian, 13 - -Bogotá, Cordillera of, 205 - -Bolivia, 93, 176, 190, 193, 195, 240, 241, 249, 322; - snowline, 275-277 - -Bolivian boundary, 68 - -Border valleys of the Eastern Andes, 68-87 - -Borneo, 206 - -Bowman, Isaiah, 8, 316 - -Brandy, 74, 75, 76, 82-83 - -Bravo, José, 245 - -Bumstead, A. H., ix - - -Cacao, 74, 83 - -Cacti, 150; - arboreal (ill.), opp. p. 90 - -Calchaquà Valley, 250 - -Callao, 118; - cloudiness (with diagr.), 133; - temperature (with diagr.), 126-129; - wind roses (diagrs.), 128 - -Camaná, 21, 112, 115, 116, 117, 118, 140-141, 147, 181, - 225, 226, 227, 266, 318; - coastal Tertiary, 253, 254; - plain of, 229; - temperature curve (diagr.), 181 - -Camaná Quadrangle (topog. sheet), opp. p. 114 - -Camaná Valley, 257 - -Camaná-Vitor region, 117 - -Camino del Peñon, 110 - -Camisea, 36 - -Camp 13, 100, 180, 181; - temperature curve (diagr.), 180 - -Campas, 37 - -Canals for bringing water, 59, 60, 155; - projected, Maritime Cordillera (diagr.), 118 - -Cantas, 115, 116, 226, 253, 257, 273, 318 - -Canyon walls (ills.), opp. p. 218 - -Canyoned country, regional diagram, 58; - valley climates (diagr.), 59 - -Canyons, 60, 72, 73, 197, 219; - Majes River (ill.), opp. p. 230; - topographic conditions before formation of deep - canyons in Maritime Cordillera (ill.), opp. p. 184 - -Caraveli, climate data, 134-136; - wind roses (diagrs.), 136 - -Carboniferous fossils, 323 - -Carboniferous strata, 241-247; - hypothetical distribution of land and sea (diagr.), 246 - -Cashibos, 37 - -Catacaos, 119 - -Cattle tracks (ill.), opp. p. 226 - -Caucho, 29 - -Caylloma, 164, 165 - -Caypi, 316 - -Central Ranges, asymmetrical peaks (ill.), opp. p. 281; - glacial features with lateral moraines (ill.), opp. p. 269; - glacial topography between Lambrama and Antabamba (ill.), opp. p. 280; - steep cirque walls (ill.), opp. p. 286 - -Cerro Azul, 118 - -Cerro de Tunari, 176 - -Chachani, 280, 284 - -Chanchamayo, 77 - -Character. _See_ Human character - -Chaupimayu Valley, 77 - -_Chicha_, 86 - -Chile, 130, 132, 193, 260 - -Chili River, 120 - -Chili Valley, opp. p. 7 (ill.), 117 - -Chimborazo, 281 - -Chinche, 271, 272 - -Chira River, depth diagram, 119, 120 - -Chirumbia, 12 - -Choclococha, Lake, 120 - -Chonta Campas, 37 - -Choqquequirau, 154 - -Choquetira, 66, 67, 211; - bowldery fill below, 269; - glacial features, 206-207 - -Choquetira Valley, moraine, (ill.), opp. p. 208 - -Chosica, 136, 137; - cloudiness (diagr.), 138 - -_Chuño_, 57 - -Chuntaguirus, 41 - -Chuquibamba, 54, 72, 107, 110, 111, 112, 115, 116, 273, 317-319; - sediments, 258 - -Chuquibambilla, 53, 189, 220, 221, 222, 236, 243; - alluvial fill (diagr.), 272; - Carboniferous, 244; - fossils, 323 - -Chuquito pass, crossing (ill.), opp. p. 7; - glacial trough (ill.), opp. p. 205 - -Cirque walls, steep (ill.), opp. p. 286 - -Cirques, 294-305; - development (diagr.), 300; - development, further stages (diagr.), 301; - mode of formation (diagr.), 297 - -Clarke, J. M., 321 - -Clearing in forest (ill.), opp. p. 25 - -Climate, coast, 125-147; - eastern border, 147-153; - Inter-Andean valleys, 153-155; - _see also_ Meteorological records - -Climatic belts, 121-122; - map, 123 - -Climatology, 121-156 - -Cliza, 276 - -Cloud-banners, 16 - -Cloud belt, 143, opp, p. 150 (ill.) - -Cloudiness, 132; - Callao (with diagr.), 133; - desert station near Caraveli (diagrs.), 137; - Machu Picchu, 160; - Santa Lucia (diagr.), 169 - -Clouds, Inter-Andean Valley, 155; - Santa Ana (ill.), opp. p. 180; - Santa Lucia, 168; - types on eastern border of Andes (diagrs.), 148; - _see also_ Fog - -Coast Range, 111, 113, 114, 116, 118, 225-232; - climate, 122-147; - direction, 267; - diagram to show progressive lowering of saturation - temperature in a desert, 127; - geology, 258; - view between Mollendo and Arequipa in June (ill.), opp. p. 226; - wet and dry seasons (diagrs.), 132 - -Coastal belt, map of irrigated and irrigable land, 113 - -Coastal desert, 110-120; - regional diagram of physical relations, 112; - _see also_ Deserts - -Coastal planter, 6 - -Coastal region, topographic and climatic provinces (diagr.), 125 - -Coastal terraces, 225-232 - -Coca, 74, 77, 82-83 - -Coca seed beds (ill.), opp. p. 74 - -Cochabamba, 93; - temperature (diagrs. of ranges), insert opp. p. 178; - weather data, 176-178 - -Cochabamba Indians, 276 - -Colombia, 205 - -Colorada, Pampa de, 114, 317 - -Colpani, 72, 215, 216, 222, 223; - from ice to sugar cane (ill.), opp. p. 3 - -Comanchian fossils, 323 - -Cómas, 155 - -Compañia Gomera de Mainique, 29, 31, 32 - -Concession plan, 29 - -Conibos, 44 - -_Contador_, 84-85 - -Copacavana, 176 - -Cordilleras, 4, 6, 20, 197 - -Coribeni, 15 - -Corn, 57, 59, 62 - -Coropuna, 109, 110, 112, 202, 253, 317, 319; - elevation, 317; - glaciation, 307; - snowline, 283-285 - -Coropuna expedition, 104 - -Coropuna Quadrangle, 197, opp. p. 188 (topog. sheet), 319 - -Corralpata, 51, 59 - -Cosos, 231 - -Cotabambas, 78 - -Cotahuasi, 4, 5, 52, 54, 60, 97, 101, 103, 104, 180, 197, 199, 316, 317; - alluvial fill, 272; - fossils, 322; - geologic sketch maps and cross-section, 247; - rug weaver (ill.), opp. p. 68; - snowline above, 282-283; - temperature curve (diagr.), 180; - view (ill.), opp. p. 57 - -Cotahuasi Canyon, 247, 248, 316 - -Cotahuasi Quadrangle (topog. sheet), opp. p. 192 - -Cotahuasi Valley, geology, 258 - -Cotton, 76, 116, 117 - -Crest lines, asymmetrical, 305-313 - -Cretaceous formations, 247-251 - -Cretaceous fossils, 323 - -Crucero Alto, 188 - -Cuzco, 8, 10, 21, 52, 62, 63, 92, 102, 107, 193, 197; - railroad to Santa Ana, 69-70; - snow, 276; - view (ill.), opp. p. 66 - -Cuzco basin, 61, 62, 154, 251; - slopes at outlet (diagr.), 185 - - -Deformations. _See_ Intrusions - -Derby, Orville, 322 - -Desaguadero Valley, 193 - -Deserts, cloudiness (diagrs.), 137; - rain, 138-140; - sea-breeze in, 132; - tropical forest, 36-37; - wind roses (diagrs.), 136 - -Diagrams. _See_ Regional diagrams - -Dikes, 223 - -Drunkenness, 103, 105-106, 108 - -Dry valleys, 114-115 - -Dunes, 114, 254; - Majes Valley, 262-267; - movement, 132; - superimposed (diagrs.), 265 - -Duque, Señor, 78 - - -Eastern Andes, 204-224; - regional diagram, 22 - -Eastern border, climate, 147-153 - -Eastern valley planter, 3 - -Eastern valleys, 68-87; - climate cross-section (diagr.), 79 - -Echarati, 10, 77, 78, 80, 82; - plantation scene (ill.), opp. p. 75 - -Ecuador volcanoes, 281 - -Epiphyte (ill.), opp. p. 78 - -Erdis, E. C., 158 - -Erosion, 192-195, 210, 211, 305; - _see also_ Glacial erosion; Nivation - -Erving, Dr. W. G., 13, 101, 316, 317 - - -_Faena_ Indians, 75, 83-87 - -Feasts and fairs, 175-176 - -Ferries, 147 - -Fig tree (ill.), opp. p. 75 - -Floods, 151 - -Fog, 132, 139, 143; - conditions along coast from Camaná to Mollendo, 144-145; - _see also_ Clouds - -Forest dweller, 1 - -Forest Indians. _See_ Machigangas - -Forests, clearing (ill.), opp. p. 25; - dense ground cover, trees, epiphytes, and parasites (ill.), opp. p. 155; - moss-draped trees (ill.), opp. p. 24; - mountain, 148-153; - mule trail (ill.), opp. p. 18; - tropical, near Pabellon (ill.), opp. p. 150; - tropical vegetation (ill.), opp. p. 18; - type at Sahuayaco (ill.), opp. p. 90 - -Fossils, 245, 321; - list of, by geologic periods and localities, 321 - -Frankland, 278, 309 - -Frost line, 56-57 - - -Garua, 132 - -Geographical basis of revolutions and of human character, 88-109 - -Geologic dates, 195-196; - Majes Valley, 258, 261; - west coast fault, 248-249 - -Geologic development. _See_ Physiographic and geologic development - -Gilbert, G. K., 300, 302, 305 - -Glacial deposits, 268 - -Glacial erosion, Central Andes, 305-313; - composite sketch of general conditions, 312; - graphic representation of amount during glacial period, 311 - -Glacial features, 274-313; - Arequipa (sketches), 280; - Central Ranges; lateral moraines (ill.), opp. p. 269; - eastern slopes of Cordillera Vilcapampa (map), 210 - -Glacial retreat, 208-214 - -Glacial sculpture, heart of the Cordillera Vilcapampa (map), 212; - southwestern flank of Cordillera Vilcapampa (map), 207 - -Glacial topography between Lambrama and Antabamba (ill.), opp. p. 280; - Maritime Cordillera, north of divide on 73d meridian (ill.), opp. p. 281 - -Glacial trough, view near Chuquito pass (ill.), opp. p. 208 - -Glaciation, 64, 271; - Sierra Nevada, 305; - Vilcapampa, 204-214; - Western Andes, 202 - -Glaciers, Panta Mountain (ill.), opp. p. 287; - view (ill.), opp. p. 205 - -Gomara, 34 - -Gonzales, Señor, 78 - -Government, bad, 95 - -Gran Pajonal, 37 - -Granite, 215-224; - _see also_ Intrusions - -Grass (ill.), opp. p. 154 - -Gregory, J. W., 205 - - -_Hacendado_, 55, 60 - -_Haciendas_, 78, 83, 86 - -Hann, J., 126, 176, 278 - -Hendriksen, Kai, 98, 315 - -Hettner, 205 - -Hevea, 29 - -Highest habitations in the world, 52, 96; - regional diagram of, 50; - stone hut (ill.), opp. p. 48 - -Highland shepherd, 4 - -Highlands, 46 - -Hobbs, W. H., 286, 287 - -Horses, 66, opp. p. 91 (ill.) - -Huadquiña, 70, 71, 72, 75, 82, 86, 219; - hacienda (ill.), opp. p. 73; - terraces, 272 - -Huadquirca, 243 - -Huaipo, Lake, 250, 251 - -Huallaga basin, 153 - -Huambo, 243 - -Huancarama, 64, 87, 189, 243, 303; - view (ill.), opp. p. 106 - -Huancarqui, 257 - -Huari, 176 - -Huascatay, 189, 242, 243; - Carboniferous, 244; - fossils, 322 - -Huasco basin, 275 - -Huaynacotas, 103, 316; - terraced valley slope (ill.), opp. p. 56; - terraced valley slopes (ill.), opp. p. 199 - -Huichihua, 278; alluvial fill (diagr.), 272; - (ill.), opp. p. 67 - -Human character, geographic basis, 88-109 - -Humboldt, 33-35, 286 - -Humboldt Current, 126, 143 - -Huts, 103; - highest in Peru (ill.), opp. p. 48; - shepherds’, 47, 48, 52, 55 - - -Ica Valley, 120; - irrigated and irrigable land (diagr.), 118 - -Ice erosion. _See_ Glacial erosion - -Incahuasi, 51, 155, 285 - -Incas, 39, 44, 46, 62, 63, 68, 77, 109, 175 - -Incharate, 78 - -Indian boatmen, 13 - -Indians, as laborers, 26-28, 31-32; - basin type, 63-64; - forest, _see_ Machigangas; - life and tastes, 107-108; - mountain, 46-67, 101-102; - plateau, 40-41, 44-45, 100, 106-109; - troops, 90, 91; - wrongs, 14, 102 - -Ingomwimbi, 206 - -Instruments, surveying, 315 - -Inter-Andean valleys, climate, 153-155 - -Intermont basin. _See_ Basins - -Intrusions, deformations north of Lambrama (diagr.), 243; - deformative effects on limestone strata near Chuquibambilla (diagr.), 221; - lower Urubamba Valley (geologic sketch map), 237; - overthrust folds in detail near Chuquibambilla (diagr.), 222; - principles, 217-219 - -Intrusions, Vilcapampa, deformative effects near Puquiura (diagr.), 216; - relation of granite to schist near Colpani (with diagr.), 216 - -Iquique, wind roses (diagrs.), 131 - -Irrigation, 72, 76, 80, 82; - coastal belt (map), 113; - coastal desert, 119-120; - Ica Valley (diagr.), 118 - -Islay, Pampa de, 114 - -Italians, 18, 81 - - -Jaguey, 254, 255, 318 - -Jesuits, 68 - -Johnson, W. D., 213, 295, 296, 299, 300 - - -Kenia, Mt., 206, 274 - -Kerbey, Major, 8, 10 - -Kibo, 206, 274 - -Kilimandjaro, 205, 206 - -Kinibalu, 206 - -Krüger, Herr, 157 - - -Labor, 26-28, 31-32, 42-43, 74-75, 83-84 - -La Cumbre Quadrangle, 197, 202, opp. p. 202 (topog. sheet) - -La Joya, 132, 133; - cloudiness (diagr.), 134; - temperature curves (diagr.), 134; - wind roses (diagrs.), 135 - -Lambrama, 90, 92, 285, 316; - camp near (ill.), opp. p. 6 - -Lambrama Quadrangle (topog. sheet), opp. p. 304 - -Lambrama Valley, deformation types (diagr.), 243 - -Land and sea, Carboniferous hypothetical distribution - compared with present (diagr.), 246 - -Landscape, 183-198 - -Lanius, P. B., 13 - -La Paz, 93, 109, 276, 321 - -La Sama, 12, 13, 40 - -Las Lomas, 318 - -Lava flows, 199 - -Lava plateau, 197, 199, 307-308; - regional diagram of physical conditions, 55; - summit above Cotahuasi (ill.), opp, p. 204 - -Lavas, volume, 201 - -Lima, 92, 93, 118, 137, 138; - cloud, 132, 143; - temperature, 126 - -Limestone, sketch to show deformed, 243 - -Little, J. P., 135, 157 - -Llica, 275 - -Lower Cretaceous fossils, 323 - -Lower Devonian fossils, 321 - - -Machigangas, 10, 11, 12, 14, 18, 19, 31, 36-45, 81; - ornaments and fabrics (ill.), opp. p. 27; - trading with (ill.), opp. p. 26 - -Machu Picchu, 72, 220; - weather data (with diagr.), 158-160 - -Madeira-Mamoré railroad, 33 - -Madre de Dios, 1, 2, 33 - -Majes River, 147, 225, 227, 266, 267; - Canyon (ill.), opp. p. 230 - -Majes Valley, 106, 111, 116, 117, 120, 226, 227, 229-231, 318; - alluvial fill, 273; - date of formation, 258, 261; - desert coast (ill.), opp. p. 110; - dunes, 262-267; - erosion and uplift, 261; - lower and upper sandstones (ill.), opp. p. 250; - sediments, 255; - snowline, 283; - steep walls and alluvial fill (ill.), opp. p. 230; - structural details near Aplao (sketch section), 255; - structural details on south wall near Cantas (sketch section), 257; - structural relations at Aplao (field sketch), 256; - Tertiary deposits, 253-254; - wind, 130; - view below Cantas (ill.), opp. p. 110; - view down canyon (ill.), opp. p. 144 - -Malaria, 14, 38 - -Marañon, 41, 59 - -Marcoy, 79 - -Marine terrace at Mollendo (ill.), opp. p. 226 - -Maritime Cordillera, 52, 199-203, 233; - asymmetry of ridges, 308-309; - glacial features, 307; - glacial topography north of divide on 73d meridian (ill.), opp. p. 281; - pre-volcanic topography, 200; - post-glacial volcano, asymmetrical (diagr.), 306; - regional diagrams, 50, 52; - test of explanation of cirques, 303; - volcanoes, tuffs, lava flows (ill.), opp. p. 204; - western border rocks (geologic section), 257; - _see also_ Lava plateau - -Matara, 99, 316 - -Matthes, F. E., 286, 287, 289 - -Mature slopes, 185-193; between Ollantaytambo and Urubamba - (ill.), opp. p. 185; - dissected, north of Anta (ill.), opp. p. 185 - -Mawenzi, 206 - -Meanders, 16, 17 - -Médanos, 114 - -Mendoza, Padre, 11 - -Mer de Glace, 203 - -Meteorological records, 157-181 - -Mexican revolutions, 93 - -Middendorf, 143 - -Miller, General, 41, 78, 147 - -Minchin, 241 - -Misti, El, opp. p. 7 (ill.), 284 - -Molina, Christoval de, 175 - -Mollendo, 93, 105, 117; - cloud belt, 143; - cloudiness (diagr.), 134; - coastal terraces, 225; - humidity, 133; - marine terrace (ill.), opp. p. 226; - profile of coastal terraces (diagr.), 227; - temperature curves (diagr.), 134; - wind roses (diagrs.), 129 - -Mollendo-Arequipa railroad, 117 - -Mollendo rubber, 32 - -Montaña, 148, 149, 153 - -Moquegua, 117; - geologic relations (diagr.), 255 - -Moraines, 207, 210-211; - Choquetira Valley (ill.), opp. p. 208; - view (ill.), opp. p. 208 - -Morales, Señor, 11 - -Morococha, temperature (diagrs. of ranges), insert opp. p. 172; - weather data (with diagrs.), 171-176 - -Morococha Mining Co., 157, 171 - -Morro de Arica, 132 - -Moss, large ground. _See Yareta_ - -Moss-draped trees (ill.), opp. p. 24 - -Mountain-side trail (ill.), opp. p. 78 - -Mountains, tropical, as climate registers, 206 - -Mulanquiato, 10, 18, 19 - -Mule trail (ill.), opp. p. 18 - -Mules, 23, 24, 94, opp. p. 91 (ill.) - - -Névé, 286-305 - -Niño, El, 137-138 - -Nivation, 285-294; - “pocked†surface (ill.), opp. p. 286 - -Northeastern border, topographic and structural section (diagr.), 241 - - -Occobamba Valley, 79 - -Ocean currents of adjacent waters, 121-122 (map), 123 - -Ollantaytambo, 70, 73, 75, 250, 271; - terraced valley floor (ill.), opp. p. 56 - -d’Orbigny, 322 - -Oruro, 93 - - -Pabellon, 80, 82, opp. p. 150 - -Pacasmayo, Carboniferous land plants, 245 - -Pachitea, 37, 38 - -Pacific Ocean basin, 248 - -Paleozoic strata (ill.), opp. p. 198 - -_Palma carmona_, 29 - -Palmer, H. S., 250 - -Paltaybamba, opp. p. 74 - -Pampacolca, 109 - -Pampaconas, 69, 211, 213, 215; - rounded slopes near Vilcabamba (ill.), opp. p. 72; - Carboniferous, 244; - fossils, 322; - snow action, 291 - -Pampaconas River, 316 - -Pampas, 114, 198; - climate data, 134-136 - -Pampas, river, 189 - -Panta, mt., 214; - view, with glacier system (ill.), opp. p. 287 - -Pará rubber, 32 - -Pasaje, 51, 57, 59, 60, 236, 238, 240, 241, 243; - Carboniferous, 244; - crossing the Apurimac (ills.), opp. p. 91 - -Paschinger, 274 - -Pastures, 141, 187; - Alpine (ill.), opp. p. 58 - -Paucartambo, 42, 77 - -Paucartambo River. _See_ Yavero River - -Payta, 225 - -Penck, A., 205 - -Peonage, 25, 27, 28 - -Pereira, Señor, 10, 18 - -Perene, 155 - -Physiographic and geologic development, 233-273 - -Physiographic evidence, value, 193-195 - -Physiographic principles, 217 - -Physiography, 183-186; - Southern Peru, summary, 197-198 - -Pichu-Pichu, 284 - -Piedmont accumulations, 260 - -Pilcopata, 36 - -Piñi-piñi, 36 - -Pisco, 130; - Carboniferous land plants, 247 - -Piura, 119 - -Piura River, depth diagram, 119, 120 - -Piura Valley, 48 - -Place names, key to, 324 - -Plantations, 86; - _see also_ Haciendas - -Planter, coastal, 6 - -Planters, valley, 3, 75, 76 - -Plateau Indians, 40-41, 44-45, 100, 106-109 - -Plateaus, 196-197 - -Pleistocene deposits, 267-273 - -Pomareni, 19 - -Pongo de Mainique, 8, 9, 11, 15-20, 40, 71, 179, 239, 241, 242, 273; - canoe in rapid above (ill.), opp. p. 11; - Carboniferous, 244; - dugout in rapids below (ill.), opp. p. 2; - fossils, 322; - temperature curve (diagr.), 178; - upper entrance (ill.), opp. p. 10; - vegetation, clearing, and rubber station (ill.), opp. p. 2 - -Poopó, 195 - -Potato field (ill.), opp p. 67 - -Potatoes, 57, 59, 62 - -PotosÃ, 249 - -Precipitation. _See_ Rain - -Profiles, composition of slopes and profiles (diagr.), 191 - -Pucamoco, 78 - -Pucapacures, 42 - -Puerto Mainique, 29, 30 - -Punas, 6, 197 - -Puquiura, 67, 87, 211, 216, 236, 238, 239, 243, 277; - Carboniferous, 244; - composition of slopes (ill.), opp. p. 198 - -Puqura, 250 - - -Quebradas, 145, 155 - -Quechuas, 44, 45, 77, 83 - -_Quenigo_, 285 - -Quilca, 105, 117, 226, 266 - -Quillabamba, opp. p. 74 - -Quillagua, 260 - - -Railroads, 74, 75, 76, 93, 101-102, 149; - Bolivia, 93; - Cuzco to Santa Ana, 69-70 - -Raimondi, 77, 78, 109, 110, 135, 155, 170, 316 - -Rain, 115, 119, 120, 122, 124-125; - coast region seasonal variation, 131-137; - eastern border of Andes, belts (diagrs.), 148; - effect of heavy, 138-140; - effect of sea-breeze, 131-132; - heaviest, 147-148; - Morococha (with diagrs.), 173-176; - periodic variations, 137; - Santa Lucia (with diagrs.), 164-166; - unequal distribution in western Peru, 145-147 - -Regional diagrams, 50; - index map, 23; - note on, 51 - -Regions of Peru, 1, 7 - -Reiss, 205, 208 - -Revolutions, geographic basis, 88-109 - -Rhone glacier, 205 - -Rice, 76 - -Robledo, L. M., 9, 30, opp. p. 78 - -Rock belts, outline sketch along 73d meridian, 235 - -Rocks, Maritime Cordillera, pampas and Coast Range structural - relations (sketch section), 254; - Maritime Cordillera, western border (geologic section), 257; - Moquegua, structural relations (diagr.), 255; - Urubamba Valley, succession (diagr.), 249 - -Rosalina, 8, 9, 10, 11, 37, 42, 71, 73, 80, 82, 153, 237 - -Rubber, 18; - price, 32, 33 - -Rubber forests, 22-35 - -Rubber gatherers, Italian, 18, 81 - -Rubber plant (ill.), opp. p. 75 - -Rubber trees, 152 - -Rueda, José, 78 - -Rug weaver (ill.), opp. p. 68 - -Rumbold, W. R., 321 - -Russell, I. C., 205 - -Ruwenzori, 206, 274 - - -Sacramento, Pampa del, 37 - -Sahuayaco, 77, 78, 80, 83, 179; - forests (ills.), opp. p. 90; - temperature curve (diagr.), 178 - -Salamanca, 54, 56, 105, 106, 180, 181; - forest, 285; - temperature curve (diagr.), 180; - terraced hill slopes (ill.), opp. p. 58; - view (ill.), opp. p. 107 - -Salaverry, 119 - -Salcantay, 64, 72, opp. p. 3 (ill.) - -San Geronimo, 276 - -Sand. _See_ Dunes - -“Sandy matico†(ill.), opp. p. 90 - -San Gabriel, Hacienda, 316 - -Santa Ana, 69, 72, 78, 79, 80, 82, 93, 153, 179, 237; - clouds (ill.), opp. p. 180; - temperature curve (diagr.), 178 - -Santa Ana Valley, 10, 82 - -Santa Lucia, temperature ranges (diagrs.), insert opp. p. 162; - unusual weather conditions, 169-170; - weather data (with diagrs.), 161-171 - -Santo Anato, 40, 42, 82, 179; - temperature curve (diagr.), 178 - -Schists and Silurian slates, 236-241 - -Schrund. _See_ Bergschrunds - -Schrundline, 300-305 - -Schuchert, Chas., 321 - -Sea and land. _See_ Land and sea - -Sea-breeze, 129-132 - -Shepherd, highland, 4 - -Shepherds, country of, 46-67 - -Shirineiri, 36, 38 - -Sierra Nevada, 305 - -Sierra Nevada de Santa Marta, 205 - -Sievers, W., 143, 176, 205, 263 - -Sihuas, Pampa de, 114, 198 - -Sillilica, Cordillera, 190, 260 - -Sillilica Pass, 275 - -Silurian fossils, 321 - -Silurian slates, 236-241 - -Sintulini rapids, 19 - -Sirialo, 8, 15 - -Slave raiders, 14 - -Slavery, 24, 25 - -Slopes, composition at Puquiura (ill.), opp. p. 198; - composition of slopes and profiles (diagr.), 191; - smooth grassy (ill.), opp. p. 79; - _see also_ Mature slopes - -Smallpox, 14, 38 - -Snow, 212; - drifting, 278; - fields on summit of Cordillera Vilcapampa (ill.), opp. p. 268 - -Snow erosion. _See_ Nivation - -Snow motion, curve of (diagr.), 293; - law of variation, 291 - -Snowline, 52, 53, 66, 122, 148, 203, 205-206, 274-285; - canting (with diagr.), 279; - determination, 282; - difference in degree of canting (diagr.), 281; - glacial period, 282; - view of canted, Cordillera Vilcapampa (ill.), opp. p. 280 - -Snowstorm, 170 - -Soiroccocha, 64, 72, 214; - view (ill.), opp. p. 154 - -Solimana, 4, 202, 317; - glaciation, 307 - -Soray, 64 - -Sotospampa, 243 - -South Pacific Ocean, 125 - -Spanish Conquest, 62, 63, 77 - -Spruce (botanist), 153 - -Steinmann, 249, 276 - -Streams, Coast Range, 145-147; - physiography, 192; - _see also_ Water - -Structure. _See_ Rocks - -Stübel, 209 - -Sucre, 93 - -Sugar, 73, 74, 75, 76, 82-83, 92 - -Sullana, 119 - -Survey methods employed in topographic sheets, 315 - - -Tablazo de Ica, 198 - -Tarai. _See_ Urubamba Valley - -Tarapacá, Desert of, 260 - -Tarapoto, 153 - -Taurisma, 317; - geologic sketch map and cross-section, 248 - -Taylor, Capt. A., 126, 128 - -Temperature, Abancay curve (diagr.), opp. p. 180; - Callao (with diagr.), 126-129; - Cochabamba, 176-178; - Cochabamba (diagrs. of ranges), insert opp. p. 178; - curves at various points along 73d meridian, 178-181; - La Joya curves (diagr.), 134; - Mollendo curves (diagr.), 134; - Morococha, 171-173; - Morococha (diagrs. of ranges), insert opp. p. 172; - progressive lowering of saturation, in a desert (diagr.), 127; - Santa Lucia, 161-164; - Santa Lucia (diagrs. of ranges), insert opp. p. 162 - -Tempests, 169-170 - -Terraces, coastal, 225-232; - physical history and physiographic development (with diagrs.), 228-230; - profile at Mollendo (diagr.), 227 - -Terraces, hill slopes (ill.), opp. p. 58 - -Terraces, marine (ill.), opp. p. 226 - -Terraces, valley (ills.), opp. p. 56, opp. p. 57, opp. p. 66; - Huaynacotas (ill.), opp. p. 199 - -_Terral_, 130 - -Tertiary deposits, 249, 251-267; - coastal, 253 - -Ticumpinea, 36, 38, 251 - -Tierra blanca, 254, 266 - -Timber line, 69, 71, 79, 148 - -Timpia, 36, 38, 252; - canoe at mouth (ill.), opp. p. 19 - -Titicaca, 161, 176, 195, 321 - -Titicaca basin, 107 - -Titicaca-Poopó basin, 251 - -Tocate. _See_ Abra Tocate - -_Tola_ bush (ill.), opp. p. 6 - -Tono, 36 - -Topographic and climatic cross-section (diagr.), opp. p. 144 - -Topographic and structural section of northeastern border - of Andes (diagr.), 241 - -Topographic map of the Andes between Abancay and the Pacific - Coast at Camaná, insert opp. p. 312 - -Topographic profiles across typical valleys (diagrs.), 189 - -Topographic regions, 121-122; - map, 123 - -Topographic sheets, survey method employed, 315; - list of, with page references, xi - -Topographical outfit, 315 - -Torontoy, 10, 70, 71, 72, 82, 158, 220 - -Torontoy Canyon, 272, opp. p. 3 (ill.); - cliff (ill.), opp. p. 10 - -Trail (mountain-side) (ill.), opp. p. 78 - -Transportation, 73-74, 93, 152; - rains and, 142 - -Trees, 150; - _see also_ Forests - -_Tucapelle_ (ship), 117 - -Tucker, H. L., ix - -Tumbez, 119 - -Tunari peaks, 276 - - -Ucayali, 42, 44 - -Uplift, recent, 190 - -Upper Carboniferous fossils, 322 - -Urubamba, 1, 41, 42, 62, 187; - village, 70, 73 - -Urubamba River, 72; - fossils, 322; - physiographic observations, 252-253; - rapids and canyons, 8-21; - shelter hut (ill.), opp. p. 11 - -Urubamba Valley, 72, 153, 238; - alluvial fans, 270; - alluvial fill, 272-273; - below Paltaybamba (ill.), opp. p. 74; - canyon walls (ill.), opp. p. 218; - dissected alluvial fans (sketch), 271; - floor from Tarai (ill.), opp. p. 70; - from ice to sugar cane (ill.), opp. p. 3; - geologic sketch map of the lower, 237; - line of unconformity of geologic structure (ill.), opp. p. 250; - rocks, 250; - rocks, succession (diagr.), 249; - sketch map, 9; - slopes and alluvial deposits between Ollantaytambo and Torontoy - (ill.), opp. p. 269; - temperature curves (diagrs.), 178-179; - terraced valley slopes and floor (ill.), opp. p. 66; - vegetation, distribution (ill.), opp. p. 79; - view below Santa Ana (ill.), opp. p. 155; - wheat and bread, 71 - - -Valdivia, Señor, 161 - -Vallenar, 49 - -Valley climates in canyoned region (diagr.), 59 - -Valley planters. _See_ Planters - -Valley profiles, abnormal, 305-313 - -Valleys, eastern; - _see_ Border valleys of the Eastern Andes; - _see also_ Dry valleys, Inter-Andean valleys; - topographic profiles across, typical in Southern Peru (diagrs.), 189 - -Vegetation, 141; - belts (map), 123; - distribution in Urubamba Valley (ill.), opp. p. 79; - shrubbery, mixed with grass (ill.), opp. p. 154; - Tocate pass (ill.), opp. p. 19; - _see also_ Forests - -Vicuña, 54 - -Vilcabamba, 66; - rounded slopes (ill.), opp. p. 72 - -Vilcabamba pueblo, 211, 277, 296 - -Vilcabamba Valley, 189 - -Vilcanota knot, 276 - -Vilcanota Valley, alluvial fill, 272 - -Vilcapampa, Cordillera, 15, 16, 22, 51, 53, 64, 66, 67, 197, 204-224, 233; - batholith and topographic effects, 215-224; - canted snowline (ill.), opp. p. 280; - climatic barrier, 73; - composite geologic section (diagr.), 215; - glacial features, 204-214; - glaciers, 304; - highest pass, crossing (ill.), opp. p. 7; - regional diagram, 65; - regional diagram of the eastern aspect, 68; - schrundline, 302; - snow movement, 287-289; - snow fields on summit (ill.), opp. p. 268; - snow peaks (ill.), opp. p. 72; - snowline, 277, 279; - southwestern aspect (ill.), opp. p. 205; - summit view (ill.), opp. p. 205 - -Vilcapampa Province, 77 - -Vilcapampa Valley, bowldery fill, 269 - -Vilque, 176 - -Violle, 309 - -_Virazon_, 130 - -Vitor, Pampa de, 114, 318 - -Vitor River, 92, 117, 226, 266, 267 - -Volcanic country, 199 - -Volcanic flows, geologic sketch, 244 - -Volcanoes, glacial erosion, 311; - post-glacial, 306-307; - recessed southern slopes (ill.), opp. p. 287; - snowline, 281; - typical form, 310; - views (ills.), opp. p. 204 - -Von Boeck, 176 - -Vulcanism, 199; - _see also_ Volcanoes - - -Ward, R. De C., 126, 143 - -Water, 59, 60, 116, 139; - projected canal from Atlantic to Pacific slope of the - Maritime Cordillera (diagr.), 118; - streams of coastal desert, intermittent and perennial, - diagrams of depth, 119 - -Water skippers, 17 - -Watkins, Mr., 317, 318 - -Weather. _See_ Meteorological records - -Western Andes, 199-203 - -Whymper, 205 - -Wind belts, 122; - map, 123 - -Wind roses, Callao (diagrs.), 128; - Caraveli (diagrs.), 136; - Iquique (diagrs.), 131; - La Joya (diagrs.), 135; - Machu Picchu (diagrs.), 159; - Mollendo (diagrs.), 129; - Santa Lucia (diagrs.), 167; - summer and winter of 1911-1913 (diagrs.), 130 - -Winds, 114, 116; - directions at Machu Picchu, 158-159; - geologic action, 262-267; - prevailing, 125; - Santa Lucia (with diagrs.), 166-168; - trade, 122, 124; - sea-breeze, 129-132 - -Wine, 116, 117 - -Wolf, 205 - - -Yanahuara pass, 170 - -Yanatili, 41, 42, 44; - slopes at junction with Urubamba River (ill.), opp. p. 79 - -_Yareta_ (ill.), opp. p. 6 - -Yavero, 30, 31, 36, 38, 42, 179; - temperature curve (diagr.), 178 - -Yavero (Paucartambo) River, rubber station (ill.), opp. p. 24 - -Yuca, growing (ill.), opp. p. 75 - -Yunguyo, 176 - -Yuyato, 36, 38 - - * * * * * - -FOOTNOTES: - -[1] For all locations mentioned see maps accompanying the text or -Appendix C. - -[2] The Cashibos of the Pachitea are the tribe for whom the Piros -besought Herndon to produce “some great and infectious disease†which -could be carried up the river and let loose amongst them (Herndon, -Exploration of the Valley of the Amazon, Washington. 1854, Vol. 1, p. -196). This would-be artfulness suggests itself as something of a match -against the cunning of the Cashibos whom rumor reports to imitate the -sounds of the forest animals with such skill as to betray into their -hands the hunters of other tribes (see von Tschudi, Travels in Peru -During the Years 1838-1842, translated from the German by Thomasina -Ross, New York, 1849, p. 404). - -[3] The early chronicles contain several references to Antisuyu and the -Antis. Garcilaso de la Vega’s description of the Inca conquests in -Antisuyu are well known (Royal Commentaries of the Yncas, Book 4, -Chapters 16 and 17, Hakluyt Soc. Publs., 1st Ser., No. 41, 1869 and Book -7, Chapters 13 and 14, No. 45, 1871). Salcamayhua who also chronicles -these conquests relates a legend concerning the tribute payers of the -eastern valleys. On one occasion, he says, three hundred Antis came -laden with gold from Opatari. Their arrival at Cuzco was coincident with -a killing frost that ruined all the crops of the basin whence the three -hundred fortunates were ordered with their gold to the top of the high -hill of Pachatucsa (Pachatusun) and there buried with it (An Account of -the Antiquities of Peru, Hakluyt Soc. Publs., 1st Ser., No. 48, 1873). - -[4] Notice of a Journey to the Northward and also to the Northeastward -of Cuzco. Royal Geog. Soc. Journ., Vol. 6, 1836, pp. 174-186. - -[5] Walle states (Le Pérou Economique, Paris, 1907, p. 297) that the -Conibos, a tribe of the Ucayali, make annual _correrias_ or raids during -the months of July, August, and September, that is during the season of -low water. Over seven hundred canoes are said to participate and the -captives secured are sold to rubber exploiters, who, indeed, frequently -aid in the organization of the raids. - -[6] Distances are not taken from the map but from the trail. - -[7] Compare with Raimondi’s description of Quiches on the left bank of -the Marañon at an elevation of 9,885 feet (3,013 m.): “the few small -springs scarcely suffice for the little patches of alfalfa and other -sowings have to depend on the precarious rains.... Every drop of water -is carefully guarded and from each spring a series of well-like basins -descending in staircase fashion make the most of the scant supply.†(El -Departamento de Ancachs, Lima, 1873.) - -[8] Daily Cons. and Trade Report, June 10, 1914, No. 135, and Commerce -Reports, March 20, 1916, No. 66. - -[9] Reference to the figures in this chapter will show great variation -in the level of the timber line depending upon insolation as controlled -by slope exposure and upon moisture directly as controlled largely by -exposure to winds. In some places these controls counteract each other; -in other places they promote each other’s effects. The topographic and -climatic cross-sections and regional diagrams elsewhere in this book -also emphasize the patchiness of much of the woodland and scrub, some -noteworthy examples occurring in the chapter on the Eastern Andes. Two -of the most remarkable cases are the patch of woodland at 14,500 feet -(4,420 m.) just under the hanging glacier of Soiroccocha, and the other -the quenigo scrub on the lava plateau above Chuquibamba at 13,000 feet -(3,960 m.). The strong compression of climatic zones in the Urubamba -Valley below Santa Ana brings into sharp contrast the grassy ridge -slopes facing the sun and the forested slopes that have a high -proportion of shade. Fig. 54 represents the general distribution but the -details are far more complicated. See also Figs. 53A and 53B. (See -Coropuna Quadrangle.) - -[10] Commenting on the excellence of the cacao of the montaña of the -Urubamba von Tschudi remarked (op. cit., p. 37) that the long land -transport prevented its use in Lima where the product on the market is -that imported from Guayaquil. - -[11] The inadequacy of the labor supply was a serious obstacle in the -early days as well as now. In the documents pertaining to the “Obispados -y Audiencia del Cuzco†(Vol. 11, p. 349 of the “Juicio de Limites entre -el Perú y Bolivia, Prueba Peruana presentada al Gobierno de la República -Argentina por Victor M. Maurtua,†Barcelona, 1900) we find the report -that the natives of the curacy of Ollantaytambo who came down from the -hills to Huadquiña to hear mass were detained and compelled to give a -day’s service on the valley plantations under pain of chastisement. - -[12] The Spanish occupation of the eastern valleys was early and -extensive. Immediately after the capture of the young Inca Tupac Amaru -and the final subjugation of the province of Vilcapampa colonists -started the cultivation of coca and cane. Development of the main -Urubamba Valley and tributary valleys proceeded at a good rate: so also -did their troubles. Baltasar de Ocampo writing in 1610 (Account of the -Province of Vilcapampa, Hakluyt Soc. Publs., Ser. 2, Vol. 22, 1907, pp. -203-247) relates the occurrence of a general uprising of the negroes -employed on the sugar plantations of the region. But the peace and -prosperity of every place on the eastern frontier was unstable and quite -generally the later eighteenth and earlier nineteenth centuries saw a -retreat of the border of civilization. The native rebellion of the -mid-eighteenth century in the montaña of Chanchamayo caused entire -abandonment of a previously flourishing area. When Raimondi wrote in -1885 (La Montaña de Chanchamayo, Lima, 1885) some of the ancient -hacienda sites were still occupied by savages. In the Paucartambo -valleys, settlement began by the end of the sixteenth century and at the -beginning of the nineteenth before their complete desolation by the -savages they were highly prosperous. Paucartambo town, itself, once -important for its commerce in coca is now in a sadly decadent condition. - -[13] Notice of a Journey to the Northward and also to the Eastward of -Cuzco, and among the Chunchos Indians, in July, 1835. Journ. Royal Geog. -Soc., Vol. 6, 1836, pp. 174-186. - -[14] Bol. Soc. Geog. de Lima, Vol. 8, 1898, p. 45. - -[15] Marcoy who traveled in Peru in the middle of the last century was -greatly impressed by the sympathetic changes of aspect and topography -and vegetation in the eastern valleys. He thus describes a sudden change -of scene in the Occobamba valley: “... the trees had disappeared, the -birds had taken wing, and great sandy spaces, covered with the latest -deposits of the river, alternated with stretches of yellow grass and -masses of rock half-buried in the ground.†(Travels in South America, -translated by Elihu Rich, 2 vols. New York, 1875, Vol. 1, p. 326.) - -[16] According to the latest information (August, 1916) of the Bolivia -Railway Co., trains are running from Oruro to Buen Retiro, 35 km. from -Cochabamba. Thence connection with Cochabamba is made by a tram-line -operated by the Electric Light and Power Co. of that city. The Bulletin -of the Pan-American Union for July, 1916, also reports the proposed -introduction of an automobile service for conveyance of freight and -passengers. - -[17] During his travels Raimondi collected many instances of the -isolation and conservatism of the plateau Indian: thus there is the -village of Pampacolca near Coropuna, whose inhabitants until recently -carried their idols of clay to the slopes of the great white mountain -and worshiped them there with the ritual of Inca days (El Perú, Lima, -1874, Vol. 1). - -[18] Raimondi (op. cit., p. 109) has a characteristic description of the -“Camino del Peñon†in the department of La Libertad: “... the ground -seems to disappear from one’s feet; one is standing on an elevated -balcony looking down more than 6,000 feet to the valley ... the road -which descends the steep scarp is a masterpiece.†- -[19] Figs. 67 and 68 are from Bol. de Minas del Perú, 1906, No. 37, pp. -82 and 84 respectively. - -[20] The BoletÃn de Minas del Peru, No. 34, 1905, contains a graphic -representation of the régime of the Rio Chili at Arequipa for the years -1901-1905. - -[21] Hann (Handbook of Climatology, translated by R. De C. Ward, New -York, 1903) indicates a contributory cause in the upwelling of cold -water along the coast caused by the steady westerly drift of the -equatorial current. - -[22] This is the elevation obtained by the Peruvian Expedition. -Raimondi’s figure (1,832 m.) is higher. - -[23] According to Ward’s observations the base of the cloud belt -averages between 2,000 and 3,000 feet above sea level (Climatic Notes -Made During a Voyage Around South America, Journ. of School Geogr., Vol. -2, 1898). On the south Peruvian coast, specifically at Mollendo, -Middendorf found the cloud belt beginning about 1,000 feet and extending -upwards to elevations of 3,000 to 4,000 feet. At Lima the clouds descend -to lower levels (El Clima de Lima, Bol. Soc. Geogr. de Lima, Vol. 15, -1904). In the third edition of his Süd und Mittelamerika (Leipzig and -Vienna, 1914) Sievers says that at Lima in the winter the cloud on the -coast does not exceed an elevation of 450 m. (1,500 feet) while on the -hills it lies at elevations between 300 and 700 m. (1,000 and 2,300 -feet). - -[24] In most of the coast towns the ford or ferry is an important -institution and the _chimbadores_ or _baleadores_ as they are called are -expert at their trade: they know the régime of the rivers to a nicety. -Several settlements owe their origin to the exigencies of -transportation, permanent and periodic; thus before the development of -its irrigation system Camaná, according to General Miller (Memoirs, -London, 1829, Vol. 2, p. 27), was a hamlet of some 30 people who gained -their livelihood through ferrying freight and passengers across the -Majes River. - -[25] A dry pocket in the Huallaga basin between 6° and 7° S. is -described by Spruce (Notes of a Botanist on the Amazon and Andes, 2 -vols., London, 1908). Tarapoto at an elevation of 1,500 feet above sea -level, encircled by hills rising 2,000 to 3,000 feet higher, rarely -experiences heavy rain though rain falls frequently on the hills. - -[26] Speaking of Cómas situated at the headwaters of a source of the -Perene amidst a multitude of _quebradas_ Raimondi (op. cit., p. 109) -says it “might properly be called the town of the clouds, for there is -not a day during the year, at any rate towards the evening, when the -town is not enveloped in a mist sufficient to hide everything from -view.†- -[27] Observer: E. C. Erdis of the 1912 and 1914-15 Expeditions. - -[28] Percentages given because the number of observations varies. - -[29] Observer: Señor Valdivia. For location of Santa Lucia see Fig. 66. - -[30] Observations began on May 12. - -[31] For the first half of the month only; no record for the second -half. - -[32] BoletÃn de la Sociedad Geográfica de Lima, Vol. 13, pp. 473-480, -Lima, 1903. - -[33] BoletÃn del Cuerpo de Ingenieros de Minas del Perú, No. 34, Lima, -1905, also reproduced in No. 45, 1906. - -[34] The record is copied literally without regard to the absurdity of -the second and third decimal places. - -[35] In the Eastern Cordillera, however, snowstorms may be more serious. -Prior to the construction of the Urubamba Valley Road by the Peruvian -government the three main routes to the Santa Ana portion of the valley -proceeded via the passes of Salcantay, Panticalla, and Yanahuara -respectively. Frequently all are completely snow-blocked and fatalities -are by no means unknown. In 1864 for instance nine persons succumbed on -the Yanahuara pass (Raimondi, op. cit., p. 109). - -[36] BoletÃn de la Sociedad Geográfica de Lima, Vol. 27, 1911; Vol. 28, -1912. - -[37] BoletÃn del Cuerpo de Ingenieros de Minas del Perú, No. 65, 1908. - -[38] This figure is approximate: some days’ records were missing from -the first three months of the year and the total was estimated on a -proportional basis. - -[39] Christoval de Molina, The Fables and Rites of the Yncas, Hakluyt -Soc. Publs., 1st Ser., No. 48, 1873. - -[40] See Meteorologische Zeitschrift, Vol. 5, p. 195, 1888. Also cited -by J. Hann in Handbuch der Climatologie, Vol. 2, Stuttgart, 1897; W. -Sievers, Süd und Mittelamerika, Leipzig and Vienna, 1914, p. 334. - -[41] The Physiography of the Central Andes, Am. Journ. Sci., Vol. 40, -1909, pp. 197-217 and 373-402. - -[42] Results of an Expedition to the Central Andes, Bull. Am. Geog. -Soc., Vol. 46, 1914. Figs. 28 and 29. - -[43] The Physiography of the Central Andes, by Isaiah Bowman; Am. Journ. -Sci., Vol. 28, 1909, pp. 197-217 and 373-402. See especially, _ibid._, -Fig. 11, p. 216. - -[44] Travels Amongst the Great Andes of the Equator, 1892. - -[45] GeografÃa y GeologÃa del Ecuador, 1892. - -[46] Das Hochgebirge der Republik Ecuador, Vol. 2, 2 Ost-Cordillera, -1902, p. 162. - -[47] Contributions to the Geology of British East Africa; Pt. 1, The -Glacial Geology of Mount Kenia, Quart. Journ. Geol. Soc., Vol. 50, 1894, -p. 523. - -[48] See especially A. Penck (Penck and Brückner), Die Alpen im -Eiszeitalter, 1909, Vol. 1, p. 6, and I. C. Russell, Glaciers of Mount -Rainier, 18th Ann. Rep’t, U. S. Geol. Surv., 1890-97, Sect. 2, pp. -384-385. - -[49] Die Sierra Nevada de Santa Marta und die Sierra de Perijá, -Zeitschrift der Gesellschaft für Erdkunde zu Berlin, Vol. 23, 1888, pp. -1-158. - -[50] For a list of the fossils that form the basis of the age -determinations in this chapter see Appendix B. - -[51] Eastern Bolivia and the Gran Chaco, Proc. Royal Geogr. Soc., Vol. -3, 1881, pp. 401-420. - -[52] The Physiography of the Central Andes, Am. Journ. Sci., Vol. 28, -1909, p. 395. - -[53] See paper by H. S. Palmer, my assistant on the Expedition to the -Central Andes, 1913, entitled: Geological Notes on the Andes of -Northwestern Argentina, Am. Journ. Sci., Vol. 38, 1914, pp. 309-330. - -[54] The best photograph of this condition which I have yet seen is in -W. Sievers, Südund Mittelamerika, second ed., 1914, Plate 15, p. 358. - -[55] Paschinger, Die Schneegrenze in verschiedenen Klimaten. Peter. -Mitt. Erganz’heft, Nr. 173. 1912, pp. 92-93. - -[56] Hann, Handbook of Climatology, Part 1, trans. by Ward, 1903, p. -232. - -[57] S. I. Bailey, Peruvian Meteorology, 1888-1890. Ann. Astron. Observ. -of Harvard Coll., Vol. 39, Pt. I, 1899, pp. 1-3. - -[58] F. E. Matthes, Glacial Sculpture of the Bighorn Mountains, Wyoming, -Twentieth Ann. Rept. U. S. Geol. Surv., 1899-1900, Pt. 2, p. 181. - -[59] Idem, p. 190. - -[60] W. H. Hobbs, Characteristics of Existing Glaciers, 1911, p. 22. - -[61] Op. cit., p. 286. Reference on p. 190. - -[62] Corrosion of Gravity Streams with Application of the Ice Flood -Hypothesis, Journ. and Proc. of the Royal Society of N. S. Wales, Vol. -43, 1909, p. 286. - -[63] G. K. Gilbert, Systematic Asymmetry of Crest Lines in the High -Sierra of California. Jour. Geol., Vol. 12, 1904, p. 582. - -[64] Op. cit., p. 300; reference on p. 582. - -[65] Op. cit., p. 300; see pp. 579-588 and Fig. 8. - -[66] The observation at Camaná checks very closely with a Peruvian -observation the value of which is S. 16° 37′ 00″. - - - - - - -End of Project Gutenberg's The Andes of Southern Peru, by Isaiah Bowman - -*** END OF THIS PROJECT GUTENBERG EBOOK THE ANDES OF SOUTHERN PERU *** - -***** This file should be named 42860-0.txt or 42860-0.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/4/2/8/6/42860/ - -Produced by Chuck Greif, The University of Florida Digital -Collections and the Online Distributed Proofreading Team -at http://www.pgdp.net - - -Updated editions will replace the previous one--the old editions -will be renamed. - -Creating the works from public domain print editions means that no -one owns a United States copyright in these works, so the Foundation -(and you!) can copy and distribute it in the United States without -permission and without paying copyright royalties. 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You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org/license - - -Title: The Andes of Southern Peru - Geographical Reconnaissance along the Seventy-Third Meridian - -Author: Isaiah Bowman - -Release Date: June 2, 2013 [EBook #42860] - -Language: English - -Character set encoding: ISO-8859-1 - -*** START OF THIS PROJECT GUTENBERG EBOOK THE ANDES OF SOUTHERN PERU *** - - - - -Produced by Chuck Greif, The University of Florida Digital -Collections and the Online Distributed Proofreading Team -at http://www.pgdp.net - - - - - -Transcriber's note: The etext attempts to replicate the printed book as -closely as possible. Obvious errors in spelling and punctuation have -been corrected. The spellings of names, places and Spanish words used by -the author have not been corrected or modernized by the etext -transcriber. The footnotes have been moved to the end of the text body. -The images have been moved from the middle of a paragraph to the closest -paragraph break for ease of reading. - - [Illustration] - - - - - THE ANDES OF SOUTHERN - PERU - - GEOGRAPHICAL RECONNAISSANCE ALONG THE - SEVENTY-THIRD MERIDIAN - - BY - - ISAIAH BOWMAN - Director of the American Geographical Society - - [Illustration: colophon] - - PUBLISHED FOR - THE AMERICAN GEOGRAPHICAL SOCIETY - OF NEW YORK - - BY - - HENRY HOLT AND COMPANY - - 1916 - - LATIN - AMERICA - - COPYRIGHT, 1918 - - BY - - HENRY HOLT AND COMPANY - - THE QUINN & BODEN CO. PRESS - RAHWAY, N.J. - - TO - - C. G. B. - - - - -PREFACE - - -The geographic work of the Yale Peruvian Expedition of 1911 was -essentially a reconnaissance of the Peruvian Andes along the 73rd -meridian. The route led from the tropical plains of the lower Urubamba -southward over lofty snow-covered passes to the desert coast at Camaná. -The strong climatic and topographic contrasts and the varied human life -which the region contains are of geographic interest chiefly because -they present so many and such clear cases of environmental control -within short distances. Though we speak of "isolated" mountain -communities in the Andes, it is only in a relative sense. The extreme -isolation felt in some of the world's great deserts is here unknown. It -is therefore all the more remarkable when we come upon differences of -customs and character in Peru to find them strongly developed in spite -of the small distances that separate unlike groups of people. - -My division of the Expedition undertook to make a contour map of the -two-hundred-mile stretch of mountain country between Abancay and the -Pacific coast, and a great deal of detailed geographic and physiographic -work had to be sacrificed to insure the completion of the survey. Camp -sites, forage, water, and, above all, strong beasts for the -topographer's difficult and excessively lofty stations brought daily -problems that were always serious and sometimes critical. I was so -deeply interested in the progress of the topographic map that whenever -it came to a choice of plans the map and not the geography was first -considered. The effect upon my work was to distribute it with little -regard to the demands of the problems, but I cannot regret this in view -of the great value of the maps. Mr. Kai Hendriksen did splendid work in -putting through two hundred miles of plane-tabling in two months under -conditions of extreme difficulty. Many of his triangulation stations -ranged in elevation from 14,000 to nearly 18,000 feet, and the cold and -storms--especially the hailstorms of mid-afternoon--were at times most -severe. - -It is also a pleasure to say that Mr. Paul Baxter Lanius, my assistant -on the lower Urubamba journey, rendered an invaluable service in -securing continuous weather records at Yavero and elsewhere, and in -getting food and men to the river party at a critical time. Dr. W. G. -Erving, surgeon of the Expedition, accompanied me on a canoe journey -through the lower gorge of the Urubamba between Rosalina and the mouth -of the Timpia, and again by pack train from Santa Ana to Cotahuasi. For -a time he assisted the topographer. It is due to his prompt surgical -assistance to various members of the party that the field work was -uninterrupted. He was especially useful when two of our river Indians -from Pongo de Mainique were accidentally shot. I have since been -informed by their _patrón_ that they were at work within a few months. - -It is difficult to express the gratitude I feel toward Professor Hiram -Bingham, Director of the Expedition, first for the executive care he -displayed in the organization of the expedition's plans, which left the -various members largely care-free, and second, for generously supplying -the time of various assistants in the preparation of results. I have -enjoyed so many facilities for the completion of the work that at least -a year's time has been saved thereby. Professor Bingham's enthusiasm for -pioneer field work was in the highest degree stimulating to every member -of the party. Furthermore, it led to a determination to complete at all -hazards the original plans. - -Finally, I wish gratefully to acknowledge the expert assistance of Miss -Gladys M. Wrigley, of the editorial staff of the American Geographical -Society, who prepared the climatic tables, many of the miscellaneous -data related thereto, and all of the curves in Chapter X. Miss Wrigley -also assisted in the revision of Chapters IX and X and in the correction -of the proof. Her eager and in the highest degree faithful assistance in -these tasks bespeaks a true scientific spirit. - -ISAIAH BOWMAN. - - -SPECIAL ACKNOWLEDGMENTS FOR ILLUSTRATIONS - -Fig. 28. Photograph by H. L. Tucker, Engineer, Yale Peruvian Expedition -of 1911. - -Fig. 43. Photograph by H. L. Tucker. - -Fig. 44. Photograph by Professor Hiram Bingham. - -Figs. 136, 139, 140. Data for hachured sketch maps, chiefly from -topographic sheets by A. H. Bumstead, Topographer to Professor Bingham's -Peruvian Expeditions of 1912 and 1914. - - - - -CONTENTS - - -PART I - -HUMAN GEOGRAPHY - -CHAPTER PAGE - -I. THE REGIONS OF PERU 1 - -II. THE RAPIDS AND CANYONS OF THE URUBAMBA 8 - -III. THE RUBBER FORESTS 22 - -IV. THE FOREST INDIANS 36 - -V. THE COUNTRY OF THE SHEPHERDS 46 - -VI. THE BORDER VALLEYS OF THE EASTERN ANDES 68 - -VII. THE GEOGRAPHIC BASIS OF REVOLUTIONS AND OF HUMAN -CHARACTER IN THE PERUVIAN ANDES 88 - -VIII. THE COASTAL DESERT 110 - -IX. CLIMATOLOGY OF THE PERUVIAN ANDES 121 - -X. METEOROLOGICAL RECORDS FROM THE PERUVIAN ANDES 157 - - -PART II - -PHYSIOGRAPHY OF THE PERUVIAN ANDES - -XI. THE PERUVIAN LANDSCAPE 183 - -XII. THE WESTERN ANDES: THE MARITIME CORDILLERA OR CORDILLERA -OCCIDENTAL 199 - -XIII. THE EASTERN ANDES: THE CORDILLERA VILCAPAMPA 204 - -XIV. THE COASTAL TERRACES 225 - -XV. PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 233 - -XVI. GLACIAL FEATURES 274 - - -APPENDIX A. SURVEY METHODS EMPLOYED IN THE CONSTRUCTION OF -THE SEVEN ACCOMPANYING TOPOGRAPHIC SHEETS 315 - -APPENDIX B. FOSSIL DETERMINATIONS 321 - -APPENDIX C. KEY TO PLACE NAMES 324 - -INDEX 327 - - -TOPOGRAPHIC SHEETS - -Camaná Quadrangle 114 - -Aplao " 120 - -Coropuna " 188 - -Cotahuasi " 192 - -La Cumbre " 202 - -Antabamba " 282 - -Lambrama " - - - - -PART I - -HUMAN GEOGRAPHY - - - - -CHAPTER I - -THE REGIONS OF PERU - - -Let four Peruvians begin this book by telling what manner of country -they live in. Their ideas are provincial and they have a fondness for -exaggerated description: but, for all that, they will reveal much that -is true because they will at least reveal themselves. Their opinions -reflect both the spirit of the toiler on the land and the outlook of the -merchant in the town in relation to geography and national problems. -Their names do not matter; let them stand for the four human regions of -Peru, for they are in many respects typical men. - - -THE FOREST DWELLER - -One of them I met at a rubber station on the lower Urubamba River.[1] He -helped secure my canoe, escorted me hospitably to his hut, set food and -drink before me, and talked of the tropical forest, the rubber business, -the Indians, the rivers, and the trails. In his opinion Peru was a land -of great forest resources. Moreover, the fertile plains along the river -margins might become the sites of rich plantations. The rivers had many -fish and his garden needed only a little cultivation to produce an -abundance of food. Fruit trees grew on every hand. He had recently -married the daughter of an Indian chief. - -Formerly he had been a missionary at a rubber station on the Madre de -Dios, where the life was hard and narrow, and he doubted if there were -any real converts. Himself the son of an Englishman and a Chilean woman, -he found, so he said, that a missionary's life in the rubber forest was -intolerable for more than a few years. Yet he had no fault to find with -the religious system of which he had once formed a part; in fact he had -still a certain curious mixed loyalty to it. Before I left he gave me a -photograph of himself and said with little pride and more sadness that -perhaps I would remember him as a man that had done some good in the -world along with much that might have been better. - -We shall understand our interpreter better if we know who his associates -were. He lived with a Frenchman who had spent several years in Africa as -a soldier in the "Foreign Legion." If you do not know what that means, -you have yet all the pleasure of an interesting discovery. The Frenchman -had reached the station the year before quite destitute and clad only in -a shirt and a pair of trousers. A day's journey north lived a young -half-breed--son of a drunken father and a Machiganga woman, who cheated -me so badly when I engaged Indian paddlers that I should almost have -preferred that he had robbed me. Yet in a sense he had my life in his -hands and I submitted. A German and a native Peruvian ran a rubber -station on a tributary two days' journey from the first. It will be -observed that the company was mixed. They were all Peruvians, but of a -sort not found in such relative abundance elsewhere. The defeated and -the outcast, as well as the pioneer, go down eventually to the hot -forested lands where men are forgotten. - -While he saw gold in every square mile of his forested region, my -clerical friend saw misery also. The brutal treatment of the Indians by -the whites of the Madre de Dios country he could speak of only as a man -reviving a painful memory. The Indians at the station loved him -devotedly. There was only justice and kindness in all his dealings. -Because he had large interests to look after, he knew all the members of -the tribe, and his word was law in no hackneyed sense. A kindlier man -never lived in the rubber forest. His influence as a high-souled man of -business was vastly greater than as a missionary in this frontier -society. He could daily illustrate by practical example what he had -formerly been able only to preach. - -[Illustration: Fig. 1--Tropical vegetation, clearing on the river bank -and rubber station at Pongo de Mainique. The pronounced scarp on the -northeastern border of the Andes is seen in the right background.] - -[Illustration: Fig. 2--Pushing a heavy dugout against the current in the -rapids below Pongo de Mainique. The indian boy and his father in the -canoe had been accidentally shot.] - -[Illustration: Fig. 3--From the sugar cane, Urubanba Valley, at Colpani. -On the northeastern border of the Cordillera Vilcapampa looking -upstream. In the extreme background and thirteen sixteens of an inch -from the top of the picture is the sharp peak of Salcantay. Only the -lower end of the more open portion of the Canyon of Torontoy is here -shown. There is a field of sugar cane in the foreground and the valley -trail is shown on the opposite side of the river.] - -He thought the life of the Peruvian cities debasing. The coastal -valleys were small and dry and the men who lived there were crowded and -poor (sic). The plateau was inhabited by Indians little better than -brutes. Surely I could not think that the fine forest Indian was lower -than the so-called civilized Indian of the plateau. There was plenty of -room in the forest; and there was wealth if you knew how to get at it. -Above all you were far from the annoying officials of the government, -and therefore could do much as you pleased so long as you paid your -duties on rubber and did not wantonly kill too many Indians. - -For all his kindly tolerance of men and conditions he yet found fault -with the government. "They" neglected to build roads, to encourage -colonization, and to lower taxes on the forest products, which were -always won at great risk. Nature had done her part well--it was only -government that hindered. Moreover, the forested region was the land of -the future. If Peru was to be a great nation her people would have to -live largely upon the eastern plains. Though others spoke of "going in" -and "coming out" of the rubber country as one might speak of entering -and leaving a dungeon, he always spoke of it as home. Though he now -lived in the wilderness he hoped to see the day when plantations covered -the plains. A greater Peru and the forest were inseparable ideas to him. - - -THE EASTERN VALLEY PLANTER - -My second friend lived in one of the beautiful mountain valleys of the -eastern Andes. We walked through his clean cacao orchards and cane -fields. Like the man in the forest, he believed in the thorough -inefficiency of the government; otherwise why were there no railways for -the cheaper transportation of the valley products, no dams for the -generation of power and the storage of irrigation water, not even roads -for mule carts? Had the government been stable and efficient there would -now be a dense population in the eastern valleys. Revolutions were the -curse of these remote sections of the country. The ne'er-do-wells became -generals. The loafer you dismissed today might demand ten thousand -dollars tomorrow or threaten to destroy your plantation. The government -troops might come to help you, but they were always too late. - -For this one paid most burdensome taxes. Lima profited thereby, not the -valley planters. The coast people were the favored of Peru anyhow. They -had railroads, good steamer service, public improvements at government -expense, and comparatively light taxes. If the government were impartial -the eastern valleys also would have railways and a dense population. Who -could tell? Perhaps the capital city might be here. Certainly it was -better to have Lima here than on the coast where the Chileans might at -any time take it again. The blessings of the valleys were both rich and -manifold. Here was neither a cold plateau nor the hot plains, but -fertile valleys with a vernal climate. - -We talked of much else, but our conversation had always the pioneer -flavor. And though an old man he saw always the future Peru growing -wonderfully rich and powerful as men came to recognize and use the -resources of the eastern valleys. This too was the optimism of the -pioneer. Once started on that subject he grew eloquent. He was -provincial but he was also intensely patriotic. He never missed an -opportunity to impress upon his guests that a great state would arise -when people and rulers at last recognized the wealth of eastern Peru. - - -THE HIGHLAND SHEPHERD - -The people who live in the lofty highlands and mountains of Peru have -several months of real winter weather despite their tropical latitude. -In the midst of a snowstorm in the Maritime Cordillera I met a solitary -traveler bound for Cotahuasi on the floor of a deep canyon a day's -journey toward the east. It was noon and we halted our pack trains in -the lee of a huge rock shelter to escape the bitter wind that blew down -from the snow-clad peaks of Solimana. Men who follow the same trails are -fraternal. In a moment we had food from our saddle-bags spread on the -snow under the corner of a _poncho_ and had exchanged the best in each -other's collection as naturally as friends exchange greetings. By the -time I had told him whence and why in response to his inevitable -questions we had finished the food and had gathered a heap of _tola_ -bushes for a fire. The _arriero_ (muleteer) brought water from a spring -in the hollow below us. Though the snow thickened, the wind fell. We -were comfortable, even at 16,000 feet, and called the place "The -Salamanca Club." Then I questioned him, and this is what he said: - -"I live in the deep valley of Cotahuasi, but my lands lie chiefly up -here on the plateau. My family has held title to this _puna_ ever since -the Wars of Liberation, except for a few years after one of our early -revolutions. I travel about a great deal looking after my flocks. Only -Indians live up here. Away off yonder beyond that dark gorge is a group -of their huts, and on the bright days of summer you may see their sheep, -llamas, and alpacas up here, for on the floors of the watered valleys -that girdle these volcanoes there are more tender grasses than grow on -this _despoblado_. I give them corn and barley from my irrigated fields -in the valley; they give me wool and meat. The alpaca wool is most -valuable. It is hard to get, for the alpaca requires short grasses and -plenty of water, and you see there is only coarse tufted ichu grass -about us, and there are no streams. It is all right for llamas, but -alpacas require better forage. - -"No one can imagine the poverty and ignorance of these mountain -shepherds. They are filthier than beasts. I have to watch them -constantly or they would sell parts of the flocks, which do not belong -to them, or try to exchange the valuable alpaca wool for coca leaves in -distant towns. They are frequently drunk." - -"But where do they get the drink?" I asked. "And what do you pay them?" - -"Oh, the drink is chiefly imported alcohol, and also _chicha_ made from -corn. They insist on having it, and do better when I bring them a little -now and then. They get much more from the dealers in the towns. As for -pay, I do not pay them anything in money except when they bring meat to -the valley. Then I give them a few _reales_ apiece for the sheep and a -little more for the llamas. The flocks all belong to me really, but of -course the poor Indian must have a little money. Besides, I let him have -a part of the yearly increase. It is not much, but he has always lived -this way and I suppose that he is contented after a fashion." - -Then he became eager to tell what wealth the mountains contained in soil -and climate if only the right grasses were introduced by the government. - -"Here, before us, are vast _punas_ almost without habitations. If the -officials would bring in hardy Siberian grasses these lava-covered -plateaus might be carpeted with pasture. There would be villages here -and there. The native Indians easily stand the altitude. This whole -Cordillera might have ten times as many people. Why does the government -bother about concessions in the rubber forests and roads to the eastern -valleys when there are these vast tracts only requiring new seeds to -develop into rich pastures? The government could thus greatly increase -its revenues because there is a heavy tax on exported wool." - -Thus he talked about the bleak Cordillera until we forgot the pounding -of our hearts and our frequent gasps for breath on account of the -altitude. His rosy picture of a well-populated highland seemed to bring -us down nearer sea level where normal folks lived. To the Indians the -altitude is nothing. It has an effect, but it is slight; at any rate -they manage to reproduce their kind at elevations that would kill a -white mother. If alcohol were abolished and better grasses introduced, -these lofty pastures might indeed support a much larger population. The -sheep pastures of the world are rapidly disappearing before the march of -the farmer. Here, well above the limit of cultivation, is a permanent -range, one of the great as well as permanent assets of Peru. - - -THE COASTAL PLANTER - -The man from the deep Majes Valley in the coastal desert rode out with -me through cotton fields as rich and clean as those of a Texas -plantation. He was tall, straight-limbed, and clear-eyed--one of the -energetic younger generation, yet with the blood of a proud old family. -We forded the river and rode on through vineyards and fig orchards -loaded with fruit. His manner became deeply earnest as he pictured the -future of Peru, when her people would take advantage of scientific -methods and use labor-saving machinery. He said that the methods now in -use were medieval, and he pointed to a score of concrete illustrations. -Also, here was water running to waste, yet the desert was on either -hand. There should be dams and canals. Every drop of water was needed. -The population of the valley could be easily doubled. - -[Illustration: FIG. 4--Large ground moss--so-called _yareta_--used for -fuel. It occurs in the zone of Alpine vegetation and is best developed -in regions where the snowline is highest. The photograph represents a -typical occurrence between Cotahuasi and Salamanca, elevation 16,000 -feet (4,880 m.). The snowline is here at 17,500 feet (5,333 m.). In the -foreground is the most widely distributed _tola_ bush, also used for -fuel.] - -[Illustration: FIG. 5.--Expedition's camp near Lamgrama, 15,500 feet -(4,720 m.), after a snowstorm The location is midway in the pasture -zone.] - -[Illustration: FIG. 6--Irrigated Chili Valley on the outskirts of -Arequipa. The lower slopes of El Misti are in the left background. The -_Alto de los Huesos_ or Plateau of Bones lies on the farther side of the -valley.] - -[Illustration: FIG. 7--Crossing the highest pass (Chuquito) in the -Cordillera Vilcapampa, 14,500 feet (4,420 m.). Grazing is here carried -on up to the snowline.] - -Capital was lacking but there was also lacking energy among the people. -Slipshod methods brought them a bare living and they were too easily -contented. Their standards of life should be elevated. Education was -still for the few, and it should be universal. A new spirit of progress -was slowly developing--a more general interest in public affairs, a -desire to advance with the more progressive nations of South -America,--and when it had reached its culmination there would be no -happier land than coastal Peru, already the seat of the densest -populations and the most highly cultivated fields. - - * * * * * - -These four men have portrayed the four great regions of Peru--the -lowland plains, the eastern mountain valleys, the lofty plateaus, and -the valley oases of the coast. This is not all of Peru. The mountain -basins have their own peculiar qualities and the valley heads of the -coastal zone are unlike the lower valleys and the plateau on either -hand. Yet the chief characteristics of the country are set forth with -reasonable fidelity in these individual accounts. Moreover the spirit of -the Peruvians is better shown thereby than their material resources. If -this is not Peru, it is what the Peruvians think is Peru, and to a high -degree a man's country is what he thinks it is--at least it is little -more to him. - - - - -CHAPTER II - -THE RAPIDS AND CANYONS OF THE URUBAMBA - - -Among the scientifically unexplored regions of Peru there is no other so -alluring to the geographer as the vast forested realm on the eastern -border of the Andes. Thus it happened that within two weeks of our -arrival at Cuzco we followed the northern trail to the great canyon of -the Urubamba (Fig. 8), the gateway to the eastern valleys and the -lowland plains of the Amazon. It is here that the adventurous river, -reënforced by hundreds of mountain-born tributaries, finally cuts its -defiant way through the last of its great topographic barriers. More -than seventy rapids interrupt its course; one of them, at the mouth of -the Sirialo, is at least a half-mile in length, and long before one -reaches its head he hears its roaring from beyond the forest-clad -mountain spurs. - -The great bend of the Urubamba in which the line of rapids occurs is one -of the most curious hydrographic features in Peru. The river suddenly -changes its general northward course and striking south of west flows -nearly fifty miles toward the axis of the mountains, where, turning -almost in a complete circle, it makes a final assault upon the eastern -mountain ranges. Fifty miles farther on it breaks through the long -sharp-crested chain of the Front Range of the Andes in a splendid gorge -more than a half-mile deep, the famous _Pongo de Mainique_ (Fig. 9). - -Our chief object in descending the line of rapids was to study the -canyon of the Urubamba below Rosalina and to make a topographic sketch -map of it. We also wished to know what secrets might be gathered in this -hitherto unexplored stretch of country, what people dwelt along its -banks, and if the vague tales of deserted towns and fugitive tribes had -any basis in fact. - -[Illustration: FIG. 8--Sketch map showing the route of the Yale-Peruvian -Expedition of 1911 down the Urubamba Valley, together with the area of -the main map and the changes in the delineation of the bend of the -Urubamba resulting from the surveys of the Expedition. Based on the -"Mapa que comprende las ultimas exploraciones y estudios verificados -desde 1900 hasta 1906," 1:1,000,000, Bol. Soc. Geogr. Lima, Vol. 25, No. -3, 1909. For details of the trail from Rosalina to Pongo de Mainique see -"Plano de las Secciones y Afluentes del Rio Urubamba: 1902-1904," scale -1:150,000 by Luis M. Robledo in Bol. Soc. Geogr. Lima, Vol. 25, No. 4, -1909. Only the lower slopes of the long mountain spurs can be seen from -the river; hence only in a few places could observations be made on the -topography of distant ranges. Paced distances of a half mile at -irregular intervals were used for the estimation of longer distances. -Directions were taken by compass corrected for magnetic deviation as -determined on the seventy-third meridian (See Appendix A). The position -of Rosalina on Robledo's map was taken as a base.] - -We could gather almost no information as to the nature of the river -except from the report of Major Kerbey, an American, who, in 1897, -descended the last twenty miles of the one hundred we proposed to -navigate. He pronounced the journey more hazardous than Major Powell's -famous descent of the Grand Canyon in 1867--an obvious exaggeration. He -lost his canoe in a treacherous rapid, was deserted by his Indian -guides, and only after a painful march through an all but impassable -jungle was he finally able to escape on an abandoned raft. Less than a -dozen have ventured down since Major Kerbey's day. A Peruvian mining -engineer descended the river a few years ago, and four Italian traders a -year later floated down in rafts and canoes, losing almost all of their -cargo. For nearly two months they were marooned upon a sand-bar waiting -for the river to subside. At last they succeeded in reaching -Mulanquiato, an Indian settlement and plantation owned by Pereira, near -the entrance to the last canyon. Their attempted passage of the worst -stretch of rapids resulted in the loss of all their rubber cargo, the -work of a year. Among the half dozen others who have made the -journey--Indians and slave traders from down-river rubber posts--there -is no record of a single descent without the loss of at least one canoe. - -To reach the head of canoe navigation we made a two weeks' muleback -journey north of Cuzco through the steep-walled granite Canyon of -Torontoy, and to the sugar and cacao plantations of the middle Urubamba, -or Santa Ana Valley, where we outfitted. At Echarati, thirty miles -farther on, where the heat becomes more intense and the first patches of -real tropical forest begin, we were obliged to exchange our beasts for -ten fresh animals accustomed to forest work and its privations. Three -days later we pitched our tent on the river bank at Rosalina, the last -outpost of the valley settlements. As we dropped down the steep mountain -slope before striking the river flood plain, we passed two half-naked -Machiganga Indians perched on the limbs of a tree beside the trail, our -first sight of members of a tribe whose territory we had now entered. -Later in the day they crossed the river in a dugout, landed on the -sand-bar above us, and gathered brush for the nightly fire, around which -they lie wrapped in a single shirt woven from the fiber of the wild -cotton. - -[Illustration: FIG. 9--The upper entrance to the Pongo de Mainique, -where the Urubamba crosses the Front Range of the Andes in a splendid -gateway 4,000 feet deep. The river is broken by an almost continuous -line of rapids.] - -[Illustration: FIG. 10--The lower half of a two-thousand-foot cliff, -granite Canyon of Torontoy, Urubamba Valley. The wall is developed -almost entirely along joint planes. It is here that the Urubamba River -crosses the granite axis of the Cordillera Vilcapampa, the easternmost -system of the Andes of southern Peru. Compare also Figs. 144 and 145.] - -[Illustration: FIG. 11--A temporary shelter-hut on a sand-bar near the -great bend of the Urubamba (see map, Fig. 8). The Machiganga Indians use -these cane shelters during the fishing season, when the river is low.] - -[Illustration: FIG. 12--Thirty-foot canoe in a rapid above Pongo de -Mainique.] - -Rosalina is hardly more than a name on the map and a camp site on the -river bank. Some distance back from the left bank of the river is a -sugar plantation, whose owner lives in the cooler mountains, a day's -journey away; on the right bank is a small clearing planted to sugar -cane and yuca, and on the edge of it is a reed hut sheltering three -inhabitants, the total population of Rosalina. The owner asked our -destination, and to our reply that we should start in a few days for -Pongo de Mainique he offered two serious objections. No one thought of -arranging so difficult a journey in less than a month, for canoe and -Indians were difficult to find, and the river trip was dangerous. -Clearly, to start without the loss of precious time would require -unusual exertion. We immediately despatched an Indian messenger to the -owner of the small hacienda across the river while one of our peons -carried a second note to a priest of great influence among the forest -Indians, Padre Mendoza, then at his other home in the distant mountains. - -The answer of Señor Morales was his appearance in person to offer the -hospitality of his home and to assist us in securing canoe and oarsmen. -To our note the Padre, from his hill-top, sent a polite answer and the -offer of his large canoe if we would but guarantee its return. His -temporary illness prevented a visit to which we had looked forward with -great interest. - -The morning after our arrival I started out on foot in company with our -_arriero_ in search of the Machigangas, who fish and hunt along the -river bank during the dry season and retire to their hill camps when the -heavy rains begin. We soon left the well-beaten trail and, following a -faint woodland path, came to the river bank about a half day's journey -below Rosalina. There we found a canoe hidden in an overhanging arch of -vines, and crossing the river met an Indian family who gave us further -directions. Their vague signs were but dimly understood and we soon -found ourselves in the midst of a _carrizo_ (reed) swamp filled with -tall bamboo and cane and crossed by a network of interlacing streams. We -followed a faint path only to find ourselves climbing the adjacent -mountain slopes away from our destination. Once again in the swamp we -had literally to cut our way through the thick cane, wade the numberless -brooks, and follow wild animal trails until, late in the day, famished -and thirsty, we came upon a little clearing on a sand-bar, the hut of La -Sama, who knew the Machigangas and their villages. - -After our long day's work we had fish and yuca, and water to which had -been added a little raw cane sugar. Late at night La Sama returned from -a trip to the Indian villages down river. He brought with him a -half-dozen Machiganga Indians, boys and men, and around the camp fire -that night gave us a dramatic account of his former trip down river. At -one point he leaped to his feet, and with an imaginary pole shifted the -canoe in a swift rapid, turned it aside from imminent wreck, and -shouting at the top of his voice over the roar of the water finally -succeeded in evading what he had made seem certain death in a whirlpool. -We kept a fire going all night long for we slept upon the ground without -a covering, and, strange as it may appear, the cold seemed intense, -though the minimum thermometer registered 59° F. The next morning the -whole party of ten sunned themselves for nearly an hour until the flies -and heat once more drove them to shelter. - -Returning to camp next day by a different route was an experience of -great interest, because of the light it threw on hidden trails known -only to the Indian and his friends. Slave raiders in former years -devastated the native villages and forced the Indian to conceal his -special trails of refuge. At one point we traversed a cliff seventy-five -feet above the river, walking on a narrow ledge no wider than a man's -foot. At another point the dim trail apparently disappeared, but when we -had climbed hand over hand up the face of the cliff, by hanging vines -and tree roots, we came upon it again. Crossing the river in the canoe -we had used the day before, we shortened the return by wading the swift -Chirumbia waist-deep, and by crawling along a cliff face for nearly an -eighth of a mile. At the steepest point the river had so under-cut the -face that there was no trail at all, and we swung fully fifteen feet -from one ledge to another, on a hanging vine high above the river. - -After two days' delay we left Rosalina late in the afternoon of August -7. My party included several Machiganga Indians, La Sama, and Dr. W. G. -Erving, surgeon of the expedition. Mr. P. B. Lanius, Moscoso (the -_arriero_), and two peons were to take the pack train as far as possible -toward the rubber station at Pongo de Mainique where preparations were -to be made for our arrival. At the first rapid we learned the method of -our Indian boatmen. It was to run the heavy boat head on into shallow -water at one side of a rapid and in this way "brake" it down stream. -Heavily loaded with six men, 200 pounds of baggage, a dog, and supplies -of yuca and sugar cane our twenty-five foot dugout canoe was as rigid as -a steamer, and we dropped safely down rapid after rapid until long after -dark, and by the light of a glorious tropical moon we beached our craft -in front of La Sama's hut at the edge of the cane swamp. - -Here for five days we endured a most exasperating delay. La Sama had -promised Indian boatmen and now said none had yet been secured. Each day -Indians were about to arrive, but by nightfall the promise was broken -only to be repeated the following morning. To save our food supply--we -had taken but six days' provisions--we ate yuca soup and fish and some -parched corn, adding to this only a little from our limited stores. At -last we could wait no longer, even if the map had to be sacrificed to -the work of navigating the canoe. Our determination to leave stirred La -Sama to final action. He secured an assistant named Wilson and embarked -with us, planning to get Indians farther down river or make the journey -himself. - -On August 12, at 4.30 P.M., we entered upon the second stage of the -journey. As we shot down the first long rapid and rounded a wooded bend -the view down river opened up and gave us our first clear notion of the -region we had set out to explore. From mountain summits in the clouds -long trailing spurs descend to the river bank. In general the slopes are -smooth-contoured and forest-clad from summit to base; only in a few -places do high cliffs diversify the scenery. The river vista everywhere -includes a rapid and small patches of _playa_ or flood plain on the -inside of the river curves. Although a true canyon hems in the river at -two celebrated passes farther down, the upper part of the river flows -in a somewhat open valley of moderate relief, with here and there a -sentinel-like peak next the river. - -A light shower fell at sunset, a typical late-afternoon downpour so -characteristic of the tropics. We landed at a small encampment of -Machigangas, built a fire against the scarred trunk of a big palm, and -made up our beds in the open, covering them with our rubber ponchos. Our -Indian neighbors gave us yuca and corn, but their neighborliness went no -further, for when our boatmen attempted to sleep under their roofs they -drove them out and fastened as securely as possible the shaky door of -their hut. - -All our efforts to obtain Indians, both here and elsewhere, proved -fruitless. One excuse after another was overcome; they plainly coveted -the trinkets, knives, machetes, muskets, and ammunition that we offered -them; and they appeared to be friendly enough. Only after repeated -assurances of our friendship could we learn the real reason for their -refusal. Some of them were escaped rubber pickers that had been captured -by white raiders several years before, and for them a return to the -rubber country meant enslavement, heavy floggings, and separation from -their numerous wives. The hardships they had endured, their final -escape, the cruelty of the rubber men, and the difficult passage of the -rapids below were a set of circumstances that nothing in our list of -gifts could overcome. My first request a week before had so sharpened -their memory that one of them related the story of his wrongs, a recital -intensely dramatic to the whole circle of his listeners, including -myself. Though I did not understand the details of his story, his tones -and gesticulations were so effective that they held me as well as his -kinsmen of the woods spellbound for over an hour. - -It is appalling to what extent this great region has been depopulated by -the slave raiders and those arch enemies of the savage, smallpox and -malaria. At Rosalina, over sixty Indians died of malaria in one year; -and only twenty years ago seventy of them, the entire population of the -Pongo, were swept away by smallpox. For a week we passed former camps -near small abandoned clearings, once the home of little groups of -Machigangas. Even the summer shelter huts on the sand-bars, where the -Indians formerly gathered from their hill homes to fish, are now almost -entirely abandoned. Though our men carefully reconnoitered each one for -fear of ambush, the precaution was needless. Below the Coribeni the -Urubamba is a great silent valley. It is fitted by Nature to support -numerous villages, but its vast solitudes are unbroken except at night, -when a few families that live in the hills slip down to the river to -gather yuca and cane. - -By noon of the second day's journey we reached the head of the great -rapid at the mouth of the Sirialo. We had already run the long Coribeni -rapid, visited the Indian huts at the junction of the big Coribeni -tributary, exchanged our canoe for a larger and steadier one, and were -now to run one of the ugliest rapids of the upper river. The rapid is -formed by the gravel masses that the Sirialo brings down from the -distant Cordillera Vilcapampa. They trail along for at least a -half-mile, split the river into two main currents and nearly choke the -mouth of the tributary. For almost a mile above this great barrier the -main river is ponded and almost as quiet as a lake. - -We let our craft down this rapid by ropes, and in the last difficult -passage were so roughly handled by our almost unmanageable canoe as to -suffer from several bad accidents. All of the party were injured in one -way or another, while I suffered a fracture sprain of the left foot that -made painful work of the rest of the river trip. - -At two points below Rosalina the Urubamba is shut in by steep mountain -slopes and vertical cliffs. Canoe navigation below the Sirialo and -Coribeni rapids is no more hazardous than on the rapids of our northern -rivers, except at the two "pongos" or narrow passages. The first occurs -at the sharpest point of the abrupt curve shown on the map; the second -is the celebrated Pongo de Mainique. In these narrow passages in time of -high water there is no landing for long stretches. The bow paddler -stands well forward and tries for depth and current; the stern paddler -keeps the canoe steady in its course. When paddlers are in agreement -even a heavy canoe can be directed into the most favorable channels. -Our canoemen were always in disagreement, however, and as often as not -we shot down rapids at a speed of twenty miles an hour, broadside on, -with an occasional bump on projecting rocks or boulders whose warning -ordinary boatmen would not let go unheeded. - -The scenery at the great bend is unusually beautiful. The tropical -forest crowds the river bank, great cliffs rise sheer from the water's -edge, their faces overhung with a trailing drapery of vines, and in the -longer river vistas one may sometimes see the distant heights of the -Cordillera Vilcapampa. We shot the long succession of rapids in the -first canyon without mishap, and at night pitched our tent on the edge -of the river near the mouth of the Manugali. - -From the sharp peak opposite our camp we saw for the first time the -phenomenon of cloud-banners. A light breeze was blowing from the western -mountains and its vapor was condensed into clouds that floated down the -wind and dissolved, while they were constantly forming afresh at the -summit. In the night a thunderstorm arose and swept with a roar through -the vast forest above us. The solid canopy of the tropical forest fairly -resounded with the impact of the heavy raindrops. The next morning all -the brooks from the farther side of the river were in flood and the -river discolored. When we broke camp the last mist wraiths of the storm -were still trailing through the tree-tops and wrapped about the peak -opposite our camp, only parting now and then to give us delightful -glimpses of a forest-clad summit riding high above the clouds. - -The alternation of deeps and shallows at this point in the river and the -well-developed canyon meanders are among the most celebrated of their -kind in the world. Though shut in by high cliffs and bordered by -mountains the river exhibits a succession of curves so regular that one -might almost imagine the country a plain from the pattern of the -meanders. The succession of smooth curves for a long distance across -existing mountains points to a time when a lowland plain with moderate -slopes drained by strongly meandering rivers was developed here. Uplift -afforded a chance for renewed down-cutting on the part of all the -streams, and the incision of the meanders. The present meanders are, of -course, not the identical ones that were formed on the lowland plain; -they are rather their descendants. Though they still retain their -strongly curved quality, and in places have almost cut through the -narrow spurs between meander loops, they are not smooth like the -meanders of the Mississippi. Here and there are sharp irregular turns -that mar the symmetry of the larger curves. The alternating bands of -hard and soft rock have had a large part in making the course more -irregular. The meanders have responded to the rock structure. Though -regular in their broader features they are irregular and deformed in -detail. - -Deeps and shallows are known in every vigorous river, but it is seldom -that they are so prominently developed as in these great canyons. At one -point in the upper canyon the river has been broadened into a lake two -or three times the average width of the channel and with a scarcely -perceptible current; above and below the "laguna," as the boatmen call -it, are big rapids with beds so shallow that rocks project in many -places. In the Pongo de Mainique the river is at one place only fifty -feet wide, yet so deep that there is little current. It is on the banks -of the quiet stretches that the red forest deer grazes under leafy -arcades. Here, too, are the boa-constrictor trails several feet wide and -bare like a roadway. At night the great serpents come trailing down to -the river's edge, where the red deer and the wildcat, or so-called -"tiger," are their easy prey. - -It is in such quiet stretches that one also finds the vast colonies of -water skippers. They dance continuously in the sun with an incessant -motion from right to left and back again. Occasionally one dances about -in circles, then suddenly darts through the entire mass, though without -striking his equally erratic neighbors. An up-and-down motion still -further complicates the effect. It is positively bewildering to look -intently at the whirling multitude and try to follow their complicated -motions. Every slight breath of wind brings a shock to the organization -of the dance. For though they dance only in the sun, their favorite -places are the sunny spots in the shade near the bank, as beneath an -overhanging tree. When the wind shakes the foliage the mottled pattern -of shade and sunlight is confused, the dance slows down, and the dancers -become bewildered. In a storm they seek shelter in the jungle. The hot, -quiet, sunlit days bring out literally millions of these tiny creatures. - -One of the longest deeps in the whole Urubamba lies just above the Pongo -at Mulanquiato. We drifted down with a gentle current just after sunset. -Shrill whistles, like those of a steam launch, sounded from either bank, -the strange piercing notes of the lowland cicada, _cicada tibicen_. Long -decorated canoes, better than any we had yet seen, were drawn up in the -quiet coves. Soon we came upon the first settlement. The owner, Señor -Pereira, has gathered about him a group of Machigangas, and by marrying -into the tribe has attained a position of great influence among the -Indians. Upon our arrival a gun was fired to announce to his people that -strangers had come, upon which the Machigangas strolled along in twos -and threes from their huts, helped us ashore with the baggage, and -prepared the evening meal. Here we sat down with five Italians, who had -ventured into the rubber fields with golden ideas as to profits. After -having lost the larger part of their merchandise, chiefly cinchona, in -the rapids the year before, they had established themselves here with -the idea of picking rubber. Without capital, they followed the ways of -the itinerant rubber picker and had gathered "caucho," the poorer of the -two kinds of rubber. No capital is required; the picker simply cuts down -the likeliest trees, gathers the coagulated sap, and floats it -down-stream to market. After a year of this life they had grown restless -and were venturing on other schemes for the great down-river rubber -country. - -[Illustration: FIG. 13--Composition of tropical vegetation in the rain -forest above Pongo de Mainique, elevation 2,500 feet (760 m.). Scores of -species occur within the limits of a single photograph.] - -[Illustration: FIG. 14--The mule trail in the rain forest between -Rosalina and Pongo de Mainique. Each pool is from one and a half to two -feet deep. Even in the dry season these holes are full of water, for the -sunlight penetrates the foliage at a few places only.] - -[Illustration: FIG. 15--Topography and vegetation from the Tocate pass, -7,100 feet (2,164 m.), between Rosalina and Pongo de Mainique. See Fig. -53a. This is in the zone of maximum rainfall. The cumulo-nimbus clouds -are typical and change to nimbus in the early afternoon.] - -[Illustration: FIG. 16--The Expedition's thirty-foot canoe at the mouth -of the Timpia below Pongo de Mainique.] - -A few weeks later, on returning through the forest, we met their -carriers with a few small bundles, the only part of their cargo they had -saved from the river. Without a canoe or the means to buy one they had -built rafts, which were quickly torn to pieces in the rapids. We, too, -should have said "_pobres Italianos_" if their venture had not been -plainly foolish. The rubber territory is difficult enough for men -with capital; for men without capital it is impossible. Such men either -become affiliated with organized companies or get out of the region when -they can. A few, made desperate by risks and losses, cheat and steal -their way to rubber. Two years before our trip an Italian had murdered -two Frenchmen just below the Pongo and stolen their rubber cargo, -whereupon he was shot by Machigangas under the leadership of Domingo, -the chief who was with us on a journey from Pongo de Mainique to the -mouth of the Timpia. Afterward they brought his skull to the top of a -pass along the forest trail and set it up on a cliff at the very edge of -Machiganga-land as a warning to others of his kind. - -At Mulanquiato we secured five Machigangas and a boy interpreter, and on -August 17 made the last and most difficult portion of our journey. We -found these Indians much more skilful than our earlier boatmen. -Well-trained, alert, powerful, and with excellent team-play, they swept -the canoe into this or that thread of the current, and took one after -another of the rapids with the greatest confidence. No sooner had we -passed the Sintulini rapids, fully a mile long, than we reached the -mouth of the Pomareni. This swift tributary comes in almost at right -angles to the main river and gives rise to a confusing mass of standing -waves and conflicting currents rendered still more difficult by the -whirlpool just below the junction. So swift is the circling current of -the maëlstrom that the water is hollowed out like a great bowl, a really -formidable point and one of our most dangerous passages; a little too -far to the right and we should be thrown over against the cliff-face; a -little too far to the left and we should be caught in the whirlpool. -Once in the swift current the canoe became as helpless as a chip. It was -turned this way and that, each turn heading it apparently straight for -destruction. But the Indians had judged their position well, and though -we seemed each moment in a worse predicament, we at last skimmed the -edge of the whirlpool and brought our canoe to shore just beyond its -rim. - -A little farther on we came to the narrow gateway of the Pongo, where -the entire volume of the river flows between cliffs at one point no -more than fifty feet apart. Here are concentrated the worst rapids of -the lower Urubamba. For nearly fifteen miles the river is an unbroken -succession of rapids, and once within its walls the Pongo offers small -chance of escape. At some points we were fortunate enough to secure a -foothold along the edge of the river and to let our canoe down by ropes. -At others we were obliged to take chances with the current, though the -great depth of water in most of the Pongo rapids makes them really less -formidable in some respects than the shallow rapids up stream. The chief -danger here lies in the rotary motion of the water at the sharpest -bends. The effect at some places is extraordinary. A floating object is -carried across stream like a feather and driven at express-train speed -against a solid cliff. In trying to avoid one of these cross-currents -our canoe became turned midstream, we were thrown this way and that, and -at last shot through three standing waves that half filled the canoe. - -Below the worst rapids the Pongo exhibits a swift succession of natural -wonders. Fern-clad cliffs border it, a bush resembling the juniper -reaches its dainty finger-like stems far out over the river, and the -banks are heavily clad with mosses. The great woods, silent, -impenetrable, mantle the high slopes and stretch up to the limits of -vision. Cascades tumble from the cliff summits or go rippling down the -long inclines of the slate beds set almost on edge. Finally appear the -white pinnacles of limestone that hem in the narrow lower entrance or -outlet of the Pongo. Beyond this passage one suddenly comes out upon the -edge of a rolling forest-clad region, the rubber territory, the country -of the great woods. Here the Andean realm ends and Amazonia begins. - -From the summits of the white cliffs 4,000 feet above the river we were -in a few days to have one of the most extensive views in South America. -The break between the Andean Cordillera and the hill-dotted plains of -the lower Urubamba valley is almost as sharp as a shoreline. The rolling -plains are covered with leagues upon leagues of dense, shadowy, -fever-haunted jungle. The great river winds through in a series of -splendid meanders, and with so broad a channel as to make it visible -almost to the horizon. Down river from our lookout one can reach ocean -steamers at Iquitos with less than two weeks of travel. It is three -weeks to the Pacific _via_ Cuzco and more than a month if one takes the -route across the high bleak lava-covered country which we were soon to -cross on our way to the coast at Camaná. - - - - -CHAPTER III - -THE RUBBER FORESTS - - -The white limestone cliffs at Pongo de Mainique are a boundary between -two great geographic provinces (Fig. 17). Down valley are the vast river -plains, drained by broad meandering rivers; up valley are the rugged -spurs of the eastern Andes and their encanyoned streams (Fig. 18). There -are outliers of the Andes still farther toward the northeast where hangs -the inevitable haze of the tropical horizon, but the country beyond them -differs in no important respect from that immediately below the Pongo. - -[Illustration: FIG. 17--Regional diagram of the Eastern Andes (here the -Cordillera Vilcapampa) and the adjacent tropical plains. For an -explanation of the method of construction and the symbolism of the -diagram see p. 51.] - -The foot-path to the summit of the cliffs is too narrow and steep for -even the most agile mules. It is simply impassable for animals without -hands. In places the packs are lowered by ropes over steep ledges and -men must scramble down from one projecting root or swinging vine to -another. In the breathless jungle it is a wearing task to pack in all -supplies for the station below the Pongo and to carry out the season's -rubber. Recently however the ancient track has been replaced by a road -that was cut with great labor, and by much blasting, across the mountain -barrier, and at last mule transport has taken the place of the Indian. - -[Illustration: FIG. 18--Index map for the nine regional diagrams in the -pages following. A represents Fig. 17; B, 42; C, 36; D, 32; E, 34; F, -25; G, 26; and H, 65.] - -In the dry season it is a fair and delightful country--that on the -border of the mountains. In the wet season the traveler is either -actually marooned or he must slosh through rivers of mud and water that -deluge the trails and break the hearts of his beasts (Fig. 14). Here and -there a large shallow-rooted tree has come crashing down across the -trail and with its four feet of circumference and ten feet of plank -buttress it is as difficult to move as a house. A new trail must be cut -around it. A little farther on, where the valley wall steepens and one -may look down a thousand feet of slope to the bed of a mountain torrent, -a patch of trail has become soaked with water and the mules pick their -way, trembling, across it. Two days from Yavero one of our mules went -over the trail, and though she was finally recovered she died of her -injuries the following night. After a month's work in the forest a mule -must run free for two months to recover. The packers count on losing one -beast out of five for every journey into the forest. It is not solely a -matter of work, though this is terrific; it is quite largely a matter of -forage. In spite of its profusion of life (Fig. 13) and its really vast -wealth of species, the tropical forest is all but barren of grass. Sugar -cane is a fair substitute, but there are only a few cultivated spots. -The more tender leaves of the trees, the young shoots of cane in the -_carrizo_ swamps, and the grass-like foliage of the low bamboo are the -chief substitutes for pasture. But they lead to various disorders, -besides requiring considerable labor on the part of the dejected peons -who must gather them after a day's heavy work with the packs. - -Overcoming these enormous difficulties is expensive and some one must -pay the bill. As is usual in a pioneer region, the native laborer pays a -large part of it in unrequited toil; the rest is paid by the rubber -consumer. For this is one of the cases where a direct road connects the -civilized consumer and the barbarous producer. What a story it could -tell if a ball of smoke-cured rubber on a New York dock were endowed -with speech--of the wet jungle path, of enslaved peons, of vile abuses -by immoral agents, of all the toil and sickness that make the tropical -lowland a reproach! - -[Illustration: FIG. 19--Moss-draped trees in the rain forest near Abra -Tocate between Rosalina and Pongo de Mainique.] - -[Illustration: FIG. 20--Yavero, a rubber station on the Yavero -(Paucartambo) River, a tributary of the Urubamba. Elevation 1,600 feet -(490 m.).] - -In the United States the specter of slavery haunted the national -conscience almost from the beginning of national life, and the ghost was -laid only at the cost of one of the bloodiest wars in history. In other -countries, as in sugar-producing Brazil, the freeing of the slaves meant -not a war but the verge of financial ruin besides a fundamental -change in the social order and problems as complex and wearisome as any -that war can bring. Everywhere abolition was secured at frightful cost. - -[Illustration: FIG. 21--Clearing in the tropical forest between Rosalina -and Pabellon. This represents the border region where the -forest-dwelling Machiganga Indians and the mountain Indians meet. The -clearings are occupied by Machigangas whose chief crops are yuca and -corn; in the extreme upper left-hand corner are grassy slopes occupied -by Quechua herdsmen and farmers who grow potatoes and corn.] - -The spirit that upheld the new founders of the western republics in -driving out slavery was admirable, but as much cannot be said of their -work of reconstruction. We like to pass over those dark days in our own -history. In South America there has lingered from the old slave-holding -days down to the present, a labor system more insidious than slavery, -yet no less revolting in its details, and infinitely more difficult to -stamp out. It is called peonage; it should be called slavery. In -Bolivia, Peru, and Brazil it flourishes now as it ever did in the -fruitful soil of the interior provinces where law and order are bywords -and where the scarcity of workmen will long impel men to enslave labor -when they cannot employ it. Peonage _is_ slavery, though as in all slave -systems there are many forms under which the system is worked out. We -commonly think that the typical slave is one who is made to work hard, -given but little food, and at the slightest provocation is tied to a -post and brutally whipped. This is indeed the fate of many slaves or -"peons" so-called, in the Amazon forests; but it is no more the rule -than it was in the South before the war, for a peon is a valuable piece -of property and if a slave raider travel five hundred miles through -forest and jungle-swamp to capture an Indian you may depend upon it that -he will not beat him to death merely for the fun of it. - -That unjust and frightfully cruel floggings are inflicted at times and -in some places is of course a result of the lack of official restraint -that drunken owners far from the arm of the law sometimes enjoy. When a -man obtains a rubber concession from the government he buys a kingdom. -Many of the rubber territories are so remote from the cities that -officials can with great difficulty be secured to stay at the customs -ports. High salaries must be paid, heavy taxes collected, and grafting -of the most flagrant kind winked at. Often the concessionaire himself is -chief magistrate of his kingdom by law. Under such a system, remote from -all civilizing influences, the rubber producer himself oftentimes a -lawless border character or a downright criminal, no system of -government would be adequate, least of all one like peonage that permits -or ignores flagrant wrongs because it is so expensive to enforce -justice. - -The peonage system continues by reason of that extraordinary difficulty -in the development of the tropical lowland of South America--the lack of -a labor supply. The population of Amazonia now numbers less than one -person to the square mile. The people are distributed in small groups of -a dozen to twenty each in scattered villages along the river banks or in -concealed clearings reached by trails known only to the Indians. Nearly -all of them still live in the same primitive state in which they lived -at the time of the Discovery. In the Urubamba region a single cotton -shirt is worn by the married men and women, while the girls and boys in -many cases go entirely naked except for a loincloth or a necklace of -nuts or monkeys' teeth (Fig. 23). A cane hut with a thatch to keep out -the heavy rains is their shelter and their food is the yuca, sugar cane, -Indian corn, bananas of many kinds, and fish. A patch of yuca once -planted will need but the most trifling attention for years. The small -spider monkey is their greatest delicacy and to procure it they will -often abandon every other project and return at their own sweet and -belated will. - -[Illustration: FIG. 22--Trading with Machiganga Indians in a reed swamp -at Santao Anato, Urubamba Valley, before Rosalina. Just outside the -picture on the right is a platform on which corn is stored for -protection against rodents and mildew. On the left is the corner of a -grass-thatched cane hut.] - -In the midst of this natural life of the forest-dwelling Indian appears -the rubber man, who, to gather rubber, must have rubber "pickers." If he -lives on the edge of the great Andean Cordillera, laborers may be -secured from some of the lower valleys, but they must be paid well for -even a temporary stay in the hot and unhealthful lowlands. Farther out -in the great forest country the plateau Indians will not go and only the -scattered tribes remain from which to recruit laborers. For the -nature-life of the Indian what has the rubber gatherer to offer? Money? -The Indian uses it for ornament only. When I once tried with money to -pay an Indian for a week's services he refused it. In exchange for his -severe labor he wanted nothing more than a fish-hook and a ring, the two -costing not more than a penny apiece! When his love for ornament has -once been gratified the Indian ceases to work. His food and shelter -and clothing are of the most primitive kind, but they are the best in -the world for him because they are the only kind he has known. So where -money and finery fail the lash comes in. The rubber man says that the -Indian is lazy and must be made to work; that there is a great deal of -work to be done and the Indian is the only laborer who can be found; -that if rubber and chocolate are produced the Indian must be made to -produce them; and that if he will not produce them for pay he must be -enslaved. - -[Illustration: FIG. 23--Ornaments and fabrics of the Machiganga Indians -at Yavero. The nuts are made up into strings, pendants, and heavy -necklaces. To the left of the center is one that contains feathers and -four drumsticks of a bird about the size of a small wild -turkey--probably the so-called turkey inhabiting the eastern mountain -valleys and the adjacent border of the plains, and hunted as an -important source of food. The cord in the upper right-hand corner is -used most commonly for heel supports in climbing trees. The openwork -sack is convenient for carrying game, fish, and fruit; the finely woven -sacks are used for carrying red ochre for ornamenting or daubing faces -and arms. They are also used for carrying corn, trinkets, and game.] - -It is a law of the rubber country that when an Indian falls into debt to -a white man he must work for the latter until the debt is discharged. If -he runs away before the debt is canceled or if he refuses to work or -does too little work he may be flogged. Under special conditions such -laws are wise. In the hands of the rubber men they are the basis of -slavery. For, once the rubber interests begin to suffer, the promoters -look around for a chance to capture free Indians. An expedition is -fitted out that spends weeks exploring this river or that in getting on -the track of unattached Indians. When a settlement is found the men are -enslaved and taken long distances from home finally to reach a rubber -property. There they are given a corner of a hut to sleep in, a few -cheap clothes, a rubber-picking outfit, and a name. In return for these -articles the unwilling Indian is charged any fanciful price that comes -into the mind of his "owner," and he must thereupon work at a per diem -wage also fixed by the owner. Since his obligations increase with time, -the Indian may die over two thousand dollars in debt! - -Peonage has left frightful scars upon the country. In some places the -Indians are fugitives, cultivating little farms in secreted places but -visiting them only at night or after carefully reconnoitering the spot. -They change their camps frequently and make their way from place to -place by secret trails, now spending a night or two under the shelter of -a few palm leaves on a sandbar, again concealing themselves in almost -impenetrable jungle. If the hunter sometimes discovers a beaten track he -follows it only to find it ending on a cliff face or on the edge of a -lagoon where concealment is perfect. There are tribes that shoot the -white man at sight and regard him as their bitterest enemy. Experience -has led them to believe that only a dead white is a good white, -reversing our saying about the North American Indian; and that even when -he comes among them on peaceful errands he is likely to leave behind him -a trail of syphilis and other venereal diseases scarcely less deadly -than his bullets. - -However, the peonage system is not hideous everywhere and in all its -aspects. There are white owners who realize that in the long run the -friendship of the Indians is an asset far greater than unwilling service -and deadly hatred. Some of them have indeed intermarried with the -Indians and live among them in a state but little above savagery. In the -Mamoré country are a few owners of original princely concessions who -have grown enormously wealthy and yet who continue to live a primitive -life among their scores of illegitimate descendants. The Indians look -upon them as benefactors, as indeed many of them are, defending the -Indians from ill treatment by other whites, giving them clothing and -ornaments, and exacting from them only a moderate amount of labor. In -some cases indeed the whites have gained more than simple gratitude for -their humane treatment of the Indians, some of whom serve their masters -with real devotion. - -When the "rubber barons" wish to discourage investigation of their -system they invite the traveler to leave and he is given a canoe and -oarsmen with which to make his way out of the district. Refusal to -accept an offer of canoes and men is a declaration of war. An agent of -one of the London companies accepted such a challenge and was promptly -told that he would not leave the territory alive. The threat would have -held true in the case of a less skilful man. Though Indians slept in the -canoes to prevent their seizure, he slipped past the guards in the -night, swam to the opposite shore, and there secured a canoe within -which he made a difficult journey down river to the nearest post where -food and an outfit could be secured. - -A few companies operating on or near the border of the Cordillera have -adopted a normal labor system, dependent chiefly upon people from the -plateau and upon the thoroughly willing assistance of well-paid forest -Indians. The Compañia Gomera de Mainique at Puerto Mainique just below -the Pongo is one of these and its development of the region without -violation of native rights is in the highest degree praiseworthy. In -fact the whole conduct of this company is interesting to a geographer, -as it reflects at every point the physical nature of the country. - -The government is eager to secure foreign capital, but in eastern Peru -can offer practically nothing more than virgin wealth, that is, land and -the natural resources of the land. There are no roads, virtually no -trails, no telegraph lines, and in most cases no labor. Since the old -Spanish grants ran at right angles to the river so as to give the owners -a cross-section of varied resources, the up-river plantations do not -extend down into the rubber country. Hence the more heavily forested -lower valleys and plains are the property of the state. A man can buy a -piece of land down there, but from any tract within ordinary means only -a primitive living can be obtained. The pioneers therefore are the -rubber men who produce a precious substance that can stand the enormous -tax on production and transportation. They do not want the land--only -the exclusive right to tap the rubber trees upon it. Thus there has -arisen the concession plan whereby a large tract is obtained under -conditions of money payment or of improvements that will attract -settlers or of a tax on the export. - -The "caucho" or poorer rubber of the Urubamba Valley begins at 3,000 -feet (915 m.) and the "hevea" or better class is a lower-valley and -plains product. The rubber trees thereabouts produce 60 grams (2 ozs.) -of dry rubber each week for eight months. After yielding rubber for this -length of time a tree is allowed to rest four or five years. "Caucho" is -produced from trees that are cut down and ringed with machetes, but it -is from fifty to sixty cents cheaper owing to the impurities that get -into it. The wood, not the nut, of the _Palma carmona_ is used for -smoking or "curing" the rubber. The government had long been urged to -build a road into the region in place of the miserable track--absolutely -impassable in the wet season--that heretofore constituted the sole -means of exit. About ten years ago Señor Robledo at last built a -government trail from Rosalina to Yavero about 100 miles long. While it -is a wretched trail it is better than the old one, for it is more direct -and it is better drained. In the wet season parts of it are turned into -rivers and lakes, but it is probably the best that could be done with -the small grant of twenty thousand dollars. - -With at least an improvement in the trail it became possible for a -rubber company to induce _cargadores_ or packers to transport -merchandise and rubber and to have a fair chance of success. Whereupon a -rubber company was organized which obtained a concession of 28,000 -hectares (69,188 acres) of land on condition that the company finish a -road one and one-half meters wide to the Pongo, connecting with the road -which the government had extended to Yavero. The land given in payment -was not continuous but was selected in lots by the company in such a way -as to secure the best rubber trees over an area several times the size -of the concession. The road was finished by William Tell after four -years' work at a cost of about seventy-five thousand dollars. The last -part of it was blasted out of slate and limestone and in 1912 the first -pack train entered Puerto Mainique. - -The first rubber was taken out in November, 1910, and productive -possibilities proved by the collection of 9,000 kilos (19,841 pounds) in -eight months. - -If a main road were the chief problem of the rubber company the business -would soon be on a paying basis, but for every mile of road there must -be cut several miles of narrow trail (Fig. 14), as the rubber trees grow -scattered about--a clump of a half dozen here and five hundred feet -farther on another clump and only scattered individuals between. -Furthermore, about twenty-five years ago rubber men from the Ucayali -came up here in launches and canoes and cut down large numbers of trees -within reach of the water courses and by ringing the trunks every few -feet with machetes "bled" them rapidly and thus covered a large -territory in a short time, and made huge sums of money when the price of -rubber was high. Only a few of the small trees that were left are now -mature. These, the mature trees that were overlooked, and the virgin -stands farther from the rivers are the present sources of rubber. - -In addition to the trails small cabins must be built to shelter the -hired laborers from the plateau, many of whom bring along their women -folk to cook for them. The combined expense to a company of these -necessary improvements before production can begin is exceedingly heavy. -There is only one alternative for the prospective exploiter: to become a -vagrant rubber gatherer. With tents, guns, machetes, cloth, baubles for -trading, tinned food for emergencies, and with pockets full of English -gold parties have started out to seek fortunes in the rubber forests. If -the friendship of a party of Indians can be secured by adequate gifts -large amounts of rubber can be gathered in a short time, for the Indians -know where the rubber trees grow. On the other hand, many fortunes have -been lost in the rubber country. Some of the tribes have been badly -treated by other adventurers and attack the newcomers from ambush or -gather rubber for a while only to overturn the canoe in a rapid and let -the river relieve them of selfish friends. - -The Compañia Gomera de Mainique started out by securing the good-will of -the forest Indians, the Machigangas. They come and go in friendly visits -to the port at Yavero. If one of them is sick he can secure free -medicine from the agent. If he wishes goods on credit he has only to ask -for them, for the agent knows that the Indian's sense of fairness will -bring him back to work for the company. Without previous notice a group -of Indians appears: - -"We owe," they announce. - -"Good," says the agent, "build me a house." - -They select the trees. Before they cut them down they address them -solemnly. The trees must not hold their destruction against the Indians -and they must not try to resist the sharp machetes. Then the Indians set -to work. They fell a tree, bind it with light ropes woven from the wild -cotton, and haul it to its place. That is all for the day. They play in -the sun, do a little hunting, or look over the agent's house, touching -everything, talking little, exclaiming much. They dip their wet fingers -in the sugar bowl and taste, turn salt out upon their hands, hold -colored solutions from the medicine chest up to the light, and pull out -and push in the corks of the bottles. At the end of a month or two the -house is done. Then they gather their women and babies together and say: - -"Now we go," without asking if the work corresponds with the cost of the -articles they had bought. Their judgment is good however. Their work is -almost always more valuable than the articles. Then they shake hands all -around. - -"We will come again," they say, and in a moment have disappeared in the -jungle that overhangs the trail. - -With such labor the Compañia Gomera de Mainique can do something, but it -is not much. The regular seasonal tasks of road-building and -rubber-picking must be done by imported labor. This is secured chiefly -at Abancay, where live groups of plateau Indians that have become -accustomed to the warm climate of the Abancay basin. They are employed -for eight or ten months at an average rate of fifty cents gold per day, -and receive in addition only the simplest articles of food. - -At the end of the season the gang leaders are paid a _gratificación_, or -bonus, the size of which depends upon the amount of rubber collected, -and this in turn depends upon the size of the gang and the degree of -willingness to work. In the books of the company I saw a record of -_gratificaciónes_ running as high as $600 in gold for a season's work. - -Some of the laborers become sick and are cared for by the agent until -they recover or can be sent back to their homes. Most of them have fever -before they return. - -The rubber costs the company two _soles_ ($1.00) produced at Yavero. The -two weeks' transportation to Cuzco costs three and a half soles ($1.75) -per twenty-five pounds. The exported rubber, known to the trade as -Mollendo rubber, in contrast to the finer "Pará" rubber from the lower -Amazon, is shipped to Hamburg. The cost for transportation from port to -port is $24.00 per English ton (1,016 kilos). There is a Peruvian tax of -8 per cent of the net value in Europe, and a territorial tax of two -soles ($1.00) per hundred pounds. All supplies except the few vegetables -grown on the spot cost tremendously. Even dynamite, hoes, clothing, -rice--to mention only a few necessities--must pay the heavy cost of -transportation after imposts, railroad and ocean freight, storage and -agents' percentages are added. The effect of a disturbed market is -extreme. When, in 1911, the price of rubber fell to $1.50 a kilo at -Hamburg the company ceased exporting. When it dropped still lower in -1912 production also stopped, and it is still doubtful, in view of the -growing competition of the East-Indian plantations with their cheap -labor, whether operations will ever be resumed. Within three years no -less than a dozen large companies in eastern Peru and Bolivia have -ceased operations. In one concession on the Madre de Dios the withdrawal -of the agents and laborers from the posts turned at last into flight, as -the forest Indians, on learning the company's policy, rapidly ascended -the river in force, committing numerous depredations. The great war has -also added to the difficulties of production. - -Facts like these are vital in the consideration of the future of the -Amazon basin and especially its habitability. It was the dream of -Humboldt that great cities should arise in the midst of the tropical -forests of the Amazon and that the whole lowland plain of that river -basin should become the home of happy millions. Humboldt's vision may -have been correct, though a hundred years have brought us but little -nearer its realization. Now, as in the past four centuries, man finds -his hands too feeble to control the great elemental forces which have -shaped history. The most he can hope for in the next hundred years at -least is the ability to dodge Nature a little more successfully, and -here and there by studies in tropical hygiene and medicine, by the -substitution of water-power for human energy, to carry a few of the -outposts and prepare the way for a final assault in the war against the -hard conditions of climate and relief. We hear of the Madeira-Mamoré -railroad, 200 miles long, in the heart of a tropical forest and of the -commercial revolution it will bring. Do we realize that the forest which -overhangs the rails is as big as the whole plain between the Rockies -and the Appalachians, and that the proposed line would extend only as -far as from St. Louis to Kansas City, or from Galveston to New Orleans? - -Even if twenty whites were eager to go where now there is but one -reluctant pioneer, we should still have but a halting development on -account of the scarcity of labor. When, three hundred years ago, the -Isthmus of Panama stood in his way, Gomara wrote to his king: "There are -mountains, but there are also hands," as if men could be conjured up -from the tropical jungle. From that day to this the scarcity of labor -has been the chief difficulty in the lowland regions of tropical South -America. Even when medicine shall have been advanced to the point where -residence in the tropics can be made safe, the Amazon basin will lack an -adequate supply of workmen. Where Humboldt saw thriving cities, the -population is still less than one to the square mile in an area as large -as fifteen of our Mississippi Valley states. We hear much about a rich -soil and little about intolerable insects; the climate favors a good -growth of vegetation, but a man can starve in a tropical forest as -easily as in a desert; certain tributaries of the Negro are bordered by -rich rubber forests, yet not a single Indian hut may be found along -their banks. Will men of the white race dig up the rank vegetation, -sleep in grass hammocks, live in the hot and humid air, or will they -stay in the cooler regions of the north and south? Will they rear -children in the temperate zones, or bury them in the tropics? - -What Gorgas did for Panama was done for intelligent people. Can it be -duplicated in the case of ignorant and stupid laborers? Shall the white -man with wits fight it out with Nature in a tropical forest, or fight it -out with his equals under better skies? - -The tropics must be won by strong hands of the lowlier classes who are -ignorant or careless of hygiene, and not by the khaki-clad robust young -men like those who work at Panama. Tropical medicine can do something -for these folk, but it cannot do much. And we cannot surround every -laborer's cottage with expensive screens, oiled ditches, and well-kept -lawns. There is a practical optimism and a sentimental optimism. The one -is based on facts; the other on assumptions. It is pleasant to think -that the tropical forest may be conquered. It is nonsense to say that we -are now conquering it in any comprehensive and permanent way. That sort -of conquest is still a dream, as when Humboldt wrote over a hundred -years ago. - - - - -CHAPTER IV - -THE FOREST INDIANS - - -The people of a tropical forest live under conditions not unlike those -of the desert. The Sahara contains 2,000,000 persons within its borders, -a density of one-half to the square mile. This is almost precisely the -density of population of a tract of equivalent size in the lowland -forests of South America. Like the oases groups in the desert of aridity -are the scattered groups along the river margins of the forest. The -desert trails run from spring to spring or along a valley floor where -there is seepage or an intermittent stream; the rivers are the highways -of the forest, the flowing roads, and away from them one is lost in as -true a sense as one may be lost in the desert. - -A man may easily starve in the tropical forest. Before starting on even -a short journey of two or three days a forest Indian stocks his canoe -with sugar cane and yuca and a little parched corn. He knows the -settlements as well as his desert brother knows the springs. The Pahute -Indian of Utah lives in the irrigated valleys and makes annual -excursions across the desert to the distant mountains to gather the -seeds of the nut pine. The Machiganga lives in the hills above the -Urubamba and annually comes down through the forest to the river to fish -during the dry season. - -The Machigangas are one of the important tribes of the Amazon basin. -Though they are dispersed to some extent upon the plains their chief -groups are scattered through the heads of a large number of valleys near -the eastern border of the Andes. Chief among the valleys they occupy are -the Pilcopata, Tono, Piñi-piñi, Yavero, Yuyato, Shirineiri, Ticumpinea, -Timpia, and Camisea (Fig. 203). In their distribution, in their -relations with each other, in their manner of life, and to some extent -in their personal traits, they display characteristics strikingly like -those seen in desert peoples. Though the forest that surrounds them -suggests plenty and the rivers the possibility of free movement with -easy intercourse, the struggle of life, as in the desert, is against -useless things. Travel in the desert is a conflict with heat and -aridity; but travel in the tropic forest is a struggle against space, -heat, and a superabundant and all but useless vegetation. - -The Machigangas are one of the subtribes of the Campas Indians, one of -the most numerous groups in the Amazon Valley. It is estimated that -there are in all about 14,000 to 16,000 of them. Each subtribe numbers -from one to four thousand, and the territory they occupy extends from -the limits of the last plantations--for example, Rosalina in the -Urubamba Valley--downstream beyond the edge of the plains. Among them -three subtribes are still hostile to the whites: the Cashibos, the -Chonta Campas, and the Campas Bravos. - -In certain cases the Cashibos are said to be anthropophagous, in the -belief that they will assume the strength and intellect of those they -eat. This group is also continuously at war with its neighbors, goes -naked, uses stone hatchets, as in ages past, because of its isolation -and unfriendliness, and defends the entrances to the tribal huts with -dart and traps. The Cashibos are diminishing in numbers and are now -scattered through the valley of the Gran Pajonal, the left bank of the -Pachitea, and the Pampa del Sacramento.[2] - -The friendliest tribes live in the higher valley heads, where they have -constant communication with the whites. The use of the bow and arrow has -not, however, been discontinued among them, in spite of the wide -introduction of the old-fashioned muzzle-loading shotgun, which they -prize much more highly than the latest rifle or breech-loading shotgun -because of its simplicity and cheapness. Accidents are frequent among -them owing to the careless use of fire-arms. On our last day's journey -on the Urubamba above the mouth of the Timpia one of our Indian boys -dropped his canoe pole on the hammer of a loaded shotgun, and not only -shot his own fingers to pieces, but gravely wounded his father (Fig. 2). -In spite of his suffering the old chief directed our work at the canoe -and even was able to tell us the location of the most favorable channel. -Though the night that followed was as black as ink, with even the stars -obscured by a rising storm, his directions never failed. We poled our -way up five long rapids without special difficulties, now working into -the lee of a rock whose location he knew within a few yards, now -paddling furiously across the channel to catch the upstream current of -an eddy. - -The principal groups of Machigangas live in the middle Urubamba and its -tributaries, the Yavero, Yuyato, Shirineiri, Ticumpinea, Timpia, -Pachitea, and others. There is a marked difference in the use of the -land and the mode of life among the different groups of this subtribe. -Those who live in the lower plains and river "playas," as the patches of -flood plain are called, have a single permanent dwelling and alternately -fish and hunt. Those that live on hill farms have temporary reed huts on -the nearest sandbars and spend the best months of the dry season--April -to October--in fishing and drying fish to be carried to their mountain -homes (Fig. 21). Some families even duplicate _chacras_ or farms at the -river bank and grow yuca and sugar cane. In latter years smallpox, -malaria, and the rubber hunters have destroyed many of the river -villages and driven the Indians to permanent residence in the hills or, -where raids occur, along secret trails to hidden camps. - -Their system of agriculture is strikingly adapted to some important -features of tropical soil. The thin hillside soils of the region are but -poorly stocked with humus, even in their virgin condition. Fallen trees -and foliage decay so quickly that the layer of forest mold is -exceedingly thin and the little that is incorporated in the soil is -confined to a shallow surface layer. To meet these special conditions -the Indian makes new clearings by girdling and burning the trees. When -the soil becomes worn out and the crops diminish, the old clearing is -abandoned and allowed to revert to natural growth and a new farm is -planted to corn and yuca. The population is so scattered and thin that -the land assignment system current among the plateau Indians is not -practised among the Machigangas. Several families commonly live together -and may be separated from their nearest neighbors by many miles of -forested mountains. The land is free for all, and, though some heavy -labor is necessary to clear it, once a small patch is cleared it is easy -to extend the tract by limited annual cuttings. Local tracts of -naturally unforested land are rarely planted, chiefly because the -absence of shade has allowed the sun to burn out the limited humus -supply and to prevent more from accumulating. The best soil of the -mountain slopes is found where there is the heaviest growth of timber, -the deepest shade, the most humus, and good natural drainage. It is the -same on the playas along the river; the recent additions to the flood -plain are easy to cultivate, but they lack humus and a fine matrix which -retains moisture and prevents drought or at least physiologic dryness. -Here, too, the timbered areas or the cane swamps are always selected for -planting. - -The traditions of the Machigangas go back to the time of the Inca -conquest, when the forest Indians, the "Antis," were subjugated and -compelled to pay tribute.[3] When the Inca family itself fled from Cuzco -after the Spanish Conquest and sought refuge in the wilderness it was to -the Machiganga country that they came by way of the Vilcabamba and -Pampaconas Valleys. Afterward came the Spaniards and though they did not -exercise governmental authority over the forest Indians they had close -relations with them. Land grants were made to white pioneers for special -services or through sale and with the land often went the right to -exploit the people on it. Some of the concessions were owned by people -who for generations knew nothing save by hearsay of the Indians who -dwelt in the great forests of the valleys. In later years they have been -exploring their lands and establishing so-called relations whereby the -savage "buys" a dollar's worth of powder or knives for whatever number -of dollars' worth of rubber the owner may care to extract from him. - -The forest Indian is still master of his lands throughout most of the -Machiganga country. He is cruelly enslaved at the rubber posts, held by -the loose bonds of a desultory trade at others, and in a few places, as -at Pongo do Mainique, gives service for both love and profit, but in -many places it is impossible to establish control or influence. The -lowland Indian never falls into the abject condition of his Quechua -brother on the plateau. He is self-reliant, proud, and independent. He -neither cringes before a white nor looks up to him as a superior being. -I was greatly impressed by the bearing of the first of the forest tribes -I met in August, 1911, at Santo Anato. I had built a brisk fire and was -enjoying its comfort when La Sama returned with some Indians whom he had -secured to clear his playa. The tallest of the lot, wearing a colored -band of deer skin around his thick hair and a gaudy bunch of yellow -feathers down his back, came up, looked me squarely in the eye, and -asked - -"Tatiry payta?" (What is your name?) - -When I replied he quietly sat down by the fire, helping himself to the -roasted corn I had prepared in the hot ashes. A few days later when we -came to the head of a rapid I was busy sketching-in my topographic map -and did not hear his twice repeated request to leave the boat while the -party reconnoitered the rapid. Watching his opportunity he came -alongside from the rear--he was steersman--and, turning just as he was -leaving the boat, gave me a whack in the forehead with his open palm. La -Sama saw the motion and protested. The surly answer was: - -"I twice asked him to get out and he didn't move. What does he think we -run the canoe to the bank for?" - -To him the making of a map was inexplicable; I was merely a stupid white -person who didn't know enough to get out of a canoe when told! - -The plateau Indian has been kicked about so long that all his -independence has been destroyed. His goods have been stolen, his -services demanded without recompense, in many places he has no right to -land, and his few real rights are abused beyond belief. The difference -between him and the forest Indian is due quite largely to differences of -environment. The plateau Indian is agricultural, the forest Indian -nomadic and in a hunting stage of development; the unforested plateau -offers no means for concealment of person or property, the forest offers -hidden and difficult paths, easy means for concealment, for ambush, and -for wide dispersal of an afflicted tribe. The brutal white of the -plateau follows altogether different methods when he finds himself in -the Indian country, far from military assistance, surrounded by fearless -savages. He may cheat but he does not steal, and his brutality is always -carefully suited to both time and place. - -The Machigangas are now confined to the forest, but the limits of their -territory were once farther upstream, where they were in frequent -conflict with the plateau Indians. As late as 1835, according to General -Miller,[4] they occupied the land as far upstream as the "Encuentro" -(junction) of the Urubamba and the Yanatili (Fig. 53). Miller likewise -notes that the Chuntaguirus, "a superior race of Indians" who lived -"toward the Marañon," came up the river "200 leagues" to barter with the -people thereabouts. - -"They bring parrots and other birds, monkeys, cotton robes white and -painted, wax balsams, feet of the gran bestia, feather ornaments for the -head, and tiger and other skins, which they exchange for hatchets, -knives, scissors, needles, buttons, and any sort of glittering bauble." - -On their yearly excursions they traveled in a band numbering from 200 to -300, since at the mouth of the Paucartambo (Yavero) they were generally -set upon by the Pucapacures. The journey upstream required three months; -with the current they returned home in fifteen days. - -Their place of meeting at the mouth of the Yanatili was a response to a -long strip of grassland that extends down the deep and dry Urubamba -Valley, as shown in Figs. 53-B and 55. The wet forests, in which the -Machigangas live, cover the hills back of the valley plantations; the -belt of dry grassland terminates far within the general limits of the -red man's domain and only 2,000 feet above the sea. It is in this strip -of low grassland that on the one hand the highland and valley dwellers, -and on the other the Indians of the hot forested valleys and the -adjacent lowland found a convenient place for barter. The same -physiographic features are repeated in adjacent valleys of large size -that drain the eastern aspect of the Peruvian Andes, and in each case -they have given rise to the periodic excursions of the trader. - -These annual journeys are no longer made. The planters have crept down -valley. The two best playas below Rosalina are now being cleared. Only a -little space remains between the lowest valley plantations and the -highest rubber stations. Furthermore, the Indians have been enslaved by -the rubber men from the Ucayali. The Machigangas, many of whom are -runaway peons, will no longer take cargoes down valley for fear of -recapture. They have the cautious spirit of fugitives except in their -remote valleys. There they are secure and now and then reassert their -old spirit when a lawless trader tries to browbeat them into an -unprofitable trade. Also, they are yielding to the alluring call of the -planter. At Santo Anato they are clearing a playa in exchange for -ammunition, machetes, brandy, and baubles. They no longer make annual -excursions to get these things. They have only to call at the nearest -plantation. There is always a wolf before the door of the planter--the -lack of labor. Yet, as on every frontier, he turns wolf himself when the -lambs come, and without shame takes a week's work for a penny mirror, -or, worse still, supplies them with firewater, for that will surely -bring them back to him. Since this is expensive they return to their -tribal haunts with nothing except a debauched spirit and an appetite -from which they cannot run away as they did from their task masters in -the rubber forest. Hence the vicious circle: more brandy, more labor; -more labor, more cleared land; more cleared land, more brandy; more -brandy, less Indian. But by that time the planter has a large sugar -estate. Then he can begin to buy the more expensive plateau labor, and -in turn debauch it. - -Nature as well as man works against the scattered tribes of Machigangas -and their forest kinsmen. Their country is exceedingly broken by -ramifying mountain spurs and valleys overhung with cliffs or bordered by -bold, wet, fern-clad slopes. It is useless to try to cut your way by a -direct route from one point to another. The country is mantled with -heavy forest. You must follow the valleys, the ancient trails of the -people. The larger valleys offer smooth sand-bars along the border of -which canoes may be towed upstream, and there are little cultivated -places for camps. But only a few of the tribes live along them, for they -are also more accessible to the rubbermen. The smaller valleys, -difficult of access, are more secure and there the tribal remnants live -today. While the broken country thus offers a refuge to fugitive bands -it is the broken country and its forest cover that combine to break up -the population into small groups and keep them in an isolated and -quarrelsome state. Chronic quarreling is not only the product of mere -lack of contact. It is due to many causes, among which is a union of the -habit of migration and divergent tribal speech. Every tribe has its own -peculiar words in addition to those common to the group of tribes to -which it belongs. Moreover each group of a tribe has its distinctive -words. I have seen and used carefully prepared vocabularies--no two of -which are alike throughout. They serve for communication with only a -limited number of families. These peculiarities increase as experiences -vary and new situations call for additions to or changes in their -vocabularies, and when migrating tribes meet their speech may be so -unlike as to make communication difficult. Thus arise suspicion, -misunderstanding, plunder, and chronic war. Had they been a united -people their defense of their rough country might have been successful. -The tribes have been divided and now and again, to get firearms and -ammunition with which to raid a neighbor, a tribe has joined its -fortunes to those of vagrant rubber pickers only to find in time that -its women were debased, its members decimated by strange and deadly -diseases, and its old morality undermined by an insatiable desire for -strong drink.[5] The Indian loses whether with the white or against him. - -The forest Indian is held by his environment no less strongly than the -plateau Indian. We hear much about the restriction of the plateau -dweller to the cool zone in which the llama may live. As a matter of -fact he lives far below the cool zone, where he no longer depends upon -the llama but rather upon the mule for transport. The limits of his -range correspond to the limits of the grasslands in the dry valley -pockets already described (p. 42), or on the drier mountain slopes below -the zone of heaviest rainfall (Fig. 54). It is this distribution that -brought him into such intimate contact with the forest Indian. The old -and dilapidated coca terraces of the Quechuas above the Yanatili almost -overlook the forest patches where the Machigangas for centuries built -their rude huts. A good deal has been written about the attempts of the -Incas to extend their rule into this forest zone and about the failure -of these attempts on account of the tropical climate. But the forest -Indian was held by bonds equally secure. The cold climate of the plateau -repelled him as it does today. His haunts are the hot valleys where he -need wear only a wild-cotton shirt or where he may go naked altogether. -That he raided the lands of the plateau Indian is certain, but he could -never displace him. Only along the common borders of their domains, -where the climates of two zones merged into each other, could the forest -Indian and the plateau Indian seriously dispute each other's claims to -the land. Here was endless conflict but only feeble trade and only the -most minute exchanges of cultural elements. - -Even had they been as brothers they would have had little incentive to -borrow cultural elements from each other. The forest dweller requires -bow and arrow; the plateau dweller requires a hoe. There are fish in the -warm river shallows of the forested zone; llamas, vicuña, vizcachas, -etc., are a partial source of food supply on the plateau. Coca and -potatoes are the chief products of the grassy mountain slopes; yuca, -corn, bananas, are the chief vegetable foods grown on the tiny -cultivated patches in the forest. The plateau dweller builds a -thick-walled hut; the valley dweller a cane shack. So unlike are the two -environments that it would be strange if there had been a mixture of -racial types and cultures. The slight exchanges that were made seem -little more than accidental. Even today the Machigangas who live on the -highest slopes own a few pigs obtained from Quechuas, but they never eat -their flesh; they keep them for pets merely. I saw not a single woolen -article among the Indians along the Urubamba whereas Quechuas with -woolen clothing were going back and forth regularly. Their baubles were -of foreign make; likewise their few hoes, likewise their guns. - -They clear the forest about a mid-cotton tree and spin and weave the -cotton fiber into sacks, cords for climbing trees when they wish to -chase a monkey, ropes for hauling their canoes, shirts for the married -men and women, colored head-bands, and fish nets. The slender strong -bamboo is gathered for arrows. The chunta palm, like bone for hardness, -supplies them with bows and arrow heads. The brilliant red and yellow -feathers of forest birds, also monkey bones and teeth, are their natural -ornaments. Their life is absolutely distinct from that of their Quechua -neighbors. Little wonder that for centuries forest and plateau Indians -have been enemies and that their cultures are so distinct, for their -environment everywhere calls for unlike modes of existence and distinct -cultural development. - - - - -CHAPTER V - -THE COUNTRY OF THE SHEPHERDS - - -The lofty mountain zones of Peru, the high bordering valleys, and the -belts of rolling plateau between are occupied by tribes of shepherds. In -that cold, inhospitable region at the top of the country are the highest -permanent habitations in the world--17,100 feet (5,210 m.)--the loftiest -pastures, the greatest degree of adaptation to combined altitude and -frost. It is here only a step from Greenland to Arcady. Nevertheless it -is Greenland that has the people. Why do they shun Arcady? To the -traveler from the highlands the fertile valleys between 5,000 and 8,000 -feet (1,500 to 2,500 m.) seem like the abode of friendly spirits to -whose charm the highland dweller must yield. Every pack-train from -valley to highland carries luxury in the form of fruit, coca, cacao, and -sugar. One would think that every importation of valley products would -be followed by a wave of migration from highland to valley. On the -contrary the highland people have clung to their lofty pastures for -unnumbered centuries. Until the Conquest the last outposts of the Incas -toward the east were the grassy ridges that terminate a few thousand -feet below the timber line. - -In this natural grouping of the people where does choice or blind -prejudice or instinct leave off? Where does necessity begin? There are -answers to most of these questions to be found in the broad field of -geographic comparison. But before we begin comparisons we must study the -individual facts upon which they rest. These facts are of almost every -conceivable variety. They range in importance from a humble shepherd's -stone corral on a mountain slope to a thickly settled mountain basin. -Their interpretation is to be sought now in the soil of rich playa -lands, now in the fixed climatic zones and rugged relief of deeply -dissected, lofty highlands in the tropics. Some of the controlling -factors are historical, others economic; still other factors have -exerted their influence through obscure psychologic channels almost -impossible to trace. The _why_ of man's distribution over the earth is -one of the most complicated problems in natural science, and the -solution of it is the chief problem of the modern geographer. - -At first sight the mountain people of the Peruvian Andes seem to be -uniform in character and in mode of life. The traveler's first -impression is that the same stone-walled, straw-thatched type of hut is -to be found everywhere, the same semi-nomadic life, the same degrees of -poverty and filth. Yet after a little study the diversity of their lives -is seen to be, if not a dominating fact, at least one of surprising -importance. Side by side with this diversity there runs a corresponding -diversity of relations to their physical environment. Nowhere else on -the earth are greater physical contrasts compressed within such small -spaces. If, therefore, we accept the fundamental theory of geography -that there is a general, necessary, varied, and complex relation between -man and the earth, that theory ought here to find a really vast number -of illustrations. A glance at the accompanying figures discloses the -wide range of relief in the Peruvian Andes. The corresponding range in -climate and in life therefore furnishes an ample field for the -application of the laws of human distribution. - -In analyzing the facts of distribution we shall do well to begin with -the causes and effects of migration. Primitive man is in no small degree -a wanderer. His small resources often require him to explore large -tracts. As population increases the food quest becomes more intense, and -thus there come about repeated emigrations which increase the food -supply, extend its variety, and draw the pioneers at last into contact -with neighboring groups. The farther back we go in the history of the -race the clearer it becomes that migrations lie at the root of much of -human development. The raid for plunder, women, food, beasts, is a -persistent feature of the life of those primitive men who live on the -border of unlike regions. - -The shepherd of the highland and the forest hunter of the plains -perforce range over vast tracts, and each brings back to the home group -news that confirms the tribal choice of habitation or sets it in motion -toward a more desirable place. Superstitions may lead to flight akin to -migration. Epidemics may be interpreted as the work of a malignant -spirit from which men must flee. War may drive a defeated group into the -fastnesses of a mountain forest where pursuit by stream or trail weakens -the pursuer and confines his action, thereby limiting his power. Floods -may come and destroy the cultivated spots. Want or mere desire in a -hundred forms may lead to movement. - -Even among forest tribes long stationary the facile canoe and the light -household necessities may easily enable trivial causes to develop the -spirit of restlessness. Pressure of population is a powerful but not a -general cause of movement. It may affect the settled groups of the -desert oases, or the dense population of fertile plains that is rooted -in the soil. On the other hand mere whims may start a nomadic group -toward a new goal. Often the goal is elusive and the tribe turns back to -the old haunts or perishes in the shock of unexpected conflict. - -In the case of both primitive societies and those of a higher order the -causes and the results of migration are often contradictory. These will -depend on the state of civilization and the extremes of circumstance. -When the desert blooms the farmer of the Piura Valley in northwestern -Peru turns shepherd and drives his flocks of sheep and goats out into -the short-lived pastures of the great pampa on the west. In dry years he -sends them eastward into the mountains. The forest Indian of the lower -Urubamba is a fisherman while the river is low and lives in a reed hut -beside his cultivated patch of cane and yuca. When the floods come he is -driven to the higher ground in the hills where he has another cultivated -patch of land and a rude shelter. To be sure, these are seasonal -migrations, yet through them the country becomes better known to each -new generation of men. And each generation supplies its pioneers, who -drift into the remoter places where population is scarce or altogether -wanting. - -[Illustration: FIG. 24--This stone hut, grass-thatched, is the highest -permanent habitation in Peru, and is believed to be the highest in the -world. Altitude of 17,100 feet (5,210 m.) determined by instrumental -survey. The general geographic relationships of the region in which the -hut is situated are shown in Fig. 25. For location see the topographic -map, Fig. 204.] - -Dry years and extremely dry years may have opposite effects. When -moderate dryness prevails the results may be endurable. The oases -become crowded with men and beasts just when they can ill afford to -support them. The alfalfa meadows become overstocked and cattle become -lean and almost worthless. But there is at least bare subsistence. By -contrast, if extreme and prolonged drought prevails, some of the people -are driven forth to more favored spots. At Vallenar in central Chile -some of the workmen in extreme years go up to the nitrate pampa; in wet -years they return. When the agents of the nitrate companies hear of hard -times in a desert valley they offer employment to the stricken people. -It not infrequently happens that when there are droughts in desert Chile -there are abundant rains in Argentina on the other side of the -Cordillera. There has therefore been for many generations an irregular -and slight, though definite, shifting of population from one side of the -mountains to the other as periods of drought and periods of rain -alternated in the two regions. Some think there is satisfactory evidence -to prove that a number of the great Mongolian emigrations took place in -wet years when pasture was abundant and when the pastoral nomad found it -easy to travel. On the other hand it has been urged that the cause of -many emigrations was prolonged periods of drought when the choice lay -between starvation and flight. It is evident from the foregoing that -both views may be correct in spite of the fact that identical effects -are attributed to opposite causes. - -[Illustration: FIG. 25--Regional diagram for the Maritime Cordillera to -show the physical relations in the district where the highest habitation -in the world are located. For location, see Fig. 20. It should be -remembered that the orientation of these diagrams is generalized. By -reference to Fig. 20 it will be seen that some portions of the crest of -the Maritime Cordillera run east and west and others north and south. -The same is true of the Cordillera Vilcapampa, Fig. 36.] - - _Note on regional diagrams._--For the sake of clearness I have - classified the accompanying facts of human distribution in the - country of the shepherds and represented them graphically in - "regional" diagrams, Figs. 17, 25, 26, 32, 34, 36, 42, 65. These - diagrams are constructed on the principle of dominant control. Each - brings out the factors of greatest importance in the distribution - of the people in a given region. Furthermore, the facts are - compressed within the limits of a small rectangle. This - compression, though great, respects all essential relations. For - example, every location on these diagrams has a concrete - illustration but the accidental relations of the field have been - omitted; the essential relations are preserved. Each diagram is, - therefore, a kind of generalized type map. It bears somewhat the - same relation to the facts of human geography that a block diagram - does to physiography. The darkest shading represents steep - snow-covered country; the next lower grade represents rough but - snow-free country; the lightest shading represents moderate relief; - unshaded parts represent plain or plateau. Small circles represent - forest or woodland; small open-spaced dots, grassland. Fine - alluvium is represented by small closely spaced dots; coarse - alluvium by large closely spaced dots. - - To take an illustration. In Figure 32 we have the Apurimac region - near Pasaje (see location map, Fig. 20). At the lower edge of the - rectangle is a snow-capped outlier of the Cordillera Vilcapampa. - The belt of rugged country represents the lofty, steep, exposed, - and largely inaccessible ridges at the mid-elevations of the - mountains below the glaciated slopes at the heads of tributary - valleys. The villages in the belt of pasture might well be - Incahuasi and Corralpata. The floors of the large canyons on either - hand are bordered by extensive alluvial fans. The river courses are - sketched in a diagrammatic way only, but a map would not be - different in its general disposition. Each location is justified by - a real place with the same essential features and relations. In - making the change there has been no alteration of the general - relation of the alluvial lands to each other or to the highland. By - suppressing unnecessary details there is produced a diagram whose - essentials have simple and clear relations. When such a regional - diagram is amplified by photographs of real conditions it becomes a - sort of generalized picture of a large group of geographic facts. - One could very well extend the method to the whole of South - America. It would be a real service to geography to draw up a set - of, say, twelve to fifteen regional diagrams, still further - generalized, for the whole of the continent. As a broad - classification they would serve both the specialist and the general - student. As the basis for a regional map of South America they - would be invaluable if worked out in sufficient detail and - constructed on the indispensable basis of field studies. - -It is still an open question whether security or insecurity is more -favorable for the broad distribution of the Peruvian Indians of the -mountain zone which forms the subject of this chapter. Certainly both -tend to make the remoter places better known. Tradition has it that, in -the days of intertribal conflict before the Conquest, fugitives fled -into the high mountain pastures and lived in hidden places and in caves. -Life was insecure and relief was sought in flight. On the other hand -peace has brought security to life. The trails are now safe. A shepherd -may drive his flock anywhere. He no longer has any one to fear in his -search for new pastures. It would perhaps be safe to conclude that there -is equally broad distribution of men in the mountain pastures in time of -peace and in time of war. There is, however, a difference in the kind -of distribution. In time of peace the individual is safe anywhere; in -time of unrest he is safe only when isolated and virtually concealed. By -contrast, the group living near the trails is scattered by plundering -bands and war parties. The remote and isolated group may successfully -oppose the smaller band and the individuals that might reach the remoter -regions. The fugitive group would have nothing to fear from large bands, -for the limited food supply would inevitably cause these to disintegrate -upon leaving the main routes of travel. Probably the fullest exploration -of the mountain pastures has resulted from the alternation of peace and -war. The opposite conditions which these establish foster both kinds of -distribution; hence both the remote group life encouraged by war and the -individual's lack of restraint in time of peace are probably in large -part responsible for the present widespread occupation of the Peruvian -mountains. - -The loftiest habitation in the world (Fig. 24) is in Peru. Between -Antabamba and Cotahuasi occur the highest passes in the Maritime -Cordillera. We crossed at 17,400 feet (5,300 m.), and three hundred feet -lower is the last outpost of the Indian shepherds. The snowline, very -steeply canted away from the sun, is between 17,200 and 17,600 feet -(5,240 to 5,360 m.). At frequent intervals during the three months of -winter, snowfalls during the night and terrific hailstorms in the late -afternoon drive both shepherds and flocks to the shelter of leeward -slopes or steep canyon walls. At our six camps, between 16,000 and -17,200 feet (4,876 and 5,240 m.), in September, 1911, the minimum -temperature ranged from 4° to 20°F. The thatched stone hut that we -passed at 17,100 feet and that enjoys the distinction of being the -highest in the world was in other respects the same as the thousands of -others in the same region. It sheltered a family of five. As we passed, -three rosy-cheeked children almost as fat as the sheep about them were -sitting on the ground in a corner of the corral playing with balls of -wool. Hundreds of alpacas and sheep grazed on the hill slopes and valley -floor, and their tracks showed plainly that they were frequently driven -up to the snowline in those valleys where a trickle of water supported a -band of pasture. Less than a hundred feet below them were other huts and -flocks. - -Here we have the limits of altitude and the limits of resources. The -intervalley spaces do not support grass. Some of them are quite bare, -others are covered with mosses. It is too high for even the tola -bush--that pioneer of Alpine vegetation in the Andes. The distance[6] to -Cotahuasi is 75 miles (120 km.), to Antabamba 50 miles (80 km.). Thence -wool must be shipped by pack-train to the railroad in the one case 250 -miles (400 km.) to Arequipa, in the other case 200 miles (320 km.) to -Cuzco. Even the potatoes and barley, which must be imported, come from -valleys several days' journey away. The question naturally arises why -these people live on the rim of the world. Did they seek out these -neglected pastures, or were they driven to them? Do they live here by -choice or of necessity? The answer to these questions introduces two -other geographic factors of prime importance, the one physical, the -other economic. - -The main tracts of lofty pasture above Antabamba cover mountain slopes -and valley floor alike, but the moist valley floors supply the best -grazing. Moreover, the main valleys have been intensively glaciated. -Hence, though their sides are steep walls, their floors are broad and -flat. Marshy tracts, periodically flooded, are scattered throughout, and -here and there are overdeepened portions where lakes have gathered. -There is a thick carpet of grass, also numerous huts and corrals, and -many flocks. At the upper edge of the main zone of pasture the grasses -become thin and with increasing altitude give out altogether except -along the moist valley floors or on shoulders where there is seepage. - -If the streams head in dry mountain slopes without snow the grassy bands -of the valley floor terminate at moderate elevations. If the streams -have their sources in snowfields or glaciers there is a more uniform -run-off, and a ribbon of pasture may extend to the snowline. To the -latter class belong the pastures that support these remote people. - -In the case of the Maritime Andes the great elevation of the snowline is -also a factor. If, in Figure 25, we think of the snowline as at the -upper level of the main zone of pasture then we should have the -conditions shown in Figure 36, where the limit of general, not local, -occupation is the snowline, as in the Cordillera Vilcapampa and between -Chuquibambilla and Antabamba. - -A third factor is the character of the soil. Large amounts of volcanic -ash and lapilli were thrown out in the late stages of volcanic eruption -in which the present cones of the Maritime Andes were formed. The coarse -texture of these deposits allows the ready escape of rainwater. The -combination of extreme aridity and great elevation results in a double -restraint upon vegetation. Outside of the moist valley floors, with -their film of ground moraine on whose surface plants find a more -congenial soil, there is an extremely small amount of pasture. Here are -the natural grazing grounds of the fleet vicuña. They occur in -hundreds, and so remote and little disturbed are they that near the main -pass one may count them by the score. As we rode by, many of them only -stared at us without taking the trouble to get beyond rifle shot. It is -not difficult to believe that the Indians easily shoot great numbers in -remote valleys that have not been hunted for years. - -The extreme conditions of life existing on these lofty plateaus are well -shown by the readiness with which even the hardy shepherds avail -themselves of shelter. Wherever deep valleys bring a milder climate -within reach of the pastures the latter are unpopulated for miles on -either side. The sixty-mile stretch between Chuquibamba and Salamanca is -without even a single hut, though there are pastures superior to the -ones occupied by those loftiest huts of all. Likewise there are no -permanent homes between Salamanca and Cotahuasi, though the shepherds -migrate across the belt in the milder season of rain. Eastward and -northward toward the crest of the Maritime Cordillera there are no huts -within a day's journey of the Cotahuasi canyon. Then there is a group of -a dozen just under the crest of the secondary range that parallels the -main chain of volcanoes. Thence northward there are a number of -scattered huts between 15,500 and 16,500 feet (4,700 and 5,000 m.), -until we reach the highest habitations of all at 17,100 feet (5,210m.). - -[Illustration: FIG. 26--Regional diagram to show the physical relations -in the lava plateau of the Maritime Cordillera west of the continental -divide. For location, see Fig. 20. Trails lead up the intrenched -tributaries. If the irrigated bench (lower right corner) is large, a -town will be located on it. Shepherds' huts are scattered about the edge -of the girdle of spurs. There is also a string of huts in the deep -sheltered head of each tributary. See also Fig. 29 for conditions on the -valley or canyon floor.] - -The unpopulated belts of lava plateau bordering the entrenched valleys -are, however, as distinctly "sustenance" spaces, to use Penck's term, as -the irrigated and fertile alluvial fans in the bottom of the valley. -This is well shown when the rains come and flocks of llamas and sheep -are driven forth from the valleys to the best pastures. It is equally -well shown by the distribution of the shepherds' homes. These are not -down on the warm canyon floor, separated by a half-day's journey from -the grazing. They are in the intrenched tributary valleys of Figure 26 -or just within the rim of the canyon. It is not shelter from the cold -but from the wind that chiefly determines their location. They are also -kept near the rim of the canyon by the pressure of the farming -population from below. Every hundred feet of descent from the arid -plateau (Fig. 29) increases the water supply. Springs increase in number -and size; likewise belts of seepage make their appearance. The gradients -in many places diminish, and flattish spurs and shoulders interrupt the -generally steep descents of the canyon wall. Every change of this sort -has a real value to the farmer and means an enhanced price beyond the -ability of the poor shepherd to pay. If you ask a wealthy _hacendado_ on -the valley floor (Fig. 29), who it is that live in the huts above him, -he will invariably say "los Indios," with a shrug meant to convey the -idea of poverty and worthlessness. Sometimes it is "los Indios pobres," -or merely "los pobres." Thus there is a vertical stratification of -society corresponding to the superimposed strata of climate and land. - -At Salamanca (Fig. 62) I saw this admirably displayed under -circumstances of unusual interest. The floor and slopes of the valley -are more completely terraced than in any other valley I know of. In the -photograph, Fig. 30, which shows at least 2,500 feet of descent near the -town, one cannot find a single patch of surface that is not under -cultivation. The valley is simply filled with people to the limit of its -capacity. Practically all are Indians, but with many grades of wealth -and importance. When we rode out of the valley before daybreak, one -September morning in 1911, there was a dead calm, and each step upward -carried us into a colder stratum of air. At sunrise we had reached a -point about 2,000 feet above the town, or 14,500 feet (4,420 m.) above -sea level. We stood on the frost line. On the opposite wall of the -valley the line was as clearly marked out as if it had been an -irrigating canal. The light was so fully reflected from the millions of -frost crystals above it that both the mountainside and the valley slopes -were sparkling like a ruffled lake at sunrise. Below the frost line the -slopes were dark or covered with yellow barley and wheat stubble or -green alfalfa. - -It happened that the frost line was near the line of division between -corn and potato cultivation and also near the line separating the steep -rough upper lands from the cultivable lower lands. Not a habitation was -in sight above us, except a few scattered miserable huts near broken -terraces, gullied by wet-weather streams and grown up to weeds and -brush. Below us were well-cultivated fields, and the stock was kept in -bounds by stone fences and corrals; above, the half-wild burros and -mules roamed about everywhere, and only the sheep and llamas were in -rude enclosures. Thus in a half hour we passed the frontier between the -agricultural folk below the frost line and the shepherd folk above it. - -[Illustration: FIG. 27--Terraced valley slopes at Huaynacotas, Cotahuasi -Valley, Peru. Elevation 11,500 feet (3,500 m.).] - -[Illustration: FIG. 28--The highly cultivated and thoroughly terraced -floor of the Ollantaytambo Valley at Ollantaytambo. This is a tributary -of the Urubamba; elevation, 11,000 feet.] - -[Illustration: FIG. 29--Cotahuasi on the floor of the Cotahuasi canyon. -The even skyline of the background is on a rather even-topped lava -plateau. The terrace on the left of the town is formed on limestone, -which is overlain by lava flows. A thick deposit of terraced alluvium -may be seen on the valley floor, and it is on one of the lower terraces -that the city of Cotahuasi stands. The higher terraces are in many cases -too dry for cultivation. The canyon is nearly 7,000 feet (2,130 m.) deep -and has been cut through one hundred principal lava flows.] - -In a few spots the line followed an irregular course, as where flatter -lands were developed at unusual elevations or where air drainage altered -the normal temperature. And at one place the frost actually stood on -the young corn, which led us to speculate on the possibility of securing -from Salamanca a variety of maize that is more nearly resistant to light -frosts than any now grown in the United States. In the endless and -largely unconscious experimentation of these folk perched on the valley -walls a result may have been achieved ahead of that yet reached by our -professional experimenters. Certain it is that nowhere else in the world -has the potato been grown under such severe climatic conditions as in -its native land of Peru and Bolivia. The hardiest varieties lack many -qualities that we prize. They are small and bitter. But at least they -will grow where all except very few cultivated plants fail, and they are -edible. Could they not be imported into Canada to push still farther -northward the limits of cultivation? Potatoes are now grown at Forts -Good Hope and McPherson in the lower Mackenzie basin. Would not the -hardiest Peruvian varieties grow at least as far north as the -continental timber line? I believe they could be grown still farther -north. They will endure repeated frosts. They need scarcely any -cultivation. Prepared in the Peruvian manner, as _chuño_, they could be -kept all winter. Being light, the meal derived from them could be easily -packed by hunters and prospectors. An Indian will carry in a pouch -enough to last him a week. Why not use it north of the continental limit -of other cultivated plants since it is the pioneer above the frost line -on the Peruvian mountains? - -The relation between farmer and shepherd or herdsman grows more complex -where deeper valleys interrupt the highlands and mountains. The -accompanying sketch, Fig. 32, represents typical relations, though based -chiefly on the Apurimac canyon and its surroundings near Pasaje. First -there is the snow-clad region at the top of the country. Below it are -grassy slopes, the homes of mountain shepherds, or rugged mountain -country unsuited for grazing. Still lower there is woodland, in patches -chiefly, but with a few large continuous tracts. The shady sides of the -ravines and the mountains have the most moisture, hence bear the densest -growths. Finally, the high country terminates in a second belt of -pasture below the woodland. - -[Illustration: FIG. 32--Regional diagram representing the deep canyoned -country west of the Eastern Cordillera in the region of the Apurimac. -For photograph see Fig. 94. For further description see note on regional -diagrams, p. 51. Numbers 1, 2, and 3 correspond in position to the same -numbers in Fig. 33.] - -[Illustration: FIG. 30--Terraced hill slopes near Salamanca. There is no -part of the photograph which is not covered with terraces save a few -places where bushy growths are visible or where torrents descend through -artificial canals.] - -[Illustration: FIG. 31--Alpine pastures in the mountain valley between -Chuquibambilla and Lambrama. Huge stone corrals are built on either -slope, sheltered from the night winds that blow down-valley.] - -Whenever streams descend from the snow or woodland country there is -water for the stock above and for irrigation on the alluvial fan below. -But the spur ends dropping off abruptly several thousand feet have a -limited area and no running streams, and the ground water is hundreds of -feet down. There is grass for stock, but there is no water. In some -places the stock is driven back and forth every few days. In a few -places water is brought to the stock by canal from the woodland streams -above, as at Corralpata.[7] In the same way a canal brings water to -Pasaje hacienda from a woodland strip many miles to the west. The little -canal in the figure is almost a toy construction a few inches wide and -deep and conveying only a trickle of water. Yet on it depends the -settlement at the spur end, and if it were cut the people would have to -repair it immediately or establish new homes. - -[Illustration: FIG. 33--Valley climates of the canyoned region shown in -Fig. 32.] - -The canal and the pasture are possible because the slopes are moderate. -They were formed in an earlier cycle of erosion when the land was lower. -They are hung midway between the rough mountain slopes above and the -steep canyon walls below (Fig. 32). Their smooth descents and gentle -profiles are in very pleasing contrast to the rugged scenery about them. -The trails follow them easily. Where the slopes are flattest, farmers -have settled and produce good crops of corn, vegetables, and barley. -Some farmers have even developed three-and four-story farms. On an -alluvial fan in the main valley they raise sugar cane and tropical and -subtropical fruits; on the flat upper slopes they produce corn; in the -moister soil near the edge of the woodland are fields of mountain -potatoes; and the upper pastures maintain flocks of sheep. In one -district this change takes place in a distance that may be covered in -five hours. Generally it is at least a full and hard day's journey from -one end of the series to the other. - -Wherever these features are closely associated they tend to be -controlled by the planter in some deep valley thereabouts. Where they -are widely scattered the people are independent, small groups living in -places nearly inaccessible. Legally they are all under the control of -the owners of princely tracts that take in the whole country, but the -remote groups are left almost wholly to themselves. In most cases they -are supposed to sell their few commercial products to the _hacendado_ -who nominally owns their land, but the administration of this -arrangement is left largely to chance. The shepherds and small farmers -near the plantation are more dependent upon the planter for supplies, -and also their wants are more varied and numerous. Hence they pay for -their better location in free labor and in produce sold at a discount. - -So deep are some of the main canyons, like the Apurimac and the -Cotahuasi, that their floors are arid or semi-arid. The fortunes of -Pasaje are tied to a narrow canal from the moist woodland and a tiny -brook from a hollow in the valley wall. Where the water has thus been -brought down to the arable soil of the fans there are rich plantations -and farms. Elsewhere, however, the floor is quite dry and uncultivated. -In small spots here and there is a little seepage, or a few springs, or -a mere thread of water that will not support a plantation, wherefore -there have come into existence the valley herdsmen and shepherds. Their -intimate knowledge of the moist places is their capital, quite as much -as are the cattle and sheep they own. In a sense their lands are the -neglected crumbs from the rich man's table. So we find the shepherd from -the hills invading the valleys just as the valley farmer has invaded the -country of the shepherd. - -[Illustration: FIG. 34--Regional diagram to show the typical physical -conditions and relations in an intermont basin in the Peruvian Andes. -The Cuzco basin (see Fig. 37) is an actual illustration; it should, -however, be emphasized that the diagram is not a "map" of that basin, -for whilst conditions there have been utilized as a basis, the -generalization has been extended to illustrate many basins.] - -The basin type of topography calls into existence a set of relations -quite distinct from either of those we have just described. Figure 34 -represents the main facts. The rich and comparatively flat floor of the -basin supports most of the people. The alluvial fans tributary thereto -are composed of fine material on their outer margin and of coarse stony -waste at their heads. Hence the valley farms also extend over the edges -of the fans, while only pasture or dense chaparral occupies the upper -portions. Finally there is the steep margin of the basin where the -broad and moderate slopes of the highland break down to the floor of the -basin. - -[Illustration: FIG. 35--Climatic cross-section showing the location of -various zones of cultivation and pasture in a typical intermont basin in -the Peruvian Andes. The thickness of the dark symbols on the right is -proportional to the amount of each staple that is produced at the -corresponding elevation. See also the regional diagram Fig. 34.] - -If a given basin lies at an elevation exceeding 14,000 feet (4,270 m.), -there will be no cultivation, only pasture. If at 10,000 or 11,000 feet -(3,000 or 3,350 m.), there will be grain fields below and potato fields -above (Figs. 34 and 35). If still lower, fruit will come in and finally -sugar cane and many other subtropical products, as at Abancay. Much will -also depend upon the amount of available water and the extent of the -pasture land. Thus the densely populated Cuzco basin has a vast mountain -territory tributary to it and is itself within the limits of barley and -wheat cultivation. Furthermore there are a number of smaller basins, -like the Anta basin on the north, which are dependent upon its better -markets and transportation facilities. A dominance of this kind is -self-stimulating and at last is out of all proportion to the original -differences of nature. Cuzco has also profited as the gateway to the -great northeastern valley region of the Urubamba and its big -tributaries. All of the varied products of the subtropical valleys find -their immediate market at Cuzco. - -The effect of this natural conspiracy of conditions has been to place -the historic city of Cuzco in a position of extraordinary importance. -Hundreds of years before the Spanish Conquest it was a center of -far-reaching influence, the home of the powerful Inca kings. From it the -strong arm of authority and conquest was extended; to it came tribute -of grain, wool, and gold. To one accustomed to look at such great -consequences as having at least some ultimate connection with the earth, -the situation of Cuzco would be expected to have some unique features. -With the glorious past of that city in mind, no one can climb to the -surrounding heights and look down upon the fertile mountain-rimmed plain -as at an ordinary sight (Fig. 37). The secret of those great conquests -lies not only in mind but in matter. If the rise of the Incas to power -was not related to the topography and climate of the Cuzco basin, at -least it is certain that without so broad and noble a stage the scenes -would have been enacted on a far different scale. - -The first Inca king and the Spanish after the Incas found here no mobile -nomadic tribes melting away at the first touch, no savages hiding in -forest fastnesses, but a well-rooted agricultural race in whose center a -large city had grown up. Without a city and a fertile tributary plain no -strong system of government could be maintained or could even arise. It -is a great advantage in ruling to have subjects that cannot move. The -agricultural Indians of the Andean valleys and basins, in contrast to -the mobile shepherd, are as fixed as the soil from which they draw their -life. - -The full occupation of the pasture lands about the Cuzco basin is in -direct relation to the advantages we have already enumerated. Every part -of the region feels the pressure of population. Nowhere else in the -Peruvian Andes are the limits between cultivation and grazing more -definitely drawn than here. Moreover, there is today a marked difference -between the types that inhabit highland and basin. The basin Indian is -either a debauched city dweller or, as generally, a relatively alert -farmer. The shepherds are exceedingly ignorant and live for the most -part in a manner almost as primitive as at the time of the Conquest. -They are shy and suspicious. Many of them prefer a life of isolation and -rarely go down to the town. They live on the fringe of culture. The new -elements of their life have come to them solely by accident and by what -might be called a process of ethnic seepage. The slight advances that -have been made do not happen by design, they merely happen. Put the -highland shepherd in the basin and he would starve in competition with -the basin type. Undoubtedly he would live in the basin if he could. He -has not been driven out of the basin; he is kept out. - -And thus it is around the border of the Abancay basin and others like -it. Only, the Abancay basin is lower and more varied as to resources. -The Indian is here in competition with the capitalistic white planter. -He lives on the land by sufferance alone. Farther up the slopes are the -farms of the Indians and above them are the pastures of the ignorant -shepherds. Whereas the Indian farmer who raises potatoes clings chiefly -to the edge of the Cuzco basin where lie the most undesirable -agricultural lands, the Indian farmers of Abancay live on broad rolling -slopes like those near the pass northward toward Huancarama. They are -unusually prosperous, with fields so well cultivated and fenced, so -clean and productive, that they remind one somewhat of the beautiful -rolling prairies of Iowa. - -It remains to consider the special topographic features of the mountain -environments we are discussing, in the Vilcapampa region on the eastern -border of the Andes (Fig. 36). The Cordillera Vilcapampa is -snow-crested, containing a number of fine white peaks like Salcantay, -Soray, and Soiroccocha (Fig. 140). There are many small glaciers and a -few that are several miles long. There was here in glacial times a much -larger system of glaciers, which lived long enough to work great changes -in the topography. The floors of the glaciated valleys were smoothed and -broadened and their gradients flattened (Figs. 137 and 190). The side -walls were steepened and precipitous cirques were formed at the valley -heads. Also, there were built across the valleys a number of stony -morainic ridges. With all these changes there was, however, but little -effect upon the main masses of the big intervalley spurs. They remain as -before--bold, wind-swept, broken, and nearly inaccessible. - -[Illustration: FIG. 36--Regional diagram for the Eastern Cordillera or -Cordillera Vilcapampa. Note the crowded zones on the right (east and -north) in contrast to the open succession on the left. In sheltered -places woodland extends even higher than shown. At several points -patches of it grow right under the snowline. Other patches grow on the -floors of the glaciated valley troughs.] - -The work of the glaciers aids the mountain people. The stony moraines -afford them handy sizable building material for their stone huts and -their numerous corrals. The thick tufts of grass in the marshy spots in -the overdeepened parts of the valleys furnish them with grass for their -thatched roofs. And, most important of all, the flat valley floors have -the best pasture in the whole mountain region. There is plenty of water. -There is seclusion, and, if a fence be built from one valley wall to -another as can be done with little labor, an entire section of the -valley may be inclosed. A village like Choquetira, located on a bench on -the valley side, commands an extensive view up and down the valley--an -important feature in a grazing village where the corrals cannot always -be built near the houses of the owners. Long, finger-like belts of -highland-shepherd population have thus been extended into the mountain -valleys. Sheep and llamas drift right up to the snowline. - -There is, however, a marked difference between the people on opposite -sides of the Cordillera Vilcapampa. On the west the mountains are -bordered by a broad highland devoted to grazing. On the east there is a -narrower grazing belt leading abruptly down to tropical valleys. The -eastern or leeward side is also the warmer and wetter side of the -Cordillera. The snowline is several hundred feet lower on the east. The -result is that patches of scrub and even a little woodland occur almost -at the snowline in favored places. Mist and storms are more frequent. -The grass is longer and fresher. Vegetation in general is more abundant. -The people make less of wool than of cattle, horses, and mules. -Vilcabamba pueblo is famous for its horses, wiry, long-haired little -beasts, as hardy as Shetland ponies. We found cattle grazing only five -hundred feet below the limit of perpetual snow. There are cultivated -spots only a little farther down, and only a thousand feet below the -snow are abandoned terraces. At the same elevation are twisted quenigo -trees, at least two hundred years old, as shown by their rings of -growth. Thus the limits of agriculture are higher on the east; likewise -the limits of cattle grazing that naturally goes with agriculture. Sheep -would thrive, but llamas do better in drier country, and the shepherd -must needs mix his flocks, for the wool which is his chief product -requires transportation and only the cheap and acclimated llama is at -the shepherd's disposal. From these facts it will be seen that the -anthropo-geographic contrasts between the eastern and western sides of -the Cordillera Vilcapampa are as definite as the climatic and vegetal -contrasts. This is especially well shown in the differences between dry -Arma, deep-sunk in a glaciated valley west of the crest of the -mountains, and wet Puquiura, a half-day's journey east of the crest. -There is no group on the east at all comparable to the shepherds of -Choquetira, either in the matter of thorough-going dependence upon -grazing or in that of dependence upon glacial topography. - -[Illustration: FIG. 37--Cuzco and a portion of the famous Cuzco basin -with bordering grassy highlands.] - -[Illustration: FIG. 38--Terraced valley slopes and floor, Urubamba -Valley between Urubamba and Ollantaytambo.] - -[Illustration: FIG. 39--Huichihua, near Chuquibambilla, a typical -mountain village, in the valleys of the Central Ranges, Peruvian Andes.] - -[Illustration: FIG. 40--Potato fluid above Vilcabamba at 12,000 feet -(3,660 m.). The natural sod is broken by a steel-shod stick and the seed -potato dropped into a mere puncture. It receives no attention thereafter -until harvest time.] - -Topography is not always so intimately related to the life of the people -as here. In our own country the distribution of available water is a far -greater factor. The Peruvian Andes therefore occupy a distinctive place -in geography, since, more nearly than in most mountains, their physical -conditions have typical human relations that enable one clearly to -distinguish the limits of control of each feature of climate or relief. - - - - -CHAPTER VI - -THE BORDER VALLEYS OF THE EASTERN ANDES - - -[Illustration: FIG. 41--Regional diagram of the eastern aspect of the -Cordillera Vilcapampa. See also Fig. 17 of which this is an enlarged -section.] - -On the northeastern border of the Peruvian Andes long mountain spurs -trail down from the regions of snow to the forested plains of the -Amazon. Here are the greatest contrasts in the physical and human -geography of the Andean Cordillera. So striking is the fact that every -serious student of Peru finds himself compelled to cross and recross -this natural frontier. The thread of an investigation runs irregularly -now into one border zone, now into another. Out of the forest came the -fierce marauders who in the early period drove back the Inca pioneers. -Down into the forest to escape from the Spaniards fled the last Inca and -his fugitive court. Here the Jesuit fathers sowed their missions along -the forest margin, and watched over them for two hundred years. From the -mountain border one rubber project after another has been launched into -the vast swampy lowlands threaded by great rivers. As an ethnic boundary -the eastern mountain border of Peru and Bolivia has no equal elsewhere -in South America. From the earliest antiquity the tribes of the -grass-covered mountains and the hordes of the forested plains have had -strongly divergent customs and speech, that bred enduring hatred and led -to frequent and bloody strife. - -[Illustration: FIG. 42--Rug weaver at Cotahuasi. The industry is limited -to a small group of related families, living in the Cotahuasi Canyon -near Cotahuasi. The rugs are made of alpaca wool. Pure black, pure -white, and various shades of mixed gray wool are employed. The result is -that the rugs have "fast" colors that always retain their original -contrasts. They are made only to order at the homes of the purchasers. -The money payment is small, but to it is added board and lodging, -besides tobacco, liqueurs, and wine. Before drinking they dip their -finger-tips in the wine and sprinkle the earth "that it may be -fruitful," the air "that it may be warm," the rug "that it may turn out -well," and finally themselves, making the sign of the cross. Then they -set to work.] - -[Illustration: FIG. 43--The floor of the Urubamba Valley from Tarai. The -work of the glaciers was not confined to the lofty situations. Mountain -débris was delivered to all the streams, many of which aggraded their -floors to a depth of several hundred feet, thus increasing the extent of -arable soil at elevations where a less rigorous climate permits the -production of crops and encourages intensive cultivation.] - -On the steepest spurs of the Pampaconas Valley the traveler may go from -snow to pasture in a half day and from pasture to forest in the same -time. Another day he is in the hot zone of the larger valley floors, the -home of the Machigangas. The steep descents bring out the superimposed -zones with diagrammatic simplicity. The timber line is as sharply marked -as the edge of a cultivated field. At a point just beyond the huts of -Pampaconas one may stand on a grassy spur that leads directly up--a -day's journey--to the white summits of the Cordillera Vilcapampa. Yet so -near him is the edge of the forest that he is tempted to try to throw a -stone into it. In an hour a bitter wind from the mountains may drive him -to shelter or a cold fog come rolling up from the moist region below. It -is hard to believe that oppressive heat is felt in the valley just -beneath him. - -In the larger valleys the geographic contrasts are less sharp and the -transition from mountains to plain, though less spectacular, is much -more complex and scientifically interesting. The forest types -interfinger along the shady and the sunny slopes. The climate is so -varied that the forest takes on a diversified character that makes it -far more useful to man. The forest Indians and the valley planters are -in closer association. There are many islands and peninsulas of plateau -population on the valley floor. Here the zones of climate and the belts -of fertile soil have larger areas and the land therefore has greater -economic value. Much as the valley people need easier and cheaper -communication with the rest of Peru it is no exaggeration to say that -the valley products, are needed far more by the coast and plateau -peoples to make the republic self-supporting. Coca, wood, sugar, fruit, -are in such demand that their laborious and costly transportation from -the valleys to the plateau is now carried on with at least some profit -to the valley people. Improved transportation would promote travel and -friendship and supply a basis for greater political unity. - -A change in these conditions is imminent. Years ago the Peruvian -government decreed the construction of a railway from Cuzco to Santa Ana -and preliminary surveys were made but without any immediate practical -effect. By June, 1914, 12.4 miles (20 km.) had been opened to traffic. -The total length of the proposed line is 112 miles (180 km.), the gauge -is to be only 2.46 feet (75 cm.),[8] and the proposed cost several -millions of dollars. The financial problem may be solved either by a -diversion of local revenues, derived from taxes on coca and alcohol, or -by borrowed foreign capital guaranteed by local revenues. - -A shrubby vegetation is scattered along the valley from the village of -Urubamba, 12,000 feet (3,658 m.) above sea level, to the Canyon of -Torontoy. It is local and of little value. Trees appear at -Ollantaytambo, 11,000 feet (3,353 m.), and here too are more extensive -wheat and maize fields besides throngs of cacti and great patches of -wild geraniums. On our valley journey we camped in pleasant fields -flanked by steep hills whose summits each morning were tipped with snow. -Enormous alluvial fans have partly filled up the valleys and furnished -broad tracts of fertile soil. The patient farmers have cleared away the -stones on the flatter portions and built retaining walls for the smooth -fields required for irrigation. In places the lower valley slopes are -terraced in the most regular manner (Fig. 38). Some of the fans are too -steep and stony for cultivation, exposing bare tracts which wash down -and cover the fields. Here and there are stone walls built especially to -retain the rush of mud and stones that the rains bring down. Many of -them were overthrown or completely buried. Unless the stream channels on -the fans are carefully watched and effective works kept up, the labor of -years may be destroyed in a single slide from the head of a steep fan. - -Each group of fans has a population proportioned to its size and -fertility. If there are broad expanses a town like Urubamba or a great -hacienda like Huadquiña is sure to be found. One group of huge stony -fans below Urubamba (Fig. 180) has only a thin population, for the soil -is coarse and infertile and the rivers deeply intrenched. In some places -the tiny fans perched high upon the flanks of the mountains where little -tributaries burst out of steep ravines are cultivated by distant owners -who also till parts of the larger fans on the main valley floors. -Between the fans of the valley bottoms and the smooth slopes of the high -plateaus are the unoccupied lands--the steep canyon walls. Only in the -most highly favored places where a small bench or a patch of alluvium -occurs may one find even an isolated dwelling. The stair-like trails, in -some places cut in solid rock, zigzag up the rocky slopes. An ascent of -a thousand feet requires about an hour's travel with fresh beasts. The -valley people are therefore walled in. If they travel it is surely not -for pleasure. Even business trips are reduced to the smallest number. -The prosperity and happiness of the valley people are as well known -among the plateau people as is their remarkable bread. Their climate has -a combination of winter rain and winter cold with light frosts that is -as favorable for good wheat as the continuous winter cold and snow cover -of our northern Middle West. The colder grainfields of the plateau are -sowed to barley chiefly, though there is also produced some wheat. -Urubamba wheat and bread are exported in relatively large quantities, -and the market demands greater quantities than the valley can supply. -Oregon and Washington flour are imported at Cuzco, two days' muleback -journey from the wheat fields of Urubamba. - -Such are the conditions in the upper Urubamba Valley. The lower valley, -beginning at Huadquiña, is 8,000 feet (2,440 m.) above sea level and -extends down to the two-thousand-foot contour at Rosalina and to one -thousand feet (305 m.) at Pongo de Mainique. The upper and lower -sections are only a score of miles (30 km.) apart between Huadquiña and -Torontoy, but there is a difference in elevation of three thousand feet -(915 m.) at just the level where the maximum contrasts are produced. The -cold timber line is at 10,500 feet (3,200 m.).[9] Winter frosts are -common at the one place; they are absent altogether at the other. -Torontoy produces corn; Huadquiña produces sugar cane. - -These contrasts are still further emphasized by the sharp topographic -break between the two unlike portions of the valley. A few miles below -Torontoy the Urubamba plunges into a mile-deep granite canyon. The walls -are so close together that it is impossible from the canyon floor to get -into one photograph the highest and steepest walls. At one place there -is over a mile of descent in a horizontal distance of 2,000 feet. Huge -granite slabs fall off along joint planes inclined but 15° from the -vertical. The effect is stupendous. The canyon floor is littered with -coarse waste and the gradient of the river greatly steepened. There is -no cultivation. The trees cling with difficulty to patches of rock waste -or to the less-inclined slopes. There is a thin crevice vegetation that -outlines the joint pattern where seepage supplies the venturesome roots -with moisture. Man has no foothold here, save at the top of the country, -as at Machu Picchu, a typical fortress location safeguarded by the -virtually inaccessible canyon wall and connected with the main ridge -slopes only by an easily guarded narrow spur. Toward the lower end of -the canyon a little finer alluvium appears and settlement begins. -Finally, after a tumble of three thousand feet over countless rapids the -river emerges at Colpani, where an enormous mass of alluvium has been -dumped. The well-intrenched river has already cut a large part of it -away. A little farther on is Huadquiña in the Salcantay Valley, where a -tributary of the Urubamba has built up a sheet of alluvial land, bright -green with cane. From the distant peaks of Salcantay and its neighbors -well-fed streams descend to fill the irrigation channels. Thus the snow -and rock-waste of the distant mountains are turned into corn and sugar -on the valley lowlands. - -[Illustration: FIG. 44--The snow-capped Cordillera Vilcapampa north of -Yucay and the upper canyon of the Urubamba from the wheat fields near -Chinchero. In the foreground is one of the well-graded mature slopes of -Fig. 123. The crests of the mountains lie along the axis of a granite -intrusion. The extent of the snowfields is extraordinary in view of the -low latitude, 13° S.] - -[Illustration: FIG. 45--Rounded slopes due to glacial action at -Pampaconas in the Pampaconas Valley near Vilcabamba. A heavy tropical -forest extends up the Pampaconas Valley to the hill slopes in the -background. Its upper limit of growth is about 10,000 feet (3,050 m.). -The camera is pointed slightly downhill.] - -[Illustration: FIG. 46--Hacienda Huadquiña in the Salcantay Valley a -short distance above its junction with the Urubamba, elevation 8,000 -feet (2,440 m.). The cultivated fields are all planted to sugar cane. -The mountain slopes are devoted to grazing.] - -The Cordillera Vilcapampa is a climatic as well as a topographic -barrier. The southwestern aspect is dry; the northeastern aspect -forested. The gap of the canyon, it should be noticed, comes at a -critical level, for it falls just above the upper border of the zone of -maximum precipitation. The result is that though mists are driven -through the canyon by prolonged up-valley winds, they scatter on -reaching the plateau or gather high up on the flanks of the valley or -around the snowy peaks overlooking the trail between Ollantaytambo and -Urubamba. The canyon walls are drenched with rains and even some of the -lofty spurs are clothed with dense forest or scrub. - -Farther down the valley winds about irregularly, now pushed to one side -by a huge alluvial fan, now turned by some resistant spur of rock. -Between the front range of the Andes and the Cordillera Vilcapampa there -is a broad stretch of mountain country in the lee of the front range -which rises to 7,000 feet (2,134 m.) at Abra Tocate (Fig. 15), and falls -off to low hills about Rosalina. It is all very rough in that there are -nowhere any flats except for the narrow playa strips along the streams. -The dense forest adds to the difficulty of movement. In general -appearance it is very much like the rugged Cascade country of Oregon -except that the Peruvian forest is much more patchy and its trees are in -many places loaded with dense dripping moss which gives the landscape a -somber touch quite absent from most of the forests of the temperate -zone. - -The fertility of the eastern valleys of Peru--the result of a union of -favorable climate and alluvial soil--has drawn the planter into this -remote section of the country, but how can he dispose of his products? -Even today with a railway to Cuzco from the coast it is almost -impossible for him to get his sugar and cacao to the outside world.[10] -How did he manage before even this railway was built? How could the -eastern valley planter live before there were any railways at all in -Peru? In part he has solved the problem as the moonshiner of Kentucky -tried to solve it, and from cane juice makes aguardiente (brandy). The -latter is a much more valuable product than sugar, hence (1) it will -bear a higher rate of transportation, or (2) it will at the same rate of -transportation yield a greater net profit. In a remote valley where -sugar could not be exported on account of high freight rates brandy -could still be profitably exported. - -The same may be said for coca and cacao. They are condensed and valuable -products. Both require more labor than sugar but are lighter in bulk and -thus have to bear, in proportion to their value, a smaller share of the -cost of transportation. At the end of three years coca produces over a -ton of leaves per acre per year, and it can be made to produce as much -as two tons to the acre. The leaves are picked four times a year. They -are worth from eight to twelve cents gold a pound at the plantation or -sixteen cents a pound at Cuzco. An orchard of well-cultivated and -irrigated cacao trees will do even better. Once they begin to bear the -trees require relatively little care except in keeping out weeds and -brush and maintaining the water ditches. However, the pods must be -gathered at just the right time, the seeds must be raked and dried with -expert care, and after that comes the arduous labor of the grinding. -This is done by hand on an inclined plane with a heavy round stone whose -corners fit the hand. The chocolate must then be worked into cakes and -dried, or it must be sacked in heavy cowhide and sewed so as to be -practically air tight. When eight or ten years old the trees are mature -and each may then bear a thousand pounds of seed. - -[Illustration: FIG. 47--The Urubamba Valley below Paltaybamba. Harder -rocks intruded into the schists that in general compose the valley walls -here form steep scarps. It has been suggested (Davis) that such a -constricted portion of a valley be called a "shut-in." The old trail -climbed to the top of the valley and over the back of a huge spur. The -new road is virtually a tunnel blasted along the face of a cliff.] - -[Illustration: FIG 48--Coca seed beds near Quillabamba, Urubamba Valley. -The young plants are grown under shade and after attaining a height of a -foot or more are gradually accustomed to sunlight and finally -transplanted to the fields that are to become coca orchards.] - -If labor were cheap and abundant the whole trend of tropical agriculture -in the eastern valleys would be toward intensive cultivation and the -production of expensive exports. But labor is actually scarce. Every -planter must have agents who can send men down from the plateau towns. -And the planter himself must use his labor to the best advantage. -Aguardiente requires less labor than cacao and coca. The cane costs -about as much in labor the first year as the coca bush or the cacao -tree, but after that much less. The manufacture of brandy from the cane -juice requires little labor though much expensive machinery. For -chocolate, a storehouse, a grinding stone, and a rake are all that -are required. So the planter must work out his own salvation -individually. He must take account of the return upon investments in -machinery, of the number of hands he can command from among the "faena" -or free Indians, of the cost and number of imported hands from the -valley and plateau towns, and, finally, of the transportation rates -dependent upon the number of mules in the neighborhood, and distance -from the market. If in addition the labor is skilfully employed so as to -have the tasks which the various products require fall at different -periods of the year, then the planter may expect to make money upon his -time and get a return upon his initial investment in the land.[11] - -[Illustration: FIG. 49--Fig tree formerly attached to a host but now -left standing on its stilt-like aërial roots owing to the decay of the -host.] - -[Illustration: FIG. 50--A tiny rubber plant is growing under the tripod -made of yuca stems tied with banana leaves. Growing yuca is shown by the -naked stalks to the left and right of this canopy, and banana plants -fill the background. A plantation scene at Echarati.] - -The type of tropical agriculture which we have outlined is profitable -for the few planters who make up the white population of the valleys, -but it has a deplorable effect upon the Indian population. Though the -planters, one and all, complain bitterly of the drunken habits of their -laborers, they themselves put into the hands of the Indians the means of -debauchery. Practically the whole production of the eastern valleys is -consumed in Peru. What the valleys do not take is sent to the plateau, -where it is the chief cause of vicious conduct. Two-thirds of the -prisoners in the city jails are drunkards, and, to be quite plain, they -are virtually supplied with brandy by the planter, who could not -otherwise make enough money. So although the planter wants more and -better labor he is destroying the quality of the little there is, and, -if not actually reducing the quantity of it, he is at least very -certainly reducing the rate of increase. - -The difficulties of the valley planter could be at least partly overcome -in several ways. The railway will reduce transportation costs, -especially when the playas of the valleys are all cleared and the -exports increased. Moreover the eastern valleys are capable of -producing things of greater utility than brandy and coca leaves. So far -as profits are increased by cheaper transportation we may expect the -planter to produce more rather than less of brandy and coca, his two -most profitable exports, unless other products can be found that are -still more profitable. The ratio of profits on sugar and brandy will -still be the same unless the government increases the tax on brandy -until it becomes no more profitable than sugar. That is what ought to be -done for the good of the Indian population. It cannot be done safely -without offering in its place the boon of cheaper railway transportation -for the sugar crop. Furthermore, with railway improvements should go the -blessings that agricultural experiments can bestow. A government farm in -a suitable place would establish rice and cotton cultivation. Many of -the playas or lower alluvial lands along the rivers can be irrigated. -Only a small fraction of the water of the Rio Urubamba is now turned out -upon the fields. For a large part of the year the natural rainfall would -suffice to keep rice in good condition. Six tons a year are now grown on -Hacienda Sahuayaco for local use on account of the heavy rate on rice -imported on muleback from Cuzco, whither it comes by sea and by trail -from distant coastal valleys. The lowland people also need rice and it -could be sent to them down river by an easier route than that over which -their supplies now come. It should be exported to the highlands, not -imported therefrom. There are so many varieties adapted to so many kinds -of soil and climate that large amounts should be produced at fair -profits. - -The cotton plant, on the other hand, is more particular about climate -and especially the duration of dry and wet seasons; in spite of this its -requirements are all met in the Santa Ana Valley. The rainfall is -moderate and there is an abundance of dry warm soil. The plant could -make most of its growth in the wet season, and the four months of cooler -dry season with only occasional showers would favor both a bright staple -and a good picking season. More labor would be required for cotton and -rice and for the increased production of cacao than under the present -system. This would not be a real difficulty if the existing labor -supply were conserved by the practical abolition, through heavy -taxation, of the brandy that is the chief cause of the laborer's vicious -habits. This is the first step in securing the best return upon the -capital invested in a railway. Economic progress is here bound up with a -very practical morality. Colonization in the eastern valleys, of which -there have been but a few dismal attempts, will only extend the field of -influence, it will not solve the real problem of bringing the people of -the rich eastern territory of Peru into full and honorable possession of -their natural wealth. - -The value of the eastern valleys was known in Inca times, for their -stone-faced terraces and coca-drying patios may still be seen at -Echarati and on the border of the Chaupimayu Valley at Sahuayaco. -Tradition has it that here were the imperial coca lands, that such of -the forest Indians as were enslaved were obliged to work upon them, and -that the leaves were sent to Cuzco over a paved road now covered with -"montaña" or forest. The Indians still relate that at times a -mysterious, wavering, white light appears on the terraces and hills -where old treasure lies buried. Some of the Indians have gold and silver -objects which they say were dug from the floors of hill caves. There -appears to have been an early occupation of the best lands by the -Spaniards, for the long extensions down them of Quechua population upon -which the conquerors could depend no doubt combined with the special -products of the valley to draw white colonists thither.[12] General -Miller,[13] writing in 1836, mentions the villages of Incharate -(Echarati) and Sant' Ana (Santa Ana) but discourages the idea of -colonization "... since the river ... has lofty mountains on either -side of it, and is not navigable even for boats." - -In the "Itinerario de los viajes de Raimondi en el Peru"[14] there is an -interesting account of the settlement by the Rueda family of the great -estate still held by a Rueda, the wife of Señor Duque. José Rueda, in -1829, was a government deputy representative and took his pay in land, -acquiring valuable territory on which there was nothing more than a -mission. In 1830 Rueda ceded certain lands in "arriendo" (rent) and on -these were founded the haciendas Pucamoco, Sahuayaco, etc. - -Señor Gonzales, the present owner of Hacienda Sahuayaco, recently -obtained his land--a princely estate, ten miles by forty--for 12,000 -soles ($6,000). In a few years he has cleared the best tract, built -several miles of canals, hewed out houses and furniture, planted coca, -cacao, cane, coffee, rice, pepper, and cotton, and would not sell for -$50,000. Moreover, instead of being a superintendent on a neighboring -estate and keeping a shop in Cuzco, where his large family was a source -of great expense, he has become a wealthy landowner. He has educated a -son in the United States. He is importing machinery, such as a rice -thresher and a distilling plant. His son is looking forward to the -purchase of still more playa land down river. He pays a sol a day to -each laborer, securing men from Cotabambas and Abancay, where there are -many Indians, a low standard of wages, little unoccupied land, and a hot -climate, so that the immigrants do not need to become acclimatized. - -The deepest valleys in the Eastern Andes of Peru have a semi-arid -climate which brings in its train a variety of unusual geographic -relations. At first as one descends the valley the shady and sunny -slopes show sharply contrasted vegetation. - -[Illustration: FIG. 51--Robledo's mountain-side trail in the Urubamba -Valley below Rosalina.] - -[Illustration: FIG. 52--An epiphyte partly supported by a dead host at -Rosalina, elevation 2,000 feet. The epiphyte bears a striking -resemblance to a horned beast whose arched back, tightly clasped -fingers, and small eyes give it a peculiarly malignant and life-like -expression.] - -[Illustration: FIG. 53A--The smooth grassy slopes at the junction of the -Yanatili (left) and Urubamba (right) rivers near Pabellon.] - -[Illustration: FIG. 53B--Distribution of vegetation in the Urubamba -Valley near Torontoy. The patches of timber in the background occupy the -shady sides of the spurs; the sunny slopes are grass-covered; the valley -floor is filled with thickets and patches of woodland but not true -forest.] - -The one is forested, the other grass-covered. Slopes that receive the -noon and afternoon sun the greater part of the year are hottest and -therefore driest. For places in 11° south latitude the sun is well to -the north six months of the year, nearly overhead for about two months, -and to the south four months. Northwesterly aspects are therefore driest -and warmest, hence also grass-covered. In many places the line between -grass and forest is developed so sharply that it seems to be the -artificial edge of a cut-over tract. This is true especially if the -relief is steep and the hill or ridge-crests sharp.[15] - -[Illustration: FIG. 54--Climatic cross-section from the crest of the -Cordillera Vilcapampa down the eastern mountain valleys to the tropical -plains.] - -At Santa Ana this feature is developed in an amazingly clear manner, and -it is also combined with the dry timber line and with productivity in a -way I have never seen equaled elsewhere. The diagram will explain the -relation. It will be seen that the front range of the mountains is high -enough to shut off a great deal of rainfall. The lower hills and ridges -just within the front range are relatively dry. The deep valleys are -much drier. Each broad expansion of a deep valley is therefore a dry -pocket. Into it the sun pours even when all the surrounding hills and -mountains are wrapped in cloud. The greater number of hours of sunshine -hastens the rate of evaporation and still further increases the dryness. -Under the spur of much sunlight and of ample irrigation water from the -wetter hill slopes, the dry valley pockets produce huge crops of fruit -and cane. - -The influence of the local climate upon tree growth is striking. Every -few days, even in the relatively dry winter season, clouds gather about -the hills and there are local showers. The lower limit of the zone of -clouds is sharply marked and at both Santa Ana and Echarati it is -strikingly constant in elevation--about five thousand feet above sea -level. From the upper mountains the forest descends, with only small -patches of glade and prairie. At the lower edge of the zone of cloud it -stops abruptly on the warmer and drier slopes that face the afternoon -sun and continues on the moister slopes that face the forenoon sun or -that slope away from the sun. - -But this is not the only response the vegetation makes. The forest -changes in character as well as in distribution. The forest in the wet -zone is dense and the undergrowth luxuriant. In the selective slope -forest below the zone of cloud the undergrowth is commonly thin or -wanting and the trees grow in rather even-aged stands and by species. -Finally, on the valley floor and the tributary fans, there is a distinct -growth of scrub with bands of trees along the water courses. Local -tracts of coarse soil, or less rain on account of a deep "hole" in a -valley surrounded by steeper and higher mountains, or a change in the -valley trend that brings it into less free communication with the -prevailing winds, may still further increase the dryness and bring in a -true xerophytic or drought-resisting vegetation. Cacti are common all -through the Santa Ana Valley and below Sahuayaco there is a patch of -tree cacti and similar forms several square miles in extent. Still -farther down and about half-way between Sahuayaco and Pabellon are -immense tracts of grass-covered mountain slopes (Fig. 53). These extend -beyond Rosalina, the last of them terminating near Abra Tocate (Fig. -15). The sudden interruption is due to a turn in the valley giving -freer access to the up-valley winds that sweep through the pass at Pongo -de Mainique. - -[Illustration: FIG. 55--Map to show the relation of the grasslands of -the dry lower portion of the Urubamba Valley (unshaded) to the forested -lands at higher elevations (shaded). See Fig. 54 for climatic -conditions. Patches and slender tongues of woodland occur below the main -timber line and patches of grassland above it.] - -Northward from Abra Tocate (Fig. 55) the forest is practically -continuous. The break between the two vegetal regions is emphasized by a -corral for cattle and mules, the last outpost of the plateau herdsmen. -Not three miles away, on the opposite forested slope of the valley, is -the first of the Indian clearings where several families of Machigangas -spend the wet season when the lower river is in flood (Fig. 21). The -grass lands will not yield corn and coca because the soil is too thin, -infertile, and dry. The Indian farms are therefore all in the forest and -begin almost at its very edge. Here finally terminates a long peninsula -of grass-covered country. Below this point the heat and humidity rapidly -increase; the rains are heavier and more frequent; the country becomes -almost uninhabitable for stock; transportation rates double. Here is the -undisputed realm of the forest with new kinds of trees and products and -a distinctive type of forest-dwelling Indian. - -At the next low pass is the skull of an Italian who had murdered his -companions and stolen a season's picking of rubber, attempting to escape -by canoe to the lower Urubamba from the Pongo de Mainique. The -Machigangas overtook him in their swiftest dugouts, spent a night with -him, and the next morning shot him in the back and returned with their -rightful property--a harvest of rubber. For more than a decade -foreigners have been coming down from the plateau to exploit them. They -are an independent and free tribe and have simple yet correct ideas of -right and wrong. Their chief, a man of great strength of character and -one of the most likeable men I have known, told me that he placed the -skull in the pass to warn away the whites who came to rob honest -Indians. - -The Santa Ana Valley between the Canyon of Torontoy and the heavy forest -belt below Rosalina is typical of many of the eastern valleys of Peru, -both in its physical setting and in its economic and labor systems. -Westward are the outliers of the Vilcapampa range; on the east are the -smaller ranges that front the tropical lowlands. Steep valleys descend -from the higher country to join the main valley and at the mouth of -every tributary is an alluvial fan. If the alluvium is coarse and -steeply inclined there is only pasture on it or a growth of scrub. If -fine and broad it is cleared and tilled. The sugar plantations begin at -Huadquiña and end at Rosalina. Those of Santa Ana and Echarati are the -most productive. It takes eighteen months for the cane to mature in the -cooler weather at Huadquiña (8,000 feet). Less than a year is required -at Santa Ana (3,400 feet). Patches of alluvium or playas, as they are -locally called, continue as far as Santo Anato, but they are cultivated -only as far as Rosalina. The last large plantation is Pabellon; the -largest of all is Echarati. All are irrigated. In the wet months, -December to March inclusive, there is little or no irrigation. In the -four months of the dry season, June to September inclusive, there is -frequent irrigation. Since the cane matures in about ten months the -harvest seasons fall irregularly with respect to the seasons of rain. -Therefore the land is cleared and planted at irregular intervals and -labor distributed somewhat through the year. There is however a -concentration of labor toward the end of the dry season when most of the -cane is cut for grinding. - -The combined freight rate and government tax on coca, sugar, and brandy -take a large part of all that the planter can get for his crop. It is -120 miles (190 km.) from Santa Ana to Cuzco and it takes five days to -make the journey. The freight rate on coca and sugar for mule carriage, -the only kind to be had, is two cents per pound. The national tax is one -cent per pound (0.45 kg.). The coca sells for twenty cents a pound. The -cost of production is unknown, but the paid labor takes probably -one-half this amount. The planter's time, capital, and profit must come -out of the rest. On brandy there is a national tax of seven cents per -liter (0.26 gallon) and a municipal tax of two and a half cents. It -costs five cents a liter for transport to Cuzco. The total in taxes and -transport is fourteen and a half cents a liter. It sells for twenty -cents a liter. Since brandy (aguardiente), cacao (for chocolate), and -coca leaves (for cocaine) are the only precious substances which the -valleys produce it takes but a moment's inspection to see how onerous -these taxes would be to the planter if labor did not, as usual, pay the -penalty. - -Much of the labor on the plantations is free of cost to the owner and is -done by the so-called _faena_ or free Indians. These are Quechuas who -have built their cabins on the hill lands of the planters, or on the -floors of the smaller valleys. The disposition of their fields in -relation to the valley plantations is full of geographic interest. Each -plantation runs at right angles to the course of the valley. Hacienda -Sahuayaco is ten miles (16 km.) in extent down valley and forty miles -(64 km.) from end to end across the valley, and it is one of the smaller -plantations! It follows that about ten square miles lie on the valley -floor and half of this can ultimately be planted. The remaining three -hundred and ninety square miles include some mountain country with -possible stores of mineral wealth, and a great deal of "fells" -country--grassy slopes, graded though steep, excellent for pasture, with -here and there patches of arable land. But the hill country can be -cultivated only by the small farmer who supplements his supply of food -from cultivated plants like potatoes, corn, and vegetables, by keeping -cattle, mules, pigs, and poultry, and by raising coca and fruit. - -The Indian does not own any of the land he tills. He has the right -merely to live on it and to cultivate it. In return he must work a -certain number of days each year on the owner's plantation. In many -cases a small money payment is also made to the planter. The planter -prefers labor to money, for hands are scarce throughout the whole -eastern valley region. No Indian need work on the planter's land without -receiving pay directly therefor. Each also gets a small weekly allotment -of aguardiente while in the planter's employ. - -The scene every Saturday night outside the office of the _contador_ -(treasurer) of a plantation is a novel one. Several hundred Indians -gather in the dark patio in front of the office. Within the circle of -the feeble candlelight that reaches only the margin of the crowd one may -see a pack of heavy, perspiring faces. Many are pock-marked from -smallpox; here and there an eye is missing; only a few are jovial. A -name is shouted through the open door and an Indian responds. He pulls -off his cap and stands stupid and blinking, while the contador asks: - -"Faena" (free)? - -"Si, Señor," he answers. - -"Un sol" (one "sol" or fifty cents gold). The assistant hands over the -money and the man gives way to the next one on the list. If he is a -laborer in regular and constant employ he receives five soles (two fifty -gold) per week. There are interruptions now and then. A ragged, -half-drunken man has been leaning against the door post, suspiciously -impatient to receive his money. Finally his name is called. - -"Faena?" asks the contador. - -"No, Señor, cinco (five) soles." - -At that the field _superintendente_ glances at his time card and speaks -up in protest. - -"You were the man that failed to show up on Friday and Saturday. You -were drunk. You should receive nothing." - -"No, mi patrón," the man contends, "I had to visit a sick cousin in the -next valley. Oh, he was very sick, Señor," and he coughs harshly as if -he too were on the verge of prostration. The sick cousin, a faena -Indian, has been at work in another cane field on the same plantation -for two days and now calls out that he is present and has never had a -sick day in his life. Those outside laugh uproariously. The contador -throws down two soles and the drunkard is pushed back into the sweating -crowd, jostled right and left, and jeered by all his neighbors as he -slinks away grumbling. - -Another Indian seems strangely shy. He scarcely raises his voice above a -whisper. He too is a faena Indian. The contador finds fault. - -"Why didn't you come last month when I sent for you?" - -The Indian fumbles his cap, shuffles his feet, and changes his coca cud -from one bulging cheek to the other before he can answer. Then huskily: - -"I started, Señor, but my woman overtook me an hour afterward and said -that one of the ewes had dropped a lamb and needed care." - -"But your woman could have tended it!" - -"No, Señor, she is sick." - -"How, then, could she have overtaken you?" he is asked. - -"She ran only a little way and then shouted to me." - -"And what about the rest of the month?" persists the contador. - -"The other lambs came, Señor, and I should have lost them all if I had -left." - -The contador seems at the end of his complaint. The Indian promises to -work overtime. His difficulties seem at an end, but the superintendent -looks at his old record. - -"He always makes the same excuse. Last year he was three weeks late." - -So the poor shepherd is fined a sol and admonished that his lands will -be given to some one else if he does not respond more promptly to his -patron's call for work. He leaves behind him a promise and the rank -mixed smell of coca and much unwashed woolen clothing. - -It is not alone at the work that they grumble. There is malaria in the -lower valleys. Some of them return to their lofty mountain homes -prostrated with the unaccustomed heat and alternately shaking with -chills and burning with fever. Without aid they may die or become so -weakened that tuberculosis carries them off. Only their rugged strength -enables the greater number to return in good health. - -A plantation may be as large as a principality and draw its laborers -from places fifty miles away. Some of the more distant Indians need not -come to work in the canefields. Part of their flock is taken in place of -work. Or they raise horses and mules and bring in a certain number each -year to turn over to the patron. Hacienda Huadquiña (Fig. 46) takes in -all the land from the snow-covered summits of the Cordillera Vilcapampa -to the canefields of the Urubamba. Within the broad domain are half the -climates and occupations characteristic of Peru. It is difficult to see -how a thousand Indians can be held to even a mixed allegiance. It seems -impossible that word can be got to them. However the native "telegraph" -is even more perfect than that among the forest Indians. From one to the -other runs the news that they are needed in the canefields. On the trail -to and from a mountain village, in their ramblings from one high pasture -to another, within the dark walls of their stone and mud huts when they -gather for a feast or to exchange drinks of brandy and _chicha_--the -word is passed that has come up from the valleys. - -For every hundred faena Indians there are five or six regular laborers -on the plantations, so with the short term passed by the faena Indians -their number is generally half that of the total laborers at work at any -one time. They live in huts provided for them by the planter, and in the -houses of their friends among the regular laborers. Here there are -almost nightly carousals. The regular laborer comes from the city or the -valley town. The faena laborer is a small hill farmer or shepherd. They -have much to exchange in the way of clothing, food, and news. I have -frequently had their conversations interpreted for me. They ask about -the flocks and the children, who passed along the trails, what accidents -befell the people. - -"Last year," droned one to another over their chicha, "last year we lost -three lambs in a hailstorm up in the high fields near the snow. It was -very cold. My foot cracked open and, though I have bound it with wet -coca leaves every night, it will not cure," and he displays his heel, -the skin of which is like horn for hardness and covered with a crust of -dirt whose layers are a record of the weather and of the pools he has -waded for years. - -Their wanderings are the main basis of conversation. They know the -mountains better than the condors do. We hired a small boy of twelve at -Puquiura. He was to build our fires, carry water, and help drive the -mules. He crossed the Cordillera Vilcapampa on foot with us. He -scrambled down into the Apurimac canyon and up the ten thousand feet of -ascent on the other side, twisted the tails of the mules, and shouted -more vigorously then the arrieros. He was engaged to go with us to -Pasaje, where his father would return with him in a month. But he -climbed to Huascatay with us and said he wanted to see Abancay. When an -Indian whom we pressed into service dropped the instruments on the trail -and fled into the brush the boy packed them like a man. The soldier -carried a tripod on his back. The boy, not to be outdone, insisted on -carrying the plane table, and to his delight we called him a soldier -too. He went with us to Huancarama. When I paid him he smiled at the -large silver soles that I put into his hand; and when I doubled the -amount for his willingness to work his joy was unbounded. Forthwith he -set out, this time on muleback, on the return journey. The last I saw of -him he was holding his precious soles in a handkerchief and kicking his -beast with his bare heels, as light-hearted as a cavalier. Often I find -myself wondering whether he returned safely with his money. I should -very much like to see him again, for with him I associate cheerfulness -in difficult places and many a pleasant camp-fire. - - - - -CHAPTER VII - -THE GEOGRAPHIC BASIS OF REVOLUTIONS AND OF HUMAN CHARACTER IN THE -PERUVIAN ANDES - - -Human character as a spontaneous development has always been a great -factor in shaping historical events, but it is a striking fact that in -the world of our day its influence is exerted chiefly in the lowest and -highest types of humanity. The savage with his fetishes, his taboos, and -his inherent childlikeness and suspicion needs only whim or a slight -religious pretext to change his conduct. Likewise the really educated -and the thoughtful act from motives often wholly unrelated to economic -conditions or results. But the masses are deeply influenced by whatever -affects their material welfare. A purely idealistic impulse may -influence a people, but in time its effects are always displayed against -an economic background. - -There is a way whereby we may test this theory. In most places in the -world we have history in the making, and through field studies we can -get an intimate view of it. It is peculiarly the province of geography -to study the present distribution and character of men in relation to -their surroundings and these are the facts of mankind that must forever -be the chief data of economic history. It is not vain repetition to say -that this means, first of all, the study of the character of men in the -fullest sense. It means, in the second place, that a large part of the -character must be really understood. Whenever this is done there is -found a geographic basis of human character that is capable of the -clearest demonstration. It is in the geographic environment that the -material motives of humanity have struck their deepest roots. - -These conclusions might be illustrated from a hundred places in the -field of study covered in this book. Almost every chapter of Part I -contains facts of this character. I wish, however, to discuss the -subject specifically and for that purpose now turn to the conditions of -life in the remoter mountain valleys and to one or two aspects of the -revolutions that occur now and then in Peru. The last one terminated -only a few months before our arrival and it was a comparatively easy -matter to study both causes and effects. - -A caution is necessary however. It is a pity that we use the term -"revolution" to designate these little disturbances. They affect -sometimes a few, again a few hundred men. Rarely do they involve the -whole country. A good many of them are on a scale much smaller than our -big strikes. Most of them involve a loss of life smaller than that which -accompanies a city riot. They are in a sense strikes against the -government, marked by local disorders and a little violence. - -Early in 1911 the Prefect of the Department of Abancay had crowned his -long career by suppressing a revolution. He had been Subprefect at -Andahuaylas, and when the rebels got control of the city of Abancay and -destroyed some of the bridges on the principal trails, he promptly -organized a military expedition, constructed rafts, floated his small -force of men across the streams, and besieged the city. The rebel force -was driven at last to take shelter in the city jail opposite the -Prefectura. There, after the loss of half their number, they finally -surrendered. Seventy-five of them were sent to the government -penitentiary at Arequipa. Among the killed were sons from nearly half -the best families of Abancay. All of the rebels were young men. - -It would be difficult to give an adequate idea of the hatred felt by the -townspeople toward the government. Every precaution was taken to prevent -a renewal of the outbreak. Our coming was telegraphed ahead by -government agents who looked with suspicion upon a party of men, well -armed and provisioned, coming up from the Pasaje crossing of the -Apurimac, three days' journey north. The deep canyon affords shelter not -only to game, but also to fugitives, rebels, and bandits. The government -generally abandons pursuit on the upper edge of the canyon, for only a -prolonged guerilla warfare could completely subdue an armed force -scattered along its rugged walls and narrow floor. The owner of the -hacienda at Pasaje is required to keep a record of all passengers rafted -across the Apurimac, but he explains significantly that some who pass -are too hurried to write their names in his book. Once he reaches the -eastern wall of the canyon a fugitive may command a view of the entire -western wall and note the approach of pursuers. Thence eastward he has -the whole Cordillera Vilcapampa in which to hide. Pursuit is out of the -question. - -When we arrived, the venerable Prefect, a model of old-fashioned -courtesy, greeted us with the utmost cordiality. He told us of our -movements since leaving Pasaje, and laughingly explained that since we -had sent him no friendly message and had come from a rebel retreat, he -had taken it for granted that we intended to storm the town. I assured -him that we were ready to join his troops, if necessary, whereupon, with -a delightful frankness, he explained his method of keeping the situation -in hand. Several troops of cavalry and two battalions of infantry were -quartered at the government barracks. Every evening the old gentleman, a -Colonel in the Peruvian army, mounted a powerful gray horse and rode, -quite unattended, through the principal streets of the town. Several -times I walked on foot behind him, again I preceded him, stopping in -shops on the way to make trivial purchases, to find out what the people -had to say about him and the government as he rode by. One old gentleman -interested me particularly. He had only the day before called at the -Prefectura to pay his respects. Although his manner was correct there -was lacking to a noticeable degree the profusion of sentiment that is -apt to be exhibited on such an occasion. He now sat on a bench in a -shop. Both his own son and the shopkeeper's son had been slain in the -revolution. It was natural that they should be bitter. But the precise -nature of their complaint was what interested me most. One said that he -did not object to having his son lose his life for his country. But that -his country's officials should hire Indians to shoot his son seemed to -him sheer murder. Later, at Lambrama, I talked with a rebel fugitive, -and that was also his complaint. The young men drafted into the army are -Indians, or mixed, never whites. White men, and men with a small -amount of Indian blood, officer the army. When a revolutionary party -organizes it is of course made up wholly of men of white and mixed -blood, never Indians. The Indians have no more grievance against one -white party than another. Both exploit him to the limit of law and -beyond the limit of decency. He fights if he must, but never by choice. - -[Illustration: FIG. 56--The type of forest in the moister tracts of the -valley floor at Sahuayaco. In the center of the photograph is a tree -known as the "sandy matico" used in making canoes for river navigation.] - -[Illustration: FIG. 57--Arboreal cacti in the mixed forest of the dry -valley floor below Sahuayaco.] - -[Illustration: FIG. 58--Crossing the Apurimac at Pasaje. These are -mountain horses, small and wiry, with a protective coat of long hair. -They are accustomed to graze in the open without shelter during the -entire winter.] - -[Illustration: FIG. 59--Crossing the Apurimac at Pasaje. The mules are -blindfolded and pushed off the steep bank into the water and rafted -across.] - -Thus Indian troops killed the white rebels of Abancay. - -"Tell me, Señor," said the fugitive, "if you think that just. Tell me -how many Indians you think a white man worth. Would a hundred dead -Indians matter? But how replace a white man where there are so few? The -government _assassinated_ my compatriots!" - -"But," I replied, "why did you fight the government? All of you were -prosperous. Your fathers may have had a grievance against the -government, but of what had you young men to complain?" - -His reply was far from convincing. He was at first serious, but his long -abstract statements about taxes and government wastefulness trailed off -into vagueness, and he ended in a laughing mood, talking about -adventure, the restless spirit of young men, and the rich booty of -confiscated lands and property had the rebels won. He admitted that it -was a reckless game, but when I called him a mere soldier of fortune he -grew serious once more and reverted to the iniquitous taxation system of -Peru. Further inquiry made it quite clear that the ill-fated revolution -of Abancay was largely the work of idle young men looking for adventure. -It seemed a pity that their splendid physical energy could not have been -turned into useful channels. The land sorely needs engineers, -progressive ranchmen and farmers, upright officials, and a spirit of -respect for law and order. Old men talked of the unstable character of -the young men of the time, but almost all of them had themselves been -active participants in more than one revolution of earlier years. - -Every night at dinner the Prefect sent off by government telegraph a -long message to the President of the Republic on the state of the -Department, and received similar messages from the central government -about neighboring departments. These he read to us, and, curiously -enough, to the entire party, made up of army officers and townsmen. I -was surprised to find later that the company included one government -official whose son had been among the imprisoned rebels at Arequipa. We -met the young man a week later at a mountain village, a day after a -general amnesty had been declared. His escape had been made from the -prison a month before. He forcibly substituted the mess-boy's clothing -for his own, and thus passed out unnoticed. After a few days' hiding in -the city, he set out alone across the desert of Vitor, thence across the -lofty volcanic country of the Maritime Andes, through some of the most -deserted, inhospitable land in Peru, and at the end of three weeks had -reached Lambrama, near Abancay, the picture of health! - -Later I came to have a better notion of the economic basis of the -revolution, for obviously the planters and the reckless young men must -have had a mutual understanding. Somewhere the rebels had obtained the -sinews of war. The planters did not take an open part in the revolution, -but they financed it. When the rebels were crushed, the planters, at -least outwardly, welcomed the government forces. Inwardly they cursed -them for thwarting their scheme. The reasons have an interesting -geographic basis. Abancay is the center of a sugar region. Great -irrigated estates are spread out along the valley floor and the enormous -alluvial fans built into the main valley at the mouths of the tributary -streams. There is a heavy tax on sugar and on aguardiente (brandy) -manufactured from cane juice. The _hacendados_ had dreamed of lighter -taxes. The rebels offered the means of securing relief. But taxes were -not the real reason for the unrest, for many other sugar producers pay -the tax without serious complaint. Abancay is cut off from the rest of -Peru by great mountains. Toward the west, _via_ Antabamba, Cotahuasi, -and Chuquibamba, two hundred miles of trail separate its plantations -from the Pacific. Twelve days' hard riding is required to reach Lima -over the old colonial trade route. It is three days to Cuzco at the end -of the three-hundred-mile railway from the port of Mollendo. The trails -to the Atlantic rivers are impossible for trading purposes. Deep sunk in -a subtropical valley, the irrigable alluvial land of Abancay tempts the -production of sugar. - -But nature offers no easy route out of the valley. For centuries the -product has been exported at almost prohibitive cost, as in the eastern -valley of Santa Ana. The coastal valleys enjoy easy access to the sea. -Each has its own port at the valley mouth, where ocean steamers call for -cargo. Many have short railway lines from port to valley head. The -eastern valleys and Abancay have been clamoring for railways, better -trails, and wagon roads. From the public fund they get what is left. The -realization of their hopes has been delayed too long. It would be both -economic and military strategy to give them the desired railway. -Revolutions in Peru always start in one of two ways: either by a _coup_ -at Lima or an unchecked uprising in an interior province. Bolivia has -shown the way out of this difficulty. Two of her four large centers--La -Paz and Oruro--are connected by rail, and the line to Cochabamba lacks -only a few kilometres of construction.[16] To Sucre a line has been long -projected. Formerly a revolution at one of the four towns was -exceedingly difficult to stamp out. Diaz had the same double motive in -encouraging railway building in the remote desert provinces of Northern -Mexico, where nine out of ten Mexican revolutions gather headway. -Argentina has enjoyed a high degree of political unity since her railway -system was extended to Córdoba and Tucumán. The last uprising, that of -1906, took place on her remotest northeastern frontier. - -We had ample opportunity to see the hatred of the rebels. At nightfall -of September 25th we rode into the courtyard of Hacienda Auquibamba. We -had traveled under the worst possible circumstances. Our mules had been -enfeebled by hot valley work at Santa Ana and the lower Urubamba and the -cold mountain climate of the Cordillera Vilcapampa. The climb out of the -Apurimac canyon, even without packs, left them completely exhausted. We -were obliged to abandon one and actually to pull another along. It had -been a hard day in spite of a prolonged noon rest. Everywhere our -letters of introduction had won an outpouring of hospitality among a -people to whom hospitality is one of the strongest of the unwritten laws -of society. Our soldier escort rode ahead of the pack train. - -As the clatter of his mules' hoofs echoed through the dark buildings the -manager rushed out, struck a light and demanded "Who's there?" To the -soldier's cheerful "Buena noche, Señor," he sneeringly replied "Halto! -Guardia de la República, aqui hay nada para un soldado del gobierno." -Whereupon the soldier turned back to me and said we should not be able -to stop here, and coming nearer me he whispered "He is a revolutionary." -I dismounted and approached the haughty manager, who was in a really -terrible mood. Almost before I could begin to ask him for accommodations -he rattled off that there was no pasture for our beasts, no food for us, -and that we had better go on to the next hacienda. "Absolutamente nada!" -he repeated over and over again, and at first I thought him drunk. Since -it was then quite dark, with no moon, but instead heavy black clouds -over the southern half of the sky and a brisk valley wind threatening -rain, I mildly protested that we needed nothing more than shelter. Our -food boxes would supply our wants, and our mules, even without fodder, -could reach Abancay the next day. Still he stormed at the government and -would have none of us. I reminded him that his fields were filled with -sugar cane and that it was the staple forage for beasts during the part -of the year when pasture was scarce. The cane was too valuable, he said. -It was impossible to supply us. I was on the point of pitching camp -beside the trail, for it was impossible to reach the next hacienda with -an exhausted outfit. - -Just then an older man stepped into the circle of light and amiably -inquired the purpose of our journey. When it was explained, he turned to -the other and said it was unthinkable that men should be treated so -inhospitably in a strange land. Though he himself was a guest he urged -that the host should remember the laws of hospitality, whereupon the -latter at last grudgingly asked us to join him at his table and to turn -our beasts over to his servants. It was an hour or more before he would -exhibit any interest in us. When he had learned of our object in -visiting Abancay he became somewhat more friendly, though his hostility -still manifested itself. Nowhere else in South America have I seen -exhibited such boorish conduct. Nevertheless the next morning I noticed -that our mules had been well fed. He said good-by to us as if he were -glad to be rid of any one in any way connected with the hostile -government. Likewise the manager at Hacienda Pasaje held out almost -until the last before he would consent to aid us with fresh beasts. -Finally, after a day of courting I gave him a camp chair. He was so -pleased that he not only gave us beasts, but also a letter of -introduction to one of his caretakers on a farm at the top of the -cuesta. Here on a cold, stormy night we found food and fuel and the -shelter of a friendly roof. - -A by-product of the revolution, as of all revolutions in thinly settled -frontier regions, was the organization of small bands of outlaws who -infested the lonely trails, stole beasts, and left their owners robbed -and helpless far from settlements. We were cautioned to beware of them, -both by Señor Gonzales, the Prefect at Abancay, and by the Subprefect of -Antabamba. Since some of the bandits had been jailed, I could not doubt -the accuracy of the reports, but I did doubt stories of murder and of -raids by large companies of mountain bandits. As a matter of fact we -were robbed by the Governor of Antabamba, but in a way that did not -enable us to find redress in either law or lead. The story is worth -telling because it illustrates two important facts: first, the vile -so-called government that exists in some places in the really remote -sections of South America, and second, the character of the mountain -Indians. - -The urgent letter from the Prefect of Abancay to the Subprefect of -Antabamba quickly brought the latter from his distant home. When we -arrived we found him drinking with the Governor. The Subprefect was most -courteous. The Governor was good-natured, but his face exhibited a rare -combination of cruelty and vice. We were offered quarters in the -municipal building for the day or two that we were obliged to stop in -the town. The delay enabled us to study the valley to which particular -interest attaches because of its situation in the mountain zone between -the lofty pastures of the Alpine country and the irrigated fields of the -valley farmers. - -Antabamba itself lies on a smooth, high-level shoulder of the youthful -Antabamba Valley. The valley floor is narrow and rocky, and affords -little cultivable land. On the valley sides are steep descents and -narrow benches, chiefly structural in origin, over which there is -scattered a growth of scrub, sufficient to screen the deer and the bear, -and, more rarely, vagrant bands of vicuña that stray down from their -accustomed haunts in the lofty Cordillera. Three thousand feet above the -valley floor a broad shoulder begins (Fig. 60) and slopes gently up to -the bases of the true mountains that surmount the broad rolling summit -platform. Here are the great pasture lands of the Andes and their -semi-nomadic shepherds. The highest habitation in the world is located -here at 17,100 feet (5,210 m.), near a secondary pass only a few miles -from the main axis of the western chain, and but 300 feet (91 m.) below -it. - -The people of Antabamba are both shepherds and farmers. The elevation is -12,000 feet (3,658 m.), too high and exposed for anything more than -potatoes. Here is an Indian population pure-blooded, and in other -respects, too, but little altered from its original condition. There is -almost no communication with the outside world. A deep canyon fronts the -town and a lofty mountain range forms the background. - -At nightfall, one after another, the Indians came in from the field and -doffed their caps as they passed our door. Finally came the "Teniente -Gobernador," or Lieutenant Governor. He had only a slight strain of -white blood. His bearing was that of a sneak, and he confirmed this -impression by his frank disdain for his full-blooded townsmen. "How -ragged and ugly they are! You people must find them very stupid," etc. -When he found that we had little interest in his remarks, he asked us if -we had ever seen Lima. We replied that we had, whereupon he said, "Do -you see the gilded cross above the church yonder? I brought that on -muleback all the way from Lima! Think of it! These ignorant people have -never seen Lima!" His whole manner as he drew himself up and hit his -breast was intended to make us think that he was vastly superior to his -neighbors. The sequel shows that our first estimate of him was correct. - -We made our arrangements with the Governor and departed. To inspire -confidence, and at the Governor's urgent request, we had paid in advance -for our four Indians and our fresh beasts--and at double the usual -rates, for it was still winter in the Cordillera. They were to stay with -us until we reached Cotahuasi, in the next Department beyond the -continental divide, where a fresh outfit could be secured. The -Lieutenant Governor accompanied us to keep the party together. They -appeared to need it. Like our Indian peons at Lambrama the week before, -these had been taken from the village jail and represented the scum of -the town. As usual they behaved well the first day. On the second night -we reached the Alpine country where the vegetation is very scanty and -camped at the only spot that offered fuel and water. The elevation was -16,000, and here we had the lowest temperature of the whole journey, +6° -F. (-14.4° C.). Ice covered the brook near camp as soon as the sun went -down and all night long the wind blew down from the lofty Cordillera -above us, bringing flurries of snow and tormenting our unprotected -beasts. It seemed to me doubtful if our Indians would remain. I -discussed with the other members of the party the desirability of -chaining the peons to the tent pole, but this appeared so extreme a -measure that we abandoned the idea after warning the Teniente that he -must not let them escape. - -At daybreak I was alarmed at the unusual stillness about camp. A glance -showed that half our hobbled beasts had drifted back toward Antabamba -and no doubt were now miles away. The four Indian peons had left also, -and their tracks, half buried by the last snowfall, showed that they had -left hours before and that it was useless to try to overtake them. -Furthermore we were making a topographic map across the Cordillera, and, -in view of the likelihood of snow blockading the 17,600-foot (5,360 m.) -pass which we had to cross, the work ought not to be delayed. With all -these disturbing conditions to meet, and suffering acutely from mountain -sickness, I could scarcely be expected to deal gently with our official. -I drew out the sleeping Teniente and set him on his feet. To my inquiry -as to the whereabouts of the Indians that he had promised to guard, he -blinked uncertainly, and after a stupid "Quien sabe?" peered under the -cover of a sheepskin near by as if the peons had been transformed into -insects and had taken refuge under a blade of grass. I ordered him to -get breakfast and after that to take upon his back the instruments that -two men had carried up to that time, and accompany the topographer. Thus -loaded, the Lieutenant Governor of Antabamba set out on foot a little -ahead of the party. Hendriksen, the topographer, directed him to a -17,000-foot peak near camp, one of the highest stations occupied in the -traverse. When the topographer reached the summit the instruments were -there but the Teniente had fled. Hendriksen rapidly followed the tracks -down over the steep snow-covered wall of a deeply recessed cirque, but -after a half-hour's search could not get sight of the runaway, whereupon -he returned to his station and took his observations, reaching camp in -the early afternoon. - -In the meantime I had intercepted two Indians who had come from -Cotahuasi driving a llama train loaded with corn. They held a long -conversation at the top of the pass above camp and at first edged -suspiciously away. But the rough ground turned them back into the trail -and at last they came timidly along. They pretended not to understand -Spanish and protested vigorously that they had to keep on with their -llamas. I thought from the belligerent attitude of the older, which grew -rapidly more threatening as he saw that I was alone, that I was in for -trouble, but when I drew my revolver he quickly obeyed the order to sit -down to breakfast, which consisted of soup, meat, and army biscuits. I -also gave them coca and cigarettes, the two most desirable gifts one can -make to a plateau Indian, and thereupon I thought I had gained their -friendship, for they at last talked with me in broken Spanish. The older -one now explained that he must at all hazards reach Matará by nightfall, -but he would be glad to leave his son to help us. I agreed, and he set -out forthwith. The _arriero_ (muleteer) had now returned with the lost -mules and with the assistance of the Indian we soon struck camp and -loaded our mules. I cautioned the arriero to keep close watch of the -Indian, for at one time I had caught on his face an expression of hatred -more intense than I had ever seen before. The plateau Indian of South -America is usually so stupid and docile that the unexpectedly venomous -look of the man after our friendly conversation and my good treatment -alarmed me. At the last moment, and when our backs were turned, our -Indian, under the screen of the packs, slipped away from us. The arriero -called out to know where he had gone. It took us but a few moments to -gain the top of a hill that commanded the valley. Fully a half-mile away -and almost indistinguishable against the brown of the valley floor was -our late assistant, running like a deer. No mule could follow over that -broken ground at an elevation of 16,000 feet, and so he escaped. - -Fortunately that afternoon we passed a half-grown boy riding back toward -Antabamba and he promised to hand the Governor a note in Spanish, -penciled on a leaf of my traverse book. I dropped all the polite phrases -that are usually employed and wrote as follows: - - -"Señor Gobernador: - - "Your Indians have escaped, likewise the Lieutenant Governor. They - have taken two beasts. In the name of the Prefect of Abancay, I ask - you immediately to bring a fresh supply of men and animals. We - shall encamp near the first pass, three days west of Antabamba, - until you come." - -We were now without Indians to carry the instruments, which had -therefore to be strapped to the mules. Without guides we started -westward along the trail. At the next pass the topographer rode to the -summit of a bluff and asked which of the two trails I intended to -follow. Just then a solitary Indian passed and I shouted back that I -would engage the Indian and precede the party, and he could tell from my -course at the fork of the trail how to direct his map and where to gain -camp at nightfall. But the Indian refused to go with us. All my -threatening was useless and I had to force myself to beat him into -submission with my quirt. Several repetitions on the way, when he -stubbornly refused to go further, kept our guide with us until we -reached a camp site. I had offered him a week's pay for two hours' work, -and had put coca and cigarettes into his hands. When these failed I had -to resort to force. Now that he was about to leave I gave him double the -amount I had promised him. He could scarcely believe his eyes. He rushed -up to the side of my mule, and reaching around my waist embraced me and -thanked me again and again. The plateau Indian is so often waylaid in -the mountains and impressed for service, then turned loose without pay -or actually robbed, that a _promise_ to pay holds no attraction for him. -I had up to the last moment resembled this class of white. He was -astonished to find that I really meant to pay him well. - -Then he set out upon the return, faithfully delivering my note to the -topographer about the course of the trail and the position of the camp. -He had twelve miles to go to the first mountain hut, so that he could -not have traveled less than that distance to reach shelter. The next -morning a mantle of snow covered everything, yet when I pushed back the -tent flap there stood my scantily clad Indian of the night before, -shivering, with sandaled feet in the snow, saying that he had come back -to work for me! - -This camp was number thirteen out of Abancay, and here our topographer -was laid up for three days. Heretofore the elevation had had no effect -upon him, but the excessively lofty stations of the past few days and -the hard climbing had finally prostrated him. We had decided to carry -him out by the fourth day if he felt no better, but happily he recovered -sufficiently to continue the work. The delay enabled the Governor to -overtake us with a fresh outfit. On the morning of our third day in -camp he overtook us with a small escort of soldiers accompanied by the -fugitive Teniente. He said that he had come to arrest me on the charge -of maltreating an official of Peru. A few packages of cigarettes and a -handful of raisins and biscuits so stirred his gratitude that we parted -the best of friends. Moreover he provided us with four fresh beasts and -four new men, and thus equipped we set out for a rendezvous about ten -miles away. But the faithless Governor turned off the trail and sought -shelter at the huts of a company of mountain shepherds. That night his -men slept on the ground in a bitter wind just outside our camp at 17,200 -feet. They complained that they had no food. The Governor had promised -to join us with llama meat for the peons. We fed them that night and -also the next day. But we had by that time passed the crest of the -western Cordillera and were outside the province of Antabamba. The next -morning not only our four men but also our four beasts were missing. We -were stranded and sick just under the pass. To add to our distress the -surgeon, Dr. Erving, was obliged to leave us for the return home, taking -the best saddle animal and the strongest pack mule. It was impossible to -go on with the map. That morning I rode alone up a side valley until I -reached a shepherd's hut, where I could find only a broken-down, -shuffling old mule, perfectly useless for our hard work. - -Then there happened a piece of good luck that seems almost providential. -A young man came down the trail with three pack mules loaded with llama -meat. He had come from the Cotahuasi Valley the week before and knew the -trail. I persuaded him to let us hire one of his mules. In this way and -by leaving the instruments and part of our gear in the care of two -Indian youths we managed to get to Cotahuasi for rest and a new outfit. - -The young men who took charge of part of our outfit interested me very -greatly. I had never seen elsewhere so independent and clear-eyed a pair -of mountain Indians. At first they would have nothing to do with us. -They refused us permission to store our goods in their hut. To them we -were railroad engineers. They said that the railway might come and when -it did it would depopulate the country. The railway was a curse. -Natives were obliged to work for the company without pay. Their uncle -had told them of frightful abuses over at Cuzco and had warned them not -to help the railway people in any way. They had moved out here in a -remote part of the mountains so that white men could not exploit them. - -In the end, however, we got them to understand the nature of our work. -Gifts of various sorts won their friendship, and they consented to guard -the boxes we had to leave behind. Two weeks later, on his return, the -topographer found everything unmolested. - -I could not but feel that the spirit of those strong and independent -young men was much better for Peru than the cringing, subservient spirit -of most of the Indians that are serfs of the whites. The policy of the -whites has been to suppress and exploit the natives, to abuse them, and -to break their spirit. They say that it keeps down revolution; it keeps -the Indian in his place. But certainly in other respects it is bad for -the Indian and it is worse for the whites. Their brutality toward the -natives is incredible. It is not so much the white himself as the -vicious half-breed who is often allied with him as his agent. - -I shall never forget the terror of two young girls driving a donkey -before them when they came suddenly face to face with our party, and we -at the same time hastily scrambled off our beasts to get a photograph of -a magnificent view disclosed at the bend of the steep trail. They -thought we had dismounted to attack them, and fled screaming in abject -fear up the mountain side, abandoning the donkey and the pack of -potatoes which must have represented a large part of the season's -product. It is a kind of highway robbery condoned because it is only -robbing an Indian. He is considered to be lawful prey. His complaint -goes unnoticed. In the past a revolution has offered him sporadic -chances to wreak vengeance. More often it adds to his troubles by -scattering through the mountain valleys the desperate refugees or -lawless bands of marauders who kill the flocks of the mountain shepherds -and despoil their women. - -There are still considerable numbers of Indians who shun the white man -and live in the most remote corners of the mountains. I have now and -again come upon the most isolated huts, invisible from the valley -trails. They were thatched with grass; the walls were of stone; the -rafters though light must have required prodigious toil, for all timber -stops at 12,000 feet on the mountain borders. The shy fugitive who -perches his hut near the lip of a hanging valley far above the trail may -look down himself unseen as an eagle from its nest. When the owner -leaves on a journey, or to take his flock to new pastures, he buries his -pottery or hides it in almost inaccessible caves. He locks the door or -bars it, thankful if the spoiler spares rafters and thatch. - -At length we reached Cotahuasi, a town sprawled out on a terrace just -above the floor of a deep canyon (Fig. 29). Its flower gardens and -pastures are watered by a multitude of branching canals lined with low -willows. Its bright fields stretch up the lower slopes and alluvial fans -of the canyon to the limits of irrigation where the desert begins. The -fame of this charming oasis is widespread. The people of Antabamba and -Lambrama and even the officials of Abancay spoke of Cotahuasi as -practically the end of our journey. Fruits ripen and flowers blossom -every month of the year. Where we first reached the canyon floor near -Huaynacotas, elevation 11,500 feet (3,500 m.), there seemed to be acres -of rose bushes. Only the day before at an elevation of 16,800 feet -(5,120 m.) we had broken thick ice out of a mountain spring in order to -get water; now we were wading a shallow river, and grateful for the -shade along its banks. Thus we came to the town prepared to find the -people far above their plateau neighbors in character. Yet, in spite of -friendly priests and officials and courteous shopkeepers, there was a -spirit strangely out of harmony with the pleasant landscape. - -Inquiries showed that even here, where it seemed that only sylvan peace -should reign, there had recently been let loose the spirit of barbarism. -We shall turn to some of its manifestations and look at the reasons -therefor. - -In the revolution of 1911 a mob of drunken, riotous citizens gathered to -storm the Cotahuasi barracks and the jail. A full-blooded Indian -soldier, on duty at the entrance, ordered the rioters to stop and when -they paid no heed he shot the leader and scattered the crowd. The -captain thereupon ordered the soldier to Arequipa because his life was -no longer safe outside the barracks. A few months later he was assigned -to Professor Bingham's Coropuna expedition. Professor Bingham reached -the Cotahuasi Valley as I was about to leave it for the coast, and the -soldier was turned over to me so that he might leave Cotahuasi at the -earliest possible moment, for his enemies were plotting to kill him. - -He did not sleep at all the last night of his stay and had us called at -three in the morning. He told his friends that he was going to leave -with us, but that they were to announce his leaving a day later. In -addition, the Subprefect was to accompany us until daybreak so that no -harm might befall me while under the protection of a soldier who -expected to be shot from ambush. - -At four o'clock our whispered arrangements were made, we opened the -gates noiselessly, and our small cavalcade hurried through the -pitch-black streets of the town. The soldier rode ahead, his rifle -across his saddle, and directly behind him rode the Subprefect and -myself. The pack mules were in the rear. We had almost reached the end -of the street when a door opened suddenly and a shower of sparks flew -out ahead of us. Instantly the soldier struck spurs into his mule and -turned into a side street. The Subprefect drew his horse back savagely -and when the next shower of sparks flew out pushed me against the wall -and whispered: "Por Dios, quien es?" Then suddenly he shouted: "Sopla no -mas, sopla no mas" (stop blowing). - -Thereupon a shabby penitent man came to the door holding in his hand a -large tailor's flatiron. The base of it was filled with glowing charcoal -and he was about to start his day's work. The sparks were made in the -process of blowing through the iron to start the smoldering coals. We -greeted him with more than ordinary friendliness and passed on. - -At daybreak we had reached the steep western wall of the canyon where -the real ascent begins, and here the Subprefect turned back with many -_felicidades_ for the journey and threats for the soldier if he did not -look carefully after the pack train. From every angle of the zigzag -trail that climbs the "cuesta" the soldier scanned the valley road and -the trail below him. He was anxious lest news of his escape reach his -enemies who had vowed to take his life. Half the day he rode turned in -his saddle so as to see every traveler long before he was within harm's -reach. By nightfall we safely reached Salamanca, fifty miles away (Fig. -62). - -The alertness of the soldier was unusual and I quite enjoyed his close -attention to the beasts and his total abstinence, for an alert and sober -soldier on detail is a rare phenomenon in the interior of Peru. But all -Salamanca was drunk when we arrived--Governor, alcaldes, citizens. Even -the peons drank up in brandy the money that we gave them for forage and -let the beasts starve. The only sober person I saw was the white -telegraph operator from Lima. He said that he had to stay sober, for the -telegraph office--the outward sign of government--was the special object -of attack of every drink-crazed gang of rioters. They had tried to break -in a few nights before and he had fired his revolver point-blank through -the door. The town offered no shelter but the dark filthy hut of the -Gobernador and the tiny telegraph office. So I made up my bed beside -that of the operator. We shared our meals and chatted until a late hour, -he recounting the glories of Lima, to which he hoped to return at the -earliest possible moment, and cursing the squalid town of Salamanca. His -operator's keys were old, the batteries feeble, and he was in continual -anxiety lest a message could not be received. In the night he sprang out -of bed shouting frantically: - -"Estan llamando" (they are calling), only to stumble over my bed and -awaken himself and offer apologies for walking in his sleep. - -Meanwhile my soldier, having regained his courage, began drinking. It -was with great difficulty that I got started, after a day's delay, on -the trail to Chuquibamba. There his thirst quite overcame him. To -separate him from temptation it became necessary to lock him up in the -village jail. This I did repeatedly on the way to Mollendo, except -beyond Quilca, where we slept in the hot marshy valley out of reach of -drink, and where the mosquitoes kept us so busy that either eating or -drinking was almost out of the question. - -The drunken rioters of Cotahuasi and their debauched brothers at -Salamanca are chiefly natives of pure or nearly pure Indian blood. They -are a part of the great plateau population of the Peruvian Andes. Have -they degenerated to their present low state, or do they display merely -the normal condition of the plateau people? Why are they so troublesome -an element? To this as to so many questions that arise concerning the -highland population we find our answer not chiefly in government, or -religion, or inherited character, but in geography. I doubt very much if -a greater relative difference would be seen if two groups of whites were -set down, the one in the cold terrace lands of Salamanca, the other in -the warm vineyards of Aplao, in the Majes Valley. The common people of -these two towns were originally of the same race, but the lower valley -now has a white element including even most of those having the rank of -peons. Greater differences in character could scarcely be found between -the Aztecs and the Iroquois. In the warm valley there is of coarse -drunkenness, but it is far from general; there is stupidity, but the -people are as a whole alert; and finally, the climate and soil produce -grapes from which famous wines are made, they produce sugar cane, -cotton, and alfalfa, so that the whites have come in, diluted the Indian -blood, and raised the standard of life and behavior. Undoubtedly their -influence would tend to have the same general effect if they mixed in -equal numbers with the plateau groups. There is, however, a good reason -for their not doing so. - -[Illustration: FIG. 62--Salamanca, on the floor of the deep Arma Valley -(a tributary of one of the major coast valleys, the Ocoña), which is -really a canyon above this point and which, in spite of its steepness, -is thoroughly terraced and intensively cultivated up to the frost line.] - -[Illustration: FIG. 60--View across the Antabamba canyon just above -Huadquirca.] - -[Illustration: FIG. 61--Huancarama, west of Abancay, on the famous Lima -to Buenos Aires road. Note the smooth slopes in the foreground. See -Chapter XI.] - -The lofty towns of the plateau have a really wretched climate. White men -cannot live comfortably at Antabamba and Salamanca. Further, they are so -isolated that the modest comforts and the smallest luxuries of -civilization are very expensive. To pay for them requires a profitable -industry managed on a large scale and there is no such industry in the -higher valleys. The white who goes there must be satisfied to live like -an Indian. The result is easy to forecast. Outside of government -officers, only the dissolute or unsuccessful whites live in the worst -towns, like Salamanca and Antabamba. A larger valley with a slightly -milder climate and more accessible situation, like Chuquibamba, will -draw a still better grade of white citizen and in the largest of -all--Cuzco and the Titicaca basin--we find normal whites in larger -numbers, though they nowhere live in such high ratios to the Indian as -on the coast and in the lower valleys near the coast. With few -exceptions the white population of Peru is distributed in response to -favorable combinations of climate, soil, accessibility, and general -opportunities to secure a living without extreme sacrifice. - -These facts are stated in a simple way, for I wish to emphasize the -statement that the Indian population responds to quite other stimuli. -Most of the luxuries and comforts of the whites mean nothing to the -Indian. The machine-made woolens of the importers will probably never -displace his homespun llama-wool clothing. His implements are few in -number and simple in form. His tastes in food are satisfied by the few -products of his fields and his mountain flocks. Thus he has lived for -centuries and is quite content to live today. Only coca and brandy tempt -him to engage in commerce, to toil now and then in the hot valleys, and -to strive for more than the bare necessities of life. Therefore it -matters very little to him if his home town is isolated, or the -resources support but a small group of people. He is so accustomed to a -solitary existence in his ramblings with his flocks that a village of -fifty houses offers social enjoyments of a high order. Where a white -perishes for lack of society the Indian finds himself contented. -Finally, he is not subject to the white man's exploitation when he lives -in remote places. The pastures are extensive and free. The high valley -lands are apportioned by the alcalde according to ancient custom. His -life is unrestricted by anything but the common law and he need have no -care for the morrow, for the seasons here are almost as fixed as the -stars. - -Thus we have a sort of segregation of whites in the lower places where a -modern type of life is maintained and of Indians in the higher places -where they enjoy advantages that do not appeal to the whites. Above -8,000 feet the density of the white population bears a close inverse -proportion to the altitude, excepting in the case of the largest valleys -whose size brings together such numbers as to tempt the commercial and -exploiting whites to live in them. Furthermore, we should find that high -altitude, limited size, and greater isolation are everywhere closely -related to increasing immorality or decreasing character among the -whites. So to the low Indian population there is thus added the lowest -of the white population. Moreover, because it yields the largest -returns, the chief business of these whites is the sale of coca and -brandy and the downright active debauchery of the Indian. This is all -the easier for them because the isolated Indian, like the average -isolated white, has only a low and provincial standard of morality and -gets no help from such stimulation as numbers usually excite. - -For example, the Anta basin at harvest time is one of the fairest sights -in Peru. Sturdy laborers are working diligently. Their faces are bright -and happy, their skin clear, their manner eager and animated. They sing -at their work or gather about their mild _chicha_ and drink to the -patron saints of the harvest. The huts are filled with robust children; -all the yards are turned into threshing floors; and from the stubbly -hillslopes the shepherd blows shrill notes upon his barley reeds and -bamboo flute. There is drinking but there is little disorder and there -is always a sober remnant that exercises a restraining influence upon -the group. - -In the most remote places of all one may find mountain groups of a high -order of morality unaffected by the white man or actually shunning him. -Clear-eyed, thick-limbed, independent, a fine, sturdy type of man this -highland shepherd may be. But in the town he succumbs to the temptation -of drink. Some writers have tried to make him out a superior to the -plains and low valley type. He is not that. The well-regulated groups of -the lower elevations are far superior intellectually and morally in -spite of the fact that the poorly regulated groups may fall below the -highland dweller in morality. The coca-chewing highlander is a clod. -Surely, as a whole, the mixed breed of the coastal valleys is a far -worthier type, save in a few cases where a Chinese or negroid element or -both have led to local inferiority. And surely, also, that is the worst -combination which results in adding the viciousness of the inferior or -debased white to the stupidity of the highland Indian. It is here that -the effects of geography are most apparent. If the white is tempted in -large numbers because of exceptional position or resources, as at La -Paz, the rule of altitude may have an exception. And other exceptions -there are not due to physical causes, for character is practically never -a question of geography alone. There is the spiritual factor that may -illumine a strong character and through his agency turn a weak community -into a powerful one, or hold a weakened group steadfast against the -forces of disintegration. Exceptions arise from this and other causes -and yet with them all in mind the geographic factor seems predominant in -the types illustrated herewith.[17] - - - - -CHAPTER VIII - -THE COASTAL DESERT - - -To the wayfarer from the bleak mountains the warm green valleys of the -coastal desert of Peru seem like the climax of scenic beauty. The -streams are intrenched from 2,000 to 4,000 feet, and the valley walls in -some places drop 500 feet by sheer descents from one level to another. -The cultivated fields on the valley floors look like sunken gardens and -now and then one may catch the distant glint of sunlight on water. The -broad white path that winds through vineyards and cotton-fields, follows -the foot of a cliff, or fills the whole breadth of a gorge is the -waste-strewn, half-dry channel of the river. In some places almost the -whole floor is cultivated from one valley wall to the other. In other -places the fields are restricted to narrow bands between the river and -the impending cliffs of a narrow canyon. Where tributaries enter from -the desert there may be huge banks of mud or broad triangular fans -covered with raw, infertile earth. The picture is generally touched with -color--a yellow, haze-covered horizon on the bare desert above, brown -lava flows suspended on the brink of the valley, gray-brown cliffs, and -greens ranging from the dull shade of algarrobo, olive and fig trees, to -the bright shade of freshly irrigated alfalfa pastures. - -After several months' work on the cold highlands, where we rode almost -daily into hailstorms or wearisome gales, we came at length to the -border of the valley country. It will always seem to me that the weather -and the sky conspired that afternoon to reward us for the months of toil -that lay behind. And certainly there could be no happier place to -receive the reward than on the brink of the lava plateau above -Chuquibamba. There was promise of an extraordinary view in the growing -beauty of the sky, and we hurried our tired beasts forward so that the -valley below might also be included in the picture. The head of the -Majes Valley is a vast hollow bordered by cliffs hundreds of feet high, -and we reached the rim of it only a few minutes before sunset. - -[Illustration: FIG. 63--The deep fertile Majes Valley below Cantas. -Compare with Fig. 6 showing the Chili Valley at Arequipa.] - -[Illustration: FIG. 64--The Majes Valley, desert coast, western Peru. -The lighter patches on the valley floor are the gravel beds of the river -at high water. Much of the alluvial land is still uncleared.] - -I remember that we halted beside a great wooden cross and that our -guide, dismounting, walked up to the foot of it and kissed and embraced -it after the custom of the mountain folk when they reach the head of a -steep "cuesta." Also that the trail seemed to drop off like a stairway, -which indeed it was.[18] Everything else about me was completely -overshadowed by snowy mountains, colored sky, and golden-yellow desert. -One could almost forget the dark clouds that gather around the great -mass of Coropuna and the bitter winds that creep down from its glaciers -at night--it seemed so friendly and noble. Behind it lay bulky masses of -rose-tinted clouds. We had admired their gay colors only a few minutes, -when the sun dropped behind the crest of the Coast Range and the last of -the sunlight played upon the sky. It fell with such marvelously swift -changes of color upon the outermost zone of clouds as these were shifted -with the wind that the eye had scarcely time to comprehend a tint before -it was gone and one more beautiful still had taken its place. The -reflected sunlight lay warm and soft upon the white peaks of Coropuna, -and a little later the Alpine glow came out delicately clear. - -When we turned from this brilliant scene to the deep valley, we found -that it had already become so dark that its greens had turned to black, -and the valley walls, now in deep shadow, had lost half their splendor. -The color had not left the sky before the lights of Chuquibamba began to -show, and candles twinkled from the doors of a group of huts close under -the cliff. We were not long in starting the descent. Here at last were -friendly habitations and happy people. I had worked for six weeks -between 12,000 and 17,000 feet, constantly ill from mountain sickness, -and it was with no regret that I at last left the plateau and got down -to comfortable altitudes. It seemed good news when the guide told me -that there were mosquitoes in the marshes of Camaná. Any low, hot land -would have seemed like a health resort. I had been in the high country -so long that, like the Bolivian mining engineer, I wanted to get down -not only to sea level, but below it! - -[Illustration: FIG. 65--Regional diagram to show the physical relations -in the coastal desert of Peru. For location, see Fig. 20.] - -If the reader will examine Figs. 65 and 66, and the photographs that -accompany them, he may gain an idea of the more important features of -the coastal region. We have already described, in Chapters V and VII, -the character of the plateau region and its people. Therefore, we need -say little in this place of the part of the Maritime Cordillera that is -included in the figure. Its unpopulated rim (see p. 54), the -semi-nomadic herdsmen and shepherds from Chuquibamba that scour its -pastures in the moist vales about Coropuna, and the gnarled and stunted -trees at 13,000 feet (3,960 m.) which partly supply Chuquibamba with -firewood, are its most important features. A few groups of huts just -under the snowline are inhabited for only a part of the year. The -delightful valleys are too near and tempting. Even a plateau Indian -responds to the call of a dry valley, however he may shun the moist, -warm valleys on the eastern border of the Cordillera. - -[Illustration: FIG. 66--Irrigated and irrigable land of the coastal belt -of Peru. The map exhibits in a striking manner how small a part of the -whole Pacific slope is available for cultivation. Pasture grows over all -but the steepest and the highest portions of the Cordillera to the right -of (above) the dotted line. Another belt of pasture too narrow to show -on the map, grows in the fog belt on the seaward slopes of the Coast -Range. Scale, 170 miles to the inch.] - -The greater part of the coastal region is occupied by the desert. Its -outer border is the low, dry, gentle, eastward-facing slope of the Coast -Range. Its inner border is the foot of the steep descent that marks the -edge of the lava plateau. This descent is a fairly well-marked line, -here and there broken by a venturesome lava flow that extends far out -from the main plateau. Within these definite borders the desert extends -continuously northwestward for hundreds of miles along the coast of Peru -from far beyond the Chilean frontier almost to the border of Ecuador. It -is broken up by deep transverse valleys and canyons into so-called -"pampas," each of which has a separate name; thus west of Arequipa -between the Vitor and Majes valleys are the "Pampa de Vitor" and the -"Pampa de Sihuas," and south of the Vitor is the "Pampa de Islay." - -The pampa surfaces are inclined in general toward the sea. They were -built up to their present level chiefly by mountain streams before the -present deep valleys were cut, that is to say, when the land was more -than a half-mile lower. Some of their material is wind-blown and on the -walls of the valleys are alternating belts of wind-blown and water-laid -strata from one hundred to four hundred feet thick as if in past ages -long dry and long wet periods had succeeded each other. The wind has -blown sand and dust from the desert down into the valleys, but its chief -work has been to drive the lighter desert waste up partly into the -mountains and along their margins, partly so high as to carry it into -the realm of the lofty terrestrial winds, whence it falls upon surfaces -far distant from the fields of origin. There are left behind the heavier -sand which the wind rolls along on the surfaces and builds into -crescentic dunes called médanos, and the pebbles that it can sandpaper -but cannot remove bodily. Thus there are belts of dunes, belts of -irregular sand drifts, and belts of true desert "pavement" (a residual -mantle of faceted pebbles and irregular stones). - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM, DIRECTOR - -CAMANÁ QUADRANGLE - -(_Aplao_)] - -Yet another feature of the desert pampa are the "dry" valleys that join -the through-flowing streams at irregular intervals, as shown in the -accompanying regional diagram. If one follow a dry valley to its head -he will find there a set of broad and shallow tributaries. Sand drifts -may clog them and appear to indicate that water no longer flows through -them. They are often referred to by unscientific travelers as evidences -of a recent change of climate. I had once the unusual opportunity (in -the mountains of Chile) of seeing freshly fallen snow melted rapidly and -thus turned suddenly into the streams. In 1911 this happened also at San -Pedro de Atacama, northern Chile, right in the desert at 8,000 feet -(2,440 m.) elevation, and in both places the dry, sand-choked valleys -were cleaned out and definite channels reëstablished. From a large -number of facts like these we know that the dry valleys represent the -work of the infrequent rains. No desert is absolutely rainless, although -until recently it was the fashion to say so. Naturally the wind, which -works incessantly, partly offsets the work of the water. Yet the wind -can make but little impression upon the general outlines of the dry -valleys. They remain under the dominance of the irregular rains. These -come sometimes at intervals of three or four years, again at intervals -of ten to fifteen years, and some parts of the desert have probably been -rainless for a hundred years. Some specific cases are discussed in the -chapter on Climate. - -The large valleys of the desert zone have been cut by snow-fed streams -and then partly filled again so that deep waste lies on their floors and -abuts with remarkable sharpness against the bordering cliffs (Fig. 155). -Extensive flats are thus available for easy cultivation, and the -through-flowing streams furnish abundant water to the irrigating canals. -The alluvial floor begins almost at the foot of the steep western slope -of the lava plateau, but it is there stony and coarse--hence -Chuquibamba, or plain of stones (chuqui = stone; bamba = plain). Farther -down and about half-way between Chuquibamba and Aplao (Camaná -Quadrangle) it is partly covered with fresh mud and sand flows from the -bordering valley walls and the stream is intrenched two hundred feet. A -few miles above Aplao the stream emerges from its narrow gorge and -thenceforth flows on the surface of the alluvium right to the sea. -Narrow places occur between Cantas and Aplao, where there is a -projection of old and hard quartzitic rock, and again above Camaná, -where the stream cuts straight across the granite axis of the Coast -Range. Elsewhere the rock is either a softer sandstone or still -unindurated sands and gravels, as at the top of the desert series of -strata that are exposed on the valley wall. The changing width of the -valley is thus a reflection of the changing hardness of the rock. - -There is a wide range of products between Chuquibamba at 10,000 feet -(3,050 m.) at the head of the valley and Camaná near the valley mouth. -At the higher levels fruit will not grow--only alfalfa, potatoes, and -barley. A thousand feet below Chuquibamba fruit trees appear. Then -follows a barren stretch where there are mud flows and where the river -is intrenched. Below this there is a wonderful change in climate and -products. The elevation falls off 4,000 feet and the first cultivated -patches below the middle unfavorable section are covered with grape -vines. Here at 3,000 feet (900 m.) elevation above the sea begin the -famous vineyards of the Majes Valley, which support a wine industry that -dates back to the sixteenth century. Some of the huge buried earthenware -jars for curing the wine at Hacienda Cantas were made in the reign of -Philip II. - -The people of Aplao and Camaná are among the most hospitable and -energetic in Peru, as if these qualities were but the reflection of the -bounty of nature. Nowhere could I see evidences of crowding or of the -degeneracy or poverty that is so often associated with desert people. -Water is always plentiful; sometimes indeed too plentiful, for floods -and changes in the bed of the river are responsible for the loss of a -good deal of land. This abundance of water means that both the small and -the large landowners receive enough. There are none of the troublesome -official regulations, as in the poorer valleys with their inevitable -favoritism or downright graft. Yet even here the valley is not fully -occupied; at many places more land could be put under cultivation. The -Belaunde brothers at Cantas have illustrated this in their new cotton -plantation, where clearings and new canals have turned into cultivated -fields tracts long covered with brush. - -The Majes Valley sorely lacks an adequate port. Its cotton, sugar, and -wine must now be shipped to Camaná and thence to Mollendo, either by a -small bi-weekly boat, or by pack-train over the coast trail to Quilca, -where ocean steamers call. This is so roundabout a way that the planters -of the mid-valley section and the farmers of the valley head now export -their products over the desert trail from Cantas to Vitor on the -Mollendo-Arequipa railroad, whence they can be sent either to the cotton -mills or the stores of Arequipa, the chief distributing market of -southern Peru, or to the ocean port. - -The foreshore at Camaná is low and marshy where the salt water covers -the outer edge of the delta. In the hollow between two headlands a broad -alluvial plain has been formed, through which the shallow river now -discharges. Hence the natural indentation has been filled up and the -river shoaled. To these disadvantages must be added a third, the -shoaling of the sea bottom, which compels ships to anchor far off shore. -Such shoals are so rare on this dry and almost riverless coast as to be -a menace to navigation. The steamer _Tucapelle_, like all west-coast -boats, was sailing close to the unlighted shore on a very dark night in -April, 1911, when the usual fog came on. She struck the reef just off -Camaná. Half of her passengers perished in trying to get through the -tremendous surf that broke over the bar. The most practicable scheme for -the development of the port would seem to be a floating dock and tower -anchored out of reach of the surf, and connected by cable with a railway -on shore. Harbor works would be extraordinarily expensive. The valley -can support only a modest project. - -The relations of Fig. 65, representing the Camaná-Vitor region, are -typical of southern Peru, with one exception. In a few valleys the -streams are so small that but little water is ever found beyond the foot -of the mountains, as at Moquegua. In the Chili Valley is Arequipa (8,000 -feet), right at the foot of the big cones of the Maritime Cordillera -(see Fig. 6). The green valley floor narrows rapidly and cultivation -disappears but a few miles below the town. Outside the big valleys -cultivation is limited to the best spots along the foot of the Coast -Range, where tiny streams or small springs derive water from the zone of -clouds and fogs on the seaward slopes of the Coast Range. Here and there -are olive groves, a vegetable garden, or a narrow alfalfa meadow, -watered by uncertain springs that issue below the hollows of the -bordering mountains. - -[Illustration: FIG. 67--Irrigated and irrigable land in the Ica Valley -of the coastal desert of Peru.] - -[Illustration: FIG. 68--The projected canal to convey water from the -Atlantic slope to the Pacific slope of the Maritime Cordillera.[19]] - -In central and northern Peru the coastal region has aspects quite -different from those about Camaná. At some places, for example north of -Cerro Azul, the main spurs of the Cordillera extend down to the shore. -There is neither a low Coast Range nor a broad desert pampa. In such -places flat land is found only on the alluvial fans and deltas. Lima and -Callao are typical. Fig. 66, compiled from Adams's reports on the water -resources of the coastal region of Peru, shows this distinctive feature -of the central region. Beyond Salaverry extends the northern region, -where nearly all the irrigated land is found some distance back from the -shore. The farther north we go the more marked is this feature, because -the coastal belt widens. Catacaos is several miles from the sea, and -Piura is an interior place. At the extreme north, where the rains begin, -as at Tumbez, the cultivated land once more extends to the coast. - -[Illustration: FIG. 69--A stream of the intermittent type in the coastal -desert of Peru. Depth of water in the Puira River at Puira, 1905. (Bol. -de Minas del Perú, 1906, No. 45, p. 2.)] - -[Illustration: FIG. 70--A stream of the perennial type in the coastal -desert of Peru. Depth of water in the Chira River at Sullana, 1905. Data -from May to September are approximate. (Bol. de Minas del Perú, 1906, -No. 45, p. 2.)] - -These three regions contain all the fertile coastal valleys of Peru. The -larger ones are impressive--with cities, railways, ports, and land in a -high state of cultivation. But they are after all only a few hundred -square miles in extent. They contain less than a quarter of the people. -The whole Pacific slope from the crest of the Cordillera has about -15,000 square miles (38,850 sq. km.), and of this only three per cent is -irrigated valley land, as shown in Fig. 66. Moreover, only a small -additional amount may be irrigated, perhaps one half of one per cent. -Even this amount may be added not only by a better use of the water but -also by the diversion of streams and lakes from the Atlantic to the -Pacific. Figs. 67 and 68 represent such a project, in which it is -proposed to carry the water of Lake Choclococha through a canal and -tunnel under the continental divide and so to the head of the Ica -Valley. A little irrigation can be and is carried on by the use of well -water, but this will never be an important source because of the great -depth to the ground water, and the fact that it, too, depends ultimately -upon the limited rains. - -The inequality of opportunity in the various valleys of the coastal -region depends in large part also upon inequality of river discharge. -This is dependent chiefly upon the sources of the streams, whether in -snowy peaks of the main Cordillera with fairly constant run-off, or in -the western spurs where summer rains bring periodic high water. A third -type has high water during the time of greatest snow melting, combined -with summer rains, and to this class belongs the Majes Valley with its -sources in the snow-cap of Coropuna. The other two types are illustrated -by the accompanying diagrams for Puira and Chira, the former -intermittent in flow, the latter fairly constant.[20] - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM DIRECTOR - -APLAO QUADRANGLE] - - - - -CHAPTER IX - -CLIMATOLOGY OF THE PERUVIAN ANDES - - -CLIMATIC BELTS - -The noble proportions of the Peruvian Andes and their position in -tropical latitudes have given them climatic conditions of great -diversity. Moreover, their great breadth and continuously lofty summits -have distributed the various climatic types over spaces sufficiently -ample to affect large and important groups of people. When we add to -this the fact that the topographic types developed on a large scale are -distributed at varying elevations, and that upon them depend to a large -degree the chief characteristics of the soil, another great factor in -human distribution, we are prepared to see that the Peruvian Andes -afford some striking illustrations of combined climatic and topographic -control over man. - -The topographic features in their relations to the people have been -discussed in preceding chapters. We shall now examine the corresponding -effects of climate. It goes without saying that the topographic and -climatic controls cannot and need not be kept rigidly apart. Yet it -seems desirable, for all their natural interdependence, to give them -separate treatment, since the physical laws upon which their -explanations depend are of course entirely distinct. Further, there is -an independent group of human responses to detailed climatic features -that have little or no connection with either topography or soil. - -The chief climatic belts of Peru run roughly from north to south in the -direction of the main features of the topography. Between 13° and 18° -S., however, the Andes run from northwest to southeast, and in short -stretches nearly west-east, with the result that the climatic belts -likewise trend westward, a condition well illustrated on the -seventy-third meridian. Here are developed important climatic features -not found elsewhere in Peru. The trade winds are greatly modified in -direction and effects; the northward-trending valleys, so deep as to be -secluded from the trades, have floors that are nearly if not quite arid; -a restricted coastal region enjoys a heavier rainfall; and the snowline -is much more strongly canted from west to east than anywhere else in the -long belt of mountains from Patagonia to Venezuela. These exceptional -features depend, however, upon precisely the same physical laws as the -normal climatic features of the Peruvian Andes. They can, therefore, be -more easily understood after attention has been given to the larger -aspects of the climatic problem of which they form a part. - -The critical relations of trade winds, lofty mountains, and ocean -currents that give distinction to Peruvian climate are shown in Figs. 71 -to 73. From them and Fig. 74 it is clear that the two sides of the -Peruvian mountains are in sharp contrast climatically. The eastern -slopes have almost daily rains, even in the dry season, and are clothed -with forest. The western leeward slopes are so dry that at 8,000 feet -even the most drought-resisting grasses stop--only low shrubs live below -this level, and over large areas there is no vegetation whatever. An -exception is the Coast Range, not shown on these small maps, but -exhibited in the succeeding diagram. These have moderate rains on their -seaward (westerly) slopes during some years and grass and shrubby -vegetation grow between the arid coastal terraces below them and the -parched desert above. The greatest variety of climate is enjoyed by the -mountain zone. Its deeper valleys and basins descend to tropical levels; -its higher ranges and peaks are snow-covered. Between are the climates -of half the world compressed, it may be, between 6,000 and 15,000 feet -of elevation and with extremes only a day's journey apart. - -[Illustration: FIG. 71--The three chief topographic regions of Peru.] - -[Illustration: FIG. 72--The wind belts of Peru and ocean currents of -adjacent waters.] - -[Illustration: FIG. 73--The climatic belts of Peru.] - -[Illustration: FIG. 74--Belts of vegetation in Peru.] - -In the explanation of these contrasts we have to deal with relatively -simple facts and principles; but the reader who is interested chiefly in -the human aspects of the region should turn to p. 138 where the effects -of the climate on man are set forth. The ascending trades on the eastern -slopes pass successively into atmospheric levels of diminishing -pressure; hence they expand, deriving the required energy for expansion -from the heat of the air itself. The air thereby cooled has a lower -capacity for the retention of water vapor, a function of its -temperature; the colder the air the less water vapor it can take up. As -long as the actual amount of water vapor in the air is less than that -which the air can hold, no rain falls. But the cooling process tends -constantly to bring the warm, moist, ascending air currents to the limit -of their capacity for water vapor by diminishing the temperature. -Eventually the air is saturated and if the capacity diminishes still -further through diminishing temperature some of the water vapor must be -condensed from a gaseous to a liquid form and be dropped as rain. - -The air currents that rise thousands of feet per day on the eastern -slopes of the Andes pass again and again through this practically -continuous process and the eastern aspect of the mountains is kept -rain-soaked the whole year round. For the trades here have only the -rarest reversals. Generally they blow from the east day after day and -repeat a fixed or average type of weather peculiar to that part of the -tropics under their steady domination. During the southern summer, when -the day-time temperature contrasts between mountains and plains are -strongest, the force of the trade wind is greatly increased and likewise -the rapidity of the rain-making processes. Hence there is a distinct -seasonal difference in the rainfall--what we call, for want of a better -name, a "wet" and a "dry" season. - -On the western or seaward slopes of the Peruvian Andes the trade winds -descend, and the process of rain-making is reversed to one of -rain-taking. The descending air currents are compressed as they reach -lower levels where there are progressively higher atmospheric pressures. -The energy expended in the process is expressed in the air as heat, -whence the descending air gains steadily in temperature and capacity for -water vapor, and therefore is a drying wind. Thus the leeward, western -slopes of the mountains receive little rain and the lowlands on that -side are desert. - - -THE CLIMATE OF THE COAST - -A series of narrow but pronounced climatic zones coincide with the -topographic subdivisions of the western slope of the country between the -crest of the Maritime Cordillera and the Pacific Ocean. This belted -arrangement is diagrammatically shown in Fig. 75. From the zone of lofty -mountains with a well-marked summer rainy season descent is made by -lower slopes with successively less and less precipitation to the desert -strip, where rain is only known at irregular intervals of many years' -duration. Beyond lies the seaward slope of the Coast Range, more or less -constantly enveloped in fog and receiving actual rain every few years, -and below it is the very narrow band of dry coastal terraces. - -[Illustration: FIG. 75--Topographic and climatic provinces in the -coastal region of Peru. The broadest division, into the zones of regular -annual rains and of irregular rains, occurs approximately at 8,000 feet -but is locally variable. To the traveler it is always clearly defined by -the change in architecture, particularly of the house roofs. Those of -the coast are flat; those of the sierra are pitched to facilitate run -off.] - -The basic cause of the general aridity of the region has already been -noted; the peculiar circumstances giving origin to the variety in detail -can be briefly stated. They depend upon the meteorologic and -hydrographic features of the adjacent portion of the South Pacific Ocean -and upon the local topography. - -The lofty Andes interrupt the broad sweep of the southeast trades -passing over the continent from the Atlantic; and the wind circulation -of the Peruvian Coast is governed to a great degree by the high pressure -area of the South Pacific. The prevailing winds blow from the south and -the southeast, roughly paralleling the coast or, as onshore winds, -making a small angle with it. When the Pacific high pressure area is -best developed (during the southern winter), the southerly direction of -the winds is emphasized, a condition clearly shown on the Pilot Charts -of the South Pacific Ocean, issued by the U.S. Hydrographic Office. - -[Illustration: FIG. 76--Temperatures at Callao, June-September, 1912, -from observations taken by Captain A. Taylor, of Callao. Air -temperatures are shown by heavy lines; sea temperatures by light lines. -In view of the scant record for comparative land and water temperatures -along the Peruvian coast this record, short as it is, has special -interest.] - -The hydrographic feature of greatest importance is the Humboldt Current. -To its cold waters is largely due the remarkably low temperatures of the -coast.[21] In the latitude of Lima its mean surface temperature is about -10° below normal. Lima itself has a mean annual temperature 4.6° F. -below the theoretical value for that latitude, (12° S.). An accompanying -curve shows the low temperature of Callao during the winter months. From -mid-June to mid-September the mean was 61° F., and the annual mean is -only 65.6° F. (18° C.). The reduction in temperature is accompanied by a -reduction in the vapor capacity of the super-incumbent air, an effect of -which much has been made in explanation of the west-coast desert. That -it is a contributing though not exclusive factor is demonstrated in Fig. -77. Curve _A_ represents the hypothetical change of temperature on a -mountainous coast with temporary afternoon onshore winds from a _warm_ -sea. Curve _B_ represents the change of temperature if the sea be cold -(actual case of Peru). The more rapid rise of curve _B_ to the right of -X-X', the line of transition, and its higher elevation above its former -saturation level, as contrasted with _A_, indicates greater dryness -(lower relative humidity). There has been precipitation in case _A_, but -at a higher temperature, hence more water vapor remains in the air -after precipitation has ceased. Curve _B_ ultimately rises nearly to the -level of _A_, for with less water vapor in the air of case _B_ the -temperature rises more rapidly (a general law). Moreover, the higher the -temperature the greater the radiation. To summarize, curve _A_ rises -more slowly than curve _B_, (1) because of the greater amount of water -vapor it contains, which must have its temperature raised with that of -the air, and thus absorbs energy which would otherwise go to increase -the temperature of the air, and (2) because its loss of heat by -radiation is more rapid on account of its higher temperature. We -conclude from these principles and deductions that under the given -conditions a cold current intensifies, but does not cause the aridity of -the west-coast desert. - -[Illustration: FIG. 77--To show progressive lowering of saturation -temperature in a desert under the influence of the mixing process -whereby dry and cool air from aloft sinks to lower levels thus -displacing the warm surface air of the desert. The evaporated moisture -of the surface air is thus distributed through a great volume of upper -air and rain becomes increasingly rarer. Applied to deserts in general -it shows that the effect of any cosmic agent in producing climatic -change from moist to dry or dry to moist will be disproportionately -increased. The shaded areas C and C' represent the fog-covered slopes of -the Coast Range of Peru as shown in Fig. 92. X-X' represents the crest -of the Coast Range.] - -Curves _a_ and _b_ represent the rise of temperature in two contrasted -cases of warm and cold sea with the coastal mountains eliminated, so as -to simplify the principle applied to _A_ and _B_. The steeper gradient -of _b_ also represents the fact that the lower the initial temperature -the dryer will the air become in passing over the warm land. For these -two curves the transition line X-X' coincides with the crest of the -Coast Range. It will also be seen that curve _a_ is never so far from -the saturation level as curve _b_. Hence, unusual atmospheric -disturbances would result in heavier and more frequent showers. - -[Illustration: FIG. 78--Wind roses for Callao. The figures for the -earlier period (1897-1900) are drawn from data in the Boletín de la -Sociedad Geográfica de Lima, Vols. 7 and 8, 1898-1900: for the latter -period data from observations of Captain A. Taylor, of Callao. The -diameter of the circle represents the proportionate number of -observations when calm was registered.] - -[Illustration: FIG. 79--Wind roses for Mollendo. The figures are drawn -from data in Peruvian Meteorology (1892-1895), Annals of the -Astronomical Observatory of Harvard College, Vol. 30, Pt. 2, Cambridge, -Mass., 1906. Observations for an earlier period, Feb. 1889-March 1890, -(Id. Vol. 39, Pt. 1, Cambridge, Mass. 1890) record S. E. wind at 2 p. m. -97 per cent of the observation time.] - -[Illustration: FIG. 80--Wind roses for the summer and winter seasons of -the years 1911-1913. The diameter of the circle in each case shows the -proportion of calm. Figures are drawn from data in the Anuario -Meteorológico de Chile, Publications No. 3, (1911), 6 (1912) and 13 -(1913), Santiago, 1912, 1914, 1914.] - -Turning now to local factors we find on the west coast a regional -topography that favors a diurnal periodicity of air movement. The strong -slopes of the Cordillera and the Coast Range create up-slope or eastward -air gradients by day and opposite gradients by night. To this -circumstance, in combination with the low temperature of the ocean water -and the direction of the prevailing winds, is due the remarkable -development of the sea-breeze, without exception the most important -meteorological feature of the Peruvian Coast. Several graphic -representations are appended to show the dominance of the sea-breeze -(see wind roses for Callao, Mollendo, Arica, and Iquique), but interest -in the phenomenon is far from being confined to the theoretical. -Everywhere along the coast the _virazon_, as the sea-breeze is called in -contradistinction to the _terral_ or land-breeze, enters deeply into the -affairs of human life. According to its strength it aids or hinders -shipping; sailing boats may enter port on it or it may be so violent, -as, for example, it commonly is at Pisco, that cargo cannot be loaded or -unloaded during the afternoon. On the nitrate pampa of northern Chile -(20° to 25° S.) it not infrequently breaks with a roar that heralds its -coming an hour in advance. In the Majes Valley (12° S.) it blows gustily -for a half-hour and about noon (often by eleven o'clock) it settles down -to an uncomfortable gale. For an hour or two before the sea-breeze -begins the air is hot and stifling, and dust clouds hover about the -traveler. The maximum temperature is attained at this time and not -around 2.00 P. M. as is normally the case. Yet so boisterous is the noon -wind that the laborers time their siesta by it, and not by the high -temperatures of earlier hours. In the afternoon it settles down to a -steady, comfortable, and dustless wind, and by nightfall the air is once -more calm. - -[Illustration: FIG. 81--Wind roses for Iquique for the summer and winter -seasons of the years 1911-1913. The diameter of the circle in each case -shows the proportion of calm. For source of data see Fig. 80.] - -Of highest importance are the effects of the sea-breeze on -precipitation. The bold heights of the Coast Range force the nearly or -quite saturated air of the sea-wind to rise abruptly several thousand -feet, and the adiabatic cooling creates fog, cloud, and even rain on the -seaward slope of the mountains. The actual form and amount of -precipitation both here and in the interior region vary greatly, -according to local conditions and to season and also from year to year. -The coast changes height and contour from place to place. At Arica the -low coastal chain of northern Chile terminates at the Morro de Arica. -Thence northward is a stretch of open coast, with almost no rainfall and -little fog. But in the stretch of coast between Mollendo and the Majes -Valley a coastal range again becomes prominent. Fog enshrouds the hills -almost daily and practically every year there is rain somewhere along -their western aspect. - -[Illustration: FIG. 82--The wet and dry seasons of the Coast Range and -the Cordillera are complementary in time. The "wet" season of the former -occurs during the southern winter; the cloud bank on the seaward slopes -of the hills is best developed at that time and actual rains may occur.] - -[Illustration: FIG. 83--During the southern summer the seaward slopes of -the Coast Range are comparatively clear of fog. Afternoon cloudiness is -characteristic of the desert and increases eastward (compare Fig. 86), -the influence of the strong sea winds as well as that of the trades -(compare Fig. 93B) being felt on the lower slopes of the Maritime -Cordillera.] - -During the southern winter the cloud bank of the coast is best developed -and precipitation is greatest. At Lima, for instance, the clear skies of -March and April begin to be clouded in May, and the cloudiness grows -until, from late June to September, the sun is invisible for weeks at a -time. This is the period of the garua (mist) or the "tiempo de lomas," -the "season of the hills," when the moisture clothes them with verdure -and calls thither the herds of the coast valleys. - -[Illustration: FIG. 84--Cloudiness at Callao. Figures are drawn from -data in the Boletín de la Sociedad Geográfica de Lima, Vols. 7 and 8, -1898-1900. They represent the conditions at three observation hours -during the summers (Dec., Jan.) of 1897-1898, 1898-1899, 1899-1900 and -the winters (June, July) of 1898 and 1899.] - -During the southern summer on account of the greater relative difference -between the temperatures of land and water, the sea-breeze attains its -maximum strength. It then accomplishes its greatest work in the desert. -On the pampa of La Joya, for example, the sand dunes move most rapidly -in the summer. According to the Peruvian Meteorological Records of the -Harvard Astronomical Observatory the average movement of the dunes from -April to September, 1900, was 1.4 inches per day, while during the -summer months of the same year it was 2.7 inches. In close agreement are -the figures for the wind force, the record for which also shows that 95 -per cent of the winds with strength over 10 miles per hour blew from a -southerly direction. Yet during this season the coast is generally -clearest of fog and cloud. The explanation appears to lie in the -exceedingly delicate nature of the adjustments between the various -rain-making forces. The relative humidity of the air from the sea is -always high, but on the immediate coast is slightly less so in summer -than in winter. Thus in Mollendo the relative humidity during the winter -of 1895 was 81 per cent; during the summer 78 per cent. Moreover, the -temperature of the Coast Range is considerably higher in summer than in -winter, and there is a tendency to reëvaporation of any moisture that -may be blown against it. The immediate shore, indeed, may still be -cloudy as is the case at Callao, which actually has its cloudiest season -in the summer but the hills are comparatively clear. In consequence the -sea-air passes over into the desert, where the relative increase in -temperature has not been so great (compare Mollendo and La Joya in the -curve for mean monthly temperature), with much higher vapor content than -in winter. The relative humidity for the winter season at La Joya, 1895, -was 42.5 per cent; for the summer season 57 per cent. The influence of -the great barrier of the Maritime Cordillera, aided doubtless by -convectional rising, causes ascent of the comparatively humid air and -the formation of cloud. Farther eastward, as the topographic influence -is more strongly felt, the cloudiness increases until on the border -zone, about 8,000 feet in elevation, it may thicken to actual rain. Data -have been selected to demonstrate this eastern gradation of -meteorological phenomena. - -[Illustration: FIG. 85--Temperature curves for Mollendo (solid lines) -and La Joya (broken lines) April, 1894, to December, 1895, drawn from -data in Peruvian Meteorology, 1892-1895, Annals of the Astronomical -Observatory of Harvard College, Vol. 49, Pt. 2, Cambridge, Mass., 1908. -The approximation of the two curves of maximum temperature during the -winter months contrasts with the well-maintained difference in minimum -temperatures throughout the year.] - -[Illustration: FIG. 86--Mean monthly cloudiness for Mollendo (solid -line) and La Joya (broken line) from April, 1892, to December, 1895. -Mollendo, 80 feet elevation, has the maximum winter cloudiness -characteristic of the seaward slope of the Coast Range (compare Fig. 82) -while the desert station of La Joya, 4,140 feet elevation, has typical -summer cloudiness (compare Fig. 83). Figures are drawn from data in -Peruvian Meteorology, 1892-1895, Annals of the Astronomical Observatory -of Harvard College, Vol. 49, Pt. 2, Cambridge, Mass., 1908.] - -[Illustration: FIG. 87--Wind roses for La Joya for the period April, -1892, to December, 1895. Compare the strong afternoon indraught from the -south with the same phenomenon at Mollendo, Fig. 79. Figures drawn from -data in Peruvian Meteorology, 1892-1895, Annals of the Astronomical -Observatory of Harvard College, Vol. 39, Pt. 2, Cambridge, Mass., 1906.] - -At La Joya, a station on the desert northeast of Mollendo at an -elevation of 4,140 feet, cloudiness is always slight, but it increases -markedly during the summer. Caraveli, at an altitude of 5,635 feet,[22] -and near the eastern border of the pampa, exhibits a tendency toward the -climatic characteristics of the adjacent zone. Data for a camp station -out on the pampa a few leagues from the town, were collected by Mr. J. -P. Little of the staff of the Peruvian Expedition of 1912-13. They -relate to the period January to March, 1913. Wind roses for these months -show the characteristic light northwesterly winds of the early morning -hours, in sharp contrast with the strong south and southwesterly -indraught of the afternoon. The daily march of cloudiness is closely -coördinated. Quotations from Mr. Little's field notes follow: - -"In the morning there is seldom any noticeable wind. A breeze starts at -10 A. M., generally about 180° (i. e. due south), increases to 2 or 3 -velocity at noon, having veered some 25° to the southwest. It reaches a -maximum velocity of 3 to 4 at about 4.00 P. M., now coming about 225° -(i. e. southwest). By 6 P. M. the wind has died down considerably and -the evenings are entirely free from it. The wind action is about the -same every day. It is not a cold wind and, except with the fog, not a -damp one, for I have not worn a coat in it for three weeks. It has a -free unobstructed sweep across fairly level pampas.... At an interval of -every three or four days a dense fog sweeps up from the southwest, dense -enough for one to be easily lost in it. It seldom makes even a sprinkle -of rain, but carries heavy moisture and will wet a man on horseback in -10 minutes. It starts about 3 P.M. and clears away by 8.00 P. M..... -During January, rain fell in camp twice on successive days, starting at -3.00 P. M. and ceasing at 8.00 P. M. It was merely a light, steady rain, -more the outcome of a dense fog than a rain-cloud of quick approach. In -Caraveli, itself, I am told that it rains off and on all during the -month in short, light showers." This record is dated early in February -and, in later notes, that month and March are recorded rainless. - -[Illustration: FIG. 88--Wind roses for a station on the eastern border -of the Coast Desert near Caraveli during the summer (January to March) -of 1913. Compare with Fig. 87. The diameter of the circle in each case -represents the proportion of calm. Note the characteristic morning -calm.] - -Chosica (elevation 6,600 feet), one of the meteorological stations of -the Harvard Astronomical Observatory, is still nearer the border. It -also lies farther north, approximately in the latitude of Lima, and this -in part may help to explain the greater cloudiness and rainfall. The -rainfall for the year 1889-1890 was 6.14 inches, of which 3.94 fell in -February. During the winter months when the principal wind observations -were taken, over 90 per cent showed noon winds from a southerly -direction while in the early morning northerly winds were frequent. It -is also noteworthy that the "directions of the upper currents of the -atmosphere as recorded by the motion of the clouds was generally between -N. and E." Plainly we are in the border region where climatic influences -are carried over from the plateau and combine their effects with those -from Pacific sources. Arequipa, farther south, and at an altitude of -7,550 feet, resembles Chosica. For the years 1892 to 1895 its mean -rainfall was 5.4 inches. - -[Illustration: FIG. 89--Cloudiness at the desert station of Fig. 88 -(near Caraveli), for the summer (January to March) of 1913.] - -Besides the seasonal variations of precipitation there are longer -periodic variations that are of critical importance on the Coast Range. -At times of rather regular recurrence, rains that are heavy and general -fall there. Every six or eight years is said to be a period of rain, but -the rains are also said to occur sometimes at intervals of four years or -ten years. The regularity is only approximate. The years of heaviest -rain are commonly associated with an unusual frequency of winds from the -north, and an abnormal development of the warm current, El Niño, from -the Gulf of Guayaquil. Such was the case in the phenomenally rainy year -of 1891. The connection is obscure, but undoubtedly exists. - -The effects of the heavy rains are amazing and appear the more so -because of the extreme aridity of the country east of them. During the -winter the desert traveler finds the air temperature rising to -uncomfortable levels. Vegetation of any sort may be completely lacking. -As he approaches the leeward slope of the Coast Range, a cloud mantle -full of refreshing promise may be seen just peeping over the crest (Fig. -91). Long, slender cloud filaments project eastward over the margin of -the desert. They are traveling rapidly but they never advance far over -the hot wastes, for their eastern margins are constantly undergoing -evaporation. At times the top of the cloud bank rises well above the -crest of the Coast Range, and it seems to the man from the temperate -zone as if a great thunderstorm were rising in the west. But for all -their menace of wind and rain the clouds never get beyond the desert -outposts. In the summer season the aspect changes, the heavy yellow sky -of the desert displaces the murk of the coastal mountains and the -bordering sea. - -[Illustration: FIG. 90--Cloudiness at Chosica, July, 1889, to September, -1890. Chosica, a station on the Oroya railroad east of Lima, is situated -on the border region between the desert zone of the coast and the -mountain zone of yearly rains. The minimum cloudiness recorded about 11 -a. m. is shown by a broken line; the maximum cloudiness, about 7 p. m., -by a dotted line, and the mean for the 24 hours by a heavy solid line. -The curves are drawn from data in Peruvian Meteorology, 1889-1890, -Annals of the Astronomical Observatory of Harvard College, Vol. 39, Pt. -1, Cambridge, Mass., 1899.] - -It is an age-old strife renewed every year and limited to a narrow field -of action, wonderfully easy to observe. We saw it in its most striking -form at the end of the winter season in October, 1911, and for more than -a day watched the dark clouds rise ominously only to melt into nothing -where the desert holds sway. At night we camped beside a scum-coated -pool of alkali water no larger than a wash basin. It lay in a valley -that headed in the Coast Range, and carried down into the desert a mere -trickle that seeped through the gravels of the valley floor. A little -below the pool the valley cuts through a mass of granite and becomes a -steep-walled gorge. The bottom is clogged with waste, here boulders, -there masses of both coarse and fine alluvium. The water in the valley -was quite incapable of accomplishing any work except that associated -with solution and seepage, and we saw it in the wet season of an -unusually wet year. Clearly there has been a diminution in the water -supply. But time prevented us from exploring this particular valley to -its head, to see if the reduction were due to a change of climate, or -only to capture of the head-waters by the vigorous rain-fed streams that -enjoy a favorable position on the wet seaward slopes and that are -extending their watershed aggressively toward the east at the expense of -their feeble competitors in the dry belt. - -An early morning start enabled me to witness the whole series of changes -between the clear night and the murky day, and to pass in twelve hours -from the dry desert belt through the wet belt, and emerge again into the -sunlit terraces at the western foot of the Coast Range. Two hours before -daylight a fog descended from the hills and the going seemed to be -curiously heavy for the beasts. At daybreak my astonishment was great to -find that it was due to the distinctly moist sand. We were still in the -desert. There was not a sign of a bush or a blade of grass. Still, the -surface layer, from a half inch to an inch thick, was really wet. The -fog that overhung the trail lifted just before sunrise, and at the first -touch of the sun melted away as swiftly as it had come. With it went the -surface moisture and an hour after sunrise the dust was once more rising -in clouds around us. - -We had no more than broken camp that morning when a merchant with a -pack-train passed us, and shouted above the bells of the leading animals -that we ought to hurry or we should get caught in the rain at the pass. -My guide, who, like many of his kind, had never before been over the -route he pretended to know, asked him in heaven's name what drink in -distant Camaná whence he had come produced such astonishing effects as -to make a man talk about rain in a parched desert. We all fell to -laughing and at our banter the stranger stopped his pack-train and -earnestly urged us to hurry, for, he said, the rains beyond the pass -were exceptionally heavy this year. We rode on in a doubtful state of -mind. I had heard about the rains, but I could not believe that they -fell in real showers! - -About noon the cloud bank darkened and overhung the border of the -desert. Still the sky above us was clear. Then happened what I can yet -scarcely believe. We rode into the head of a tiny valley that had cut -right across the coast chain. A wisp of cloud, an outlier of the main -bank, lay directly ahead of us. There were grass and bushes not a -half-mile below the bare dry spot on which we stood. We were riding down -toward them when of a sudden the wind freshened and the cloud wisp -enveloped us, shutting out the view, and ten minutes later the moisture -had gathered in little beads on the manes of our beasts and the trail -became slippery. In a half-hour it was raining and in an hour we were in -the midst of a heavy downpour. We stopped and pastured our famished -beasts in luxuriant clover. While they gorged themselves a herd of -cattle drifted along, and a startled band of burros that suddenly -confronted our beasts scampered out of sight in the heavy mist. Later we -passed a herdsman's hut and long before we reached him he shouted to us -to alter our course, for just ahead the old trail was wet and -treacherous at this time of year. The warning came too late. Several of -our beasts lost their footing and half rolled, half slid, down hill. One -turned completely over, pack and all, and lay in the soft mud calmly -taking advantage of the delay to pluck a few additional mouthfuls of -grass. We were glad to reach firmer ground on the other side of the -valley. - -The herdsmen were a hospitable lot. They had come from Camaná and rarely -saw travelers. Their single-roomed hut was mired so deeply that one -found it hard to decide whether to take shelter from the rain inside or -escape the mud by standing in the rain outside. They made a little -so-called cheese, rounded up and counted the cattle on clear days, -drove them to the springs from time to time, and talked incessantly of -the wretched rains in the hills and the delights of dry Camaná down on -the coast. We could not believe that only some hours' traveling -separated two localities so wholly unlike. - -The heavy showers and luxuriant pastures of the wet years and the light -local rains of the dry years endow the Coast Range with many peculiar -geographic qualities. The heavy rains provide the desert people at the -foot of the mountains such a wealth of pasture for their burdensome -stock as many oases dwellers possess only in their dreams. From near and -far cattle are driven to the wet hill meadows. Some are even brought in -from distant valleys by sea, yet only a very small part of the rich -pastures can be used. It is safe to say that they could comfortably -support ten times the number of cattle, mules, and burros that actually -graze upon them. The grass would be cut for export if the weather were -not so continually wet and if there were not so great a mixture of -weeds, flowers, and shrubs. - -Then come the dry years. The surplus stock is sold, and what remains is -always maintained at great expense. In 1907 I saw stock grazing in a -small patch of dried vegetation back of Mollendo, although they had to -be driven several miles to water. They looked as if they were surviving -with the greatest difficulty and their restless search for pasture was -like the search of a desperate hunter of game. In 1911 the same tract -was quite devoid of grass, and except for the contour-like trails that -completely covered the hills no one would even guess that this had -formerly been a cattle range. The same year, but five months later, a -carpet of grass, bathed in heavy mist, covered the soil; a trickle of -water had collected in pools on the valley floor; several happy families -from the town had laid out a prosperous-looking garden; there were -romping children who showed me where to pick up the trail to the port; -on every hand was life and activity because the rains had returned -bringing plenty in their train. I asked a native how often he was -prosperous. - -"Segun el temporal y la Providencia" (according to the weather and to -Providence), he replied, as he pointed significantly to the pretty green -hills crowned with gray mist. - -It, therefore, seems fortunate that the Coast Range is so placed as to -intercept and concentrate a part of the moisture that the sea-winds -carry, and doubly fortunate that its location is but a few miles from -the coast, thereby giving temporary relief to the relatively crowded -people of the lower irrigated valleys and the towns. The wet years -formerly developed a crop of prospectors. Pack animals are cheaper when -there is good pasture and they are also easier to maintain. So when the -rains came the hopeful pick-and-shovel amateurs began to emigrate from -the towns to search for ore among the discolored bands of rock intruded -into the granite masses of the coastal hills. However, the most likely -spots have been so thoroughly and so unsuccessfully prospected for many -years that there is no longer any interest in the "mines." - -Transportation rates are still most intimately related to the rains. My -guide had two prices--a high price if I proposed to enter a town at -night and thus require him to buy expensive forage; a low price if I -camped in the hills and reached the town in time for him to return to -the hills with his animals. Inquiry showed that this was the regular -custom. I also learned that in packing goods from one part of the coast -to another forage must be carried in dry years or the beasts required to -do without. In wet years by a very slight detour the packer has his -beasts in good pasture that is free for all. The merchant who dispatches -the goods may find his charges nearly doubled in extremely dry years. -Goods are more expensive and there is a decreased consumption. The -effects of the rains are thus transmitted from one to another, until at -last nearly all the members of a community are bearing a share of the -burdens imposed by drought. As always there are a few who prosper in -spite of the ill wind. If the pastures fail, live stock _must_ be sold -and the dealers ship south to the nitrate ports or north to the large -coast towns of Peru, where there is always a demand. Their business is -most active when it is dry or rather at the beginning, of the dry -period. Also if transport by land routes becomes too expensive the small -traders turn to the sea routes and the carriers have an increased -business. But so far as I have been able to learn, dry years favor only -a few scattered individuals. - -To the traveler on the west coast it is a source of constant surprise -that the sky is so often overcast and the ports hidden by fog, while on -every hand there are clear evidences of extreme aridity. Likewise it is -often inquired why the sunsets there should be often so superlatively -beautiful during the winter months when the coast is fog bound. Why a -desert when the air is so humid? Why striking sunsets when so many of -the days are marked by dull skies? As we have seen in the first part of -this chapter, the big desert tracts lie east of the Coast Range, and -there, excepting slight summer cloudiness, cloudless skies are the rule. -The desert just back of the coast is in many parts of Peru only a narrow -fringe of dry marine terraces quite unlike the real desert in type of -weather and in resources. The fog bank overhanging it forms over the -Humboldt Current which lies off shore; it drifts landward with the -onshore wind; it forms over the upwelling cold water between the current -and the shore; it gathers on the seaward slopes of the coastal hills as -the inflowing air ascends them in its journey eastward. Sometimes it -lies on the surface of the land and the water; more frequently it is -some distance above them. On many parts of the coast its characteristic -position is from 2,000 to 4,000 feet above sea level, descending at -night nearly or quite to the surface, ascending by day and sometimes all -but disappearing except as rain-clouds on the hills.[23] Upon the local -behavior of the fog bank depends in large measure the local climate. A -general description of the coastal climate will have many exceptions. -The physical principles involved are, however, the same everywhere. I -take for discussion therefore the case illustrated by Fig. 92, since -this also displays with reasonable fidelity the conditions along that -part of the Peruvian coast between Camaná and Mollendo which lies in the -field of work of the Yale Peruvian Expedition of 1911. - -Three typical positions of the fog bank are shown in the figure, and a -fourth--that in which the bank extends indefinitely westward--may be -supplied by the imagination. - -If the cloud bank be limited to _C_ only the early morning hours at the -port are cloudy. If it extend to _B_ the sun is obscured until midday. -If it reach as far west as _A_ only a few late afternoon hours are -sunny. Once in a while there is a sudden splash of rain--a few drops -which astonish the traveler who looks out upon a parched landscape. The -smaller drops are evaporated before reaching the earth. In spite of the -ever-present threat of rain the coast is extremely arid. Though the -vegetation appears to be dried and burned up, the air is humid and for -months the sky may be overcast most of the time. So nicely are the -rain-making conditions balanced that if one of our ordinary low-pressure -areas, or so-called cyclonic storms, from the temperate zone were set in -motion along the foot of the mountains, the resulting deluge would -immediately lay the coast in ruins. The cane-thatched, mud-walled huts -and houses would crumble in the heavy rain like a child's sand pile -before a rising sea; the alluvial valley land would be coated with -infertile gravel; and mighty rivers of sand, now delicately poised on -arid slopes, would inundate large tracts of fertile soil. - -[Illustration: FIG. 91--Looking down the canyon of the Majes River to -the edge of the cloud bank formed against the Coast Range back of -Camaná.] - -[Illustration: FIG. 92--Topographic and climatic cross-section to show -the varying positions of the cloud bank on the coast of Peru, the dry -terrace region, and the types of stream profiles in the various belts.] - -If the fog and cloud bank extend westward indefinitely, the entire day -may be overcast or the sun appear for a few moments only through -occasional rifts. Generally, also, it will make an appearance just -before sunset, its red disk completely filling the narrow space between -the under surface of the clouds and the water. I have repeatedly seen -the ship's passengers and even the crew leave the dinner table and -collect in wondering groups about the port-holes and doorways the better -to see the marvelous play of colors between sky and sea. It is -impossible not to be profoundly moved by so majestic a scene. A long -resplendent path of light upon the water is reflected in the clouds. -Each cloud margin is tinged with red and, as the sun sinks, the long -parallel bands of light are shortened westward, changing in color as -they go, until at last the full glory of the sunset is concentrated in a -blazing arc of reds, yellows, and purples, that to most people quite -atones for the dull gray day and its humid air. - -At times the clouds are broken up by the winds and scattered -helter-skelter through the west. A few of them may stray into the path -of the sun temporarily to hide it and to reflect its primary colors when -the sun reappears. From the main cloud masses there reach out slender -wind-blown streamers, each one delicately lighted as the sun's rays -filter through its minute water particles. Many streamers are visible -for only a short distance, but when the sun catches them their filmy -invisible fingers become delicate bands of light, some of which rapidly -grow out almost to the dome of the sky. Slowly they retreat and again -disappear as the rays of the sun are gradually shut off by the upturning -curve of the earth. - -The unequal distribution of precipitation in the climatic zones of -western Peru has important hydrographic consequences. These will now be -considered. In the preceding figure four types of stream profiles are -displayed and each has its particular relation to the cloud bank. Stream -1 is formed wholly upon the coastal terraces beneath the cloud bank. It -came into existence only after the uplift of the earth's crust that -brought the wave-cut platforms above sea level. It is extremely youthful -and on account first of the small seepage at its headquarters--it is -elsewhere wholly without a tributary water supply--and, second, of the -resistant granite that occurs along this part of the coast, it has very -steep and irregular walls and an ungraded floor. Many of these -"quebradas" are difficult to cross. A few of them have fences built -across their floors to prevent the escape of cattle and burros that -wander down from the grassy hills into the desert zone. Others are -partitioned off into corrals by stone fences, the steep walls of the -gorge preventing the escape of the cattle. To these are driven the -market cattle, or mules and burros that are required for relays along -the shore trail. - -Stream 2 heads in the belt of rains. Furthermore it is a much older -stream than 1, since it dates back to the time when the Coast Range was -first formed. It has ample tributary slopes and a large number of small -valleys. A trickle of water flows down to become lost in the alluvium of -the lower part of the valley or to reappear in scattered springs. Where -springs and seepage occur together, an olive grove or a garden marks the -spot, a corral or two and a mud or stone or reed hut is near by, and -there is a tiny oasis. Some of these dots of verdure become so dry -during a prolonged drought that the people, long-established, move away. -To others the people return periodically. Still others support permanent -settlements. - -Stream 3 has still greater age. Its only competitors are the feeble, -almost negligible, streams that at long intervals flow east toward the -dry zone. Hence it has cut back until it now heads in the desert. Its -widely branched tributaries gather moisture from large tracts. There is -running water in the valley floor even down in the terrace zone. At -least there are many dependable springs and the permanent homes that -they always encourage. A valley of this type is always marked by a -well-defined trail that leads from settlement to settlement and eastward -over the "pass" to the desert and the Andean towns. - -Stream 4 is a so-called "antecedent" stream. It existed before the Coast -Range was uplifted and cut its channel downward as the mountains rose in -its path. The stretch where it crosses the mountains may be a canyon -with a narrow, rocky, and uncultivable floor, so that the valley trails -rise to a pass like that at the head of stream 3, and descend again to -the settlements at the mouth of 4. There is in this last type an -abundance of water, for the sources of the stream are in the zone of -permanent snows and frequent winter rains of the lofty Cordillera of the -Andes. The settlements along this stream are continuous, except where -shut-ins occur--narrow, rocky defiles caused by more resistant rock -masses in the path of the stream. Here and there are villages. The -streams have fish. When the water rises the river may be unfordable and -people on opposite sides must resort to boats or rafts.[24] - - -EASTERN BORDER CLIMATES - -On windward mountain slopes there is always a belt of maximum -precipitation whose elevation and width vary with the strength of the -wind, with the temperature, and with the topography. A strong and -constant wind will produce a much more marked concentration of the -rainfall. The belt is at a low elevation in high latitudes and at a high -elevation in low latitudes, with many irregularities of position -dependent upon the local and especially the minimum winter temperature. -The topographic controls are important, since the rain-compelling -elevation may scatter widely the localities of maximum precipitation or -concentrate them within extremely narrow limits. The human effects of -these climatic conditions are manifold. Wherever the heaviest rains are, -there, too, as a rule, are the densest forests and often the most -valuable kinds of trees. If the general climate be favorable and the -region lie near dense and advanced populations, exploitation of the -forest and progress of the people will go hand in hand. If the region be -remote and some or all of the people in a primitive state, the forest -may hinder communication and retard development, especially if it lie in -a hot zone where the natural growth of population is slow.... These are -some of the considerations we shall keep in mind while investigating the -climate of the eastern border of the Peruvian Andes. - -[Illustration: FIG. 93A--Cloud types and rainfall belts on the eastern -border of the Peruvian Andes in the dry season, southern winter. The -zone of maximum rainfall extends approximately from 4,000 to 10,000 feet -elevation.] - -[Illustration: FIG. 93B--Cloud types and rainfall belts on the eastern -border of the Peruvian Andes in the wet season, southern summer.] - -The belt of maximum precipitation on the eastern border of the Andean -Cordillera in Peru lies between 4,000 and 10,000 feet. Judging by the -temporary records of the expedition and especially by the types of -forest growth, the heaviest rains occur around 8,000 feet. It is between -these elevations that the densest part of the Peruvian _montaña_ -(forest) is found. The cold timber line is at 10,500 feet with -exceptional extensions of a few species to 12,500 feet. In basins or -deep secluded valleys near the mountain border, a dry timber line occurs -at 3,000 feet with many variations in elevation due to the variable -declivity and exposure of the slopes and degree of seclusion of the -valleys. Elsewhere, the mountain forest passes without a break into the -plains forest with change in type but with little change in density. The -procumbent and suppressed trees of the cold timber line in regions of -heavy winter snows are here absent, for the snows rarely reach below -14,000 feet and even at that elevation they are only light and -temporary. The line of perpetual snow is at 15,000 feet. This permanent -gap of several thousand feet vertical elevation between the zone of snow -and the zone of forest permits the full extension of many pioneer forest -species, which is to say, there is an irregular development of the cold -timber line. It also permits the full use of the pasture belt above the -timber (Fig. 97), hence permanent habitations exist but little below the -snowline and a group of distinctive high-mountain folk enjoys a wide -distribution. There is a seasonal migration here, but it is not -wholesale; there are pastures snow-covered in the southern winter, but, -instead of the complete winter burial of the Alpine meadows of our -western mountains, we have here only a buried upper fringe. All the rest -of the pasture belt is open for stock the year round. - -This climatic distinction between the lofty grazing lands of the tropics -and those of the temperate zones is far-reaching. Our mountain forests -are not utilized from above but from below. Furthermore, the chief ways -of communication lead around our forests, or, if through them, only for -the purpose of putting one population group in closer touch with -another. In the Peruvian Andes the largest population groups live above -the forest, not below it or within it. It must be and is exploited from -above. - -Hence railways to the eastern valleys of Peru have two chief objects, -(1) to get the plantation product to the dense populations above the -forest and (2) to bring timber from the _montaña_ to the treeless -plateau. The mountain prospector is always near a habitation; the rubber -prospector goes down into the forested valleys and plains far from -habitations. The forest separates the navigable streams from the chief -towns of the plateau; it does not lead down to rich and densely -populated valley floors. - -Students in eastern Peru should find it a little difficult to understand -poetical allusions to silent and lonely highlands in contrast to the -busy life of the valleys. To them Shelley's description of the view from -the Euganean Hills of northern Italy, - - "Beneath is spread like a green sea - The waveless plain of Lombardy, ... - Islanded by cities fair," - -might well seem to refer to a world that is upside down. - -There is much variation in the forest types between the mountains and -the plains. At the top of the forest zone the warm sunny slopes have a -forest cover; the shady slopes are treeless. At the lower edge of the -grassland, only the shady slopes are forested (Fig. 53B). Cacti of -arboreal size and form grow on the lofty mountains far above the limits -of the true forest; they also appear at 3,000 feet in modified form, -large, rank, soft-spined, and in dense stands on the semi-arid valley -floors below the dry timber line. Large tracts between 8,000 and 10,000 -feet are covered with a forest growth distributed by species--here a -dense stand of one type of tree, there another. This is the most -accessible part of the Peruvian forest and along the larger valleys it -is utilized to some extent. The number of species is more limited, -however, and the best timber trees are lower down. Though often referred -to as jungle, the lowlier growths at the upper edge of the forest zone -have no resemblance to the true jungle that crowds the lowland forest. -They are merely an undergrowth, generally open, though in some places -dense. They are nowhere more dense than many examples from New England -or the West. - -Where deep valleys occur near the border of the mountains there is a -semi-arid climate below and a wet climate above, with a correspondingly -greater number of species within short distances of each other. This is -a far more varied forest than at the upper edge of the timber zone or -down on the monotonous plains. It has a higher intrinsic value than any -other. That part of it between the Pongo and Yavero (1,200 to 4,000 -feet) is very beautiful, with little undergrowth except a light -ground-cover of ferns. The trees are from 40 to 100 feet in height with -an average diameter of about 15 inches. It would yield from 3,000 to -5,000 board feet per acre exclusive of the palms. There are very few -vines suspended from the forest crown and the trunks run clear from 30 -to 60 feet above the ground. Were there plenty of labor and a good -transportation line, these stands would have high economic value. Among -the most noteworthy trees are the soft white cedar, strong and light; -the amarillo and the sumbayllo, very durable in water; the black nogal, -and the black balsam, straight and easy to work; the heavy yunquero, -which turns pink when dry; the chunta or black palm, so hard and -straight and easy to split that wooden nails are made from it; and the -rarer sandy matico, highly prized for dug-out canoes. Also from the -chunta palm, hollow except for a few central fibers, easily removed, -pipes are made to convey water. The cocobolo has a rich brown color and -a glossy surface and is very rare, hence is much sought after for use in -furniture making. Most of these woods take a brilliant polish and -exhibit a richness and depth of color and a beauty of grain that are -rare among our northern woods. - -[Illustration: FIG. 94--Cloud belt at 11,000 feet in the Apurimac Canyon -near Incahuasi. For a regional diagram and a climatic cross-section see -Figs. 32 and 33.] - -[Illustration: FIG. 95--The tropical forest near Pabellon on the slopes -of the Urubamba Valley. Elevation 3,000 feet (915 m.).] - -The plains forest northeast of the mountains is in the zone of moderate -rainfall where there is one long dry season and one long wet season. -When it is dry the daytime temperatures rise rapidly to such high levels -that the relative humidity of the air falls below 50 per cent (Fig. -110). The effect on the vegetation is so marked that many plants pass -into a distinctly wilted condition. On clear days the rapid fall in the -relative humidity is astonishing. By contrast the air on the mountain -border heats more slowly and has a higher relative humidity, because -clouds form almost constantly in the ascending air currents and reflect -and absorb a large part of the heat of the sun's rays. It is striking to -find large tracts of cane and bamboo on the sand bars and on wet shady -hillslopes in the slope belt, and to pass out of them in going to the -plains with which we generally associate a swamp vegetation. They exist -on the plains, but only in favored, that is to say wet, spots. Larger -and more typical tracts grow farther north where the heavier rains of -the Amazon basin fall. - -The floods of the wet tropical season also have a restricting influence -upon the tropical forest. They deliver such vast quantities of water to -the low-gradient lowland streams that the plains rivers double, even -treble, their width and huge pools and even temporary lakes form in the -shallow depressions back of the natural levees. Of trees in the flooded -areas there are only those few species that can grow standing in water -several months each year. There are also cane and bamboo, ferns in -unlimited numbers, and a dense growth of jungle. These are the haunts of -the peccary, the red forest deer, and the jungle cat. Except along the -narrow and tortuous animal trails the country is quite impassable. Thus -for the sturdiest and most useful forest growth the one-wet-one-dry -season zone of the plains has alternately too much and too little water. -The rubber tree is most tolerant toward these conditions. Some of the -best stands of rubber trees in Amazonia are in the southwestern part of -the basin of eastern Peru and Bolivia, where there is the most typical -development of the habitat marked by the seasonal alternation of floods -and high temperatures. - -When tropical agriculture is extended to the plains the long dry season -will be found greatly to favor it. The southwestern quadrant of the -Amazon basin, above referred to, is the best agricultural area within -it. The northern limits of the tract are only a little beyond the Pongo. -Thence northward the climate becomes wetter. Indeed the best tracts of -all extend from Bolivia only a little way into southeastern Peru, and -are coincident with the patchy grasslands that are there interspersed -with belts of woodland and forest. Sugar-cane is favored by a climate -that permits rapid growth with a heavy rainfall and a dry season is -required for quality and for the harvest. Rice and a multitude of -vegetable crops are also well suited to this type of climate. Even corn -can be grown in large quantities. - -At the present time tropical agriculture is almost wholly confined to -the mountain valleys. The reasons are not wholly climatic, as the above -enumeration of the advantages of the plains suggests. The consuming -centers are on the plateau toward the west and limitation to mule pack -transport always makes distance in a rough country a very serious -problem. The valleys combine with the advantage of a short haul a -climate astonishingly like the one just described. In fact it is even -more extreme in its seasonal contrasts. The explanation is dependent -upon precisely the same principles we have hitherto employed. The front -range of the Andes and the course of the Urubamba run parallel for some -distance. Further, the front range is in many places somewhat higher -than the mountain spurs and knobs directly behind it. Even when these -relations are reversed the front range still acts as a barrier to the -rains for all the deep valleys behind it whose courses are not directly -toward the plains. Thus, one of the largest valleys in Peru, the -Urubamba, drops to 3,400 feet at Santa Ana and to 2,000 feet at -Rosalina, well within the eastern scarp of the Andes. The mountains -immediately about it are from 6,000 to 10,000 feet high. The result is a -deep semi-arid pocket with only a patchy forest (Fig. 54, p. 79).[25] In -places the degree of seclusion from the wind is so great that the scrub, -cacti, and irrigation remind one strongly of the desert on the border of -an oasis, only here the transition is toward forests instead of barren -wastes. The dense forest, or _montaña_, grows in the zone of clouds and -maximum precipitation between 4,000 and 10,000 feet. At the lower limit -it descends a thousand feet farther on shady slopes than it does on -sunny slopes. The continuous forest is so closely restricted to the -cloud belt that in Fig. 99 the two limits may be seen in one photograph. -All these sharply defined limits and contrasts are due to the fact that -the broad valley, discharging through a narrow and remote gorge, is -really to leeward of all the mountains around it. It is like a real -desert basin except in a lesser degree of exclusion from the rains. If -it were narrow and small the rains formed on the surrounding heights -would be carried over into it. Rain on the hills and sunshine in the -valley is actually the day-by-day weather of the dry season. In the wet -season the sky is overcast, the rains are general, though lighter in the -valley pocket, and plants there have then their season of most rapid -growth. The dry season brings plants to maturity and is the time of -harvest. Hence sugar and cacao plantations on a large scale, hence a -varied life in a restricted area, hence a distinct geographic province -unique in South America. - - -INTER-ANDEAN VALLEY CLIMATES - -Not all the deep Andean valleys lie on or near the eastern border. Some, -like the Apurimac and the Marañon, extend well into the interior of the -Cordillera. Besides these deep remote valleys with their distinct -climatic belts are basins, most of them with outlets to the sea--broad -structural depressions occurring in some cases along large and in others -along small drainage lines. The Cuzco basin at 11,000 feet and the -Abancay basin at 6,000 to 8,000 feet are typical. Both have abrupt -borders, narrow outlets, large bordering alluvial fans, and fertile -irrigable soil. Their difference of elevation occurs at a critical -level. Corn will ripen in the Cuzco basin, but cane will not. Barley, -wheat, and potatoes are the staple crops in the one; sugar-cane, -alfalfa, and fruit in the other. Since both are bordered by high -pastures and by mineralized rocks, the deeper Abancay basin is more -varied. If it were not so difficult to get its products to market by -reason of its inaccessibility, the Abancay basin would be the more -important. In both areas there is less rainfall on the basin floor than -on the surrounding hills and mountains, and irrigation is practised, but -the deeper drier basin is the more dependent upon it. Many small high -basins are only within the limits of potato cultivation. They also -receive proportionately more rain. Hence irrigation is unnecessary. -According as the various basins take in one or another of the different -product levels (Fig. 35) their life is meager and unimportant or rich -and interesting. - -The deep-valley type of climate has the basin factors more strongly -developed. Below the Canyon of Choqquequirau, a topographic feature -comparable with the Canyon of Torontoy, the Apurimac descends to 3,000 -feet, broadens to several miles, and has large alluvial fans built into -it. Its floor is really arid, with naked gravel and rock, cacti stands, -and gnarled shrubs as the chief elements of the landscape. Moreover the -lower part of the valley is the steeper. A former erosion level is -indicated in Fig. 125. When it was in existence the slopes were more -moderate than now and the valley broad and open. Thereupon came uplift -and the incision of the stream to its present level. As a result, a -steep canyon was cut in the floor of a mature valley. Hence the slopes -are in a relation unlike that of most of the slopes in our most familiar -landscapes. The gentle slopes are above, the steep below. The break -between the two, a topographic unconformity, may be distinctly traced. - -[Illustration: FIG. 96--Snow-capped mountain, Soiroccocha, north of -Arma, Cordillera Vilcapampa. The blue glacier ice descends almost to the -edge of a belt of extraordinary woodland growing just under the -snowline. The glacier is seen to overhang the valley and to have built -on the steep valley wall terminal moraines whose outer slopes are almost -precipitous.] - -[Illustration: FIG. 97--Shrubby vegetation mixed with grass at 14,000 -feet (4,270 m.) on the northern or sunny slopes of the Cordillera -Vilcapampa above Pampaconas, a thousand feet below the snowline. The -grass is remarkably profuse and supports the flocks and herds of a -pastoral population.] - -[Illustration: FIG. 98--Dense ground cover, typical trees, epiphytes, -and parasites of the tropical rain forest at 2,500-3,000 feet between -Pongo de Mainique and Rosalina.] - -[Illustration: FIG. 99--The Urubamba Valley below Santa Ana. On the dry -valley floor is a mixed growth of scattered trees, shrubs and grass, -with shrubs predominating. Higher up a more luxuriant ravine vegetation -appears. On the upper spurs true forest patches occupy the shady slopes. -Finally, in the zone of clouds at the top of the picture is a continuous -forest. See Fig. 17, for regional applications.] - -Combined with these topographic features are certain climatic features -of equal precision. Between 7,000 and 13,000 feet is a zone of clouds -oftentimes marked out as distinctly as the belt of fog on the Peruvian -coast.[26] Rarely does it extend across the valley. Generally it hangs -as a white belt on the opposite walls. When the up-valley winds of day -begin to blow it drifts up-valley, oftentimes to be dissolved as it -strikes the warmer slopes of the upper valley, just as its settling -under surface is constantly being dissolved in the warm dry air of the -valley floor. Where the precipitation is heaviest there is a belt of -woodland--dark, twisted trees, moss-draped, wet--a Druid forest. Below -and above the woodland are grassy slopes. At Incahuasi a spur runs out -and down until at last it terminates between two deep canyons. No -ordinary wells could be successful. The ground water must be a thousand -feet down, so a canal, a tiny thing only a few inches wide and deep, has -been cut away up to a woodland stream. Thence the water is carried down -by a contour-like course out of the woodland into the pasture, and so -down to the narrow part of the spur where there is pasture but no -springs or streams. - -Corn fields surround the few scattered habitations that have been built -just above the break or shoulder on the valley wall where the woodland -terminates, and there are fine grazing lands. The trails follow the -upper slopes whose gentler contours permit a certain liberty of -movement. Then the way plunges downward over a staircase trail, over -steep boulder-strewn slopes to the arid floor of a tributary where -nature has built a graded route. And so to the still more arid floor of -the main valley, where the ample and moderate slopes of the alluvial -fans with their mountain streams permit plantation agriculture again to -come in. - -To these three climates, the western border type, the eastern border -type, and the inter-Andean type, we have given chief attention because -they have the most important human relations. The statistical records of -the expedition as shown in the curves and the discussion that -accompanies them give attention to those climatic features that are of -theoretical rather than practical interest, and are largely concerned -with the conventional expression of the facts of weather and climate. -They are therefore combined in the following chapter which is devoted -chiefly to a technical discussion of the meteorology as distinguished -from the climatology of the Peruvian Andes. - - - - -CHAPTER X - -METEOROLOGICAL RECORDS FROM THE PERUVIAN ANDES - - -INTRODUCTION - -The data in this chapter, on the weather and climate of the Peruvian -Andes, were gathered under the usual difficulties that accompany the -collection of records at camps scarcely ever pitched at the same -elevation or with the same exposure two days in succession. Some of -them, and I may add, the best, were contributed by volunteer observers -at fixed stations. The observations are not confined to the field of the -Yale Peruvian Expedition of 1911, but include also observations from -Professor Hiram Bingham's Expeditions of 1912 and 1914-15, together with -data from the Yale South American Expedition of 1907. In addition I have -used observations supplied by the Morococha Mining Company through J. P. -Little. Some hitherto unpublished observations from Cochabamba, Bolivia, -gathered by Herr Krüger at considerable expense of money for instruments -and of time from a large business, are also included, and he deserves -the more credit for his generous gift of these data since they were -collected for scientific purposes only and not in connection with -enterprises in which they might be of pecuniary value. My only excuse to -Herr Krüger for this long delay in publication (they were put into my -hands in 1907) is that I have wanted to publish his data in a dignified -form and also to use them for comparison with the data of other climatic -provinces. - -A further word to the reader seems necessary before he examines the -following curves and tables. It would be somewhat audacious to assume -that these short-term records have far-reaching importance. Much of -their value lies in their organization with respect to the data already -published on the climate of Peru. But since this would require a delay -of several years in their publication it seems better to present them -now in their simplest form. After all, the professional climatologist, -to whom they are chiefly of interest, scarcely needs to have such -organization supplied to him. Then, too, we hope that there will become -available in the next ten or fifteen years a vastly larger body of -climatological facts from this region. When these have been collected we -may look forward to a volume or a series of volumes on the "Climate of -Peru," with full statistical tables and a complete discussion of them. -That would seem to be the best time for the reproduction of the detailed -statistics now on hand. It is only necessary that there shall be -sufficient analysis of the data from time to time to give a general idea -of their character and to indicate in what way the scope of the -observations might profitably be extended. I have, therefore, taken from -the available facts only such as seem to me of the most importance -because of their unusual character or their special relations to the -boundaries of plant provinces or of the so-called "natural regions" of -geography. - - -MACHU PICCHU[27] - -The following observations are of special interest in that they -illustrate the weather during the southern winter and spring at the -famous ruins of Machu Picchu in the Canyon of Torontoy. The elevation is -8,500 feet. The period they cover is too short to give more than a hint -of the climate or of the weather for the year. It extends from August -20, 1912, to November 6, 1912 (79 days). - - ANALYTICAL TABLE OF WIND DIRECTIONS, MACHU PICCHU, 1912 - - -----------+--------------------------------------------------------+ - | Number of Observations | - Direction +----------------------------+---------------------------| - of wind | Aug. 20 -- Sept. 30 | Oct. 1 -- Nov. 6 | - | 7 a. m. 1 p. m. 7 p. m. | 7 a. m. 1 p. m. 7 p. m. | - -----------+----------------------------+---------------------------+ - N. | 5 2 5 | 2 -- -- | - N.W. | 9 10 14 | 4 6 11 | - W. | -- 1 2 | 2 2 4 | - S. W. | -- -- 1 | 1 1 6 | - S. | -- -- 1 | -- -- 2 | - S. E. | 4 2 1 | -- -- 3 | - E. | 6 3 3 | 12 4 4 | - N. E. | 8 7 6 | 4 1 3 | - CALM | -- -- 2 | 5 3 3 | - -----------+----------------------------+---------------------------+ - - ----------------------------------------------------------------+ - | Percentages of Total Observation[28] | - Direction|------------------------------------------------------| - of wind | Aug. 20 ---- Sept. 30 | Oct. 1 ---- Nov. 6 | - | 7 a. m. 1 p.m. 7 p. m. | 7 a. m. 1 p. m. 7 p. m.| - ----------------------------------------------------------------| - N. | 15.6 8.0 14.2 | 6.7 ---- ---- | - N. W. | 28.1 40.0 40.0 | 13.3 35.3 30.7 | - W. | ---- 4.0 5.7 | 6.7 11.8 11.1 | - S. W. | ---- ---- 2.8 | 3.3 5.9 16.7 | - S. | ---- ---- 2.8 | ---- ---- 5.5 | - S. E. | 12.5 8.0 2.8 | ---- ---- 8.3 | - E. | 18.8 12.0 8.6 | 40.0 23.5 11.1 | - N. E. | 25.0 28.0 17.1 | 13.3 5.9 8.3 | - CALM | ---- ---- 5.7 | 16.7 17.6 8.3 | - ----------------------------------------------------------------+ - -[Illustration: FIG. 100--Wind roses for Machu Picchu, August 20 to -November 6, 1912.] - -The high percentage of northwest winds during afternoon hours is due to -the up-valley movement of the air common to almost all mountain borders. -The air over a mountain slope is heated more than the free air at the -same elevation over the plains (or lower valley); hence a barometric -gradient towards the mountain becomes established. At Machu Picchu the -Canyon of Torontoy trends northwest, making there a sharp turn from an -equally sharp northeast bend directly upstream. The easterly components -are unrelated to the topography. They represent the trades. If a wind -rose were made for still earlier morning hours these winds would be more -faithfully represented. That an easterly and northeasterly rather than a -southeasterly direction should be assumed by the trades is not difficult -to believe when we consider the trend of the Cordillera--southeast to -northwest. The observations from here down to the plains all show that -there is a distinct change in wind direction in sympathy with the larger -features of the topography, especially the deep valleys and canyons, the -trades coming in from the northeast. - - -CLOUDINESS - -It will be seen that the sky was overcast or a fog lay in the valley 53 -per cent of the time at early morning hours. Even at noon the sky was at -no time clear, and it was more than 50 per cent clear only 18 per cent -of the time. Yet this is the so-called "dry" season of the valleys of -the eastern Andes. The rainfall record is in close sympathy. In the 79 -days' observations rain is recorded on 50 days with a greater proportion -from mid-September to the end of the period (November 6), a distinct -transition toward the wet period that extends from December to May. The -approximate distribution of the rains by hours of observation (7 A. M., -1 P. M., 7 P. M.) was in the ratio 4:3:6. Also the greatest number of -heavy showers as well as the greatest number of showers took place in -the evening. The rainfall was apparently unrelated to wind direction in -the immediate locality, though undoubtedly associated with the regional -movement of the moist plains air toward the mountains. All these facts -regarding clouds and rain plainly show the location of the place in the -belt of maximum precipitation. There is, therefore, a heavy cover of -vegetation. While the situation is admirable for defence, the murky -skies and frequent fogs somewhat offset its topographic surroundings as -a lookout. - - ANALYTICAL TABLE OF THE STATE OF THE SKY, MACHU PICCHU, 1912 - - ---------------+-------------+-------------+ - | Morning | Total | - ---------------+------+------+------+------+ - |Aug.- |Oct.- |Days | % | - |Sept. |Nov. | | | - ---------------+------+------+------+------+ - Foggy | 3.0 | 14.0 | 17.0 | 28.4 | - Overcast | 12.0 | 3.0 | 15.0 | 25.0 | - 50-100% cloudy | 4.0 | 10.0 | 14.0 | 23.3 | - 0-50% cloudy | 6.0 | 4.0 | 10.0 | 16.7 | - Clear | 3.0 | 1.0 | 4.0 | 6.6 | - ---------------+------+------+------+------+ - - ---------------+-------------+-------------+ - | Noon | Total | - ---------------+------+------+------+------+ - |Aug.- |Oct.- | Days | % | - |Sept. |Nov. | | | - ---------------+------+------+------+------+ - Foggy | 1.0 | -- | 1.0 | 2.6 | - Overcast | 6.0 | 8.0 | 14.0 | 36.8 | - 50-100% cloudy | 0.0 | 7.0 | 16.0 | 42.2 | - 0-50% cloudy | 5.0 | 2.0 | 7.0 | 18.4 | - Clear | 0.0 | 0.0 | 0.0 | 0.0 | - ---------------+------+------+------+------+ - - ---------------+-------------+------------- - | Evening | Total - ---------------+------+------+------+------ - |Aug.- |Oct.- |Days | % - |Sept. |Nov. | | - ---------------+------+------+------+------ - Foggy | 1.0 | 2.0 | 3.0 | 4.3 - Overcast | 13.0 | 11.0 | 24.0 | 34.8 - 50-100% cloudy | 8.0 | 15.0 | 23.0 | 33.3 - 0-50% cloudy | 9.0 | 4.0 | 13.0 | 18.8 - Clear | 3.0 | 3.0 | 6.0 | 8.8 - ---------------+------+------+------+------ - - -SANTA LUCIA[29] - -Santa Lucia is a mining center in the province of Puno (16° S.), at the -head of a valley here running northeast towards Lake Titicaca. Its -elevation, 15,500 feet above sea level, confers on it unusual interest -as a meteorological station. A thermograph has been installed which -enables a closer study of the temperature to be made than in the case of -the other stations. It is unfortunate, however, that the observations -upon clouds, wind directions, etc., should not have been taken at -regular hours. The time ranges from 8.30 to 11.30 for morning hours and -from 2.30 to 5.30 for afternoon. The observations cover portions of the -years 1913 and 1914. - - -TEMPERATURE - -Perhaps the most striking features of the weather of Santa Lucia are the -highly regular changes of temperature from night to day or the uniformly -great diurnal range and the small differences of temperature from day to -day or the low diurnal variability. For the whole period of nearly a -year the diurnal variability never exceeds 9.5° F. (5.3° C.) and for -days at a time it does not exceed 2-3° F. (1.1°-1.7° C.). The most -frequent variation, occurring on 71 per cent of the total number of -days, is from 0-3° F., and the mean for the year gives the low -variability of 1.9° F. (1.06° C.). These facts, illustrative of a type -of weather comparable in _uniformity_ with low stations on the Amazon -plains, are shown in the table following as well as in the accompanying -curves. - - FREQUENCY OF THE DIURNAL VARIABILITY, SANTA LUCIA, 1913-14 - - ----------+----+----+----+----+-----+ - | | | | | | - Degrees F.|May |June|July|Aug.|Sept.| - ----------+----+----+----+----+-----+ - 0 | -- | 2 | 6 | 3 | 4 | - 0-1 | 2 | 7 | 7 | 5 | 6 | - 1-2 | 11 | 5 | 7 | 11 | 7 | - 2-3 | 2 | 8 | 8 | 9 | 3 | - 3-4 | 4 | 4 | 2 | 1 | 4 | - 4-5 | 1 | 3 | 1 | -- | 2 | - Over 5 | -- | 1 | -- | 2 | 4 | - ----------+----+----+----+----+-----+ - Days per| 20 | 30 | 31 | 31 | 30 | - month| | | | | | - ----------+----+----+----+----+-----+ - - ----------+----+----+----+----+----+-----++--------- - | | | | | | ||Total No. - Degrees F.|Oct.|Nov.|Dec.|Jan.|Feb.|March||of days - ----------+----+----+----+----+----+-----++--------- - 0 | 6 | 2 | -- | 1 | -- | 2 || 26 - 0-1 | 4 | 8 | 12 | 14 | 9 | 5 || 79 - 1-2 | 8 | 5 | 5 | 4 | 9 | 13 || 85 - 2-3 | 7 | 7 | 5 | 5 | 4 | 6 || 64 - 3-4 | 1 | 3 | 6 | 2 | 4 | 2 || 33 - 4-5 | 1 | 3 | -- | 2 | 1 | 1 || 15 - Over 5 | 4 | 2 | 2 | 3 | 1 | -- || 19 - ----------+----+----+----+----+----+-----++--------- - Days per| 31 | 30 | 30 | 31 | 28 | 29 || 321 - month| | | | | | || - ----------+----+----+----+----+----+-----++--------- - -If we take the means of the diurnal variations by months we have a still -more striking curve showing how little change there is between -successive days. June and December are marked by humps in the curve. -They are the months of extreme weather when for several weeks the -temperatures drop to their lowest or climb to their highest levels. -Moreover, there is at these lofty stations no pronounced lag of the -maximum and minimum temperatures for the year behind the times of -greatest and least heating such as we have at lower levels in the -temperate zone. Thus we have the highest temperature for the year on -December 2, 70.4° F. (21.3° C.), the lowest on June 3, 0.2° F. (--17.7° -C.). The daily maxima and minima have the same characteristic. Radiation -is active in the thin air of high stations and there is a very direct -relation between the times of greatest heat received and greatest heat -contained. The process is seen at its best immediately after the sun is -obscured by clouds. In five minutes I have observed the temperature drop -20° F. (11.1° C.) at 16,000 feet (4,877 m.); and a drop of 10° F. (5.6° -C.) is common anywhere above 14,000 feet (4,267 m.). In the curves of -daily maximum and minimum temperatures we have clearly brought out the -uniformity with which the maxima of high-level stations rise to a mean -level during the winter months (May-August). Only at long intervals is -there a short series of cloudy days when the maximum is 10°-12° F. -(5.6°-6.7° C.) below the normal and the minimum stands at abnormally -high levels. Since clouds form at night in quite variable amounts--in -contrast to the nearly cloudless days--there is a far greater -variability among the minimum temperatures. Indeed the variability of -the winter minima is greater than that of the summer minima, for at the -latter season the nightly cloud cover imposes much more stable -atmospheric temperatures. The summer maxima have a greater degree of -variability. Several clear days in succession allow the temperature to -rise from 5°-10° F. (2.8°-5.6° C.) above the winter maxima. But such -extremes are rather strictly confined to the height of the summer -season--December and January. For the rest of the summer the maxima rise -only a few degrees above those of the winter. This feature of the -climate combines with a December maximum of rainfall to limit the period -of most rapid plant growth to two months. Barley sown in late November -could scarcely mature by the end of January, even if growing on the -Argentine plains and much less at an elevation which carries the night -temperatures below freezing at least once a week and where the mean -temperature hovers about 47° F. (8.3° C.). The proper conditions for -barley growing are not encountered above 13,000 to 13,500 feet and the -farmer cannot be certain that it will ripen above 12,500 feet in the -latitude of Santa Lucia. - -The curve of mean monthly temperatures expresses a fact of great -importance in the plant growth at high situations in the Andes--the -sharp break between the winter and summer seasons. There are no real -spring and autumn seasons. This is especially well shown in the curve -for non-periodic mean monthly range of temperature for the month of -October. During the half of the year that the sun is in the southern -hemisphere the sun's noonday rays strike Santa Lucia at an angle that -varies between 0° and 16° from the vertical. The days and nights are of -almost equal length and though there is rapid radiation at night there -is also rapid insolation by day. When the sun is in the northern -hemisphere the days are shortened from one to two hours and the angle of -insolation decreased, whence the total amount of heat received is so -diminished that the mean monthly temperature lies only a little above -freezing point. In winter the quiet pools beside the springs freeze over -long before dark as the hill shadows grow down into the high-level -valleys, and by morning ice also covers the brooks and marshes. Yet the -sun and wind-cured _ichu_ grass lives here, pale green in summer, -straw-yellow in winter. The tola bush also grows rather abundantly. But -we are almost at the upper limit of the finer grasses and a few hundred -feet higher carries one into the realm of the snowline vegetation, -mosses and lichens and a few sturdy flowering plants. - -For convenience in future comparative studies the absolute extremes are -arranged in the following table: - -[Illustration: FIG. 101 A--DIURNAL TEMPERATURE, SANTA LUCIA, 1913-'14 -C--DIURNAL RANGE OF TEMPERATURE, SANTA LUCIA, 1913-'14 E--DIURNAL -VARIABILITY OF TEMPERATURE, SANTA LUCIA, 1913-'14 B--MEAN MONTHLY -TEMPERATURE, SANTA LUCIA, 1913-'14 D--MONTHLY MEANS OF DIURNAL RANGE OF -TEMPERATURE, SANTA LUCIA, 1913-'14 F--RELATIVE HUMIDITY, SANTA LUCIA, -1913-'14] - - ABSOLUTE MONTHLY EXTREMES, SANTA LUCIA, 1913-14 - - -----------------------+----------++----------+---------------- - Date | Highest || Lowest | Date - -----------------------+----------++----------+---------------- - May[30] (12) | 62° F. || 9° F. | May (25, 26) - June (4 days) | 60° F. || 0.2° F. | June (3) - July (4 days, 31) | 60° F. || 5° F. | July (8) - Aug. (8, 26) | 62° F. || 4° F. | Aug. (4, 5) - Sept. (several days) | 62° F. || 7° F. | Sept. (4 days) - Oct. (24) | 63° F. || 10° F. | Oct. (12, 13) - Nov. (11)[31] | 63° F. || 24.0° F. | Nov. (29) - Dec. (2) | 70.4° F. || 22.2° F. | Dec. (14) - Jan. (19) | 69.5° F. || 26.5° F. | Jan. (3, 15) - Feb. (16, 18) | 63.2° F. || 30.5° F. | Feb. (23) - March (8) | 68.4° F. || 28.5° F. | March (6) - -----------------------+----------++----------+---------------- - - -RAINFALL - -The rainfall record for Santa Lucia is for the year beginning November, -1913. For this period the precipitation amounts to 24.9 inches of which -over 85 per cent fell in the rainy season from November to March. Most -of the rain fell during the violent afternoon tempests that characterize -the summer of these high altitudes. - -The rainfall of Santa Lucia for this first year of record approximates -closely to the yearly mean of 23.8 inches for the station of Caylloma in -the adjacent province of that name. Caylloma is the center of a mining -district essentially similar to Santa Lucia though the elevation of its -meteorological station, 14,196 feet (4,330 m.), is lower. It is one of -the few Peruvian stations for which a comparatively long series of -records is available. The _Boletín de la Sociedad Geográfica de -Lima_[32] contains a résumé of rainfall and temperature for seven years, -1896-7 to 1902-3. Later data may be found in subsequent volumes of the -same publication but they have not been summarized or in any way -prepared for analysis and they contain several typographical errors. A -graphic representation of the monthly rainfall for the earlier period is -here reproduced from the _Boletín de minas del Perú_.[33] The amount -of precipitation fluctuates considerably from year to year. For the -earlier period, with a mean of 23.8 inches the minimum (1896-7) was 8 -inches and the maximum (1898-9) 36 inches. For the later period, 1903-4 -to 1910-11, with a mean of 29.5 inches the minimum (1904-5) was 17.5 -inches and the maximum (1906-7) was 43 inches. - -[Illustration: FIG. 102--Monthly rainfall of Santa Lucia for the year -November, 1913, to October, 1914. No rain fell in July and August.] - -[Illustration: FIG. 103A--Maximum, mean and minimum monthly rainfall of -Caylloma for the period 1896-7 to 1902-3. July was absolutely rainless. -Caylloma is situated immediately east of the crest of the Maritime -Cordillera in a position similar to that of Santa Lucia (see Fig. 66).] - -[Illustration: FIG. 103B--Annual rainfall of Caylloma for the periods -1896-7 to 1902-3; 1903-4 to 1910-11 and for 1915-6 (incomplete: May and -June, months of low rainfall, are missing). Means for the respective -seven and eight year periods are shown and the rainfall of Santa Lucia -for the single observation year is inserted for comparison.] - - RAINFALL, SANTA LUCIA, NOV. 1913 TO OCT. 1914 - - ---------+---------+----------+----------+--------------- - |No of |No. of |Max. for |Total rainfall - |fine days|rainy days|single day|in inches - ---------+---------+----------+----------+--------------- - November | 9 | 21 | 1.150 | 4.264[34] - December | 16 | 15 | .700 | 6.439 - January | 17 | 14 | .610 | 3.313 - February | 9 | 17 | .910 | 2.975 - March | 11 | 20 | 1.102 | 4.381 - April | 17 | 13 | 0.31 | 0.92 - May | 8 | 23 | 0.35 | 1.63 - June | 27 | 3 | 0.05 | 0.07 - July | 31 | 0 | 0.00 | 0.00 - August | 31 | 0 | 0.00 | 0.00 - September| 23 | 7 | 0.05 | 0.35 - October | 21 | 10 | 0.14 | 0.56 - ---------+---------+----------+----------+--------------- - Total | | | | 24.902 - ---------+---------+----------+----------+--------------- - - -WIND - -An analysis of the wind at Santa Lucia shows an excess of north and -south winds over those of all other directions. The wind-rose for the -entire period of observation (Fig. 104) clearly expresses this fact. -When this element is removed we observe a strongly seasonal distribution -of the wind. The winter is the time of north and south winds. In summer -the winds are chiefly from the northeast or the southwest. Among single -months, August and February show this fact clearly as well as the less -decisive character of the summer (February) wind. - -The mean wind velocity for the month of February was 540 meters per -minute for the morning and 470 meters per minute for the afternoon. The -higher morning rate, an unusual feature of the weather of high -stations, or indeed of wind-phenomena in general, is due, however, to -exceptional changes in wind strength on two days of the month, the 16th -and 25th, when the velocity decreased from a little less than a thousand -meters per minute in the morning to 4 and 152 meters respectively in the -afternoon. More typical is the March record for 1914 at Santa Lucia, -when the wind was _always_ stronger in the afternoon than in the -morning, their ratios being 550 to 510. - -[Illustration: Fig. 104--Monthly wind roses for Santa Lucia, June, 1913, -to July, 1914, and composite rose for the whole period of observation.] - - -CLOUD - -The greater strength of the afternoon wind would lead us to suppose that -the cloudiness, which in the trade-wind belt, is to so great an extent -dependent on the wind, is greatest in the afternoon. The diagrams bring -out this fact. Barely is the sky quite clear after the noon hour. Still -more striking is the contrast between the morning and afternoon if we -combine the two densest shadings of the figures. Light, high-lying -cirrus clouds are most characteristic of early morning hours. They -produce some very striking sky effects just before sunrise as they catch -the sun's rays aloft. An hour or two after sunrise they disappear and -small cumulus clouds begin to form. These grow rapidly as the winds -begin and by afternoon become bulky and numerous. In the wet season they -grow into the nimbus and stratus types that precede a sudden downpour of -water or a furious hailstorm. This is best seen from the base of a -mountain range looking towards the crest, where the cloud-and -rain-making processes of this type are most active. - - CLOUD ANALYSIS, SANTA LUCIA - - --------------+---------+---------+---------+---------+---------++---------+ - | Nov. | Dec. | Jan. | Feb. | March || Total | - Type of cloud |a.m. p.m.|a.m. p.m.|a.m. p.m.|a.m. p.m.|a.m. p.m.||a.m. p.m.| - --------------+---------+---------+---------+---------+---------++---------+ - Cirrus | 6 2 | 15 2 | 9 2 | 5 3 | 6 3 || 41 12 | - Cirro-stratus | -- -- | -- -- | -- -- | -- -- | -- -- || -- -- | - Cirro-cumulus | 4 4 | 7 11 | 3 5 | 6 8 | 17 10 || 37 38 | - Cumulus | 3 4 | 4 7 | 10 9 | 15 13 | 5 13 || 37 46 | - Strato-cumulus| 2 6 | 3 10 | 7 14 | 2 3 | -- 3 || 14 36 | - Stratus | -- -- | -- 1 | -- -- | -- 1 | 1 2 || 2 4 | - Nimbus | -- -- | -- -- | -- -- | -- -- | -- -- || -- -- | - Clear | -- -- | 2 -- | 2 1 | -- -- | 2 -- || 6 1 | - --------------+---------+---------+---------+---------+---------++---------+ - - -UNUSUAL WEATHER PHENOMENA, SANTA LUCIA, 1913-14 - -[Illustration: Fig. 105--Monthly cloudiness of Santa Lucia from January -to July, 1914. Mean cloudiness for the whole period is also shown.] - -The following abstracts are selected because they give some important -features of the weather not included in the preceding tables and graphs. -Of special interest are the strong contrasts between the comparatively -high temperatures of midday and the sudden "tempests" accompanied by -rain or hail that follow the strong convectional movements dependent -upon rapid and unequal heating. The furious winds drive the particles of -hail like shot. It is sometimes impossible to face them and the pack -train must be halted until the storm has passed. Frequently they leave -the ground white with hailstones. We encountered one after another of -these "tempestades" on the divide between Lambrama and Antabamba in -1911. They are among the most impetuous little storms I have ever -experienced. The longest of them raged on the divide from two-o'clock -until dark, though in the valleys the sun was shining. Fortunately, in -this latitude they do not turn into heavy snowstorms as in the -Cordillera of northwestern Argentina, where the passes are now and then -blocked for weeks at a time and loss of human life is no infrequent -occurrence.[35] They do, however, drive the shepherds down from the -highest slopes to the mid-valley pastures and make travel uncomfortable -if not unsafe. - -ABSTRACT FROM DAILY WEATHER OBSERVATIONS, SANTA LUCIA, 1913-14 - - NOVEMBER - - "Tempest" recorded 11 times, distant thunder and lightning 9 times. - Unusual weather records: "clear sky, scorching sun, good weather" - (Nov. 29); "morning sky without a single cloud, weather agreeable" - (Nov. 30). - - DECEMBER - - Clear morning sky 6 times. Starry night or part of night 7 times. - Beginning of rain and strong wind frequently observed at 5-6 P.M. - "Tempest" mentioned 19 times--5 times at midnight, 8 times at 5-6 - P.M. - - JANUARY - - Clear morning sky 5 times. Starry night 3 times. Rain, actual or - threatening, characteristic of afternoons. "Tempest," generally - about 5-6 P.M., 7 times. Sun described 4 times as scorching and, - when without wind, heat as stifling. Weather once "agreeable." - - FEBRUARY - - Constant cloud changes, frequent afternoon or evening rains. - "Tempest," generally 4 P.M. and later, 16 times. - - MARCH - - Twice clear morning skies, once starry night. Scorching sun and - stifling heat on one occasion. "Tempest," generally in late - afternoon and accompanied by hail, 19 times. Observed 3 or 4 times - a strong, "land breeze" (terral) of short duration (15-20 mins.) - and at midnight. - - -MOROCOCHA - -Morococha, in the Department of Ancachs, Peru, lies in 76° 11' west -longitude and 11° 45' south latitude and immediately east of the crest -line of the Maritime Cordillera. It is 14,300 feet above sea level, and -is surrounded by mountains that extend from 1,000 to 3,000 feet higher. -The weather records are of special interest in comparison with those of -Santa Lucia. Topographically the situations of the two stations are -closely similar hence we may look for climatic differences dependent on -the latitudinal difference. This is shown in the heavier rainfall of -Morococha, 4° nearer the equatorial climatic zone. (For location see -Fig. 66.) - -The meteorological data for 1908-09 were obtained from records kept by -the Morococha Mining Company for use in a projected hydro-electric -installation. Other data covering the years 1906-11 have appeared in the -bulletins of the _Sociedad Geográfica de Lima_. These are not complete -but they have supplied rainfall data for the years 1910-11;[36] those -for 1906 and 1907 have been obtained from the _Boletín de Minas_.[37] - - -TEMPERATURE - -The most striking facts expressed by the various temperature curves are -the shortness of the true winter season--its restriction to June and -July--and its abrupt beginning and end. This is well known to anyone who -has lived from April to October or November at high elevations in the -Central Andes. Winter comes on suddenly and with surprising regularity -from year to year during the last few days of May and early June. In the -last week of July or the first week of August the temperatures make an -equally sudden rise. During 1908 and 1909 the mean temperature reached -the freezing point but once each year--July 24 and July 12 -respectively. The absolute minimum for the two years was -22° C. July of -1908 and June of 1909 are also the months of smallest diurnal -variability, showing that the winter temperatures are maintained with -great regularity. Like all tropical high-level stations, Morococha -exhibits winter maxima that are very high as compared with the winter -maxima of the temperate zone. In both June and July of 1908 and 1909 the -maximum was maintained for about a week above 55° F. (12.8° C.), and in -1909 above 60° F. (15.6° C.), the mean maximum for the year being only -4.7° F. higher. For equal periods, however, the maxima fell to levels -about 10° F. below those for the period from December to May, 1908. - -It is noteworthy that the lowest maximum for 1909 was in October, 44° F. -(6.7° C.); and that other low maxima but little above those of June and -July occur in almost all the other months of the year. While 1909 was in -this respect an exceptional year, it nevertheless illustrates a fact -that may occur in any month of any year. Its occurrence is generally -associated with cloudiness. One of the best examples of this is found in -the January maximum curve for 1909, where in a few days the maxima fell -12° F. Cloud records are absent, hence a direct comparison cannot be -made, but a comparison of the maximum temperature curve with the graphic -representation of mean monthly rainfall, will emphasize this relation of -temperature and cloudiness. February was the wettest month of both 1908 -and 1909. In sympathy with this is the large and sharp drop from the -January level of the maxima--the highest for the year--to the February -level. The mean temperatures are affected to a less degree because the -cloudiness retards night radiation of heat, thus elevating the maxima. -Thus in 1908 the lowest minimum for both January and February was 28.4° -F. (-2° C.). For 1909 the minima for January and February were 27.5° F. -(-2.5° C.) and 29.3° F. (-1.5° C.) respectively. - -[Illustration: FIG. 106 A--DIURNAL TEMPERATURE, MOROCOCHA, 1908 - -B--DIURNAL TEMPERATURE, MOROCOCHA, 1909 - -D--DIURNAL RANGE OF TEMPERATURE, MOROCOCHA, 1908 - -E--DIURNAL RANGE OF TEMPERATURE, MOROCOCHA, 1909 - -G--DIURNAL VARIABILITY OF TEMPERATURE, MOROCOCHA, 1908 - -H--DIURNAL VARIABILITY OF TEMPERATURE, MOROCOCHA, 1909 - -C--MEAN MONTHLY TEMPERATURE, MOROCOCHA - -F--MONTHLY MEANS OF DIURNAL RANGE OF TEMPERATURE, MOROCOCHA] - -The extent to which high minima may hold up the mean temperature is -shown by the fact that the mean monthly temperature for January, 1908, -was lower than for February. Single instances illustrate this relation -equally well. For example, on March 5th, 1908, there occurred the -heaviest rainfall of that year. The maximum and minimum curves almost -touch. The middle of April and late September, 1909, are other -illustrations. The relationship is so striking that I have put the two -curves side by side and have had them drawn to the same scale. - - FREQUENCY OF THE DIURNAL VARIABILITY, MOROCOCHA, 1908 AND 1909 - - 1908 - ----------------------------------------------------------------- - Degrees | | | | | | | | | | | | |Total No. - F. | J.| F.| M.| A.| M.| J.| J.| A.| S.| O.| N.| D.| of days - --------+---+---+---+---+---+---+---+---+---+---+---+---+--------- - 0 | --| 3 | 2 | 3 | --| --| 2 | 1 | 3 | 1 | 1 | 3 | 19 - 0-1 | 6 | 5 | 6 |10 | 9 |10 |13 |10 | 8 | 6 | 6 | 5 | 94 - 1-2 | 4 | 1 | 3 | 7 | 5 | 3 | 7 | 7 | 8 | 6 | 6 | 4 | 61 - 2-3 | 6 | 1 | 3 | 4 | 9 | 2 | 2 | 4 | 4 | 7 | 7 | 4 | 53 - 3-4 | 5 | 3 | 2 | 3 | 3 | 4 | 2 | 9 | 4 | 5 | 3 | 5 | 48 - 4-5 | 2 | 3 | 1 | 1 | 2 | 5 | 5 | --| 1 | 1 | 6 | 3 | 30 - Over 5 | 3 | 4 | 3 | 2 | 3 | 6 | --| --| 2 | 5 | 1 | 5 | 34 - --------+---+---+---+---+---+---+---+---+---+---+---+---+--------- - Days per|26 |20 |20 |30 |31 |30 |31 |31 |30 |31 |30 |20 | 339 - month | | | | | | | | | | | | | - ------------------------------------------------------------------ - 1909 - --------------------------------------------------------------------- - | | | | | | | | | | | | | |Mean - Degrees | | | | | | | | | | | | |Total |for - F. | J.| F.| M.| A.| M.| J.| J.| A.| S.| O.| N.| D.|No. of|1908 - | | | | | | | | | | | | | days |-1909 - --------+---+---+---+---+---+---+---+---+---+---+---+---+------+----- - 0 | 6 | 1 | 4 | 2 | 1 | 2 | 4 | 4 | 3 | 6 | 2 | 1 | 36 | 27.5 - 0-1 | 9 | 8 | 5 | 6 | 6 | 7 | 8 |13 | 9 | 4 |11 |10 | 96 | 95 - 1-2 | 4 | 6 | 8 | 3 |11 |14 | 3 | 3 | 5 | 3 | 9 | 6 | 75 | 68 - 2-3 | 3 | 7 | 4 | 8 | 4 | 3 | 6 | 6 | 4 | 6 | 1 | 3 | 55 | 54 - 3-4 | 4 | 5 | 3 | 6 | 4 | 4 | 4 | 3 | 6 | 3 | 2 | 5 | 49 | 48.5 - 4-5 | 1 | 1 | 5 | 1 | 2 | --| 2 | 1 | 1 | 2 | --| 2 | 18 | 24 - Over 5 | 4 | --| 2 | 4 | 3 | --| 4 | 1 | 2 | 7 | 5 | 3 | 35 | 34.5 - --------+---+---+---+---+---+---+---+---+---+---+---+---+------+----- - Days per|31 |28 |31 |30 |31 |30 |31 |31 |30 |31 |30 |30 | 364 |351.5 - month | | | | | | | | | | | | | | - --------------------------------------------------------------------- - - -RAINFALL - -The annual rainfall of Morococha is as follows: - - 1906 28 inches ( 712 mm.) - 1907 40 " (1,011 mm.)[38] - 1908 57 " (1,450 mm.) - 1909 45 " (1,156 mm.) - 1910 47 " (1,195 mm.) - 1911 25 " ( 622 mm.) - -[Illustration: FIG. 107A.] - -[Illustration: FIG. 107B.] - -[Illustration: FIG. 107C.] - -[Illustration: Fig. 107--Rainfall of Morococha. Fig. 107A shows daily -rainfall during the rainy (summer) season, 1908-1909. Fig. 107B shows -monthly rainfall from July, 1905, to December, 1911, and Fig. 107C the -annual and mean rainfall for the same period.] - -The mean for the above six years amounts to 40 inches (1,024 mm.). This -is a value considerably higher than that for Caylloma or Santa Lucia. -The greater rainfall of Morococha is probably due in part to its more -northerly situation. An abnormal feature of the rainfall of 1908, the -rainiest year, is the large amount that fell in June. Ordinarily June -and July, the coldest months, are nearly or quite rainless. The normal -concurrence of highest temperatures and greatest precipitation is of -course highly favorable to the plant life of these great altitudes. Full -advantage can be taken of the low summer temperatures if the growing -temperatures are concentrated and are accompanied by abundant rains. -Since low temperatures mean physiologic dryness, whether or not rains -are abundant, the dryness of the winter months has little effect in -restricting the range of Alpine species. - -The seasonal distribution of rain helps the plateau people as well as -the plateau plants. The transportation methods are primitive and the -trails mere tracks that follow the natural lines of topography and -drainage. Coca is widely distributed, likewise corn and barley which -grow at higher elevations, and wool must be carried down to the markets -from high-level pastures. In the season of rains the trails are -excessively wet and slippery, the streams are often in flood and the -rains frequent and prolonged. On the other hand the insignificant -showers of the dry or non-growing season permit the various products to -be exchanged over dry trails. - -The activities of the plateau people have had a seasonal expression from -early times. Inca chronology counted the beginning of the year from the -middle of May, that is when the dry season was well started and it was -inaugurated with the festivals of the Sun. With the exception of June -when the people were entirely busied in the irrigation of their fields, -each month had its appropriate feasts until January, during which month -and February and March no feasts were held. April, the harvest month, -marked the recommencement of ceremonial observances and a revival of -social life.[39] - -In Spanish times the ritualistic festivals, incorporated with fairs, -followed the seasonal movement. Today progress in transportation has -caused the decadence of many of the fairs but others still survive. Thus -two of the most famous fairs of the last century, those of Vilque -(province of Puno) and Yunguyo (province of Chucuito), were held at the -end of May and the middle of August respectively. Copacavana, the famous -shrine on the shores of Titicaca, still has a well-attended August fair -and Huari, in the heart of the Bolivian plateau, has an Easter fair -celebrated throughout the Andes. - - -COCHABAMBA - -Cochabamba, Bolivia, lies 8,000 feet above sea level in a broad basin in -the Eastern Andes. The Cerro de Tunari, on the northwest, has a snow and -ice cover for part of the year. The tropical forests lie only a single -long day's journey to the northeast. Yet the basin is dry on account of -an eastern front range that keeps out the rain-bearing trade winds. The -Rio Grande has here cut a deep valley by a roundabout course from the -mountains to the plains so that access to the region is over bordering -elevations. The basin is chiefly of structural origin. - -The weather records from Cochabamba are very important. I could obtain -none but temperature data and they are complete for 1906 only. Data for -1882-85 were secured by von Boeck[40] and they have been quoted by -Sievers and Hann. The mean annual temperature for 1906 was 61.9° F. -(16.6° C.), a figure in close agreement with von Boeck's mean of 60.8° -F. (16° C.). The monthly means indicate a level of temperature favorable -to agriculture. The basin is in fact the most fertile and highly -cultivated area of its kind in Bolivia. Bananas, as well as many other -tropical and subtropical plants, grow in the central plaza. The nights -of midwinter are uncomfortably cool; and the days of midsummer are -uncomfortably hot but otherwise the temperatures are delightful. The -absolute extremes for 1906 were 81.5° F. (27.5° C.) on December 11, and -39.9° F. (4.4° C.) on July 15 and 16. The (uncorrected) readings of von -Boeck give a greater range. High minima rather than high maxima -characterize the summer. The curve for 1906 shows the maxima for June -and July cut off strikingly by an abrupt drop of the temperature and -indicates a rather close restriction of the depth of the season to these -two months, which are also those of greatest diurnal range. - -[Illustration: FIG. 108 A--DIURNAL TEMPERATURE, COCHABAMBA, 1906 - -B--DIURNAL TEMPERATURE, COCHABARMBA, 1907 - -E--DIURNAL RANGE OF TEMPERATURE, COCHABARMBA, 1907 - -D--DIURNAL RANGE OF TEMPERATURE, COCHABARMBA, 1906 - -G--DIURNAL VARIABILITY, COCHABARMBA, 1906 - -H--DIURNAL VARIABILITY, COCHABAMBA, 1907 - -C--MEAN MONTHLY TEMPERATURES, COCHABAMBA - -F--MONTHLY MEANS OF DIURNAL RANGE, COCHABAMBA] - -The rainfall of about 18 inches is concentrated in the summer season, 85 -per cent falling between November and March. During this time the town -is somewhat isolated by swollen streams and washed out trails: hence -here, as on the plateau, there is a distinct seasonal distribution of -the work of planting, harvesting, moving goods, and even mining, and of -the general commerce of the towns. There is an approach to our winter -season in this respect and in respect of a respite from the almost -continuously high temperatures of summer. The daytime temperatures of -summer are however mitigated by the drainage of cool air from the -surrounding highlands. This, indeed, prolongs the period required for -the maturing of plants, but there are no harmful results because -freezing temperatures are not reached, even in winter. - - MONTHLY TEMPERATURES, COCHABAMBA, 1906 - - -------------+-------------+-------------+-------------+-------------- - Month | Mean Min. | Mean Max. | Mean Range | Daily Mean - -------------+-------------+-------------+-------------+-------------- - January | 55.7 | 72.25 | 16.65 | 63.3 - February | 61.2 | 71.3 | 10.1 | 65.5 - March | 59.8 | 72.6 | 12.8 | 65.5 - April | 55.06 | 70.8 | 15.74 | 62.2 - May | 50.9 | 68.7 | 17.8 | 59.1 - June | 47.1 | 65.6 | 18.5 | 55.6 - July | 44.8 | 64.9 | 20.1 | 54.1 - August | 49.9 | 68.0 | 18.1 | 58.2 - September | 55.6 | 73.2 | 17.6 | 63.7 - October | 56.1 | 73.4 | 17.3 | 64.0 - November | 58.1 | 75.7 | 17.6 | 66.2 - December | 58.6 | 73.9 | 15.3 | 65.8 - -------------+-------------+-------------+-------------+-------------- - -[Illustration: FIGS. 109-113--Temperature curves for locations in the -montaña, July and August, 1911. The curves are based on hourly readings -with interpolated readings for such critical occurrences as the -appearance of cloud or rain. Dry bulb readings are shown by solid lines, -wet bulb by dotted lines, and breaks in the continuity of the -observations by heavy broken lines. Fig. 109 is for Pongo de Mainique, -August 20 and 21; Fig. 110 for Yavero; Fig. 111 for Santo Anato, August -11 and 12; Fig. 112 for Sahuayaco, August 20, and Fig. 113 for Santa -Ana, July 30 to August 1.] - -[Illustration: FIG. 114--Typical afternoon cloud composition at Santa -Ana during the dry season.] - -[Illustration: FIG. 115--Temperature curve for Abancay drawn from data -obtained by hourly readings on September 27, 1911. Dry bulb readings are -shown by a heavy solid line, wet bulb readings by a dotted line. The -heavy broken line shows the normal curve when the sky is unobscured by -cloud. The reduction in temperature with cloud is very marked.] - - FREQUENCY OF DIURNAL VARIABILITY AT COCHABAMBA, 1906 - - -------+----+----+----+----+----+----+----+----+----+----+----+----++------ - | | | | | | | | | | | | ||Total - Degrees| | | | | | | | | | | | ||No. of - F. | J. | F. | M. | A. | M. | J. | J. | A. | S. | O. | N. | D. || days - -------+----+----+----+----+----+----+----+----+----+----+----+----++------ - 0 | 1 | 3 | 10 | 12 | 6 | 10 | 9 | 6 | 9 | 6 | 3 | 4 || 79 - 0-1 | 5 | -- | 3 | 5 | 3 | 3 | -- | 4 | -- | 3 | 1 | 1 || 28 - 1-2 | 10 | 10 | 13 | 11 | 15 | 7 | 14 | 11 | 15 | 10 | 14 | 13 || 143 - 2-3 | 7 | 11 | 3 | 1 | 5 | 8 | 7 | 4 | 3 | 6 | 7 | 6 || 68 - 3-4 | 6 | 2 | 2 | 1 | 2 | 2 | 1 | 6 | 3 | 4 | 3 | 5 || 37 - 4-5 | -- | -- | -- | -- | -- | -- | -- | -- | -- | 1 | 1 | 1 || 3 - Over 5 | 2 | 2 | -- | -- | -- | -- | -- | -- | -- | 1 | 1 | 1 || 7 - -------+----+----+----+----+----+----+----+----+----+----+----+----++------ - -A series of curves shows the daily march of temperature at various -locations along the seventy-third meridian. Figs. 109 to 113 are for the -Urubamba Valley. Respectively they relate to Pongo de Mainique, 1,200 -feet elevation (365 m.), the gateway to the eastern plains; Yavero, -1,600 feet (488 m.), where the tributary of this name enters the main -stream; Santo Anato, 1,900 feet (580 m.); Sahuayaco, 2,400 feet (731 -m.), and Santa Ana, 3,400 feet (1,036 m.), one of the outposts of -civilization beyond the Eastern Cordillera. The meteorological -conditions shown are all on the same order. They are typical of dry -season weather on the dry floor of a montaña valley. The smooth curves -of clear days are marked by high mid-day temperatures and great diurnal -range. Santo Anato is a particularly good illustration: the range for -the 24 hours is 38° F. (21.1° C.). This site, too, is remarkable as one -of the most unhealthful of the entire valley. The walls of the valley -here make a sharp turn and free ventilation of the valley is obstructed. -During the wet season tertian fever prevails to a degree little known -east of the Cordillera, though notorious enough in the deep valleys of -the plateau. The curves show relative humidity falling to a very low -minimum on clear days. At Santo Anato and Santa Ana, for example, it -drops below 30 per cent during the heat of the day. Afternoon -cloudiness, however, is a common feature even of the dry season. A -typical afternoon cloud formation is shown in Fig. 114. The effect on -temperature is most marked. It is well shown in the curve for August 20 -and 22 at Yavero. Cloudiness and precipitation increase during the -summer months. At Santa Ana the rainfall for the year 1894-95 amounted -to 50 inches, of which 60 per cent fell between December and March. For -a discussion of topographic features that have some highly interesting -climatic effects in the eastern valleys of Peru see Chapter VI. - -[Illustration: FIGS. 116-118--Temperature curves for locations in the -Maritime Cordillera and its western valleys, October, 1911. For -construction of curves see Figs. 109-113. Fig. 116 is for Camp 13 on the -northern slope of the Maritime Cordillera (which here runs from east to -west), October 13-15; Fig. 117 for Cotahuasi, October 26; Fig. 118 for -Salamanca, October 31.] - -[Illustration: FIG. 119. - -FIG. 120. - -FIGS. 119-120--Temperature curves for the Coast Desert, November, 1911. -Fig. 119 is for Aplao, November 4 and 5; and Fig. 120 for Camaná, -November 9 and 10. For construction of curves see Figs. 109 to 113.] - -Abancay, 8,000 feet (2,440 m.), in one of the inter-Andean basins, is -situated in the zone of marked seasonal precipitation. The single day's -record shows the characteristic effect of cloud reducing the maximum -temperature of the day and maintaining the relative humidity. - -Camp 13, 15,400 feet (4,720 m.), lies near the crest of the Maritime -Cordillera a little south of Antabamba. Afternoon storms are one of its -most significant features. Cotahuasi, 9,100 feet (2,775 m.) is near the -head of a west-coast valley. Its low humidity is worthy of note. That -for Salamanca, 12,700 feet (3,870 m.), is similar but not so marked. - -Aplao, 3,100 feet (945 m.), and Camaná at the seacoast are stations in -the west-coast desert. The interior location of the former gives it a -greater range of temperature than Camaná, yet even here the range is -small in comparison with the diurnal extremes of the montaña, and the -tempering effect of the sea-breeze is clearly apparent. Camaná shows a -diurnal temperature range of under 10° F. and also the high relative -humidity, over 70 per cent, characteristic of the coast. - - - - -PART II - -PHYSIOGRAPHY OF THE PERUVIAN ANDES - - - - -CHAPTER XI - -THE PERUVIAN LANDSCAPE - - -From the west coast the great Andean Cordillera appears to have little -of the regularity suggested by our relief maps. Steep and high cliffs in -many places form the border of the land and obstruct the view; beyond -them appear distant summits rising into the zone of clouds. Where the -cliffs are absent or low, one may look across a sun-baked, yellow -landscape, generally broken by irregular foothills that in turn merge -into the massive outer spurs and ranges of the mountain zone. The plain -is interrupted by widely separated valleys whose green lowland meadows -form a brilliant contrast to the monotonous browns and yellows of the -shimmering desert. In rare situations the valley trenches enable one to -look far into the Cordillera and to catch memorable glimpses of lofty -peaks capped with snow. - -If the traveler come to the west-coast landscape from the well-molded -English hills or the subdued mountains of Vermont and New Hampshire with -their artistic blending of moderate profiles, he will at first see -nothing but disorder. The scenery will be impressive and, in places, -extraordinary, but it is apparently composed of elements of the greatest -diversity. All the conceivable variations of form and color are -expressed, with a predominance of bold rugged aspects that give a -majestic appearance to the mountain-bordered shore. One looks in vain -for some sign of a quiet view, for some uniformity of features, for some -landscape that will remind him of the familiar hills of home. The Andes -are aggressive mountains that front the sea in formidable spurs or -desert ranges. Could we see in one view their entire elevation from -depths of over 20,000 feet beneath sea level to snowy summits, a total -altitude of 40,000 feet (12,200 m.), their excessive boldness would be -more apparent. No other mountains in the world are at once so -continuously lofty and so near a coast which drops off to abyssal -depths. - -The view from the shore is, however, but one of many which the Andes -exhibit. Seen from the base the towering ranges display a stern aspect, -but, like all mountains, their highest slopes and spurs must be crossed -and re-crossed before the student is aware of other aspects of a quite -different nature. The Andes must be observed from at least three -situations: from the floors of the deep intermontane valleys, from the -intermediate slopes and summits, and from the uppermost levels as along -the range crests and the highest passes. Strangely enough it is in the -summit views that one sees the softest forms. At elevations of 14,000 to -16,000 feet (4,270 to 4,880 m.), where one would expect rugged spurs, -serrate chains, and sharp needles and horns, one comes frequently upon -slopes as well graded as those of a city park--grass-covered, -waste-cloaked, and with gentle declivity (Figs. 121-124). - -The graded, waste-cloaked slopes of the higher levels are interpreted as -the result of prolonged denudation in an erosion cycle which persisted -through the greater part of the Tertiary period, and which was closed by -uplifts aggregating at least several thousands of feet. Above the level -of the mature slopes rise the ragged profiles and steep, naked -declivities of the snow-capped mountains which bear residual relations -to the softer forms at their bases. They are formed upon rock masses of -greater original elevation and of higher resistance to denudation. -Though they are dominating topographic features, they are much less -extensive and significant than the tame landscape which they surmount. - -[Illustration: FIG. 121--Looking north from the hill near Anta in the -Anta basin north of Cuzco. Typical composition of slopes and intermont -basins in the Central Andes. Alluvial fill in the foreground; mature -slopes in the background; in the extreme background the snow-capped -crests of the Cordillera Vilcapampa.] - -[Illustration: FIG. 122--Showing topographic conditions before the -formation of the deep canyons in the Maritime Cordillera. The view, -looking across a tributary canyon of the Antabamba river, shows in the -background the main canyon above Huadquirca. Compare with Fig. 60.] - -Below the level of the mature slopes are topographic features of equal -prominence: gorges and canyons up to 7,000 feet deep. The deeply -intrenched streams are broken by waterfalls and almost continuous -rapids, the valley walls are so abrupt that one may, in places, roll -stones down a 4,000 foot incline to the river bed, and the tortuous -trail now follows a stream in the depths of a profound abyss, now scales -the walls of a labyrinthine canyon. - -[Illustration: FIG. 123--Mature slopes between Ollantaytambo and -Urubamba.] - -[Illustration: FIG. 124--Dissected mature slopes north of Anta in the -Anta basin north of Cuzco.] - -[Illustration: FIG. 125--Mature upper and young lower slopes at the -outlet of the Cuzco basin.] - -The most striking elements of scenery are not commonly the most -important in physiography. The oldest and most significant surface may -be at the top of the country, where it is not seen by the traveler or -where it cannot impress him, except in contrast to features of greater -height or color. The layman frequently seizes on a piece of bad-land -erosion or an outcrop of bright-colored sandstone or a cliff of -variegated clays or a snow-covered mountain as of most interest. All we -can see of a beautiful snow-clad peak is mere entertainment compared -with what subdued waste-cloaked hill-slopes may show. We do not wish to -imply that everywhere the tops of the Andes are meadows, that there are -no great scenic features in the Peruvian mountains, or that they are not -worth while. But we do wish to say that the bold features are far less -important in the interpretation of the landscape. - -Amid all the variable forms of the Peruvian Cordillera certain strongly -developed types recur persistently. That their importance and relation -may be appreciated we shall at once name them categorically and -represent them in the form of a block diagram (Fig. 126). The principal -topographic types are as follows: - - 1. An extensive system of high-level, well-graded, mature slopes, - below which are: - - 2. Deep canyons with steep, and in places, cliffed sides and narrow - floors, and above which are: - - 3. Lofty residual mountains composed of resistant, highly deformed - rock, now sculptured into a maze of serrate ridges and sharp - commanding peaks. - - 4. Among the forms of high importance, yet causally unrelated to - the other closely associated types, are the volcanic cones and - plateaus of the western Cordillera. - - 5. At the valley heads are a full complement of glacial features, - such as cirques, hanging valleys, reversed slopes, terminal - moraines, and valley trains. - - 6. Finally there is in all the valley bottoms a deep alluvial fill - formed during the glacial period and now in process of dissection. - -Though there are in many places special features either remotely related -or quite unrelated to the principal enumerated types, they belong to the -class of minor forms to which relatively small attention will be paid, -since they are in general of small extent and of purely local interest. - -[Illustration: FIG. 126--Block diagram of the typical physiographic -features of the Peruvian Andes.] - -The block diagram represents all of these features, though of necessity -somewhat more closely associated than they occur in nature. Reference to -the photographs, Figs. 121-124, will make it clear that the diagram is -somewhat ideal: on the other hand the photographs together include all -the features which the diagram displays. In descending from any of the -higher passes to the valley floor one passes in succession down a steep, -well-like cirque at a glaciated valley head, across a rocky terminal -moraine, then down a stair-like trail cut into the steep scarps which -everywhere mark the descent to the main valley floors, over one after -another of the confluent alluvial fans that together constitute a large -part of the valley fill, and finally down the steep sides of the inner -valley to the boulder-strewn bed of the ungraded river. - -We shall now turn to each group of features for description and -explanation, selecting for first consideration the forms of widest -development and greatest significance--the high-level mature slopes -lying between the lofty mountains which rise above them and the deep, -steep-walled valleys sunk far below them. These are the great pasture -lands of the Cordillera; their higher portions constitute the typical -_puna_ of the Indian shepherds. In many sections it is possible to -pasture the vagrant flocks almost anywhere upon the graded slopes, -confident that the _ichu_, a tufted forage grass, will not fail and that -scattered brooks and springs will supply the necessary water. At -nightfall the flocks are driven down between the sheltering walls of a -canyon or in the lee of a cliff near the base of a mountain, or, failing -to reach either of these camps, the shepherd confines his charge within -the stone walls of an isolated corral. - -In those places where the graded soil-covered slopes lie within the zone -of agriculture--below 14,000 feet--they are cultivated, and if the soil -be deep and fertile they are very intensively cultivated. Between Anta -and Urubamba, a day's march north of Cuzco, the hill slopes are covered -with wheat and barley fields which extend right up to the summits (Fig. -134). In contrast are the uncultivated soil-less slopes of the mountains -and the bare valley walls of the deeply intrenched streams. The -distribution of the fields thus brings out strongly the principal -topographic relations. Where the softer slopes are at too high a level, -the climatic conditions are extreme and man is confined to the valley -floors and lower slopes where a laborious system of terracing is the -first requirement of agriculture. - -The appearance of the country after the mature slopes had been formed is -brought out in Fig. 122. The camera is placed on the floor of a still -undissected, mature valley which shows in the foreground of the -photograph. In the middle distance is a valley whose great depth and -steepness are purposely hidden; beyond the valley are the smoothly -graded, catenary curves, and interlocking spurs of the mature upland. In -imagination one sees the valleys filled and the valley slopes confluent -on the former (now imaginary) valley floor which extends without -important change of expression to the border of the Cordillera. No -extensive cliffs occur on the restored surface, and none now occur on -large tracts of the still undissected upland. Since the mature slopes -represent a long period of weathering and erosion, their surfaces were -covered with a deep layer of soil. Where glaciation at the higher levels -and vigorous erosion along the canyons have taken place, the former soil -cover has been removed; elsewhere it is an important feature. Its -presence lends a marked softness and beauty to these lofty though -subdued landscapes. - -The graded mountain slopes were not all developed (1) at the same -elevation, nor (2) upon rock of the same resistance to denudation, nor -(3) at the same distance from the major streams, nor (4) upon rock of -the same structure. It follows that they will not all display precisely -the same form. Upon the softer rocks at the lowest levels near the -largest streams the surface was worn down to extremely moderate slopes -with a local relief of not more than several hundred feet. Conversely, -there are quite unreduced portions whose irregularities have mountainous -proportions, and between these extremes are almost all possible -variations. Though the term _mature_ in a broad way expresses the stage -of development which the land had reached, _post mature_ should be -applied to those portions which suffered the maximum reduction and now -exhibit the softest profiles. At no place along the 73rd meridian was -denudation carried to the point of even local peneplanation. All of the -major and some of the minor divides bear residual elevations and even -approximately plane surfaces do not exist. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM, DIRECTOR - -COROPUNA QUADRANGLE - -(_Cotahuasi_)] - -Among the most important features of the mature slopes are (1) their -great areal extent--they are exhibited throughout the whole Central -Andes, (2) their persistent development upon rocks of whatever structure -or degree of hardness, and (3) their present great elevation in spite of -moderate grades indicative of their development at a much lower -altitude. Mature slopes of equivalent form are developed in widely -separated localities in the Central Andes: in every valley about -Cochabamba, Bolivia, at 10,000 feet (3,050 m.); at Crucero Alto in -southern Peru at 14,600 feet (4,450 m.); several hundred miles farther -north at Anta near Cuzco, 11,000 feet to 12,000 feet (3,600 to 3,940 -m.), and Fig. 129 shows typical conditions in the Vilcabamba Valley -along the route of the Yale Peruvian Expedition of 1911. The -characteristic slopes so clearly represented in these four photographs -are the most persistent topographic elements in the physiography of the -Central Andes. - -[Illustration: FIG. 127--Topographic profiles across typical valleys of -southern Peru. They are drawn to scale and the equality of gradient of -the gentler upper slopes is so close that almost any curve would serve -as a composite of the whole. These curves form the basis of the diagram, -Fig. 128, whereby the amount of elevation of the Andes in late geologic -time may be determined. The approximate locations of the profiles are as -follows: 1, Antabamba; 2, Chuquibambilla; 3, upland south of Antabamba; -4, Apurimac Canyon above Pasaje; 5, Abancay; 6, Arma (Cordillera -Vilcapampa); 7, divide above Huancarama; 8, Huascatay; 9, Huasentay, -farther downstream; 10, Rio Pampas. The upper valley in 8 is still -undissected; 7 is practically the same; 8a is at the level which 8 must -reach before its side slopes are as gentle as at the end of the -preceding interrupted cycle.] - -The rock masses upon which the mature slopes were formed range from soft -to hard, from stratified shales, slates, sandstones, conglomerates, and -limestones to volcanics and intrusive granites. While these variations -impose corresponding differences of form, the graded quality of the -slopes is rarely absent. In some places the highly inclined strata are -shown thinly veiled with surface débris, yet so even as to appear -artificially graded. The rock in one place is hard granite, in another a -moderately hard series of lava flows, and again rather weak shales and -sandstones. - -Proof of the rapid and great uplift of certain now lofty mountain ranges -in late geologic time is one of the largest contributions of -physiography to geologic history. Its validity now rests upon a large -body of diversified evidence. In 1907 I crossed the Cordillera Sillilica -of Bolivia and northern Chile and came upon clear evidences of recent -and great uplift. The conclusions presented at that time were tested in -the region studied in 1911, 500 miles farther north, with the result -that it is now possible to state more precisely the dates of origin of -certain prominent topographic forms, and to reconstruct the conditions -which existed before the last great uplift in which the Central Andes -were born. The relation to this general problem of the forms under -discussion will now be considered. - -The gradients of the mature slopes, as we have already seen, are -distinctly moderate. In the Anta region, over an area several hundred -square miles in extent, they run from several degrees to 20° or 30°. -Ten-degree slopes are perhaps most common. If the now dissected slopes -be reconstructed on the basis of many clinometer readings, photographs, -and topographic maps, the result is a series of profiles as in Fig. 127. -If, further, the restored slopes be coördinated over an extensive area -the gradients of the resulting valley floors will run from 3° to 10°. -Finally, if these valley floors be extended westward to the Pacific and -eastward to the Amazon basin, they will be found about 5,000 feet above -sea level and 4,000 feet above the eastern plains. (For explanation of -method and data employed, see the accompanying figures 127-128). It is, -therefore, a justifiable conclusion that since the formation of the -slopes the Andes have been uplifted at least a mile, or, to put it in -another way, the Andes at the time of formation of the mature slopes -were at least a mile lower than they are at present. - -[Illustration: FIG. 128--Composition of slopes and profiles in the -Peruvian Andes. By superimposing the cross profiles of typical valleys -as shown in Fig. 127 a restoration is possible of the longitudinal -profiles of the earlier cycle of erosion. The difference in elevation of -the two profiles gives less than the minimum amount of uplift that must -have occurred. Case A represents a valley in which recent cutting has -not yet reached the valley head. Below the point 1 the profile has been -steepened and lowered by erosion in the current cycle. Above point 1 the -profile is still in the stage it reached in the preceding cycle. In case -B the renewed erosion of the current cycle has reached to the valley -head. Case C represents conditions similar to those in the preceding -cases save that the stream is typical of those that lie nearest the -steep flexed or faulted margins of the Cordillera and discharge to the -low levels of the desert pampa on the west or the tropical plains on the -east.] - -Further proof of recent and great uplift is afforded by the deeply -intrenched streams. After descending the long graded slopes one comes -upon the cliffed canyons with a feeling of consternation. The effect of -powerful erosion, incident upon uplift, is heightened by the ungraded -character of the river bed. Falls and rapids abound, the river profiles -suggest tumultuous descents, and much time will elapse before the river -beds have the regular and moderate gradients of the streams draining the -mature surface before uplift as shown in the profiles by the dotted -lines representing the restored valley floors of the older cycle. Since -the smooth-contoured landscape was formed great changes have taken -place. The streams have changed from completely graded to almost -completely ungraded profiles; in place of a subdued landscape we now -have upland slopes intersected by mile-deep canyons; the high-level -slopes could not have been formed under existing conditions, for they -are being dissected by the present streams. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM, DIRECTOR - -COTAHUASI QUADRANGLE - -(_La Cumbre_)] - -Since the slopes of the land in general undergo progressive changes in -the direction of flatter gradients during a given geographical cycle, it -follows that with the termination of one cycle and the beginning of -another, two sets of slopes will exist and that the gradients of the two -will be unlike. The result is a break in the descent of the slopes from -high to low levels to which the name "topographic unconformity" is now -applied. It will be a prominent feature of the landscape if the higher, -older, and flatter gradients have but little declivity, and the -gradients of the lower younger slopes are very steep. In those places -where the relief of the first cycle was still great at the time of -uplift, the erosion forms of the second cycle may not be differentiated -from those of the first, since both are marked by steep gradients. In -the Central Andes the change in gradient between the higher and lower -slopes is generally well marked. It occurs at variable heights above -the valley floors, though rarely more than 3,000 feet above them. In the -more central tracts, far from the main streams and their associated -canyons, dissection in the present erosion cycle has not yet been -initiated, the mature slopes are still intact, and a topographic -unconformity has not yet been developed. The higher slopes are faced -with rock and topped with slowly moving waste. Ascent of the spur end is -by steep zigzag trails; once the top is gained the trail runs along the -gentler slopes without special difficulties. - -It is worth noting at this point that the surface of erosion still older -than the mature slopes herewith described appears not to have been -developed along the seventy-third meridian of Peru, or if developed at -one time, fragments of it no longer remain. The last well-developed -remnant is southwest of Cuzco, Fig. 130. I have elsewhere described the -character and geographic distribution of this oldest recognizable -surface of the Central Andes.[41] Southern Peru and Bolivia and northern -Chile display its features in what seems an unmistakable manner. The -best locality yet found is in the Desaguadero Valley between Ancoaqui -and Concordia. There one may see thousands of feet of strongly inclined -sediments of varying resistance beveled by a well-developed surface of -erosion whose preserval is owing to a moderate rainfall and to location -in an interior basin.[42] - -The highest surface of a region, if formed during a prolonged period of -erosion, becomes a surface of reference in the determination of the -character and amount of later crustal deformations, having somewhat the -same functions as a key bed in stratigraphic geology. Indeed, concrete -physiographic facts may be the _only_ basis for arguments as to both -epeirogenic and orogenic movements. The following considerations may -show in condensed form the relative value of physiographic evidence: - -1. If movements in the earth's crust are predominantly _downward_, -sedimentation may be carried on continuously, and a clear geologic -record may be made. - -2. Even if crustal movements are alternately downward and upward, -satisfactory conclusions may be drawn from both (a) the nature of the -buried surfaces of erosion, and (b) the alternating character of the -sediments. - -3. If, however, the deformative processes effect steady or intermittent -uplifts, there may be no sediments, at least within the limits of the -positive crustal units, and a geologic record must be derived not from -sedimentary deposits but from topographic forms. We speak of the _lost -intervals_ represented by stratigraphic breaks or unconformities and -commonly emphasize our ignorance concerning them. The longest, and, from -the human standpoint, the most important, break in the sedimentary -record is that of the present wherever degradation is the predominant -physiographic process. Unlike the others the _lost interval_ of the -present is not lost, if we may so put it, but is in our possession, and -may be definitely described as a concrete thing. It is the physiography -of today. - -Even where long-buried surfaces of erosion are exposed to view, as in -northern Wisconsin, where the Pre-Cambrian paleo-plain projects from -beneath the Paleozoic sediments, or, as in New Jersey and southeastern -Pennsylvania, where the surface developed on the crystalline rocks -became by depression the floor of the Triassic and by more recent uplift -and erosion has been exposed to view,--even in such cases the exposures -are of small extent and give us at best but meager records. In short, -many of the breaks in the geologic record are of such long duration as -to make imperative the use of physiographic principles and methods. The -great Appalachian System of eastern North America has been a land area -practically since the end of the Paleozoic. In the Central Andes the -"lost interval," from the standpoint of the sedimentary, record, dates -from the close of the Cretaceous, except in a few local intermont basins -partially filled with Tertiary or Pleistocene deposits. Physiographic -interpretations, therefore, serve the double purpose of supplying a part -of the geologic record while at the same time forming a basis for the -scientific study of the surface distribution of living forms. - -The geologic dates of origin of the principal topographic forms of the -Central Andes may be determined with a fair degree of accuracy. Geologic -studies in Peru and Bolivia have emphasized the wide distribution of the -Cretaceous formations. They consist principally of thick limestones -above and sandstones and conglomerates below, and thus represent -extensive marine submergence of the earth's crust in the Cretaceous -where now there are very lofty mountains. The Cretaceous deposits are -everywhere strongly deformed or uplifted to a great height, and all have -been deeply eroded. They were involved, together with other and much -older sediments, in the erosion cycle which resulted in the development -of the widely extended series of mature slopes already described. From -low scattered island elevations projecting above sea level, as in the -Cretaceous period, the Andes were transformed by compression and uplift -to a rugged mountain belt subjected to deep and powerful erosion. The -products of erosion were in part swept into the adjacent seas, in part -accumulated on the floors of intermont basins, as in the great interior -basins of Titicaca and Poopó. - -Since the early Tertiary strata are themselves deformed from once simple -and approximately horizontal structures and subjected to moderate -tilting and faulting, it follows that mountain-making movements again -affected the region during later Tertiary. They did not, however, -produce extreme effects. They did stimulate erosion and bring about a -reorganization of all the slopes with respect to the new levels. - -This agrees closely with a second line of evidence which rests upon an -independent basis. The alluvial fill which lies upon all the canyon and -valley floors is of glacial origin, as shown by its interlocking -relations with morainal deposits at the valley heads. It is now in -process of dissection and since its deposition in the Pleistocene had -been eroded on the average about 200 feet. Clearly, to form a 3,000-foot -canyon in hard rock requires much more time than to deposit and again -partially to excavate an alluvial fill several hundred feet deep. -Moreover, the glacial material is coarse throughout, and was built up -rapidly and dissected rapidly. In most cases, furthermore, coarse -material at the bottom of the glacial series rests directly upon the -rock of a narrow and ungraded valley floor. From these and allied facts -it is concluded that there is no long time interval represented by the -transitions from degrading to aggrading processes and back again. The -early Pleistocene, therefore, seems quite too short a period in which to -produce the bold forms and effect the deep erosion which marks the -period between the close of the mature cycle and the beginnings of -deposition in the Pleistocene. - -The alternative conclusion is that the greater part of the canyon -cutting was effected in the late Tertiary, and that it continued into -the early Pleistocene until further erosion was halted by changed -climatic conditions and the augmented delivery of land waste to all the -streams. The final development of the well-graded high-level slopes is, -therefore, closely confined to a small portion of the Tertiary. The -closest estimate which the facts support appears to be Miocene or early -Pliocene. It is clear, however, that only the culmination of the period -can be definitely assigned. Erosion was in full progress at the close of -the Cretaceous and by middle Tertiary had effected vast changes in the -landscape. The Tertiary strata are marked by coarse basal deposit and by -thin and very fine top deposits. Though their deformed condition -indicates a period of crustal disturbance, the Tertiary beds give no -indication of wholesale transformations. They indicate chiefly tilting -and moderate and normal faulting. The previously developed effects of -erosion were, therefore, not radically modified. The surface was thus in -large measure prepared by erosion in the early Tertiary for its final -condition of maturity reached during the early Pliocene. - -It seems appropriate, in concluding this chapter, to summarize in its -main outlines the physiography of southern Peru, partly to condense the -extended discussion of the preceding paragraphs, and partly to supply a -background for the three chapters that follow. The outstanding features -are broad plateau areas separated by well-defined "Cordilleras." The -plateau divisions are not everywhere of the same origin. Those southwest -of Cuzco (Fig. 130), and in the Anta Basin (Fig. 124), northwest of -Cuzco, are due to prolonged erosion and may be defined as peneplane -surfaces uplifted to a great height. They are now bordered on the one -hand by deep valleys and troughs and basins of erosion and deformation; -and, on the other hand, by residual elevations that owe their present -topography to glacial erosion superimposed upon the normal erosion of -the peneplane cycle. The residuals form true mountain chains like the -Cordillera Vilcanota and Cordillera Vilcapampa; the depressions due to -erosion or deformation or both are either basins like those of Anta and -Cuzco or valleys of the canyon type like the Urubamba canyon; the -plateaus are broad rolling surfaces, the punas of the Peruvian Andes. - -There are two other types of plateaus. The one represents a mature stage -in the erosion cycle instead of an ultimate stage; the other is volcanic -in origin. The former is best developed about Antabamba (Figs. 122 and -123), where again deep canyons and residual ranges form the borders of -the plateau remnants. The latter is well developed above Cotahuasi and -in its simplest form is represented in Fig. 133. Its surface is the top -of a vast accumulation of lavas in places over a mile thick. While rough -in detail it is astonishingly smooth in a broad view (Fig. 29). Above it -rise two types of elevations: first, isolated volcanic cones of great -extent surrounded by huge lava flows of considerable relief; and second, -discontinuous lines of peaks where volcanic cones of less extent are -crowded closely together. The former type is displayed on the Coropuna -Quadrangle, the latter on the Cotahuasi and La Cumbre Quadrangles. - -So high is the elevation of the lava plateau, so porous its soil, so dry -the climate, that a few through-flowing streams gather the drainage of a -vast territory and, as in the Grand Canyon country of our West, they -have at long intervals cut profound canyons. The Arma has cut a deep -gorge at Salamanca; the Cotahuasi runs in a canyon in places 7,000 feet -deep; the Majes heads at the edge of the volcanic field in a steep -amphitheatre of majestic proportions. - -Finally, we have the plateaus of the coastal zone. These are plains with -surfaces several thousand feet in elevation separated by gorges several -thousand feet deep. The Pampa de Sihuas is an illustration. The -post-maturely dissected Coast Range separates it from the sea. The -pampas are in general an aggradational product formed in a past age -before uplift initiated the present canyon cycle of erosion. Other -plateaus of the coastal zone are erosion surfaces. The Tablazo de Ica -appears to be of this type. That at Arica, Chile, near the southern -boundary of Peru, is demonstrably of this type with a border on which -marine planation has in places given rise to a broad terrace -effect.[43] - - - - -CHAPTER XII - -THE WESTERN ANDES: THE MARITIME CORDILLERA OR CORDILLERA OCCIDENTAL - - -The Western or Maritime Cordillera of Peru forms part of the great -volcanic field of South America which extends from Argentina to Ecuador. -On the walls of the Cotahuasi Canyon (Fig. 131), there are exposed over -one hundred separate lava flows piled 7,000 feet deep. They overflowed a -mountainous relief, completely burying a limestone range from 2,000 to -4,000 feet high. Finally, upon the surface of the lava plateau new -mountains were formed, a belt of volcanoes 5,000 feet (1,520 m.) high -and from 15,000 to 20,000 feet (4,570 to 6,100 m.) above the sea. There -were vast mud flows, great showers of lapilli, dust, and ashes, and with -these violent disturbances also came many changes in the drainage. Sixty -miles northeast of Cotahuasi the outlet of an unnamed deep valley was -blocked, a lake was formed, and several hundred feet of sediments were -deposited. They are now wasting rapidly, for they lie in the zone of -alternate freezing and thawing, a thousand feet and more below the -snowline. Some of their bad-land forms look like the solid bastions of -an ancient fortress, while others have the delicate beauty of a Japanese -temple. - -Not all the striking effects of vulcanism belong to the remote geologic -past. A day's journey northeast of Huaynacotas are a group of lakes only -recently hemmed in by flows from the small craters thereabouts. The -fires in some volcanic craters of the Peruvian Andes are still active, -and there is no assurance that devastating flows may not again inundate -the valleys. In the great Pacific zone or girdle of volcanoes the -earth's crust is yet so unstable that earthquakes occur every year, and -at intervals of a few years they have destructive force. Cotahuasi was -greatly damaged in 1912; Abancay is shaken every few years; and the -violent earthquakes of Cuzco and Arequipa are historic. - -On the eastern margin of the volcanic country the flows thin out and -terminate on the summit of a limestone (Cretaceous) plateau. On the -western margin they descend steeply to the narrow west-coast desert. The -greater part of the lava dips beneath the desert deposits; there are a -few intercalated flows in the deposits themselves, and the youngest -flows--limited in number--have extended down over the inner edge of the -desert. - -The immediate coast of southern Peru is not volcanic. It is composed of -a very hard and ancient granite-gneiss which forms a narrow coastal -range (Fig. 171). It has been subjected to very long and continued -erosion and now exhibits mature erosion forms of great uniformity of -profile and declivity. - -From the outcrops of older rocks beneath the lavas it is possible to -restore in a measure the pre-volcanic topography of the Maritime -Cordillera, In its present altitude it ranges from several thousand to -15,000 feet above sea level. The unburied topography has been smoothed -out; the buried topography is rough (Figs. 29 and 166). The contact -lines between lavas and buried surfaces in the deep Majes and Cotahuasi -valleys are in places excessively serrate. From this, it seems safe to -conclude that the period of vulcanism was so prolonged that great -changes in the unburied relief were effected by the agents of erosion. -Thus, while the dominant process of volcanic upbuilding smoothed the -former rough topography of the Maritime Cordillera, erosion likewise -measurably smoothed the present high extra-volcanic relief in the -central and eastern sections. The effect has been to develop a broad and -sufficiently smooth aspect to the summit topography of the entire Andes -to give them a plateau character. Afterward the whole mountain region -was uplifted about a mile above its former level so that at present it -is also continuously lofty. - -The zone of most intense volcanic action does not coincide with the -highest part of the pre-volcanic topography. If the pre-volcanic relief -were even in a very general way like that which would be exhibited if -the lavas were now removed, we should have to say that the chief -volcanic outbursts took place on the western flank of an old and deeply -dissected limestone range. - -[Illustration: FIG. 129--Composition of slopes at Puquiura, Vilcabamba -Valley, elevation 9,000 feet (2,740 m.). The second prominent spur -entering the valley on the left has a flattish top unrelated to the rock -structure. Like the spurs on the right its blunt end and flat top -indicate an earlier erosion cycle at a lower elevation.] - -[Illustration: FIG. 130--Inclined Paleozoic strata truncated by an -undulating surface of erosion at 15,000 feet, southwest of Cuzco.] - -[Illustration: FIG. 131--Terraced valley slopes at Huaynacotas, -Cotahuasi Valley, at 11,500 feet (3,500 m.). Solimana is in the -background. On the floor of the Cotahuasi Canyon fruit trees grow. At -Huaynacotas corn and potatoes are the chief products. The section is -composed almost entirely of lava. There are over a hundred major flows -aggregating 5,000 to 7,000 feet thick.] - -The volume of the lavas is enormous. They are a mile and a half thick, -nearly a hundred miles wide, and of indefinite extent north and south. -Their addition to the Andes, therefore, _has greatly broadened the zone -of lofty mountains_. Their passes are from 2,000 to 3,000 feet higher -than the passes of the eastern Andes. They have a much smaller number of -valleys sufficiently deep to enjoy a mild climate. Their soil is far -more porous and dry. Their vegetation is more scanty. They more than -double the difficulties of transportation. And, finally, their all but -unpopulated loftier expanses are a great vacant barrier between farms in -the warm valleys of eastern Peru and the ports on the west coast. - -The upbuilding process was not, of course, continuous. There were at -times intervals of quiet, and some of them were long enough to enable -streams to become established. Buried valleys may be observed in a -number of places on the canyon walls, where subsequently lava flows -displaced the streams and initiated new drainage systems. In these quiet -intervals the weathering agents attacked the rock surfaces and formed -soil. There were at least three or four such prolonged periods of -weathering and erosion wherein a land surface was exposed for many -thousands of years, stream systems organized, and a cultivable soil -formed. No evidence has been found, however, that man was there to -cultivate the soil. - -The older valleys cut in the quiet period are mere pygmies beside the -giant canyons of today. The present is the time of dominant erosion. The -forces of vulcanism are at last relatively quiet. Recent flows have -occurred, but they are limited in extent and in effects. They alter only -the minor details of topography and drainage. Were it not for the oases -set in the now deep-cut canyon floors, the lava plateau of the Maritime -Cordillera would probably be the greatest single tract of unoccupied -volcanic country in the world. - -The lava plateau has been dissected to a variable degree. Its high -eastern margin is almost in its original condition. Its western margin -is only a hundred miles from the sea, so that the streams have steep -gradients. In addition, it is lofty enough to have a moderate rainfall. -It is, therefore, deeply and generally dissected. Within the borders of -the plateau the degree of dissection depends chiefly upon position with -respect to the large streams. These were in turn located in an -accidental manner. The repeated upbuilding of the surface by the -extensive outflow of liquid rock obliterated all traces of the earlier -drainage. In the Cotahuasi Canyon the existing stream, working down -through a mile of lavas, at last uncovered and cut straight across a -mountain spur 2,000 feet high. Its course is at right angles to that -pursued by the stream that once drained the spur. It is noteworthy that -the Cotahuasi and adjacent streams take northerly courses and join -Atlantic rivers. The older drainage was directly west to the Pacific. -Thus, vulcanism not only broadened the Andes and increased their height, -but also moved the continental divide still nearer the west coast. - -The glacial features of the western or Maritime Cordillera are of small -extent, partly because vulcanism has added a considerable amount of -material in post-glacial time, partly because the climate is so -exceedingly dry that the snowline lies near the top of the country. The -slopes of the volcanic cones are for the most part deeply recessed on -the southern or shady sides. Above 17,500 feet (5,330 m.) the process of -snow and ice excavation still continues, but the tracts that exceed this -elevation are confined to the loftiest peaks or their immediate -neighborhood. There is a distinct difference between the glacial forms -of the eastern or moister and the western or dryer flanks of this -Cordillera. Only peaks like Coropuna and Solimana near the western -border now bear or ever bore snowfields and glaciers. By contrast the -eastern aspect is heavily glaciated. On La Cumbre Quadrangle, there is a -huge glacial trough at 16,000 feet (4,876 m.), and this extends with -ramifications up into the snowfields that formerly included the highest -country. Prolonged glacial erosion produced a full set of topographic -forms characteristic of the work of Alpine glaciers. Thus, each of the -main mountain chains that make up the Andean system has, like the system -as a whole, a relatively more-dry and a relatively less-dry aspect. The -snowline is, therefore, canted from west to east on each chain as well -as on the system. However, this effect is combined with a solar effect -in an unequal way. In the driest places the solar factor is the more -efficient and the snowline is there canted from north to south. - - - - -CHAPTER XIII - -THE EASTERN ANDES: THE CORDILLERA VILCAPAMPA - - -The culminating range of the eastern Andes is the so-called Cordillera -Vilcapampa. Its numerous, sharp, snow-covered peaks are visible in every -summit view from the central portion of the Andean system almost to the -western border of the Amazon basin. Though the range forms a water -parting nearly five hundred miles long, it is crossed in several places -by large streams that flow through deep canyons bordered by precipitous -cliffs. The Urubamba between Torontoy and Colpani is the finest -illustration. For height and ruggedness the Vilcapampa mountains are -among the most noteworthy in Peru. Furthermore, they display glacial -features on a scale unequaled elsewhere in South America north of the -ice fields of Patagonia. - - -GLACIERS AND GLACIAL FORMS - -One of the most impressive sights in South America is a tropical forest -growing upon a glacial moraine. In many places in eastern Bolivia and -Peru the glaciers of the Ice Age were from 5 to 10 miles long--almost -the size of the Mer de Glace or the famous Rhone glacier. In the Juntas -Valley in eastern Bolivia the tree line is at 10,000 feet (3,050 m.), -but the terminal moraines lie several thousand feet lower. In eastern -Peru the glaciers in many places extended down nearly to the tree line -and in a few places well below it. In the Cordillera Vilcapampa vast -snowfields and glacier systems were spread out over a summit area as -broad as the Southern Appalachians. The snowfields have since shrunk to -the higher mountain recesses; the glaciers have retreated for the most -part to the valley heads or the cirque floors; and the lower limit of -perpetual snow has been raised to 15,500 feet. - -[Illustration: FIG. 132--Recessed volcanoes in the right background and -eroded tuffs, ash beds, and lava flows on the left. Maritime Cordillera -above Cotahuasi.] - -[Illustration: FIG. 133--The summit of the great lava plateau above -Cotahuasi on the trail to Antabamba. The lavas are a mile and a half in -thickness. The elevation is 16,000 feet. Hence the volcanoes in the -background, 17,000 feet above sea level, are mere hills on the surface -of the lofty plateau.] - -[Illustration: FIG. 134--Southwestern aspect of the Cordillera -Vilcapampa between Anta and Urubamba from Lake Huaipo. Rugged summit -topography in the background, graded post-mature slopes in the middle -distance, and solution lake in limestone in the foreground.] - -[Illustration: FIG. 135--Summit view, Cordillera Vilcapampa. There are -fifteen glaciers represented in this photograph. The camera stands on -the summit of a minor divide in the zone of nivation.] - -These features are surprising because neither Whymper[44] nor Wolf[45] -mentions the former greater extent of the ice on the volcanoes of -Ecuador, only ten or twelve degrees farther north. Moreover, Reiss[46] -denies that the hypothesis of universal climatic change is supported by -the facts of a limited glaciation in the High Andes of Ecuador; and J. -W. Gregory[47] completely overlooks published proof of the existence of -former more extensive glaciers elsewhere in the Andes: - -"... the absence not only of any traces of former more extensive -glaciation from the tropics, as in the Andes and Kilimandjaro, but also -from the Cape." He says further: "In spite of the extensive glaciers now -in existence on the higher peaks of the Andes, there is practically no -evidence of their former greater extension."(!) - -Whymper spent most of his time in exploring recent volcanoes or those -recently in eruption, hence did not have the most favorable -opportunities for gathering significant data. Reiss was carried off his -feet by the attractiveness of the hypothesis[48] relating to the effect -of glacial denudation on the elevation of the snowline. Gregory appeared -not to have recognized the work of Hettner on the Cordillera of Bogotá -and of Sievers[49] and Acosta on the Sierra Nevada de Santa Marta in -northern Colombia. - -The importance of the glacial features of the Cordillera Vilcapampa -developed on a great scale in very low latitudes in the southern -hemisphere is twofold: first, it bears on the still unsettled problem of -the universality of a colder climate in the Pleistocene, and, second, it -supplies additional data on the relative depression of the snowline in -glacial times in the tropics. Snow-clad mountains near the equator are -really quite rare. Mount Kenia rising from a great jungle on the -equator, Kilimandjaro with its two peaks, Kibo and Mawenzi, two hundred -miles farther south, and Ingomwimbi in the Ruwenzori group thirty miles -north of the equator, are the chief African examples. A few mountains -from the East Indies, such as Kinibalu in Borneo, latitude 6° north, -have been found glaciated, though now without a snow cover. In higher -latitudes evidences of an earlier extensive glaciation have been -gathered chiefly from South America, whose extension 13° north and 56° -south of the equator, combined with the great height of its dominating -Cordillera, give it unrivaled distinction in the study of mountain -glaciation in the tropics. - -Furthermore, mountain summits in tropical lands are delicate climatic -registers. In this respect they compare favorably with the inclosed -basins of arid regions, where changes in climate are clearly recorded in -shoreline phenomena of a familiar kind. Lofty mountains in the tropics -are in a sense inverted basins, the lower snowline of the past is like -the higher shoreline of an interior basin; the terminal moraines and the -alluvial fans in front of them are like the alluvial fans above the -highest strandline; the present snow cover is restricted to mountain -summits of small areal extent, just as the present water bodies are -restricted to the lowest portions of the interior basin; and successive -retreatal stages are marked by terminal moraines in the one case as they -are marked in the other by flights of terraces and beach ridges. - -I made only a rapid reconnaissance across the Cordillera Vilcapampa in -the winter season, and cannot pretend from my limited observations to -solve many of the problems of the field. The data are incorporated -chiefly in the chapter on Glacial Features. In this place it is proposed -to describe only the more prominent glacial features, leaving to later -expeditions the detailed descriptions upon which the solution of some of -the larger problems must depend. - -At Choquetira three prominent stages in the retreat of the ice are -recorded. The lowermost stage is represented by the great fill of -morainic and outwash material at the junction of the Choquetira, and an -unnamed valley farther south at an elevation of 11,500 feet (3,500 m.). -A mile below Choquetira a second moraine appears, elevation 12,000 feet -(3,658 m.), and immediately above the village a third at 12,800 (3,900 -m.). The lowermost moraine is well dissected, the second is ravined and -broken but topographically distinct, the third is sharp-crested and -regular. A fourth though minor stage is represented by the moraine at -the snout of the living glacier and still less important phases are -represented in some valleys--possibly the record of post-glacial changes -of climate. Each main moraine is marked by an important amount of -outwash, the first and third moraines being associated with the greatest -masses. The material in the moraines represents only a part of that -removed to form the successive steps in the valley profile. The -lowermost one has an enormous volume, since it is the oldest and was -built at a time when the valley was full of waste. It is fronted by a -deep fill, over the dissected edge of which one may descend 800 feet in -half an hour. It is chiefly alluvial in character, whereas the next -higher one is composed chiefly of bowlders and is fronted by a -pronounced bowlder train, which includes a remarkable perched bowlder of -huge size. Once the valley became cleaned out the ice would derive its -material chiefly by the slower process of plucking and abrasion, hence -would build much smaller moraines during later recessional stages, even -though the stages were of equivalent length. - -[Illustration: FIG. 136--Glacial sculpture on the southwestern flank of -the Cordillera Vilcapampa. Flat-floored valleys and looped terminal -moraines below and glacial steps and hanging valleys are characteristic. -The present snowfields and glaciers are shown by dotted contours.] - -There is a marked difference in the degree of dissection of the -moraines. The lowermost and oldest is so thoroughly dissected as to -exhibit but little of its original surface. The second has been greatly -modified, but still possesses a ridge-like quality and marks the -beginning of a noteworthy flattening of the valley gradient. The third -is as sharp-crested as a roof, and yet was built so long ago that the -flat valley floor behind it has been modified by the meandering stream. -From this point the glacier retreated up-valley several miles -(estimated) without leaving more than the thinnest veneer on the valley -floor. The retreat must, therefore, have been rapid and without even -temporary halts until the glacier reached a position near that occupied -today. Both the present ice tongues and snowfields and those of a past -age are emphasized by the presence of a patch of scrub and woodland that -extends on the north side of the valley from near the snowline down over -the glacial forms to the lower valley levels. - -The retreatal stages sketched above would call for no special comment if -they were encountered in mountains in northern latitudes. They would be -recognized at once as evidence of successive periodic retreats of the -ice, due to successive changes in temperature. To understand their -importance when encountered in very low latitudes it is necessary to -turn aside for a moment and consider two rival hypotheses of glacial -retreat. First we have the hypothesis of periodic retreat, so generally -applied to terminal moraines and associated outwash in glaciated -mountain valleys. This implies also an advance of the ice from a higher -position, the whole taking place as a result of a climatic change from -warmer to colder and back again to warmer. - -[Illustration: FIG. 137--Looking up a spurless flat-floored glacial -trough near the Chucuito pass in the Cordillera Vilcapampa from 14,200 -feet (4,330 m.). Note the looped terminal and lateral moraines on the -steep valley wall on the left. A stone fence from wall to wall serves to -inclose the flock of the mountain shepherd.] - -[Illustration: FIG. 138--Terminal moraine in the glaciated Choquetira -Valley below Choquetira. The people who live here have an abundance of -stones for building corrals and stone houses. The upper edge of the -timber belt (cold timber line) is visible beyond the houses. Elevation -12,100 feet (3,690 m.).] - -But evidences of more extensive mountain glaciation in the past do not -in themselves prove a change in climate over the whole earth. In an -epoch of fixed climate a glacier system may so deeply and thoroughly -erode a mountain mass, that the former glaciers may either diminish in -size or disappear altogether. As the work of excavation proceeds, the -catchment basins are sunk to, and at last below, the snowline; broad -tributary spurs whose snows nourish the glaciers, may be reduced to -narrow or skeleton ridges with little snow to contribute to the valleys -on either hand; the glaciers retreat and at last disappear. There -would be evidences of glaciation all about the ruins of the former -loftier mountain, but there would be no living glaciers. And yet the -climate might remain the same throughout. - -It is this "topographic" hypothesis that Reiss and Stübel accept for the -Ecuadorean volcanoes. Moreover, the volcanoes of Ecuador are practically -on the equator--a very critical situation when we wish to use the facts -they exhibit in the solution of such large problems as the -contemporaneous glaciation of the two hemispheres, or the periodic -advance and retreat of the ice over the whole earth. This is not the -place to scrutinize either their facts or their hypothesis, but I am -under obligations to state very emphatically that the glacial features -of the Cordillera Vilcapampa require the climatic and not the -topographic hypothesis. Let us see why. - -The differences in degree of dissection and the flattening gradient -up-valley that we noted in a preceding paragraph leave no doubt that -each moraine of the bordering valleys in the Vilcapampa region, -represents a prolonged period of stability in the conditions of -topography as well as of temperature and precipitation. If change in -topographic conditions is invoked to explain retreat from one position -to the other there is left no explanation of the periodicity of retreat -which has just been established. If a period of cold is inaugurated and -glaciers advance to an ultimate position, they can retreat only through -change of climate effected either by general causes or by topographic -development to the point where the snowfields become restricted in size. -In the case of climatic change the ice changes are periodic. In the case -of retreat due to topographic change there should be a steady or -non-periodic falling back of the ice front as the catchment basins -decrease in elevation and the snow-gathering ridges tributary to them -are reduced in height. - -Further, the matterhorns of the Cordillera Vilcapampa are not bare but -snow-covered, vigorous glaciers several miles in length and large -snowfields still survive and the divides are not arêtes but broad -ridges. In addition, the last two moraines, composed of very loose -material, are well preserved. They indicate clearly that the time since -their formation has witnessed no wholesale topographic change. If (1) no -important topographic changes have taken place, and (2) a vigorous -glacier lay for a long period back of a given moraine, and (3) _suddenly -retreated several miles and again became stable_, we are left without -confidence in the application of the topographic hypothesis to the -glacial features of the Vilcapampa region. Glacial retreat may be -suddenly begun in the case of a late stage of topographic development, -but it should be an orderly retreat marked by a large number of small -moraines, or at least a plentiful strewing of the valley floor with -débris. - -[Illustration: FIG. 139--Glacial features on the eastern slopes of the -Cordillera Vilcapampa.] - -The number of moraines in the various glaciated valleys of the -Cordillera Vilcapampa differ, owing to differences in elevation and to -the variable size of the catchment basins. All valleys, however, display -the same sudden change from moraine to moraine and the same -characteristics of gradient. In all of them the lowermost moraine is -always more deeply eroded than the higher moraines, in all of them -glacial erosion was sufficiently prolonged greatly to modify the valley -walls, scour out lake basins, or broad flat valley floors, develop -cirques, arêtes, and pinnacled ridges in limited number. In some, -glaciation was carried to the point where only skeleton divides -remained, in most places broad massive ridges or mountain knots persist. -In spite of all these differences successive moraines were formed, -separated by long stretches either thinly covered with till or exposing -bare rock. - -In examining this group of features it is important to recognize the -essential fact that though the number of moraines varies from valley to -valley, the differences in character between the moraines at low and at -high elevations in a single valley are constant. It is also clear that -everywhere the ice retreated and advanced periodically, no matter with -what topographic features it was associated, whether those of maturity -or of youth in the glacial cycle. We, therefore, conclude that -topographic changes had no significant part to play in the glacial -variations in the Cordillera Vilcapampa. - -The country west of the Cordillera Vilcapampa had been reduced to early -topographic maturity before the Ice Age, and then uplifted with only -moderate erosion of the masses of the interfluves. That on the east had -passed through the same sequence of events, but erosion had been carried -much farther. The reason for this is found in a strong climatic -contrast. The eastern is the windward aspect and receives much more rain -than the western. Therefore, it has more streams and more rapid -dissection. The result was that the eastern slopes were cut to pieces -rapidly after the last great regional uplift; the broad interfluves were -narrowed to ridges. The region eastward from the crest of the Cordillera -to the Pongo de Mainique looks very much like the western half of the -Cascade Mountains in Oregon--the summit tracts of moderate declivity are -almost all consumed. - -The effect of these climatic and topographic contrasts is manifested in -strong contrasts in the position and character of the glacial forms on -the opposite slopes of the range. At Pampaconas on the east the -lowermost terminal moraine is at least a thousand feet below timber -line. Between Vilcabamba pueblo and Puquiura the terminal moraine lies -at 11,200 feet (3,414 m.). By contrast the largest Pleistocene glacier -on the western slope, nearly twelve miles long, and the largest along -the traverse, ended several miles below Choquetira at 11,500 feet (3,504 -m.) elevation, or just at the timber line. Thus, the steeper descents of -the eastern side of the range appear to have carried short glaciers to -levels far lower than those attained by the glaciers of the western -slope. - -It seems at first strange that the largest glaciers were west of the -divide between the Urubamba and the Apurimac, that is, on the relatively -dry side of the range. The reason lies in a striking combination of -topographic and climatic conditions. Snow is a mobile form of -precipitation that is shifted about by the wind like a sand dune in the -desert. It is not required, like water, to begin a downhill movement as -soon as it strikes the earth. Thus, it is a noteworthy fact that snow -drifting across the divides may ultimately cause the largest snowfields -to lie where the least snow actually falls. This is illustrated in the -Bighorns of Wyoming and others of our western ranges. It is, however, -not the wet snow near the snowline, but chiefly the dry snow of higher -altitudes that is affected. What is now the dry or leeward side of the -Cordillera appears in glacial times to have actually received more snow -than the wet windward side. - -[Illustration: FIG. 140--Glacial sculpture in the heart of the -Cordillera Vilcapampa. In places the topography has so high a relief -that the glaciers seem almost to overhang the valleys. See Figs. 96 and -179 for photographs.] - -The topography conspired to increase this contrast. In place of many -streams, direct descents, a dispersion of snow in many valleys, as on -the east, the western slopes had indirect descents, gentler valley -profiles, and that higher degree of concentration of drainage which -naturally goes with topographic maturity. For example, there is nothing -in the east to compare with the big spurless valley near the pass above -Arma. The side walls were so extensively trimmed that the valley was -turned into a trough. The floor was smoothed and deepened and all the -tributary glaciers were either left high up on the bordering slopes or -entered the main valley with very steep profiles; their lateral and -terminal moraines now hang in festoons on the steep side walls. -Moreover, the range crest is trimmed from the west so that the serrate -skyline is a feature rarely seen from eastern viewpoints. This may not -hold true for more than a small part of the Cordillera. It was probably -emphasized here less by the contrasts already noted than by the geologic -structure. The eastward-flowing glaciers descended over dip slopes on -highly inclined sandstones, as at Pampaconas. Those flowing westward -worked either in a jointed granite or on the outcropping _edges_ of the -sandstones, where the quarrying process known as glacial plucking -permitted the development of excessively steep slopes. - -There are few glacial steps in the eastern valleys. The western valleys -have a marvelous display of this striking glacial feature. The -accompanying hachure maps show them so well that little description is -needed. They are from 50 to 200 feet high. Each one has a lake at its -foot into which the divided stream trickles over charming waterfalls. -All of them are clearly associated with a change in the volume of the -glacier that carved the valley. Wherever a tributary glacier entered, or -the side slopes increased notably in area, a step was formed. By retreat -some of them became divided, for the process once begun would push the -step far up valley after the manner of an extinguishing waterfall. - -The retreat of the steps, the abrasion of the rock, and the sapping of -the cirques at the valley heads excavated the upper valleys so deeply -that they are nearly all, as W. D. Johnson has put it, "down at the -heel." Thus, above Arma, one plunges suddenly from the smooth, grassy -glades of the strongly glaciated valley head down over the outer slopes -of the lowermost terminal moraine to the steep lower valley. Above the -moraine are fine pastures, in the steep valley below are thickets and -rocky defiles. There are long quiet reaches in the streams of the -glaciated valley heads besides pretty lakes and marshes. Below, the -stream is swift, almost torrential. Arma itself is built upon alluvial -deposits of glacial origin. A mile farther down the valley is -constricted and steep-walled--really a canyon. - -Though the glaciers have retreated to the summit region, they are by no -means nearing extinction. The clear blue ice of the glacier descending -from Mt. Soiroccocha in the Arma Valley seems almost to hang over the -precipitous valley border. In curious contrast to its suggestion of cold -and storm is the patch of dark green woodland which extends right up to -its border. An earthquake might easily cause the glacier to invade the -woodland. Some of the glaciers between Choquetira and Arma rest on -terminal moraines whose distal faces are from 200 to 300 feet high. The -ice descending southeasterly from Panta Mt. is a good illustration. -Earlier positions of the ice front are marked by equally large moraines. -The one nearest that engaged by the living glacier confines a large lake -that discharges through a gap in the moraine and over a waterfall to the -marshy floor of the valley. - -Retreat has gone so far, however, that there are only a few large -glacier systems. Most of the tributaries have withdrawn toward their -snowfields. In place of the twenty distinct glaciers now lying between -the pass and the terminal moraine below Choquetira, there was in glacial -times one great glacier with twenty minor tributaries. The cirques now -partly filled with damp snow must then have been overflowing with dry -snow above and ice below. Some of the glaciers were over a thousand feet -thick; a few were nearly two thousand feet thick, and the cirques that -fed them held snow and ice at least a half mile deep. Such a remarkably -complete set of glacial features only 700 miles from the equator is -striking evidence of the moist climate on the windward eastern part of -the great Andean Cordillera, of the universal change in climate in the -glacial period, and of the powerful dominating effects of ice erosion in -this region of unsurpassed Alpine relief. - - -THE VILCAPAMPA BATHOLITH AND ITS TOPOGRAPHIC EFFECTS - -[Illustration: FIG. 141--Composite geologic section on the northeastern -border of the Cordillera Vilcapampa, in the vicinity of Pampaconas, to -show the deformative effects of the granite intrusion. There is a -limited amount of limestone near the border of the Cordillera. Both -limestone and sandstone are Carboniferous. See Appendix B. See also -Figs. 142 and 146. The section is about 15 miles long.] - -The main axis of the Cordillera Vilcapampa consists of granite in the -form of a batholith between crystalline schists on the one hand -(southwest), and Carboniferous limestones and sandstones and Silurian -shales and slates on the other (northeast). It is not a domal uplift in -the region in which it was observed in 1911, but an axial intrusion, in -places restricted to a narrow belt not more than a score of miles -across. As we should expect from the variable nature of the invaded -material, the granite belt is not uniform in width nor in the character -of its marginal features. In places the intrusion has produced -strikingly little alteration of the country rock; in other localities -the granite has been injected into the original material in so intimate -a manner as almost completely to alter it, and to give rise to a very -broad zone of highly metamorphosed rock. Furthermore, branches were -developed so that here and there tributary belts of granite extend from -the main mass to a distance of many miles. Outlying batholiths occur -whose common petrographic character and similar manner of occurrence -leave little doubt that they are related abyssally to a common plutonic -mass. - -The Vilcapampa batholith has two highly contrasted borders, whether we -consider the degree of metamorphism of the country rock, the definition -of the border, or the resulting topographic forms. On the northeastern -ridge at Colpani the contact is so sharp that the outstretched arms in -some places embrace typical granite on the one hand and almost -unaltered shales and slates on the other. Inclusions or xenoliths of -shale are common, however, ten and fifteen miles distant, though they -are prominent features in a belt only a few miles wide. The lack of more -intense contact effects is a little remarkable in view of the altered -character of the inclusions, all of which are crystalline in contrast to -the fissile shales from which they are chiefly derived. Inclusions -within a few inches of the border fall into a separate class, since they -show in general but trifling alteration and preserve their original -cleavage plains. It appears that the depth of the intrusion must have -been relatively slight or the intrusion sudden, or both shallow and -sudden, conditions which produce a narrow zone of metamorphosed material -and a sharp contact. - -[Illustration: FIG. 142--The deformative effects of the Vilcapampa -intrusion on the northeastern border of the Cordillera. The deformed -strata are heavy-bedded sandstones and shales and the igneous rocks are -chiefly granites with bordering porphyries. Looking northwest near -Puquiura. For conditions near Pampaconas, looking in the opposite -direction, see Fig. 141. For conditions on the other side of the -Cordillera, see Fig. 146.] - -The relation between shale and granite at Colpani is shown in Fig. 143. -Projections of granite extend several feet into the shale and slate and -generally end in blunt barbs or knobs. In a few places there is an -intimate mixture of irregular slivers and blocks of crystallized -sediments in a granitic groundmass, with sharp lines of demarcation -between igneous and included material. The contact is vertical for at -least several miles. It is probable that other localities on the contact -exhibit much greater modification and invasion of the weak shales and -slates, but at Colpani the phenomena are both simple and restricted in -development. - -[Illustration: FIG. 143--Relation of granite intrusion to schist on the -northeastern border of the Vilcapampa batholith near the bridge of -Colpani, lower end of the granite Canyon of Torontoy. The sections are -from 15 to 25 feet high and represent conditions at different levels -along the well-defined contact.] - -The highly mineralized character of the bordering sedimentary strata, -and the presence of numbers of complementary dikes, nearly identical in -character to those in the parent granite now exposed by erosion over a -broad belt roughly parallel to the contact, supplies a basis for the -inference that the granite may underlie the former at a slight depth, or -may have had far greater metamorphic effects upon its sedimentary roof -than the intruded granite has had upon its sedimentary rim. - -The physiographic features of the contact belt are of special interest. -No available physiographic interpretation of the topography of a -batholith includes a discussion of those topographic and drainage -features that are related to the lithologic character of the intruded -rock, the manner of its intrusion, or the depth of erosion since -intrusion. Yet each one of these factors has a distinct topographic -effect. We shall, therefore, turn aside for a moment from the detailed -discussion of the Vilcapampa region to an examination of several -physiographic principles and then return to the main theme for -applications. - -It is recognized that igneous intrusions are of many varieties and that -even batholithic invasions may take place in rather widely different -ways. Highly heated magmas deeply buried beneath the earth's surface -produce maximum contact effects, those nearer the surface may force the -strata apart without extreme lithologic alterations of the displaced -beds, while through the stoping process a sedimentary cover may be -largely absorbed and the magmas may even break forth at the surface as -in ordinary vulcanism. If the sedimentary beds have great vertical -variation in resistance, in attitude, and in composition, there may be -afforded an opportunity for the display of quite different effects at -different levels along a given contact, so that a great variety of -physical conditions will be passed by the descending levels of erosion. -At one place erosion may have exposed only the summit of the batholith, -at another the associated dikes and sheets and ramifying branches may be -exposed as in the zone of fracture, at a third point the original zone -of flowage may be reached with characteristic marginal schistosity, -while at still greater depths there may be uncovered a highly -metamorphosed rim of resistant sedimentary rock. - -The mere enumeration of these variable structural features is sufficient -to show how variable we should expect the associated land forms to be. -Were the forms of small extent, or had they but slight distinction upon -comparison with other erosional effects, they would be of little -concern. They are, on the contrary, very extensively developed; they -affect large numbers of lofty mountain ranges besides still larger areas -of old land masses subjected to extensive and deep erosion, thus laying -bare many batholiths long concealed by a thick sedimentary roof. - -The differences between intruded and country rock dependent upon these -diversified conditions of occurrence are increased or diminished -according to the history of the region after batholithic invasion takes -place. Regional metamorphism may subsequently induce new structures or -minimize the effects of the old. Joint systems may be developed, the -planes widely spaced in one group of rocks giving rise to monolithic -masses very resistant to the agents of weathering, while those of an -adjacent group may be so closely spaced as greatly to hasten the rate of -denudation. There may be developed so great a degree of schistosity in -one rock as to give rise (with vigorous erosion) to a serrate -topography; on the other hand the forms developed on the rocks of a -batholith may be massive and coarse-textured. - -To these diversifying conditions may be added many others involving a -large part of the field of dynamic geology. It will perhaps suffice to -mention two others: the stage of erosion and the special features -related to climate. If a given intrusion has been accompanied by an -important amount of uplift or marginal compression, vigorous erosion may -follow, whereupon a chance will be offered for the development of the -greatest contrast in the degree of boldness of topographic forms -developed upon rocks of unequal resistance. Ultimately these contrasts -will diminish in intensity, as in the case of all regional differences -of relief, with progress toward the end of the normal cycle of erosion. -If peneplanation ensue, only feeble topographic differences may mark -the line of contact which was once a prominent topographic feature. With -reference to the effects of climate it may be said simply that a granite -core of batholithic origin may extend above the snowline or above timber -line or into the timbered belt, whereas the invaded rock may occur -largely below these levels with obvious differences in both the rate and -the kind of erosion affecting the intruded mass. - -[Illustration: FIG. 144--Cliffed canyon wall in the Urubamba Valley -between Huadquiña and Torontoy. There is a descent of nearly 2,000 feet -shown in the photograph and it is developed almost wholly along -successive joint planes.] - -[Illustration: FIG. 145--Another aspect of the canyon wall of Fig. 144. -The almost sheer descents are in contrast with the cliff and platform -type of topography characteristic of the Grand Canyon of Colorado.] - -If we apply the foregoing considerations to the Cordillera Vilcapampa, -we shall find some striking illustrations of the principles involved. -The invasion of the granite was accompanied by moderate absorption of -the displaced rock, and more especially by the marginal pushing aside of -the sedimentary rim. The immediate effect must have been to give both -intruded rock and country rock greater height and marked ruggedness. -There followed a period of regional compression and torsion, and the -development of widespread joint systems with strikingly regular -features. In the Silurian shales and slates these joints are closely -spaced; in the granites they are in many places twenty to thirty feet -apart. The shales, therefore, offer many more points of attack and have -weathered down into a smooth-contoured topography boldly overlooked -along the contact by walls and peaks of granite. _In some cases a canyon -wall a mile high is developed entirely on two or three joint planes -inclined at an angle no greater than 15°._ The effect in the granite is -to give a marked boldness of relief, nowhere more strikingly exhibited -than at Huadquiña, below Colpani, where the foot-hill slopes developed -on shales and slates suddenly become moderate. The river flows from a -steep and all but uninhabited canyon into a broad valley whose slopes -are dotted with the terraced _chacras_, or farms, of the mountain -Indians. - -The Torontoy granite is also homogeneous while the shales and slates -together with their more arenaceous associates occur in alternating -belts, a diversity which increases the points of attack and the -complexity of the forms. Tending toward the same result is the greater -hardness of the granite. The tendency of the granite to develop bold -forms is accelerated in lofty valleys disposed about snow-clad peaks, -where glaciers of great size once existed, and where small glaciers -still linger. The plucking action of ice has an excellent chance for -expression, since the granite may be quarried cleanly without the -production of a large amount of spoil which would load the ice and -diminish the intensity of its plucking action. - -As a whole the Central Andes passed through a cycle of erosion in late -Tertiary time which was interrupted by uplift after the general surface -had been reduced to a condition of topographic maturity. Upon the -granites mature slopes are not developed except under special conditions -(1) of elevation as in the small batholith above Chuquibambilla, and (2) -where the granite is itself bordered by resistant schists which have -upheld the surface over a broad transitional belt. Elsewhere the granite -is marked by exceedingly rugged forms: deep steep-walled canyons, -precipitous cirques, matterhorns, and bold and extended escarpments of -erosion. In the shale belt the trails run from valley to valley in every -direction without special difficulties, but in the granite they follow -the rivers closely or cross the axis of the range by carefully selected -routes which generally reach the limit of perpetual snow. Added interest -attaches to these bold topographic forms because of the ruins now found -along the canyon walls, as at Torontoy, or high up on the summit of a -precipitous spur, as at Machu Picchu near the bridge of San Miguel. - -The Vilcapampa batholith is bordered on the southwest by a series of -ancient schists with which the granite sustains quite different -relations. No sharp dividing line is visible, the granite extending -along the planes of foliation for such long distances as in places to -appear almost interbedded with the schists. The relation is all the more -striking in view of the trifling intrusions effected in the case of the -seemingly much weaker shales on the opposite contact. Nor is the -metamorphism of the invaded rock limited to simple intrusion. For -several miles beyond the zone of intenser effects the schists have been -enriched with quartz to such an extent that their original darker color -has been changed to light gray or dull white. At a distance they may -even appear as homogeneous and light-colored as the granite. At distant -points the schists assume a darker hue and take on the characters of a -rather typical mica schist. - -It is probable that the Vilcapampa intrusion is one of a family of -batholiths which further study may show to extend over a much larger -territory. The trail west of Abancay was followed quite closely and -accidentally crosses two small batholiths of peculiar interest. Their -limits were not closely followed out, but were accurately determined at -a number of points and the remaining portion of the contact inferred -from the topography. In the case of the larger area there may indeed be -a connection westward with a larger mass which probably constitutes the -ranges distant some five to ten miles from the line of traverse. - -[Illustration: FIG. 146--Deformative effects on limestone strata of the -granite intrusion on the southwestern border of the Vilcapampa batholith -above Chuquibambilla. Fig. 147 is on the same border of the batholith -several miles farther northwest. The granite mass on the right is a -small outlier of the main batholith looking south. The limestone is -Cretaceous. See Appendix C for locations.] - -These smaller intrusions are remarkable in that they appear to have been -attended by little alteration of either invading or invaded rock, though -the granites were observed to become distinctly more acid in the contact -zone. Space was made for them by displacing the sedimentary cover and by -a marked shortening of the sedimentary rim through such structures as -overthrust faults and folds. The contact is observable in a highly -metamorphosed belt about twenty feet wide, and for several hundred feet -more the granite has absorbed the limestone in small amounts with the -production of new minerals and the development of a distinctly lighter -color. The deformative effects of the batholithic invasion are shown in -their gross details in Figs. 141, 142, and 146; the finer details of -structure are represented in Fig. 147, which is drawn from a measured -outcrop above Chuquibambilla. - -It will be seen that we have here more than a mere crinkling, such as -the mica schists of the Cordillera Vilcapampa display. The diversified -sedimentary series is folded and faulted on a large scale with broad -structural undulations visible for miles along the abrupt valley walls. -Here and there, however, the strata become weaker generally through the -thinning of the beds and the more rapid alternation of hard and soft -layers, and for short distances they have absorbed notable amounts of -the stresses induced by the igneous intrusions. In such places not only -the structure but the composition of the rock shows the effects of the -intrusion. Certain shales in the section are carbonaceous and in all -observed cases the organic matter has been transformed to anthracite, a -condition generally associated with a certain amount of minute mashing -and a cementation of both limestone and sandstone. - -[Illustration: FIG. 147--Overthrust folds in detail on the southwestern -border of the Vilcapampa batholith near Chuquibambilla. The section is -fifteen feet high. Elevation, 13,100 feet (4,000 m.). For comparison -with the structural effects of the Vilcapampa intrusion on the northeast -see Fig. 142.] - -The granite becomes notably darker on approach to the northeastern -contact near Colpani; the proportion of ferro-magnesian minerals in some -cases is so large as to give a distinctly black color in sharp contrast -to the nearly white granite typical of the central portion of the mass. -Large masses of shale foundered in the invading magma, and upon fusion -gave rise to huge black masses impregnated with quartz and in places -smeared or injected with granite magma. Everywhere the granite is marked -by numbers of black masses which appear at first sight to be -aggregations of dark minerals normal to the granite and due to -differentiation processes at the time of crystallization. It is, -however, noteworthy that these increase rapidly in number on approach to -the contact, until in the last half-mile they appear to grade into the -shale inclusions. It may, therefore, be doubted that they are -aggregations. From their universal distribution, their uniform -character, and their marked increase in numbers on approach to lateral -contacts, it may reasonably be inferred that they represent foundered -masses of country rock. Those distant from present contacts are in -almost all cases from a few inches to a foot in diameter, while on -approach to lateral contacts they are in places ten to twenty feet in -width, as if the smaller areas represented the last remnants of large -inclusions engulfed in the magma near the upper or roof contact. They -are so thoroughly injected with silica and also with typical granite -magma as to make their reference to the country rock less secure on -petrographical than on purely distributional grounds. - -A parallel line of evidence relates to the distribution of complementary -dikes throughout the granite. In the main mass of the batholith the -dikes are rather evenly distributed as to kind with a slight -preponderance of the dark-colored group. Near the contact, however, -aplitic dikes cease altogether and great numbers of melanocratic dikes -appear. It may be inferred that we have in this pronounced condition -suggestions of strong influence upon the final processes of invasion and -cooling of the granite magma, on the part of the country rock detached -and absorbed by the invading mass. It might be supposed that the -indicated change in the character of the complementary dikes could be -ascribed to possible differentiation of the granite magma whereby a -darker facies would be developed toward the Colpani contact. It has, -however, been pointed out already that the darkening of the granite in -this direction is intimately related to a marked increase in the number -of inclusions, leaving little doubt that the thorough digestion of the -smaller masses of detached shales is responsible for the marked increase -in the number and variety of the ferro-magnesian and special contact -minerals. - -Upon the southwestern border of the batholith the number of aplitic -dikes greatly increases. They form prominent features, not only of the -granite, but also of the schists, adding greatly to the strong contrast -between the schist of the border zone and that outside the zone of -metamorphism. In places in the border schists, these are so numerous -that one may count up to twenty in a single view, and they range in size -from a few inches to ten or fifteen feet. The greater fissility of the -schists as contrasted with the shales on the opposite or eastern margin -of the batholith caused them to be relatively much more passive in -relation to the granite magma. They were not so much torn off and -incorporated in the magma, as they were thoroughly injected and -metamorphosed. Added to this is the fact that they are petrographically -more closely allied to the granite than are the shales upon the -northeastern contact. - - - - -CHAPTER XIV - -THE COASTAL TERRACES - - -Along the entire coast of Peru are upraised and dissected terraces of -marine origin. They extend from sea level to 1,500 feet above it, and -are best displayed north of Mollendo and in the desert south of Payta. -The following discussion relates to that portion of the coast between -Mollendo and Camaná. - -At the time of the development of the coastal terraces the land was in a -state of temporary equilibrium, for the terraces were cut to a mature -stage as indicated by the following facts: (1) the terraces have great -width--from one to five and more miles; (2) their inner border is -straight, or, where curves exist, they are broad and regular; (3) the -terrace tops are planed off smoothly so that they now have an even -gradient and an almost total absence of rock stacks or unreduced spurs; -(4) the mature slopes of the Coast Range, strikingly uniform in gradient -and stage of development (Fig. 148), are perfectly organized with -respect to the inner edge of the terrace. They descend gradually to the -terrace margin, showing that they were graded with respect to sea level -when the sea stood at the inner edge of the highest terrace. - -From the composition and even distribution of the thick-bedded Tertiary -deposits of the desert east of the Coast Range, it is concluded that the -precipitation of Tertiary time was greater than that of today (see p. -261). Therefore, if the present major streams reach the sea, it may also -be concluded that those of an earlier period reached the sea, provided -the topography indicates the perfect adjustment of streams to structure. -Lacustrine sediments are absent throughout the Tertiary section. Such -through-flowing streams, discharging on a stable coast, would also have -mature valleys as a consequence of long uninterrupted erosion at a fixed -level. The Majes river must have cut through the Coast Range at Camaná -then as now. Likewise the Vitor at Quilca must have cut straight across -the Coast Range. An examination of the surface leading down from the -Coast Range to the upper edge of these valleys fully confirms this -deduction. Flowing and well-graded slopes descend to the brink of the -inner valley in each case, where they give way to the gorge walls that -continue the descent to the valley floor. - -Confirmatory evidence is found in the wide Majes Valley at Cantas and -Aplao. (See the Aplao Quadrangle for details.) Though the observer is -first impressed with the depth of the valley, its width is more -impressive still. It is also clear that two periods of erosion are -represented on its walls. Above Aplao the valley walls swing off to the -west in a great embayment quite inexplicable on structural grounds; in -fact the floor of the embayment is developed across the structure, which -is here more disordered than usual. The same is true below Cantas, as -seen from the trail, which drops over two scarps to get to the valley -floor. The upper, widely opened valley is correlated with the latter -part of the period in which were formed the mature terraces of the coast -and the mature slopes bordering the larger valleys where they cross the -Coast Range. - -After its mature development the well-graded marine terrace was upraised -and dissected. The deepest and broadest incisions in it were made where -the largest streams crossed it. Shallower and narrower valleys were -formed where the smaller streams that headed in the Coast Range flowed -across it. Their depth and breadth was in general proportional to the -height of that part of the Coast Range in which their headwaters lay and -to the size of their catchment basins. - -When the dissection of the terrace had progressed to the point where -about one-third of it had been destroyed, there came depression and the -deposition of Pliocene or early Pleistocene sands, gravels, and local -clay beds. Everywhere the valleys were partly or wholly filled and over -broad stretches, as in the vicinity of stream mouths and upon lower -portions of the terrace, extensive deposits were laid down. The largest -deposits lie several hours' ride south of Camaná, where locally they -attain a thickness of several hundred feet. Their upper surface was well -graded and they show a prolonged period of deposition in which the -former coastal terrace was all but concealed. - -[Illustration: FIG. 148--The Coast Range between Mollendo and Arequipa -at the end of June, 1911. There is practically no grass and only a few -dry shrubs. The fine network over the hill slopes is composed of -interlacing cattle tracks. The cattle roam over these hills after the -rains which come at long intervals. (See page 141 for description of the -rains and the transformations they effect. For example, in October, -1911, these hills were covered with grass.)] - -[Illustration: FIG. 149--The great marine terrace at Mollendo. See Fig. -150 for profile.] - -The uplift of the coast terrace and its subsequent dissection bring the -physical history down to the present. The uplift was not uniform; three -notches in the terrace show more faintly upon the granite-gneiss where -the buried rock terrace has been swept clean again, more strongly upon -the softer superimposed sands. They lie below the 700-foot contour and -are insignificant in appearance beside the slopes of the Coast Range or -the ragged bluff of the present coast. - -The effect of the last uplift of the coast was to impel the Majes River -again to cut down its lower course nearly to sea level. The Pliocene -terrace deposits are here entirely removed over an area several leagues -wide. In their place an extensive delta and alluvial fan have been -formed. At first the river undoubtedly cut down to base level at its -mouth and deposited the cut material on the sea floor, now shoal, for a -considerable distance from shore. We should still find the river in that -position had other agents not intervened. But in the Pleistocene a great -quantity of waste was swept into the Majes Valley, whereupon aggradation -began; and in the middle and lower valley it has continued down to the -present. - -[Illustration: FIG. 150--Profile of the coastal terraces at Mollendo. At -1, in a tributary gorge, fossiliferous clay occurs at 800 feet elevation -above the sea. At 2 is a characteristic change of profile marking a drop -from a higher to a lower terrace. On the extreme left is the highest -terrace, just under 1,500 feet (460 m.).] - -[Illustration: FIGS. 151-154--These four diagrams represent the physical -history and the corresponding physiographic development of the coastal -region of Peru between Camaná and Mollendo. The sedimentary beds in the -background of the first diagram are hypothetical and are supposed to -correspond to the quartzites of the Majes Valley at Aplao.] - -The effect has been not only the general aggradation of the valley -floor, but also the development of a combined delta and superimposed -alluvial fan at the valley mouth. The seaward extension of the delta has -been hastened by the gradation of the shore between the bounding -headlands, thus giving rise to marine marshes in which every particle of -contributed waste is firmly held. The plain of Camaná, therefore, -includes parts of each of the following: a delta, a superposed alluvial -fan, a salt-water marsh, a fresh-water marsh, a series of beaches, small -amounts of piedmont fringe at the foot of Pliocene deposits once trimmed -by the river and by waves, and extensive tracts of indefinite fill. (See -the Camaná Quadrangle for details.) - -With the coastal conditions now before us it will be possible to attempt -a correlation between the erosion features and the deposits of the coast -and those of the interior. An understanding of the comparisons will be -facilitated by the use of diagrams, Figs. 151-154, and by a series of -concise summary statements. From the relations of the figure it appears -that: - -1. The Tertiary deposits bordering the Majes Valley east of the Coast -Range were in process of deposition when the sea planed the coastal -terrace (Fig. 151). - -2. A broad mature marine terrace without stacks or sharply alternating -spurs and reëntrants (though the rock is a very resistant granite) is -correlated with the mature grades of the Coast Range, with which they -are integrated and with the mature profiles of the main Cordillera. - -3. Such a high degree of topographic organization requires the -dissection in the _late_ stages of the erosion cycle of at least the -inner or eastern border of the piedmont deposits of the desert, largely -accumulated during the _early_ stages of the cycle. - -4. Since the graded slopes of the Coast Range on the one side descend to -a former shore whose elevation is now but 1,500 feet above sea level, -and since only ten to twenty miles inland on the other side of the -range, the same kind of slope extends beneath Tertiary deposits 4,000 -feet above sea level, it appears that aggradation of the outer (or -western) part of the Tertiary deposits on the eastern border of the -Coast Range continued down to the end of the cycle of erosion, though - -5. There must have been an outlet to the sea, since, as we have already -seen, the water supply of the Tertiary was greater than that of today -and the present streams reach the sea. Moreover, the mature upper slopes -and the steep lower slopes of the large valleys make a pronounced -topographic unconformity, showing two cycles of valley development. - -6. Upon uplift of the coast and dissection of the marine terraces at the -foot of the Coast Range, the streams cut deep trenches on the floors of -their former valleys (Fig. 152) and removed (a) large portions of the -coast terrace, and (b) large portions of the Tertiary deposits east of -the Coast Range. - -7. Depression of the coastal terrace and its partial burial meant the -drowning of the lower Majes Valley and its partial filling with marine -and later with terrestrial deposits. It also brought about the partial -filling by stream aggradation of the middle portion of the valley, -causing the valley fill to abut sharply against the steep valley walls. -(See Fig. 155.) - -8. Uplift and dissection of both the terrace and its overlying sediments -would be accompanied by dissection of the former valley fill, provided -that the waste supply was not increased and that the uplift was regional -and approximately equal throughout--not a bowing up of the coast on the -one hand, or an excessive bowing up of the mountains on the other. But -the waste supply has not remained constant, and the uplift has been -greater in the Cordillera than on the coast. Let us proceed to the proof -of these two conclusions, since upon them depends the interpretation of -the later physical history of the coastal valleys. - -[Illustration: FIG. 155--Steep walls in the Majes Valley below Cantas -and the abrupt termination against them of a deep alluvial fill.] - -[Illustration: FIG. 156--Canyon of the Majes River through the Coast -Range north of Camaná. The rock is a granite-gneiss capped by rather -flat-lying sedimentaries.] - -It is known that the Pleistocene was a time of augmented waste delivery. -At the head of the broadly opened Majes Valley there was deposited a -huge mass of extremely coarse waste several hundred feet deep and -several miles long. Forward from it, interstratified with its outer -margin, and continuing the same alluvial grade, is a still greater mass -of finer material which descends to lower levels. The fine material is -deposited on the floor of a valley cut into Tertiary strata, hence it -is younger than the Tertiary. It is now, and has been for some time -past, in process of dissection, hence it was not formed under present -conditions of climate and relief. It is confidently assigned to the -Pleistocene, since this is definitely known to have been a time of -greater precipitation and waste removal on the mountains, and deposition -on the plains and the floors of mountain valleys. Such a conclusion -appears, even on general grounds, to be but a shade less reliable than -if we were able to find in the upper Majes Valley, as in so many other -Andean valleys, similar alluvial deposits interlocked with glacial -moraines and valley trains. - -In regard to the second consideration--the upbowing of the -Cordillera--it may be noted that the valley and slope profiles of the -main Cordillera shown on p. 191, when extended toward the margin of the -mountain belt, lie nearly a mile above the level of the sea on the west -and the Amazon plains on the east. The evidence of regional bowing thus -afforded is checked by the depths of the mountain valleys and the stream -profiles in them. The streams are now sunk from one to three thousand -feet below their former level. Even in the case of three thousand feet -of erosion the stream profiles are still ungraded, the streams -themselves are almost torrential, and from one thousand to three -thousand feet of vertical cutting must still be accomplished before the -profiles will be as gentle and regular as those of the preceding cycle -of erosion, in which were formed the mature slopes now lying high above -the valley floors. - -Further evidence of bowing is afforded by the attitude of the Tertiary -strata themselves, more highly inclined in the case of the older -Tertiary, less highly inclined in the case of the younger Tertiary. It -is noteworthy that the gradient of the present valley floor is -distinctly less than that of the least highly inclined strata. This is -true even where aggradation is now just able to continue, as near the -nodal point of the valley, above Aplao, where cutting ceases and -aggradation begins. (See the Aplao Quadrangle for change of function on -the part of the stream a half mile above Cosos). Such a progressive -steepening of gradients in the direction of the oldest deposits, shows -very clearly a corresponding progression in the growth of the Andes at -intervals throughout the Tertiary. - -Thus we have aggradation in the Tertiary at the foot of the growing -Andes; aggradation in the Pliocene or early Pleistocene on the floor of -a deep valley cut in earlier deposits; aggradation in the glacial epoch; -and aggradation now in progress. Basin deposits within the borders of -the Peruvian Andes are relatively rare. The profound erosion implied by -the development, first of a mature topography across this great -Cordillera, and second of many deep canyons, calls for deposition on an -equally great scale on the mountain borders. The deposits of the western -border are a mile thick, but they are confined to a narrow zone between -the Coast Range and the Cordillera. Whatever material is swept beyond -the immediate coast is deposited in deep ocean water, for the bottom -falls off rapidly. The deposits of the eastern border of the Andes are -carried far out over the Amazon lowland. Those of earlier geologic -periods were largely confined to the mountain border, where they are now -upturned to form the front range of the Andes. The Tertiary deposits of -the eastern border are less restricted, though they appear to have -gathered chiefly in a belt from fifty to one hundred miles wide. - -The deposits of the western border were laid down by short streams -rising on a divide only 100 to 200 miles from the Pacific. Furthermore, -they drain the dry leeward slopes of the Andes. The deposits of the wet -eastern border were made by far larger streams that carry the waste of -nearly the whole Cordillera. Their shoaling effect upon the Amazon -depression must have been a large factor in its steady growth from an -inland sea to a river lowland. - - - - -CHAPTER XV - -PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT - -GENERAL FEATURES - - -In the preceding chapter we employed geologic facts in the determination -of the age of the principal topographic forms. These facts require -further discussion in connection with their closest physiographic allies -if we wish to show how the topography of today originated. There are -many topographic details that have a fundamental relation to structure; -indeed, without a somewhat detailed knowledge of geology only the -broader and more general features of the landscape can be interpreted. -In this chapter we shall therefore refer not to the scenic features as -in a purely topographic description, but to the rock structure and the -fossils. A complete and technical geologic discussion is not desirable, -first, because it should be based upon much more detailed geologic field -work, and second because after all our main purpose is not to discuss -the geologic features _per se_, but the physiographic background which -the geologic facts afford. I make this preliminary observation partly to -indicate the point of view and partly to emphasize the necessity, in a -broad, geographic study, for the reconstruction of the landscapes of the -past. - -The two dominating ranges of the Peruvian Andes, called the Maritime -Cordillera and the Cordillera Vilcapampa, are composed of igneous -rock--the one volcanic lava, the other intrusive granite. The chief rock -belts of the Andes of southern Peru are shown in Fig. 157. The Maritime -Cordillera is bordered on the west by Tertiary strata that rest -unconformably upon Palaeozoic quartzites. It is bordered on the east by -Cretaceous limestones that grade downward into sandstones, shales, and -basal conglomerates. At some places the Cretaceous deposits rest upon -old schists, at others upon Carboniferous limestones and related -strata, upon small granite intrusives and upon old and greatly altered -volcanic rock. - -The Cordillera Vilcapampa has an axis of granitic rock which was thrust -upward through schists that now border it on the west and slates that -now border it on the east. The slate series forms a broad belt which -terminates near the eastern border of the Andes, where the mountains -break down abruptly to the river plains of the Amazon Basin. The -immediate border on the east is formed of vertical Carboniferous -limestones. The narrow foothill belt is composed of Tertiary sandstones -that grade into loose sands and conglomerates. The inclined Tertiary -strata were leveled by erosion and in part overlain by coarse and now -dissected river gravels, probably of Pleistocene age. Well east of the -main border are low ranges that have never been described. They could -not be reached by the present expedition on account of lack of time. On -the extreme western border of that portion of the Peruvian Andes herein -described, there is a second distinct border chain, the Coast Range. It -is composed of granite and once had considerable relief, but erosion has -reduced its former bold forms to gentle slopes and graded profiles. - -The continued and extreme growth of the Andes in later geologic periods -has greatly favored structural and physiographic studies. Successive -uplifts have raised earlier deposits once buried on the mountain flanks -and erosion has opened canyons on whose walls and floors are the clearly -exposed records of the past. In addition there have been igneous -intrusions of great extent that have thrust aside and upturned the -invaded strata exposing still further the internal structures of the -mountains. From sections thus revealed it is possible to outline the -chief events in the history of the Peruvian Andes, though the outline is -still necessarily broad and general because based on rapid -reconnaissance. However, it shows clearly that the landscape of the -present represents but a temporary stage in the evolution of a great -mountain belt. At the dawn of geologic history there were chains of -mountains where the Andes now stand. They were swept away and even their -roots deeply submerged under invading seas. Repeated uplifts of the -earth's crust reformed the ancient chains or created new ones out of the -rock waste derived from them. Each new set of forms, therefore, exhibits -some features transmitted from the past. Indeed, the landscape of today -is like the human race--inheriting much of its character from past -generations. For this reason the philosophical study of topographic -forms requires at least a broad knowledge of related geologic -structures. - -[Illustration: FIG. 157--Outline sketch showing the principal rock belts -of Peru along the seventy-third meridian. They are: _1_, Pleistocene and -Recent gravels and sands, the former partly indurated and slightly -deformed, with the degree of deformation increasing toward the mountain -border (south). _2_, Tertiary sandstones, inclined from 15° to 30° -toward the north and unconformably overlain by Pleistocene gravels. _3_, -fossil-bearing Carboniferous limestones with vertical dip. _4_, -non-fossiliferous slates, shales, and slaty schists (Silurian) with -great variation in degree of induration and in type of structure. South -of the parallel of 13° is a belt of Carboniferous limestones and -sandstones bordering (_5_), the granite axis of the Cordillera -Vilcapampa. For its structural relations to the Cordillera see Figs. 141 -and 142. _6_, old and greatly disturbed volcanic agglomerates, tuffs and -porphyries, and quartzitic schists and granite-gneiss. _7_, principally -Carboniferous limestones north of the axis of the Central Ranges and -Cretaceous limestones south of it. Local granite batholiths in the axis -of the Central Ranges. _8_, quartzites and slates predominating with -thin limestones locally. South of 8 is a belt of shale, sandstone, and -limestone with a basement quartzite appearing on the valley floors. _9_, -a portion of the great volcanic field of the Central Andes and -characteristically developed in the Western or Maritime Cordillera, -throughout northern Chile, western Bolivia, and Peru. At Cotahuasi (see -also Fig. 20) Cretaceous limestones appear beneath the lavas. _10_, -Tertiary sandstones of the coastal desert with a basement of old -volcanics and quartzites appearing on the valley walls. The valley floor -is aggraded with Pleistocene and Recent alluvium. _11_, granite-gneiss -of the Coast Range. _12_, late Tertiary or Pleistocene sands and gravels -deposited on broad coastal terraces. For rock structure and character -see the other figures in this chapter. For a brief designation of index -fossils and related forms see Appendix B. For the names of the drainage -lines and the locations of the principal towns see Figs. 20 and 204.] - - -SCHISTS AND SILURIAN SLATES[50] - -The oldest series of rocks along the seventy-third meridian of Peru -extends eastward from the Vilcapampa batholith nearly to the border of -the Cordillera, Fig. 157. It consists of (1) a great mass of slates and -shales with remarkable uniformity of composition and structure over -great areas, and (2) older schists and siliceous members in restricted -belts. They are everywhere thoroughly jointed; near the batholith they -are also mineralized and altered from their original condition; in a few -places they have been intruded with dikes and other form of igneous -rock. - -The slates and shales underlie known Carboniferous strata on their -eastern border and appear to be a physical continuation of the -fossiliferous slates of Bolivia; hence they are provisionally referred -to the Silurian, though they may possibly be Devonian. Certainly the -known Devonian exceeds in extent the known Silurian in the Central Andes -but its lithological character is generally quite unlike the character -of the slates here referred to the Silurian. The schists are of great -but unknown age. They are unconformably overlain by known Carboniferous -at Puquiura in the Vilcapampa Valley (Fig. 158), and near Chuquibambilla -on the opposite side of the Cordillera Vilcapampa. The deeply weathered -fissile mica schists east of Pasaje (see Appendix C for all locations) -are also unconformably overlain by conglomerate and sandstone of -Carboniferous age. While the schists vary considerably in lithological -appearance and also in structure, they are everywhere the lowest rocks -in the series and may with confidence be referred to the early -Palaeozoic, while some of them may date from the Proteriozoic. - -[Illustration: FIG. 158--Geologic sketch map of the lower Urubamba -Valley. A single traverse was made along the valley, hence the -boundaries are not accurate in detail. They were sketched in along a few -lateral traverses and also inferred from the topography. The country -rock is schist and the granite intruded in it is an arm of the main -granite mass that constitutes the axis of the Cordillera Vilcapampa. The -structure and to some degree the extent of the sandstone on the left are -represented in Figs. 141 and 142.] - -The Silurian beds are composed of shale, sandstone, shaly sandstone, -limestone, and slate with some slaty schist, among which the shales are -predominent and the limestones least important. Near their contact with -the granite the slate series is composed of alternating beds of -sandstone and shale arranged in beds from one to three feet thick. At -Santa Ana they become more fissile and slaty in character and in several -places are quarried and used for roofing. At Rosalina they consist of -almost uniform beds of shale so soft and so minutely and thoroughly -jointed as to weather easily. Under prolonged erosion they have, -therefore, given rise to a well-rounded and soft-featured landscape. -Farther down the Urubamba Valley they again take on the character of -alternating beds of sandstone and shale from a few feet to fifteen and -more feet thick. In places the metamorphism of the series has been -carried further--the shales have become slates and the sandstones have -been altered to extremely resistant quartzites. The result is again -clearly shown in the topography of the valley wall which becomes bold, -inclosing the river in narrow "pongos" or canyons filled with huge -bowlders and dangerous rapids. The hills become mountains, ledges -appear, and even the heavy forest cover fails to smooth out the natural -ruggedness of the landscape. - -It is only upon their eastern border that the Silurian series includes -calcareous beds, and all of these lie within a few thousand yards of the -contact with the Carboniferous limestones and shales. At first they are -thin paper-like layers; nearer the top they are a few inches wide and -finally attain a thickness of ten or twelve feet. The available -limestone outcrops were rigorously examined for fossils but none were -found, although they are lavishly distributed throughout the younger -Carboniferous beds just above them. It is also remarkable that though -the Silurian age of these beds is reasonably inferred they are not -separated from the Carboniferous by an unconformity, at least we could -find none in this locality. The later beds disconformably overlie the -earlier beds, although the sharp differences in lithology and fossils -make it easy to locate the line of separation. The limestone beds of the -Silurian series are extremely compact and unfossiliferous. At least in -this region those of Carboniferous age are friable and the fossils -varied and abundant. The Silurian beds are everywhere strongly inclined -and throughout the eastern half or third of their outcrop in the -Urubamba Valley they are nearly vertical. - -In view of the enormous thickness of the repeated layers of shale and -sandstone this series is of great interest. Added importance attaches to -their occurrence in a long belt from the eastern edge of the Bolivian -highlands northward through Peru and possibly farther. From the fact -that their disturbance has been on broad lines over wide areas with -extreme metamorphism, they are to be separated from the older -mica-schists and the crumpled chlorite schists of Puquiura and Pasaje. -Further reasons for this distinction lie in their lithologic difference -and, to a more important degree, in the strong unconformity between the -Carboniferous and the schists in contrast to the disconformable -relations shown between the Carboniferous and Silurian fifty miles away -at Pongo de Mainique. The mashing and crumpling that the schists have -experienced at Puquiura is so intense, that were they a part of the -Silurian series the latter should exhibit at least a slight unconformity -in relation to the Carboniferous limestones deposited upon them. - -If our interpretation of the relation of the schists to the slates and -shales be correct, we should have a mountain-making period introduced in -pre-Silurian time, affecting the accumulated sediments and bringing -about their metamorphism and crumpling on a large scale. From the -mountains and uplands thus created on the schists, sediments were washed -into adjacent waters and accumulated as even-bedded and extensive sheets -of sands and muds (the present slates, shales, quartzites, etc.). -Nowhere do the sediments of the slate series show a conglomeratic phase; -they are remarkably well-sorted and consist of material disposed with -great regularity. Though they are coarsest at the bottom the lower beds -do not show cross-bedding, ripple marking, or other signs of -shallow-water conditions. Toward the upper part of the series these -features, especially the ripple-marking, make their appearance. During -the deposition of the last third of the series, and again just before -the deposition of the limestone, the beds took on a predominantly -arenaceous character associated with ripple marks and cross-bedding -characteristic of shallow-water deposits. - -In the persistence of arenaceous sediments throughout the series and the -distribution of the ripple marks through the upper third of the beds, we -have a clear indication that the degree of shallowness was sufficient to -bring the bottom on which the sediments accumulated into the zone of -current action and possibly wave action. It is also worth considering -whether the currents involved were not of similar origin to those now a -part of the great counter-clockwise movements in the southern seas. If -so, their action would be peculiarly effective in the wide distribution -of the sediment derived from a land mass on the eastern edge of a -continental coast, since they would spread out the material to a greater -and greater degree as they flowed into more southerly latitudes. Among -geologic agents a broad ocean current of relatively uniform flow would -produce the most uniform effects throughout a geologic period, in which -many thousand feet of clastic sediments were being accumulated. A -powerful ocean current would also work on flats (in contrast to the -gradient required by near-shore processes), and at the same time be of -such deep and steady flow as to result in neither ripple marks nor -cross-bedding. - -The increasing volume of shallow-water sediments of uniform character -near the end of the Silurian, indicates great crustal stability at a -level which brought about neither a marked gain nor loss of material to -the region. At any rate we have here no Devonian sediments, a -characteristic shared by almost all the great sedimentary formations of -Peru. At the beginning of the Carboniferous the water deepened, and -great heavy-bedded limestones appear with only thin shale partings -through a vertical distance of several hundreds of feet. The enormous -volume of Silurian sediments indicates the deep and prolonged erosion of -the land masses then existing, a conclusion further supported (1) by the -extensive development of the Silurian throughout Bolivia as well as -Peru, (2) by the entire absence of coarse material whether at the top or -bottom of the section, and (3) by the very limited extent of older rock -now exposed even after repeated and irregular uplift and deep -dissection. Indeed, from the latter very striking fact, it may be -reasonably argued that in a general way the relief of the country was -reduced to sea level at the close of the Silurian. Over the perfected -grades of that time there would then be afforded an opportunity for the -effective transportation of waste to the extreme limits of the land. - -Further evidence of the great reduction of surface during the Silurian -and Devonian is supplied by the extensive development of the -Carboniferous strata. Their outcrops are now scattered across the higher -portions of the Andean Cordillera and are prevailingly calcareous in -their upper portions. Upon the eastern border of the Silurian they -indicate marine conditions from the opening of the period, but at Pasaje -in the Apurimac Valley they are marked by heavy beds of basal -conglomerate and sandstone, and an abundance of ripple marking and other -features associated with shallow-water and possibly near-shore -conditions. - - -CARBONIFEROUS - -Carboniferous strata are distributed along the seventy-third meridian -and rival in extent the volcanic material that forms the western border -of the Andes. They range in character from basal conglomerates, -sandstones, and shales of limited development, to enormous beds of -extremely resistant blue limestone, in general well supplied with -fossils. On the eastern border of the Andes they are abruptly terminated -by a great fault, the continuation northward of the marginal fault -recognized in eastern Bolivia by Minchin[51] and farther north by the -writer.[52] Coarse red sandstones with conglomeratic phase abut sharply -and with moderate inclination against almost vertical sandstones and -limestones of Carboniferous age. The break between the vertical -limestones and the gently inclined sandstones is marked by a prominent -scarp nearly four thousand feet high (Fig. 159), and the limestone -itself forms a high ridge through which the Urubamba has cut a narrow -gateway, the celebrated Pongo de Mainique. - -[Illustration: FIG. 159--Topographic and structural section at the -northeastern border of the Peruvian Andes. The slates are probably -Silurian, the fossiliferous limestones are known Carboniferous, and the -sandstones are Tertiary grading up to Pleistocene.] - -At Pasaje, on the western side of the Apurimac, the Carboniferous again -appears resting upon the old schists described on p. 236. It is steeply -upturned, in places vertical, is highly conglomeratic, and in a belt a -half-mile wide it forms true badlands topography. It is succeeded by -evenly bedded sandstones of fine and coarse composition in alternate -beds, then follow shales and sandstones and finally the enormous beds of -limestone that characterize the series. The structure is on the whole -relatively simple in this region, the character and attitude of the beds -indicating their accumulation in a nearly horizontal position. Since the -basal conglomerate contains only pebbles and stones derived from the -subjacent schists and does not contain granites like those in the -Cordillera Vilcapampa batholith on the east it is concluded that the -batholithic invasion was accompanied by the compression and tilting of -the Carboniferous beds and that the batholith itself is -post-Carboniferous. From the ridge summits above Huascatay and in the -deep valleys thereabouts the Carboniferous strata may be seen to extend -far toward the west, and also to have great extent north and south. -Because of their dissected, bare, and, therefore, well-exposed condition -they present exceptional opportunities for the study of Carboniferous -geology in central Peru. - -[Illustration: FIG. 160--The deformative effects of the granite -intrusion of the Cordillera Vilcapampa are here shown as transmitted -through ancient schists to the overlying conglomerates, sandstones, and -limestones of Carboniferous age, in the Apurimac Valley at Pasaje.] - -Carboniferous strata again appear at Puquiura, Vilcapampa, and -Pampaconas. They are sharply upturned against the Vilcapampa batholith -and associated volcanic material, chiefly basalt, porphyry, and various -tuffs and related breccias. The Carboniferous beds are here more -arenaceous, consisting chiefly of alternating beds of sandstone and -shale. The lowermost beds, as at Pongo de Mainique, are dominantly -marine, fossiliferous limestone beds having a thickness estimated to be -over two miles. - -From Huascatay westward and southward the Carboniferous is in part -displaced by secondary batholiths of granite, in part cut off or crowded -aside by igneous intrusions of later date, and in still larger part -buried under great masses of Tertiary volcanic material. Nevertheless, -it remains the dominating rock type over the whole stretch of country -from Huascatay to Huancarama. In the northwestern part of the Abancay -sheet its effect on the landscape may be observed in the knife-like -ridge extending from west to east just above Huambo. Above -Chuquibambilla it again outcrops, resting upon a thick resistant -quartzite of unknown age, Fig. 162. It is strongly developed about -Huadquirca and Antabamba and, still associated with a quartzite floor, -it finally disappears under the lavas of the great volcanic field on the -western border of the Andes. Figs. 141 and 142 show its relation to the -invading granite batholiths and Fig. 162 shows further structural -features as developed about Antabamba where the great volcanic field of -the Maritime Cordillera begins. - -[Illustration: FIG. 161--Types of deformation north of Lambrama near -Sotospampa. A dark basaltic rock has invaded both granite-gneiss and -slate. Sills and dikes occur in great numbers. The topographic -depression in the profile is the Lambrama Valley. See the Lambrama -Quadrangle.] - -Both the enormous thickness of the Carboniferous limestone series and -the absence of clastic members over great areas in the upper portion of -the series prove the widespread extent of the Carboniferous seas and -their former occurrence in large interlimestone tracts from which they -have since been eroded. At Puquiura they extend far over the schist, in -fact almost completely conceal it; at Pasaje they formerly covered the -mica-schists extensively, their erosion in both cases being conditioned -by the pronounced uplift and marginal deformation which accompanied the -development of the Vilcapampa batholith. - -[Illustration: FIG. 162--Sketch sections at Antabamba to show (a) -deformed limestones on the upper edge of the geologic map, Fig. 163 A; -and (b) the structural relations of limestone and quartzite. See also -Fig. 163.] - -The degree of deformation of the Carboniferous sediments varies between -simple uplift through moderate folding and complex disturbances -resulting in nearly vertical attitudes. The simplest structures are -represented at Pasaje, where the uplift of the intruded schists, -marginal to the Vilcapampa batholith, has produced an enormous -monoclinal fold exposing the entire section from basal conglomerates and -sandstones to the thickest limestone. Above Chuquibambilla the -limestones have been uplifted and very gently folded by the invasion of -granite associated with the main batholith and several satellitic -batholiths of limited extent. A higher degree of complexity is shown at -Pampaconas (Fig. 141), where the main monoclinal fold is traversed -almost at right angles by secondary folds of great amplitude. The -limestones are there carried to the limit of the winter snows almost at -the summit of the Cordillera. The crest of each secondary anticline -rises to form a group of conspicuous peaks and tabular ridges. Higher in -the section, as at Puquiura, the sandstones are thrown into a series of -huge anticlines and synclines, apparently by the marginal compression -brought about at the time of the intrusion of the granite core of the -range. At Pongo de Mainique the whole of the visible Carboniferous is -practically vertical, and is cut off by a great fault marking the abrupt -eastern border of the Cordillera. - -[Illustration: FIG. 163--Geologic sketch section to show the relation of -the volcanic flows of Fig. 164 to the sandstones and quartzites -beneath.] - -It is noteworthy that the farther east the Carboniferous extends the -more dominantly marine it becomes, though marine beds of great thickness -constitute a large part of the series in whatever location. From -Huascatay westward the limestones become more and more argillaceous, and -finally give way altogether to an enormous thickness of shales, -sandstones, and thin conglomerates. These were observed to extend with -strong inclination westward out of the region studied and into and under -the volcanoes crowning the western border of the Cordillera. Along the -line of traverse opportunity was not afforded for further study of this -aspect of the series, since our route led generally along the strike -rather than along the dip of the beds. It is interesting to note, -however, that these observations as to the increasing amounts of clastic -material in a westward direction were afterwards confirmed by Señor José -Bravo, the Director of the Bureau of Mines at Lima, who had found -Carboniferous land plants in shales at Pacasmayo, the only fossils of -their kind found in Peru. Formerly it had been supposed that non-marine -Carboniferous was not represented in Peru. From the varied nature of the -flora, the great thickness of the shales in which the specimens were -collected, and the fact that the dominantly marine Carboniferous -elsewhere in Peru is of great extent, it is concluded that the land upon -which the plants grew had a considerable area and probably extended far -west of the present coast line. Since its emergence it has passed -through several orogenic movements. These have resulted in the uplift of -the marine portion of the Carboniferous, while the terrestrial deposits -seem to have all but disappeared in the down-sunken blocks of the ocean -floor, west of the great fault developed along the margin of the -Cordillera. The following figures are graphic representations of this -hypothesis. - -[Illustration: FIG. 164--Geologic sketch map and section, Antabamba -region. The Antabamba River has cut through almost the entire series of -bedded strata]. - -[Illustration: FIG. 165--The upper diagram (A) represents the -hypothetical distribution of land and sea during the Carboniferous -Period, as inferred from the present distribution and character of -Carboniferous limestones and slates. The lower diagram (B) represents -the present relief. The dotted line at the left of the two diagrams -connects identical points. The fragmentation of the former continental -border is believed to have left only a small portion of a former coastal -chain and to have been contemporaneous with the development of ocean -abysses near the present shore.] - -The wide distribution of the Carboniferous sediments and especially the -limestones, together with the uniformity of the fossil faunas, makes it -certain that the sea extended entirely across the region now occupied -by the Andes. However, from the relation of the Carboniferous to the -basal schists, and the most conservative extension of the known -Carboniferous, it may be inferred that the Carboniferous sea did not -completely cover the entire area but was broken here and there by island -masses in the form of an elongated archipelago. The presence of land -plants in the Carboniferous of Pisco warrants the conclusion that a -second island mass, possibly an island chain parallel to the first, -extended along and west of the present shore. - - -CRETACEOUS - -The Cretaceous formations are of very limited extent in the belt of -country under consideration, in spite of their generally wide -distribution in Peru. They are exposed distinctly only on the western -border of the Cordillera and in special relations. In the gorge of -Cotahuasi, over seven thousand feet deep, about two thousand feet of -Cretaceous limestones are exposed. The series includes only a very -resistant blue limestone and terminates abruptly along a well-marked and -highly irregular erosion surface covered by almost a mile of volcanic -material, chiefly lava flows. The character of the bottom of the section -is likewise unknown, since it lies apparently far below the present -level of erosion. - -[Illustration: FIG. 166--Geologic sketch map and cross-section in the -Cotahuasi Canyon at Cotahuasi. With a slight gap this figure continues -Fig. 167 to the left. The section represents a spur of the main plateau -about 1,500 feet high in the center of the map.] - -The Cretaceous limestones of the Cotahuasi Canyon are everywhere greatly -and irregularly disturbed. Typical conditions are represented in the -maps and sections, Figs. 166 and 167. They are penetrated and tilted by -igneous masses, apparently the feeders of the great lava sheets that -form the western summit of the Cordillera. From the restricted -development of the limestones along a western border zone it might be -inferred that they represent a very limited marine invasion. It is -certainly clear that great deformative movements were in progress from -at least late Palæozoic time since all the Palæozoic deposits are broken -abruptly down in this direction, and, except for such isolated -occurrences as the land Carboniferous at Pacasmayo, are not found -anywhere in the coastal region today. The Cretaceous is not only limited -within a relatively narrow shore zone, but also, like the Palæozoic, it -is broken down toward the west, not reappearing from beneath the -Tertiary cover of the desert region or upon the granite-gneisses that -form the foundation for all the known sedimentary strata of the -immediate coast. - -[Illustration: FIG. 167--Geologic sketch map and cross-section in the -Cotahuasi Canyon at Taurisma, above Cotahuasi. The relations of -limestone and lava flows in the center of the map and on a spur top near -the canyon floor. Thousands of feet of lava extend upward from the flows -that cap the limestone.] - -From these considerations I think we have a strong suggestion of the -geologic date assignable to the development of the great fault that is -the most strongly marked structural and physiographic feature of the -west coast of South America. Since the development of this fault is so -intimately related to the origin of the Pacific Ocean basin its study is -of special importance. The points of chief interest may be summarized as -follows: - -(1) The character of the land Carboniferous implies a much greater -extent of the land than is now visible. - -(2) The progressive coarsening of the Carboniferous deposits westward -and their land derivation, together with the great thickness of the -series, point to an elevated land mass in process of erosion west of -the series as a whole, that is west of the present coast. - -(3) The restricted development of the Cretaceous seas upon the western -border of the Carboniferous, and the still more restricted development -of the Tertiary deposits between the mountains and the present coast, -point to increasing definition of the submarine scarp through the -Mesozoic and the Tertiary. - -(4) The Tertiary deposits are all clearly derived from the present -mountains and have been washed seaward down slopes with geographic -relations approximately like those of the present. - -(5) From the great width, deep dissection, and subsequent burial of the -Tertiary terraces of the coast, it is clear that the greater part of the -adjustment of the crust to which the bordering ocean basin is due was -accomplished at least by mid-Tertiary time. - -[Illustration: FIG. 168--Composite structure section representing the -succession of rocks in the Urubamba Valley from Urubamba to Torontoy.] - -Aside from the fossiliferous limestones of known Cretaceous age there -have been referred to the Cretaceous certain red sandstones and shales -marked, especially in the central portions of the Cordillera, by the -presence of large amounts of salt and gypsum. These beds were at first -considered Permian, but Steinmann has since found at Potosí related and -similar formations with Cretaceous fossils. In this connection it is -also necessary to add that the great red sandstone series forming the -eastern border of the Andes in Bolivia is of uncertain age and has -likewise been referred to the Cretaceous, though the matter of its age -has not yet been definitely determined. In 1913 I found it appearing in -northwestern Argentina in the Calchaquí Valley in a relation to the main -Andean mass, similar to that displayed farther north. It contains -fossils and its age was, therefore, readily determinable there.[53] - -In the Peruvian field the red beds of questionable age were not examined -in sufficient detail to make possible a definite age determination. They -occur in a great and only moderately disturbed series in the Anta basin -north of Cuzco, but are there not fossiliferous. The northeastern side -of the hill back of Puqura (of the Anta basin: to be distinguished from -Puquiura in the Vilcabamba Valley) is composed largely of rocks of this -class. In a few places their calcareous members have been weathered out -in such a manner as to show karst topography. Where they occur on the -well-drained brow of a bluff the caves are used in place of houses by -Indian farmers. The large and strikingly beautiful Lake Huaipo, ten -miles north of Anta, and several smaller, neighboring lakes, appear to -have originated in solution depressions formed in these beds. - -[Illustration: FIG. 169--The line of unconformity between the igneous -basement rocks (agglomerates at this point) and the quartzites and -sandstones of the Urubamba Valley, between the town of Urubamba and -Ollantaytambo.] - -[Illustration: FIG. 170--The inclined lower and horizontal upper -sandstone on the southeastern wall of the Majes Valley at Hacienda -Cantas. The section is a half-mile high.] - -The structural relation of the red sandstone series to the older rocks -is well displayed about half-way between Urubamba and Ollantaytambo in -the deep Urubamba Valley. The basal rocks are slaty schist and granite -succeeded by agglomerates and basalt porphyries upon whose eroded -surfaces (Fig. 169) are gray to yellow cross-bedded sandstones. Within a -few hundred feet of the unconformity gypsum deposits begin to appear and -increase in number to such an extent that the resulting soil is in -places rendered worthless. Copper-stained bands are also common near the -bottom of the series, but these are confined to the lower beds. Higher -up in the section, for example, just above the gorge between Urubamba -and Ollantaytambo, even-bedded sandstones occur whose most prominent -characteristic is the regular succession of coarse and fine sandstone -beds. Such alternations of character in sedimentary rocks are commonly -marked by alternating shales and sandstones, but in this locality shales -are practically absent. Toward the top of the section gypsum deposits -again appear first as beds and later, as in the case of the hill-slope -on the southern shore of Lake Huaipo, as veins and irregular masses of -gypsum. The top of the deformed Cretaceous (?) is eroded and again -covered unconformably by practically flat-lying Tertiary deposits. - - -TERTIARY - -The Tertiary deposits of the region under discussion are limited to -three regions: (1) the extreme eastern border of the main Cordillera, -(2) intermontane basins, the largest and most important of which are (a) -the Cuzco basin and (b) the Titicaca-Poopó basin on the -Peruvian-Bolivian frontier, and (3) in the west-coast desert and in -places upon the huge terraces that form a striking feature of the -topography of the coast of Peru. - -It has already been pointed out that the eastern border of the -Cordillera is marked by a fault of great but undetermined throw, whose -topographic importance may be estimated from the fact that even after -prolonged erosion it stands nearly four thousand feet high. Cross-bedded -and ripple-marked features and small lenses of conglomerate are common. -The beds now dip at an angle approximately 20° to 50° northward at the -base of the scarp, but have decreasing dip as they extend farther north -and east. It is noteworthy that the deposits become distinctly -conglomeratic as flatter dips are attained, and that there seems to have -been a steady accumulation of detrital material from the mountains for a -long period, since the deposits pass in unbroken succession from the -highly indurated and massive beds of the mountain base to loose -conglomerates that now weather down much like an ordinary gravel bank. -In a few places just below the mouth of the Ticumpinea, logs about six -inches in diameter were observed embeded in the deposits, but these -belong distinctly to the upper horizons. - -The border deposits, though they vary in dip from nearly flat to 50°, -are everywhere somewhat inclined and now lie up to several hundred feet -above the level of the Urubamba River. Their upper surface is moderately -dissected, the degree of dissection being most pronounced where the dips -are steepest and the height greatest. In fact, the attitude of the -deposits and their progressive change in character point toward, if they -do not actually prove, the steady and progressive character of the beds -first deposited and their erosion and redeposition in beds now higher in -the series. - -Upon the eroded upper surfaces of the inclined border deposits, gravel -beds have been laid which, from evidence discussed in a later paragraph, -are without doubt referable to the Pleistocene. These in turn are now -dissected. They do not extend to the highest summits of the deformed -beds but are confined, so far as observations have gone, to elevations -about one hundred feet above the river. From the evidence that the -overlying horizontal beds are Pleistocene, the thick, inclined beds are -referred to Tertiary age, though they are nowhere fossiliferous. - -Observations along the Urubamba River were extended as far northward as -the mouth of the Timpia, one of the larger tributaries. Upon returning -from this point by land a wide view of the country was gained from the -four-thousand-foot ridge of vertical Carboniferous limestone, in which -it appeared that low and irregular strike ridges continue the features -of the Tertiary displayed along the mountain front far northward as well -as eastward, to a point where the higher ridges and low mountains of -older rock again appear--the last outliers of the Andean system in Peru. -Unfortunately time enough was not available for an extension of the trip -to these localities whose geologic characters still remain entirely -unknown. From the topographic aspects of the country, it is, however, -reasonably certain that the whole intervening depression between these -outlying ranges and the border of the main Cordillera, is filled with -inclined and now dissected and partly covered Tertiary strata. The -elevation of the upper surface does not, however, remain the same; it -appears to decrease steadily and the youngest Tertiary strata disappear -from view below the sediments of either the Pleistocene or the present -river gravels. In the more central parts of the depression occupied by -the Urubamba Valley, only knobs or ridges project here and there above -the general level. - - -_The Coastal Tertiary_ - -The Tertiary deposits of the Peruvian desert region southwest of the -Andes have many special features related to coastal deformation, changes -of climate, and great Andean uplifts. They lie between the west coast of -Peru at Camaná and the high, lava-covered country that forms the western -border of the Andes and in places are over a mile thick. They are -non-fossiliferous, cross-bedded, ripple-marked, and have abundant lenses -of conglomerate of all sizes. The beds rest upon an irregular floor -developed upon a varied mass of rocks. In some places the basement -consists of old strata, strongly deformed and eroded. In other places it -consists of a granite allied in character and probably in origin with -the old granite-gneiss of the Coast Range toward the west. Elsewhere the -rock is lava, evidently the earliest in the great series of volcanic -flows that form this portion of the Andes. - -The deposits on the western border of the Andes are excellently exposed -in the Majes Valley, one of the most famous in Peru, though its fame -rests rather upon the excellence and abundance of its vineyards and -wines than its splendid geologic sections. Its head lies near the base -of the snow-capped peaks of Coropuna; its mouth is at Camaná on the -Pacific, a hundred miles north of Mollendo. It is both narrow and deep; -one may ride across its floor anywhere in a half hour. In places it is a -narrow canyon. Above Cantas it is sunk nearly a mile below the level of -the desert upland through which it flows. Along its borders are exposed -basal granites, old sedimentaries, and lavas; inter-bedded with it are -other lavas that lie near the base of the great volcanic series; through -it still project the old granites of the Coast Range; and upon it have -been accumulated additional volcanic rocks, wind-blown deposits, and, -finally, coarse wash formed during the glacial period. From both the -variety of the formations, the small amount of marginal dissection, and -the excellent exposures made possible by the deep erosion and desert -climate, the Majes Valley is one of the most profitable places in Peru -for physiographic and geologic study. - -[Illustration: FIG. 171--Generalized sketch section to show the -structural relations of the Maritime Cordillera, the desert pampas, and -the Coast Range.] - -The most complete succession of strata (Tertiary) occurs just below -Cantas on the trail to Jaguey (Fig. 171). Upon a floor of -granite-gneiss, and alternating beds of quartzite and shale belonging to -an older series, are deposited heavy beds of red sandstone with many -conglomerate lenses. The sandstone strata are measurably deformed and -their upper surfaces moderately dissected. Upon them have been deposited -unconformably a thicker series of deposits, conglomerates, sandstones, -and finer wind-blown material. The basal conglomerate is very -coarse--much like beach material in both structure and composition, and -similar to that along and south of the present coast at Camaná. Higher -in the section the material is prevailingly sandy and is deposited in -regular beds from a few inches to a few feet in thickness. Near the top -of the section are a few hundred feet of strata chiefly wind deposited. -Unconformably overlying the whole series and in sharp contrast to the -fine wind-blown stuff below it, is a third series of coarse deposits -about five hundred feet thick. The topmost material, that forming the -surface of the desert upland, consists of wind-blown sand now shifted by -the wind and gathered into sand dunes or irregular drifts, banks of -white earth, "tierra blanca," and a pebble pavement a few inches thick. - -If the main facts of the above section are now summarized they will -facilitate an understanding of other sections about to be described, -inasmuch as the summary will in a measure anticipate our conclusions -concerning the origin of the deposits and their subsequent history. The -sediments in the Majes Valley between Cantas and Jaguey consist of three -series separated by two unconformities. The lowermost series is evenly -bedded and rather uniform in composition and topographic expression, -standing forth in huge cliffs several hundred feet high on the eastern -side of the valley. This lower series is overlain by a second series, -which consists of coarse conglomerate grading into sand and ultimately -into very fine fluffy wind-deposited sands and silts. The lower series -is much more deformed than the upper, showing that the deforming -movements of later geologic times have been much less intense than the -earlier, as if there had been a fading out or weakening of the deforming -agents. Finally there is a third series several hundred feet thick which -forms the top of the section. - -[Illustration: FIG. 172--Geologic relations of Coast Range, desert -deposits, and Maritime Cordillera at Moquegua, Peru. After G. I. Adams; -Bol. de Minas del Perú, Vol. 2, No. 4, 1906, p. 20.] - -[Illustration: FIG. 173--Sketch section to show structural details on -the walls of the Majes Valley near Aplao, looking south.] - -Three other sections may now be examined, one immediately below Cantas, -one just above, and one opposite Aplao. The section below Cantas is -shown in Fig. 173, and indicates a lower series of red sandstones -crossed by vertical faults and unconformably overlain by nearly -horizontal conglomerates, sandstones, etc., and the whole faulted again -with an inclined fault having a throw of nearly 25°. A white to gray -sandstone unconformably overlying the red sandstone is shown -interpolated between the lowermost and uppermost series, the only -example of its kind, however. No important differences in -lithographical character may be noted between these and the beds of the -preceding section. - -Again just above Cantas on the east side of the valley is a clean -section exposing about two thousand feet of strata in a half mile of -distance. The foundation rocks are old quartzites and shales in -regularly alternating beds. Upon their uneven upper surfaces are several -thousand feet of red sandstones and conglomerates, which are both folded -and faulted with the underlying quartzites. Above the red sandstones is -a thick series of gray sandstones and silts which makes the top of the -section and unconformably overlies the earlier series. - -A similar succession of strata was observed at Aplao, still farther up -the Majes Valley, Fig. 174. A greatly deformed and metamorphosed older -series is unconformably overlaid by a great thickness of younger strata. -The younger strata may be again divided into two series, a lower series -consisting chiefly of red sandstones and an upper consisting of gray to -yellow, and only locally red sands of finer texture and more uniform -composition. The two are separated by an erosion surface and only the -upper series is tilted regionally seaward with faint local deformation; -the lower series is both folded and faulted with overthrusts aggregating -several thousand feet of vertical and a half mile of horizontal -displacement. - -[Illustration: FIG. 174--The structural relations of the strata on the -border of the Majes Valley at Aplao, looking west. Field sketch from -opposite side of valley. Height of section about 3,000 feet; length -about ten miles.] - -The above sections all lie on the eastern side of the Majes Valley. From -the upper edge of the valley extensive views were gained of the strata -on the opposite side, and two sections, though they were not examined at -close range, are at least worth comparing with those already given. From -the narrows below Cantas the structure appears as in Figs. 175-176, and -shows a deforming movement succeeded by erosion in a lower series. The -upper series of sedimentary rock has suffered but slight deformation. A -still more highly deformed basal series occurs on the right of the -section, presumably the older quartzites. At Huancarqui, opposite Aplao, -an extensive view was gained of the western side of the valley, but the -lower Tertiary seems not to be represented here, as the upper undeformed -series rests unconformably upon a tilted series of quartzites and -slates. Farther up the Cantas valley (an hour's ride above Aplao) the -Tertiary rests upon volcanic flows or older quartzites or the -granite-gneiss exposed here and there along the valley floor. - -[Illustration: FIG. 175--Sketch section to show the structural details -of the strata on the south wall of the Majes Valley near Cantas. The -section is two miles long.] - -[Illustration: FIG. 176--Composite geologic section to show the -structural relations of the rocks on the western border of the Maritime -Cordillera. The inclined strata at the right bottom represent older -rocks; in places igneous, in other places sedimentary.] - -In no part of the sedimentaries in the Majes Valley were fossils found, -save in the now uplifted and dissected sands that overlie the upraised -terraces along the coast immediately south of Camaná and also back of -Mollendo. Like similar coastal deposits elsewhere along the Peruvian -littoral, the terrace sands are of Pliocene or early Pleistocene age. -The age of the deposits back of the Coast Range is clearly greater than -that of the coastal deposits, (1) since they involve two unconformities, -a mile or more of sediments, and now stand at least a thousand feet -above the highest Pliocene (or Pleistocene) in the Camaná Valley, and -(2) because the erosion history of the interior sediments may be -correlated with the physiographic history of the coastal terraces and -the correlation shows that uplift and dissection of the terraces and of -the interior deposits went hand in hand, and that the deposits on the -terraces may similarly be correlated with alluvial deposits in the -valley. - -We shall now see what further ground there is for the determination of -the age of these sediments. Just below Chuquibamba, where they first -appear, the sediments rest upon a floor of volcanic and older rock -belonging to the great field now known from evidence in many localities -to have been formed in the early Tertiary, and here known to be -post-Cretaceous from the relations between Cretaceous limestones and -volcanics in the Cotahuasi Valley (see p. 247). Although volcanic flows -were noted interbedded with the desert deposits, these are few in -number, insignificant in volume, and belong to the top of the volcanic -series. The same may be said of the volcanic flows that locally overlie -the desert deposits. We have then definite proof that the sandstones, -conglomerates, and related formations of the Majes Valley and bordering -uplands are older than the Pliocene or early Pleistocene and younger -than the Cretaceous and the older Tertiary lavas. Hence it can scarcely -be doubted that they represent a considerable part of the Tertiary -period, especially in view of the long periods of accumulation which the -thick sediments represent, and the additional long periods represented -by the two well-marked unconformities between the three principal groups -of strata. - -If we now trace the physical history of the region we have first of all -a deep depression between the granite range along the coast and the -western flank of the Andes. Here and there, as in the Vitor, the Majes, -and other valleys, there were gaps through the Coast Range. Nowhere did -the relief of the coastal chain exceed 5,000 feet. The depression had -been partly filled in early geologic (probably early Paleozoic) time by -sediments later deformed and metamorphosed so that they are now -quartzites and shales. The greater resistance of the granite of the -Coast Range resulted in superior relief, while the older deformed -sedimentaries were deeply eroded, with the result that by the beginning -of the Tertiary the basin quality of the depression was again -emphasized. All these facts are expressed graphically in Fig. 171. On -the western flanks of the granite range no corresponding sedimentary -deposits are found in this latitude. The sea thus appears to have stood -farther west of the Coast Range in Paleozoic times than at present. - -[Illustration: FIG. 177--Composite structure section at Aplao.] - -For the later history it is necessary to assemble the various Tertiary -sections described on the preceding pages. First of all we recognize -three quite distinct types of accumulations, for which we shall have to -postulate three sets of conditions and possibly three separate agents. -The first or lowermost consists of even-bedded deposits of red and gray -sandstones, the former color predominating. The material is in general -well-sorted save locally, where lenses and even thin beds of -conglomerate have been developed. There is, however, about the whole -series a uniformity and an orderliness in striking contrast to the -coarse, cross-bedded, and irregular material above the unconformity. On -their northeastern or inner margin the sandstones are notably coarser -and thicker, a natural result of proximity to the mountains, the source -of the material. The general absence of wind-blown deposits is marked; -these occur entirely along the eastern and northern portions of the -deposits and are recognized (1) by their peculiar cross-bedding, and (2) -by the fact that the cross-bedding is directed northeastward in a -direction contrary to the regional dip of the series, a condition -attributable to the strong sea breezes that prevail every afternoon in -this latitude. - -The main body of the material is such as might be deposited on the wide -flood plains of piedmont streams during a period of prolonged erosion -on surrounding highlands that served as the feeding grounds of the -streams. The alternations in the character of the deposits, alternations -which, in a general view, give a banded appearance to the rock, are -produced by successions of beds of fine and coarse material, though all -of it is sandstone. Such successions are probably to be correlated with -seasonal changes in the volume and load of the depositing streams. - -To gain an idea of the conditions of deposition we may take the -character of the sediments as described above, and from them draw -deductions as to the agents concerned and the manner of their action. - -We may also apply to the area the conclusions drawn from the study of -similar deposits now in process of formation. We have between the coast -ranges of northern Chile and the western flanks of the Cordillera -Sillilica, probably the best example of piedmont accumulation in a dry -climate that the west coast of South America affords. - -Along the inner edge of the Desert of Tarapacá, roughly between the -towns of Tarapacá and Quillagua, Chile, the piedmont gravels, sands, -silts, and muds extend for over a hundred miles, flanking the western -Andes and forming a transition belt between these mountains and the -interior basins of the coast desert. The silts and muds constitute the -outer fringe of the piedmont and are interrupted here and there where -sands are blown upon them from the higher portions of the piedmont, or -from the desert mountains and plains on the seaward side. Practically no -rain falls upon the greater part of the desert and the only water it -receives is that borne to it by the piedmont streams in the early -summer, from the rains and melted snows of the high plateau and -mountains to the eastward. These temporary streams spread upon the outer -edge of the piedmont a wide sheet of mud and silt which then dries and -becomes cracked, the curled and warped plates retaining their character -until the next wet season or until covered with wind-blown sand. The -wind-driven sand fills the cracks in the muds and is even drifted under -the edges of the upcurled plates, filling the spaces completely. Over -this combined fluvial and æolian deposit is spread the next layer of -mud, which frequently is less extensive than the earlier deposits, thus -giving abundant opportunity for the observation of the exact manner of -burial of the older sand-covered stratum. - -Now while the alternations are as marked in Peru as in Chile, it is -noteworthy that the Tertiary material in Peru is not only coarse -throughout, even to the farthest limits of the piedmont, but also that -the alternating beds are thick. Moreover, there are only the most feeble -evidences of wind action in the lowermost Tertiary series. I was -prepared to find curled plates, wind-blown sands, and muds and silts, -but they are almost wholly absent. It is, therefore, concluded that the -dryness was far less extreme than it is today and that full streams of -great competency flowed vigorously down from the mountains and carried -their loads to the inner border of the Coast Range and in places to the -sea. - -The fact that the finer material is _sandy_, not clayey or silty, that -it almost equals in thickness the coarser layers, and that its -distribution appears to be co-extensive with the coarser, warrants the -conclusion that it too was deposited by competent streams of a type far -different from the withering streams associated with piedmont deposits -in a thoroughly arid climate like that of today. Both in the second -Tertiary series and on the present surface are such clear examples of -deposits made in a drier climate as to leave little doubt that the -earliest of the Tertiary strata of the Majes Valley were deposited in a -time of far greater rainfall than the present. It is further concluded -that there was increasing dryness, as shown by hundreds of feet of -wind-blown sand near the top of the section. But the growing dryness was -interrupted by at least one period of greater precipitation. Since that -time there has been a return to the dry climate of a former epoch. - -Uplift and erosion of the earliest of the Tertiary deposits of the Majes -Valley is indicated in two ways: (1) by the deformed character of the -beds, and (2) by the ensuing coarse deposits which were derived from the -invigorated streams. Without strong deformations it would not be -possible to assign the increased erosion so confidently to uplift; with -the coarse deposits that succeed the unconformity we have evidence of -accumulation under conditions of renewed uplift in the mountains and of -full streams competent to remove the increasing load. - -It is in the character of the sediments toward the top of the Tertiary -that we have the clearest evidence of progressive desiccation of the -climate of the region. The amount of wind-blown material steadily -increases and the uppermost five hundred feet is composed predominantly, -and in places exclusively, of this material. The evidences of wind -action lie chiefly in the fine (in places fluffy) nature of the -deposits, their uniform character, and in the tangency of the layers -with respect to the surface on which they were deposited. There are -three diagnostic structural features of great importance: the very steep -dip of the fine laminae; the peculiar and harmonious blending of their -contacts; the manner in which the highly inclined laminae cut off and -succeed each other, whereby quite bewildering changes in the direction -of dip of the inclined beds are brought about on any exposed plane. Some -of these features require further discussion. - -It is well known that the front of a sand dune generally consists of -sand deposited on a slope inclined at the angle of repose, say between -30° and 35°, and rolled into place up the long back slope of the dune by -the wind. It has not, however, been generally recognized that the angle -of repose may be exceeded (a) when there exists a strong back eddy or -(b) when the wind blows violently and for a short time in the opposite -direction. In either case sand is carried up the short steep slope of -the dune front and accumulated at an angle not infrequently running up -to 43° and 48° and locally, and under the most favorable circumstances, -in excess of 50°. The conditions under which these steep angles are -attained are undoubtedly not universal, but they can be found in some -parts of almost any desert in the world. They appear not to be present -where the sand grains are of uniform size throughout, since that leads -to rolling. They are found rather where there is a certain limited -variation in size that promotes packing. Packing and the development of -steep slopes are also facilitated in parts of the coastal desert of Peru -by a cloud canopy that hangs over the desert in the early morning, that -in the most favorable places moistens even the dune surfaces and that -has least penetration on the steep semi-protected dune fronts. Sand -later blown up the dune front or rolled down from the dune crest is -encouraged to remain near the cornice on an abnormally steep slope by -the attraction which the slightly moister sand has for the dry grains -blown against it. Since dunes travel and since their front layers, -formed on steep slopes, are cut off to the level of the surface in the -rear of the dune, it follows that the steepest dips in exposed sections -are almost always less than those in existing dunes. Exceptions to the -rule will be noted in filled hollows not re-excavated until deeply -covered by wind-blown material. These, re-exposed at the end of a long -period of wind accumulation, may exhibit even the maximum dips of the -dune cornices. Such will be conspicuously the case in sections in -aggraded desert deposits. On the border of the Majes Valley, from 400 to -500 feet of wind-accumulated deposits may be observed, representing a -long period of successive dune burials. - -The peculiar blending of the contact lines of dune laminae, related to -the tangency commonly noted in dune accumulations, is apparently due to -the fact that the wind does not require a graded surface to work on, but -blows uphill as well as down. It is present on both the back-slope and -the front-slope deposits. Its finest expression appears to be in -districts where the dune material was accumulated by a violent wind -whose effects the less powerful winds could not destroy. - -It is to the ability of the wind to transport material against, as well -as with, gravity, that we owe the third distinct quality of dune -material, the succession of flowing lines, in contrast to the succession -of now flat-lying now steeply inclined beds characteristic of -cross-bedded material deposited by water. One dune travels across the -face of the country only to be succeeded by another.[54] Even if wind -aggradation is in progress, the plain-like surface in the rear of a dune -may be excavated to the level of steeply inclined beds upon whose -truncated outcrop other inclined beds are laid, Fig. 178. The contrast -to these conditions in the case of aggradation by water is so clearly -and easily inferred that space will not be taken to point them out. It -is also true as a corollary to the above that the greater part of a body -of wind-drifted material will consist of cross-bedded layers, and not a -series of evenly divided and alternating flat-lying and cross-bedded -layers which result from deposition in active and variable currents of -water. - -The caution must of course be observed that wind action and water action -may alternate in a desert region, as already described in Tarapacá in -northern Chile, so that the whole of a deposit may exhibit an -alternation of cross-bedded and flat-lying layers; but the former only -are due to wind action, the latter to water action. - -Finally it may be noted that the sudden, frequent, and diversified dips -in the cross-bedding are peculiarly characteristic of wind action. -Although one sees in a given cross-section dips apparently directed only -toward the left or the right, excavation will supply a third dimension -from which the true dips may be either observed or calculated. These -show an almost infinite variety of directions of dip, even in restricted -areas, a condition due to the following causes: - -(1) the curved fronts of sand dunes, which produce dips concentric with -respect to a point and ranging through 180° of arc; (2) the irregular -character of sand dunes in many places, a condition due in turn to (a) -the changeful character of the strong wind (often not the prevailing -wind) to which the formation of the dunes is due, and (b) the influence -of the local topography upon wind directions within short distances or -upon winds of different directions in which a slight change in wind -direction is followed by a large change in the local currents; (3) the -fact that all combinations are possible between the erosion levels of -the wind in successive generations of dunes blown across a given area, -hence _any_ condition at a given level in a dune may be combined with -_any other_ condition of a succeeding dune; (4) variations in the sizes -of successive dunes will lead to further contrasts not only in the -scale of the features but also in the direction and amount of the dips. - -[Illustration: FIG. 178--Plan and cross-sections of superimposed sand -dunes of conventional outline. In the sections, dune _A_ is supposed to -have left only a small basal portion to be covered by dune _B_. In the -same way dune _C_ has advanced to cover both _A_ and _B_. The basal -portions that have remained are exaggerated vertically in order to -display the stratification. It is obviously not necessary that the dunes -should all be of the same size and shape and advancing in the same -direction in order to have the tangential relations here displayed. Nor -need the aggrading material be derived from true dunes. The results -would be the same in the case of sand _drifts_ with their associated -wind eddies. All bedded wind-blown deposits would have the same general -relations. No two successive deposits, no matter from what direction the -successive drifts or dunes travel, would exactly correspond in direction -and amount of dip.] - -Finally, we may note that a section of dune deposits has a distinctive -feature not exhibited by water deposits. If the foreset beds of a -cross-bedded water deposit be exposed in a plane parallel to the strike -of the beds, the beds will appear to be horizontal. They could not then -be distinguished from the truly horizontal beds above and below them. -But the conditions of wind deposition we have just noted, and chiefly -the facts expressed by Fig. 178, make it impossible to select a position -in which both tangency and irregular dips are not well developed in a -wind deposit. I believe that we have in the foregoing facts and -inferences a means for the definite separation of these two classes of -deposits. Difficulties will arise only when there is a quick succession -of wind and water action in time, or where the wind produces powerful -and persistent effects without the actual formation of dunes. - -The latest known deposits in the coastal region are found surmounting -the terrace tops along the coast between Camaná and Quilca, where they -form deposits several hundred feet thick in places. The age of these -deposits is determined by fossil evidence, and is of extraordinary -interest in the determination of the age of the great terraces upon -which they lie. They consist of alternating beds of coarse and fine -material, the coarser increasing in thickness and frequency toward the -bottom of the section. It is also near the bottom of the section that -fossils are now found; the higher members are locally saline and -throughout there is a marked inclination of the beds toward the present -shore. The deposits appear not to have been derived from the underlying -granite-gneiss. They are distributed most abundantly near the mouths of -the larger streams, as near the Vitor at Quilca, and the Majes at -Camaná. Elsewhere the terrace summit is swept clean of waste, except -where local clay deposits lie in the ravines, as back of Mollendo and -where "tierras blancas" have been accumulated by the wind. - -These coastal deposits were laid down upon a dissected terrace up to -five miles in width. The degree of dissection is variable, and depends -upon the relation of the through-flowing streams to the Coast Range. The -Vitor and the Majes have cut down through the Coast Range, and locally -removed the terrace; smaller streams rising on the flanks of the Coast -Range either die out near the foot of the range or cross it in deep and -narrow valleys. The present drainage on the seaward slopes of the Coast -Range is entirely ineffective in reaching the sea, as was seen in 1911, -the wettest season known on the coast in years and one of the wettest -probably ever observed on this coast by man. - -In consequence of their deposition on a terrace that ranges in elevation -from zero to 1,500 feet above sea level, the deposits of the coast are -very irregularly disposed. But in consequence of their great bulk they -have a rather smooth upper surface, gradation having been carried to the -point where the irregularities of the dissected terrace were smoothed -out. Their general uniformity is broken where streams cross them, or -where streams crossed them during the wetter Pleistocene. Their -elevation, several hundred feet above sea level, is responsible for the -deep dissection of their coastal margin, where great cliffs have been -cut. - - -PLEISTOCENE - -The broad regional uplift of the Peruvian Andes in late Tertiary and in -Pleistocene times carried their summits above the level of perpetual -snow. It is still an open question whether or not uplift was -sufficiently great in the early Pleistocene to be influenced by the -first glaciations of that period. As yet, there are evidences of only -two glacial invasions, and both are considered late events on account of -the freshness of their deposits and the related topographic forms. The -coarse deposits--nearly 500 feet thick--that form the top of the desert -section described above clearly indicate a wetter climate than prevailed -during the deposition of the several hundred feet of wind-blown deposits -beneath them. But if our interpretation be correct these deposits are of -late Tertiary age, and their character and position are taken to -indicate climatic changes in the Tertiary. They may have been the mild -precursors of the greater climatic changes of glacial times. Certain it -is that they are quite unlike the mass of the Tertiary deposits. On the -other hand they are separated from the deposits of known glacial age by -a time interval of great length--an epoch in which was cut a benched -canyon nearly a mile deep and three miles wide. They must, therefore, -have been formed when the Andes were thousands of feet lower and unable -to nourish glaciers. It was only after the succeeding uplifts had raised -the mountain crests well above the frost line that the records of -oscillating climates were left in erratic deposits, troughed valleys, -cliffed cirques and pinnacled divides. - -The glacial forms are chiefly at the top of the country; the glacial -deposits are chiefly in the deep valleys that were carved before the -colder climate set in. The rock waste ground up by the ice was only a -small part of that delivered to the streams in glacial times. Everywhere -the wetter climate resulted in the partial stripping of the residual -soil gathered upon the smooth mature slopes formed during the long -Tertiary cycle of erosion. This moving sheet of waste as well as the -rock fragments carried away from the glacier ends were strewn along the -valley floors, forming a deep alluvial fill. Thereby the canyon floors -were rendered habitable. - -In the chapters on human geography we have already called attention to -the importance of the U-shaped valleys carved by the glaciers. Their -floors are broad and relatively smooth. Their walls restrain the live -stock. They are sheltered though lofty. But all the human benefits -conferred by ice action are insignificant beside those due to the -general shedding of waste from the cold upper surfaces to the warm -levels of the valley floors. The alluvium-filled valleys are the seats -of dense populations. In the lowest of them tropical and sub-tropical -products are raised, like sugar-cane and cotton, in a soil that once lay -on the smooth upper slopes of mountain spurs or that was ground fine on -the bed of an Alpine glacier. - -[Illustration: FIG. 179--Snow fields on the summit of the Cordillera -Vilcapampa near Ollantaytambo. A huge glacier once lay in the steep -canyon in the background and descended to the notched terminal moraine -at the canyon mouth. In places the glacier was over a thousand feet -thick. From the terminal moraine an enormous alluvial fan extends -forward to the camera and to the opposite wall of the Urubamba Valley. -It is confluent with other fans of the same origin. See Fig. 180. In the -foreground are flowers, shrubs, and cacti. A few miles below Urubamba at -11,500 feet.] - -[Illustration: FIG. 180--Urubamba Valley between Ollantaytambo and -Torontoy, showing (1) more moderate upper slopes and steeper lower -slopes of the two-cycle mountain spurs; (2) the extensive alluvial -deposits of the valley, consisting chiefly of confluent alluvial fans -heading in the glaciated mountains on the left. See Fig. 179.] - -[Illustration: FIG. 181--Glacial features of the Central Ranges (see -Fig. 204). Huge lateral moraines built by ice streams tributary to the -main valley north of Chuquibambilla. That the tributaries persisted long -after the main valley became free of ice is shown by the descent of the -lateral moraines over the steep border of the main valley and down to -the floor of it.] - -The Pleistocene deposits fall into three well-defined groups: (1) -glacial accumulations at the valley heads, (2) alluvial deposits in -the valleys, and (3) lacustrine deposits formed on the floors of -temporary lakes in inclosed basins. Among these the most variable in -form and composition are the true glacier-laid deposits at the valley -heads. The most extensive are the fluvial deposits accumulated as valley -fill throughout the entire Andean realm. Though important enough in some -respects the lacustrine deposits are of small extent and of rather local -significance. Practically none of them fall within the field of the -present expedition; hence we shall describe only the first two classes. - -The most important glacial deposits were accumulated in the eastern part -of the Andes as a result of greater precipitation, a lower snowline, and -catchment basins of larger area. In the Cordillera Vilcapampa glaciers -once existed up to twelve and fifteen miles in length, and those several -miles long were numerous both here and throughout the higher portions of -the entire Cordillera, save in the belt of most intense volcanic action, -which coincides with the driest part of the Andes, where the glaciers -were either very short or wanting altogether. - -Since vigorous glacial action results in general in the cleaning out of -the valley heads, no deposits of consequence occur in these locations. -Down valley, however, glacial deposits occur in the form of terminal -moraines of recession and ground moraines. The general nature of these -deposits is now so well known that detailed description seems quite -unnecessary except in the case of unusual features. - -It is noteworthy that the moraines decrease in size up valley since each -valley had been largely cleaned out by ice action before the retreat of -the glacier began. Each lowermost terminal moraine is fronted by a great -mass of unsorted coarse bowldery material forming a fill in places -several hundred feet thick, as below Choquetira and in the Vilcapampa -Valley between Vilcabamba and Puquiura. This bowldery fill is quite -distinct from the long, gently inclined, and stratified valley train -below it, or the marked ridge-like moraine above it. It is in places a -good half mile in length. Its origin is believed to be due to an -overriding action beyond the last terminal moraine at a time when the -ice was well charged with débris, an overriding not marked by morainal -accumulations, chiefly because the ice did not maintain an extreme -position for a long period. - -In the vicinity of the terminal moraines the alluvial valley fill is -often so coarse and so unorganized as to look like till in the cut banks -along the streams, though its alluvial origin is always shown by the -topographic form. This characteristic is of special geologic interest -since the form may be concealed through deposition or destroyed by -erosion, and no condition but the structure remain to indicate the -manner of origin of the deposit. In such an event it would not be -possible to distinguish between alluvium and till. The gravity of the -distinction appears when it is known that such apparently unsorted -alluvium may extend for several miles forward of a terminal moraine, in -the shape of a widespreading alluvial fan apparently formed under -conditions of extremely rapid aggradation. I suppose it would not be -doubted in general that a section of such stony, bowldery, unsorted -material two miles long would have other than a glacial origin, yet such -may be the case. Indeed, if, as in the Urubamba Valley, a future section -should run parallel to the valley across the heads of a great series of -fans of similar composition, topographic form, and origin, it would be -possible to see many miles of such material. - -The depth of the alluvial valley fill due to tributary fan accumulation -depends upon both the amount of the material and the form of the valley. -Below Urubamba in the Urubamba Valley a fine series is displayed, as -shown in Fig. 180. The fans head in valleys extending up to snow-covered -summits upon whose flanks living glaciers are at work today. Their heads -are now crowned by terminal moraines and both moraines and alluvial fans -are in process of dissection. The height and extent of the moraines and -the alluvial fans are in rough proportion and in turn reflect the -height, elevation, and extent of the valley heads which served as fields -of nourishment for the Pleistocene glaciers. Where the fans were -deposited in narrow valleys the effect was to increase the thickness of -the deposits at the expense of their area, to dam the drainage lines or -displace them, and to so load the streams that they have not yet -cleared their beds after thousands of years of work under torrential -conditions. - -Below Urubamba the alluvial fans entering the main valley from the east -have pushed the river against its western valley wall, so that the river -flows on one side against rock and on the other against a hundred feet -of stratified material. In places, as at the head of the narrows on the -valley trail to Ollantaytambo, a flood plain has been formed in front of -the scarp cut into the alluvium, while the edge of the dissected -alluvial fans has been sculptured into erosion forms resembling -bad-lands topography. On the western side of the valley the alluvial -fans are very small, since they are due to purely local accumulations of -waste from the edge of the plateau. Glaciation has here displaced the -river. Its effects will long be felt in the disproportionate erosion of -the western wall of the valley. - -By far the most interesting of the deposits of glacial time are those -laid down on the valley floors in the form of an alluvial fill. Though -such deposits have greater thickness as a rule near the nourishing -moraines or bordering alluvial fans at the lower ends of the valleys, -they are everywhere important in amount, distinctive in topographic -form, and of amazingly wide extent. They reach far into and possibly -across the Amazon basin, they form a distinct though small piedmont -fringe along the eastern base of the Andes, and they are universal -throughout the Andean valleys. That a deposit of such volume--many times -greater than all the material accumulated in the form of high-level -alluvial fans or terminal moraines--should originate in a tropical land -in a region that suffered but limited Alpine glaciation vastly increases -its importance. - -[Illustration: FIG. 182--Dissected alluvial fans on the border of the -Urubamba Valley near Hacienda Chinche. A Characteristic feature of the -valleys of the Peruvian Andes below the zone of glaciation but within -the limits of its aggraditional effects. Through alluviation the valleys -and basins of the Andean Cordillera, and vast areas of the great Amazon -plains east of it, felt the effects of the glacial conditions of a past -age.] - -The fill is composed of both fine and coarse material laid down by water -in steep valley floors to a depth of many feet. It breaks the steep -slope of each valley, forming terraces with pronounced frontal scarps -facing the river. On the raw bluffs at the scarps made by the -encroaching stream good exposures are afforded. At Chinche in the -Urubamba Valley above Santa Ana, the material is both sand and clay with -an important amount of gravel laid down with steep valleyward -inclination and under torrential conditions; so that within a given bed -there may be an apparent absence of lamination. Almost identical -conditions are exhibited frequently along the railway to Cuzco in the -Vilcanota Valley. The material is mixed sand and gravel, here and there -running to a bowldery or stony mass where accessions have been received -from some source nearby. It is modified along its margin not only in -topographic form but also in composition by small tributary alluvial -fans, though these in general constitute but a small part of the total -mass. At Cotahuasi, Fig. 29, there is a remarkable fill at least four -hundred feet deep in many places where the river has exposed fine -sections. The depth of the fill is, however, not determined by the -height of the erosion bluffs cut into it, since the bed of the river is -made of the same material. The rock floor of the valley is probably at -least an additional hundred feet below the present level of the river. - -[Illustration: FIG. 183--Two-cycle slopes and alluvial fill between -Iluichihua and Chuquibambilla. The steep slopes on the inner valley -border are in many places vertical and rock cliffs are everywhere -abundant. Mature slopes have their greatest development here between -13,500 and 15,000 feet (4,110 to 4,570 m.). Steepest mature slopes run -from 15° to 21°. Least steep are the almost level spur summits. The -depths of the valley fill must be at least 300, and may possibly be 500 -feet. The break between valley fill and steep slopes is most pronounced -where the river runs along the valley wall or undercuts it; least -pronounced where alluvial fans spread out from the head of some ravine. -It is a bowldery, stony fill almost everywhere terraced and cultivated.] - -Similar conditions are well displayed at Huadquiña, where a fine series -of terraces at the lower end of the Torontoy Canyon break the descent of -the environing slopes; also in the Urubamba Valley below Rosalina, and -again at the edge of the mountains at the Pongo de Mainique. It is -exhibited most impressively in the Majes Valley, where the bordering -slopes appear to be buried knee-deep in waste, and where from any -reasonable downward extension of rock walls of the valley there would -appear to be at least a half mile of it. It is doubtful and indeed -improbable that the entire fill of the Majes Valley is glacial, for -during the Pliocene or early Pleistocene there was a submergence which -gave opportunity for the partial filling of the valley with non-glacial -alluvium, upon which the glacial deposits were laid as upon a flat and -extensive floor that gives an exaggerated impression of their depth. -However, the head of the Majes Valley contains at least six hundred feet -and probably as much as eight hundred feet of alluvium now in process of -dissection, whose coarse texture and position indicates an origin under -glacial conditions. The fact argues for the great thickness of the -alluvial material of the lower valley, even granting a floor of Pliocene -or early Pleistocene sediments. The best sections are to be found just -below Chuquibamba and again about halfway between that city and Aplao, -whereas the best display of the still even-floored parts of the valley -are between Aplao and Cantas, where the braided river still deposits -coarse gravels upon its wide flood plain. - - - - -CHAPTER XVI - -GLACIAL FEATURES - -THE SNOWLINE - - -South America is classical ground in the study of tropical snowlines. -The African mountains that reach above the snowline in the equatorial -belt--Ruwenzori, Kibo, and Kenia--have only been studied recently -because they are remote from the sea and surrounded by bamboo jungle and -heavy tropical forest. On the other hand, many of the tropical mountains -of South America lie so near the west coast as to be visible from it and -have been studied for over a hundred years. From the days of Humboldt -(1800) and Boussingault (1825) down to the present, observations in the -Andes have been made by an increasing number of scientific travelers. -The result is a large body of data upon which comparative studies may -now be profitably undertaken. - -Like scattered geographic observations of many other kinds, the earlier -studies on the snowline have increased in value with time, because the -snowline is a function of climatic elements that are subject to periodic -changes in intensity and cannot be understood by reference to a single -observation. Since the discovery of physical proofs of climatic changes -in short cycles, studies have been made to determine the direction and -rate of change of the snowline the world over, with some very striking -results. - -It has been found[55] that the changes run in cycles of from thirty to -thirty-five years in length and that the northern and southern -hemispheres appear to be in opposite phase. For example, since 1885 the -snowline in the southern hemisphere has been decreasing in elevation in -nine out of twelve cases by the average amount of nine hundred feet. -With but a single exception, the snowline in the northern hemisphere -has been rising since 1890 with an average increase of five hundred feet -in sixteen cases. To be sure, we must recognize that the observations -upon which these conclusions rest have unequal value, due both to -personal factors and to differences in instrumental methods, but that in -spite of these tendencies toward inequality they should agree in -establishing a general rise of the snowline in the northern hemisphere -and an opposite effect in the southern is of the highest significance. - -It must also be realized that snowline observations are altogether too -meager and scattered in view of the abundant opportunities for making -them, that they should be standardized, and that they must extend over a -much longer period before they attain their full value in problems in -climatic variations. Once the possible significance of snowline changes -is appreciated the number and accuracy of observations on the elevation -and local climatic relations of the snowline should rapidly increase. - -In 1907 I made a number of observations on the height of the snowline in -the Bolivian and Chilean Andes between latitudes 17° and 20° south, and -in 1911 extended the work northward into the Peruvian Andes along the -seventy-third meridian. It is proposed here to assemble these -observations and, upon comparison with published data, to make a few -interpretations. - -From Central Lagunas, Chile, I went northeastward via Pica and the -Huasco Basin to Llica, Bolivia, crossing the Sillilica Pass in May, -1907, at 15,750 feet (4,800 m.). Perpetual snow lay at an estimated -height of 2,000-2,500 feet above the pass or 18,000 feet (5,490 m.) -above the sea. Two weeks later the Huasco Basin, 14,050 feet (4,280 m.), -was covered a half-foot deep with snow and a continuous snow mantle -extended down to 13,000 feet. Light snows are reported from 12,000 feet, -but they remain a few hours only and are restricted to the height of -exceptionally severe winter seasons (June and early July). Three or four -distant snow-capped peaks were observed and estimates made of the -elevation of the snowline between the Cordillera Sillilica and Llica on -the eastern border of the Maritime Cordillera. All observations agreed -in giving an elevation much in excess of 17,000 feet. In general the -values run from 18,000 to 19,000 feet (5,490 to 5,790 m.). Though the -bases of these figures are estimates, it should be noted that a large -part of the trail lies between 14,000 and 16,000 feet, passing mountains -snow-free at least 2,000 to 3,000 feet higher, and that for general -comparisons they have a distinct value. - -In the Eastern Cordillera of Bolivia, snow was observed on the summit of -the Tunari group of peaks northwest of Cochabamba. Steinmann, who -visited the region in 1904, but did not reach the summit of the Tunari -group of peaks, concludes that the limit of perpetual snow should be -placed above the highest point, 17,300 (5,270 m.); but in July and -August, 1907, I saw a rather extensive snow cover over at least the -upper 1,000 feet, and what appeared to be a very small glacier. Certain -it is that the Cochabamba Indians bring clear blue ice from the Tunari -to the principal hotels, just as ice is brought to Cliza from the peaks -above Arani. On these grounds I am inclined to place the snowline at -17,000 feet (5,180 m.) near the eastern border of the Eastern -Cordillera, latitude 17° S. At 13,000 feet, in July, 1907, snow occurred -in patches only on the pass called Abre de Malaga, northeast of Colomi, -13,000 feet, and fell thickly while we were descending the northern -slopes toward Corral, so that in the early morning it extended to the -cold timber line at 10,000 feet. In a few hours, however, it had -vanished from all but the higher and the shadier situations. - -In the Vilcanota knot above the divide between the Titicaca and -Vilcanota hydrographic systems, the elevation of the snowline was -16,300+ feet (4,970 m.) in September, 1907. On the Cordillera Real of -Bolivia it is 17,000 to 17,500 feet on the northeast, but falls to -16,000 feet on the southwest above La Paz. In the first week of July, -1911, snow fell on the streets of Cuzco (11,000 feet) and remained for -over an hour. The heights north of San Geronimo (16,000 feet) miss the -limit of perpetual snow and are snow-covered only a few months each -year. - -In taking observations on the snowline along the seventy-third meridian -I was fortunate enough to have a topographer the heights of whose -stations enabled me to correct the readings of my aneroid barometer -whenever these were taken off the line of traverse. Furthermore, the -greater height of the passes--15,000 to 17,600 feet--brought me more -frequently above the snowline than had been the case in Bolivia and -Chile. More detailed observations were made, therefore, not only upon -the elevation of the snowline from range to range, but also upon the -degree of canting of the snowline on a given range. Studies were also -made on the effect of the outline of the valleys upon the extent of the -glaciers, the influence on the position of the snowline of mass -elevation, precipitation, and cloudiness. - -Snow first appears at 14,500 feet (4,320 m.) on the eastern flanks of -the Cordillera Vilcapampa, in 13° south latitude. East of this group of -ridges and peaks as far as the extreme eastern border of the mountain -belt, fifty miles distant, the elevations decrease rapidly to 10,000 -feet and lower, with snow remaining on exceptionally high peaks from a -few hours to a few months. In the winter season snow falls now and then -as low as 11,500 feet, as in the valley below Vilcabamba pueblo in early -September, 1911, though it vanishes like mist with the appearance of the -sun or the warm up-valley winds from the forest. Storms gather daily -about the mountain summits and replenish the perpetual snow above 15,000 -feet. In the first pass above Puquiura we encountered heavy snow banks -on the northeastern side a hundred feet below the pass (14,500 feet), -but on the southwestern or leeward side it is five hundred feet lower. -This distribution is explained by the lesser insolation on the -southwestern side, the immediate drifting of the clouds from the -windward to the leeward slopes, and to the mutual intensification of -cause and effect by topographic changes such as the extension of -collecting basins and the steeping of the slopes overlooking them with a -corresponding increase in the duration of shade. - -It is well known that with increase of elevation and therefore of the -rarity of the air there is less absorption of the sun's radiant energy, -and a corresponding increase in the degree of insolation. It follows, -therefore, that at high altitudes the contrasts between sun and shade -temperatures will increase. Frankland[56] has shown that the increase -may run as high as 500 per cent between 100 to 10,000 feet above the -sea. I have noted a fall of temperature of 15° F. in six minutes, due to -the obscuring of the sun by cloud at an elevation of 16,000 feet above -Huichihua in the Central Ranges of Peru. Since the sun shines -approximately half the time in the snow-covered portions of the -mountains and since the tropical Andes are of necessity snow-covered -only at lofty elevations, this contrast between shade and sun -temperatures is by far the most powerful factor influencing differences -in elevation of the snowline in Peru. - -To the drifting of the fallen snow is commonly ascribed a large portion -of this contrast. I have yet to see any evidence of its action near the -snowline, though I have often observed it, especially under a high wind -in the early morning hours at considerable elevations above the -snowline, as at the summits of lofty peaks. It appears that the lower -ranges bearing but a limited amount of snow are not subject to drifting -because of the wetness of the snow, and the fact that it is compacted by -occasional rains and hail storms. Only the drier snow at higher -elevations and under stronger winds can be effectively dislodged. - -The effect of unequal distribution of precipitation on the windward and -leeward slopes of a mountain range is in general to depress the snowline -on the windward slopes where the greater amount falls, but this may be -offset in high altitudes by temperature contrasts as in the westward -trending Cordillera Vilcapampa, where north and south slopes are in -opposition. If the Cordillera Vilcapampa ran north and south we should -have the windward and leeward slopes equally exposed to the sun and the -snowline would lie at a lower elevation on the eastern side. Among all -the ranges the slopes have decreasing precipitation to the leeward, that -is, westerly. The second and third passes, between Arma and Choquetira, -are snow-free (though their elevations equal those of the first pass) -because they are to leeward of the border range, hence receive less -precipitation. The depressive effect of increased precipitation on the -snowline is represented by A-B, Fig. 184; in an individual range the -effect of heavier precipitation may be offset by temperature contrasts -between shady and sunny slopes, as shown by the line a-b in the same -figure. - -The degree of canting of the snowline on opposite slopes of the -Cordillera Vilcapampa varies between 5° and 12°, the higher value being -represented four hours southwest of Arma on the Choquetira trail, -looking northeast. A general view of the Cordillera looking east at this -point (Fig. 186), shows the appearance of the snowline as one looks -along the flanks of the range. In detail the snowline is further -complicated by topography and varying insolation, each spur having a -snow-clad and snow-free aspect as shown in the last figure. The degree -of difference on these minor slopes may even exceed the difference -between opposite aspects of the range in which they occur. - -[Illustration: FIG. 184--To illustrate the canting of the snowline. -_A-B_ is the snowline depressed toward the north (right) in response to -heavier precipitation. The line _a-b_ represents a depression in the -opposite direction due to the different degree of insolation on the -northern (sunny) and southern (shady) slopes.] - -To these diversifying influences must be added the effect of warm -up-valley winds that precede the regular afternoon snow squalls and that -melt the latest fall of snow to exceptionally high elevations on both -the valley floor and the spurs against which they impinge. The influence -of the warmer air current is notably confined to the heads of those -master valleys that run down the wind, as in the valley heading at the -first pass, Cordillera Vilcapampa, and at the heads of the many valleys -terminating at the passes of the Maritime Cordillera. Elsewhere the -winds are dissipated in complex systems of minor valleys and their -effect is too well distributed to be recognized. - -It is clear from the conditions of the problem as outlined on preceding -pages that the amount of canting may be expressed in feet of difference -of the snowline on opposite sides of a range or in degrees. The former -method has, heretofore, been employed. It is proposed that this method -should be abolished and degrees substituted, on the following grounds: -Let _A_ and _B_, Fig. 190, represent two mountain masses of unequal area -and unequal elevation. Let the opposite ends of the snowlines of both -figures lie 1,000 feet apart as between the windward and leeward sides -of a broad cordillera (A), or as between the relatively sunnier and -relatively shadier slopes of individual mountains or narrow ranges in -high latitudes or high altitudes (B). With increasing elevation there is -increasing contrast between temperatures in sunshine and in shade, hence -a greater degree of canting (B). Tending toward a still greater degree -of contrast is the effect of the differences in the amounts of snowy -precipitation, which are always more marked on an isolated and lofty -mountain summit than upon a broad mountain mass (1) because in the -former there is a very restricted area where snow may accumulate, and -(2) because with increase of elevation there is a rapid and differential -decrease in both the rate of adiabatic cooling and the amount of water -vapor; hence the snow-producing forces are more quickly dissipated. - -[Illustration: FIG. 185--Glacial features in the Peruvian Andes near -Arequipa. Sketched from a railway train, July, 1911. The horizontal -broken lines represent the lower limit of light snow during late June, -1911. There is a fine succession of moraines in U-shaped valleys in all -the mountains of the Arequipa region. _A_ represents a part of Chacchani -northwest of Arequipa; _B_ is looking south by east at the northwest end -of Chacchani near Pampa de Arrieros; _C_ also shows the northwest end of -Chacchani from a more distant point.] - -[Illustration: FIG. 186--Canted snowline in the Cordillera Vilcapampa -between Arma and Choquetira. Looking east from 13,500 feet.] - -[Illustration: FIG. 187--Glacial topography between Lambrama and -Antabamba in the Central Ranges. A recent fall of snow covers the -foreground. The glaciers are now almost extinct and their action is -confined to the deepening and steepening of the cirques at the valley -heads.] - -[Illustration: FIG. 188--Asymmetrical peaks in the Central Ranges -between Antabamba and Lambrama. The snow-filled hollows in the -photograph face away from the sun--that is, south--and have retained -snow since the glacial epoch; while the northern slopes are snow-free. -There is no true glacial ice and the continued cirque recession is due -to nivation.] - -[Illustration: FIG. 189--Glacial topography north of the divide on the -seventy-third meridian. Maritime Cordillera. Looking downstream at an -elevation of 16,500 feet (5,030 m.).] - -Furthermore, the leeward side of a lofty mountain not only receives much -less snow proportionally than the leeward side of a lower mountain, -but also loses it faster on account of the smaller extent of surface -upon which it is disposed and the proportionally larger extent of -counteractive, snow-free surface about it. Among the volcanoes of -Ecuador are many that show differences of 500 feet in snowline elevation -on windward and leeward (east) slopes and some, as for example -Chimborazo, that exhibit differences of 1,000 feet. The latter figure -also expresses the differences in the broad Cordillera Vilcapampa and in -the Maritime Cordillera, though the _rate_ of canting as expressed in -degrees is much greater in the case of the western mountains. - -[Illustration: FIG. 190--To illustrate the difference in the degree of -canting of the snowline on large and on small mountain masses.] - -The advantages of the proposed method of indicating the degree of -canting of the snowline lie in the possibility thus afforded of -ultimately separating and expressing quantitatively the various factors -that affect the position of the line. In the Cordillera Vilcapampa, for -example, the dominant canting force is the difference between sun and -shade temperatures, while in the volcanoes of Ecuador, where -_symmetrical volcanoes, almost on the equator, have equal insolation on -all aspects_ and the temperature contrasts are reduced to a minimum--the -differences are owing chiefly to varying exposure to the winds. The -elusive factors in the comparison are related to the differences in area -and in elevation. - -The value of arriving finally at close snowline analyses grows out of -(1) the possibility of snowline changes in short cycles and (2) -uncertainty of arriving by existing methods at the snowline of the -glacial period, whose importance is fundamental in refined physiographic -studies in glaciated regions with a complex topography. To show the -application of the latter point we shall now attempt to determine the -snowline of the glacial period in the belt of country along the route of -the Expedition. - -In the group of peaks shown in Fig. 188 between Lambrama and Antabamba, -the elevation of the snowline varies from 16,000 to 17,000 feet -(4,880-5,180 m.), depending on the topography and the exposure. The -determination of the limit of perpetual snow was here, as elsewhere -along the seventy-third meridian, based upon evidences of nivation. It -will be observed in Fig. 191 that just under the snow banks to the left -of the center are streams of rock waste which head in the snow. Their -size is roughly proportional to the size of the snow banks, and, -furthermore, they are not found on snow-free slopes. From these facts it -is concluded that they represent the waste products of snow erosion or -nivation, just as the hollows in which the snow lies represent the -topographic products of nivation. On account of the seasonal and annual -variation in precipitation and temperature--hence in the elevation of -the snowline--it is often difficult to make a correct snowline -observation based upon depth and _apparent_ permanence. Different -observers report great changes in the snowline in short intervals, -changes not explained by instrumental variations, since they are -referred to topographic features. It appears to be impossible to rely -upon present records for small changes possibly related to minor -climatic cycles because of a lack of standardization of observations. - -Nothing in the world seems simpler at first sight than an observation on -the elevation of the snowline. Yet it can be demonstrated that large -numbers of observers have merely noted the position of temporary snow. -It is strongly urged that evidences of nivation serve henceforth as -proof of permanent snow and that photographic records be kept for -comparison. In this way measurements of changes in the level of the -snowline may be accurately made and the snow cover used as a climatic -gauge. - -Farther west in the Maritime Cordillera, the snowline rises to 18,000 -feet on the northern slopes of the mountains and to 17,000 feet on the -southern slopes. The top of the pass above Cotahuasi, 17,600 feet (5,360 -m.), was snow-free in October, 1911, but the snow extended 500 feet -lower on the southern slope. The degree of canting is extraordinary at -this point, single volcanoes only 1,500 to 2,000 feet above the general -level and with bases but a few miles in circumference exhibit a thousand -feet of difference in the snowline upon northern and southern aspects. -This is to be attributed no less to the extreme elevation of the snow -(and, therefore, stronger contrasts of shade and sun temperatures) than -to the extreme aridity of the region and the high daytime temperatures. -The aridity is a factor, since heavy snowfall means a lengthening of the -period of precipitation in which a cloud cover shuts out the sun and a -shortening of the period of insolation and melting. - -Contrasts between shade and sun temperatures increase with altitude but -their effects also increase in _time_. Of two volcanoes of equal size -and both 20,000 feet above sea level, that one will show the greater -degree of canting that is longer exposed to the sun. The high daytime -temperature is a factor, since it tends to remove the thinnest snow, -which also falls in this case on the side receiving the greatest amount -of heat from the sun. The high daytime temperature is phenomenal in this -region, and is owing to the great extent of snow-free land at high -elevations and yet below the snowline, and to the general absence of -clouds and the thinness of vegetation. - -On approach to the western coast the snowline descends again to 17,500 -feet on Coropuna. There are three chief reasons for this condition. -First, the well-watered Majes Valley is deeply incised almost to the -foot of Coropuna, above Chuquibamba, and gives the daily strong sea -breeze easy access to the mountain. Second, the Coast Range is not only -low at the mouth of the Majes Valley, but also is cut squarely across by -the valley itself, so that heavy fogs and cloud sweep inland nightly and -at times completely cover both valley and desert for an hour after -sunrise. Although these yield no moisture to the desert or the valley -floor except such as is mechanically collected, yet they do increase the -precipitation upon the higher elevations at the valley head. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM DIRECTOR - -ANTABAMBA QUADRANGLE] - -A third factor is the size of Coropuna itself. The mountain is not a -simple volcano but a composite cone with five main summits reaching well -above the snowline, the highest to an elevation of 21,703 feet (6,615 -m.). It measures about 20 miles (32 km.) in circumference at the -snowline and 45 miles (72 km.) at its base (measuring at the foot of the -steeper portion), and stands upon a great tributary lava plateau from -15,000 to 17,000 feet above sea level. Compared with El Misti, at -Arequipa, its volume is three times as great, its height two thousand -feet more, and its access to ocean winds at least thirty per cent more -favorable. El Misti, 19,200 feet (5,855 m.) has snow down as far as -16,000 feet in the wet season and rarely to 14,000 feet, though by -sunset a fall of snow may almost disappear whose lower limit at sunrise -was 16,000 feet. Snow may accumulate several thousand feet below the -summit during the wet season, and in such quantities as to require -almost the whole of the ensuing dry season (March to December) for its -melting. Northward of El Misti is the massive and extended range, -Chachani, 20,000 feet (6,100 m.) high; on the opposite side is the -shorter range called Pichu-Pichu. Snow lies throughout the year on both -these ranges, but in exceptional seasons it nearly disappears from -Chachani and wholly disappears from Pichu-Pichu, so that the snowline -then rises to 20,000 feet. It is considered that the mean of a series of -years would give a value between 17,000 and 18,000 feet for the snowline -on all the great mountains of the Arequipa region.[57] This would, -however, include what is known to be temporary snow; the limit of -"perpetual" snow, or the true snowline, appears to lie about 19,000 feet -on Chachani and _above_ El Misti, say 19,500 feet. It is also above the -crest of Pichu-Pichu. The snowline, therefore, appears to rise a -thousand feet from Coropuna to El Misti, owing chiefly to the poorer -exposure of the latter to the sources of snowy precipitation. - -It may also be noted that the effect of the easy access of the ocean -winds in the Coropuna region is also seen in the increasing amount of -vegetation which appears in the most favorable situations. Thus, along -the Salamanca trail only a few miles from the base of Coropuna are a few -square kilometers of _quenigo_ woodland generally found in the cloud -belt at high altitudes; for example, at 14,000 feet above Lambrama and -at 9,000 feet on the slope below Incahuasi, east of Pasaje. The greater -part of the growth is disposed over hill slopes and on low ridges and -valley walls. It is, therefore, clearly unrelated as a whole to the -greater amount of ground-water with which a part is associated, as along -the valley floors of the streams that head in the belt of perpetual -snow. The appearance of this growth is striking after days of travel -over the barren, clinkery lava plateau to eastward that has a less -favorable exposure. The _quenigo_ forest, so-called, is of the greatest -economic value in a land so desolate as the vast arid and semi-arid -mountain of western Peru. Every passing traveler lays in a stock of -fire-wood as he rests his beasts at noonday; and long journeys are made -to these curious woodlands from both Salamanca and Chuquibamba to gather -fuel for the people of the towns. - - -NIVATION - -The process of nivation, or snow erosion, does not always produce -visible effects. It may be so feeble as to make no impression upon very -resistant rock where the snow-fall is light and the declivity low. -Ablation may in such a case account for almost the whole of the snow -removed. On strong and topographically varied slopes where the snow is -concentrated in headwater alcoves, there is a more pronounced downward -movement of the snow masses with more prominent effects both of erosion -beneath the snow and of accumulation at the border of the snow. In such -cases the limit of perpetual snow may be almost as definitely known as -the limit of a glacier. Like glaciers these more powerful snow masses -change their limits in response to regional changes in precipitation, -temperature, or both. It would at first sight appear impossible to -distinguish between these changes through the results of nivation. Yet -in at least a few cases it may be as readily determined as the past -limits of glaciers are inferred from the terminal moraines, still -intact, that cross the valley floors far below the present limits of the -ice. - -In discussing the process of nivation it is necessary to assume a -sliding movement on the part of the snow, though it is a condition in -Matthes' original problem in which the nivation idea was introduced that -the snow masses remain stationary. It is believed, however, that -Matthes' valuable observations and conclusions really involve but half -the problem of nivation; or at the most but one of two phases of it. He -has adequately shown the manner in which that phase of nivation is -expressed which we find _at the border of the snow_. Of the action -_beneath_ the snow he says merely: "Owing to the frequent oscillations -of the edge and the successive exposure of the different parts of the -site to frost action, the area thus affected will have no well-defined -boundaries. The more accentuated slopes will pass insensibly into the -flatter ones, and the general tendency will be to give the drift site a -cross section of smoothly curved outline and ordinarily concave."[58] - -From observations on the effects of nivation in valleys, Matthes further -concludes that "on a grade of about 12 per cent ... névé must attain a -thickness of at least 125 feet in order that it may have motion,"[59] -though as a result of the different line of observations Hobbs -concludes[60] that a somewhat greater thickness is required. - -[Illustration: FIG. 191--The "pocked" surface characteristically -developed in the zone of light nivation. Compare with Fig. 194, showing -the effects of heavy nivation.] - -[Illustration: FIG. 192--Steep cirque walls and valleys head in the -Central Ranges between Lambrama and Chuquibambilla. The snow is here a -vigorous agent in transporting talus material and soil from all the -upper slopes down to the foot of the cirque wall.] - -The snow cover in tropical mountains offers a number of solid advantages -in this connection. Its limits, especially on the Cordillera Vilcapampa, -on the eastern border of the Andes, are subject to _small seasonal -oscillations_ and the edge of the "perpetual" snow is easily determined. -Furthermore, it is known from the comparatively "fixed quality of -tropical climate," as Humboldt put it, that the variations of the -snowline in a period of years do not exceed rather narrow limits. In -mid-latitudes on the contrary there is an extraordinary shifting of the -margin of the snow cover, and a correspondingly wide distribution of -the feeble effects of nivation. - -[Illustration: FIG. 193--Panta Mountain and its glacier system. The -talus-covered mass in the center (B) is a terminal moraine topped by the -dirt-stained glacier that descends from the crest. The separate glaciers -were formerly united to form a huge ice tongue that truncated the -lateral spurs and flattened the valley floor. One of its former stages -is shown by the terminal moraine in the middle distance, breached by a -stream, and impounding a lake not visible from this point of view.] - -[Illustration: FIG. 194--Recessed southern slopes of volcanoes whose -northern slopes are practically without glacial modifications. Summit of -the lava plateau, Maritime Cordillera, western Peru, between Antabamba -and Cotahuasi.] - -Test cases are presented in Figs. 191, 192, and 193, Cordillera -Vilcapampa, for the determination of the fact of the movement of the -snow long before it has reached the thickness Matthes or Hobbs believes -necessary for a movement of translation to begin. Fig. 191 shows snow -masses occupying pockets on the slope of a ridge that was never covered -with ice. Past glacial action with its complicating effects is, -therefore, excluded and we have to deal with snow action pure and -simple. The pre-glacial surface with smoothly contoured slopes is -recessed in a noteworthy way from the ridge crest to the snowline of the -glacial period at least a thousand feet lower. The recesses of the -figure are peculiar in that not even the largest of them involve the -entire surface from top to bottom; they are of small size and are -scattered over the entire slope. This is believed to be due to the fact -that they represent the limits of variations of the snowline in short -cycles. Below them as far as the snowline of the glacial period are -larger recesses, some of which are terminated by masses of waste as -extensive as the neighboring moraines, but disposed in irregular -scallops along the borders of the ridges or mountain slopes in which the -recesses have been found. - -The material accumulated at the lower limit of the snow cover of the -glacial period was derived from two sources: (1) from slopes and cliffs -overlooking the snow, (2) from beneath the snow by a process akin to ice -plucking and abrasion. The first process is well known and resembles the -shedding of waste upon a valley glacier or a névé field from the -bordering cliffs and slopes. Material derived in this manner in many -places rolls down a long incline of snow and comes to rest at the foot -of it as a fringe of talus. The snow is in this case but a substitute -for a normal mass of talus. The second process produces its most clearly -recognizable effects on slopes exceeding a declivity of 20°; and upon -30° and 40° slopes its action is as well-defined as true glacial action -which it imitates. It appears to operate in its simplest form as if -independent of the mass of the snow, small and large snow patches -showing essentially the same results. This is the reverse of Matthes' -conclusion, since he says that though the minimum thickness "must vary -inversely with the percentage of the grade," "the influence of the grade -is inconsiderable," and that the law of variation must depend upon -additional observation.[61] - -Let us examine a number of details and the argument based upon them and -see if it is not possible to frame a satisfactory law of variation. - -In Fig. 193 the chief conditions of the problem are set forth. Forward -from the right-hand peak are snow masses descending to the head of a -talus (_A_) whose outlines are clearly defined by freshly fallen snow. -At (_B_) is a glacier whose tributaries descend the middle and left -slopes of the picture after making a descent from slopes several -thousand feet higher and not visible in this view. The line beneath the -glacier marks the top of the moraine it has built up. Moraines farther -down valley show a former greater extent of the glacier. Clearly the -talus material at (_A_) was accumulated after the ice had retreated to -its present position. It will be readily seen from an inspection of the -photograph that the total amount of material at (_A_) is an appreciable -fraction of that in the moraine. The ratio appears to be about 1:8 or -1:10. I have estimated that the total area of snow-free surface about -the snowfields of the one is to that of the other as 2:3. The gradients -are roughly equivalent, but the volume of snow in the one case is but a -small fraction of that in the other. It will be seen that the snow -masses have recessed the mountain slopes at _A_ and formed deep hollows -and that the hollowing action appears to be most effective where the -snow is thickest. - -Summarizing, we note first, that the roughly equivalent factors are -gradient and amount of snow-free surface; second, that the unequal -factors are (a) accumulated waste, (b) degree of recessing, and (c) the -degree of compacting of snow into ice and a corresponding difference in -the character of the glacial agent, and (d) the extent of the snow -cover. The direct and important relation of the first two unequal -factors to the third scarcely need be pointed out. - -We have then an inequality in amount of accumulated material to be -explained by either an inequality in the extent of the snow and -therefore an inequality of snow action, or an inequality due to the -presence of ice in one valley and not in the other, or by both. It is at -once clear that if ice is absent above (_A_) and the mountain slopes are -recessed that snow action is responsible for it. It is also recognized -that whatever rate of denudation be assigned to the snow-free surfaces -this rate must be exceeded by the rate of snow action, else the -inequalities of slope would be decreased rather than increased. The -accumulated material at (_A_) is, therefore, partly but not chiefly due -to denudation of snow-free surfaces. It is due chiefly to _erosion_ -beneath the snow. Nor can it be argued that the hollows now occupied by -snow were formed at some past time when ice not snow lay in them. They -are not ice-made hollows for they are on a steep spur above the limits -of ice action even in the glacial period. Any past action is, therefore, -represented here in _kind_ by present action, though there would be -differences in _degree_ because the heavier snows of the past were -displaced by the lighter snows of today. - -While it appears that the case presents clear proof of degradation by -snow it is not so clear how these results were accomplished. Real -abrasion on a large scale as in bowlder-shod glaciers is ruled out, -since glacial striæ are wholly absent from nivated surfaces according to -both Matthes' observations and my own. Yet all nivated surfaces have -very distinctive qualities, delicately organized slopes which show a -marked change from any original condition related to water-carving. In -the absence of striæ, the general absence of all but a thin coating of -waste _even in rock hollows_, and the accumulation of waste up to -bowlders in size at the lower edge of the nivated zone, I conclude that -compacted snow or névé of sufficient thickness and gradient may actually -pluck rock outcrops in the same manner though not at the rate which ice -exhibits. That the products of nivation may be bowlders as well as fine -mud would seem clearly to follow increase in effectiveness, due to -increase in amount of the accumulated snow; that bowlders are actually -transported by snow is also shown by their presence on the lower margins -of nivated tracts. - -Our argument may be made clearer by reference to the observed action of -snow in a particular valley. Snow is shed from the higher, steeper -slopes to the lower slopes and eventually accumulates to a marked degree -on the bottoms of the depressions, whence it is avalanched down valley -over a series of irregular steps on the valley floor. An avalanche takes -place through the breaking of a section of snow just as an iceberg -breaks off the end of a tide-water glacier. Evidently there must be -pressure from behind which crowds the snow forward and precipitates it -to a lower level. - -As a snow mass falls it not only becomes more consolidated, beginning at -the plane of impact, but also gives a shock to the mass upon which it -falls that either starts it in motion or accelerates its rate of motion. -The action must therefore be accompanied by a drag upon the floor and if -the rock be close-jointed and the blocks, defined by the joint planes, -small enough, they will be transported. Since snow is not so compact as -ice and permits included blocks easily to adjust themselves to new -resistances, we should expect the detached blocks included in the snow -to change their position constantly and to form irregular scratches, but -not parallel striæ of the sort confidently attributed to stone-shod ice. - -It is to the plasticity of snow that we may look for an explanation of -the smooth-contoured appearance of the landscape in the foreground of -Fig. 135. The smoothly curved lines are best developed where the entire -surface was covered with snow, as in mid-elevations in the larger -snowfields. At higher elevations, where the relief is sharper, the snow -is shed from the steeper declivities and collected in the minor basins -and valley heads, where its action tends to smooth a floor of limited -area, while snow-free surfaces retain all their original irregularities -of form or are actually sharpened. - -The degree of effectiveness of snow and névé action may be estimated -from the reversed slopes now marked by ponds or small marshy tracts -scattered throughout the former névé fields, and the many niched -hollows. They are developed above Pampaconas in an admirable manner, -though their most perfect and general development is in the summit belt -of the Cordillera Vilcapampa between Arma and Choquetira, Fig. 135. It -is notable in _all_ cases where nivation was associated with the work of -valley glaciers that the rounded nivated slopes break rather sharply -with the steep slopes that define an inner valley, whose form takes on -the flat floor and under-cut marginal walls normal to valley glaciation. - -A classification of numerous observations in the Cordillera Vilcapampa -and in the Maritime Cordillera between Lambrama and Antabamba may now be -presented as the basis for a tentative expression of the law of -variation respecting snow motion. The statement of the law should be -prefaced by the remark that thorough checking is required under a wider -range of conditions before we accept the law as final. Near the lower -border of the snow where rain and hail and alternate freezing and -thawing take place, the snow is compacted even though but fifteen to -twenty feet thick, and appears to have a down-grade movement and to -exercise a slight drag upon its floor when the gradient does not fall -below 20°. Distinct evidences of nivation were observed on slopes with a -declivity of 5° near summit areas of past glacial action, where the snow -did not have an opportunity to be alternately frozen and thawed. - -The _thickness_ of the former snow cover could, however, not be -accurately determined, but was estimated from the topographic -surroundings to have been at least several hundred feet. Upon a 40° -slope a snow mass 50 feet thick was observed to be breaking off at a -cliff-face along the entire cross-section as if impelled forward by -thrust, and to be carrying a small amount of waste--enough distinctly to -discolor the lowermost layers--which was shed upon the snowy masses -below. With increase in the degree of compactness of the snow at -successively lower elevations along a line of snow discharge, gradients -down to 25° were still observed to carry strongly crevassed, waste-laden -snow down to the melting border. It appeared from the clear evidences of -vigorous action--the accumulation of waste, the strong crevassing, the -stream-like character of the discharging snow, and the pronounced -topographic depression in which it lay--that much flatter gradients -would serve, possibly not more than 15°, for a snow mass 150 feet wide, -30 to 40 feet thick, and serving as the outlet for a set of tributary -slopes about a square mile in area and with declivities ranging from -small precipices to slopes of 30°. - -We may say, therefore, that the factors affecting the rate of motion are -(1) thickness, (2) degree of compactness, (3) diurnal temperature -changes, and (4) gradient. Among these, diurnal temperature changes -operate indirectly by making the snow more compact and also by inducing -motion directly. At higher elevations above the snowline, temperature -changes play a decreasingly important part. The thickness required -varies inversely as the gradient, and upon a 20° slope is 20 feet for -wet and compact snow subjected to alternate freezing and thawing. For -dry snow masses above the zone of effective diurnal temperature changes, -an increasing gradient is required. With a gradient of 40°, less than 50 -feet of snow will move _en masse_ if moderately compacted under its own -weight; if further compacted by impact of falling masses from above, the -required thickness may diminish to 40 feet and the required declivity to -15°. The gradient may decrease to 0° or actually be reversed and motion -still continue provided the compacting snow approach true névé or even -glacier ice as a limit. - -From the sharp topographic break between the truly glaciated portions of -the valley in regions subjected to temporary glaciation, it is concluded -that the eroding power of the moving mass is suddenly increased at the -point where névé is finally transformed into true ice. This -transformation must be assumed to take place suddenly to account for so -sudden a change of function as the topographic break requires. Below the -point at which the transformation occurs the motion takes place under a -new set of conditions whose laws have already been formulated by -students of glaciology. - -[Illustration: FIG. 195--Curve of snow motion. Based on many -observations of snow motion to show minimum thickness of snow required -to move on a given gradient. Figures on the left represent thickness of -snow in feet. The degrees represent the gradient of the surface. The -gradients have been run in sequence down to 0° for the sake of -completing the accompanying discussion. Obviously no glacially -unmodified valley in a region of mountainous relief would start with so -low a gradient, though glacial action would soon bring it into -existence. Between +5° and -5° the curve is based on the gradients of -nivated surfaces.] - -The foregoing readings of gradient and depth of snow are typical of a -large number which were made in the Peruvian Andes and which have served -as the basis of Fig. 195. It will be observed that between 15° and 20° -there is a marked change of function and again between +5° and -5° -declivity, giving a double reversed curve. The meaning of the change -between 15° and 20° is inferred to be that, with gradients over 20°, -snow cannot wholly resist gravity in the presence of diurnal temperature -changes across the freezing point and occasional snow or hail storms. -With increase of thickness compacting appears to progress so rapidly as -to permit the transfer of thrust for short distances before absorption -of thrust takes place in the displaced snow. At 250 feet thorough -compacting appears to take place, enabling the snow to move out under -its own weight on even the faintest slopes; while, with a thickness -still greater, the resulting névé may actually be forced up slight -inclines whose declivity appears to approach 5° as a limit. I have -nowhere been able to find in truly nivated areas reversed curves -exceeding 5°, though it should be added that depressions whose leeward -slopes were reversed to 2° and 3° are fairly common. If the curve were -continued we should undoubtedly find it again turning to the left at the -point where the thickness of the snow results in the transformation of -snow to ice. From the sharp topographic break observed to occur in a -narrow belt between the névé and the ice, it is inferred that the -erosive power of the névé is to that of the ice as 2:4 or 1:5 _for equal -areas_; and that reversed slopes of a declivity of 10° to 15° may be -formed by glaciers is well known. Precisely what thickness of snow or -névé is necessary and what physical conditions effect its transformation -into ice are problems not included in the main theme of this chapter. - -It is important that the proposed curve of snow motion under minimum -conditions be tested under a large variety of circumstances. It may -possibly be found that each climatic region requires its special -modifications. In tropical mountains the sudden alternations of freezing -and thawing may effect such a high degree of compactness in the snow -that lower minimum gradients are required than in the case of -mid-latitude mountains where the perpetual snow of the high and cold -situations is compacted through its own weight. Observations of the -character introduced here are still unattainable, however. It is hoped -that they will rapidly increase as their significance becomes apparent; -and that they have high significance the striking nature of the curve of -motion seems clearly to establish. - - -BERGSCHRUNDS AND CIRQUES - -The facts brought out by the curve of snow-motion (Fig. 195) have an -immediate bearing on the development of cirques, whose precise mode of -origin and development have long been in doubt. Without reviewing the -arguments upon which the various hypotheses rest, we shall begin at once -with the strongest explanation--W. D. Johnson's famous bergschrund -hypothesis. The critical condition of this hypothesis is the diurnal -migration across the freezing point of the air temperature at the bottom -of the schrund. Alternate freezing and thawing of the water in the -joints of the rock to which the schrund leads, exercise a quarrying -effect upon the rock and, since this effect is assumed to take place at -the foot of the cirque, the result is a steady retreat of the steep -cirque wall through basal sapping. - -While Johnson's hypothesis has gained wide acceptance and is by many -regarded as the final solution of the cirque problem it has several -weaknesses in its present form. In fact, I believe it is but one of two -factors of equal importance. In the first place, as A. C. Andrews[62] -has pointed out, it is extremely improbable that the bergschrund of -glacial times under the conditions of a greater volume of snow could -have penetrated to bedrock at the base of the cirque where the present -change of slope takes place. In the second place, the assumption is -untenable that the bergschrund in all cases reaches to or anywhere near -the foot of the cirque wall. A third condition outside the hypothesis -and contradictory to it is the absence of a bergschrund in snowfields at -many valleys heads where cirques are well developed! - -Johnson himself called attention to the slender basis of observation -upon which his conclusions rest. In spite of his own caution with -respect to the use of his meager data, his hypothesis has been applied -in an entirely too confident manner to all kinds of cirques under all -kinds of conditions. Though Johnson descended an open bergschrund to a -rock floor upon which ice rested, his observations raise a number of -proper questions as to the application of these valuable data: How long -are bergschrunds open? How often are they open? Do they everywhere open -to the foot of the cirque wall? Are they present for even a part of the -year in all well-developed cirques? Let us suppose that it is possible -to find many cirques filled with snow, not ice, surrounded by truly -precipitous walls and with an absence of bergschrunds, how shall we -explain the topographic depressions excavated underneath the snow? If -cirque formation can be shown to take place without concentrated frost -action at the foot of the bergschrund, then is the bergschrund not a -secondary rather than a primary factor? And must we not further conclude -that when present it but hastens an action which is common to all -snow-covered recesses? - -It is a pleasure to say that we may soon have a restatement of the -cirque problem from the father of the bergschrund idea. The argument in -this chapter was presented orally to him after he had remarked that he -was glad to know that some one was finding fault with his hypothesis. -"For," he said, with admirable spirit, "I am about to make a most -violent attack upon the so-called Johnson hypothesis." I wish to say -frankly that while he regards the following argument as a valid addition -to the problem, he does not think that it solves the problem. There are -many of us who will read his new explanation with the deepest interest. - -[Illustration: FIG. 196--Relation of cirque wall to trough's end at the -head of a glaciated valley. The ratio of the inner to the outer radius -is 1:4.] - -[Illustration: FIG. 197--Mode of cirque formation. Taking the facts of -snow depth represented in the curve, Fig. 195, and transposing them over -a profile (the heavy line) which ranges from 0° declivity to 50°, we -find that the greatest excess of snow occurs roughly in the center. Here -ice will first form at the bottom of the snow in the advancing hemicycle -of glaciation, and here it will linger longest in the hemicycle of -retreat. Here also there will be the greatest mass of névé. All of these -factors are self-stimulating and will increase in time until the floor -of the cirque is flattened or depressed sufficiently to offset through -uphill ice-flow the augmented forces of erosion. The effects of -self-stimulation are shown by "snow increase"; the ice shoe at the -bottom of the cirque is expressed by "ice factor." The form accompanying -both these terms is merely suggestive. The top of "excess snow" has a -gradient characteristic of the surface of snow fields. A preglacial -gradient of 0° is not permissible, but I have introduced it to complete -the discussion in the text and to illustrate the flat floor of a cirque. -A bergschrund is not required for any stage of this process, though the -process is hastened wherever bergschrunds exist.] - -We shall begin with the familiar fact that many valleys, now without -perpetual snow, formerly contained glaciers from 500 to 1,000 feet thick -and that their snowfields were of wide extent and great depth. At the -head of a given valley where the snow is crowded into a small -cross-section it is compacted and suffers a reduction in its volume. At -first nine times the volume of ice, the gradually compacting névé -approaches the volume of ice as a limit. At the foot of the cirque wall -we may fairly assume in the absence of direct observations, a volume -reduction of one-half due to compacting. But this is offset in the case -of a well-developed cirque by volume increases due to the convergence of -the snow from the surrounding slopes, as shown in Fig. 196. Taking a -typical cirque from a point above Vilcabamba pueblo I find that the -radius of the trough's end is to the radius of the upper wall of the -cirque as 1:4; and since the corresponding surfaces are to one another -as the squares of their similar dimensions we have 1:4 or 1:16 as the -ratio of their snow areas. If no compacting took place, then to -accommodate all the snow in the glacial trough would require an increase -in thickness in the ratio of 1:4. If the snow were compacted to half its -original volume then the ratio would be 1:2. Now, since the volume ratio -of ice to snow is 1:9 and the thickness of the ice down valley is, say -400 feet, the equivalent of loose snow at the foot of the cirque must be -more than 1:4 over 1:9 or more than two and one-quarter times thicker, -or 400 feet thick; and would give a pressure of (900 ÷ 10) × 62.5 -pounds, or 5,625 pounds, or a little less than three tons per square -foot. Since a pressure of 2,500 pounds per square foot will convert snow -into ice at freezing temperature, it is clear that ice and not snow was -the state at the bottom of the mass in glacial times. Further, between -the surface of the snow and the surface of the bottom layer of the ice -there must have been every gradation between loose snow and firm ice, -with the result that a thickness much less than 900 feet must be -assumed. Precisely what thickness would be found at the foot of the -cirque wall is unknown. But granting a thickness of 400 feet of ice an -additional 300 feet for névé and snow would raise the total to 700 feet. - -The application of the facts in the above paragraph is clearly seen when -we refer to Fig. 197. The curve of snow motion of Fig. 195 is applied to -an unglaciated mountain valley. Taking a normal snow surface and filling -the valley head it is seen that the excess of snow depth over the amount -required to give motion is a measure at various points in the valley -head and at different gradients of the erosive force of the snow. It is -strikingly concentrated on the 15°-20° gradient which is precisely where -the so-called process of basal sapping is most marked. If long continued -the process will lead to the developing of a typical cirque for it is a -process that is self-stimulating. The more the valley is changed in form -the more it tends to change still further in form because of deepening -snowfields until cliffed pinnacles and matterhorns result. - -By further reference to the figure it is clear that a schrund 350 feet -deep could not exist on a cirque wall with a declivity of even 20° -without being closed by flow, unless we grant _more rapid flow_ below -the crevasse. In the case of a glacier flowing over a nearly flat bed -away from the cirque it is difficult to conceive of a rate of flow -greater than that of snow and névé on the steep lower portion of the -cirque wall, when movement on that gradient _begins_ with snow but 20 -feet thick. - -In contrast to this is the view that the schrund line should lie well up -the cirque wall where the snow is comparatively thin and where there is -an approach to the lower limits of movement. The schrund would appear to -open where the bottom material changes its form, i.e., where it first -has its motion accelerated by transformation into névé. In this view -the schrund opens not at the foot of the cirque wall but well above it -as in Fig. 198, in which _C_ represents snow from top to bottom; _B_, -névé; and _A_, ice. The required conditions are then (1) that the -steepening of the cirque wall from _x_ to _y_ should be effected by -sapping originated at _y_ through the agencies outlined by Johnson; (2) -that the steepening from _x_ to _y_ should be effected by sapping -originated at _x_ through the change of the agent from névé to ice with -a sudden change of function; (3) and that the essential unity of the -wall _x-y-z_ be maintained through the erosive power of the névé, which -would tend to offset the formation of a shelf along a horizontal plane -passed through _y_. The last-named process not only appears entirely -reasonable from the conditions of gradient and depth outlined on pp. 296 -to 298, but also meets the actual field conditions in all the cases -examined in the Peruvian Andes. This brings up the second and third of -our main considerations, that the bergschrund does not always or even in -many cases reach the foot of the cirque wall, and that cirques exist in -many cases where bergschrunds are totally absent. - -It is a striking fact that frost action at the bottom of the bergschrund -has been assumed to be the only effective sapping force, in spite of the -common observation that bergschrunds lie in general well toward the -upper limits of snowfields--so far, in fact, that their bottoms in -general occur several hundred feet above the cirque floors. Is the -cirque under these circumstances a result of the schrund or is the -schrund a result of the cirque? _In what class of cirques do schrunds -develop?_ If cirque development in its early stages is not marked by the -development of bergschrunds, then are bergschrunds an _essential_ -feature of cirques in their later stages, however much the sapping -process may be hastened by schrund formation? - -Our questions are answered at once by the indisputable facts that many -schrunds occur well toward the upper limit of snow, and that many -cirques exist whose snowfields are not at all broken by schrunds. It was -with great surprise that I first noted the bergschrunds of the Central -Andes, especially after becoming familiar with Johnson's apparently -complete proof of their genetic relation to the cirques. But it was less -surprising to discover the position of the few observed--high up on the -cirque walls and always near the upper limit of the snowfields. - -A third fact from regions once glaciated but now snow-free also combined -with the two preceding facts in weakening the wholesale application of -Johnson's hypothesis. In many headwater basins the cirque whose wall at -a distance seemed a unit was really broken into two unequal portions; a -lower, much grooved and rounded portion and an upper unglaciated, -steep-walled portion. This condition was most puzzling in view of the -accepted explanation of cirque formation, and it was not until the two -first-named facts and the applications of the curves of snow motion were -noted that the meaning of the break on the cirque became clear. -Referring to Fig. 198 we see at once that the break occurs at _y_ and -means that under favorable topographic and geologic conditions sapping -at _y_ takes place faster than at _x_ and that the retreat of _y-z_ is -faster than _x-y_. It will be clear that when these conditions are -reversed or sapping at _x_ and at _y_ are equal a single wall will -result. On reference to the literature I find that Gilbert recently -noted this feature and called it the _schrundline_.[63] He believes that -it marks the base of the bergschrund _at a late stage in the excavation -of the cirque basin_. He notes further that the lower less-steep slope -is glacially scoured and that it forms "a sort of shoulder or terrace." - -[Illustration: FIG. 198--The development of cirques. See text, p. 209, -and Fig. 199.] - -If all the structural and topographic conditions were known in a great -variety of gathering basins we should undoubtedly find in them, and not -in special forms of ice erosion, an explanation of the various forms -assumed by cirques. The limitations inherent in a high-altitude field -and a limited snow cover prevented me from solving the problem, but it -offered sufficient evidence at least to indicate the probable lines of -approach to a solution. For example it is noteworthy that in _all_ the -cases examined the schrundline was better developed the further glacial -erosion had advanced. So constantly did this generalization check up, -that if at a distance a short valley was observed to end in a cirque, I -knew at once and long before I came to the valley head that a shoulder -below the schrundline did not exist. At the time this observation was -made its significance was a mystery, but it represents a condition so -constant that it forms one of the striking features of the glacial forms -in the headwater region. - -[Illustration: FIG. 199--Further stages in the development of cirques. -See p. 299 and Fig. 198.] - -The meaning of this feature is represented in Fig. 199, in which three -successive stages in cirque development are shown. In _A_, as displayed -in small valleys or mountainside alcoves which were but temporarily -occupied by snow and ice, or as in all higher valleys during the earlier -stages of the advancing hemicycle of glaciation, snow collects, a short -glacier forms, and a bergschrund develops. As a result of the -concentrated frost action at the base of the bergschrund a rapid -deepening and steepening takes place at _a_. As long as the depth of -snow (or snow and névé) is slight the bergschrund may remain open. But -its existence at this particular point is endangered as the cirque -grows, since the increasing steepness of the slope results in more rapid -snow movement. Greater depth of snow goes hand in hand with increasing -steepness and thus favors the formation of névé and even ice at the -bottom of the moving mass and a constantly accelerated rate of motion. -At the same time the bergschrund should appear higher up for an -independent reason, namely, that it tends to form between a mass of -slight movement and one of greater movement, which change of function, -as already pointed out, would appear to be controlled by change from -snow to névé or ice on the part of the bottom material. - -The first stages in the upward migration of the bergschrund will not -effect a marked change from the original profile, since the converging -slopes, the great thickness of névé and ice at this point, and the steep -gradient all favor powerful erosion. When, however, stage _C_ is -reached, and the bergschrund has retreated to _c"_, a broader terrace -results below the schrundline, the gradient is decreased, the ice and -névé (since they represent a constant discharge) are spread over a -greater area, hence are thinner, and we have the cirque taking on a -compound character with a lower, less steep and an upper, precipitous -section. - -It is clear that a closely jointed and fragile rock might be quarried by -moving ice at _c'-c"_ and the cirque wall extended unbroken to _x_; it -is equally clear that a homogeneous, unjointed granite would offer no -opportunities for glacial plucking and would powerfully resist the much -slower process of abrasion. Thus Gilbert[64] observed the schrundline in -the granites of the Sierra Nevada, which are "in large part -structureless" and my own observations show the schrundline well -developed in the open-jointed granites of the Cordillera Vilcapampa and -wholly absent in the volcanoes of the Maritime Cordillera, where ashes -and cinders, the late products of volcanic action, form the easily -eroded walls of the steep cones. Somewhere between these extremes--lack -of a variety of observations prevents our saying where--the resistance -and the internal structure of the rock will just permit a cirque wall to -extend from _x_ to _c' "_ of Fig. 199. - -A common feature of cirques that finds an explanation in the proposed -hypothesis is the notch that commonly occurs at some point where a -convergence of slopes above the main cirque wall concentrates snow -discharge. It is proposed to call this type the notched cirque. It is -highly significant that these notches are commonly marked by even -steeper descents at the point of discharge into the main cirque than the -remaining portion of the cirque wall, even when the discharge was from a -very small basin and in the form of snow or at the most névé. The excess -of discharge at a point on the basin rim ought to produce the form we -find there under the conditions of snow motion outlined in earlier -paragraphs. It is also noteworthy that it is at such a point of -concentrated discharge that crevasses no sooner open than they are -closed by the advancing snow masses. To my mind the whole action is -eminently representative of the action taking place elsewhere along the -cirque wall on a smaller scale. - -What seems a good test of the explanation of cirques here proposed was -made in those localities in the Maritime Cordillera, where large -snowbanks but not glaciers affect the form of the catchment basins. A -typical case is shown in Fig. 201. As in many other cases we have here a -great lava plateau broken frequently by volcanic cones of variable -composition. Some are of lava, others consist of ashes, still others of -tuff and lava and ashes. At lower elevations on the east, as at 16,000 -feet between Antabamba and Huancarama, evidences of long and powerful -glaciers are both numerous and convincing. But as we rise still higher -the glaciated topography is buried progressively deeper under the -varying products of volcanic action, until finally at the summit of the -lava fields all evidences of glaciation disappear in the greater part of -the country between Huancarama and the main divide. Nevertheless, the -summit forms are in many cases as significantly altered as if they had -been molded by ice. Precipitous cirque walls surround a snow-filled -amphitheater, and the process of deepening goes forward under one's -eyes. No moraines block the basin outlets, no U-shaped valleys lead -forward from them. We have here to do with post-glacial action pure and -simple, the volcanoes having been formed since the close of the -Pleistocene. - -Likewise in the pass on the main divide, the perpetual snow has begun -the recessing of the very recent volcanoes bordering the pass. The -products of snow action, muds and sands up to very coarse gravel, -glaciated in texture with an intermingling of blocks up to six inches in -diameter in the steeper places, are collected into considerable masses -at the snowline, where they form broad sheets of waste so boggy as to be -impassable except by carefully selected routes. No ice action whatever -is visible below the snowline and the snow itself, though wet and -compact, is not underlain by ice. Yet the process of hollowing goes -forward visibly and in time will produce serrate forms. In neither case -is there the faintest sign of a bergschrund; the gradients seem so well -adjusted to the thickness and rate of movement of the snow from point to -point that the marginal crack found in many snowfields is absent. - -The absence of bergschrunds is also noteworthy in many localities where -formerly glaciation took place. This is notoriously the case in the -summit zone of the Cordillera Vilcapampa, where the accumulating snows -of the steep cirque walls tumble down hundreds of feet to gather into -prodigious snowbanks or to form névé fields or glaciers. From the -converging walls the snowfalls keep up an intermittent bombardment of -the lower central snow masses. It is safe to say that if by magic a -bergschrund could be opened on the instant, it would be closed almost -immediately by the impetus supplied by the falling snow masses. The -explanation appears to be that the thicker snow and névé concentrated at -the bottom of the cirque results in a corresponding concentration of -action and effect; and cirque development goes on without reference to a -bergschrund. The chief attraction of the bergschrund hypothesis lies in -the concentration of action at the foot of the cirque wall. But in the -thickening of the snow far beyond the minimum thickness required for -motion at the base of the cirque wall and its change of function with -transformation into névé, we need invoke no other agent. If a -bergschrund forms, its action may take place at the foot of the cirque -wall or high up on the wall, and yet _sapping at the foot of the wall_ -continue. - -[Illustration: THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM DIRECTOR - -LAMBRAMA QUADRANGLE] - -From which we conclude (1) that where frost action occurs at the bottom -of a bergschrund opening to the foot of the cirque wall it aids in the -retreat of the wall; (2) that a sapping action takes place at this point -whether or not a bergschrund exists and that bergschrund action is not a -_necessary_ part of cirque formation; (3) that when a more or less -persistent bergschrund opens on the cirque wall above its foot it tends -to develop a schrundline with a marked terrace below it; (4) that -schrundlines are best developed in the mature stages of topographic -development in the glacial cycle; (5) that the varying rates of snow, -névé, and ice motion at a valley head are the _persistent_ features to -which we must look for topographic variations; (6) that the hypothesis -here proposed is applicable to all cases whether they involve the -presence of snow or névé or ice or any combination of these, and whether -bergschrunds are present or not; and (7) at the same time affords a -reasonable explanation for such variations in forms as the compound -cirque with its schrundline and terrace, the unbroken cirque wall, the -notched cirque, and the recessed, snow-covered mountain slopes -unaffected by ice. - - -ASYMMETRICAL CREST LINES AND ABNORMAL VALLEY PROFILES IN THE CENTRAL -ANDES - -To prove that under similar conditions glacial erosion may be greater -than subaërial denudation quantitative terms must be sought. Only these -will carry conviction to the minds of many opponents of the theory that -ice is a vigorous agent of erosion. Gilbert first showed in the Sierra -Nevada that headwater glaciers eroded more rapidly than nonglacial -agents under comparable topographic and structural conditions.[65] Oddly -enough none of the supporters of opposing theories have replied to his -arguments; instead they have sought evidence from other regions to show -that ice cannot erode rock to an important degree. In this chapter -evidence from the Central Andes, obtained in 1907 and 1911, will be -given to show the correctness of Gilbert's proposition. - -The data will be more easily understood if Gilbert's argument is first -outlined. On the lower slopes of the glaciated Sierra Nevada asymmetry -of form resulted from the presence of ice on one side of each ridge and -its absence on the other (Fig. 200). The glaciers of these lower ridges -were the feeblest in the entire region and were formed on slopes of -small extent; they were also short-lived, since they could have existed -only when glacial conditions had reached a maximum. Let the broken line -in the upper part of the figure represent the preglacial surface and -the solid line beneath it the present surface. It will not matter what -value we give the space between the two lines on the left to express -nonglacial erosion, since had there been no glaciers it would be the -same on both sides of the ridge. The feeble glacier occupying the -right-hand slope was able in a very brief period to erode a depression -far deeper than the normal agents of denudation were able to erode in a -much longer period, i.e., during all of interglacial and postglacial -time. Gilbert concludes: "The visible ice-made hollows, therefore, -represent the local excess of glacial over nonglacial conditions." - -[Illustration: FIG. 200--Diagrammatic cross-section of a ridge glaciated -on one side only; with hypothetical profile (broken line) of preglacial -surface.] - -[Illustration: FIG. 201--Postglacial volcano recessed on shady southern -side by the process of nivation. Absolute elevation 18,000 feet (5,490 -m.), latitude 14° S., Maritime Cordillera, Peru.] - -In the Central Andes are many volcanic peaks and ridges formed since the -last glacial epoch and upon them a remarkable asymmetry has been -developed. Looking southward one may see a smoothly curved, snow-free, -northward-facing slope rising to a crest line which appears as regular -as the slope leading to it. Looking northward one may see by contrast -(Fig. 194) sharp ridges, whose lower crests are serrate, separated by -deeply recessed, snow-filled mountain hollows. Below this highly -dissected zone the slopes are smooth. The smooth slope represents the -work of water; the irregular slopes are the work of snow and ice. The -relation of the north and south slopes is diagrammatically shown in Fig. -201. - -To demonstrate the erosive effects of snow and ice it must be shown: (1) -that the initial slopes of the volcanoes are of postglacial age; (2) -that the asymmetry is not structural; (3) that the snow-free slopes have -not had special protection, as through a more abundant plant cover, more -favorable soil texture, or otherwise. - -Proof of the postglacial origin of the volcanoes studied in this -connection is afforded: (1) by the relation of the flows and the ash and -cinder beds about the bases of the cones to the glacial topography; (2) -by the complete absence of glacial phenomena below the present snowline. -Ascending a marginal valley (Fig. 202), one comes to its head, where two -tributaries, with hanging relations to the main valley, come down from a -maze of lesser valleys and irregular slopes. Glacial features of a -familiar sort are everywhere in evidence until we come to the valley -heads. Cirques, reversed grades, lakes, and striæ are on every hand. But -at altitudes above 17,200 feet, recent volcanic deposits have over large -areas entirely obscured the older glacial topography. The glacier which -occupied the valley of Fig. 202 was more than one-quarter of a mile -wide, the visible portion of its valley is now over six miles long, but -the extreme head of its left-hand tributary is so concealed by volcanic -material that the original length of the glacier cannot be determined. -It was at least ten miles long. From this point southward to the border -of the Maritime Cordillera no evidence of past glaciation was observed, -save at Solimana and Coropuna, where slight changes in the positions of -the glaciers have resulted in the development of terminal moraines a -little below the present limits of the ice. - -From the wide distribution of glacial features along the northeastern -border of the Maritime Cordillera and the general absence of such -features in the higher country farther south, it is concluded that the -last stages of volcanic activity were completed in postglacial time. It -is equally certain, however, that the earlier and greater part of the -volcanic material was ejected before glaciation set in, as shown by the -great depth of the canyons (over 5,000 feet) cut into the lava flows, as -contrasted with the relatively slight filling of coarse material which -was accumulated on their floors in the glacial period and is now in -process of dissection. Physiographic studies throughout the Central -Andes demonstrate both the general distribution of this fill and its -glacial origin. - -So recent are some of the smaller peaks set upon the lava plateau that -forms the greater part of the Maritime Cordillera, that the snows massed -on their shadier slopes have not yet effected any important topographic -changes. The symmetrical peaks of this class are in a few cases so very -recent that they are entirely uneroded. Lava flows and beds of tuff -appear to have originated but yesterday, and shallow lava-dammed lakes -retain their original shore relations. In a few places an older -topography, glacially modified, may still be seen showing through a -veneer of recent ash and cinder deposits, clear evidence that the -loftier parts of the lava plateau were glaciated before the last -volcanic eruption. - -The asymmetry of the peaks and ridges in the Maritime Cordillera cannot -be ascribed to the manner of eruption, since the contrast in declivity -and form is persistently between northern and southern slopes. Strong -and persistent winds from a given direction undoubtedly influence the -form of volcanoes to at least a perceptible degree. In the case in hand -the ejectamenta are ashes, cinders, and the like, which are blown into -the air and have at least a small component of motion down the wind -during both their ascent and descent. The _prevailing_ winds of the high -plateaus are, however, easterly and the strongest winds are from the -west and blow daily, generally in the late afternoon. Both wind -directions are at right angles to the line of asymmetry, and we must, -therefore, rule out the winds as a factor in effecting the slope -contrasts which these mountains display. - -It remains to be seen what influence a covering of vegetation on the -northern slopes might have in protecting them from erosion. The northern -slopes in this latitude (14° S.) receive a much greater quantity of heat -than the southern slopes. Above 18,000 feet (5,490 m.) snow occurs on -the shady southern slopes, but is at least a thousand feet higher on the -northern slopes. It is therefore absent from the northern side of all -but the highest peaks. Thus vegetation on the northern slopes is not -limited by snow. Bunch grass--the characteristic _ichu_ of the mountain -shepherds--scattered spears of smaller grasses, large ground mosses -called _yareta_, and lichens extend to the snowline. This vegetation, -however, is so scattered and thin above 17,500 feet (5,330 m.) that it -exercises no retarding influence on the run-off. Far more important is -the porous nature of the volcanic material, which allows the rainfall to -be absorbed rapidly and to appear in springs on the lower slopes, where -sheets of lava direct it to the surface. - -The asymmetry of the north and south slopes is not, then, the result of -preglacial erosion, of structural conditions, or of special protection -of the northern slopes from erosion. It must be concluded, therefore, -that it is due to the only remaining factor--snow distribution. The -southern slopes are snow-clad, the northern are snow-free--in harmony -with the line of asymmetry. The distribution of the snow is due to the -contrasts between shade and sun temperatures, which find their best -expression in high altitudes and on single peaks of small extent. -Frankland's observations with a black-bulb thermometer _in vacuo_ show -an increase in shade and sun temperatures contrasts of over 40° between -sea level and an elevation of 10,000 feet. Violle's experiments show an -increase of 26 per cent in the intensity of solar radiation between 200 -feet and 16,000 feet elevation. Many other observations up to 16,000 -feet show a rapid increase in the difference between sun and shade -temperatures with increasing elevation. In the region herein described -where the snowline is between 18,000 and 19,000 feet (5,490 to 5,790 m.) -these contrasts are still further heightened, especially since the -semi-arid climate and the consequent long duration of sunshine and low -relative humidity afford the fullest play to the contrasting forces. The -coefficient of absorption of radiant energy by water vapor is 1,900 -times that of air, hence the lower the humidity the more the radiant -energy expended upon the exposed surface and the greater the sun and -shade contrasts. The effect of these temperature contrasts is seen in a -canting of the snowline on individual volcanoes amounting to 1,500 feet -in extreme instances. The average may be placed at 1,000 feet. - -The minimum conditions of snow motion and the bearing of the conclusions -upon the formation of cirques have been described in the chapters -immediately preceding. It is concluded that snow moves upon 20° slopes -if the snow is at least forty feet deep, and that through its motion -under more favorable conditions of greater depth and gradient and the -indirect effects of border melting there is developed a hollow occupied -by the snow. Actual ice is not considered to be a necessary condition of -either movement or erosion. We may at once accept the conclusion that -the invariable association of the cirques and steepened profiles with -snowfields proves that snow is the predominant modifying agent. - -An argument for glacial erosion based on profiles and steep cirque walls -in a volcanic region has peculiar appropriateness in view of the -well-known symmetrical form of the typical volcano. Instead of varied -forms in a region of complex structure long eroded before the appearance -of the ice, we have here simple forms which immediately after their -development were occupied by snow. _Ever since their completion these -cones have been eroded by snow on one side and by water on the other._ -If snow cannot move and if it protects the surface it covers, then this -surface should be uneroded. All such surfaces should stand higher than -the slopes on the opposite aspect eroded by water. But these assumptions -are contrary to fact. The slopes underneath the snow are deeply -recessed; so deeply eroded indeed, that they are bordered by steep -cliffs or cirque walls. The products of erosion also are to some extent -displayed about the border of the snow cover. In strong contrast the -snow-free slopes are so slightly modified that little of their original -symmetry is lost--only a few low hills and shallow valleys have been -formed. - -The measure of the excess of snow erosion over water erosion is -therefore the difference between a northern or water-formed and a -southern or snow-formed profile, Fig. 200. This difference is also shown -in Fig. 201 and from it and the restored initial profiles we conclude -that the rate of water erosion is to that of nivation as 1:3. This ratio -has been derived from numerous observations on cones so recently formed -that the interfluves without question are still intact. - -Thus far only those volcanoes have been considered which have been -modified by nivation. There are, however, many volcanoes which have been -eroded by ice as well as by snow and water. It will be seen at once that -where a great area of snow is tributary to a single valley, the snow -becomes compacted into névé and ice, and that it then erodes at a much -faster rate. Also a new force--plucking--is called into action when ice -is present, and this greatly accelerates the rate of erosion. While it -lies outside the limits of my subject to determine quantitatively the -ratio between water and ice action, it is worth pointing out that by -this method a ratio much in excess of 1:3 is determined, which even in -this rough form is of considerable interest in view of the arguments -based on the protecting influence of both ice and snow. I have, indeed, -avoided the question of ice erosion up to this point and limited myself -to those volcanoes which have been modified by nivation only, since the -result is more striking in view of the all but general absence of data -relating to this form of erosion. - -[Illustration: FIG. 202--Graphic representation of amount of glacial -erosion during the glacial period. In the background are mature slopes -surmounted by recessed asymmetrical peaks. The river entrenched itself -below the mature slopes before it began to aggrade, and, when -aggradation set in, had cut its valley floor to a'-b'-c. By aggradation -the valley floor was raised to a-b while ice occupied the valley head. -By degradation the river has again barely lowered its channel to a'-b', -the ice has disappeared, and the depression of the profile represents -the amount of glacial erosion. - -a'-b'-c = preglacial profile. - -a-b-d-c = present profile. - -b'-d-c-b = total ice erosion in the glacial period. - -a-b = surface of an alluvial valley fill due to - excessive erosion at valley head. - -b-b' = terminal moraine. - -d-c = cirque wall. - -e, e' e" = asymmetrical summits.] - -[Illustration: FIG. 203--A composite sketch to represent general -conditions in the Peruvian Andes. In order to have the actual facts -represented the profiles of this figure were taken from the accompanying -topographic sheets. The main depression on the right and the -corresponding depression of the tributary profiles bear out most -strikingly the conclusions concerning the erosive power of the ice. At -_A_ and _B_ the spurs have been cut off to exhibit the profiles of -tributary valleys. At _2_ and _3_ were tributary glaciers of such size -that they entered the main valley at grade. Lesser tributaries had -floors elevated above those they joined and now have a hanging -character, as just above _2_. _D_ is a matterhorn; _C_ is deeply -recessed by cirques; _E_ represents a peak just below the limit of -glaciation. At _F_ are the undissected post-mature slopes of an earlier -cycle of erosion. _G_ lies on the steep lower slopes formed during the -canyon cycle of erosion. The down-cutting of the stream in the canyon -cycle was generally checked by glaciation and was superseded by -aggradation.] - -If we now turn to the valley profiles of the glaciated portions of the -Peruvian Andes, we shall see the excess of ice over water erosion -expressed in a manner equally convincing. To a thoughtful person it is -one of the most remarkable features of any glaciated region that the -flattest profiles, the marshiest valley flats, and the most strongly -meandering stretches of the streams should occur near the heads of the -valleys. The mountain shepherds recognize this condition and drive -their flocks up from the warmer valley into the mountain recesses, -confident that both distance and elevation will be offset by the -extensive pastures of the finest _ichu_ grass. Indeed, to be near the -grazing grounds of sheep and llamas which are their principal means of -subsistence, the Indians have built their huts at the extraordinarily -lofty elevations of 16,000 to 17,000 feet. - -An examination of a large number of these valleys and the plotting of -their gradients discloses the striking fact that the heads of the -valleys were deeply sunk into the mountains. It is thus possible by -restoring the preglacial profiles to measure with considerable certainty -the excess of ice over water erosion. - -The results are graphically expressed in Fig. 202. It will be seen that -until glacial conditions intervened the stream was flowing on a rock -floor. During the whole of glacial time it was aggrading its rock floor -below _b'_ and forming a deep valley fill. A return to warmer and drier -conditions led to the dissection of the fill and this is now in -progress. The stream has not yet reached its preglacial profile, but it -has almost reached it. We may, therefore, say that the preglacial valley -profile below _b'_ fixes the position of the present profile just as -surely as if the stream had been magically halted in its work at the -beginning of the period of glaciation. There, _b'-d-c-b_ represents the -amount of ice erosion. To be sure the line _b-c_ is inference, but it is -reasonable inference and, whatever position is assigned to it, it cannot -be coincident with _b'-d_, nor can it be anywhere near it. The break in -the valley profile at _b'_ is always marked by a terminal moraine, -regardless of the character of the rock. This is not an accidental but a -causal association. It proves the power of the ice to erode. In glacial -times it eroded the quantity _b-c-d-b'_. This is not an excess of ice -over water erosion, but an absolute measure of ice erosion, since -_a'-b'_ has remained intact. The only possible error arises from the -position assigned _b-c_, and even if we lower it to _b-c'_ (for which we -have no warrant but extreme conservatism) we shall still have left -_b'-c'-d-b_ as a striking value for rock erosion (plucking and abrasion) -by a valley glacier. - -A larger diagram, Fig. 203, represents in fuller detail the topographic -history of the Andes of southern Peru and the relative importance of -glaciation. The broad spurs with grass-covered tops that end in steep -scarps are in wonderful contrast to the serrate profiles and truncated -spurs that lie within the zone of past glaciation. In the one case we -have minute irregularities on a canyon wall of great dimensions; in the -other, more even walls that define a glacial trough with a flat floor. -Before glaciation on a larger scale had set in the right-hand section of -the diagram had a greater relief. It was a residual portion of the -mountain and therefore had greater height also. Glaciers formed upon it -in the Ice Age and glaciation intensified the contrast between it and -the left-hand section; not so much by intensifying the relief as by -diversifying the topographic forms. - -[Illustration: FIG. 204--Topographic map of the Andes between Abancay -and the Pacific Coast at Camaná. Compiled from the seven accompanying -topographic sheets (see Contents, p. xi). Scale 1:1,000,000. Contour -interval 1,000 feet. Longitude west of Greenwich. The Central Ranges of -the Maritime Cordillera are not confined to the area covered by these -names. In the one case the term includes all the ranges between Lambrama -and Huichihua; in the other case, the peaks and ranges from 14° 30' S. -to Mt. Coropuna.] - - - - -APPENDIX A - -SURVEY METHODS EMPLOYED IN THE CONSTRUCTION OF THE SEVEN ACCOMPANYING -TOPOGRAPHIC SHEETS - -BY KAI HENDRIKSEN, TOPOGRAPHER - - -The main part of the topographical outfit consisted of (1) a 4-inch -theodolite, Buff and Buff, the upper part detachable, (2) an 18 x 24 -inch plane-table with Johnson tripod and micro-meteralidade. These -instruments were courteously loaned the expedition by the U. S. Coast -and Geodetic Survey and the U. S. Geological Survey respectively. - -The method of survey planned was a combination of graphic triangulation -and traverse with the micro-meteralidade. All directions were plotted on -the plane-table which was oriented by backsight; distances were -determined by the micro-meteralidade or triangulation, or both combined; -and elevations were obtained by vertical angles. Finally, astronomical -observations, usually to the sun, were taken at intervals of about 60 -miles for latitude and azimuth to check the triangulation. No -observations were made for differences in longitude because this would -probably not have given any reliable result, considering the time and -instruments at our disposal. Because the survey was to follow very -closely the seventy-third meridian west of Greenwich, directions and -distances, checked by latitude and azimuth observations, undoubtedly -afforded far better means of determining the longitude than time -observations. In other words, the time observations made in connection -with azimuth observations were not used for computing longitudinal -differences. Absolute longitude was taken from existing observations of -principal places. - -Principal topographical points were located by from two to four -intersections from the triangulation and plane-table stations; and -elevations were determined by vertical angle measurements. Whenever -practicable, the contours were sketched in the field; the details of the -topography otherwise depend upon a great number of photographs taken by -Professor Bowman from critical stations or other points which it was -possible to locate on the maps. - - -CROSS-SECTION MAP FROM ABANCAY TO CAMANÁ AT THE PACIFIC OCEAN - -Seven sheets. Scale, 1:125,000; contour interval, 200 feet. Datum is -mean sea level. Astronomical control: 5 latitude and 5 azimuth -observations as indicated on the accompanying topographic sheets. - -On September 10th, returning from a reconnaissance survey of the -Pampaconas River, I joined Professor Bowman's party, Dr. Erving acting -as my assistant. We crossed the Cordillera Vilcapampa and the Canyon of -the Apurimac and after a week's rest at Abancay started the topographic -work near Hacienda San Gabriel south of Abancay. Working up the deep -valley of Lambrama, observations for latitude and azimuth were made -midway between Hacienda Matara and Caypi. - -On October 4th we made our camp in newly fallen snow surrounded by -beautiful glacial scenery. The next day on the high plateau, we passed -sharp-crested glaciated peaks; a heavy thunder and hail storm broke out -while I occupied the station at the pass, the storm continuing all the -afternoon--a frequent occurrence. The camp was made 6 miles farther on, -and the next morning I returned to finish the latter station. I -succeeded in sketching the detailed topography just south of the pass, -but shortly after noon, a furious storm arose similar to the one the day -before, and made further topographic work impossible; to get connection -farther on I patiently kept my eye to the eye-piece for more than an -hour after the storm had started, and was fortunate to catch the station -ahead in a single glimpse. I had a similar experience some days later at -station 16,079, Antabamba Quadrangle, on the rim of the high-level puna, -the storm preventing all topographic work and barely allowing a single -moment in which to catch a dim sight of the signals ahead while I kept -my eye steadily at the telescope to be ready for a favorable break in -the heavy clouds and hail. - -At Antabamba we got a new set of Indian carriers, who had orders to -accompany us to Cotahuasi, the next sub-prefectura. Raimondi's map -indicates the distance between the two cities to be 35 miles, but -although nothing definite was stated, we found out in Antabamba that the -distance was considerably longer, and moreover that the entire route lay -at a high altitude. - -From the second day out of Antabamba until Huaynacotas was in sight in -the Cotahuasi Canyon, a distance of 50 miles, the route lay at an -altitude of from 16,000 to 17,630 feet, taking in 5 successive camps at -an altitude from 15,500 to 17,000 feet; 12 successive stations had the -following altitudes: - - 16,379 feet - 16,852 " - 17,104 " - 17,559 " - 17,675 " --highest station occupied. - 17,608 " - 17,633 " - 16,305 " - 17,630 " - 17,128 " - 16,794 " - 16,260 " - -The occupation of these high stations necessitated a great deal of -climbing, doubly hard in this rarefied air, and often on volcanoes with -a surface consisting of bowlders and ash and in the face of violent -hailstorms that made extremely difficult the task of connecting up -observations at successive stations. - -At Cotahuasi a new pack-train was organized, and on October 25th I -ventured to return alone to the high altitudes in order to continue the -topography at the station at 17,633 feet on the summit of the Maritime -Cordillera. Dr. Erving was obliged to leave on October 18th and -Professor Bowman left a week later in order to carry out his plans for a -physiographic study of the coast between Camaná and Mollendo. Philippi -Angulo, a native of Taurisma, a town above Cotahuasi, acted as majordomo -on this journey. Knowing the trail and the camp sites, I was able to -pick out the stations ahead myself, and made good progress, returning to -Cotahuasi on October 29th, three or four days earlier than planned. From -Cotahuasi to the coast I had the assistance of Mr. Watkins. The most -trying part of the last section of high altitude country was the great -Pampa Colorada, crowned by the snow-capped peaks of Solimana and -Coropuna, reaching heights of 20,730 and 21,703 feet respectively. The -passing of this pampa took seven days and we arrived at Chuquibamba on -November 9th. Two circumstances made the work on this stretch peculiarly -difficult--the scarcity of camping places and the high temperature in -the middle of the day, which heated the rarefied air to a degree that -made long-distance shots very strenuous work for the eyes. Although our -base signals were stone piles higher than a man, I was often forced to -keep my eye to the telescope for hours to catch a glimpse of the -signals; lack of time did not allow me to stop the telescope work in the -hottest part of the day. - -The top of Coropuna was intersected from the four stations: 16,344, -15,545, 16,168, and 16,664 feet elevation, the intersections giving a -very small triangular error. The elevation of Mount Coropuna's high peak -as computed from these 4 stations is: - - 21,696 feet - 21,746 " - 21,714 " - 21,657 " - ------ - Mean elevation 21,703 feet above sea level. - -The elevation of Coropuna as derived from these four stations has thus a -mean error of 18 feet (method of least squares) while the elevation of -each of the four stations as carried up from mean sea level through 25 -stations--vertical angles being observed in both directions--has an -estimated mean error of 30 feet. The result of this is a mean error of -35 feet in Coropuna's elevation above mean sea level. - -The latitude is 15° 31' 00" S.; the longitude is 72° 42' 40" W. of -Greenwich, the checking of these two determinations giving a result -unexpectedly close. - -On November 11th azimuth and latitude observations were taken at -Chuquibamba and two days later we arrived at Aplao in the bottom of the -splendid Majes Valley. In the northern part of this valley I was -prevented from doing any plane-table work in the afternoons of four -successive days. A strong gale set in each noon raising a regular -sandstorm, that made seeing almost impossible, and blowing with such a -velocity that it was impossible to set up the plane-table. - -From Hacienda Cantas to Camaná we had to pass the western desert for a -distance of 45 miles. We were told that on the entire distance there was -only one camping place. This was at Jaguey de Majes, where there was a -brook with just enough water for the animals but no fodder. Thus we -faced the necessity of carrying water for ten men and fodder for 14 -animals in excess of the usual cargo; and we were unable to foretell how -many days the topography over the hot desert would require. - -Although plane-table work in the desert was impossible at all except in -the earliest and latest hours of the day, we made regular progress. We -camped three nights at Jaguey and arrived on the fourth day at Las -Lomas. - -The next morning, on November 23rd, at an elevation of 2178 feet near -the crest of the Coast Range, we were repaid for two months of laborious -work by a glorious view of the Pacific Ocean and of the city of Camaná -with her olive gardens in the midst of the desert sand. - -The next day I observed latitude and azimuth at Camaná and in the night -my companion and assistant Mr. Watkins and I returned across the desert -to the railroad at Vitor. - - -CONCLUSIONS - -The planned methods were followed very closely. In two cases only the -plane-table had to be oriented by the magnetic needle, the backsights -not being obtainable because of the impossibility of locating the last -station, passing Indians having removed the signals. - -In one case only the distance between two stations had to be determined -by graphic triangulation exclusively, the base signals having been -destroyed. Otherwise graphic triangulation was used as a check on -distances. - -Vertical angles were always measured in both directions with the -exception of the above-mentioned cases. - -Observations for azimuth were always taken to the sun before and after -noon. The direction used in the azimuth observation was also taken with -the prismatic compass. The mean of the magnetic declination thus found -is: East 8° 30' plus. - -Observations for latitude were taken to the sun by the method of -circum-meridian altitudes, except at the town of Vilcabamba where star -observations were taken. - -As a matter of course, observations to the sun are not so exact as star -observations, especially in low latitudes where one can expect to -observe the near zenith. However, working in high altitudes for long -periods, moving camp every day and often arriving at camp 2 to 4 hours -after sunset, I found it essential to have undisturbed rest at night. It -was beyond my capacity to spend an hour or two of the night in finding -the meridian and in making the observation. Furthermore, the astronomic -observations were to check the topography mainly, the latter being the -most exact method with the outfit at hand. - -The following table contains the comparisons between the latitude -stations as located on the map and by observation: - - Map Observation - Camaná Quadrangle S 16° 37' 34" 16° 37' 34"[66] - Coropuna, station 9,691S 15° 48' 30" (15° 51' 44") - Cotahuasi, " 12,588S 15° 11' 40" 15° 12' 30" - La Cumbre, " 16,852S 14° 28' 10" 14° 29' 46" - Lambrama, " 8,341S 13° 43' 18" 13° 43' 14" - -The other observations, with the exception of the one on the Coropuna -Quadrangle, check probably as well as can be expected with the small and -light outfit which we used, and under the exceptionally hard conditions -of work. The observation on the Coropuna Quadrangle just south of -Chuquibamba is, however, too much out. An explanation for this is that -the meridian zenith distance was 1° 23' 12" only (in this case the exact -formula was used in computing). Of course, an error or an accumulation -of errors might have been made in the distances taken by the -micrometer-alidade, but the first cause of error mentioned is the more -probable, and this is indicated also by the fact that the location on -the top of Mount Coropuna checks closely with the one determined in an -entirely independent way by the railroad engineers. - -For the cross-section map from Abancay to Camaná, the following -statistics are desirable: - -Micrometer traverse and graphic triangulation, with contours, field -scale 1:90,000. - - Total time required, days 40.5 - Average distance per days in miles 7.5 - Average number of plane-table stations occupied per day 1.5 - Average area per day in square miles 38. - Located points per square mile 0.25 - Approximate elevations in excess of above, per square mile 0.25 - Highest station occupied, feet above sea level 17,675. - Highest point located, feet above sea level 21,703. - - - - -APPENDIX B - -FOSSIL DETERMINATIONS - - -A few fossil collections were gathered in order that age determinations -might be made. With the following identifications I have included a few -fossils (I and II) collected by W. R. Rumbold and put into my hands in -1907. The Silurian is from a Bolivian locality south of La Paz but in -the great belt of shales, slates, and schists which forms one of the -oldest sedimentary series in the Eastern Andes of Peru as well as -Bolivia. While no fossils were found in this series in Peru the rocks -are provisionally referred to the Silurian. Fossil-bearing Carboniferous -overlies them but no other indication of their age was obtained save -their general position in the belt of schists already mentioned. I am -indebted to Professor Charles Schuchert of Yale University for the -following determinations. - - -I. _Silurian_ - - San Roque Mine, southwest slope of Santa Vela Cruz, Canton Ichocu, Province - Inquisivi, Bolivia. - - Sent by William R. Rumbold in 1907. - - _Climacograptus?_ - _Pholidops trombetana_ Clarke? - _Chonetes striatellus_ (Dalman). - _Atrypa marginalis_ (Dalman)? - _Coelospira_ n. sp. - _Ctenodonta_, 2 or more species. - _Hyolithes._ - _Kloedenia._ - _Calymene?_ - _Dalmanites_, a large species with a terminal tail spine. - _Acidaspis._ - -These fossils indicate unmistakably Silurian and probably Middle -Silurian. As all are from blue-black shales, brachiopods are the rarer -fossils, while bivalves and trilobites are the common forms. The faunal -aspect does not suggest relationship with that of Brazil as described by -J. M. Clarke and not at all with that of North America. I believe this -is the first time that Silurian fossils have been discovered in the high -Andes. - - -II. LOWER DEVONIAN - -Near north end of Lake Titicaca. - - _Leptocoelia flabellites_ (Conrad), very common. - _Atrypa reticularis_ (Linnæus)? - -This is a part of the well-known and widely distributed Lower Devonian -fauna of the southern hemisphere. - - -III. _Upper Carboniferous_ - -All of the Upper Carboniferous lots of fossils represent the well-known -South American fauna first noted by d'Orbigny in 1842, and later added -to by Orville Derby. The time represented is the equivalent of the -Pennsylvanian of North America. - -Huascatay between Pasaje and Huancarama. - - Crinoidal limestone. - Trepostomata Bryozoa. - _Polypora._ Common. - _Streptorhynchus hallianus_ Derby. Common. - _Chonetes glaber_ Geinitz. Rare. - _Productus humboldti_ d'Orb. Rare. - " _cora_ d'Orb. Rare. - " _chandlessii_ Derby. - " sp. undet. Common. - " sp. undet. " - _Spirifer condor_ d'Orb. Common. - _Hustedia mormoni_ (Marcou). Rare. - _Seminula argentea_ (Shepard). " - - Pampaconas, Pampaconas valley near Vilcabamba. - - _Lophophyllum?_ - _Rhombopora_, etc. - _Productus._ - _Camarophoria._ Common. - _Spirifer condor_ d'Orb. - _Hustedia mormoni_ (Marcou). - _Euomphalus._ Large form. - - Pongo de Mainique. Extreme eastern edge of Peruvian Cordillera. - - _Lophophyllum._ - _Productus chandlessii_ Derby. - " _cora_ d'Orb. - _Orthotetes correanus_ (Derby). - _Spirifer condor_ d'Orb. - - River bowlders and stones of Urubamba river, just beyond eastern edge of - Cordillera at mouth of Ticumpinea river. (Detached and transported by stream - action from the Upper Carboniferous at Pongo de Mainique.) - - Mostly Trepostomata Bryozoa. - Many _Productus_ spines. - _Productus cora_ d'Orb. - _Camarophoria_. Same as at Pampaconas. - _Productus_ sp. undet. - - Cotahuasi A. - - _Lophophyllum._ - _Productus peruvianus_ d'Orb. - " sp. undet. - _Camarophoria._ - _Pugnax_ near _utah_ (Marcou). - _Seminula argentea_ (Shepard)? - - Cotahuasi B. - - _Productus cora_ d'Orb. - " near _semireticulatus_ (Martin). - - - IV. _Comanchian or Lower Cretaceous_ - - Near Chuquibambilla. - - _Pecten_ near _quadricostatus_ Sowerby. - Undet. bivalves and gastropods. - The echinid _Laganum? colombianum_ d'Orb. A clypeasterid. - -This Lower Cretaceous locality is evidently of the same horizon as that -of Colombia illustrated by d'Orbigny in 1842 and described on pages -63-105. - - - - -APPENDIX C - -KEY TO PLACE NAMES - - -Abancay, town, lat. 12° 35', Figs. 20, 204. - -Abra Tocate, pass, between Yavero and Urubamba valleys, - leaving latter at Rosalina, (Fig. 8). - _See also_ Fig. 55. - -Anta, town, lat. 13° 30', Fig. 20. - -Antabamba, town, lat. 14° 20', Figs. 20, 204. - -Aplao, town, lat. 16°, Figs. 20, 204. - -Apurimac, river, Fig. 20. - -Arequipa, town, lat. 16° 30', Fig. 66. - -Arica, town, northern Chile, lat. 18° 30'. - -Arma, river, tributary of Apurimac, lat. 13° 25', (Fig. 20); - tributary of Ocoña, lat. 15° 30', (Fig. 20). - -Arma, village, lat. 13° 15', Fig. 20. - _See also_ Fig. 140. - -Auquibamba, hacienda, lat. 13° 40', Fig. 204. - - -Callao, town, lat. 12°, Fig. 66. - -Camaná, town, lat. 16° 40', Figs. 20, 66, 204. - -Camisea, river, tributary of Urubamba entering from right, lat. 11° 15'. - -Camp 13, lat. 14° 30'. - -Cantas, hacienda, lat. 16° 15', Fig. 204. - -Caraveli, town, lat. 16°, Fig. 66. - -Catacaos, town, lat. 5° 30', Fig. 66. - -Caylloma, town and mines, lat. 15° 30', Fig. 66. - -Caypi, village, lat. 13° 45'. - -Central Ranges, lat. 14°, Fig. 20. - _See also_ Fig. 157. - -Cerro Azul, town, lat. 13°, Fig. 66. - -Chachani, mt., overlooking Arequipa, lat. 16° 30', (Fig. 66). - -Chaupimayu, river, tributary of Urubamba entering at Sahuayaco, _q.v._ - -Chili, river, tributary of Vitor River, lat. 16° 30', (Fig. 66). - -Chinche, hacienda, Urubamba Valley above Santa Ana, lat. 13°, (Fig. 20). - -Chira, river, lat. 5°, Fig. 66. - -Choclococha, lake, lat. 13° 30', Figs. 66, 68. - -Choqquequirau, ruins, canyon of Apurimac above junction of Pachachaca - River, lat. 13° 25', (Fig. 20). - -Choquetira, village, lat. 13° 20', Fig. 20. - _See also_ Fig. 136. - -Chosica, village, lat. 12°, Fig. 66. - -Chuquibamba, town, lat. 15° 50', Figs. 20, 204. - -Chuquibambilla, village, lat. 14°, Figs. 20, 204. - -Chuquito, pass, Cordillera Vilcapampa between Arma and Vilcabamba - valleys, lat. 13° 10', (Fig. 20). - _See also_ Fig. 139. - -Coast Range, Figs. 66, 204. - -Cochabamba, city, Bolivia, lat. 17° 20', long. 66° 20'. - -Colorada, pampa, lat. 15° 30', Fig. 204. - -Colpani, village, lower end of Canyon of Torontoy (Urubamba River), - lat. 13° 10'. _See_ Fig. 158. - -Copacavana, village, Bolivia, lat. 16° 10', long. 69° 10'. - -Coribeni, river, lat. 12° 40', Fig. 8. - -Coropuna, mt., lat. 15° 30', Figs. 20, 204. - -Corralpata, village, Apurimac Valley near Incahuasi. - -Cosos, village, lat. 16°, Fig. 204. - -Cotabambas, town, Apurimac Valley, lat. 13° 45', (Fig. 20). - -Cotahuasi, town, lat. 15° 10', Figs. 20, 204. - -Cuzco, city, lat. 13° 30', Fig. 20. - - -Echarati, hacienda, on the Urubamba River between Santa Ana and - Rosalina, lat. 12° 40'. - _See_ inset map, Fig. 8, _and also_ Fig. 54. - - -Huadquiña, hacienda, Urubamba River above junction with Vilcabamba, - lat. 13° 10', (Fig. 20). - _See also_ Fig. 158. - -Huadquirca, village, lat. 14° 15', Figs. 20, 204. - -Huaipo, lake, north of Anta, lat. 13° 25', (Fig. 20). - -Huambo, village, left bank Pachachaca River between Huancarama - and Pasaje, lat. 13° 35', (Fig. 20). - -Huancarama, town, lat. 13° 40', Fig. 20. - -Huancarqui, village, lat. 16° 5', Fig. 204. - -Huascatay, village, left bank of Apurimac above Pasaje, - lat. 13° 30', (Fig. 20). - -Huaynacotas, village, lat. 15° 10', Fig. 204. - -Huichihua, village, lat. 14° 10', Fig. 204. - - -(Tablazo de) Ica, plateau, lat. 14°-15° 30', Fig. 66. - -Ica, town, lat. 14°, Figs. 66, 67. - -Incahuasi, village, lat. 13° 20', Fig. 20. - -Iquique, town, northern Chile, lat. 20° 15'. - -(Pampa de) Islay, south of Vitor River, (Fig. 66). - - -Jaguey, village, Pampa de Sihuas, _q.v._ - - -La Joya, pampa, station on Mollendo-Puno R.R., 16° 40', (Fig. 66). - -Lambrama, village, lat. 12° 50', Fig. 20. - -Lima, city, lat. 12°, Fig. 66. - - -Machu Picchu, ruins, gorge of Torontoy, _q.v._, lat. 13° 10'. - -Majes, river, Fig. 204. - -Manugali, river, tributary of Urubamba entering from left - above Puviriari River, lat. 12° 20', (Fig. 8). - -Maritime Cordillera, Fig. 204. - -Matara, village, lat. 14° 20', Fig. 204. - -(El) Misti, mt., lat. 16° 30', Fig. 66. - -Mollendo, town, lat. 17°, Fig. 66. - -Moquegua, town, lat. 17°, Fig. 66. - -Morococha, mines, lat. 11° 45', Fig. 66. - -Mulanquiato, settlement, lat. 12° 10', Fig. 8. - - -Occobamba, river, uniting with Yanatili, _q.v._ - -Ocoña, river, lat. 15°-16° 30', Figs. 20, 66. - -Ollantaytambo, village. Urubamba River below Urubamba town, - lat. 13° 15', (Fig. 20), _and see_ inset map, Fig. 8. - - -Pabellon, hacienda, Urubamba River above Rosalina, (Fig. 20). - _See also_ Fig. 55. - -Pacasmayo, town, lat. 7° 30', Fig. 66. - -Pachatusca (Pachatusun), mt., overlooking Cuzco to northeast, lat. 13° 30'. - -Pachitea, river, tributary of Ucayali entering from left, lat. 8° 50'. - -Paita, town, lat. 5°, Fig. 66. - -Pampacolea, village, south of Coropuna, _q.v._ - -Pampaconas, river, known in lower course as Cosireni, - tributary of Urubamba River, (Fig. 8). - Source in Cordillera Vilcapampa west of Vilcabamba. - -Pampas, river, tributary of Apurimac entering from left, lat. 13° 20'. - -Panta, mt., Cordillera Vilcapampa, northwest of Arma, lat. 13° 15', (Fig. 20). - _See also_ Fig. 136. - -Panticalla, pass, Urubamba Valley above Torontoy, lat. 13° 10'. - -Pasaje, hacienda and ferry, lat. 13° 30', Fig. 20. - -Paucartambo (Yavero), river, _q.v._ - -Paucartambo, town, head of Paucartambo (Yavero) River, - lat. 13° 20', long. 71° 40'. Inset map, Fig. 8. - -Pichu-Pichu, mt., overlooking Arequipa, lat. 16°, (Fig. 66). - -Pilcopata, river, tributary of Upper Madre de Dios - east of Paucartambo, lat. 13°. - -Piñi-piñi, river, tributary of Upper Madre de Dios - east of Paucartambo, lat. 13°. - -Pisco, town, lat. 14°, Fig. 66. - -Piura, river, lat. 5°-6°, Fig. 66. - -Piura, town, lat. 5° 30', Fig. 66. - -Pomareni, river, lat. 12°, Fig. 8. - -Pongo de Mainique, rapids, lat. 12°, Fig. 8. - -Pucamoco, hacienda, Urubamba River, between Santa Ana and Rosalina, (Fig. 20). - -Puquiura, village, lat. 13° 5', Fig. 20. - _See also_ Fig. 158. Distinguish Puqura in Anta basin near Cuzco. - -Puqura, village, Anta basin, east of Anta, lat. 13° 30', (Fig. 20). - - -Quilca, town, lat. 16° 40', Fig. 66. - -Quillagua, village, northern Chile, lat. 21° 30', long. 69° 35'. - - -Rosalina, settlement, lat. 12° 35', Fig. 8. - _See also_ Fig. 20. - - -Sahuayaco, hacienda, Urubamba Valley above Rosalina, (Fig. 20). - _See also_ Fig. 55. - -Salamanca, town, lat. 15° 30', Fig. 20. - -Salaverry, town, lat. 8°, Fig. 66. - -Salcantay, mt., lat. 13° 20', Fig. 20. - -San Miguel, bridge, canyon of Torontoy near Machu Picchu, lat. 13° 10'. - -Santa Ana, hacienda, lat. 12° 50', Fig. 20. - -Santa Ana, river, name applied to the Urubamba in the - region about hacienda Santa Ana. - -Santa Lucia, mines, lat. 16°, Fig. 66. - -Santo Anato, hacienda, La Sama's hut, 12° 35', Fig. 8. - -Sihuas, Pampa de, lat. 16° 30', Fig. 204. - -Sillilica, Cordillera, east of Iquique, northern Chile. - -Sintulini, rapids of Urubamba River above junction of - Pomareni, lat. 12° 10', (Fig. 8). - -Sirialo, river, lat. 12° 40', Fig. 8. - -Soiroccocha, mt., Cordillera Vilcapampa north of Arma, - lat. 13° 15', (Fig. 20). - -Solimana, mt., lat. 15° 20', Fig. 204. - -Soray, mt., Cordillera Vilcapampa, southeast of Mt. Salcantay, - lat. 13° 20', (Fig. 20). - -Sotospampa, village, near Lambrama, lat. 13° 50', (Fig. 204). - -Sullana, town, Chira River, lat. 5°, (Fig. 66). - - -Taurisma, village, lat. 15° 10', Fig. 204. - -Ticumpinea, river, tributary of Urubamba entering from right - below Pongo de Mainique, lat. 11° 50', (Fig. 8). - -Timpia, river, tributary of Urubamba entering from right, lat. 11° 45'. - -Tono, river, tributary of Upper Madre de Dios, east of Paucartambo, lat. 13°. - -Torontoy, canyon of the Urubamba between the villages of Torontoy - and Colpani, lat. 13° 10'-13° 15'. - -Torontoy, village at the head of the canyon of the same name, lat. 13° 15'. - _See_ inset map, Fig. 8. - -Tumbez, town, lat. 4° 30', Fig. 66. - -Tunari, Cerro de, mt., northwest of Cochabamba, _q.v._ - - -Urubamba, river, Fig. 20. - -Urubamba, town, lat. 13° 20', Fig. 20. - - -Vilcabamba, river, tributary of Urubamba River entering from - left above Santa Ana, lat. 13°, Fig. 8. - _See also_ Fig. 158. - -Vilcabamba, village, lat. 13° 5', Fig. 20. - _See also_ Fig. 158. - -Vilcanota, Cordillera, southern Peru. - -Vilcanota, river, name applied to Urubamba above lat. of - Cuzco, 13° 30', (Fig. 20). - -Vilcapampa, Cordillera, lat. 13° 20', Fig. 20. - -Vilque, town, southern Peru, lat. 15° 50', long. 70° 30'. - -Vitor, pampa, lat. 16° 30', Fig. 66. - -Vitor, river, Fig. 66. - - -Yanahuara, pass, between Urubamba and Yanatili valleys, lat. 13° 10'. - -Yanatili, river, tributary of Urubamba entering from right - above Rosalina, (Fig. 20). - _See also_ Fig. 65. - -Yavero (Paucartambo), river, tributary of Urubamba entering - from right, lat. 12° 10', Fig. 8. - -Yavero, settlement, at junction of Yavero and Urubamba - rivers, lat. 12° 10', Fig. 8. - -Yunguyo, town, southern Peru, lat. 16° 20', long. 69° 10'. - -Yuyato, river, lat. 12° 5', Fig. 8. - - - - -INDEX - - -Abancay, 32, 62, 64, 78, 92, 93, 181, 189, 221, 243; - suppressing a revolution, 89-91; - temperature curve (diagr.), opp. p. 180 - -Abancay basin, 154 - -Abancay to Camaná cross-section map, work, observation and statistics, 315 - -Abra Tocate, 73, 80, 81; - topography and vegetation from (ill.), opp. p. 19 - -Abra de Malaga, 276 - -Acosta, 205 - -Adams, G. I., 255 - -Agriculture, 74-76, 152 - -Aguardiente, 74. _See_ Brandy - -Alcohol, 5, 6 - -Alluvial fans, 60-63, 70, 270 - -Alluvial fill, 270-273; - view in Majes Valley (ill.), opp. p. 230 - -Alpacas, 5, 52 - -Alto de los Huesos (ill.), opp. p. 7 - -Amazon basin, Humboldt's dream of conquest, 33-35; - Indian tribes, 36 - -Amazonia, 20, 26 - -Ancachs, 171 - -Andahuaylas, 89 - -Andrews, A, C., 295 - -Angulo, Philippi, 317 - -Anta, 187, 189, 190 - -Anta basin, 62, 108, 197; - geology, 250; - view looking north from hill near Anta (ill.), opp. p. 184 - -Antabamba, 52, 53, 95, 96, 99, 101, 189, 197, 243, 303, 316; - Governor, 95-99, 100-101; - Lieutenant Governor, 96-99, 101; - sketch section, 243 - -Antabamba Canyon, view across (ill.), opp. p. 106 - -Antabamba Quadrangle, 316, opp. p. 282 (topog. sheet) - -Antabamba region, geologic sketch map and section, 245 - -Antabamba Valley, 96 - -"Antis," 39 - -Aplao, 106, 115, 116, 181, 226, 231, 255, 256, 257, 273, 318; - composite structure section (diagr.), 259; - temperature curve (diagr.), 181 - -Aplao Quadrangle (topog. sheet), opp. p. 120 - -Appendix A, 315 - -Appendix B, 321 - -Appendix C, 324 - -Apurimac, 51, 57, 60, 94, 153, 154; - crossing at Pasaje (ills.), opp. p. 91; - regional diagram of canyoned country, 58 - -Apurimac Canyon, 189; - cloud belt (ill.), opp. p. 150 - -Arequipa, 52, 89, 92, 117, 120, 137, 284; - glacial features near (sketches), 280 - -Argentina, 93 - -Arica, 130, 132, 198 - -Arma, 67, 189, 212-214 - -Arrieros, Pampa de, 280 - -Asymmetrical peaks (ill.), opp. p. 281 - -Asymmetry, 305-313; - cross-section of ridge (diagr.), 306; - postglacial volcano (diagr.), 306 - -Auquibamba, 93 - -Avalanches, 290 - - -Bailey, S. I., 284 - -Bandits, 95 - -Basins, 60, 154; - regional diagram, 61; - climatic cross-section (diagr.), 62 - -Batholith, Vilcapampa, 215-224 - -Belaunde brothers, 116 - -Bergschrunds, 294-305 - -Bingham, Hiram, ix, 104, 157 - -Block diagram of physiography of Andes, 186 - -Boatmen, Indian, 13 - -Bogotá, Cordillera of, 205 - -Bolivia, 93, 176, 190, 193, 195, 240, 241, 249, 322; - snowline, 275-277 - -Bolivian boundary, 68 - -Border valleys of the Eastern Andes, 68-87 - -Borneo, 206 - -Bowman, Isaiah, 8, 316 - -Brandy, 74, 75, 76, 82-83 - -Bravo, José, 245 - -Bumstead, A. H., ix - - -Cacao, 74, 83 - -Cacti, 150; - arboreal (ill.), opp. p. 90 - -Calchaquí Valley, 250 - -Callao, 118; - cloudiness (with diagr.), 133; - temperature (with diagr.), 126-129; - wind roses (diagrs.), 128 - -Camaná, 21, 112, 115, 116, 117, 118, 140-141, 147, 181, - 225, 226, 227, 266, 318; - coastal Tertiary, 253, 254; - plain of, 229; - temperature curve (diagr.), 181 - -Camaná Quadrangle (topog. sheet), opp. p. 114 - -Camaná Valley, 257 - -Camaná-Vitor region, 117 - -Camino del Peñon, 110 - -Camisea, 36 - -Camp 13, 100, 180, 181; - temperature curve (diagr.), 180 - -Campas, 37 - -Canals for bringing water, 59, 60, 155; - projected, Maritime Cordillera (diagr.), 118 - -Cantas, 115, 116, 226, 253, 257, 273, 318 - -Canyon walls (ills.), opp. p. 218 - -Canyoned country, regional diagram, 58; - valley climates (diagr.), 59 - -Canyons, 60, 72, 73, 197, 219; - Majes River (ill.), opp. p. 230; - topographic conditions before formation of deep - canyons in Maritime Cordillera (ill.), opp. p. 184 - -Caraveli, climate data, 134-136; - wind roses (diagrs.), 136 - -Carboniferous fossils, 323 - -Carboniferous strata, 241-247; - hypothetical distribution of land and sea (diagr.), 246 - -Cashibos, 37 - -Catacaos, 119 - -Cattle tracks (ill.), opp. p. 226 - -Caucho, 29 - -Caylloma, 164, 165 - -Caypi, 316 - -Central Ranges, asymmetrical peaks (ill.), opp. p. 281; - glacial features with lateral moraines (ill.), opp. p. 269; - glacial topography between Lambrama and Antabamba (ill.), opp. p. 280; - steep cirque walls (ill.), opp. p. 286 - -Cerro Azul, 118 - -Cerro de Tunari, 176 - -Chachani, 280, 284 - -Chanchamayo, 77 - -Character. _See_ Human character - -Chaupimayu Valley, 77 - -_Chicha_, 86 - -Chile, 130, 132, 193, 260 - -Chili River, 120 - -Chili Valley, opp. p. 7 (ill.), 117 - -Chimborazo, 281 - -Chinche, 271, 272 - -Chira River, depth diagram, 119, 120 - -Chirumbia, 12 - -Choclococha, Lake, 120 - -Chonta Campas, 37 - -Choqquequirau, 154 - -Choquetira, 66, 67, 211; - bowldery fill below, 269; - glacial features, 206-207 - -Choquetira Valley, moraine, (ill.), opp. p. 208 - -Chosica, 136, 137; - cloudiness (diagr.), 138 - -_Chuño_, 57 - -Chuntaguirus, 41 - -Chuquibamba, 54, 72, 107, 110, 111, 112, 115, 116, 273, 317-319; - sediments, 258 - -Chuquibambilla, 53, 189, 220, 221, 222, 236, 243; - alluvial fill (diagr.), 272; - Carboniferous, 244; - fossils, 323 - -Chuquito pass, crossing (ill.), opp. p. 7; - glacial trough (ill.), opp. p. 205 - -Cirque walls, steep (ill.), opp. p. 286 - -Cirques, 294-305; - development (diagr.), 300; - development, further stages (diagr.), 301; - mode of formation (diagr.), 297 - -Clarke, J. M., 321 - -Clearing in forest (ill.), opp. p. 25 - -Climate, coast, 125-147; - eastern border, 147-153; - Inter-Andean valleys, 153-155; - _see also_ Meteorological records - -Climatic belts, 121-122; - map, 123 - -Climatology, 121-156 - -Cliza, 276 - -Cloud-banners, 16 - -Cloud belt, 143, opp, p. 150 (ill.) - -Cloudiness, 132; - Callao (with diagr.), 133; - desert station near Caraveli (diagrs.), 137; - Machu Picchu, 160; - Santa Lucia (diagr.), 169 - -Clouds, Inter-Andean Valley, 155; - Santa Ana (ill.), opp. p. 180; - Santa Lucia, 168; - types on eastern border of Andes (diagrs.), 148; - _see also_ Fog - -Coast Range, 111, 113, 114, 116, 118, 225-232; - climate, 122-147; - direction, 267; - diagram to show progressive lowering of saturation - temperature in a desert, 127; - geology, 258; - view between Mollendo and Arequipa in June (ill.), opp. p. 226; - wet and dry seasons (diagrs.), 132 - -Coastal belt, map of irrigated and irrigable land, 113 - -Coastal desert, 110-120; - regional diagram of physical relations, 112; - _see also_ Deserts - -Coastal planter, 6 - -Coastal region, topographic and climatic provinces (diagr.), 125 - -Coastal terraces, 225-232 - -Coca, 74, 77, 82-83 - -Coca seed beds (ill.), opp. p. 74 - -Cochabamba, 93; - temperature (diagrs. of ranges), insert opp. p. 178; - weather data, 176-178 - -Cochabamba Indians, 276 - -Colombia, 205 - -Colorada, Pampa de, 114, 317 - -Colpani, 72, 215, 216, 222, 223; - from ice to sugar cane (ill.), opp. p. 3 - -Comanchian fossils, 323 - -Cómas, 155 - -Compañia Gomera de Mainique, 29, 31, 32 - -Concession plan, 29 - -Conibos, 44 - -_Contador_, 84-85 - -Copacavana, 176 - -Cordilleras, 4, 6, 20, 197 - -Coribeni, 15 - -Corn, 57, 59, 62 - -Coropuna, 109, 110, 112, 202, 253, 317, 319; - elevation, 317; - glaciation, 307; - snowline, 283-285 - -Coropuna expedition, 104 - -Coropuna Quadrangle, 197, opp. p. 188 (topog. sheet), 319 - -Corralpata, 51, 59 - -Cosos, 231 - -Cotabambas, 78 - -Cotahuasi, 4, 5, 52, 54, 60, 97, 101, 103, 104, 180, 197, 199, 316, 317; - alluvial fill, 272; - fossils, 322; - geologic sketch maps and cross-section, 247; - rug weaver (ill.), opp. p. 68; - snowline above, 282-283; - temperature curve (diagr.), 180; - view (ill.), opp. p. 57 - -Cotahuasi Canyon, 247, 248, 316 - -Cotahuasi Quadrangle (topog. sheet), opp. p. 192 - -Cotahuasi Valley, geology, 258 - -Cotton, 76, 116, 117 - -Crest lines, asymmetrical, 305-313 - -Cretaceous formations, 247-251 - -Cretaceous fossils, 323 - -Crucero Alto, 188 - -Cuzco, 8, 10, 21, 52, 62, 63, 92, 102, 107, 193, 197; - railroad to Santa Ana, 69-70; - snow, 276; - view (ill.), opp. p. 66 - -Cuzco basin, 61, 62, 154, 251; - slopes at outlet (diagr.), 185 - - -Deformations. _See_ Intrusions - -Derby, Orville, 322 - -Desaguadero Valley, 193 - -Deserts, cloudiness (diagrs.), 137; - rain, 138-140; - sea-breeze in, 132; - tropical forest, 36-37; - wind roses (diagrs.), 136 - -Diagrams. _See_ Regional diagrams - -Dikes, 223 - -Drunkenness, 103, 105-106, 108 - -Dry valleys, 114-115 - -Dunes, 114, 254; - Majes Valley, 262-267; - movement, 132; - superimposed (diagrs.), 265 - -Duque, Señor, 78 - - -Eastern Andes, 204-224; - regional diagram, 22 - -Eastern border, climate, 147-153 - -Eastern valley planter, 3 - -Eastern valleys, 68-87; - climate cross-section (diagr.), 79 - -Echarati, 10, 77, 78, 80, 82; - plantation scene (ill.), opp. p. 75 - -Ecuador volcanoes, 281 - -Epiphyte (ill.), opp. p. 78 - -Erdis, E. C., 158 - -Erosion, 192-195, 210, 211, 305; - _see also_ Glacial erosion; Nivation - -Erving, Dr. W. G., 13, 101, 316, 317 - - -_Faena_ Indians, 75, 83-87 - -Feasts and fairs, 175-176 - -Ferries, 147 - -Fig tree (ill.), opp. p. 75 - -Floods, 151 - -Fog, 132, 139, 143; - conditions along coast from Camaná to Mollendo, 144-145; - _see also_ Clouds - -Forest dweller, 1 - -Forest Indians. _See_ Machigangas - -Forests, clearing (ill.), opp. p. 25; - dense ground cover, trees, epiphytes, and parasites (ill.), opp. p. 155; - moss-draped trees (ill.), opp. p. 24; - mountain, 148-153; - mule trail (ill.), opp. p. 18; - tropical, near Pabellon (ill.), opp. p. 150; - tropical vegetation (ill.), opp. p. 18; - type at Sahuayaco (ill.), opp. p. 90 - -Fossils, 245, 321; - list of, by geologic periods and localities, 321 - -Frankland, 278, 309 - -Frost line, 56-57 - - -Garua, 132 - -Geographical basis of revolutions and of human character, 88-109 - -Geologic dates, 195-196; - Majes Valley, 258, 261; - west coast fault, 248-249 - -Geologic development. _See_ Physiographic and geologic development - -Gilbert, G. K., 300, 302, 305 - -Glacial deposits, 268 - -Glacial erosion, Central Andes, 305-313; - composite sketch of general conditions, 312; - graphic representation of amount during glacial period, 311 - -Glacial features, 274-313; - Arequipa (sketches), 280; - Central Ranges; lateral moraines (ill.), opp. p. 269; - eastern slopes of Cordillera Vilcapampa (map), 210 - -Glacial retreat, 208-214 - -Glacial sculpture, heart of the Cordillera Vilcapampa (map), 212; - southwestern flank of Cordillera Vilcapampa (map), 207 - -Glacial topography between Lambrama and Antabamba (ill.), opp. p. 280; - Maritime Cordillera, north of divide on 73d meridian (ill.), opp. p. 281 - -Glacial trough, view near Chuquito pass (ill.), opp. p. 208 - -Glaciation, 64, 271; - Sierra Nevada, 305; - Vilcapampa, 204-214; - Western Andes, 202 - -Glaciers, Panta Mountain (ill.), opp. p. 287; - view (ill.), opp. p. 205 - -Gomara, 34 - -Gonzales, Señor, 78 - -Government, bad, 95 - -Gran Pajonal, 37 - -Granite, 215-224; - _see also_ Intrusions - -Grass (ill.), opp. p. 154 - -Gregory, J. W., 205 - - -_Hacendado_, 55, 60 - -_Haciendas_, 78, 83, 86 - -Hann, J., 126, 176, 278 - -Hendriksen, Kai, 98, 315 - -Hettner, 205 - -Hevea, 29 - -Highest habitations in the world, 52, 96; - regional diagram of, 50; - stone hut (ill.), opp. p. 48 - -Highland shepherd, 4 - -Highlands, 46 - -Hobbs, W. H., 286, 287 - -Horses, 66, opp. p. 91 (ill.) - -Huadquiña, 70, 71, 72, 75, 82, 86, 219; - hacienda (ill.), opp. p. 73; - terraces, 272 - -Huadquirca, 243 - -Huaipo, Lake, 250, 251 - -Huallaga basin, 153 - -Huambo, 243 - -Huancarama, 64, 87, 189, 243, 303; - view (ill.), opp. p. 106 - -Huancarqui, 257 - -Huari, 176 - -Huascatay, 189, 242, 243; - Carboniferous, 244; - fossils, 322 - -Huasco basin, 275 - -Huaynacotas, 103, 316; - terraced valley slope (ill.), opp. p. 56; - terraced valley slopes (ill.), opp. p. 199 - -Huichihua, 278; alluvial fill (diagr.), 272; - (ill.), opp. p. 67 - -Human character, geographic basis, 88-109 - -Humboldt, 33-35, 286 - -Humboldt Current, 126, 143 - -Huts, 103; - highest in Peru (ill.), opp. p. 48; - shepherds', 47, 48, 52, 55 - - -Ica Valley, 120; - irrigated and irrigable land (diagr.), 118 - -Ice erosion. _See_ Glacial erosion - -Incahuasi, 51, 155, 285 - -Incas, 39, 44, 46, 62, 63, 68, 77, 109, 175 - -Incharate, 78 - -Indian boatmen, 13 - -Indians, as laborers, 26-28, 31-32; - basin type, 63-64; - forest, _see_ Machigangas; - life and tastes, 107-108; - mountain, 46-67, 101-102; - plateau, 40-41, 44-45, 100, 106-109; - troops, 90, 91; - wrongs, 14, 102 - -Ingomwimbi, 206 - -Instruments, surveying, 315 - -Inter-Andean valleys, climate, 153-155 - -Intermont basin. _See_ Basins - -Intrusions, deformations north of Lambrama (diagr.), 243; - deformative effects on limestone strata near Chuquibambilla (diagr.), 221; - lower Urubamba Valley (geologic sketch map), 237; - overthrust folds in detail near Chuquibambilla (diagr.), 222; - principles, 217-219 - -Intrusions, Vilcapampa, deformative effects near Puquiura (diagr.), 216; - relation of granite to schist near Colpani (with diagr.), 216 - -Iquique, wind roses (diagrs.), 131 - -Irrigation, 72, 76, 80, 82; - coastal belt (map), 113; - coastal desert, 119-120; - Ica Valley (diagr.), 118 - -Islay, Pampa de, 114 - -Italians, 18, 81 - - -Jaguey, 254, 255, 318 - -Jesuits, 68 - -Johnson, W. D., 213, 295, 296, 299, 300 - - -Kenia, Mt., 206, 274 - -Kerbey, Major, 8, 10 - -Kibo, 206, 274 - -Kilimandjaro, 205, 206 - -Kinibalu, 206 - -Krüger, Herr, 157 - - -Labor, 26-28, 31-32, 42-43, 74-75, 83-84 - -La Cumbre Quadrangle, 197, 202, opp. p. 202 (topog. sheet) - -La Joya, 132, 133; - cloudiness (diagr.), 134; - temperature curves (diagr.), 134; - wind roses (diagrs.), 135 - -Lambrama, 90, 92, 285, 316; - camp near (ill.), opp. p. 6 - -Lambrama Quadrangle (topog. sheet), opp. p. 304 - -Lambrama Valley, deformation types (diagr.), 243 - -Land and sea, Carboniferous hypothetical distribution - compared with present (diagr.), 246 - -Landscape, 183-198 - -Lanius, P. B., 13 - -La Paz, 93, 109, 276, 321 - -La Sama, 12, 13, 40 - -Las Lomas, 318 - -Lava flows, 199 - -Lava plateau, 197, 199, 307-308; - regional diagram of physical conditions, 55; - summit above Cotahuasi (ill.), opp, p. 204 - -Lavas, volume, 201 - -Lima, 92, 93, 118, 137, 138; - cloud, 132, 143; - temperature, 126 - -Limestone, sketch to show deformed, 243 - -Little, J. P., 135, 157 - -Llica, 275 - -Lower Cretaceous fossils, 323 - -Lower Devonian fossils, 321 - - -Machigangas, 10, 11, 12, 14, 18, 19, 31, 36-45, 81; - ornaments and fabrics (ill.), opp. p. 27; - trading with (ill.), opp. p. 26 - -Machu Picchu, 72, 220; - weather data (with diagr.), 158-160 - -Madeira-Mamoré railroad, 33 - -Madre de Dios, 1, 2, 33 - -Majes River, 147, 225, 227, 266, 267; - Canyon (ill.), opp. p. 230 - -Majes Valley, 106, 111, 116, 117, 120, 226, 227, 229-231, 318; - alluvial fill, 273; - date of formation, 258, 261; - desert coast (ill.), opp. p. 110; - dunes, 262-267; - erosion and uplift, 261; - lower and upper sandstones (ill.), opp. p. 250; - sediments, 255; - snowline, 283; - steep walls and alluvial fill (ill.), opp. p. 230; - structural details near Aplao (sketch section), 255; - structural details on south wall near Cantas (sketch section), 257; - structural relations at Aplao (field sketch), 256; - Tertiary deposits, 253-254; - wind, 130; - view below Cantas (ill.), opp. p. 110; - view down canyon (ill.), opp. p. 144 - -Malaria, 14, 38 - -Marañon, 41, 59 - -Marcoy, 79 - -Marine terrace at Mollendo (ill.), opp. p. 226 - -Maritime Cordillera, 52, 199-203, 233; - asymmetry of ridges, 308-309; - glacial features, 307; - glacial topography north of divide on 73d meridian (ill.), opp. p. 281; - pre-volcanic topography, 200; - post-glacial volcano, asymmetrical (diagr.), 306; - regional diagrams, 50, 52; - test of explanation of cirques, 303; - volcanoes, tuffs, lava flows (ill.), opp. p. 204; - western border rocks (geologic section), 257; - _see also_ Lava plateau - -Matara, 99, 316 - -Matthes, F. E., 286, 287, 289 - -Mature slopes, 185-193; between Ollantaytambo and Urubamba - (ill.), opp. p. 185; - dissected, north of Anta (ill.), opp. p. 185 - -Mawenzi, 206 - -Meanders, 16, 17 - -Médanos, 114 - -Mendoza, Padre, 11 - -Mer de Glace, 203 - -Meteorological records, 157-181 - -Mexican revolutions, 93 - -Middendorf, 143 - -Miller, General, 41, 78, 147 - -Minchin, 241 - -Misti, El, opp. p. 7 (ill.), 284 - -Molina, Christoval de, 175 - -Mollendo, 93, 105, 117; - cloud belt, 143; - cloudiness (diagr.), 134; - coastal terraces, 225; - humidity, 133; - marine terrace (ill.), opp. p. 226; - profile of coastal terraces (diagr.), 227; - temperature curves (diagr.), 134; - wind roses (diagrs.), 129 - -Mollendo-Arequipa railroad, 117 - -Mollendo rubber, 32 - -Montaña, 148, 149, 153 - -Moquegua, 117; - geologic relations (diagr.), 255 - -Moraines, 207, 210-211; - Choquetira Valley (ill.), opp. p. 208; - view (ill.), opp. p. 208 - -Morales, Señor, 11 - -Morococha, temperature (diagrs. of ranges), insert opp. p. 172; - weather data (with diagrs.), 171-176 - -Morococha Mining Co., 157, 171 - -Morro de Arica, 132 - -Moss, large ground. _See Yareta_ - -Moss-draped trees (ill.), opp. p. 24 - -Mountain-side trail (ill.), opp. p. 78 - -Mountains, tropical, as climate registers, 206 - -Mulanquiato, 10, 18, 19 - -Mule trail (ill.), opp. p. 18 - -Mules, 23, 24, 94, opp. p. 91 (ill.) - - -Névé, 286-305 - -Niño, El, 137-138 - -Nivation, 285-294; - "pocked" surface (ill.), opp. p. 286 - -Northeastern border, topographic and structural section (diagr.), 241 - - -Occobamba Valley, 79 - -Ocean currents of adjacent waters, 121-122 (map), 123 - -Ollantaytambo, 70, 73, 75, 250, 271; - terraced valley floor (ill.), opp. p. 56 - -d'Orbigny, 322 - -Oruro, 93 - - -Pabellon, 80, 82, opp. p. 150 - -Pacasmayo, Carboniferous land plants, 245 - -Pachitea, 37, 38 - -Pacific Ocean basin, 248 - -Paleozoic strata (ill.), opp. p. 198 - -_Palma carmona_, 29 - -Palmer, H. S., 250 - -Paltaybamba, opp. p. 74 - -Pampacolca, 109 - -Pampaconas, 69, 211, 213, 215; - rounded slopes near Vilcabamba (ill.), opp. p. 72; - Carboniferous, 244; - fossils, 322; - snow action, 291 - -Pampaconas River, 316 - -Pampas, 114, 198; - climate data, 134-136 - -Pampas, river, 189 - -Panta, mt., 214; - view, with glacier system (ill.), opp. p. 287 - -Pará rubber, 32 - -Pasaje, 51, 57, 59, 60, 236, 238, 240, 241, 243; - Carboniferous, 244; - crossing the Apurimac (ills.), opp. p. 91 - -Paschinger, 274 - -Pastures, 141, 187; - Alpine (ill.), opp. p. 58 - -Paucartambo, 42, 77 - -Paucartambo River. _See_ Yavero River - -Payta, 225 - -Penck, A., 205 - -Peonage, 25, 27, 28 - -Pereira, Señor, 10, 18 - -Perene, 155 - -Physiographic and geologic development, 233-273 - -Physiographic evidence, value, 193-195 - -Physiographic principles, 217 - -Physiography, 183-186; - Southern Peru, summary, 197-198 - -Pichu-Pichu, 284 - -Piedmont accumulations, 260 - -Pilcopata, 36 - -Piñi-piñi, 36 - -Pisco, 130; - Carboniferous land plants, 247 - -Piura, 119 - -Piura River, depth diagram, 119, 120 - -Piura Valley, 48 - -Place names, key to, 324 - -Plantations, 86; - _see also_ Haciendas - -Planter, coastal, 6 - -Planters, valley, 3, 75, 76 - -Plateau Indians, 40-41, 44-45, 100, 106-109 - -Plateaus, 196-197 - -Pleistocene deposits, 267-273 - -Pomareni, 19 - -Pongo de Mainique, 8, 9, 11, 15-20, 40, 71, 179, 239, 241, 242, 273; - canoe in rapid above (ill.), opp. p. 11; - Carboniferous, 244; - dugout in rapids below (ill.), opp. p. 2; - fossils, 322; - temperature curve (diagr.), 178; - upper entrance (ill.), opp. p. 10; - vegetation, clearing, and rubber station (ill.), opp. p. 2 - -Poopó, 195 - -Potato field (ill.), opp p. 67 - -Potatoes, 57, 59, 62 - -Potosí, 249 - -Precipitation. _See_ Rain - -Profiles, composition of slopes and profiles (diagr.), 191 - -Pucamoco, 78 - -Pucapacures, 42 - -Puerto Mainique, 29, 30 - -Punas, 6, 197 - -Puquiura, 67, 87, 211, 216, 236, 238, 239, 243, 277; - Carboniferous, 244; - composition of slopes (ill.), opp. p. 198 - -Puqura, 250 - - -Quebradas, 145, 155 - -Quechuas, 44, 45, 77, 83 - -_Quenigo_, 285 - -Quilca, 105, 117, 226, 266 - -Quillabamba, opp. p. 74 - -Quillagua, 260 - - -Railroads, 74, 75, 76, 93, 101-102, 149; - Bolivia, 93; - Cuzco to Santa Ana, 69-70 - -Raimondi, 77, 78, 109, 110, 135, 155, 170, 316 - -Rain, 115, 119, 120, 122, 124-125; - coast region seasonal variation, 131-137; - eastern border of Andes, belts (diagrs.), 148; - effect of heavy, 138-140; - effect of sea-breeze, 131-132; - heaviest, 147-148; - Morococha (with diagrs.), 173-176; - periodic variations, 137; - Santa Lucia (with diagrs.), 164-166; - unequal distribution in western Peru, 145-147 - -Regional diagrams, 50; - index map, 23; - note on, 51 - -Regions of Peru, 1, 7 - -Reiss, 205, 208 - -Revolutions, geographic basis, 88-109 - -Rhone glacier, 205 - -Rice, 76 - -Robledo, L. M., 9, 30, opp. p. 78 - -Rock belts, outline sketch along 73d meridian, 235 - -Rocks, Maritime Cordillera, pampas and Coast Range structural - relations (sketch section), 254; - Maritime Cordillera, western border (geologic section), 257; - Moquegua, structural relations (diagr.), 255; - Urubamba Valley, succession (diagr.), 249 - -Rosalina, 8, 9, 10, 11, 37, 42, 71, 73, 80, 82, 153, 237 - -Rubber, 18; - price, 32, 33 - -Rubber forests, 22-35 - -Rubber gatherers, Italian, 18, 81 - -Rubber plant (ill.), opp. p. 75 - -Rubber trees, 152 - -Rueda, José, 78 - -Rug weaver (ill.), opp. p. 68 - -Rumbold, W. R., 321 - -Russell, I. C., 205 - -Ruwenzori, 206, 274 - - -Sacramento, Pampa del, 37 - -Sahuayaco, 77, 78, 80, 83, 179; - forests (ills.), opp. p. 90; - temperature curve (diagr.), 178 - -Salamanca, 54, 56, 105, 106, 180, 181; - forest, 285; - temperature curve (diagr.), 180; - terraced hill slopes (ill.), opp. p. 58; - view (ill.), opp. p. 107 - -Salaverry, 119 - -Salcantay, 64, 72, opp. p. 3 (ill.) - -San Geronimo, 276 - -Sand. _See_ Dunes - -"Sandy matico" (ill.), opp. p. 90 - -San Gabriel, Hacienda, 316 - -Santa Ana, 69, 72, 78, 79, 80, 82, 93, 153, 179, 237; - clouds (ill.), opp. p. 180; - temperature curve (diagr.), 178 - -Santa Ana Valley, 10, 82 - -Santa Lucia, temperature ranges (diagrs.), insert opp. p. 162; - unusual weather conditions, 169-170; - weather data (with diagrs.), 161-171 - -Santo Anato, 40, 42, 82, 179; - temperature curve (diagr.), 178 - -Schists and Silurian slates, 236-241 - -Schrund. _See_ Bergschrunds - -Schrundline, 300-305 - -Schuchert, Chas., 321 - -Sea and land. _See_ Land and sea - -Sea-breeze, 129-132 - -Shepherd, highland, 4 - -Shepherds, country of, 46-67 - -Shirineiri, 36, 38 - -Sierra Nevada, 305 - -Sierra Nevada de Santa Marta, 205 - -Sievers, W., 143, 176, 205, 263 - -Sihuas, Pampa de, 114, 198 - -Sillilica, Cordillera, 190, 260 - -Sillilica Pass, 275 - -Silurian fossils, 321 - -Silurian slates, 236-241 - -Sintulini rapids, 19 - -Sirialo, 8, 15 - -Slave raiders, 14 - -Slavery, 24, 25 - -Slopes, composition at Puquiura (ill.), opp. p. 198; - composition of slopes and profiles (diagr.), 191; - smooth grassy (ill.), opp. p. 79; - _see also_ Mature slopes - -Smallpox, 14, 38 - -Snow, 212; - drifting, 278; - fields on summit of Cordillera Vilcapampa (ill.), opp. p. 268 - -Snow erosion. _See_ Nivation - -Snow motion, curve of (diagr.), 293; - law of variation, 291 - -Snowline, 52, 53, 66, 122, 148, 203, 205-206, 274-285; - canting (with diagr.), 279; - determination, 282; - difference in degree of canting (diagr.), 281; - glacial period, 282; - view of canted, Cordillera Vilcapampa (ill.), opp. p. 280 - -Snowstorm, 170 - -Soiroccocha, 64, 72, 214; - view (ill.), opp. p. 154 - -Solimana, 4, 202, 317; - glaciation, 307 - -Soray, 64 - -Sotospampa, 243 - -South Pacific Ocean, 125 - -Spanish Conquest, 62, 63, 77 - -Spruce (botanist), 153 - -Steinmann, 249, 276 - -Streams, Coast Range, 145-147; - physiography, 192; - _see also_ Water - -Structure. _See_ Rocks - -Stübel, 209 - -Sucre, 93 - -Sugar, 73, 74, 75, 76, 82-83, 92 - -Sullana, 119 - -Survey methods employed in topographic sheets, 315 - - -Tablazo de Ica, 198 - -Tarai. _See_ Urubamba Valley - -Tarapacá, Desert of, 260 - -Tarapoto, 153 - -Taurisma, 317; - geologic sketch map and cross-section, 248 - -Taylor, Capt. A., 126, 128 - -Temperature, Abancay curve (diagr.), opp. p. 180; - Callao (with diagr.), 126-129; - Cochabamba, 176-178; - Cochabamba (diagrs. of ranges), insert opp. p. 178; - curves at various points along 73d meridian, 178-181; - La Joya curves (diagr.), 134; - Mollendo curves (diagr.), 134; - Morococha, 171-173; - Morococha (diagrs. of ranges), insert opp. p. 172; - progressive lowering of saturation, in a desert (diagr.), 127; - Santa Lucia, 161-164; - Santa Lucia (diagrs. of ranges), insert opp. p. 162 - -Tempests, 169-170 - -Terraces, coastal, 225-232; - physical history and physiographic development (with diagrs.), 228-230; - profile at Mollendo (diagr.), 227 - -Terraces, hill slopes (ill.), opp. p. 58 - -Terraces, marine (ill.), opp. p. 226 - -Terraces, valley (ills.), opp. p. 56, opp. p. 57, opp. p. 66; - Huaynacotas (ill.), opp. p. 199 - -_Terral_, 130 - -Tertiary deposits, 249, 251-267; - coastal, 253 - -Ticumpinea, 36, 38, 251 - -Tierra blanca, 254, 266 - -Timber line, 69, 71, 79, 148 - -Timpia, 36, 38, 252; - canoe at mouth (ill.), opp. p. 19 - -Titicaca, 161, 176, 195, 321 - -Titicaca basin, 107 - -Titicaca-Poopó basin, 251 - -Tocate. _See_ Abra Tocate - -_Tola_ bush (ill.), opp. p. 6 - -Tono, 36 - -Topographic and climatic cross-section (diagr.), opp. p. 144 - -Topographic and structural section of northeastern border - of Andes (diagr.), 241 - -Topographic map of the Andes between Abancay and the Pacific - Coast at Camaná, insert opp. p. 312 - -Topographic profiles across typical valleys (diagrs.), 189 - -Topographic regions, 121-122; - map, 123 - -Topographic sheets, survey method employed, 315; - list of, with page references, xi - -Topographical outfit, 315 - -Torontoy, 10, 70, 71, 72, 82, 158, 220 - -Torontoy Canyon, 272, opp. p. 3 (ill.); - cliff (ill.), opp. p. 10 - -Trail (mountain-side) (ill.), opp. p. 78 - -Transportation, 73-74, 93, 152; - rains and, 142 - -Trees, 150; - _see also_ Forests - -_Tucapelle_ (ship), 117 - -Tucker, H. L., ix - -Tumbez, 119 - -Tunari peaks, 276 - - -Ucayali, 42, 44 - -Uplift, recent, 190 - -Upper Carboniferous fossils, 322 - -Urubamba, 1, 41, 42, 62, 187; - village, 70, 73 - -Urubamba River, 72; - fossils, 322; - physiographic observations, 252-253; - rapids and canyons, 8-21; - shelter hut (ill.), opp. p. 11 - -Urubamba Valley, 72, 153, 238; - alluvial fans, 270; - alluvial fill, 272-273; - below Paltaybamba (ill.), opp. p. 74; - canyon walls (ill.), opp. p. 218; - dissected alluvial fans (sketch), 271; - floor from Tarai (ill.), opp. p. 70; - from ice to sugar cane (ill.), opp. p. 3; - geologic sketch map of the lower, 237; - line of unconformity of geologic structure (ill.), opp. p. 250; - rocks, 250; - rocks, succession (diagr.), 249; - sketch map, 9; - slopes and alluvial deposits between Ollantaytambo and Torontoy - (ill.), opp. p. 269; - temperature curves (diagrs.), 178-179; - terraced valley slopes and floor (ill.), opp. p. 66; - vegetation, distribution (ill.), opp. p. 79; - view below Santa Ana (ill.), opp. p. 155; - wheat and bread, 71 - - -Valdivia, Señor, 161 - -Vallenar, 49 - -Valley climates in canyoned region (diagr.), 59 - -Valley planters. _See_ Planters - -Valley profiles, abnormal, 305-313 - -Valleys, eastern; - _see_ Border valleys of the Eastern Andes; - _see also_ Dry valleys, Inter-Andean valleys; - topographic profiles across, typical in Southern Peru (diagrs.), 189 - -Vegetation, 141; - belts (map), 123; - distribution in Urubamba Valley (ill.), opp. p. 79; - shrubbery, mixed with grass (ill.), opp. p. 154; - Tocate pass (ill.), opp. p. 19; - _see also_ Forests - -Vicuña, 54 - -Vilcabamba, 66; - rounded slopes (ill.), opp. p. 72 - -Vilcabamba pueblo, 211, 277, 296 - -Vilcabamba Valley, 189 - -Vilcanota knot, 276 - -Vilcanota Valley, alluvial fill, 272 - -Vilcapampa, Cordillera, 15, 16, 22, 51, 53, 64, 66, 67, 197, 204-224, 233; - batholith and topographic effects, 215-224; - canted snowline (ill.), opp. p. 280; - climatic barrier, 73; - composite geologic section (diagr.), 215; - glacial features, 204-214; - glaciers, 304; - highest pass, crossing (ill.), opp. p. 7; - regional diagram, 65; - regional diagram of the eastern aspect, 68; - schrundline, 302; - snow movement, 287-289; - snow fields on summit (ill.), opp. p. 268; - snow peaks (ill.), opp. p. 72; - snowline, 277, 279; - southwestern aspect (ill.), opp. p. 205; - summit view (ill.), opp. p. 205 - -Vilcapampa Province, 77 - -Vilcapampa Valley, bowldery fill, 269 - -Vilque, 176 - -Violle, 309 - -_Virazon_, 130 - -Vitor, Pampa de, 114, 318 - -Vitor River, 92, 117, 226, 266, 267 - -Volcanic country, 199 - -Volcanic flows, geologic sketch, 244 - -Volcanoes, glacial erosion, 311; - post-glacial, 306-307; - recessed southern slopes (ill.), opp. p. 287; - snowline, 281; - typical form, 310; - views (ills.), opp. p. 204 - -Von Boeck, 176 - -Vulcanism, 199; - _see also_ Volcanoes - - -Ward, R. De C., 126, 143 - -Water, 59, 60, 116, 139; - projected canal from Atlantic to Pacific slope of the - Maritime Cordillera (diagr.), 118; - streams of coastal desert, intermittent and perennial, - diagrams of depth, 119 - -Water skippers, 17 - -Watkins, Mr., 317, 318 - -Weather. _See_ Meteorological records - -Western Andes, 199-203 - -Whymper, 205 - -Wind belts, 122; - map, 123 - -Wind roses, Callao (diagrs.), 128; - Caraveli (diagrs.), 136; - Iquique (diagrs.), 131; - La Joya (diagrs.), 135; - Machu Picchu (diagrs.), 159; - Mollendo (diagrs.), 129; - Santa Lucia (diagrs.), 167; - summer and winter of 1911-1913 (diagrs.), 130 - -Winds, 114, 116; - directions at Machu Picchu, 158-159; - geologic action, 262-267; - prevailing, 125; - Santa Lucia (with diagrs.), 166-168; - trade, 122, 124; - sea-breeze, 129-132 - -Wine, 116, 117 - -Wolf, 205 - - -Yanahuara pass, 170 - -Yanatili, 41, 42, 44; - slopes at junction with Urubamba River (ill.), opp. p. 79 - -_Yareta_ (ill.), opp. p. 6 - -Yavero, 30, 31, 36, 38, 42, 179; - temperature curve (diagr.), 178 - -Yavero (Paucartambo) River, rubber station (ill.), opp. p. 24 - -Yuca, growing (ill.), opp. p. 75 - -Yunguyo, 176 - -Yuyato, 36, 38 - - * * * * * - -FOOTNOTES: - -[1] For all locations mentioned see maps accompanying the text or -Appendix C. - -[2] The Cashibos of the Pachitea are the tribe for whom the Piros -besought Herndon to produce "some great and infectious disease" which -could be carried up the river and let loose amongst them (Herndon, -Exploration of the Valley of the Amazon, Washington. 1854, Vol. 1, p. -196). This would-be artfulness suggests itself as something of a match -against the cunning of the Cashibos whom rumor reports to imitate the -sounds of the forest animals with such skill as to betray into their -hands the hunters of other tribes (see von Tschudi, Travels in Peru -During the Years 1838-1842, translated from the German by Thomasina -Ross, New York, 1849, p. 404). - -[3] The early chronicles contain several references to Antisuyu and the -Antis. Garcilaso de la Vega's description of the Inca conquests in -Antisuyu are well known (Royal Commentaries of the Yncas, Book 4, -Chapters 16 and 17, Hakluyt Soc. Publs., 1st Ser., No. 41, 1869 and Book -7, Chapters 13 and 14, No. 45, 1871). Salcamayhua who also chronicles -these conquests relates a legend concerning the tribute payers of the -eastern valleys. On one occasion, he says, three hundred Antis came -laden with gold from Opatari. Their arrival at Cuzco was coincident with -a killing frost that ruined all the crops of the basin whence the three -hundred fortunates were ordered with their gold to the top of the high -hill of Pachatucsa (Pachatusun) and there buried with it (An Account of -the Antiquities of Peru, Hakluyt Soc. Publs., 1st Ser., No. 48, 1873). - -[4] Notice of a Journey to the Northward and also to the Northeastward -of Cuzco. Royal Geog. Soc. Journ., Vol. 6, 1836, pp. 174-186. - -[5] Walle states (Le Pérou Economique, Paris, 1907, p. 297) that the -Conibos, a tribe of the Ucayali, make annual _correrias_ or raids during -the months of July, August, and September, that is during the season of -low water. Over seven hundred canoes are said to participate and the -captives secured are sold to rubber exploiters, who, indeed, frequently -aid in the organization of the raids. - -[6] Distances are not taken from the map but from the trail. - -[7] Compare with Raimondi's description of Quiches on the left bank of -the Marañon at an elevation of 9,885 feet (3,013 m.): "the few small -springs scarcely suffice for the little patches of alfalfa and other -sowings have to depend on the precarious rains.... Every drop of water -is carefully guarded and from each spring a series of well-like basins -descending in staircase fashion make the most of the scant supply." (El -Departamento de Ancachs, Lima, 1873.) - -[8] Daily Cons. and Trade Report, June 10, 1914, No. 135, and Commerce -Reports, March 20, 1916, No. 66. - -[9] Reference to the figures in this chapter will show great variation -in the level of the timber line depending upon insolation as controlled -by slope exposure and upon moisture directly as controlled largely by -exposure to winds. In some places these controls counteract each other; -in other places they promote each other's effects. The topographic and -climatic cross-sections and regional diagrams elsewhere in this book -also emphasize the patchiness of much of the woodland and scrub, some -noteworthy examples occurring in the chapter on the Eastern Andes. Two -of the most remarkable cases are the patch of woodland at 14,500 feet -(4,420 m.) just under the hanging glacier of Soiroccocha, and the other -the quenigo scrub on the lava plateau above Chuquibamba at 13,000 feet -(3,960 m.). The strong compression of climatic zones in the Urubamba -Valley below Santa Ana brings into sharp contrast the grassy ridge -slopes facing the sun and the forested slopes that have a high -proportion of shade. Fig. 54 represents the general distribution but the -details are far more complicated. See also Figs. 53A and 53B. (See -Coropuna Quadrangle.) - -[10] Commenting on the excellence of the cacao of the montaña of the -Urubamba von Tschudi remarked (op. cit., p. 37) that the long land -transport prevented its use in Lima where the product on the market is -that imported from Guayaquil. - -[11] The inadequacy of the labor supply was a serious obstacle in the -early days as well as now. In the documents pertaining to the "Obispados -y Audiencia del Cuzco" (Vol. 11, p. 349 of the "Juicio de Limites entre -el Perú y Bolivia, Prueba Peruana presentada al Gobierno de la República -Argentina por Victor M. Maurtua," Barcelona, 1900) we find the report -that the natives of the curacy of Ollantaytambo who came down from the -hills to Huadquiña to hear mass were detained and compelled to give a -day's service on the valley plantations under pain of chastisement. - -[12] The Spanish occupation of the eastern valleys was early and -extensive. Immediately after the capture of the young Inca Tupac Amaru -and the final subjugation of the province of Vilcapampa colonists -started the cultivation of coca and cane. Development of the main -Urubamba Valley and tributary valleys proceeded at a good rate: so also -did their troubles. Baltasar de Ocampo writing in 1610 (Account of the -Province of Vilcapampa, Hakluyt Soc. Publs., Ser. 2, Vol. 22, 1907, pp. -203-247) relates the occurrence of a general uprising of the negroes -employed on the sugar plantations of the region. But the peace and -prosperity of every place on the eastern frontier was unstable and quite -generally the later eighteenth and earlier nineteenth centuries saw a -retreat of the border of civilization. The native rebellion of the -mid-eighteenth century in the montaña of Chanchamayo caused entire -abandonment of a previously flourishing area. When Raimondi wrote in -1885 (La Montaña de Chanchamayo, Lima, 1885) some of the ancient -hacienda sites were still occupied by savages. In the Paucartambo -valleys, settlement began by the end of the sixteenth century and at the -beginning of the nineteenth before their complete desolation by the -savages they were highly prosperous. Paucartambo town, itself, once -important for its commerce in coca is now in a sadly decadent condition. - -[13] Notice of a Journey to the Northward and also to the Eastward of -Cuzco, and among the Chunchos Indians, in July, 1835. Journ. Royal Geog. -Soc., Vol. 6, 1836, pp. 174-186. - -[14] Bol. Soc. Geog. de Lima, Vol. 8, 1898, p. 45. - -[15] Marcoy who traveled in Peru in the middle of the last century was -greatly impressed by the sympathetic changes of aspect and topography -and vegetation in the eastern valleys. He thus describes a sudden change -of scene in the Occobamba valley: "... the trees had disappeared, the -birds had taken wing, and great sandy spaces, covered with the latest -deposits of the river, alternated with stretches of yellow grass and -masses of rock half-buried in the ground." (Travels in South America, -translated by Elihu Rich, 2 vols. New York, 1875, Vol. 1, p. 326.) - -[16] According to the latest information (August, 1916) of the Bolivia -Railway Co., trains are running from Oruro to Buen Retiro, 35 km. from -Cochabamba. Thence connection with Cochabamba is made by a tram-line -operated by the Electric Light and Power Co. of that city. The Bulletin -of the Pan-American Union for July, 1916, also reports the proposed -introduction of an automobile service for conveyance of freight and -passengers. - -[17] During his travels Raimondi collected many instances of the -isolation and conservatism of the plateau Indian: thus there is the -village of Pampacolca near Coropuna, whose inhabitants until recently -carried their idols of clay to the slopes of the great white mountain -and worshiped them there with the ritual of Inca days (El Perú, Lima, -1874, Vol. 1). - -[18] Raimondi (op. cit., p. 109) has a characteristic description of the -"Camino del Peñon" in the department of La Libertad: "... the ground -seems to disappear from one's feet; one is standing on an elevated -balcony looking down more than 6,000 feet to the valley ... the road -which descends the steep scarp is a masterpiece." - -[19] Figs. 67 and 68 are from Bol. de Minas del Perú, 1906, No. 37, pp. -82 and 84 respectively. - -[20] The Boletín de Minas del Peru, No. 34, 1905, contains a graphic -representation of the régime of the Rio Chili at Arequipa for the years -1901-1905. - -[21] Hann (Handbook of Climatology, translated by R. De C. Ward, New -York, 1903) indicates a contributory cause in the upwelling of cold -water along the coast caused by the steady westerly drift of the -equatorial current. - -[22] This is the elevation obtained by the Peruvian Expedition. -Raimondi's figure (1,832 m.) is higher. - -[23] According to Ward's observations the base of the cloud belt -averages between 2,000 and 3,000 feet above sea level (Climatic Notes -Made During a Voyage Around South America, Journ. of School Geogr., Vol. -2, 1898). On the south Peruvian coast, specifically at Mollendo, -Middendorf found the cloud belt beginning about 1,000 feet and extending -upwards to elevations of 3,000 to 4,000 feet. At Lima the clouds descend -to lower levels (El Clima de Lima, Bol. Soc. Geogr. de Lima, Vol. 15, -1904). In the third edition of his Süd und Mittelamerika (Leipzig and -Vienna, 1914) Sievers says that at Lima in the winter the cloud on the -coast does not exceed an elevation of 450 m. (1,500 feet) while on the -hills it lies at elevations between 300 and 700 m. (1,000 and 2,300 -feet). - -[24] In most of the coast towns the ford or ferry is an important -institution and the _chimbadores_ or _baleadores_ as they are called are -expert at their trade: they know the régime of the rivers to a nicety. -Several settlements owe their origin to the exigencies of -transportation, permanent and periodic; thus before the development of -its irrigation system Camaná, according to General Miller (Memoirs, -London, 1829, Vol. 2, p. 27), was a hamlet of some 30 people who gained -their livelihood through ferrying freight and passengers across the -Majes River. - -[25] A dry pocket in the Huallaga basin between 6° and 7° S. is -described by Spruce (Notes of a Botanist on the Amazon and Andes, 2 -vols., London, 1908). Tarapoto at an elevation of 1,500 feet above sea -level, encircled by hills rising 2,000 to 3,000 feet higher, rarely -experiences heavy rain though rain falls frequently on the hills. - -[26] Speaking of Cómas situated at the headwaters of a source of the -Perene amidst a multitude of _quebradas_ Raimondi (op. cit., p. 109) -says it "might properly be called the town of the clouds, for there is -not a day during the year, at any rate towards the evening, when the -town is not enveloped in a mist sufficient to hide everything from -view." - -[27] Observer: E. C. Erdis of the 1912 and 1914-15 Expeditions. - -[28] Percentages given because the number of observations varies. - -[29] Observer: Señor Valdivia. For location of Santa Lucia see Fig. 66. - -[30] Observations began on May 12. - -[31] For the first half of the month only; no record for the second -half. - -[32] Boletín de la Sociedad Geográfica de Lima, Vol. 13, pp. 473-480, -Lima, 1903. - -[33] Boletín del Cuerpo de Ingenieros de Minas del Perú, No. 34, Lima, -1905, also reproduced in No. 45, 1906. - -[34] The record is copied literally without regard to the absurdity of -the second and third decimal places. - -[35] In the Eastern Cordillera, however, snowstorms may be more serious. -Prior to the construction of the Urubamba Valley Road by the Peruvian -government the three main routes to the Santa Ana portion of the valley -proceeded via the passes of Salcantay, Panticalla, and Yanahuara -respectively. Frequently all are completely snow-blocked and fatalities -are by no means unknown. In 1864 for instance nine persons succumbed on -the Yanahuara pass (Raimondi, op. cit., p. 109). - -[36] Boletín de la Sociedad Geográfica de Lima, Vol. 27, 1911; Vol. 28, -1912. - -[37] Boletín del Cuerpo de Ingenieros de Minas del Perú, No. 65, 1908. - -[38] This figure is approximate: some days' records were missing from -the first three months of the year and the total was estimated on a -proportional basis. - -[39] Christoval de Molina, The Fables and Rites of the Yncas, Hakluyt -Soc. Publs., 1st Ser., No. 48, 1873. - -[40] See Meteorologische Zeitschrift, Vol. 5, p. 195, 1888. Also cited -by J. Hann in Handbuch der Climatologie, Vol. 2, Stuttgart, 1897; W. -Sievers, Süd und Mittelamerika, Leipzig and Vienna, 1914, p. 334. - -[41] The Physiography of the Central Andes, Am. Journ. Sci., Vol. 40, -1909, pp. 197-217 and 373-402. - -[42] Results of an Expedition to the Central Andes, Bull. Am. Geog. -Soc., Vol. 46, 1914. Figs. 28 and 29. - -[43] The Physiography of the Central Andes, by Isaiah Bowman; Am. Journ. -Sci., Vol. 28, 1909, pp. 197-217 and 373-402. See especially, _ibid._, -Fig. 11, p. 216. - -[44] Travels Amongst the Great Andes of the Equator, 1892. - -[45] Geografía y Geología del Ecuador, 1892. - -[46] Das Hochgebirge der Republik Ecuador, Vol. 2, 2 Ost-Cordillera, -1902, p. 162. - -[47] Contributions to the Geology of British East Africa; Pt. 1, The -Glacial Geology of Mount Kenia, Quart. Journ. Geol. Soc., Vol. 50, 1894, -p. 523. - -[48] See especially A. Penck (Penck and Brückner), Die Alpen im -Eiszeitalter, 1909, Vol. 1, p. 6, and I. C. Russell, Glaciers of Mount -Rainier, 18th Ann. Rep't, U. S. Geol. Surv., 1890-97, Sect. 2, pp. -384-385. - -[49] Die Sierra Nevada de Santa Marta und die Sierra de Perijá, -Zeitschrift der Gesellschaft für Erdkunde zu Berlin, Vol. 23, 1888, pp. -1-158. - -[50] For a list of the fossils that form the basis of the age -determinations in this chapter see Appendix B. - -[51] Eastern Bolivia and the Gran Chaco, Proc. Royal Geogr. Soc., Vol. -3, 1881, pp. 401-420. - -[52] The Physiography of the Central Andes, Am. Journ. Sci., Vol. 28, -1909, p. 395. - -[53] See paper by H. S. Palmer, my assistant on the Expedition to the -Central Andes, 1913, entitled: Geological Notes on the Andes of -Northwestern Argentina, Am. Journ. Sci., Vol. 38, 1914, pp. 309-330. - -[54] The best photograph of this condition which I have yet seen is in -W. Sievers, Südund Mittelamerika, second ed., 1914, Plate 15, p. 358. - -[55] Paschinger, Die Schneegrenze in verschiedenen Klimaten. Peter. -Mitt. Erganz'heft, Nr. 173. 1912, pp. 92-93. - -[56] Hann, Handbook of Climatology, Part 1, trans. by Ward, 1903, p. -232. - -[57] S. I. Bailey, Peruvian Meteorology, 1888-1890. Ann. Astron. Observ. -of Harvard Coll., Vol. 39, Pt. I, 1899, pp. 1-3. - -[58] F. E. Matthes, Glacial Sculpture of the Bighorn Mountains, Wyoming, -Twentieth Ann. Rept. U. S. Geol. Surv., 1899-1900, Pt. 2, p. 181. - -[59] Idem, p. 190. - -[60] W. H. Hobbs, Characteristics of Existing Glaciers, 1911, p. 22. - -[61] Op. cit., p. 286. Reference on p. 190. - -[62] Corrosion of Gravity Streams with Application of the Ice Flood -Hypothesis, Journ. and Proc. of the Royal Society of N. S. Wales, Vol. -43, 1909, p. 286. - -[63] G. K. Gilbert, Systematic Asymmetry of Crest Lines in the High -Sierra of California. Jour. Geol., Vol. 12, 1904, p. 582. - -[64] Op. cit., p. 300; reference on p. 582. - -[65] Op. cit., p. 300; see pp. 579-588 and Fig. 8. - -[66] The observation at Camaná checks very closely with a Peruvian -observation the value of which is S. 16° 37' 00". - - - - - - -End of Project Gutenberg's The Andes of Southern Peru, by Isaiah Bowman - -*** END OF THIS PROJECT GUTENBERG EBOOK THE ANDES OF SOUTHERN PERU *** - -***** This file should be named 42860-8.txt or 42860-8.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/4/2/8/6/42860/ - -Produced by Chuck Greif, The University of Florida Digital -Collections and the Online Distributed Proofreading Team -at http://www.pgdp.net - - -Updated editions will replace the previous one--the old editions -will be renamed. - -Creating the works from public domain print editions means that no -one owns a United States copyright in these works, so the Foundation -(and you!) can copy and distribute it in the United States without -permission and without paying copyright royalties. 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You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org/license - - -Title: The Andes of Southern Peru - Geographical Reconnaissance along the Seventy-Third Meridian - -Author: Isaiah Bowman - -Release Date: June 2, 2013 [EBook #42860] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK THE ANDES OF SOUTHERN PERU *** - - - - -Produced by Chuck Greif, The University of Florida Digital -Collections and the Online Distributed Proofreading Team -at http://www.pgdp.net - - - - - - -</pre> - -<hr class="full" /> - -<table summary="note" border="4" cellpadding="10" style="background-color: #ffffff; -margin-right:auto;margin-left:auto;max-width:60%;"> - <tr> - <td valign="top">Transcriber's note: The etext attempts to replicate the printed book as -closely as possible. Obvious errors in spelling and punctuation have -been corrected. The spellings of names, places and Spanish -words used by the author have not been corrected or modernized by the -etext transcriber. The footnotes have been moved to the end of the text body. -The images have been moved from the middle of a paragraph to the -closest paragraph break for ease of reading.</td> - </tr> -</table> - -<p class="figcenter"> -<img src="images/cover.jpg" width="372" height="550" alt="bookcover" /> -</p> - -<p class="figcenter"> -<img src="images/geologo.png" width="75" height="75" alt="" /> -</p> - -<h1>THE ANDES OF SOUTHERN<br /> -PERU</h1> - -<p class="cb">GEOGRAPHICAL RECONNAISSANCE ALONG THE<br /> -SEVENTY-THIRD MERIDIAN<br /> -<br /><br /> -BY<br /> -ISAIAH BOWMAN<br /> -<small>Director of the American Geographical Society</small><br /> -<br /><br /> -<img src="images/ill_page_title.jpg" width="80" height="103" alt="colophon" title="colophon" /> -<br /><br /> -PUBLISHED FOR<br /> -THE AMERICAN GEOGRAPHICAL SOCIETY<br /> -OF NEW YORK<br /> -BY<br /> -HENRY HOLT AND COMPANY<br /> -1916<br /><br /><br /> -<small><span class="smcap">Copyright, 1918</span><br /> -BY<br /> -HENRY HOLT AND COMPANY<br /> -<br /><br /><br /> -<small>THE QUINN & BODEN CO. PRESS<br /> -RAHWAY, N.J.</small></small> <br /><br /><br /></p> - -<p class="cb"> -TO<br /> -<br /> -C. G. B.<br /> <br /><br /> -</p> - -<h3><a name="PREFACE" id="PREFACE"></a>PREFACE</h3> - -<p>T<small>HE</small> geographic work of the Yale Peruvian Expedition of 1911 was -essentially a reconnaissance of the Peruvian Andes along the 73rd -meridian. The route led from the tropical plains of the lower Urubamba -southward over lofty snow-covered passes to the desert coast at Camaná. -The strong climatic and topographic contrasts and the varied human life -which the region contains are of geographic interest chiefly because -they present so many and such clear cases of environmental control -within short distances. Though we speak of “isolated†mountain -communities in the Andes, it is only in a relative sense. The extreme -isolation felt in some of the world’s great deserts is here unknown. It -is therefore all the more remarkable when we come upon differences of -customs and character in Peru to find them strongly developed in spite -of the small distances that separate unlike groups of people.</p> - -<p>My division of the Expedition undertook to make a contour map of the -two-hundred-mile stretch of mountain country between Abancay and the -Pacific coast, and a great deal of detailed geographic and physiographic -work had to be sacrificed to insure the completion of the survey. Camp -sites, forage, water, and, above all, strong beasts for the -topographer’s difficult and excessively lofty stations brought daily -problems that were always serious and sometimes critical. I was so -deeply interested in the progress of the topographic map that whenever -it came to a choice of plans the map and not the geography was first -considered. The effect upon my work was to distribute it with little -regard to the demands of the problems, but I cannot regret this in view -of the great value of the maps. Mr. Kai Hendriksen did splendid work in -putting through two hundred miles of plane-tabling in two months under -conditions of extreme difficulty. Many of his triangulation stations -ranged in elevation from 14,000 to nearly 18,000 feet, and the cold and -storms—especially the hailstorms of mid-afternoon—were at times most -severe.</p> - -<p>It is also a pleasure to say that Mr. Paul Baxter Lanius, my assistant -on the lower Urubamba journey, rendered an invaluable service in -securing continuous weather records at Yavero and elsewhere, and in -getting food and men to the river party at a critical time. Dr. W. G. -Erving, surgeon of the Expedition, accompanied me on a canoe journey -through the lower gorge of the Urubamba between Rosalina and the mouth -of the Timpia, and again by pack train from Santa Ana to Cotahuasi. For -a time he assisted the topographer. It is due to his prompt surgical -assistance to various members of the party that the field work was -uninterrupted. He was especially useful when two of our river Indians -from Pongo de Mainique were accidentally shot. I have since been -informed by their <i>patrón</i> that they were at work within a few months.</p> - -<p>It is difficult to express the gratitude I feel toward Professor Hiram -Bingham, Director of the Expedition, first for the executive care he -displayed in the organization of the expedition’s plans, which left the -various members largely care-free, and second, for generously supplying -the time of various assistants in the preparation of results. I have -enjoyed so many facilities for the completion of the work that at least -a year’s time has been saved thereby. Professor Bingham’s enthusiasm for -pioneer field work was in the highest degree stimulating to every member -of the party. Furthermore, it led to a determination to complete at all -hazards the original plans.</p> - -<p>Finally, I wish gratefully to acknowledge the expert assistance of Miss -Gladys M. Wrigley, of the editorial staff of the American Geographical -Society, who prepared the climatic tables, many of the miscellaneous -data related thereto, and all of the curves in Chapter X. Miss Wrigley -also assisted in the revision of Chapters IX and X and in the correction -of the proof. Her eager and in the highest degree faithful assistance in -these tasks bespeaks a true scientific spirit.</p> - -<p class="r"><span class="smcap">Isaiah Bowman.</span><br /> -</p> - -<h3>SPECIAL ACKNOWLEDGMENTS FOR ILLUSTRATIONS</h3> - -<p><a href="#fig_28">Fig. 28</a>. Photograph by H. L. Tucker, Engineer, Yale Peruvian Expedition -of 1911.</p> - -<p><a href="#fig_43">Fig. 43</a>. Photograph by H. L. Tucker.</p> - -<p><a href="#fig_44">Fig. 44</a>. Photograph by Professor Hiram Bingham.</p> - -<p>Figs. <a href="#fig_136">136</a>, <a href="#fig_139">139</a>, <a href="#fig_140">140</a>. Data for hachured sketch maps, chiefly from -topographic sheets by A. H. Bumstead, Topographer to Professor Bingham’s -Peruvian Expeditions of 1912 and 1914.</p> - -<h3><a name="CONTENTS" id="CONTENTS"></a>CONTENTS</h3> - -<table border="0" cellpadding="1" cellspacing="0" summary="" -style="margin:auto auto auto auto;max-width:80%;"> - -<tr><td align="center" colspan="3"><a href="#PART_I">PART I</a></td></tr> - -<tr><td align="center" colspan="3">HUMAN GEOGRAPHY</td></tr> - -<tr><td><small>CHAPTER</small></td><td> </td> -<td><small>PAGE</small></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_I">I.</a></td><td> <span class="smcap">The Regions of Peru</span></td><td align="right" valign="bottom"><a href="#page_001">1</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_II">II.</a></td><td> <span class="smcap">The Rapids and Canyons of the Urubamba</span></td><td align="right" valign="bottom"><a href="#page_008">8</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_III">III.</a></td><td> <span class="smcap">The Rubber Forests</span></td><td align="right" valign="bottom"><a href="#page_022">22</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_IV">IV.</a></td><td> <span class="smcap">The Forest Indians</span></td><td align="right" valign="bottom"><a href="#page_036">36</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_V">V.</a></td><td> <span class="smcap">The Country of the Shepherds</span></td><td align="right" valign="bottom"><a href="#page_046">46</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_VI">VI.</a></td><td> <span class="smcap">The Border Valleys of the Eastern Andes</span></td><td align="right" valign="bottom"><a href="#page_068">68</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_VII">VII.</a></td><td> <span class="smcap">The Geographic Basis of Revolutions and of Human -Character in the Peruvian Andes</span></td><td align="right" valign="bottom"><a href="#page_088">88</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_VIII">VIII.</a></td><td> <span class="smcap">The Coastal Desert</span></td><td align="right" valign="bottom"><a href="#page_110">110</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_IX">IX.</a></td><td> <span class="smcap">Climatology of the Peruvian Andes</span></td><td align="right" valign="bottom"><a href="#page_121">121</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_X">X.</a></td><td> <span class="smcap">Meteorological Records From the Peruvian Andes</span></td><td align="right" valign="bottom"><a href="#page_157">157</a></td></tr> - -<tr><td align="center" colspan="3"><a href="#PART_II">PART II</a></td></tr> - -<tr><td align="center" colspan="3">PHYSIOGRAPHY OF THE PERUVIAN ANDES</td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_XI">XI.</a></td><td> <span class="smcap">The Peruvian Landscape</span></td><td align="right" valign="bottom"><a href="#page_183">183</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_XII">XII.</a></td><td> <span class="smcap">The Western Andes: the Maritime Cordillera Or Cordillera Occidental</span></td><td align="right" valign="bottom"><a href="#page_199">199</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_XIII">XIII.</a></td><td> <span class="smcap">The Eastern Andes: The Cordillera Vilcapampa</span></td><td align="right" valign="bottom"><a href="#page_204">204</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_XIV">XIV.</a></td><td> <span class="smcap">The Coastal Terraces</span></td><td align="right" valign="bottom"><a href="#page_225">225</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_XV">XV.</a></td><td> <span class="smcap">Physiographic and Geologic Development</span></td><td align="right" valign="bottom"><a href="#page_233">233</a></td></tr> - -<tr><td align="right" valign="top"><a href="#CHAPTER_XVI">XVI.</a></td><td> <span class="smcap">Glacial Features</span></td><td align="right" valign="bottom"><a href="#page_274">274</a></td></tr> -</table> - -<table border="0" cellpadding="2" cellspacing="0" summary="" -style="margin:auto auto auto auto;max-width:79%;"> - -<tr><td><span class="smcap"><a href="#APPENDIX_A">Appendix A.</a></span> <span class="smcap">Survey Methods Employed in the Construction of -the Seven Accompanying Topographic Sheets</span></td><td align="right" valign="bottom"><a href="#page_315">315</a></td></tr> - -<tr><td><span class="smcap"><a href="#APPENDIX_B">Appendix B.</a></span> <span class="smcap">Fossil Determinations</span></td><td align="right" valign="bottom"><a href="#page_321">321</a></td></tr> - -<tr><td><span class="smcap"><a href="#APPENDIX_C">Appendix C.</a></span> <span class="smcap">Key to Place Names</span></td><td align="right" valign="bottom"><a href="#page_324">324</a></td></tr> - -<tr><td><span class="smcap"><a href="#INDEX">Index</a></span></td><td align="right" valign="bottom"><a href="#page_327">327</a></td></tr> - -<tr><td align="center" colspan="3">TOPOGRAPHIC SHEETS</td></tr> - -<tr><td>Camaná Quadrangle</td><td align="right" valign="bottom"><a href="#page_114">114</a></td></tr> - -<tr><td>Aplao - "</td><td align="right" valign="bottom"><a href="#page_120">120</a></td></tr> - -<tr><td>Coropuna - - "</td><td align="right" valign="bottom"><a href="#page_188">188</a></td></tr> - -<tr><td>Cotahuasi "</td><td align="right" valign="bottom"><a href="#page_192">192</a></td></tr> - -<tr><td>La Cumbre "</td><td align="right" valign="bottom"><a href="#page_202">202</a></td></tr> - -<tr><td>Antabamba "</td><td align="right" valign="bottom"><a href="#page_282">282</a></td></tr> - -<tr><td>Lambrama - "</td><td align="right" valign="bottom"><a href="#page_304">304</a></td></tr> -</table> - -<p><a name="page_001" id="page_001"></a></p> - -<h2><a name="PART_I" id="PART_I"></a>PART I<br /><br /> -HUMAN GEOGRAPHY</h2> - -<h3><a name="CHAPTER_I" id="CHAPTER_I"></a>CHAPTER I<br /><br /> -THE REGIONS OF PERU</h3> - -<p>L<small>ET</small> four Peruvians begin this book by telling what manner of country -they live in. Their ideas are provincial and they have a fondness for -exaggerated description: but, for all that, they will reveal much that -is true because they will at least reveal themselves. Their opinions -reflect both the spirit of the toiler on the land and the outlook of the -merchant in the town in relation to geography and national problems. -Their names do not matter; let them stand for the four human regions of -Peru, for they are in many respects typical men.</p> - -<h4><span class="smcap">The Forest Dweller</span></h4> - -<p>One of them I met at a rubber station on the lower Urubamba River.<a name="FNanchor_1_1" id="FNanchor_1_1"></a><a href="#Footnote_1_1" class="fnanchor">[1]</a> He -helped secure my canoe, escorted me hospitably to his hut, set food and -drink before me, and talked of the tropical forest, the rubber business, -the Indians, the rivers, and the trails. In his opinion Peru was a land -of great forest resources. Moreover, the fertile plains along the river -margins might become the sites of rich plantations. The rivers had many -fish and his garden needed only a little cultivation to produce an -abundance of food. Fruit trees grew on every hand. He had recently -married the daughter of an Indian chief.</p> - -<p>Formerly he had been a missionary at a rubber station on the Madre de -Dios, where the life was hard and narrow, and he doubted if there were -any real converts. Himself the son of an Englishman and a Chilean woman, -he found, so he said, that a missionary’s life in the rubber forest was -intolerable for more than a few<a name="page_002" id="page_002"></a> years. Yet he had no fault to find with -the religious system of which he had once formed a part; in fact he had -still a certain curious mixed loyalty to it. Before I left he gave me a -photograph of himself and said with little pride and more sadness that -perhaps I would remember him as a man that had done some good in the -world along with much that might have been better.</p> - -<p>We shall understand our interpreter better if we know who his associates -were. He lived with a Frenchman who had spent several years in Africa as -a soldier in the “Foreign Legion.†If you do not know what that means, -you have yet all the pleasure of an interesting discovery. The Frenchman -had reached the station the year before quite destitute and clad only in -a shirt and a pair of trousers. A day’s journey north lived a young -half-breed—son of a drunken father and a Machiganga woman, who cheated -me so badly when I engaged Indian paddlers that I should almost have -preferred that he had robbed me. Yet in a sense he had my life in his -hands and I submitted. A German and a native Peruvian ran a rubber -station on a tributary two days’ journey from the first. It will be -observed that the company was mixed. They were all Peruvians, but of a -sort not found in such relative abundance elsewhere. The defeated and -the outcast, as well as the pioneer, go down eventually to the hot -forested lands where men are forgotten.</p> - -<p>While he saw gold in every square mile of his forested region, my -clerical friend saw misery also. The brutal treatment of the Indians by -the whites of the Madre de Dios country he could speak of only as a man -reviving a painful memory. The Indians at the station loved him -devotedly. There was only justice and kindness in all his dealings. -Because he had large interests to look after, he knew all the members of -the tribe, and his word was law in no hackneyed sense. A kindlier man -never lived in the rubber forest. His influence as a high-souled man of -business was vastly greater than as a missionary in this frontier -society. He could daily illustrate by practical example what he had -formerly been able only to preach.</p> - -<p><a name="fig_1" id="fig_1"></a></p> -<p><a name="fig_2" id="fig_2"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_002_lg.jpg"><br /> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -height="14" -width="18" /><br /> -<img src="images/ill_page_002_sml.jpg" width="220" height="341" alt="" /></a> -<br /> -<p class="caption"> -<span class="smcap">Fig. 1</span>—Tropical vegetation, clearing on the river bank and rubber -station at Pongo de Mainique. The pronounced scarp on the northeastern border -of the Andes is seen in the right background.</p> - -<p class="caption"> -<span class="smcap">Fig. 2</span>—Pushing a heavy dugout against the current in the rapids -below Pongo de Mainique. The indian boy and his father in the canoe had -been accidentally shot.</p> -</div> - -<p><a name="fig_3" id="fig_3"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_002a_lg.jpg"><br /> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /><br /> -<img src="images/ill_page_002a_sml.jpg" width="223" height="350" alt="From the sugar cane, Urubanba Valley, at Colpani. On the -northeastern border of the Cordillera Vilcapampa looking upstream. In the -extreme background and thirteen sixteens of an inch from the top of the picture -is the sharp peak of Salcantay. Only the lower end of the more open portion -of the Canyon of Torontoy is here shown. There is a field of sugar cane in the -foreground and the valley trail is shown on the opposite side of the river." title="" /></a> -<br /> -<p class="caption"><span class="smcap">Fig. 3</span>—From the sugar cane, Urubanba Valley, at Colpani. On the -northeastern border of the Cordillera Vilcapampa looking upstream. In the -extreme background and thirteen sixteens of an inch from the top of the picture -is the sharp peak of Salcantay. Only the lower end of the more open portion -of the Canyon of Torontoy is here shown. There is a field of sugar cane in the -foreground and the valley trail is shown on the opposite side of the river.</p> -</div> - -<p>He thought the life of the Peruvian cities debasing. The<a name="page_003" id="page_003"></a> coastal -valleys were small and dry and the men who lived there were crowded and -poor (sic). The plateau was inhabited by Indians little better than -brutes. Surely I could not think that the fine forest Indian was lower -than the so-called civilized Indian of the plateau. There was plenty of -room in the forest; and there was wealth if you knew how to get at it. -Above all you were far from the annoying officials of the government, -and therefore could do much as you pleased so long as you paid your -duties on rubber and did not wantonly kill too many Indians.</p> - -<p>For all his kindly tolerance of men and conditions he yet found fault -with the government. “They†neglected to build roads, to encourage -colonization, and to lower taxes on the forest products, which were -always won at great risk. Nature had done her part well—it was only -government that hindered. Moreover, the forested region was the land of -the future. If Peru was to be a great nation her people would have to -live largely upon the eastern plains. Though others spoke of “going in†-and “coming out†of the rubber country as one might speak of entering -and leaving a dungeon, he always spoke of it as home. Though he now -lived in the wilderness he hoped to see the day when plantations covered -the plains. A greater Peru and the forest were inseparable ideas to him.</p> - -<h4><span class="smcap">The Eastern Valley Planter</span></h4> - -<p>My second friend lived in one of the beautiful mountain valleys of the -eastern Andes. We walked through his clean cacao orchards and cane -fields. Like the man in the forest, he believed in the thorough -inefficiency of the government; otherwise why were there no railways for -the cheaper transportation of the valley products, no dams for the -generation of power and the storage of irrigation water, not even roads -for mule carts? Had the government been stable and efficient there would -now be a dense population in the eastern valleys. Revolutions were the -curse of these remote sections of the country. The ne’er-do-wells became -generals. The loafer you dismissed today might demand ten thousand -dollars tomorrow or threaten to destroy your plantation.<a name="page_004" id="page_004"></a> The government -troops might come to help you, but they were always too late.</p> - -<p>For this one paid most burdensome taxes. Lima profited thereby, not the -valley planters. The coast people were the favored of Peru anyhow. They -had railroads, good steamer service, public improvements at government -expense, and comparatively light taxes. If the government were impartial -the eastern valleys also would have railways and a dense population. Who -could tell? Perhaps the capital city might be here. Certainly it was -better to have Lima here than on the coast where the Chileans might at -any time take it again. The blessings of the valleys were both rich and -manifold. Here was neither a cold plateau nor the hot plains, but -fertile valleys with a vernal climate.</p> - -<p>We talked of much else, but our conversation had always the pioneer -flavor. And though an old man he saw always the future Peru growing -wonderfully rich and powerful as men came to recognize and use the -resources of the eastern valleys. This too was the optimism of the -pioneer. Once started on that subject he grew eloquent. He was -provincial but he was also intensely patriotic. He never missed an -opportunity to impress upon his guests that a great state would arise -when people and rulers at last recognized the wealth of eastern Peru.</p> - -<h4><span class="smcap">The Highland Shepherd</span></h4> - -<p>The people who live in the lofty highlands and mountains of Peru have -several months of real winter weather despite their tropical latitude. -In the midst of a snowstorm in the Maritime Cordillera I met a solitary -traveler bound for Cotahuasi on the floor of a deep canyon a day’s -journey toward the east. It was noon and we halted our pack trains in -the lee of a huge rock shelter to escape the bitter wind that blew down -from the snow-clad peaks of Solimana. Men who follow the same trails are -fraternal. In a moment we had food from our saddle-bags spread on the -snow under the corner of a <i>poncho</i> and had exchanged the best in each -other’s collection as naturally as friends exchange greetings. By the -time I had told him whence and why in response to his inevitable<a name="page_005" id="page_005"></a> -questions we had finished the food and had gathered a heap of <i>tola</i> -bushes for a fire. The <i>arriero</i> (muleteer) brought water from a spring -in the hollow below us. Though the snow thickened, the wind fell. We -were comfortable, even at 16,000 feet, and called the place “The -Salamanca Club.†Then I questioned him, and this is what he said:</p> - -<p>“I live in the deep valley of Cotahuasi, but my lands lie chiefly up -here on the plateau. My family has held title to this <i>puna</i> ever since -the Wars of Liberation, except for a few years after one of our early -revolutions. I travel about a great deal looking after my flocks. Only -Indians live up here. Away off yonder beyond that dark gorge is a group -of their huts, and on the bright days of summer you may see their sheep, -llamas, and alpacas up here, for on the floors of the watered valleys -that girdle these volcanoes there are more tender grasses than grow on -this <i>despoblado</i>. I give them corn and barley from my irrigated fields -in the valley; they give me wool and meat. The alpaca wool is most -valuable. It is hard to get, for the alpaca requires short grasses and -plenty of water, and you see there is only coarse tufted ichu grass -about us, and there are no streams. It is all right for llamas, but -alpacas require better forage.</p> - -<p>“No one can imagine the poverty and ignorance of these mountain -shepherds. They are filthier than beasts. I have to watch them -constantly or they would sell parts of the flocks, which do not belong -to them, or try to exchange the valuable alpaca wool for coca leaves in -distant towns. They are frequently drunk.â€</p> - -<p>“But where do they get the drink?†I asked. “And what do you pay them?â€</p> - -<p>“Oh, the drink is chiefly imported alcohol, and also <i>chicha</i> made from -corn. They insist on having it, and do better when I bring them a little -now and then. They get much more from the dealers in the towns. As for -pay, I do not pay them anything in money except when they bring meat to -the valley. Then I give them a few <i>reales</i> apiece for the sheep and a -little more for the llamas. The flocks all belong to me really, but of -course the poor Indian must have a little money. Besides, I let him have -a part<a name="page_006" id="page_006"></a> of the yearly increase. It is not much, but he has always lived -this way and I suppose that he is contented after a fashion.â€</p> - -<p>Then he became eager to tell what wealth the mountains contained in soil -and climate if only the right grasses were introduced by the government.</p> - -<p>“Here, before us, are vast <i>punas</i> almost without habitations. If the -officials would bring in hardy Siberian grasses these lava-covered -plateaus might be carpeted with pasture. There would be villages here -and there. The native Indians easily stand the altitude. This whole -Cordillera might have ten times as many people. Why does the government -bother about concessions in the rubber forests and roads to the eastern -valleys when there are these vast tracts only requiring new seeds to -develop into rich pastures? The government could thus greatly increase -its revenues because there is a heavy tax on exported wool.â€</p> - -<p>Thus he talked about the bleak Cordillera until we forgot the pounding -of our hearts and our frequent gasps for breath on account of the -altitude. His rosy picture of a well-populated highland seemed to bring -us down nearer sea level where normal folks lived. To the Indians the -altitude is nothing. It has an effect, but it is slight; at any rate -they manage to reproduce their kind at elevations that would kill a -white mother. If alcohol were abolished and better grasses introduced, -these lofty pastures might indeed support a much larger population. The -sheep pastures of the world are rapidly disappearing before the march of -the farmer. Here, well above the limit of cultivation, is a permanent -range, one of the great as well as permanent assets of Peru.</p> - -<h4><span class="smcap">The Coastal Planter</span></h4> - -<p>The man from the deep Majes Valley in the coastal desert rode out with -me through cotton fields as rich and clean as those of a Texas -plantation. He was tall, straight-limbed, and clear-eyed—one of the -energetic younger generation, yet with the blood of a proud old family. -We forded the river and rode on through vineyards and fig orchards -loaded with fruit. His manner became deeply earnest as he pictured the -future of Peru, when her people<a name="page_007" id="page_007"></a> would take advantage of scientific -methods and use labor-saving machinery. He said that the methods now in -use were medieval, and he pointed to a score of concrete illustrations. -Also, here was water running to waste, yet the desert was on either -hand. There should be dams and canals. Every drop of water was needed. -The population of the valley could be easily doubled.</p> - -<p><a name="fig_4" id="fig_4"></a></p> -<p><a name="fig_5" id="fig_5"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_006a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /> -<img src="images/ill_page_006a_sml.jpg" width="222" height="334" alt="" /></a> -<br /> -<p class="caption"><span class="smcap">Fig.</span> 4—Large ground moss--so-called <i>yareta</i>--used for -fuel. It occurs in the zone of Alpine vegetation and is best developed -in regions where the snowline is highest. The photograph represents a -typical occurrence between Cotahuasi and Salamanca, elevation 16,000 -feet (4,880 m.). The snowline is here at 17,500 feet (5,333 m.). In the -foreground is the most widely distributed <i>tola</i> bush, also used for -fuel.</p> - -<p class="caption"><span class="smcap">Fig.</span> 5.—Expedition’s camp near Lamgrama, 15,500 feet (4,720 m.), after -a snowstorm The location is midway in the pasture zone.</p> -</div> - -<p><a name="fig_6" id="fig_6"></a></p> -<p><a name="fig_7" id="fig_7"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_006b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_006b_sml.jpg" width="211" height="325" alt="Fig. 6—Irrigated Chili Valley on the outskirts of -Arequipa. The lower slopes of El Misti are in the left background. The -Alto de los Huesos or Plateau of Bones lies on the farther side of the -valley." /></a> -<br /> -<p class="caption"><span class="smcap">Fig. 6</span>—Irrigated Chili Valley on the outskirts of -Arequipa. The lower slopes of El Misti are in the left background. The -Alto de los Huesos or Plateau of Bones lies on the farther side of the -valley.</p> - -<p class="caption"><span class="smcap">Fig. 7</span>—Crossing the highest pass (Chuquito) in the -Cordillera Vilcapampa, 14,500 feet (4,420 m.). Grazing is here carried -on up to the snowline.</p> -</div> - -<p>Capital was lacking but there was also lacking energy among the people. -Slipshod methods brought them a bare living and they were too easily -contented. Their standards of life should be elevated. Education was -still for the few, and it should be universal. A new spirit of progress -was slowly developing—a more general interest in public affairs, a -desire to advance with the more progressive nations of South -America,—and when it had reached its culmination there would be no -happier land than coastal Peru, already the seat of the densest -populations and the most highly cultivated fields.</p> - -<p> </p> - -<p>These four men have portrayed the four great regions of Peru—the -lowland plains, the eastern mountain valleys, the lofty plateaus, and -the valley oases of the coast. This is not all of Peru. The mountain -basins have their own peculiar qualities and the valley heads of the -coastal zone are unlike the lower valleys and the plateau on either -hand. Yet the chief characteristics of the country are set forth with -reasonable fidelity in these individual accounts. Moreover the spirit of -the Peruvians is better shown thereby than their material resources. If -this is not Peru, it is what the Peruvians think is Peru, and to a high -degree a man’s country is what he thinks it is—at least it is little -more to him.<a name="page_008" id="page_008"></a></p> - -<h3><a name="CHAPTER_II" id="CHAPTER_II"></a>CHAPTER II<br /><br /> -THE RAPIDS AND CANYONS OF THE URUBAMBA</h3> - -<p>A<small>MONG</small> the scientifically unexplored regions of Peru there is no other so -alluring to the geographer as the vast forested realm on the eastern -border of the Andes. Thus it happened that within two weeks of our -arrival at Cuzco we followed the northern trail to the great canyon of -the Urubamba (<a href="#fig_8">Fig. 8</a>), the gateway to the eastern valleys and the -lowland plains of the Amazon. It is here that the adventurous river, -reënforced by hundreds of mountain-born tributaries, finally cuts its -defiant way through the last of its great topographic barriers. More -than seventy rapids interrupt its course; one of them, at the mouth of -the Sirialo, is at least a half-mile in length, and long before one -reaches its head he hears its roaring from beyond the forest-clad -mountain spurs.</p> - -<p>The great bend of the Urubamba in which the line of rapids occurs is one -of the most curious hydrographic features in Peru. The river suddenly -changes its general northward course and striking south of west flows -nearly fifty miles toward the axis of the mountains, where, turning -almost in a complete circle, it makes a final assault upon the eastern -mountain ranges. Fifty miles farther on it breaks through the long -sharp-crested chain of the Front Range of the Andes in a splendid gorge -more than a half-mile deep, the famous <i>Pongo de Mainique</i> (<a href="#fig_9">Fig. 9</a>).</p> - -<p>Our chief object in descending the line of rapids was to study the -canyon of the Urubamba below Rosalina and to make a topographic sketch -map of it. We also wished to know what secrets might be gathered in this -hitherto unexplored stretch of country, what people dwelt along its -banks, and if the vague tales of deserted towns and fugitive tribes had -any basis in fact.</p> - -<p><a name="fig_8" id="fig_8"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_009_lg.jpg"><br /> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /> -<img src="images/ill_page_009_sml.jpg" width="219" height="247" alt="Fig. 8—Sketch map showing the route of the Yale-Peruvian -Expedition of 1911 down the Urubamba Valley, together with the area of -the main map and the changes in the delineation of the bend of the -Urubamba resulting from the surveys of the Expedition. Based on the -“Mapa que comprende las ultimas exploraciones y estudios verificados -desde 1900 hasta 1906,†1:1,000,000, Bol. Soc. Geogr. Lima, Vol. 25, No. -3, 1909. For details of the trail from Rosalina to Pongo de Mainique see -“Plano de las Secciones y Afluentes del Rio Urubamba: 1902-1904,†scale -1:150,000 by Luis M. Robledo in Bol. Soc. Geogr. Lima, Vol. 25, No. 4, -1909. Only the lower slopes of the long mountain spurs can be seen from -the river; hence only in a few places could observations be made on the -topography of distant ranges. Paced distances of a half mile at -irregular intervals were used for the estimation of longer distances. -Directions were taken by compass corrected for magnetic deviation as -determined on the seventy-third meridian (See Appendix A). The position -of Rosalina on Robledo’s map was taken as a base." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 8—Sketch map showing the route of the Yale-Peruvian -Expedition of 1911 down the Urubamba Valley, together with the area of -the main map and the changes in the delineation of the bend of the -Urubamba resulting from the surveys of the Expedition. Based on the -“Mapa que comprende las ultimas exploraciones y estudios verificados -desde 1900 hasta 1906,†1:1,000,000, Bol. Soc. Geogr. Lima, Vol. 25, No. -3, 1909. For details of the trail from Rosalina to Pongo de Mainique see -“Plano de las Secciones y Afluentes del Rio Urubamba: 1902-1904,†scale -1:150,000 by Luis M. Robledo in Bol. Soc. Geogr. Lima, Vol. 25, No. 4, -1909. Only the lower slopes of the long mountain spurs can be seen from -the river; hence only in a few places could observations be made on the -topography of distant ranges. Paced distances of a half mile at -irregular intervals were used for the estimation of longer distances. -Directions were taken by compass corrected for magnetic deviation as -determined on the seventy-third meridian (See <a href="#APPENDIX_A">Appendix A</a>). The position -of Rosalina on Robledo’s map was taken as a base.</p> -</div> - -<p>We could gather almost no information as to the nature of the river -except from the report of Major Kerbey, an American, who, in 1897, -descended the last twenty miles of the one hundred we proposed to -navigate. He pronounced the journey more hazard<a name="page_009" id="page_009"></a><a name="page_010" id="page_010"></a>ous than Major Powell’s -famous descent of the Grand Canyon in 1867—an obvious exaggeration. He -lost his canoe in a treacherous rapid, was deserted by his Indian -guides, and only after a painful march through an all but impassable -jungle was he finally able to escape on an abandoned raft. Less than a -dozen have ventured down since Major Kerbey’s day. A Peruvian mining -engineer descended the river a few years ago, and four Italian traders a -year later floated down in rafts and canoes, losing almost all of their -cargo. For nearly two months they were marooned upon a sand-bar waiting -for the river to subside. At last they succeeded in reaching -Mulanquiato, an Indian settlement and plantation owned by Pereira, near -the entrance to the last canyon. Their attempted passage of the worst -stretch of rapids resulted in the loss of all their rubber cargo, the -work of a year. Among the half dozen others who have made the -journey—Indians and slave traders from down-river rubber posts—there -is no record of a single descent without the loss of at least one canoe.</p> - -<p>To reach the head of canoe navigation we made a two weeks’ muleback -journey north of Cuzco through the steep-walled granite Canyon of -Torontoy, and to the sugar and cacao plantations of the middle Urubamba, -or Santa Ana Valley, where we outfitted. At Echarati, thirty miles -farther on, where the heat becomes more intense and the first patches of -real tropical forest begin, we were obliged to exchange our beasts for -ten fresh animals accustomed to forest work and its privations. Three -days later we pitched our tent on the river bank at Rosalina, the last -outpost of the valley settlements. As we dropped down the steep mountain -slope before striking the river flood plain, we passed two half-naked -Machiganga Indians perched on the limbs of a tree beside the trail, our -first sight of members of a tribe whose territory we had now entered. -Later in the day they crossed the river in a dugout, landed on the -sand-bar above us, and gathered brush for the nightly fire, around which -they lie wrapped in a single shirt woven from the fiber of the wild -cotton.</p> - -<p><a name="fig_9" id="fig_9"></a></p> - -<p><a name="fig_10" id="fig_10"></a></p> - -<p class="figcenter"> -<a href="images/ill_page_010a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_010a_sml.jpg" width="312" height="211" alt="Fig. 9—The upper entrance to the Pongo de Mainique, -where the Urubamba crosses the Front Range of the Andes in a splendid -gateway 4,000 feet deep. The river is broken by an almost continuous -line of rapids." /></a> -</p> - -<table border="0" cellpadding="4" cellspacing="0" summary="" -style="max-width:50%;"> -<tr valign="top"><td class="swidth"><span class="caption"><span class="smcap">Fig. 9</span>—The upper entrance to the Pongo de Mainique, -where the Urubamba crosses the Front Range of the Andes in a splendid -gateway 4,000 feet deep. The river is broken by an almost continuous -line of rapids.</span></td> - -<td class="swidth"><span class="caption"><span class="smcap">Fig. 10</span>—The lower half of a two-thousand-foot cliff, -granite Canyon of Torontoy, Urubamba Valley. The wall is developed -almost entirely along joint planes. It is here that the Urubamba River -crosses the granite axis of the Cordillera Vilcapampa, the easternmost -system of the Andes of southern Peru. Compare also Figs. <a href="#fig_144">144</a> and <a href="#fig_145">145</a>.</span></td> -</tr> -</table> - -<p><a name="fig_11" id="fig_11"></a></p> -<p><a name="fig_12" id="fig_12"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_010b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_010b_sml.jpg" width="214" height="322" alt="Fig. 11—A temporary shelter-hut on a sand-bar near the -great bend of the Urubamba (see map, 8 ). The Machiganga Indians use -these cane shelters during the fishing season, when the river is low." /></a> -<br /> -<p class="caption"><span class="smcap">Fig. 11</span>—A temporary shelter-hut on a sand-bar near the -great bend of the Urubamba (see map, <a href="#fig_8">Fig. 8</a>). The Machiganga Indians use -these cane shelters during the fishing season, when the river is low.</p> - -<p class="caption"><span class="smcap">Fig. 12</span>—Thirty-foot canoe in a rapid above Pongo de -Mainique.</p> -</div> - -<p>Rosalina is hardly more than a name on the map and a camp site on the -river bank. Some distance back from the left bank of<a name="page_011" id="page_011"></a> the river is a -sugar plantation, whose owner lives in the cooler mountains, a day’s -journey away; on the right bank is a small clearing planted to sugar -cane and yuca, and on the edge of it is a reed hut sheltering three -inhabitants, the total population of Rosalina. The owner asked our -destination, and to our reply that we should start in a few days for -Pongo de Mainique he offered two serious objections. No one thought of -arranging so difficult a journey in less than a month, for canoe and -Indians were difficult to find, and the river trip was dangerous. -Clearly, to start without the loss of precious time would require -unusual exertion. We immediately despatched an Indian messenger to the -owner of the small hacienda across the river while one of our peons -carried a second note to a priest of great influence among the forest -Indians, Padre Mendoza, then at his other home in the distant mountains.</p> - -<p>The answer of Señor Morales was his appearance in person to offer the -hospitality of his home and to assist us in securing canoe and oarsmen. -To our note the Padre, from his hill-top, sent a polite answer and the -offer of his large canoe if we would but guarantee its return. His -temporary illness prevented a visit to which we had looked forward with -great interest.</p> - -<p>The morning after our arrival I started out on foot in company with our -<i>arriero</i> in search of the Machigangas, who fish and hunt along the -river bank during the dry season and retire to their hill camps when the -heavy rains begin. We soon left the well-beaten trail and, following a -faint woodland path, came to the river bank about a half day’s journey -below Rosalina. There we found a canoe hidden in an overhanging arch of -vines, and crossing the river met an Indian family who gave us further -directions. Their vague signs were but dimly understood and we soon -found ourselves in the midst of a <i>carrizo</i> (reed) swamp filled with -tall bamboo and cane and crossed by a network of interlacing streams. We -followed a faint path only to find ourselves climbing the adjacent -mountain slopes away from our destination. Once again in the swamp we -had literally to cut our way through the thick cane, wade the numberless -brooks, and follow wild animal<a name="page_012" id="page_012"></a> trails until, late in the day, famished -and thirsty, we came upon a little clearing on a sand-bar, the hut of La -Sama, who knew the Machigangas and their villages.</p> - -<p>After our long day’s work we had fish and yuca, and water to which had -been added a little raw cane sugar. Late at night La Sama returned from -a trip to the Indian villages down river. He brought with him a -half-dozen Machiganga Indians, boys and men, and around the camp fire -that night gave us a dramatic account of his former trip down river. At -one point he leaped to his feet, and with an imaginary pole shifted the -canoe in a swift rapid, turned it aside from imminent wreck, and -shouting at the top of his voice over the roar of the water finally -succeeded in evading what he had made seem certain death in a whirlpool. -We kept a fire going all night long for we slept upon the ground without -a covering, and, strange as it may appear, the cold seemed intense, -though the minimum thermometer registered 59° F. The next morning the -whole party of ten sunned themselves for nearly an hour until the flies -and heat once more drove them to shelter.</p> - -<p>Returning to camp next day by a different route was an experience of -great interest, because of the light it threw on hidden trails known -only to the Indian and his friends. Slave raiders in former years -devastated the native villages and forced the Indian to conceal his -special trails of refuge. At one point we traversed a cliff seventy-five -feet above the river, walking on a narrow ledge no wider than a man’s -foot. At another point the dim trail apparently disappeared, but when we -had climbed hand over hand up the face of the cliff, by hanging vines -and tree roots, we came upon it again. Crossing the river in the canoe -we had used the day before, we shortened the return by wading the swift -Chirumbia waist-deep, and by crawling along a cliff face for nearly an -eighth of a mile. At the steepest point the river had so under-cut the -face that there was no trail at all, and we swung fully fifteen feet -from one ledge to another, on a hanging vine high above the river.</p> - -<p>After two days’ delay we left Rosalina late in the afternoon of August -7. My party included several Machiganga Indians, La<a name="page_013" id="page_013"></a> Sama, and Dr. W. G. -Erving, surgeon of the expedition. Mr. P. B. Lanius, Moscoso (the -<i>arriero</i>), and two peons were to take the pack train as far as possible -toward the rubber station at Pongo de Mainique where preparations were -to be made for our arrival. At the first rapid we learned the method of -our Indian boatmen. It was to run the heavy boat head on into shallow -water at one side of a rapid and in this way “brake†it down stream. -Heavily loaded with six men, 200 pounds of baggage, a dog, and supplies -of yuca and sugar cane our twenty-five foot dugout canoe was as rigid as -a steamer, and we dropped safely down rapid after rapid until long after -dark, and by the light of a glorious tropical moon we beached our craft -in front of La Sama’s hut at the edge of the cane swamp.</p> - -<p>Here for five days we endured a most exasperating delay. La Sama had -promised Indian boatmen and now said none had yet been secured. Each day -Indians were about to arrive, but by nightfall the promise was broken -only to be repeated the following morning. To save our food supply—we -had taken but six days’ provisions—we ate yuca soup and fish and some -parched corn, adding to this only a little from our limited stores. At -last we could wait no longer, even if the map had to be sacrificed to -the work of navigating the canoe. Our determination to leave stirred La -Sama to final action. He secured an assistant named Wilson and embarked -with us, planning to get Indians farther down river or make the journey -himself.</p> - -<p>On August 12, at 4.30 P.M., we entered upon the second stage of the -journey. As we shot down the first long rapid and rounded a wooded bend -the view down river opened up and gave us our first clear notion of the -region we had set out to explore. From mountain summits in the clouds -long trailing spurs descend to the river bank. In general the slopes are -smooth-contoured and forest-clad from summit to base; only in a few -places do high cliffs diversify the scenery. The river vista everywhere -includes a rapid and small patches of <i>playa</i> or flood plain on the -inside of the river curves. Although a true canyon hems in the river at -two celebrated passes farther down, the upper part of the river<a name="page_014" id="page_014"></a> flows -in a somewhat open valley of moderate relief, with here and there a -sentinel-like peak next the river.</p> - -<p>A light shower fell at sunset, a typical late-afternoon downpour so -characteristic of the tropics. We landed at a small encampment of -Machigangas, built a fire against the scarred trunk of a big palm, and -made up our beds in the open, covering them with our rubber ponchos. Our -Indian neighbors gave us yuca and corn, but their neighborliness went no -further, for when our boatmen attempted to sleep under their roofs they -drove them out and fastened as securely as possible the shaky door of -their hut.</p> - -<p>All our efforts to obtain Indians, both here and elsewhere, proved -fruitless. One excuse after another was overcome; they plainly coveted -the trinkets, knives, machetes, muskets, and ammunition that we offered -them; and they appeared to be friendly enough. Only after repeated -assurances of our friendship could we learn the real reason for their -refusal. Some of them were escaped rubber pickers that had been captured -by white raiders several years before, and for them a return to the -rubber country meant enslavement, heavy floggings, and separation from -their numerous wives. The hardships they had endured, their final -escape, the cruelty of the rubber men, and the difficult passage of the -rapids below were a set of circumstances that nothing in our list of -gifts could overcome. My first request a week before had so sharpened -their memory that one of them related the story of his wrongs, a recital -intensely dramatic to the whole circle of his listeners, including -myself. Though I did not understand the details of his story, his tones -and gesticulations were so effective that they held me as well as his -kinsmen of the woods spellbound for over an hour.</p> - -<p>It is appalling to what extent this great region has been depopulated by -the slave raiders and those arch enemies of the savage, smallpox and -malaria. At Rosalina, over sixty Indians died of malaria in one year; -and only twenty years ago seventy of them, the entire population of the -Pongo, were swept away by smallpox. For a week we passed former camps -near small abandoned clearings, once the home of little groups of -Machigangas.<a name="page_015" id="page_015"></a> Even the summer shelter huts on the sand-bars, where the -Indians formerly gathered from their hill homes to fish, are now almost -entirely abandoned. Though our men carefully reconnoitered each one for -fear of ambush, the precaution was needless. Below the Coribeni the -Urubamba is a great silent valley. It is fitted by Nature to support -numerous villages, but its vast solitudes are unbroken except at night, -when a few families that live in the hills slip down to the river to -gather yuca and cane.</p> - -<p>By noon of the second day’s journey we reached the head of the great -rapid at the mouth of the Sirialo. We had already run the long Coribeni -rapid, visited the Indian huts at the junction of the big Coribeni -tributary, exchanged our canoe for a larger and steadier one, and were -now to run one of the ugliest rapids of the upper river. The rapid is -formed by the gravel masses that the Sirialo brings down from the -distant Cordillera Vilcapampa. They trail along for at least a -half-mile, split the river into two main currents and nearly choke the -mouth of the tributary. For almost a mile above this great barrier the -main river is ponded and almost as quiet as a lake.</p> - -<p>We let our craft down this rapid by ropes, and in the last difficult -passage were so roughly handled by our almost unmanageable canoe as to -suffer from several bad accidents. All of the party were injured in one -way or another, while I suffered a fracture sprain of the left foot that -made painful work of the rest of the river trip.</p> - -<p>At two points below Rosalina the Urubamba is shut in by steep mountain -slopes and vertical cliffs. Canoe navigation below the Sirialo and -Coribeni rapids is no more hazardous than on the rapids of our northern -rivers, except at the two “pongos†or narrow passages. The first occurs -at the sharpest point of the abrupt curve shown on the map; the second -is the celebrated Pongo de Mainique. In these narrow passages in time of -high water there is no landing for long stretches. The bow paddler -stands well forward and tries for depth and current; the stern paddler -keeps the canoe steady in its course. When paddlers are in agreement -even a heavy canoe can be directed into the most favorable channels.<a name="page_016" id="page_016"></a> -Our canoemen were always in disagreement, however, and as often as not -we shot down rapids at a speed of twenty miles an hour, broadside on, -with an occasional bump on projecting rocks or boulders whose warning -ordinary boatmen would not let go unheeded.</p> - -<p>The scenery at the great bend is unusually beautiful. The tropical -forest crowds the river bank, great cliffs rise sheer from the water’s -edge, their faces overhung with a trailing drapery of vines, and in the -longer river vistas one may sometimes see the distant heights of the -Cordillera Vilcapampa. We shot the long succession of rapids in the -first canyon without mishap, and at night pitched our tent on the edge -of the river near the mouth of the Manugali.</p> - -<p>From the sharp peak opposite our camp we saw for the first time the -phenomenon of cloud-banners. A light breeze was blowing from the western -mountains and its vapor was condensed into clouds that floated down the -wind and dissolved, while they were constantly forming afresh at the -summit. In the night a thunderstorm arose and swept with a roar through -the vast forest above us. The solid canopy of the tropical forest fairly -resounded with the impact of the heavy raindrops. The next morning all -the brooks from the farther side of the river were in flood and the -river discolored. When we broke camp the last mist wraiths of the storm -were still trailing through the tree-tops and wrapped about the peak -opposite our camp, only parting now and then to give us delightful -glimpses of a forest-clad summit riding high above the clouds.</p> - -<p>The alternation of deeps and shallows at this point in the river and the -well-developed canyon meanders are among the most celebrated of their -kind in the world. Though shut in by high cliffs and bordered by -mountains the river exhibits a succession of curves so regular that one -might almost imagine the country a plain from the pattern of the -meanders. The succession of smooth curves for a long distance across -existing mountains points to a time when a lowland plain with moderate -slopes drained by strongly meandering rivers was developed here. Uplift -afforded<a name="page_017" id="page_017"></a> a chance for renewed down-cutting on the part of all the -streams, and the incision of the meanders. The present meanders are, of -course, not the identical ones that were formed on the lowland plain; -they are rather their descendants. Though they still retain their -strongly curved quality, and in places have almost cut through the -narrow spurs between meander loops, they are not smooth like the -meanders of the Mississippi. Here and there are sharp irregular turns -that mar the symmetry of the larger curves. The alternating bands of -hard and soft rock have had a large part in making the course more -irregular. The meanders have responded to the rock structure. Though -regular in their broader features they are irregular and deformed in -detail.</p> - -<p>Deeps and shallows are known in every vigorous river, but it is seldom -that they are so prominently developed as in these great canyons. At one -point in the upper canyon the river has been broadened into a lake two -or three times the average width of the channel and with a scarcely -perceptible current; above and below the “laguna,†as the boatmen call -it, are big rapids with beds so shallow that rocks project in many -places. In the Pongo de Mainique the river is at one place only fifty -feet wide, yet so deep that there is little current. It is on the banks -of the quiet stretches that the red forest deer grazes under leafy -arcades. Here, too, are the boa-constrictor trails several feet wide and -bare like a roadway. At night the great serpents come trailing down to -the river’s edge, where the red deer and the wildcat, or so-called -“tiger,†are their easy prey.</p> - -<p>It is in such quiet stretches that one also finds the vast colonies of -water skippers. They dance continuously in the sun with an incessant -motion from right to left and back again. Occasionally one dances about -in circles, then suddenly darts through the entire mass, though without -striking his equally erratic neighbors. An up-and-down motion still -further complicates the effect. It is positively bewildering to look -intently at the whirling multitude and try to follow their complicated -motions. Every slight breath of wind brings a shock to the organization -of the dance. For though they dance only in the sun, their favorite -places are the sunny<a name="page_018" id="page_018"></a> spots in the shade near the bank, as beneath an -overhanging tree. When the wind shakes the foliage the mottled pattern -of shade and sunlight is confused, the dance slows down, and the dancers -become bewildered. In a storm they seek shelter in the jungle. The hot, -quiet, sunlit days bring out literally millions of these tiny creatures.</p> - -<p>One of the longest deeps in the whole Urubamba lies just above the Pongo -at Mulanquiato. We drifted down with a gentle current just after sunset. -Shrill whistles, like those of a steam launch, sounded from either bank, -the strange piercing notes of the lowland cicada, <i>cicada tibicen</i>. Long -decorated canoes, better than any we had yet seen, were drawn up in the -quiet coves. Soon we came upon the first settlement. The owner, Señor -Pereira, has gathered about him a group of Machigangas, and by marrying -into the tribe has attained a position of great influence among the -Indians. Upon our arrival a gun was fired to announce to his people that -strangers had come, upon which the Machigangas strolled along in twos -and threes from their huts, helped us ashore with the baggage, and -prepared the evening meal. Here we sat down with five Italians, who had -ventured into the rubber fields with golden ideas as to profits. After -having lost the larger part of their merchandise, chiefly cinchona, in -the rapids the year before, they had established themselves here with -the idea of picking rubber. Without capital, they followed the ways of -the itinerant rubber picker and had gathered “caucho,†the poorer of the -two kinds of rubber. No capital is required; the picker simply cuts down -the likeliest trees, gathers the coagulated sap, and floats it -down-stream to market. After a year of this life they had grown restless -and were venturing on other schemes for the great down-river rubber -country.</p> - -<p><a name="fig_13" id="fig_13"></a></p> - -<p><a name="fig_14" id="fig_14"></a></p> - -<p class="figcenter"> -<a href="images/ill_page_018a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_018a_sml.jpg" width="313" height="216" alt="Fig. 13—Composition of tropical vegetation in the rain -forest above Pongo de Mainique, elevation 2,500 feet (760 m.). Scores of -species occur within the limits of a single photograph." /></a></p> - -<table border="0" cellpadding="4" cellspacing="0" summary="" -style="max-width:50%;" class="caption"> -<tr valign="top"><td class="swidth"><span class="smcap">Fig. 13—</span>Composition of tropical vegetation in the rain -forest above Pongo de Mainique, elevation 2,500 feet (760 m.). Scores of -species occur within the limits of a single photograph.</td> - -<td class="swidth"><span class="smcap">Fig. 14</span>—The mule trail in the rain forest between -Rosalina and Pongo de Mainique. Each pool is from one and a half to two -feet deep. Even in the dry season these holes are full of water, for the -sunlight penetrates the foliage at a few places only.</td></tr> -</table> - -<p><a name="fig_15" id="fig_15"></a></p> - -<p><a name="fig_16" id="fig_16"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_018b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_018b_sml.jpg" width="214" height="327" alt="Fig. 15—Topography and vegetation from the Tocate pass, -7,100 feet (2,164 m.), between Rosalina and Pongo de Mainique. See -Fig. 53a. This is in the zone of maximum rainfall. The cumulo-nimbus clouds -are typical and change to nimbus in the early afternoon." /></a> -<br /> -<p class="caption"><span class="smcap">Fig. 15</span>—Topography and vegetation from the Tocate pass, -7,100 feet (2,164 m.), between Rosalina and Pongo de Mainique. See <a href="#fig_53">Fig. 53a.</a> This is in the zone of maximum rainfall. The cumulo-nimbus clouds -are typical and change to nimbus in the early afternoon.</p> - -<p class="caption"><span class="smcap">Fig</span>. 16—The Expedition’s thirty-foot canoe at the mouth -of the Timpia below Pongo de Mainique.</p></div> - -<p>A few weeks later, on returning through the forest, we met their -carriers with a few small bundles, the only part of their cargo they had -saved from the river. Without a canoe or the means to buy one they had -built rafts, which were quickly torn to pieces in the rapids. We, too, -should have said “<i>pobres Italianos</i>†if their venture had not been -plainly foolish. The rubber territory<a name="page_019" id="page_019"></a> is difficult enough for men -with capital; for men without capital it is impossible. Such men either -become affiliated with organized companies or get out of the region when -they can. A few, made desperate by risks and losses, cheat and steal -their way to rubber. Two years before our trip an Italian had murdered -two Frenchmen just below the Pongo and stolen their rubber cargo, -whereupon he was shot by Machigangas under the leadership of Domingo, -the chief who was with us on a journey from Pongo de Mainique to the -mouth of the Timpia. Afterward they brought his skull to the top of a -pass along the forest trail and set it up on a cliff at the very edge of -Machiganga-land as a warning to others of his kind.</p> - -<p>At Mulanquiato we secured five Machigangas and a boy interpreter, and on -August 17 made the last and most difficult portion of our journey. We -found these Indians much more skilful than our earlier boatmen. -Well-trained, alert, powerful, and with excellent team-play, they swept -the canoe into this or that thread of the current, and took one after -another of the rapids with the greatest confidence. No sooner had we -passed the Sintulini rapids, fully a mile long, than we reached the -mouth of the Pomareni. This swift tributary comes in almost at right -angles to the main river and gives rise to a confusing mass of standing -waves and conflicting currents rendered still more difficult by the -whirlpool just below the junction. So swift is the circling current of -the maëlstrom that the water is hollowed out like a great bowl, a really -formidable point and one of our most dangerous passages; a little too -far to the right and we should be thrown over against the cliff-face; a -little too far to the left and we should be caught in the whirlpool. -Once in the swift current the canoe became as helpless as a chip. It was -turned this way and that, each turn heading it apparently straight for -destruction. But the Indians had judged their position well, and though -we seemed each moment in a worse predicament, we at last skimmed the -edge of the whirlpool and brought our canoe to shore just beyond its -rim.</p> - -<p>A little farther on we came to the narrow gateway of the Pongo, where -the entire volume of the river flows between cliffs<a name="page_020" id="page_020"></a> at one point no -more than fifty feet apart. Here are concentrated the worst rapids of -the lower Urubamba. For nearly fifteen miles the river is an unbroken -succession of rapids, and once within its walls the Pongo offers small -chance of escape. At some points we were fortunate enough to secure a -foothold along the edge of the river and to let our canoe down by ropes. -At others we were obliged to take chances with the current, though the -great depth of water in most of the Pongo rapids makes them really less -formidable in some respects than the shallow rapids up stream. The chief -danger here lies in the rotary motion of the water at the sharpest -bends. The effect at some places is extraordinary. A floating object is -carried across stream like a feather and driven at express-train speed -against a solid cliff. In trying to avoid one of these cross-currents -our canoe became turned midstream, we were thrown this way and that, and -at last shot through three standing waves that half filled the canoe.</p> - -<p>Below the worst rapids the Pongo exhibits a swift succession of natural -wonders. Fern-clad cliffs border it, a bush resembling the juniper -reaches its dainty finger-like stems far out over the river, and the -banks are heavily clad with mosses. The great woods, silent, -impenetrable, mantle the high slopes and stretch up to the limits of -vision. Cascades tumble from the cliff summits or go rippling down the -long inclines of the slate beds set almost on edge. Finally appear the -white pinnacles of limestone that hem in the narrow lower entrance or -outlet of the Pongo. Beyond this passage one suddenly comes out upon the -edge of a rolling forest-clad region, the rubber territory, the country -of the great woods. Here the Andean realm ends and Amazonia begins.</p> - -<p>From the summits of the white cliffs 4,000 feet above the river we were -in a few days to have one of the most extensive views in South America. -The break between the Andean Cordillera and the hill-dotted plains of -the lower Urubamba valley is almost as sharp as a shoreline. The rolling -plains are covered with leagues upon leagues of dense, shadowy, -fever-haunted jungle. The great river winds through in a series of -splendid meanders, and with so broad a channel as to make it visible -almost to the horizon. Down river<a name="page_021" id="page_021"></a> from our lookout one can reach ocean -steamers at Iquitos with less than two weeks of travel. It is three -weeks to the Pacific <i>via</i> Cuzco and more than a month if one takes the -route across the high bleak lava-covered country which we were soon to -cross on our way to the coast at Camaná.<a name="page_022" id="page_022"></a></p> - -<h3><a name="CHAPTER_III" id="CHAPTER_III"></a>CHAPTER III<br /><br /> -THE RUBBER FORESTS</h3> - -<p>T<small>HE</small> white limestone cliffs at Pongo de Mainique are a boundary between -two great geographic provinces (<a href="#fig_17">Fig. 17</a>). Down valley are the vast river -plains, drained by broad meandering rivers; up valley are the rugged -spurs of the eastern Andes and their encanyoned streams (<a href="#fig_18">Fig. 18</a>). There -are outliers of the Andes still farther toward the northeast where hangs -the inevitable haze of the tropical horizon, but the country beyond them -differs in no important respect from that immediately below the Pongo.</p> - -<p><a name="fig_17" id="fig_17"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_022_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_022_sml.jpg" width="410" height="313" alt="Fig. 17—Regional diagram of the Eastern Andes (here the -Cordillera Vilcapampa) and the adjacent tropical plains. For an -explanation of the method of construction and the symbolism of the -diagram see p. 51." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 17—Regional diagram of the Eastern Andes (here the -Cordillera Vilcapampa) and the adjacent tropical plains. For an -explanation of the method of construction and the symbolism of the -diagram see <a href="#page_051">p. 51</a>.</p> -</div> - -<p>The foot-path to the summit of the cliffs is too narrow and<a name="page_023" id="page_023"></a> steep for -even the most agile mules. It is simply impassable for animals without -hands. In places the packs are lowered by ropes over steep ledges and -men must scramble down from one projecting root or swinging vine to -another. In the breathless jungle it is a wearing task to pack in all -supplies for the station below the Pongo and to carry out the season’s -rubber. Recently however the ancient track has been replaced by a road -that was cut with great labor, and by much blasting, across the mountain -barrier, and at last mule transport has taken the place of the Indian.</p> - -<p><a name="fig_18" id="fig_18"></a></p> - -<div class="figright" style="width: 120px;"> -<a href="images/ill_page_023_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_023_sml.jpg" width="120" height="315" alt="Fig. 18—Index map for the nine regional diagrams in the -pages following. A represents Fig. 17; B, 42; C, 36; D, 32; E, 34; F, -25; G, 26; and H, 65." /></a> -<br /> -<span class="caption">Fig. 18—Index map for the nine regional diagrams in the -pages following. A represents <a href="#fig_17">17</a> ; B, 42; C, 36; D, 32; E, 34; F, -25; G, 26; and H, 65.</span> -</div> - -<p>In the dry season it is a fair and delightful country—that on the -border of the mountains. In the wet season the traveler is either -actually marooned or he must slosh through rivers of mud and water that -deluge the trails and break the hearts of his beasts (<a href="#fig_14">Fig. 14</a>). Here and -there a<a name="page_024" id="page_024"></a> large shallow-rooted tree has come crashing down across the -trail and with its four feet of circumference and ten feet of plank -buttress it is as difficult to move as a house. A new trail must be cut -around it. A little farther on, where the valley wall steepens and one -may look down a thousand feet of slope to the bed of a mountain torrent, -a patch of trail has become soaked with water and the mules pick their -way, trembling, across it. Two days from Yavero one of our mules went -over the trail, and though she was finally recovered she died of her -injuries the following night. After a month’s work in the forest a mule -must run free for two months to recover. The packers count on losing one -beast out of five for every journey into the forest. It is not solely a -matter of work, though this is terrific; it is quite largely a matter of -forage. In spite of its profusion of life (<a href="#fig_13">Fig. 13</a>) and its really vast -wealth of species, the tropical forest is all but barren of grass. Sugar -cane is a fair substitute, but there are only a few cultivated spots. -The more tender leaves of the trees, the young shoots of cane in the -<i>carrizo</i> swamps, and the grass-like foliage of the low bamboo are the -chief substitutes for pasture. But they lead to various disorders, -besides requiring considerable labor on the part of the dejected peons -who must gather them after a day’s heavy work with the packs.</p> - -<p>Overcoming these enormous difficulties is expensive and some one must -pay the bill. As is usual in a pioneer region, the native laborer pays a -large part of it in unrequited toil; the rest is paid by the rubber -consumer. For this is one of the cases where a direct road connects the -civilized consumer and the barbarous producer. What a story it could -tell if a ball of smoke-cured rubber on a New York dock were endowed -with speech—of the wet jungle path, of enslaved peons, of vile abuses -by immoral agents, of all the toil and sickness that make the tropical -lowland a reproach!</p> - -<p><a name="fig_19" id="fig_19"></a></p> -<p><a name="fig_20" id="fig_20"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_024a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_024a_sml.jpg" width="207" height="323" alt="Fig. 19—Moss-draped trees in the rain forest near Abra -Tocate between Rosalina and Pongo de Mainique." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 19—Moss-draped trees in the rain forest near Abra -Tocate between Rosalina and Pongo de Mainique.</p> - -<p class="caption"> -<span class="smcap">Fig. 20</span>—Yavero, a rubber station on the Yavero -(Paucartambo) River, a tributary of the Urubamba. Elevation 1,600 feet -(490 m.).</p></div> - -<p>In the United States the specter of slavery haunted the national -conscience almost from the beginning of national life, and the ghost was -laid only at the cost of one of the bloodiest wars in history. In other -countries, as in sugar-producing Brazil, the freeing of the slaves meant -not a war but the verge of financial<a name="page_025" id="page_025"></a> ruin besides a fundamental -change in the social order and problems as complex and wearisome as any -that war can bring. Everywhere abolition was secured at frightful cost.</p> - -<p><a name="fig_21" id="fig_21"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_024b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_024b_sml.jpg" width="213" height="329" alt="Fig. 21—Clearing in the tropical forest between Rosalina -and Pabellon. This represents the border region where the -forest-dwelling Machiganga Indians and the mountain Indians meet. The -clearings are occupied by Machigangas whose chief crops are yuca and -corn; in the extreme upper left-hand corner are grassy slopes occupied -by Quechua herdsmen and farmers who grow potatoes and corn." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 21—Clearing in the tropical forest between Rosalina -and Pabellon. This represents the border region where the -forest-dwelling Machiganga Indians and the mountain Indians meet. The -clearings are occupied by Machigangas whose chief crops are yuca and -corn; in the extreme upper left-hand corner are grassy slopes occupied -by Quechua herdsmen and farmers who grow potatoes and corn.</p> -</div> - -<p>The spirit that upheld the new founders of the western republics in -driving out slavery was admirable, but as much cannot be said of their -work of reconstruction. We like to pass over those dark days in our own -history. In South America there has lingered from the old slave-holding -days down to the present, a labor system more insidious than slavery, -yet no less revolting in its details, and infinitely more difficult to -stamp out. It is called peonage; it should be called slavery. In -Bolivia, Peru, and Brazil it flourishes now as it ever did in the -fruitful soil of the interior provinces where law and order are bywords -and where the scarcity of workmen will long impel men to enslave labor -when they cannot employ it. Peonage <i>is</i> slavery, though as in all slave -systems there are many forms under which the system is worked out. We -commonly think that the typical slave is one who is made to work hard, -given but little food, and at the slightest provocation is tied to a -post and brutally whipped. This is indeed the fate of many slaves or -“peons†so-called, in the Amazon forests; but it is no more the rule -than it was in the South before the war, for a peon is a valuable piece -of property and if a slave raider travel five hundred miles through -forest and jungle-swamp to capture an Indian you may depend upon it that -he will not beat him to death merely for the fun of it.</p> - -<p>That unjust and frightfully cruel floggings are inflicted at times and -in some places is of course a result of the lack of official restraint -that drunken owners far from the arm of the law sometimes enjoy. When a -man obtains a rubber concession from the government he buys a kingdom. -Many of the rubber territories are so remote from the cities that -officials can with great difficulty be secured to stay at the customs -ports. High salaries must be paid, heavy taxes collected, and grafting -of the most flagrant kind winked at. Often the concessionaire himself is -chief magistrate of his kingdom by law. Under such a system, remote from -all civilizing influences, the rubber producer himself oftentimes a -lawless<a name="page_026" id="page_026"></a> border character or a downright criminal, no system of -government would be adequate, least of all one like peonage that permits -or ignores flagrant wrongs because it is so expensive to enforce -justice.</p> - -<p>The peonage system continues by reason of that extraordinary difficulty -in the development of the tropical lowland of South America—the lack of -a labor supply. The population of Amazonia now numbers less than one -person to the square mile. The people are distributed in small groups of -a dozen to twenty each in scattered villages along the river banks or in -concealed clearings reached by trails known only to the Indians. Nearly -all of them still live in the same primitive state in which they lived -at the time of the Discovery. In the Urubamba region a single cotton -shirt is worn by the married men and women, while the girls and boys in -many cases go entirely naked except for a loincloth or a necklace of -nuts or monkeys’ teeth (<a href="#fig_23">Fig. 23</a>). A cane hut with a thatch to keep out -the heavy rains is their shelter and their food is the yuca, sugar cane, -Indian corn, bananas of many kinds, and fish. A patch of yuca once -planted will need but the most trifling attention for years. The small -spider monkey is their greatest delicacy and to procure it they will -often abandon every other project and return at their own sweet and -belated will.</p> - -<p><a name="fig_22" id="fig_22"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_026a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_026a_sml.jpg" width="346" height="222" alt="Fig. 22—Trading with Machiganga Indians in a reed swamp -at Santao Anato, Urubamba Valley, before Rosalina. Just outside the -picture on the right is a platform on which corn is stored for -protection against rodents and mildew. On the left is the corner of a -grass-thatched cane hut." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 22—Trading with Machiganga Indians in a reed swamp -at Santao Anato, Urubamba Valley, before Rosalina. Just outside the -picture on the right is a platform on which corn is stored for -protection against rodents and mildew. On the left is the corner of a -grass-thatched cane hut.</p> -</div> - -<p>In the midst of this natural life of the forest-dwelling Indian appears -the rubber man, who, to gather rubber, must have rubber “pickers.†If he -lives on the edge of the great Andean Cordillera, laborers may be -secured from some of the lower valleys, but they must be paid well for -even a temporary stay in the hot and unhealthful lowlands. Farther out -in the great forest country the plateau Indians will not go and only the -scattered tribes remain from which to recruit laborers. For the -nature-life of the Indian what has the rubber gatherer to offer? Money? -The Indian uses it for ornament only. When I once tried with money to -pay an Indian for a week’s services he refused it. In exchange for his -severe labor he wanted nothing more than a fish-hook and a ring, the two -costing not more than a penny apiece! When his love for ornament has -once been gratified the Indian ceases to work. His<a name="page_027" id="page_027"></a> food and shelter -and clothing are of the most primitive kind, but they are the best in -the world for him because they are the only kind he has known. So where -money and finery fail the lash comes in. The rubber man says that the -Indian is lazy and must be made to work; that there is a great deal of -work to be done and the Indian is the only laborer who can be found; -that if rubber and chocolate are produced the Indian must be made to -produce them; and that if he will not produce them for pay he must be -enslaved.</p> - -<p><a name="fig_23" id="fig_23"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_026b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_026b_sml.jpg" width="331" height="213" alt="Fig. 23—Ornaments and fabrics of the Machiganga Indians -at Yavero. The nuts are made up into strings, pendants, and heavy -necklaces. To the left of the center is one that contains feathers and -four drumsticks of a bird about the size of a small wild -turkey—probably the so-called turkey inhabiting the eastern mountain -valleys and the adjacent border of the plains, and hunted as an -important source of food. The cord in the upper right-hand corner is -used most commonly for heel supports in climbing trees. The openwork -sack is convenient for carrying game, fish, and fruit; the finely woven -sacks are used for carrying red ochre for ornamenting or daubing faces -and arms. They are also used for carrying corn, trinkets, and game." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 23—Ornaments and fabrics of the Machiganga Indians -at Yavero. The nuts are made up into strings, pendants, and heavy -necklaces. To the left of the center is one that contains feathers and -four drumsticks of a bird about the size of a small wild -turkey—probably the so-called turkey inhabiting the eastern mountain -valleys and the adjacent border of the plains, and hunted as an -important source of food. The cord in the upper right-hand corner is -used most commonly for heel supports in climbing trees. The openwork -sack is convenient for carrying game, fish, and fruit; the finely woven -sacks are used for carrying red ochre for ornamenting or daubing faces -and arms. They are also used for carrying corn, trinkets, and game.</p> -</div> - -<p>It is a law of the rubber country that when an Indian falls into debt to -a white man he must work for the latter until the debt is discharged. If -he runs away before the debt is canceled or if he refuses to work or -does too little work he may be flogged. Under special conditions such -laws are wise. In the hands of the rubber men they are the basis of -slavery. For, once the rubber interests begin to suffer, the promoters -look around for a chance to capture free Indians. An expedition is -fitted out that spends weeks exploring this river or that in getting on -the track of unattached Indians. When a settlement is found the men are -enslaved and taken long distances from home finally to reach a rubber -property. There they are given a corner of a hut to sleep in, a few -cheap clothes, a rubber-picking outfit, and a name. In return for these -articles the unwilling Indian is charged any fanciful price that comes -into the mind of his “owner,†and he must thereupon work at a per diem -wage also fixed by the owner. Since his obligations increase with time, -the Indian may die over two thousand dollars in debt!</p> - -<p>Peonage has left frightful scars upon the country. In some places the -Indians are fugitives, cultivating little farms in secreted places but -visiting them only at night or after carefully reconnoitering the spot. -They change their camps frequently and make their way from place to -place by secret trails, now spending a night or two under the shelter of -a few palm leaves on a sandbar, again concealing themselves in almost -impenetrable jungle. If the hunter sometimes discovers a beaten track he -follows it only to find it ending on a cliff face or on the edge of a -lagoon where<a name="page_028" id="page_028"></a> concealment is perfect. There are tribes that shoot the -white man at sight and regard him as their bitterest enemy. Experience -has led them to believe that only a dead white is a good white, -reversing our saying about the North American Indian; and that even when -he comes among them on peaceful errands he is likely to leave behind him -a trail of syphilis and other venereal diseases scarcely less deadly -than his bullets.</p> - -<p>However, the peonage system is not hideous everywhere and in all its -aspects. There are white owners who realize that in the long run the -friendship of the Indians is an asset far greater than unwilling service -and deadly hatred. Some of them have indeed intermarried with the -Indians and live among them in a state but little above savagery. In the -Mamoré country are a few owners of original princely concessions who -have grown enormously wealthy and yet who continue to live a primitive -life among their scores of illegitimate descendants. The Indians look -upon them as benefactors, as indeed many of them are, defending the -Indians from ill treatment by other whites, giving them clothing and -ornaments, and exacting from them only a moderate amount of labor. In -some cases indeed the whites have gained more than simple gratitude for -their humane treatment of the Indians, some of whom serve their masters -with real devotion.</p> - -<p>When the “rubber barons†wish to discourage investigation of their -system they invite the traveler to leave and he is given a canoe and -oarsmen with which to make his way out of the district. Refusal to -accept an offer of canoes and men is a declaration of war. An agent of -one of the London companies accepted such a challenge and was promptly -told that he would not leave the territory alive. The threat would have -held true in the case of a less skilful man. Though Indians slept in the -canoes to prevent their seizure, he slipped past the guards in the -night, swam to the opposite shore, and there secured a canoe within -which he made a difficult journey down river to the nearest post where -food and an outfit could be secured.</p> - -<p>A few companies operating on or near the border of the Cordillera have -adopted a normal labor system, dependent chiefly upon<a name="page_029" id="page_029"></a> people from the -plateau and upon the thoroughly willing assistance of well-paid forest -Indians. The Compañia Gomera de Mainique at Puerto Mainique just below -the Pongo is one of these and its development of the region without -violation of native rights is in the highest degree praiseworthy. In -fact the whole conduct of this company is interesting to a geographer, -as it reflects at every point the physical nature of the country.</p> - -<p>The government is eager to secure foreign capital, but in eastern Peru -can offer practically nothing more than virgin wealth, that is, land and -the natural resources of the land. There are no roads, virtually no -trails, no telegraph lines, and in most cases no labor. Since the old -Spanish grants ran at right angles to the river so as to give the owners -a cross-section of varied resources, the up-river plantations do not -extend down into the rubber country. Hence the more heavily forested -lower valleys and plains are the property of the state. A man can buy a -piece of land down there, but from any tract within ordinary means only -a primitive living can be obtained. The pioneers therefore are the -rubber men who produce a precious substance that can stand the enormous -tax on production and transportation. They do not want the land—only -the exclusive right to tap the rubber trees upon it. Thus there has -arisen the concession plan whereby a large tract is obtained under -conditions of money payment or of improvements that will attract -settlers or of a tax on the export.</p> - -<p>The “caucho†or poorer rubber of the Urubamba Valley begins at 3,000 -feet (915 m.) and the “hevea†or better class is a lower-valley and -plains product. The rubber trees thereabouts produce 60 grams (2 ozs.) -of dry rubber each week for eight months. After yielding rubber for this -length of time a tree is allowed to rest four or five years. “Caucho†is -produced from trees that are cut down and ringed with machetes, but it -is from fifty to sixty cents cheaper owing to the impurities that get -into it. The wood, not the nut, of the <i>Palma carmona</i> is used for -smoking or “curing†the rubber. The government had long been urged to -build a road into the region in place of the miserable track—absolutely -impassable in the wet season—that heretofore<a name="page_030" id="page_030"></a> constituted the sole -means of exit. About ten years ago Señor Robledo at last built a -government trail from Rosalina to Yavero about 100 miles long. While it -is a wretched trail it is better than the old one, for it is more direct -and it is better drained. In the wet season parts of it are turned into -rivers and lakes, but it is probably the best that could be done with -the small grant of twenty thousand dollars.</p> - -<p>With at least an improvement in the trail it became possible for a -rubber company to induce <i>cargadores</i> or packers to transport -merchandise and rubber and to have a fair chance of success. Whereupon a -rubber company was organized which obtained a concession of 28,000 -hectares (69,188 acres) of land on condition that the company finish a -road one and one-half meters wide to the Pongo, connecting with the road -which the government had extended to Yavero. The land given in payment -was not continuous but was selected in lots by the company in such a way -as to secure the best rubber trees over an area several times the size -of the concession. The road was finished by William Tell after four -years’ work at a cost of about seventy-five thousand dollars. The last -part of it was blasted out of slate and limestone and in 1912 the first -pack train entered Puerto Mainique.</p> - -<p>The first rubber was taken out in November, 1910, and productive -possibilities proved by the collection of 9,000 kilos (19,841 pounds) in -eight months.</p> - -<p>If a main road were the chief problem of the rubber company the business -would soon be on a paying basis, but for every mile of road there must -be cut several miles of narrow trail (<a href="#fig_14">Fig. 14</a>), as the rubber trees grow -scattered about—a clump of a half dozen here and five hundred feet -farther on another clump and only scattered individuals between. -Furthermore, about twenty-five years ago rubber men from the Ucayali -came up here in launches and canoes and cut down large numbers of trees -within reach of the water courses and by ringing the trunks every few -feet with machetes “bled†them rapidly and thus covered a large -territory in a short time, and made huge sums of money when the price of -rubber was high. Only a few of the small trees that were left<a name="page_031" id="page_031"></a> are now -mature. These, the mature trees that were overlooked, and the virgin -stands farther from the rivers are the present sources of rubber.</p> - -<p>In addition to the trails small cabins must be built to shelter the -hired laborers from the plateau, many of whom bring along their women -folk to cook for them. The combined expense to a company of these -necessary improvements before production can begin is exceedingly heavy. -There is only one alternative for the prospective exploiter: to become a -vagrant rubber gatherer. With tents, guns, machetes, cloth, baubles for -trading, tinned food for emergencies, and with pockets full of English -gold parties have started out to seek fortunes in the rubber forests. If -the friendship of a party of Indians can be secured by adequate gifts -large amounts of rubber can be gathered in a short time, for the Indians -know where the rubber trees grow. On the other hand, many fortunes have -been lost in the rubber country. Some of the tribes have been badly -treated by other adventurers and attack the newcomers from ambush or -gather rubber for a while only to overturn the canoe in a rapid and let -the river relieve them of selfish friends.</p> - -<p>The Compañia Gomera de Mainique started out by securing the good-will of -the forest Indians, the Machigangas. They come and go in friendly visits -to the port at Yavero. If one of them is sick he can secure free -medicine from the agent. If he wishes goods on credit he has only to ask -for them, for the agent knows that the Indian’s sense of fairness will -bring him back to work for the company. Without previous notice a group -of Indians appears:</p> - -<p>“We owe,†they announce.</p> - -<p>“Good,†says the agent, “build me a house.â€</p> - -<p>They select the trees. Before they cut them down they address them -solemnly. The trees must not hold their destruction against the Indians -and they must not try to resist the sharp machetes. Then the Indians set -to work. They fell a tree, bind it with light ropes woven from the wild -cotton, and haul it to its place. That is all for the day. They play in -the sun, do a little hunting, or<a name="page_032" id="page_032"></a> look over the agent’s house, touching -everything, talking little, exclaiming much. They dip their wet fingers -in the sugar bowl and taste, turn salt out upon their hands, hold -colored solutions from the medicine chest up to the light, and pull out -and push in the corks of the bottles. At the end of a month or two the -house is done. Then they gather their women and babies together and say:</p> - -<p>“Now we go,†without asking if the work corresponds with the cost of the -articles they had bought. Their judgment is good however. Their work is -almost always more valuable than the articles. Then they shake hands all -around.</p> - -<p>“We will come again,†they say, and in a moment have disappeared in the -jungle that overhangs the trail.</p> - -<p>With such labor the Compañia Gomera de Mainique can do something, but it -is not much. The regular seasonal tasks of road-building and -rubber-picking must be done by imported labor. This is secured chiefly -at Abancay, where live groups of plateau Indians that have become -accustomed to the warm climate of the Abancay basin. They are employed -for eight or ten months at an average rate of fifty cents gold per day, -and receive in addition only the simplest articles of food.</p> - -<p>At the end of the season the gang leaders are paid a <i>gratificación</i>, or -bonus, the size of which depends upon the amount of rubber collected, -and this in turn depends upon the size of the gang and the degree of -willingness to work. In the books of the company I saw a record of -<i>gratificaciónes</i> running as high as $600 in gold for a season’s work.</p> - -<p>Some of the laborers become sick and are cared for by the agent until -they recover or can be sent back to their homes. Most of them have fever -before they return.</p> - -<p>The rubber costs the company two <i>soles</i> ($1.00) produced at Yavero. The -two weeks’ transportation to Cuzco costs three and a half soles ($1.75) -per twenty-five pounds. The exported rubber, known to the trade as -Mollendo rubber, in contrast to the finer “Pará†rubber from the lower -Amazon, is shipped to Hamburg. The cost for transportation from port to -port is $24.00 per English ton (1,016 kilos). There is a Peruvian tax of -8 per cent of<a name="page_033" id="page_033"></a> the net value in Europe, and a territorial tax of two -soles ($1.00) per hundred pounds. All supplies except the few vegetables -grown on the spot cost tremendously. Even dynamite, hoes, clothing, -rice—to mention only a few necessities—must pay the heavy cost of -transportation after imposts, railroad and ocean freight, storage and -agents’ percentages are added. The effect of a disturbed market is -extreme. When, in 1911, the price of rubber fell to $1.50 a kilo at -Hamburg the company ceased exporting. When it dropped still lower in -1912 production also stopped, and it is still doubtful, in view of the -growing competition of the East-Indian plantations with their cheap -labor, whether operations will ever be resumed. Within three years no -less than a dozen large companies in eastern Peru and Bolivia have -ceased operations. In one concession on the Madre de Dios the withdrawal -of the agents and laborers from the posts turned at last into flight, as -the forest Indians, on learning the company’s policy, rapidly ascended -the river in force, committing numerous depredations. The great war has -also added to the difficulties of production.</p> - -<p>Facts like these are vital in the consideration of the future of the -Amazon basin and especially its habitability. It was the dream of -Humboldt that great cities should arise in the midst of the tropical -forests of the Amazon and that the whole lowland plain of that river -basin should become the home of happy millions. Humboldt’s vision may -have been correct, though a hundred years have brought us but little -nearer its realization. Now, as in the past four centuries, man finds -his hands too feeble to control the great elemental forces which have -shaped history. The most he can hope for in the next hundred years at -least is the ability to dodge Nature a little more successfully, and -here and there by studies in tropical hygiene and medicine, by the -substitution of water-power for human energy, to carry a few of the -outposts and prepare the way for a final assault in the war against the -hard conditions of climate and relief. We hear of the Madeira-Mamoré -railroad, 200 miles long, in the heart of a tropical forest and of the -commercial revolution it will bring. Do we realize that the forest which -overhangs the rails is as big as the whole plain<a name="page_034" id="page_034"></a> between the Rockies -and the Appalachians, and that the proposed line would extend only as -far as from St. Louis to Kansas City, or from Galveston to New Orleans?</p> - -<p>Even if twenty whites were eager to go where now there is but one -reluctant pioneer, we should still have but a halting development on -account of the scarcity of labor. When, three hundred years ago, the -Isthmus of Panama stood in his way, Gomara wrote to his king: “There are -mountains, but there are also hands,†as if men could be conjured up -from the tropical jungle. From that day to this the scarcity of labor -has been the chief difficulty in the lowland regions of tropical South -America. Even when medicine shall have been advanced to the point where -residence in the tropics can be made safe, the Amazon basin will lack an -adequate supply of workmen. Where Humboldt saw thriving cities, the -population is still less than one to the square mile in an area as large -as fifteen of our Mississippi Valley states. We hear much about a rich -soil and little about intolerable insects; the climate favors a good -growth of vegetation, but a man can starve in a tropical forest as -easily as in a desert; certain tributaries of the Negro are bordered by -rich rubber forests, yet not a single Indian hut may be found along -their banks. Will men of the white race dig up the rank vegetation, -sleep in grass hammocks, live in the hot and humid air, or will they -stay in the cooler regions of the north and south? Will they rear -children in the temperate zones, or bury them in the tropics?</p> - -<p>What Gorgas did for Panama was done for intelligent people. Can it be -duplicated in the case of ignorant and stupid laborers? Shall the white -man with wits fight it out with Nature in a tropical forest, or fight it -out with his equals under better skies?</p> - -<p>The tropics must be won by strong hands of the lowlier classes who are -ignorant or careless of hygiene, and not by the khaki-clad robust young -men like those who work at Panama. Tropical medicine can do something -for these folk, but it cannot do much. And we cannot surround every -laborer’s cottage with expensive screens, oiled ditches, and well-kept -lawns. There is a practical optimism and a sentimental optimism. The one -is based on facts;<a name="page_035" id="page_035"></a> the other on assumptions. It is pleasant to think -that the tropical forest may be conquered. It is nonsense to say that we -are now conquering it in any comprehensive and permanent way. That sort -of conquest is still a dream, as when Humboldt wrote over a hundred -years ago.<a name="page_036" id="page_036"></a></p> - -<h3><a name="CHAPTER_IV" id="CHAPTER_IV"></a>CHAPTER IV<br /><br /> -THE FOREST INDIANS</h3> - -<p>T<small>HE</small> people of a tropical forest live under conditions not unlike those -of the desert. The Sahara contains 2,000,000 persons within its borders, -a density of one-half to the square mile. This is almost precisely the -density of population of a tract of equivalent size in the lowland -forests of South America. Like the oases groups in the desert of aridity -are the scattered groups along the river margins of the forest. The -desert trails run from spring to spring or along a valley floor where -there is seepage or an intermittent stream; the rivers are the highways -of the forest, the flowing roads, and away from them one is lost in as -true a sense as one may be lost in the desert.</p> - -<p>A man may easily starve in the tropical forest. Before starting on even -a short journey of two or three days a forest Indian stocks his canoe -with sugar cane and yuca and a little parched corn. He knows the -settlements as well as his desert brother knows the springs. The Pahute -Indian of Utah lives in the irrigated valleys and makes annual -excursions across the desert to the distant mountains to gather the -seeds of the nut pine. The Machiganga lives in the hills above the -Urubamba and annually comes down through the forest to the river to fish -during the dry season.</p> - -<p>The Machigangas are one of the important tribes of the Amazon basin. -Though they are dispersed to some extent upon the plains their chief -groups are scattered through the heads of a large number of valleys near -the eastern border of the Andes. Chief among the valleys they occupy are -the Pilcopata, Tono, Piñi-piñi, Yavero, Yuyato, Shirineiri, Ticumpinea, -Timpia, and Camisea (<a href="#fig_203">Fig. 203</a>). In their distribution, in their -relations with each other, in their manner of life, and to some extent -in their personal traits, they display characteristics strikingly like -those<a name="page_037" id="page_037"></a> seen in desert peoples. Though the forest that surrounds them -suggests plenty and the rivers the possibility of free movement with -easy intercourse, the struggle of life, as in the desert, is against -useless things. Travel in the desert is a conflict with heat and -aridity; but travel in the tropic forest is a struggle against space, -heat, and a superabundant and all but useless vegetation.</p> - -<p>The Machigangas are one of the subtribes of the Campas Indians, one of -the most numerous groups in the Amazon Valley. It is estimated that -there are in all about 14,000 to 16,000 of them. Each subtribe numbers -from one to four thousand, and the territory they occupy extends from -the limits of the last plantations—for example, Rosalina in the -Urubamba Valley—downstream beyond the edge of the plains. Among them -three subtribes are still hostile to the whites: the Cashibos, the -Chonta Campas, and the Campas Bravos.</p> - -<p>In certain cases the Cashibos are said to be anthropophagous, in the -belief that they will assume the strength and intellect of those they -eat. This group is also continuously at war with its neighbors, goes -naked, uses stone hatchets, as in ages past, because of its isolation -and unfriendliness, and defends the entrances to the tribal huts with -dart and traps. The Cashibos are diminishing in numbers and are now -scattered through the valley of the Gran Pajonal, the left bank of the -Pachitea, and the Pampa del Sacramento.<a name="FNanchor_2_2" id="FNanchor_2_2"></a><a href="#Footnote_2_2" class="fnanchor">[2]</a></p> - -<p>The friendliest tribes live in the higher valley heads, where they have -constant communication with the whites. The use of the bow and arrow has -not, however, been discontinued among them, in spite of the wide -introduction of the old-fashioned muzzle-loading shotgun, which they -prize much more highly than the latest rifle or breech-loading shotgun -because of its simplicity and cheapness.<a name="page_038" id="page_038"></a> Accidents are frequent among -them owing to the careless use of fire-arms. On our last day’s journey -on the Urubamba above the mouth of the Timpia one of our Indian boys -dropped his canoe pole on the hammer of a loaded shotgun, and not only -shot his own fingers to pieces, but gravely wounded his father (<a href="#fig_2">Fig. 2</a>). -In spite of his suffering the old chief directed our work at the canoe -and even was able to tell us the location of the most favorable channel. -Though the night that followed was as black as ink, with even the stars -obscured by a rising storm, his directions never failed. We poled our -way up five long rapids without special difficulties, now working into -the lee of a rock whose location he knew within a few yards, now -paddling furiously across the channel to catch the upstream current of -an eddy.</p> - -<p>The principal groups of Machigangas live in the middle Urubamba and its -tributaries, the Yavero, Yuyato, Shirineiri, Ticumpinea, Timpia, -Pachitea, and others. There is a marked difference in the use of the -land and the mode of life among the different groups of this subtribe. -Those who live in the lower plains and river “playas,†as the patches of -flood plain are called, have a single permanent dwelling and alternately -fish and hunt. Those that live on hill farms have temporary reed huts on -the nearest sandbars and spend the best months of the dry season—April -to October—in fishing and drying fish to be carried to their mountain -homes (<a href="#fig_21">Fig. 21</a>). Some families even duplicate <i>chacras</i> or farms at the -river bank and grow yuca and sugar cane. In latter years smallpox, -malaria, and the rubber hunters have destroyed many of the river -villages and driven the Indians to permanent residence in the hills or, -where raids occur, along secret trails to hidden camps.</p> - -<p>Their system of agriculture is strikingly adapted to some important -features of tropical soil. The thin hillside soils of the region are but -poorly stocked with humus, even in their virgin condition. Fallen trees -and foliage decay so quickly that the layer of forest mold is -exceedingly thin and the little that is incorporated in the soil is -confined to a shallow surface layer. To meet these special conditions -the Indian makes new clearings by girdling<a name="page_039" id="page_039"></a> and burning the trees. When -the soil becomes worn out and the crops diminish, the old clearing is -abandoned and allowed to revert to natural growth and a new farm is -planted to corn and yuca. The population is so scattered and thin that -the land assignment system current among the plateau Indians is not -practised among the Machigangas. Several families commonly live together -and may be separated from their nearest neighbors by many miles of -forested mountains. The land is free for all, and, though some heavy -labor is necessary to clear it, once a small patch is cleared it is easy -to extend the tract by limited annual cuttings. Local tracts of -naturally unforested land are rarely planted, chiefly because the -absence of shade has allowed the sun to burn out the limited humus -supply and to prevent more from accumulating. The best soil of the -mountain slopes is found where there is the heaviest growth of timber, -the deepest shade, the most humus, and good natural drainage. It is the -same on the playas along the river; the recent additions to the flood -plain are easy to cultivate, but they lack humus and a fine matrix which -retains moisture and prevents drought or at least physiologic dryness. -Here, too, the timbered areas or the cane swamps are always selected for -planting.</p> - -<p>The traditions of the Machigangas go back to the time of the Inca -conquest, when the forest Indians, the “Antis,†were subjugated and -compelled to pay tribute.<a name="FNanchor_3_3" id="FNanchor_3_3"></a><a href="#Footnote_3_3" class="fnanchor">[3]</a> When the Inca family itself fled from Cuzco -after the Spanish Conquest and sought refuge in the wilderness it was to -the Machiganga country that they came by way of the Vilcabamba and -Pampaconas Valleys. Afterward came the Spaniards and though they did not -exercise governmental authority<a name="page_040" id="page_040"></a> over the forest Indians they had close -relations with them. Land grants were made to white pioneers for special -services or through sale and with the land often went the right to -exploit the people on it. Some of the concessions were owned by people -who for generations knew nothing save by hearsay of the Indians who -dwelt in the great forests of the valleys. In later years they have been -exploring their lands and establishing so-called relations whereby the -savage “buys†a dollar’s worth of powder or knives for whatever number -of dollars’ worth of rubber the owner may care to extract from him.</p> - -<p>The forest Indian is still master of his lands throughout most of the -Machiganga country. He is cruelly enslaved at the rubber posts, held by -the loose bonds of a desultory trade at others, and in a few places, as -at Pongo do Mainique, gives service for both love and profit, but in -many places it is impossible to establish control or influence. The -lowland Indian never falls into the abject condition of his Quechua -brother on the plateau. He is self-reliant, proud, and independent. He -neither cringes before a white nor looks up to him as a superior being. -I was greatly impressed by the bearing of the first of the forest tribes -I met in August, 1911, at Santo Anato. I had built a brisk fire and was -enjoying its comfort when La Sama returned with some Indians whom he had -secured to clear his playa. The tallest of the lot, wearing a colored -band of deer skin around his thick hair and a gaudy bunch of yellow -feathers down his back, came up, looked me squarely in the eye, and -asked</p> - -<p>“Tatiry payta?†(What is your name?)</p> - -<p>When I replied he quietly sat down by the fire, helping himself to the -roasted corn I had prepared in the hot ashes. A few days later when we -came to the head of a rapid I was busy sketching-in my topographic map -and did not hear his twice repeated request to leave the boat while the -party reconnoitered the rapid. Watching his opportunity he came -alongside from the rear—he was steersman—and, turning just as he was -leaving the boat, gave me a whack in the forehead with his open palm. La -Sama saw the motion and protested. The surly answer was:<a name="page_041" id="page_041"></a></p> - -<p>“I twice asked him to get out and he didn’t move. What does he think we -run the canoe to the bank for?â€</p> - -<p>To him the making of a map was inexplicable; I was merely a stupid white -person who didn’t know enough to get out of a canoe when told!</p> - -<p>The plateau Indian has been kicked about so long that all his -independence has been destroyed. His goods have been stolen, his -services demanded without recompense, in many places he has no right to -land, and his few real rights are abused beyond belief. The difference -between him and the forest Indian is due quite largely to differences of -environment. The plateau Indian is agricultural, the forest Indian -nomadic and in a hunting stage of development; the unforested plateau -offers no means for concealment of person or property, the forest offers -hidden and difficult paths, easy means for concealment, for ambush, and -for wide dispersal of an afflicted tribe. The brutal white of the -plateau follows altogether different methods when he finds himself in -the Indian country, far from military assistance, surrounded by fearless -savages. He may cheat but he does not steal, and his brutality is always -carefully suited to both time and place.</p> - -<p>The Machigangas are now confined to the forest, but the limits of their -territory were once farther upstream, where they were in frequent -conflict with the plateau Indians. As late as 1835, according to General -Miller,<a name="FNanchor_4_4" id="FNanchor_4_4"></a><a href="#Footnote_4_4" class="fnanchor">[4]</a> they occupied the land as far upstream as the “Encuentro†-(junction) of the Urubamba and the Yanatili (<a href="#fig_53">Fig. 53</a>). Miller likewise -notes that the Chuntaguirus, “a superior race of Indians†who lived -“toward the Marañon,†came up the river “200 leagues†to barter with the -people thereabouts.</p> - -<p>“They bring parrots and other birds, monkeys, cotton robes white and -painted, wax balsams, feet of the gran bestia, feather ornaments for the -head, and tiger and other skins, which they exchange for hatchets, -knives, scissors, needles, buttons, and any sort of glittering bauble.<a name="page_042" id="page_042"></a>â€</p> - -<p>On their yearly excursions they traveled in a band numbering from 200 to -300, since at the mouth of the Paucartambo (Yavero) they were generally -set upon by the Pucapacures. The journey upstream required three months; -with the current they returned home in fifteen days.</p> - -<p>Their place of meeting at the mouth of the Yanatili was a response to a -long strip of grassland that extends down the deep and dry Urubamba -Valley, as shown in Figs. 53-B and 55. The wet forests, in which the -Machigangas live, cover the hills back of the valley plantations; the -belt of dry grassland terminates far within the general limits of the -red man’s domain and only 2,000 feet above the sea. It is in this strip -of low grassland that on the one hand the highland and valley dwellers, -and on the other the Indians of the hot forested valleys and the -adjacent lowland found a convenient place for barter. The same -physiographic features are repeated in adjacent valleys of large size -that drain the eastern aspect of the Peruvian Andes, and in each case -they have given rise to the periodic excursions of the trader.</p> - -<p>These annual journeys are no longer made. The planters have crept down -valley. The two best playas below Rosalina are now being cleared. Only a -little space remains between the lowest valley plantations and the -highest rubber stations. Furthermore, the Indians have been enslaved by -the rubber men from the Ucayali. The Machigangas, many of whom are -runaway peons, will no longer take cargoes down valley for fear of -recapture. They have the cautious spirit of fugitives except in their -remote valleys. There they are secure and now and then reassert their -old spirit when a lawless trader tries to browbeat them into an -unprofitable trade. Also, they are yielding to the alluring call of the -planter. At Santo Anato they are clearing a playa in exchange for -ammunition, machetes, brandy, and baubles. They no longer make annual -excursions to get these things. They have only to call at the nearest -plantation. There is always a wolf before the door of the planter—the -lack of labor. Yet, as on every frontier, he turns wolf himself when the -lambs come, and without shame takes a week’s work for a penny mirror, -or, worse still, supplies them<a name="page_043" id="page_043"></a> with firewater, for that will surely -bring them back to him. Since this is expensive they return to their -tribal haunts with nothing except a debauched spirit and an appetite -from which they cannot run away as they did from their task masters in -the rubber forest. Hence the vicious circle: more brandy, more labor; -more labor, more cleared land; more cleared land, more brandy; more -brandy, less Indian. But by that time the planter has a large sugar -estate. Then he can begin to buy the more expensive plateau labor, and -in turn debauch it.</p> - -<p>Nature as well as man works against the scattered tribes of Machigangas -and their forest kinsmen. Their country is exceedingly broken by -ramifying mountain spurs and valleys overhung with cliffs or bordered by -bold, wet, fern-clad slopes. It is useless to try to cut your way by a -direct route from one point to another. The country is mantled with -heavy forest. You must follow the valleys, the ancient trails of the -people. The larger valleys offer smooth sand-bars along the border of -which canoes may be towed upstream, and there are little cultivated -places for camps. But only a few of the tribes live along them, for they -are also more accessible to the rubbermen. The smaller valleys, -difficult of access, are more secure and there the tribal remnants live -today. While the broken country thus offers a refuge to fugitive bands -it is the broken country and its forest cover that combine to break up -the population into small groups and keep them in an isolated and -quarrelsome state. Chronic quarreling is not only the product of mere -lack of contact. It is due to many causes, among which is a union of the -habit of migration and divergent tribal speech. Every tribe has its own -peculiar words in addition to those common to the group of tribes to -which it belongs. Moreover each group of a tribe has its distinctive -words. I have seen and used carefully prepared vocabularies—no two of -which are alike throughout. They serve for communication with only a -limited number of families. These peculiarities increase as experiences -vary and new situations call for additions to or changes in their -vocabularies, and when migrating tribes meet their speech may be so -unlike as to make communication difficult.<a name="page_044" id="page_044"></a> Thus arise suspicion, -misunderstanding, plunder, and chronic war. Had they been a united -people their defense of their rough country might have been successful. -The tribes have been divided and now and again, to get firearms and -ammunition with which to raid a neighbor, a tribe has joined its -fortunes to those of vagrant rubber pickers only to find in time that -its women were debased, its members decimated by strange and deadly -diseases, and its old morality undermined by an insatiable desire for -strong drink.<a name="FNanchor_5_5" id="FNanchor_5_5"></a><a href="#Footnote_5_5" class="fnanchor">[5]</a> The Indian loses whether with the white or against him.</p> - -<p>The forest Indian is held by his environment no less strongly than the -plateau Indian. We hear much about the restriction of the plateau -dweller to the cool zone in which the llama may live. As a matter of -fact he lives far below the cool zone, where he no longer depends upon -the llama but rather upon the mule for transport. The limits of his -range correspond to the limits of the grasslands in the dry valley -pockets already described (p. <a href="#page_042">42</a>), or on the drier mountain slopes below -the zone of heaviest rainfall (<a href="#fig_54">Fig. 54</a>). It is this distribution that -brought him into such intimate contact with the forest Indian. The old -and dilapidated coca terraces of the Quechuas above the Yanatili almost -overlook the forest patches where the Machigangas for centuries built -their rude huts. A good deal has been written about the attempts of the -Incas to extend their rule into this forest zone and about the failure -of these attempts on account of the tropical climate. But the forest -Indian was held by bonds equally secure. The cold climate of the plateau -repelled him as it does today. His haunts are the hot valleys where he -need wear only a wild-cotton shirt or where he may go naked altogether. -That he raided the lands of the plateau Indian is certain, but he could -never displace him. Only along the common borders of their domains, -where the climates of two zones merged into each other, could the forest -Indian and the plateau Indian seriously dispute each other<a name="page_045" id="page_045"></a>’s claims to -the land. Here was endless conflict but only feeble trade and only the -most minute exchanges of cultural elements.</p> - -<p>Even had they been as brothers they would have had little incentive to -borrow cultural elements from each other. The forest dweller requires -bow and arrow; the plateau dweller requires a hoe. There are fish in the -warm river shallows of the forested zone; llamas, vicuña, vizcachas, -etc., are a partial source of food supply on the plateau. Coca and -potatoes are the chief products of the grassy mountain slopes; yuca, -corn, bananas, are the chief vegetable foods grown on the tiny -cultivated patches in the forest. The plateau dweller builds a -thick-walled hut; the valley dweller a cane shack. So unlike are the two -environments that it would be strange if there had been a mixture of -racial types and cultures. The slight exchanges that were made seem -little more than accidental. Even today the Machigangas who live on the -highest slopes own a few pigs obtained from Quechuas, but they never eat -their flesh; they keep them for pets merely. I saw not a single woolen -article among the Indians along the Urubamba whereas Quechuas with -woolen clothing were going back and forth regularly. Their baubles were -of foreign make; likewise their few hoes, likewise their guns.</p> - -<p>They clear the forest about a mid-cotton tree and spin and weave the -cotton fiber into sacks, cords for climbing trees when they wish to -chase a monkey, ropes for hauling their canoes, shirts for the married -men and women, colored head-bands, and fish nets. The slender strong -bamboo is gathered for arrows. The chunta palm, like bone for hardness, -supplies them with bows and arrow heads. The brilliant red and yellow -feathers of forest birds, also monkey bones and teeth, are their natural -ornaments. Their life is absolutely distinct from that of their Quechua -neighbors. Little wonder that for centuries forest and plateau Indians -have been enemies and that their cultures are so distinct, for their -environment everywhere calls for unlike modes of existence and distinct -cultural development.<a name="page_046" id="page_046"></a></p> - -<h3><a name="CHAPTER_V" id="CHAPTER_V"></a>CHAPTER V<br /><br /> -THE COUNTRY OF THE SHEPHERDS</h3> - -<p>T<small>HE</small> lofty mountain zones of Peru, the high bordering valleys, and the -belts of rolling plateau between are occupied by tribes of shepherds. In -that cold, inhospitable region at the top of the country are the highest -permanent habitations in the world—17,100 feet (5,210 m.)—the loftiest -pastures, the greatest degree of adaptation to combined altitude and -frost. It is here only a step from Greenland to Arcady. Nevertheless it -is Greenland that has the people. Why do they shun Arcady? To the -traveler from the highlands the fertile valleys between 5,000 and 8,000 -feet (1,500 to 2,500 m.) seem like the abode of friendly spirits to -whose charm the highland dweller must yield. Every pack-train from -valley to highland carries luxury in the form of fruit, coca, cacao, and -sugar. One would think that every importation of valley products would -be followed by a wave of migration from highland to valley. On the -contrary the highland people have clung to their lofty pastures for -unnumbered centuries. Until the Conquest the last outposts of the Incas -toward the east were the grassy ridges that terminate a few thousand -feet below the timber line.</p> - -<p>In this natural grouping of the people where does choice or blind -prejudice or instinct leave off? Where does necessity begin? There are -answers to most of these questions to be found in the broad field of -geographic comparison. But before we begin comparisons we must study the -individual facts upon which they rest. These facts are of almost every -conceivable variety. They range in importance from a humble shepherd’s -stone corral on a mountain slope to a thickly settled mountain basin. -Their interpretation is to be sought now in the soil of rich playa -lands, now in the fixed climatic zones and rugged relief of deeply -dissected, lofty highlands in the tropics. Some of the controlling -factors are historical, others economic; still other factors have<a name="page_047" id="page_047"></a> -exerted their influence through obscure psychologic channels almost -impossible to trace. The <i>why</i> of man’s distribution over the earth is -one of the most complicated problems in natural science, and the -solution of it is the chief problem of the modern geographer.</p> - -<p>At first sight the mountain people of the Peruvian Andes seem to be -uniform in character and in mode of life. The traveler’s first -impression is that the same stone-walled, straw-thatched type of hut is -to be found everywhere, the same semi-nomadic life, the same degrees of -poverty and filth. Yet after a little study the diversity of their lives -is seen to be, if not a dominating fact, at least one of surprising -importance. Side by side with this diversity there runs a corresponding -diversity of relations to their physical environment. Nowhere else on -the earth are greater physical contrasts compressed within such small -spaces. If, therefore, we accept the fundamental theory of geography -that there is a general, necessary, varied, and complex relation between -man and the earth, that theory ought here to find a really vast number -of illustrations. A glance at the accompanying figures discloses the -wide range of relief in the Peruvian Andes. The corresponding range in -climate and in life therefore furnishes an ample field for the -application of the laws of human distribution.</p> - -<p>In analyzing the facts of distribution we shall do well to begin with -the causes and effects of migration. Primitive man is in no small degree -a wanderer. His small resources often require him to explore large -tracts. As population increases the food quest becomes more intense, and -thus there come about repeated emigrations which increase the food -supply, extend its variety, and draw the pioneers at last into contact -with neighboring groups. The farther back we go in the history of the -race the clearer it becomes that migrations lie at the root of much of -human development. The raid for plunder, women, food, beasts, is a -persistent feature of the life of those primitive men who live on the -border of unlike regions.</p> - -<p>The shepherd of the highland and the forest hunter of the plains -perforce range over vast tracts, and each brings back to the<a name="page_048" id="page_048"></a> home group -news that confirms the tribal choice of habitation or sets it in motion -toward a more desirable place. Superstitions may lead to flight akin to -migration. Epidemics may be interpreted as the work of a malignant -spirit from which men must flee. War may drive a defeated group into the -fastnesses of a mountain forest where pursuit by stream or trail weakens -the pursuer and confines his action, thereby limiting his power. Floods -may come and destroy the cultivated spots. Want or mere desire in a -hundred forms may lead to movement.</p> - -<p>Even among forest tribes long stationary the facile canoe and the light -household necessities may easily enable trivial causes to develop the -spirit of restlessness. Pressure of population is a powerful but not a -general cause of movement. It may affect the settled groups of the -desert oases, or the dense population of fertile plains that is rooted -in the soil. On the other hand mere whims may start a nomadic group -toward a new goal. Often the goal is elusive and the tribe turns back to -the old haunts or perishes in the shock of unexpected conflict.</p> - -<p>In the case of both primitive societies and those of a higher order the -causes and the results of migration are often contradictory. These will -depend on the state of civilization and the extremes of circumstance. -When the desert blooms the farmer of the Piura Valley in northwestern -Peru turns shepherd and drives his flocks of sheep and goats out into -the short-lived pastures of the great pampa on the west. In dry years he -sends them eastward into the mountains. The forest Indian of the lower -Urubamba is a fisherman while the river is low and lives in a reed hut -beside his cultivated patch of cane and yuca. When the floods come he is -driven to the higher ground in the hills where he has another cultivated -patch of land and a rude shelter. To be sure, these are seasonal -migrations, yet through them the country becomes better known to each -new generation of men. And each generation supplies its pioneers, who -drift into the remoter places where population is scarce or altogether -wanting.</p> - -<p><a name="fig_24" id="fig_24"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_048a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_048a_sml.jpg" width="330" height="214" alt="Fig. 24—This stone hut, grass-thatched, is the highest -permanent habitation in Peru, and is believed to be the highest in the -world. Altitude of 17,100 feet (5,210 m.) determined by instrumental -survey. The general geographic relationships of the region in which the -hut is situated are shown in Fig. 25. For location see the topographic -map, Fig. 204." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 24—This stone hut, grass-thatched, is the highest -permanent habitation in Peru, and is believed to be the highest in the -world. Altitude of 17,100 feet (5,210 m.) determined by instrumental -survey. The general geographic relationships of the region in which the -hut is situated are shown in <a href="#fig_25">Fig. 25</a>. For location see the topographic -map, <a href="#fig_204">204</a> .</p> -</div> - -<p>Dry years and extremely dry years may have opposite effects. When -moderate dryness prevails the results may be endurable.<a name="page_049" id="page_049"></a> The oases -become crowded with men and beasts just when they can ill afford to -support them. The alfalfa meadows become overstocked and cattle become -lean and almost worthless. But there is at least bare subsistence. By -contrast, if extreme and prolonged drought prevails, some of the people -are driven forth to more favored spots. At Vallenar in central Chile -some of the workmen in extreme years go up to the nitrate pampa; in wet -years they return. When the agents of the nitrate companies hear of hard -times in a desert valley they offer employment to the stricken people. -It not infrequently happens that when there are droughts in desert Chile -there are abundant rains in Argentina on the other side of the -Cordillera. There has therefore been for many generations an irregular -and slight, though definite, shifting of population from one side of the -mountains to the other as periods of drought and periods of rain -alternated in the two regions. Some think there is satisfactory evidence -to prove that a number of the great Mongolian emigrations took place in -wet years when pasture was abundant and when the pastoral nomad found it -easy to travel. On the other hand it has been urged that the cause of -many emigrations was prolonged periods of drought when the choice lay -between starvation and flight. It is evident from the foregoing that -both views may be correct in spite of the fact that identical effects -are attributed to opposite causes.</p> - -<p><a name="fig_25" id="fig_25"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_050_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_050_sml.jpg" width="215" height="258" alt="Fig. 25—Regional diagram for the Maritime Cordillera to -show the physical relations in the district where the highest habitation -in the world are located. For location, see Fig. 20. It should be -remembered that the orientation of these diagrams is generalized. By -reference to Fig. 20 it will be seen that some portions of the crest of -the Maritime Cordillera run east and west and others north and south. -The same is true of the Cordillera Vilcapampa, Fig. 36." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 25—Regional diagram for the Maritime Cordillera to -show the physical relations in the district where the highest habitation -in the world are located. For location, see Fig. <a href="#fig_20">20</a>. It should be -remembered that the orientation of these diagrams is generalized. By -reference to <a href="#fig_20">20</a> it will be seen that some portions of the crest of -the Maritime Cordillera run east and west and others north and south. -The same is true of the Cordillera Vilcapampa, <a href="#fig_36">Fig. 36</a>.</p> -</div> - -<div class="blockquot"><p><i>Note on regional diagrams.</i>—For the sake of clearness I have -classified the accompanying facts of human distribution in the -country of the shepherds and represented them graphically in -“regional†diagrams, Figs. 17, 25, 26, 32, 34, 36, 42, 65. These -diagrams are constructed on the principle of dominant control. Each -brings out the factors of greatest importance in the distribution -of the people in a given region. Furthermore, the facts are -compressed within the limits of a small rectangle. This -compression, though great, respects all essential relations. For -example, every location on these diagrams has a concrete -illustration but the accidental relations of the field have been -omitted; the essential relations are preserved. Each diagram is, -therefore, a kind of generalized type map. It bears somewhat the -same relation to the facts of human geography that a block diagram -does to physiography. The darkest shading represents steep -snow-covered country; the next lower grade represents rough but -snow-free country; the lightest shading represents moderate relief; -unshaded parts represent plain or plateau. Small circles represent -forest or woodland; small open-spaced dots, grassland. Fine -alluvium is represented by small closely spaced dots; coarse -alluvium by large closely spaced dots.</p> - -<p>To take an illustration. In Figure 32 we have the Apurimac region -near Pasaje (see location map, <a href="#fig_20">20</a> ). At the lower edge of the -rectangle is a snow-capped outlier of the Cordillera Vilcapampa. -The belt of rugged country represents the lofty, steep, exposed, -and largely inaccessible ridges at the mid-elevations of the -mountains below the glaciated slopes at the heads of tributary -valleys. The villages in the belt of pasture might well be -Incahuasi and Corralpata. The floors of the large canyons on either -hand are bordered by extensive alluvial fans. The river courses are -sketched in a diagrammatic way only, but a map would not be -different in its general disposition. Each location is justified by -a real place with the same essential features and relations. In -making the change there has been no alteration of the general -relation of the alluvial lands to each other or to the highland. By -suppressing unnecessary details there is produced a diagram whose -essentials have simple and clear relations. When such a regional -diagram is amplified by photographs of real conditions it becomes a -sort of generalized picture of a large group of geographic facts. -One could very well extend the method to the whole of South -America. It would be a real service to geography to draw up a set -of, say, twelve to fifteen regional diagrams, still further -generalized, for the whole of the continent. As a broad -classification they would serve both the specialist and the general -student. As the basis for a regional map of South America they -would be invaluable if worked out in sufficient detail and -constructed on the indispensable basis of field studies.</p></div> - -<p>It is still an open question whether security or insecurity is more -favorable for the broad distribution of the Peruvian Indians of the -mountain zone which forms the subject of this chapter. Certainly both -tend to make the remoter places better known. Tradition has it that, in -the days of intertribal conflict before the Conquest, fugitives fled -into the high mountain pastures and lived in hidden places and in caves. -Life was insecure and relief was sought in flight. On the other hand -peace has brought security to life. The trails are now safe. A shepherd -may drive his flock anywhere. He no longer has any one to fear in his -search for new pastures. It would perhaps be safe to conclude that there -is equally broad distribution of men in the mountain pastures in time of -peace and in time of war. There is, however, a difference in<a name="page_050" id="page_050"></a> the kind -of distribution. In time of peace the individual is safe anywhere; in -time of unrest he is safe only when isolated and virtually concealed. By -contrast, the group living near the trails is<a name="page_051" id="page_051"></a> scattered by plundering -bands and war parties. The remote and isolated group may successfully -oppose the smaller band and the individuals that might reach the remoter -regions. The fugitive group would have nothing to fear from large bands, -for the limited food supply would inevitably cause these to disintegrate -upon leaving the main routes of travel. Probably the fullest exploration -of the mountain pastures has resulted from the alternation of peace and -war. The opposite conditions which these establish foster both kinds of -distribution; hence both the remote group life encouraged by war and the -individual’s lack of restraint in<a name="page_052" id="page_052"></a> time of peace are probably in large -part responsible for the present widespread occupation of the Peruvian -mountains.</p> - -<p>The loftiest habitation in the world (<a href="#fig_24">Fig. 24</a>) is in Peru. Between -Antabamba and Cotahuasi occur the highest passes in the Maritime -Cordillera. We crossed at 17,400 feet (5,300 m.), and three hundred feet -lower is the last outpost of the Indian shepherds. The snowline, very -steeply canted away from the sun, is between 17,200 and 17,600 feet -(5,240 to 5,360 m.). At frequent intervals during the three months of -winter, snowfalls during the night and terrific hailstorms in the late -afternoon drive both shepherds and flocks to the shelter of leeward -slopes or steep canyon walls. At our six camps, between 16,000 and -17,200 feet (4,876 and 5,240 m.), in September, 1911, the minimum -temperature ranged from 4° to 20°F. The thatched stone hut that we -passed at 17,100 feet and that enjoys the distinction of being the -highest in the world was in other respects the same as the thousands of -others in the same region. It sheltered a family of five. As we passed, -three rosy-cheeked children almost as fat as the sheep about them were -sitting on the ground in a corner of the corral playing with balls of -wool. Hundreds of alpacas and sheep grazed on the hill slopes and valley -floor, and their tracks showed plainly that they were frequently driven -up to the snowline in those valleys where a trickle of water supported a -band of pasture. Less than a hundred feet below them were other huts and -flocks.</p> - -<p>Here we have the limits of altitude and the limits of resources. The -intervalley spaces do not support grass. Some of them are quite bare, -others are covered with mosses. It is too high for even the tola -bush—that pioneer of Alpine vegetation in the Andes. The distance<a name="FNanchor_6_6" id="FNanchor_6_6"></a><a href="#Footnote_6_6" class="fnanchor">[6]</a> to -Cotahuasi is 75 miles (120 km.), to Antabamba 50 miles (80 km.). Thence -wool must be shipped by pack-train to the railroad in the one case 250 -miles (400 km.) to Arequipa, in the other case 200 miles (320 km.) to -Cuzco. Even the potatoes and barley, which must be imported, come from -valleys several days’ journey away. The question naturally arises why -these people live on the rim of the world. Did they seek out these -neglected<a name="page_053" id="page_053"></a> pastures, or were they driven to them? Do they live here by -choice or of necessity? The answer to these questions introduces two -other geographic factors of prime importance, the one physical, the -other economic.</p> - -<p>The main tracts of lofty pasture above Antabamba cover mountain slopes -and valley floor alike, but the moist valley floors supply the best -grazing. Moreover, the main valleys have been intensively glaciated. -Hence, though their sides are steep walls, their floors are broad and -flat. Marshy tracts, periodically flooded, are scattered throughout, and -here and there are overdeepened portions where lakes have gathered. -There is a thick carpet of grass, also numerous huts and corrals, and -many flocks. At the upper edge of the main zone of pasture the grasses -become thin and with increasing altitude give out altogether except -along the moist valley floors or on shoulders where there is seepage.</p> - -<p>If the streams head in dry mountain slopes without snow the grassy bands -of the valley floor terminate at moderate elevations. If the streams -have their sources in snowfields or glaciers there is a more uniform -run-off, and a ribbon of pasture may extend to the snowline. To the -latter class belong the pastures that support these remote people.</p> - -<p>In the case of the Maritime Andes the great elevation of the snowline is -also a factor. If, in Figure 25, we think of the snowline as at the -upper level of the main zone of pasture then we should have the -conditions shown in Figure 36, where the limit of general, not local, -occupation is the snowline, as in the Cordillera Vilcapampa and between -Chuquibambilla and Antabamba.</p> - -<p>A third factor is the character of the soil. Large amounts of volcanic -ash and lapilli were thrown out in the late stages of volcanic eruption -in which the present cones of the Maritime Andes were formed. The coarse -texture of these deposits allows the ready escape of rainwater. The -combination of extreme aridity and great elevation results in a double -restraint upon vegetation. Outside of the moist valley floors, with -their film of ground moraine on whose surface plants find a more -congenial soil, there is an extremely small amount of pasture. Here are -the natural<a name="page_054" id="page_054"></a> grazing grounds of the fleet vicuña. They occur in -hundreds, and so remote and little disturbed are they that near the main -pass one may count them by the score. As we rode by, many of them only -stared at us without taking the trouble to get beyond rifle shot. It is -not difficult to believe that the Indians easily shoot great numbers in -remote valleys that have not been hunted for years.</p> - -<p>The extreme conditions of life existing on these lofty plateaus are well -shown by the readiness with which even the hardy shepherds avail -themselves of shelter. Wherever deep valleys bring a milder climate -within reach of the pastures the latter are unpopulated for miles on -either side. The sixty-mile stretch between Chuquibamba and Salamanca is -without even a single hut, though there are pastures superior to the -ones occupied by those loftiest huts of all. Likewise there are no -permanent homes between Salamanca and Cotahuasi, though the shepherds -migrate across the belt in the milder season of rain. Eastward and -northward toward the crest of the Maritime Cordillera there are no huts -within a day’s journey of the Cotahuasi canyon. Then there is a group of -a dozen just under the crest of the secondary range that parallels the -main chain of volcanoes. Thence northward there are a number of -scattered huts between 15,500 and 16,500 feet (4,700 and 5,000 m.), -until we reach the highest habitations of all at 17,100 feet (5,210m.).</p> - -<p><a name="fig_26" id="fig_26"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_055_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_055_sml.jpg" width="209" height="167" alt="Fig. 26—Regional diagram to show the physical relations -in the lava plateau of the Maritime Cordillera west of the continental -divide. For location, see Fig. 20. Trails lead up the intrenched -tributaries. If the irrigated bench (lower right corner) is large, a -town will be located on it. Shepherds’ huts are scattered about the edge -of the girdle of spurs. There is also a string of huts in the deep -sheltered head of each tributary. See also Fig. 29 for conditions on the -valley or canyon floor." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 26—Regional diagram to show the physical relations -in the lava plateau of the Maritime Cordillera west of the continental -divide. For location, see Fig. <a href="#fig_20">20</a>. Trails lead up the intrenched -tributaries. If the irrigated bench (lower right corner) is large, a -town will be located on it. Shepherds’ huts are scattered about the edge -of the girdle of spurs. There is also a string of huts in the deep -sheltered head of each tributary. See also <a href="#fig_29">Fig. 29</a> for conditions on the -valley or canyon floor.</p> -</div> - -<p>The unpopulated belts of lava plateau bordering the entrenched valleys -are, however, as distinctly “sustenance†spaces, to use Penck’s term, as -the irrigated and fertile alluvial fans in the bottom of the valley. -This is well shown when the rains come and flocks of llamas and sheep -are driven forth from the valleys to the best pastures. It is equally -well shown by the distribution of the shepherds’ homes. These are not -down on the warm canyon floor, separated by a half-day’s journey from -the grazing. They are in the intrenched tributary valleys of Figure 26 -or just within the rim of the canyon. It is not shelter from the cold -but from the wind that chiefly determines their location. They are also -kept near the rim of the canyon by the pressure of the farming -population<a name="page_055" id="page_055"></a> from below. Every hundred feet of descent from the arid -plateau (<a href="#fig_29">Fig. 29</a>) increases the water supply. Springs increase in number -and size; likewise belts of seepage make their appearance. The gradients -in many places diminish, and flattish spurs and shoulders interrupt the -generally steep descents of the canyon wall. Every change of this sort -has a real value to the farmer and means an enhanced price beyond the -ability of the poor shepherd to pay. If you ask a wealthy <i>hacendado</i> on -the valley floor (<a href="#fig_29">Fig. 29</a>), who it is that live in the huts above him, -he will invariably say “los Indios,†with a shrug meant to convey the -idea of poverty and worthlessness. Sometimes it is “los Indios pobres,†-or merely “los pobres.†Thus there is a vertical stratification of<a name="page_056" id="page_056"></a> -society corresponding to the superimposed strata of climate and land.</p> - -<p>At Salamanca (<a href="#fig_62">Fig. 62</a>) I saw this admirably displayed under -circumstances of unusual interest. The floor and slopes of the valley -are more completely terraced than in any other valley I know of. In the -photograph, <a href="#fig_30">30</a> , which shows at least 2,500 feet of descent near the -town, one cannot find a single patch of surface that is not under -cultivation. The valley is simply filled with people to the limit of its -capacity. Practically all are Indians, but with many grades of wealth -and importance. When we rode out of the valley before daybreak, one -September morning in 1911, there was a dead calm, and each step upward -carried us into a colder stratum of air. At sunrise we had reached a -point about 2,000 feet above the town, or 14,500 feet (4,420 m.) above -sea level. We stood on the frost line. On the opposite wall of the -valley the line was as clearly marked out as if it had been an -irrigating canal. The light was so fully reflected from the millions of -frost crystals above it that both the mountainside and the valley slopes -were sparkling like a ruffled lake at sunrise. Below the frost line the -slopes were dark or covered with yellow barley and wheat stubble or -green alfalfa.</p> - -<p>It happened that the frost line was near the line of division between -corn and potato cultivation and also near the line separating the steep -rough upper lands from the cultivable lower lands. Not a habitation was -in sight above us, except a few scattered miserable huts near broken -terraces, gullied by wet-weather streams and grown up to weeds and -brush. Below us were well-cultivated fields, and the stock was kept in -bounds by stone fences and corrals; above, the half-wild burros and -mules roamed about everywhere, and only the sheep and llamas were in -rude enclosures. Thus in a half hour we passed the frontier between the -agricultural folk below the frost line and the shepherd folk above it.</p> - -<p><a name="fig_27" id="fig_27"></a></p> -<p><a name="fig_28" id="fig_28"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_056a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_056a_sml.jpg" width="209" height="326" alt="Fig. 27—Terraced valley slopes at Huaynacotas, Cotahuasi -Valley, Peru. Elevation 11,500 feet (3,500 m.)." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 27—Terraced valley slopes at Huaynacotas, Cotahuasi -Valley, Peru. Elevation 11,500 feet (3,500 m.).</p> - -<p class="caption"><span class="smcap">Fig. 28</span>—The highly cultivated and thoroughly terraced -floor of the Ollantaytambo Valley at Ollantaytambo. This is a tributary -of the Urubamba; elevation, 11,000 feet.</p></div> - -<p><a name="fig_29" id="fig_29"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_056b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_056b_sml.jpg" width="213" height="322" alt="Fig. 29—Cotahuasi on the floor of the Cotahuasi canyon. -The even skyline of the background is on a rather even-topped lava -plateau. The terrace on the left of the town is formed on limestone, -which is overlain by lava flows. A thick deposit of terraced alluvium -may be seen on the valley floor, and it is on one of the lower terraces -that the city of Cotahuasi stands. The higher terraces are in many cases -too dry for cultivation. The canyon is nearly 7,000 feet (2,130 m.) deep -and has been cut through one hundred principal lava flows." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 29—Cotahuasi on the floor of the Cotahuasi canyon. -The even skyline of the background is on a rather even-topped lava -plateau. The terrace on the left of the town is formed on limestone, -which is overlain by lava flows. A thick deposit of terraced alluvium -may be seen on the valley floor, and it is on one of the lower terraces -that the city of Cotahuasi stands. The higher terraces are in many cases -too dry for cultivation. The canyon is nearly 7,000 feet (2,130 m.) deep -and has been cut through one hundred principal lava flows.</p> -</div> - -<p>In a few spots the line followed an irregular course, as where flatter -lands were developed at unusual elevations or where air drainage altered -the normal temperature. And at one place the<a name="page_057" id="page_057"></a> frost actually stood on -the young corn, which led us to speculate on the possibility of securing -from Salamanca a variety of maize that is more nearly resistant to light -frosts than any now grown in the United States. In the endless and -largely unconscious experimentation of these folk perched on the valley -walls a result may have been achieved ahead of that yet reached by our -professional experimenters. Certain it is that nowhere else in the world -has the potato been grown under such severe climatic conditions as in -its native land of Peru and Bolivia. The hardiest varieties lack many -qualities that we prize. They are small and bitter. But at least they -will grow where all except very few cultivated plants fail, and they are -edible. Could they not be imported into Canada to push still farther -northward the limits of cultivation? Potatoes are now grown at Forts -Good Hope and McPherson in the lower Mackenzie basin. Would not the -hardiest Peruvian varieties grow at least as far north as the -continental timber line? I believe they could be grown still farther -north. They will endure repeated frosts. They need scarcely any -cultivation. Prepared in the Peruvian manner, as <i>chuño</i>, they could be -kept all winter. Being light, the meal derived from them could be easily -packed by hunters and prospectors. An Indian will carry in a pouch -enough to last him a week. Why not use it north of the continental limit -of other cultivated plants since it is the pioneer above the frost line -on the Peruvian mountains?</p> - -<p>The relation between farmer and shepherd or herdsman grows more complex -where deeper valleys interrupt the highlands and mountains. The -accompanying sketch, <a href="#fig_32">32</a> , represents typical relations, though based -chiefly on the Apurimac canyon and its surroundings near Pasaje. First -there is the snow-clad region at the top of the country. Below it are -grassy slopes, the homes of mountain shepherds, or rugged mountain -country unsuited for grazing. Still lower there is woodland, in patches -chiefly, but with a few large continuous tracts. The shady sides of the -ravines and the mountains have the most moisture, hence bear the densest -growths. Finally, the high country terminates in a second belt of -pasture below the woodland.<a name="page_058" id="page_058"></a></p> - -<p><a name="fig_32" id="fig_32"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_058_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_058_sml.jpg" width="207" height="237" alt="Fig. 32—Regional diagram representing the deep canyoned -country west of the Eastern Cordillera in the region of the Apurimac. -For photograph see Fig. 94. For further description see note on regional -diagrams, p. 51. Numbers 1, 2, and 3 correspond in position to the same -numbers in Fig. 33." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 32—Regional diagram representing the deep canyoned -country west of the Eastern Cordillera in the region of the Apurimac. -For photograph see <a href="#fig_94">Fig. 94</a>. For further description see note on regional -diagrams, <a href="#page_051">p. 51</a>. Numbers 1, 2, and 3 correspond in position to the same -numbers in <a href="#fig_33">Fig. 33</a>.</p> -</div> - -<p><a name="fig_30" id="fig_30"></a></p> - -<p><a name="fig_31" id="fig_31"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_058b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_058b_sml.jpg" width="311" height="214" alt="Fig. 30—Terraced hill slopes near Salamanca. There is no -part of the photograph which is not covered with terraces save a few -places where bushy growths are visible or where torrents descend through -artificial canals." /></a> - -<table border="0" cellpadding="4" cellspacing="0" summary=""> -<tr valign="top"><td class="swidth"><p class="caption"><span class="smcap">Fig. 30</span>—Terraced hill slopes near Salamanca. There is no -part of the photograph which is not covered with terraces save a few -places where bushy growths are visible or where torrents descend through -artificial canals.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig. 31</span>—Alpine pastures in the mountain valley between -Chuquibambilla and Lambrama. Huge stone corrals are built on either -slope, sheltered from the night winds that blow down-valley.</p></td></tr> -</table> -</div> - -<p>Whenever streams descend from the snow or woodland country there is -water for the stock above and for irrigation on the alluvial fan below. -But the spur ends dropping off abruptly several thousand feet have a -limited area and no running streams, and the ground water is hundreds of -feet down. There is grass for stock, but there is no water. In some -places the stock is driven<a name="page_059" id="page_059"></a> back and forth every few days. In a few -places water is brought to the stock by canal from the woodland streams -above, as at Corralpata.<a name="FNanchor_7_7" id="FNanchor_7_7"></a><a href="#Footnote_7_7" class="fnanchor">[7]</a> In the same way a canal brings water to -Pasaje hacienda from a woodland strip many miles to the west. The little -canal in the figure is almost a toy construction a few inches wide and -deep and conveying only a trickle of water. Yet on it depends the -settlement at the spur end, and if it were cut the people would have to -repair it immediately or establish new homes.</p> - -<p><a name="fig_33" id="fig_33"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_059_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_059_sml.jpg" width="211" height="64" alt="Fig. 33—Valley climates of the canyoned region shown in -Fig. 32." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 33—Valley climates of the canyoned region shown in -<a href="#fig_32">Fig. 32</a>.</p> -</div> - -<p>The canal and the pasture are possible because the slopes are moderate. -They were formed in an earlier cycle of erosion when the land was lower. -They are hung midway between the rough mountain slopes above and the -steep canyon walls below (<a href="#fig_32">Fig. 32</a>). Their smooth descents and gentle -profiles are in very pleasing contrast to the rugged scenery about them. -The trails follow them easily. Where the slopes are flattest, farmers -have settled and produce good crops of corn, vegetables, and barley. -Some farmers have even developed three-and four-story farms. On an -alluvial fan in the main valley they raise sugar cane and tropical and -subtropical fruits; on the flat upper slopes they produce corn; in the -moister soil near the edge of the woodland are fields of mountain -potatoes; and the upper pastures maintain flocks of<a name="page_060" id="page_060"></a> sheep. In one -district this change takes place in a distance that may be covered in -five hours. Generally it is at least a full and hard day’s journey from -one end of the series to the other.</p> - -<p>Wherever these features are closely associated they tend to be -controlled by the planter in some deep valley thereabouts. Where they -are widely scattered the people are independent, small groups living in -places nearly inaccessible. Legally they are all under the control of -the owners of princely tracts that take in the whole country, but the -remote groups are left almost wholly to themselves. In most cases they -are supposed to sell their few commercial products to the <i>hacendado</i> -who nominally owns their land, but the administration of this -arrangement is left largely to chance. The shepherds and small farmers -near the plantation are more dependent upon the planter for supplies, -and also their wants are more varied and numerous. Hence they pay for -their better location in free labor and in produce sold at a discount.</p> - -<p>So deep are some of the main canyons, like the Apurimac and the -Cotahuasi, that their floors are arid or semi-arid. The fortunes of -Pasaje are tied to a narrow canal from the moist woodland and a tiny -brook from a hollow in the valley wall. Where the water has thus been -brought down to the arable soil of the fans there are rich plantations -and farms. Elsewhere, however, the floor is quite dry and uncultivated. -In small spots here and there is a little seepage, or a few springs, or -a mere thread of water that will not support a plantation, wherefore -there have come into existence the valley herdsmen and shepherds. Their -intimate knowledge of the moist places is their capital, quite as much -as are the cattle and sheep they own. In a sense their lands are the -neglected crumbs from the rich man’s table. So we find the shepherd from -the hills invading the valleys just as the valley farmer has invaded the -country of the shepherd.</p> - -<p><a name="fig_34" id="fig_34"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_061_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_061_sml.jpg" width="217" height="260" alt="Fig. 34—Regional diagram to show the typical physical -conditions and relations in an intermont basin in the Peruvian Andes. -The Cuzco basin (see Fig. 37) is an actual illustration; it should, -however, be emphasized that the diagram is not a “map†of that basin, -for whilst conditions there have been utilized as a basis, the -generalization has been extended to illustrate many basins." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 34—Regional diagram to show the typical physical -conditions and relations in an intermont basin in the Peruvian Andes. -The Cuzco basin (see Fig. <a href="#fig_37">37</a>) is an actual illustration; it should, -however, be emphasized that the diagram is not a “map†of that basin, -for whilst conditions there have been utilized as a basis, the -generalization has been extended to illustrate many basins.</p> -</div> - -<p>The basin type of topography calls into existence a set of relations -quite distinct from either of those we have just described. Figure 34 -represents the main facts. The rich and comparatively flat floor of the -basin supports most of the people. The alluvial fans tributary thereto -are composed of fine material on their outer<a name="page_061" id="page_061"></a> margin and of coarse stony -waste at their heads. Hence the valley farms also extend over the edges -of the fans, while only pasture or dense chaparral occupies the upper -portions. Finally<a name="page_062" id="page_062"></a> there is the steep margin of the basin where the -broad and moderate slopes of the highland break down to the floor of the -basin.</p> - -<p><a name="fig_35" id="fig_35"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_062_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_062_sml.jpg" width="211" height="71" alt="Fig. 35—Climatic cross-section showing the location of -various zones of cultivation and pasture in a typical intermont basin in -the Peruvian Andes. The thickness of the dark symbols on the right is -proportional to the amount of each staple that is produced at the -corresponding elevation. See also the regional diagram Fig. 34." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 35—Climatic cross-section showing the location of -various zones of cultivation and pasture in a typical intermont basin in -the Peruvian Andes. The thickness of the dark symbols on the right is -proportional to the amount of each staple that is produced at the -corresponding elevation. See also the regional diagram <a href="#fig_34">Fig. 34</a>.</p> -</div> - -<p>If a given basin lies at an elevation exceeding 14,000 feet (4,270 m.), -there will be no cultivation, only pasture. If at 10,000 or 11,000 feet -(3,000 or 3,350 m.), there will be grain fields below and potato fields -above (Figs. 34 and 35). If still lower, fruit will come in and finally -sugar cane and many other subtropical products, as at Abancay. Much will -also depend upon the amount of available water and the extent of the -pasture land. Thus the densely populated Cuzco basin has a vast mountain -territory tributary to it and is itself within the limits of barley and -wheat cultivation. Furthermore there are a number of smaller basins, -like the Anta basin on the north, which are dependent upon its better -markets and transportation facilities. A dominance of this kind is -self-stimulating and at last is out of all proportion to the original -differences of nature. Cuzco has also profited as the gateway to the -great northeastern valley region of the Urubamba and its big -tributaries. All of the varied products of the subtropical valleys find -their immediate market at Cuzco.</p> - -<p>The effect of this natural conspiracy of conditions has been to place -the historic city of Cuzco in a position of extraordinary importance. -Hundreds of years before the Spanish Conquest it was a center of -far-reaching influence, the home of the powerful Inca kings. From it the -strong arm of authority and conquest was extended;<a name="page_063" id="page_063"></a> to it came tribute -of grain, wool, and gold. To one accustomed to look at such great -consequences as having at least some ultimate connection with the earth, -the situation of Cuzco would be expected to have some unique features. -With the glorious past of that city in mind, no one can climb to the -surrounding heights and look down upon the fertile mountain-rimmed plain -as at an ordinary sight (<a href="#fig_37">Fig. 37</a>). The secret of those great conquests -lies not only in mind but in matter. If the rise of the Incas to power -was not related to the topography and climate of the Cuzco basin, at -least it is certain that without so broad and noble a stage the scenes -would have been enacted on a far different scale.</p> - -<p>The first Inca king and the Spanish after the Incas found here no mobile -nomadic tribes melting away at the first touch, no savages hiding in -forest fastnesses, but a well-rooted agricultural race in whose center a -large city had grown up. Without a city and a fertile tributary plain no -strong system of government could be maintained or could even arise. It -is a great advantage in ruling to have subjects that cannot move. The -agricultural Indians of the Andean valleys and basins, in contrast to -the mobile shepherd, are as fixed as the soil from which they draw their -life.</p> - -<p>The full occupation of the pasture lands about the Cuzco basin is in -direct relation to the advantages we have already enumerated. Every part -of the region feels the pressure of population. Nowhere else in the -Peruvian Andes are the limits between cultivation and grazing more -definitely drawn than here. Moreover, there is today a marked difference -between the types that inhabit highland and basin. The basin Indian is -either a debauched city dweller or, as generally, a relatively alert -farmer. The shepherds are exceedingly ignorant and live for the most -part in a manner almost as primitive as at the time of the Conquest. -They are shy and suspicious. Many of them prefer a life of isolation and -rarely go down to the town. They live on the fringe of culture. The new -elements of their life have come to them solely by accident and by what -might be called a process of ethnic seepage. The slight advances that -have been made do not happen by design, they<a name="page_064" id="page_064"></a> merely happen. Put the -highland shepherd in the basin and he would starve in competition with -the basin type. Undoubtedly he would live in the basin if he could. He -has not been driven out of the basin; he is kept out.</p> - -<p>And thus it is around the border of the Abancay basin and others like -it. Only, the Abancay basin is lower and more varied as to resources. -The Indian is here in competition with the capitalistic white planter. -He lives on the land by sufferance alone. Farther up the slopes are the -farms of the Indians and above them are the pastures of the ignorant -shepherds. Whereas the Indian farmer who raises potatoes clings chiefly -to the edge of the Cuzco basin where lie the most undesirable -agricultural lands, the Indian farmers of Abancay live on broad rolling -slopes like those near the pass northward toward Huancarama. They are -unusually prosperous, with fields so well cultivated and fenced, so -clean and productive, that they remind one somewhat of the beautiful -rolling prairies of Iowa.</p> - -<p>It remains to consider the special topographic features of the mountain -environments we are discussing, in the Vilcapampa region on the eastern -border of the Andes (<a href="#fig_36">Fig. 36</a>). The Cordillera Vilcapampa is -snow-crested, containing a number of fine white peaks like Salcantay, -Soray, and Soiroccocha (<a href="#fig_140">Fig. 140</a>). There are many small glaciers and a -few that are several miles long. There was here in glacial times a much -larger system of glaciers, which lived long enough to work great changes -in the topography. The floors of the glaciated valleys were smoothed and -broadened and their gradients flattened (Figs. 137 and 190). The side -walls were steepened and precipitous cirques were formed at the valley -heads. Also, there were built across the valleys a number of stony -morainic ridges. With all these changes there was, however, but little -effect upon the main masses of the big intervalley spurs. They remain as -before—bold, wind-swept, broken, and nearly inaccessible.</p> - -<p><a name="fig_36" id="fig_36"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_065_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_065_sml.jpg" width="210" height="279" alt="Fig. 36—Regional diagram for the Eastern Cordillera or -Cordillera Vilcapampa. Note the crowded zones on the right (east and -north) in contrast to the open succession on the left. In sheltered -places woodland extends even higher than shown. At several points -patches of it grow right under the snowline. Other patches grow on the -floors of the glaciated valley troughs." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 36—Regional diagram for the Eastern Cordillera or -Cordillera Vilcapampa. Note the crowded zones on the right (east and -north) in contrast to the open succession on the left. In sheltered -places woodland extends even higher than shown. At several points -patches of it grow right under the snowline. Other patches grow on the -floors of the glaciated valley troughs.</p> -</div> - -<p>The work of the glaciers aids the mountain people. The stony moraines -afford them handy sizable building material for their stone huts and -their numerous corrals. The thick tufts of grass<a name="page_065" id="page_065"></a> in the marshy spots in -the overdeepened parts of the valleys furnish them with grass for their -thatched roofs. And, most important<a name="page_066" id="page_066"></a> of all, the flat valley floors have -the best pasture in the whole mountain region. There is plenty of water. -There is seclusion, and, if a fence be built from one valley wall to -another as can be done with little labor, an entire section of the -valley may be inclosed. A village like Choquetira, located on a bench on -the valley side, commands an extensive view up and down the valley—an -important feature in a grazing village where the corrals cannot always -be built near the houses of the owners. Long, finger-like belts of -highland-shepherd population have thus been extended into the mountain -valleys. Sheep and llamas drift right up to the snowline.</p> - -<p>There is, however, a marked difference between the people on opposite -sides of the Cordillera Vilcapampa. On the west the mountains are -bordered by a broad highland devoted to grazing. On the east there is a -narrower grazing belt leading abruptly down to tropical valleys. The -eastern or leeward side is also the warmer and wetter side of the -Cordillera. The snowline is several hundred feet lower on the east. The -result is that patches of scrub and even a little woodland occur almost -at the snowline in favored places. Mist and storms are more frequent. -The grass is longer and fresher. Vegetation in general is more abundant. -The people make less of wool than of cattle, horses, and mules. -Vilcabamba pueblo is famous for its horses, wiry, long-haired little -beasts, as hardy as Shetland ponies. We found cattle grazing only five -hundred feet below the limit of perpetual snow. There are cultivated -spots only a little farther down, and only a thousand feet below the -snow are abandoned terraces. At the same elevation are twisted quenigo -trees, at least two hundred years old, as shown by their rings of -growth. Thus the limits of agriculture are higher on the east; likewise -the limits of cattle grazing that naturally goes with agriculture. Sheep -would thrive, but llamas do better in drier country, and the shepherd -must needs mix his flocks, for the wool which is his chief product -requires transportation and only the cheap and acclimated llama is at -the shepherd’s disposal. From these facts it will be seen that the -anthropo-geographic contrasts between the eastern and western<a name="page_067" id="page_067"></a> sides of -the Cordillera Vilcapampa are as definite as the climatic and vegetal -contrasts. This is especially well shown in the differences between dry -Arma, deep-sunk in a glaciated valley west of the crest of the -mountains, and wet Puquiura, a half-day’s journey east of the crest. -There is no group on the east at all comparable to the shepherds of -Choquetira, either in the matter of thorough-going dependence upon -grazing or in that of dependence upon glacial topography.</p> - -<p><a name="fig_37" id="fig_37"></a></p> - -<p><a name="fig_38" id="fig_38"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_066a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_066a_sml.jpg" width="212" height="324" alt="Fig. 37—Cuzco and a portion of the famous Cuzco basin -with bordering grassy highlands." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 37—Cuzco and a portion of the famous Cuzco basin -with bordering grassy highlands.</p> - -<p class="caption"><span class="smcap">Fig. 38</span>—Terraced valley slopes and floor, Urubamba -Valley between Urubamba and Ollantaytambo.</p> -</div> - -<p><a name="fig_39" id="fig_39"></a></p> - -<p><a name="fig_40" id="fig_40"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_066b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_066b_sml.jpg" width="211" height="331" alt="Fig. 39—Huichihua, near Chuquibambilla, a typical -mountain village, in the valleys of the Central Ranges, Peruvian Andes." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 39—Huichihua, near Chuquibambilla, a typical -mountain village, in the valleys of the Central Ranges, Peruvian Andes.</p> - -<p class="caption"><span class="smcap">Fig. 40</span>—Potato fluid above Vilcabamba at 12,000 feet -(3,660 m.). The natural sod is broken by a steel-shod stick and the seed -potato dropped into a mere puncture. It receives no attention thereafter -until harvest time.</p></div> - -<p>Topography is not always so intimately related to the life of the people -as here. In our own country the distribution of available water is a far -greater factor. The Peruvian Andes therefore occupy a distinctive place -in geography, since, more nearly than in most mountains, their physical -conditions have typical human relations that enable one clearly to -distinguish the limits of control of each feature of climate or relief.<a name="page_068" id="page_068"></a></p> - -<h3><a name="CHAPTER_VI" id="CHAPTER_VI"></a>CHAPTER VI<br /><br /> -THE BORDER VALLEYS OF THE EASTERN ANDES</h3> - -<p><a name="fig_41" id="fig_41"></a></p> - -<div class="figleft" style="width: 115px;"> -<a href="images/ill_page_068_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_068_sml.jpg" width="115" height="147" alt="Fig. 41—Regional diagram of the eastern aspect of the -Cordillera Vilcapampa. See also Fig. 17 of which this is an enlarged -section." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 41—Regional diagram of the eastern aspect of the -Cordillera Vilcapampa. See also <a href="#fig_17">17</a> of which this is an enlarged -section.</p> -</div> - -<p>On the northeastern border of the Peruvian Andes long mountain spurs -trail down from the regions of snow to the forested plains of the -Amazon. Here are the greatest contrasts in the physical and human -geography of the Andean Cordillera. So striking is the fact that every -serious student of Peru finds himself compelled to cross and recross -this natural frontier. The thread of an investigation runs irregularly -now into one border zone, now into another. Out of the forest came the -fierce marauders who in the early period drove back the Inca pioneers. -Down into the forest to escape from the Spaniards fled the last Inca and -his fugitive court. Here the Jesuit fathers sowed their missions along -the forest margin, and watched over them for two hundred years. From the -mountain border one rubber project after another has been launched into -the vast swampy lowlands threaded by great rivers. As an ethnic boundary -the eastern mountain border of Peru and Bolivia has no equal elsewhere -in South America. From the earliest antiquity the tribes of the -grass-covered mountains and the hordes of the forested plains have had -strongly divergent customs and speech, that bred enduring hatred and led -to frequent and bloody strife.</p> - -<p><a name="fig_42" id="fig_42"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_068a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_068a_sml.jpg" width="212" height="333" alt="Fig. 42—Rug weaver at Cotahuasi. The industry is limited -to a small group of related families, living in the Cotahuasi Canyon -near Cotahuasi. The rugs are made of alpaca wool. Pure black, pure -white, and various shades of mixed gray wool are employed. The result is -that the rugs have “fast†colors that always retain their original -contrasts. They are made only to order at the homes of the purchasers. -The money payment is small, but to it is added board and lodging, -besides tobacco, liqueurs, and wine. Before drinking they dip their -finger-tips in the wine and sprinkle the earth “that it may be -fruitful,†the air “that it may be warm,†the rug “that it may turn out -well,†and finally themselves, making the sign of the cross. Then they -set to work." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 42—Rug weaver at Cotahuasi. The industry is limited -to a small group of related families, living in the Cotahuasi Canyon -near Cotahuasi. The rugs are made of alpaca wool. Pure black, pure -white, and various shades of mixed gray wool are employed. The result is -that the rugs have “fast†colors that always retain their original -contrasts. They are made only to order at the homes of the purchasers. -The money payment is small, but to it is added board and lodging, -besides tobacco, liqueurs, and wine. Before drinking they dip their -finger-tips in the wine and sprinkle the earth “that it may be -fruitful,†the air “that it may be warm,†the rug “that it may turn out -well,†and finally themselves, making the sign of the cross. Then they -set to work.</p> -</div> - -<p><a name="fig_43" id="fig_43"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_068b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_068b_sml.jpg" width="334" height="216" alt="Fig. 43—The floor of the Urubamba Valley from Tarai. The -work of the glaciers was not confined to the lofty situations. Mountain -débris was delivered to all the streams, many of which aggraded their -floors to a depth of several hundred feet, thus increasing the extent of -arable soil at elevations where a less rigorous climate permits the -production of crops and encourages intensive cultivation." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 43—The floor of the Urubamba Valley from Tarai. The -work of the glaciers was not confined to the lofty situations. Mountain -débris was delivered to all the streams, many of which aggraded their -floors to a depth of several hundred feet, thus increasing the extent of -arable soil at elevations where a less rigorous climate permits the -production of crops and encourages intensive cultivation.</p> -</div> - -<p><a name="page_069" id="page_069"></a></p> - -<p>On the steepest spurs of the Pampaconas Valley the traveler may go from -snow to pasture in a half day and from pasture to forest in the same -time. Another day he is in the hot zone of the larger valley floors, the -home of the Machigangas. The steep descents bring out the superimposed -zones with diagrammatic simplicity. The timber line is as sharply marked -as the edge of a cultivated field. At a point just beyond the huts of -Pampaconas one may stand on a grassy spur that leads directly up—a -day’s journey—to the white summits of the Cordillera Vilcapampa. Yet so -near him is the edge of the forest that he is tempted to try to throw a -stone into it. In an hour a bitter wind from the mountains may drive him -to shelter or a cold fog come rolling up from the moist region below. It -is hard to believe that oppressive heat is felt in the valley just -beneath him.</p> - -<p>In the larger valleys the geographic contrasts are less sharp and the -transition from mountains to plain, though less spectacular, is much -more complex and scientifically interesting. The forest types -interfinger along the shady and the sunny slopes. The climate is so -varied that the forest takes on a diversified character that makes it -far more useful to man. The forest Indians and the valley planters are -in closer association. There are many islands and peninsulas of plateau -population on the valley floor. Here the zones of climate and the belts -of fertile soil have larger areas and the land therefore has greater -economic value. Much as the valley people need easier and cheaper -communication with the rest of Peru it is no exaggeration to say that -the valley products, are needed far more by the coast and plateau -peoples to make the republic self-supporting. Coca, wood, sugar, fruit, -are in such demand that their laborious and costly transportation from -the valleys to the plateau is now carried on with at least some profit -to the valley people. Improved transportation would promote travel and -friendship and supply a basis for greater political unity.</p> - -<p>A change in these conditions is imminent. Years ago the Peruvian -government decreed the construction of a railway from Cuzco to Santa Ana -and preliminary surveys were made but without<a name="page_070" id="page_070"></a> any immediate practical -effect. By June, 1914, 12.4 miles (20 km.) had been opened to traffic. -The total length of the proposed line is 112 miles (180 km.), the gauge -is to be only 2.46 feet (75 cm.),<a name="FNanchor_8_8" id="FNanchor_8_8"></a><a href="#Footnote_8_8" class="fnanchor">[8]</a> and the proposed cost several -millions of dollars. The financial problem may be solved either by a -diversion of local revenues, derived from taxes on coca and alcohol, or -by borrowed foreign capital guaranteed by local revenues.</p> - -<p>A shrubby vegetation is scattered along the valley from the village of -Urubamba, 12,000 feet (3,658 m.) above sea level, to the Canyon of -Torontoy. It is local and of little value. Trees appear at -Ollantaytambo, 11,000 feet (3,353 m.), and here too are more extensive -wheat and maize fields besides throngs of cacti and great patches of -wild geraniums. On our valley journey we camped in pleasant fields -flanked by steep hills whose summits each morning were tipped with snow. -Enormous alluvial fans have partly filled up the valleys and furnished -broad tracts of fertile soil. The patient farmers have cleared away the -stones on the flatter portions and built retaining walls for the smooth -fields required for irrigation. In places the lower valley slopes are -terraced in the most regular manner (<a href="#fig_38">Fig. 38</a>). Some of the fans are too -steep and stony for cultivation, exposing bare tracts which wash down -and cover the fields. Here and there are stone walls built especially to -retain the rush of mud and stones that the rains bring down. Many of -them were overthrown or completely buried. Unless the stream channels on -the fans are carefully watched and effective works kept up, the labor of -years may be destroyed in a single slide from the head of a steep fan.</p> - -<p>Each group of fans has a population proportioned to its size and -fertility. If there are broad expanses a town like Urubamba or a great -hacienda like Huadquiña is sure to be found. One group of huge stony -fans below Urubamba (<a href="#fig_180">Fig. 180</a>) has only a thin population, for the soil -is coarse and infertile and the rivers deeply intrenched. In some places -the tiny fans perched high upon the flanks of the mountains where little -tributaries burst out<a name="page_071" id="page_071"></a> of steep ravines are cultivated by distant owners -who also till parts of the larger fans on the main valley floors. -Between the fans of the valley bottoms and the smooth slopes of the high -plateaus are the unoccupied lands—the steep canyon walls. Only in the -most highly favored places where a small bench or a patch of alluvium -occurs may one find even an isolated dwelling. The stair-like trails, in -some places cut in solid rock, zigzag up the rocky slopes. An ascent of -a thousand feet requires about an hour’s travel with fresh beasts. The -valley people are therefore walled in. If they travel it is surely not -for pleasure. Even business trips are reduced to the smallest number. -The prosperity and happiness of the valley people are as well known -among the plateau people as is their remarkable bread. Their climate has -a combination of winter rain and winter cold with light frosts that is -as favorable for good wheat as the continuous winter cold and snow cover -of our northern Middle West. The colder grainfields of the plateau are -sowed to barley chiefly, though there is also produced some wheat. -Urubamba wheat and bread are exported in relatively large quantities, -and the market demands greater quantities than the valley can supply. -Oregon and Washington flour are imported at Cuzco, two days’ muleback -journey from the wheat fields of Urubamba.</p> - -<p>Such are the conditions in the upper Urubamba Valley. The lower valley, -beginning at Huadquiña, is 8,000 feet (2,440 m.) above sea level and -extends down to the two-thousand-foot contour at Rosalina and to one -thousand feet (305 m.) at Pongo de Mainique. The upper and lower -sections are only a score of miles (30 km.) apart between Huadquiña and -Torontoy, but there is a difference in elevation of three thousand feet -(915 m.) at just the level where the maximum contrasts are produced. The -cold timber line is at 10,500 feet (3,200 m.).<a name="FNanchor_9_9" id="FNanchor_9_9"></a><a href="#Footnote_9_9" class="fnanchor">[9]</a> Winter frosts are -common<a name="page_072" id="page_072"></a> at the one place; they are absent altogether at the other. -Torontoy produces corn; Huadquiña produces sugar cane.</p> - -<p>These contrasts are still further emphasized by the sharp topographic -break between the two unlike portions of the valley. A few miles below -Torontoy the Urubamba plunges into a mile-deep granite canyon. The walls -are so close together that it is impossible from the canyon floor to get -into one photograph the highest and steepest walls. At one place there -is over a mile of descent in a horizontal distance of 2,000 feet. Huge -granite slabs fall off along joint planes inclined but 15° from the -vertical. The effect is stupendous. The canyon floor is littered with -coarse waste and the gradient of the river greatly steepened. There is -no cultivation. The trees cling with difficulty to patches of rock waste -or to the less-inclined slopes. There is a thin crevice vegetation that -outlines the joint pattern where seepage supplies the venturesome roots -with moisture. Man has no foothold here, save at the top of the country, -as at Machu Picchu, a typical fortress location safeguarded by the -virtually inaccessible canyon wall and connected with the main ridge -slopes only by an easily guarded narrow spur. Toward the lower end of -the canyon a little finer alluvium appears and settlement begins. -Finally, after a tumble of three thousand feet over countless rapids the -river emerges at Colpani, where an enormous mass of alluvium has been -dumped. The well-intrenched river has already cut a large part of it -away. A little farther on is Huadquiña in the Salcantay Valley, where a -tributary of the Urubamba has built up a sheet of alluvial land, bright -green with cane. From the distant peaks of Salcantay and its neighbors -well-fed streams descend to fill the irrigation channels. Thus the snow -and rock-waste of the distant mountains are turned into corn and sugar -on the valley lowlands.</p> - -<p><a name="fig_44" id="fig_44"></a></p> - -<p><a name="fig_45" id="fig_45"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_072a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_072a_sml.jpg" width="216" height="327" alt="Fig. 44—The snow-capped Cordillera Vilcapampa north of -Yucay and the upper canyon of the Urubamba from the wheat fields near -Chinchero. In the foreground is one of the well-graded mature slopes of -Fig. 123. The crests of the mountains lie along the axis of a granite -intrusion. The extent of the snowfields is extraordinary in view of the -low latitude, 13° S." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 44—The snow-capped Cordillera Vilcapampa north of -Yucay and the upper canyon of the Urubamba from the wheat fields near -Chinchero. In the foreground is one of the well-graded mature slopes of -Fig. 123. The crests of the mountains lie along the axis of a granite -intrusion. The extent of the snowfields is extraordinary in view of the -low latitude, 13° S.</p> - -<p class="caption"><span class="smcap">Fig. 45</span>—Rounded slopes due to glacial action at -Pampaconas in the Pampaconas Valley near Vilcabamba. A heavy tropical -forest extends up the Pampaconas Valley to the hill slopes in the -background. Its upper limit of growth is about 10,000 feet (3,050 m.). -The camera is pointed slightly downhill.</p> -</div> - -<p><a name="fig_46" id="fig_46"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_072b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_072b_sml.jpg" width="333" height="213" alt="Fig. 46—Hacienda Huadquiña in the Salcantay Valley a -short distance above its junction with the Urubamba, elevation 8,000 -feet (2,440 m.). The cultivated fields are all planted to sugar cane. -The mountain slopes are devoted to grazing." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 46—Hacienda Huadquiña in the Salcantay Valley a -short distance above its junction with the Urubamba, elevation 8,000 -feet (2,440 m.). The cultivated fields are all planted to sugar cane. -The mountain slopes are devoted to grazing.</p> -</div> - -<p><a name="page_073" id="page_073"></a></p> - -<p>The Cordillera Vilcapampa is a climatic as well as a topographic -barrier. The southwestern aspect is dry; the northeastern aspect -forested. The gap of the canyon, it should be noticed, comes at a -critical level, for it falls just above the upper border of the zone of -maximum precipitation. The result is that though mists are driven -through the canyon by prolonged up-valley winds, they scatter on -reaching the plateau or gather high up on the flanks of the valley or -around the snowy peaks overlooking the trail between Ollantaytambo and -Urubamba. The canyon walls are drenched with rains and even some of the -lofty spurs are clothed with dense forest or scrub.</p> - -<p>Farther down the valley winds about irregularly, now pushed to one side -by a huge alluvial fan, now turned by some resistant spur of rock. -Between the front range of the Andes and the Cordillera Vilcapampa there -is a broad stretch of mountain country in the lee of the front range -which rises to 7,000 feet (2,134 m.) at Abra Tocate (<a href="#fig_15">Fig. 15</a>), and falls -off to low hills about Rosalina. It is all very rough in that there are -nowhere any flats except for the narrow playa strips along the streams. -The dense forest adds to the difficulty of movement. In general -appearance it is very much like the rugged Cascade country of Oregon -except that the Peruvian forest is much more patchy and its trees are in -many places loaded with dense dripping moss which gives the landscape a -somber touch quite absent from most of the forests of the temperate -zone.</p> - -<p>The fertility of the eastern valleys of Peru—the result of a union of -favorable climate and alluvial soil—has drawn the planter into this -remote section of the country, but how can he dispose of his products? -Even today with a railway to Cuzco from the coast it is almost -impossible for him to get his sugar and cacao to the outside world.<a name="FNanchor_10_10" id="FNanchor_10_10"></a><a href="#Footnote_10_10" class="fnanchor">[10]</a> -How did he manage before even this railway was built? How could the -eastern valley planter live before there were any railways at all in -Peru? In part he has solved the problem as the moonshiner of Kentucky -tried to solve it, and<a name="page_074" id="page_074"></a> from cane juice makes aguardiente (brandy). The -latter is a much more valuable product than sugar, hence (1) it will -bear a higher rate of transportation, or (2) it will at the same rate of -transportation yield a greater net profit. In a remote valley where -sugar could not be exported on account of high freight rates brandy -could still be profitably exported.</p> - -<p>The same may be said for coca and cacao. They are condensed and valuable -products. Both require more labor than sugar but are lighter in bulk and -thus have to bear, in proportion to their value, a smaller share of the -cost of transportation. At the end of three years coca produces over a -ton of leaves per acre per year, and it can be made to produce as much -as two tons to the acre. The leaves are picked four times a year. They -are worth from eight to twelve cents gold a pound at the plantation or -sixteen cents a pound at Cuzco. An orchard of well-cultivated and -irrigated cacao trees will do even better. Once they begin to bear the -trees require relatively little care except in keeping out weeds and -brush and maintaining the water ditches. However, the pods must be -gathered at just the right time, the seeds must be raked and dried with -expert care, and after that comes the arduous labor of the grinding. -This is done by hand on an inclined plane with a heavy round stone whose -corners fit the hand. The chocolate must then be worked into cakes and -dried, or it must be sacked in heavy cowhide and sewed so as to be -practically air tight. When eight or ten years old the trees are mature -and each may then bear a thousand pounds of seed.</p> - -<p><a name="fig_47" id="fig_47"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_074a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_074a_sml.jpg" width="304" height="213" alt="Fig. 47—The Urubamba Valley below Paltaybamba. Harder -rocks intruded into the schists that in general compose the valley walls -here form steep scarps. It has been suggested (Davis) that such a -constricted portion of a valley be called a “shut-in.†The old trail -climbed to the top of the valley and over the back of a huge spur. The -new road is virtually a tunnel blasted along the face of a cliff." /></a> -<br /> - -<table border="0" cellpadding="4" cellspacing="0" summary=""> -<tr valign="top"><td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 47—The Urubamba Valley below Paltaybamba. Harder -rocks intruded into the schists that in general compose the valley walls -here form steep scarps. It has been suggested (Davis) that such a -constricted portion of a valley be called a “shut-in.†The old trail -climbed to the top of the valley and over the back of a huge spur. The -new road is virtually a tunnel blasted along the face of a cliff.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig 48</span>—Coca seed beds near Quillabamba, Urubamba Valley. -The young plants are grown under shade and after attaining a height of a -foot or more are gradually accustomed to sunlight and finally -transplanted to the fields that are to become coca orchards.</p></td></tr> -</table> -</div> - -<p>If labor were cheap and abundant the whole trend of tropical agriculture -in the eastern valleys would be toward intensive cultivation and the -production of expensive exports. But labor is actually scarce. Every -planter must have agents who can send men down from the plateau towns. -And the planter himself must use his labor to the best advantage. -Aguardiente requires less labor than cacao and coca. The cane costs -about as much in labor the first year as the coca bush or the cacao -tree, but after that much less. The manufacture of brandy from the cane -juice requires little labor though much expensive machinery. For -chocolate, a<a name="page_075" id="page_075"></a> storehouse, a grinding stone, and a rake are all that -are required. So the planter must work out his own salvation -individually. He must take account of the return upon investments in -machinery, of the number of hands he can command from among the “faena†-or free Indians, of the cost and number of imported hands from the -valley and plateau towns, and, finally, of the transportation rates -dependent upon the number of mules in the neighborhood, and distance -from the market. If in addition the labor is skilfully employed so as to -have the tasks which the various products require fall at different -periods of the year, then the planter may expect to make money upon his -time and get a return upon his initial investment in the land.<a name="FNanchor_11_11" id="FNanchor_11_11"></a><a href="#Footnote_11_11" class="fnanchor">[11]</a></p> - -<p><a name="fig_49" id="fig_49"></a></p> - -<p><a name="fig_50" id="fig_50"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_074b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_074b_sml.jpg" width="307" height="216" alt="Fig. 49—Fig tree formerly attached to a host but now -left standing on its stilt-like aërial roots owing to the decay of the -host." /></a> -<br /> - -<table border="0" cellpadding="4" cellspacing="0" summary=""> -<tr valign="top"> -<td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 49—Fig tree formerly attached to a host but now -left standing on its stilt-like aërial roots owing to the decay of the -host.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig. 50</span>—A tiny rubber plant is growing under the tripod -made of yuca stems tied with banana leaves. Growing yuca is shown by the -naked stalks to the left and right of this canopy, and banana plants -fill the background. A plantation scene at Echarati.</p></td></tr> -</table> -</div> - -<p>The type of tropical agriculture which we have outlined is profitable -for the few planters who make up the white population of the valleys, -but it has a deplorable effect upon the Indian population. Though the -planters, one and all, complain bitterly of the drunken habits of their -laborers, they themselves put into the hands of the Indians the means of -debauchery. Practically the whole production of the eastern valleys is -consumed in Peru. What the valleys do not take is sent to the plateau, -where it is the chief cause of vicious conduct. Two-thirds of the -prisoners in the city jails are drunkards, and, to be quite plain, they -are virtually supplied with brandy by the planter, who could not -otherwise make enough money. So although the planter wants more and -better labor he is destroying the quality of the little there is, and, -if not actually reducing the quantity of it, he is at least very -certainly reducing the rate of increase.</p> - -<p>The difficulties of the valley planter could be at least partly overcome -in several ways. The railway will reduce transportation costs, -especially when the playas of the valleys are all cleared and the -exports increased. Moreover the eastern valleys<a name="page_076" id="page_076"></a> are capable of -producing things of greater utility than brandy and coca leaves. So far -as profits are increased by cheaper transportation we may expect the -planter to produce more rather than less of brandy and coca, his two -most profitable exports, unless other products can be found that are -still more profitable. The ratio of profits on sugar and brandy will -still be the same unless the government increases the tax on brandy -until it becomes no more profitable than sugar. That is what ought to be -done for the good of the Indian population. It cannot be done safely -without offering in its place the boon of cheaper railway transportation -for the sugar crop. Furthermore, with railway improvements should go the -blessings that agricultural experiments can bestow. A government farm in -a suitable place would establish rice and cotton cultivation. Many of -the playas or lower alluvial lands along the rivers can be irrigated. -Only a small fraction of the water of the Rio Urubamba is now turned out -upon the fields. For a large part of the year the natural rainfall would -suffice to keep rice in good condition. Six tons a year are now grown on -Hacienda Sahuayaco for local use on account of the heavy rate on rice -imported on muleback from Cuzco, whither it comes by sea and by trail -from distant coastal valleys. The lowland people also need rice and it -could be sent to them down river by an easier route than that over which -their supplies now come. It should be exported to the highlands, not -imported therefrom. There are so many varieties adapted to so many kinds -of soil and climate that large amounts should be produced at fair -profits.</p> - -<p>The cotton plant, on the other hand, is more particular about climate -and especially the duration of dry and wet seasons; in spite of this its -requirements are all met in the Santa Ana Valley. The rainfall is -moderate and there is an abundance of dry warm soil. The plant could -make most of its growth in the wet season, and the four months of cooler -dry season with only occasional showers would favor both a bright staple -and a good picking season. More labor would be required for cotton and -rice and for the increased production of cacao than under the present -system. This would not be a real difficulty if the existing labor -supply<a name="page_077" id="page_077"></a> were conserved by the practical abolition, through heavy -taxation, of the brandy that is the chief cause of the laborer’s vicious -habits. This is the first step in securing the best return upon the -capital invested in a railway. Economic progress is here bound up with a -very practical morality. Colonization in the eastern valleys, of which -there have been but a few dismal attempts, will only extend the field of -influence, it will not solve the real problem of bringing the people of -the rich eastern territory of Peru into full and honorable possession of -their natural wealth.</p> - -<p>The value of the eastern valleys was known in Inca times, for their -stone-faced terraces and coca-drying patios may still be seen at -Echarati and on the border of the Chaupimayu Valley at Sahuayaco. -Tradition has it that here were the imperial coca lands, that such of -the forest Indians as were enslaved were obliged to work upon them, and -that the leaves were sent to Cuzco over a paved road now covered with -“montaña†or forest. The Indians still relate that at times a -mysterious, wavering, white light appears on the terraces and hills -where old treasure lies buried. Some of the Indians have gold and silver -objects which they say were dug from the floors of hill caves. There -appears to have been an early occupation of the best lands by the -Spaniards, for the long extensions down them of Quechua population upon -which the conquerors could depend no doubt combined with the special -products of the valley to draw white colonists thither.<a name="FNanchor_12_12" id="FNanchor_12_12"></a><a href="#Footnote_12_12" class="fnanchor">[12]</a><a name="page_078" id="page_078"></a> General -Miller,<a name="FNanchor_13_13" id="FNanchor_13_13"></a><a href="#Footnote_13_13" class="fnanchor">[13]</a> writing in 1836, mentions the villages of Incharate -(Echarati) and Sant’ Ana (Santa Ana) but discourages the idea of -colonization “... since the river ... has lofty mountains on either -side of it, and is not navigable even for boats.â€</p> - -<p>In the “Itinerario de los viajes de Raimondi en el Peruâ€<a name="FNanchor_14_14" id="FNanchor_14_14"></a><a href="#Footnote_14_14" class="fnanchor">[14]</a> there is an -interesting account of the settlement by the Rueda family of the great -estate still held by a Rueda, the wife of Señor Duque. José Rueda, in -1829, was a government deputy representative and took his pay in land, -acquiring valuable territory on which there was nothing more than a -mission. In 1830 Rueda ceded certain lands in “arriendo†(rent) and on -these were founded the haciendas Pucamoco, Sahuayaco, etc.</p> - -<p>Señor Gonzales, the present owner of Hacienda Sahuayaco, recently -obtained his land—a princely estate, ten miles by forty—for 12,000 -soles ($6,000). In a few years he has cleared the best tract, built -several miles of canals, hewed out houses and furniture, planted coca, -cacao, cane, coffee, rice, pepper, and cotton, and would not sell for -$50,000. Moreover, instead of being a superintendent on a neighboring -estate and keeping a shop in Cuzco, where his large family was a source -of great expense, he has become a wealthy landowner. He has educated a -son in the United States. He is importing machinery, such as a rice -thresher and a distilling plant. His son is looking forward to the -purchase of still more playa land down river. He pays a sol a day to -each laborer, securing men from Cotabambas and Abancay, where there are -many Indians, a low standard of wages, little unoccupied land, and a hot -climate, so that the immigrants do not need to become acclimatized.</p> - -<p>The deepest valleys in the Eastern Andes of Peru have a semi-arid -climate which brings in its train a variety of unusual geographic -relations. At first as one descends the valley the shady and sunny -slopes show sharply contrasted vegetation.</p> - -<p><a name="fig_51" id="fig_51"></a></p> - -<p><a name="fig_52" id="fig_52"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_078a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_078a_sml.jpg" width="214" height="328" alt="Fig. 51—Robledo’s mountain-side trail in the Urubamba -Valley below Rosalina." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 51—Robledo’s mountain-side trail in the Urubamba -Valley below Rosalina.</p> - -<p class="caption"><span class="smcap">Fig. 52</span>—An epiphyte partly supported by a dead host at -Rosalina, elevation 2,000 feet. The epiphyte bears a striking -resemblance to a horned beast whose arched back, tightly clasped -fingers, and small eyes give it a peculiarly malignant and life-like -expression.</p> -</div> - -<p><a name="fig_53" id="fig_53"></a></p> -<p><a name="fig_53b" id="fig_53b"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_078b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_078b_sml.jpg" width="209" height="330" alt="Fig. 53A—The smooth grassy slopes at the junction of the -Yanatili (left) and Urubamba (right) rivers near Pabellon." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 53A—The smooth grassy slopes at the junction of the -Yanatili (left) and Urubamba (right) rivers near Pabellon.</p> - -<p class="caption"><span class="smcap">Fig. 53B</span>—Distribution of vegetation in the Urubamba -Valley near Torontoy. The patches of timber in the background occupy the -shady sides of the spurs; the sunny slopes are grass-covered; the valley -floor is filled with thickets and patches of woodland but not true -forest.</p> -</div> - -<p><a name="page_079" id="page_079"></a></p> - -<p>The one is forested, the other grass-covered. Slopes that receive the -noon and afternoon sun the greater part of the year are hottest and -therefore driest. For places in 11° south latitude the sun is well to -the north six months of the year, nearly overhead for about two months, -and to the south four months. Northwesterly aspects are therefore driest -and warmest, hence also grass-covered. In many places the line between -grass and forest is developed so sharply that it seems to be the -artificial edge of a cut-over tract. This is true especially if the -relief is steep and the hill or ridge-crests sharp.<a name="FNanchor_15_15" id="FNanchor_15_15"></a><a href="#Footnote_15_15" class="fnanchor">[15]</a></p> - -<p><a name="fig_54" id="fig_54"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_079_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_079_sml.jpg" width="332" height="57" alt="Fig. 54—Climatic cross-section from the crest of the -Cordillera Vilcapampa down the eastern mountain valleys to the tropical -plains." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 54—Climatic cross-section from the crest of the -Cordillera Vilcapampa down the eastern mountain valleys to the tropical -plains.</p> -</div> - -<p>At Santa Ana this feature is developed in an amazingly clear manner, and -it is also combined with the dry timber line and with productivity in a -way I have never seen equaled elsewhere. The diagram will explain the -relation. It will be seen that the front range of the mountains is high -enough to shut off a great deal of rainfall. The lower hills and ridges -just within the front range are relatively dry. The deep valleys are -much drier. Each broad expansion of a deep valley is therefore a dry -pocket. Into it the sun pours even when<a name="page_080" id="page_080"></a> all the surrounding hills and -mountains are wrapped in cloud. The greater number of hours of sunshine -hastens the rate of evaporation and still further increases the dryness. -Under the spur of much sunlight and of ample irrigation water from the -wetter hill slopes, the dry valley pockets produce huge crops of fruit -and cane.</p> - -<p>The influence of the local climate upon tree growth is striking. Every -few days, even in the relatively dry winter season, clouds gather about -the hills and there are local showers. The lower limit of the zone of -clouds is sharply marked and at both Santa Ana and Echarati it is -strikingly constant in elevation—about five thousand feet above sea -level. From the upper mountains the forest descends, with only small -patches of glade and prairie. At the lower edge of the zone of cloud it -stops abruptly on the warmer and drier slopes that face the afternoon -sun and continues on the moister slopes that face the forenoon sun or -that slope away from the sun.</p> - -<p>But this is not the only response the vegetation makes. The forest -changes in character as well as in distribution. The forest in the wet -zone is dense and the undergrowth luxuriant. In the selective slope -forest below the zone of cloud the undergrowth is commonly thin or -wanting and the trees grow in rather even-aged stands and by species. -Finally, on the valley floor and the tributary fans, there is a distinct -growth of scrub with bands of trees along the water courses. Local -tracts of coarse soil, or less rain on account of a deep “hole†in a -valley surrounded by steeper and higher mountains, or a change in the -valley trend that brings it into less free communication with the -prevailing winds, may still further increase the dryness and bring in a -true xerophytic or drought-resisting vegetation. Cacti are common all -through the Santa Ana Valley and below Sahuayaco there is a patch of -tree cacti and similar forms several square miles in extent. Still -farther down and about half-way between Sahuayaco and Pabellon are -immense tracts of grass-covered mountain slopes (<a href="#fig_53">Fig. 53</a>). These extend -beyond Rosalina, the last of them terminating near Abra Tocate (Fig. -15). The sudden interruption is due to a<a name="page_081" id="page_081"></a> turn in the valley giving -freer access to the up-valley winds that sweep through the pass at Pongo -de Mainique.</p> - -<p><a name="fig_55" id="fig_55"></a></p> - -<div class="figright" style="width: 125px;"> -<a href="images/ill_page_081_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_081_sml.jpg" width="125" height="139" alt="Fig. 55—Map to show the relation of the grasslands of -the dry lower portion of the Urubamba Valley (unshaded) to the forested -lands at higher elevations (shaded). See Fig. 54 for climatic -conditions. Patches and slender tongues of woodland occur below the main -timber line and patches of grassland above it." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 55—Map to show the relation of the grasslands of -the dry lower portion of the Urubamba Valley (unshaded) to the forested -lands at higher elevations (shaded). See <a href="#fig_54">Fig. 54</a> for climatic -conditions. Patches and slender tongues of woodland occur below the main -timber line and patches of grassland above it.</p> -</div> - -<p>Northward from Abra Tocate (<a href="#fig_55">Fig. 55</a>) the forest is practically -continuous. The break between the two vegetal regions is emphasized by a -corral for cattle and mules, the last outpost of the plateau herdsmen. -Not three miles away, on the opposite forested slope of the valley, is -the first of the Indian clearings where several families of Machigangas -spend the wet season when the lower river is in flood (<a href="#fig_21">Fig. 21</a>). The -grass lands will not yield corn and coca because the soil is too thin, -infertile, and dry. The Indian farms are therefore all in the forest and -begin almost at its very edge. Here finally terminates a long peninsula -of grass-covered country. Below this point the heat and humidity rapidly -increase; the rains are heavier and more frequent; the country becomes -almost uninhabitable for stock; transportation rates double. Here is the -undisputed realm of the forest with new kinds of trees and products and -a distinctive type of forest-dwelling Indian.</p> - -<p>At the next low pass is the skull of an Italian who had murdered his -companions and stolen a season’s picking of rubber, attempting to escape -by canoe to the lower Urubamba from the Pongo de Mainique. The -Machigangas overtook him in their swiftest dugouts, spent a night with -him, and the next morning shot him in the back and returned with their -rightful property—<a name="page_082" id="page_082"></a>a harvest of rubber. For more than a decade -foreigners have been coming down from the plateau to exploit them. They -are an independent and free tribe and have simple yet correct ideas of -right and wrong. Their chief, a man of great strength of character and -one of the most likeable men I have known, told me that he placed the -skull in the pass to warn away the whites who came to rob honest -Indians.</p> - -<p>The Santa Ana Valley between the Canyon of Torontoy and the heavy forest -belt below Rosalina is typical of many of the eastern valleys of Peru, -both in its physical setting and in its economic and labor systems. -Westward are the outliers of the Vilcapampa range; on the east are the -smaller ranges that front the tropical lowlands. Steep valleys descend -from the higher country to join the main valley and at the mouth of -every tributary is an alluvial fan. If the alluvium is coarse and -steeply inclined there is only pasture on it or a growth of scrub. If -fine and broad it is cleared and tilled. The sugar plantations begin at -Huadquiña and end at Rosalina. Those of Santa Ana and Echarati are the -most productive. It takes eighteen months for the cane to mature in the -cooler weather at Huadquiña (8,000 feet). Less than a year is required -at Santa Ana (3,400 feet). Patches of alluvium or playas, as they are -locally called, continue as far as Santo Anato, but they are cultivated -only as far as Rosalina. The last large plantation is Pabellon; the -largest of all is Echarati. All are irrigated. In the wet months, -December to March inclusive, there is little or no irrigation. In the -four months of the dry season, June to September inclusive, there is -frequent irrigation. Since the cane matures in about ten months the -harvest seasons fall irregularly with respect to the seasons of rain. -Therefore the land is cleared and planted at irregular intervals and -labor distributed somewhat through the year. There is however a -concentration of labor toward the end of the dry season when most of the -cane is cut for grinding.</p> - -<p>The combined freight rate and government tax on coca, sugar, and brandy -take a large part of all that the planter can get for his crop. It is -120 miles (190 km.) from Santa Ana to Cuzco and<a name="page_083" id="page_083"></a> it takes five days to -make the journey. The freight rate on coca and sugar for mule carriage, -the only kind to be had, is two cents per pound. The national tax is one -cent per pound (0.45 kg.). The coca sells for twenty cents a pound. The -cost of production is unknown, but the paid labor takes probably -one-half this amount. The planter’s time, capital, and profit must come -out of the rest. On brandy there is a national tax of seven cents per -liter (0.26 gallon) and a municipal tax of two and a half cents. It -costs five cents a liter for transport to Cuzco. The total in taxes and -transport is fourteen and a half cents a liter. It sells for twenty -cents a liter. Since brandy (aguardiente), cacao (for chocolate), and -coca leaves (for cocaine) are the only precious substances which the -valleys produce it takes but a moment’s inspection to see how onerous -these taxes would be to the planter if labor did not, as usual, pay the -penalty.</p> - -<p>Much of the labor on the plantations is free of cost to the owner and is -done by the so-called <i>faena</i> or free Indians. These are Quechuas who -have built their cabins on the hill lands of the planters, or on the -floors of the smaller valleys. The disposition of their fields in -relation to the valley plantations is full of geographic interest. Each -plantation runs at right angles to the course of the valley. Hacienda -Sahuayaco is ten miles (16 km.) in extent down valley and forty miles -(64 km.) from end to end across the valley, and it is one of the smaller -plantations! It follows that about ten square miles lie on the valley -floor and half of this can ultimately be planted. The remaining three -hundred and ninety square miles include some mountain country with -possible stores of mineral wealth, and a great deal of “fells†-country—grassy slopes, graded though steep, excellent for pasture, with -here and there patches of arable land. But the hill country can be -cultivated only by the small farmer who supplements his supply of food -from cultivated plants like potatoes, corn, and vegetables, by keeping -cattle, mules, pigs, and poultry, and by raising coca and fruit.</p> - -<p>The Indian does not own any of the land he tills. He has the right -merely to live on it and to cultivate it. In return he must<a name="page_084" id="page_084"></a> work a -certain number of days each year on the owner’s plantation. In many -cases a small money payment is also made to the planter. The planter -prefers labor to money, for hands are scarce throughout the whole -eastern valley region. No Indian need work on the planter’s land without -receiving pay directly therefor. Each also gets a small weekly allotment -of aguardiente while in the planter’s employ.</p> - -<p>The scene every Saturday night outside the office of the <i>contador</i> -(treasurer) of a plantation is a novel one. Several hundred Indians -gather in the dark patio in front of the office. Within the circle of -the feeble candlelight that reaches only the margin of the crowd one may -see a pack of heavy, perspiring faces. Many are pock-marked from -smallpox; here and there an eye is missing; only a few are jovial. A -name is shouted through the open door and an Indian responds. He pulls -off his cap and stands stupid and blinking, while the contador asks:</p> - -<p>“Faena†(free)?</p> - -<p>“Si, Señor,†he answers.</p> - -<p>“Un sol†(one “sol†or fifty cents gold). The assistant hands over the -money and the man gives way to the next one on the list. If he is a -laborer in regular and constant employ he receives five soles (two fifty -gold) per week. There are interruptions now and then. A ragged, -half-drunken man has been leaning against the door post, suspiciously -impatient to receive his money. Finally his name is called.</p> - -<p>“Faena?†asks the contador.</p> - -<p>“No, Señor, cinco (five) soles.â€</p> - -<p>At that the field <i>superintendente</i> glances at his time card and speaks -up in protest.</p> - -<p>“You were the man that failed to show up on Friday and Saturday. You -were drunk. You should receive nothing.â€</p> - -<p>“No, mi patrón,†the man contends, “I had to visit a sick cousin in the -next valley. Oh, he was very sick, Señor,†and he coughs harshly as if -he too were on the verge of prostration. The sick cousin, a faena -Indian, has been at work in another cane field on the same plantation -for two days and now calls out that he is<a name="page_085" id="page_085"></a> present and has never had a -sick day in his life. Those outside laugh uproariously. The contador -throws down two soles and the drunkard is pushed back into the sweating -crowd, jostled right and left, and jeered by all his neighbors as he -slinks away grumbling.</p> - -<p>Another Indian seems strangely shy. He scarcely raises his voice above a -whisper. He too is a faena Indian. The contador finds fault.</p> - -<p>“Why didn’t you come last month when I sent for you?â€</p> - -<p>The Indian fumbles his cap, shuffles his feet, and changes his coca cud -from one bulging cheek to the other before he can answer. Then huskily:</p> - -<p>“I started, Señor, but my woman overtook me an hour afterward and said -that one of the ewes had dropped a lamb and needed care.â€</p> - -<p>“But your woman could have tended it!â€</p> - -<p>“No, Señor, she is sick.â€</p> - -<p>“How, then, could she have overtaken you?†he is asked.</p> - -<p>“She ran only a little way and then shouted to me.â€</p> - -<p>“And what about the rest of the month?†persists the contador.</p> - -<p>“The other lambs came, Señor, and I should have lost them all if I had -left.â€</p> - -<p>The contador seems at the end of his complaint. The Indian promises to -work overtime. His difficulties seem at an end, but the superintendent -looks at his old record.</p> - -<p>“He always makes the same excuse. Last year he was three weeks late.â€</p> - -<p>So the poor shepherd is fined a sol and admonished that his lands will -be given to some one else if he does not respond more promptly to his -patron’s call for work. He leaves behind him a promise and the rank -mixed smell of coca and much unwashed woolen clothing.</p> - -<p>It is not alone at the work that they grumble. There is malaria in the -lower valleys. Some of them return to their lofty mountain homes -prostrated with the unaccustomed heat and alternately shaking with -chills and burning with fever. Without aid<a name="page_086" id="page_086"></a> they may die or become so -weakened that tuberculosis carries them off. Only their rugged strength -enables the greater number to return in good health.</p> - -<p>A plantation may be as large as a principality and draw its laborers -from places fifty miles away. Some of the more distant Indians need not -come to work in the canefields. Part of their flock is taken in place of -work. Or they raise horses and mules and bring in a certain number each -year to turn over to the patron. Hacienda Huadquiña (<a href="#fig_46">Fig. 46</a>) takes in -all the land from the snow-covered summits of the Cordillera Vilcapampa -to the canefields of the Urubamba. Within the broad domain are half the -climates and occupations characteristic of Peru. It is difficult to see -how a thousand Indians can be held to even a mixed allegiance. It seems -impossible that word can be got to them. However the native “telegraph†-is even more perfect than that among the forest Indians. From one to the -other runs the news that they are needed in the canefields. On the trail -to and from a mountain village, in their ramblings from one high pasture -to another, within the dark walls of their stone and mud huts when they -gather for a feast or to exchange drinks of brandy and <i>chicha</i>—the -word is passed that has come up from the valleys.</p> - -<p>For every hundred faena Indians there are five or six regular laborers -on the plantations, so with the short term passed by the faena Indians -their number is generally half that of the total laborers at work at any -one time. They live in huts provided for them by the planter, and in the -houses of their friends among the regular laborers. Here there are -almost nightly carousals. The regular laborer comes from the city or the -valley town. The faena laborer is a small hill farmer or shepherd. They -have much to exchange in the way of clothing, food, and news. I have -frequently had their conversations interpreted for me. They ask about -the flocks and the children, who passed along the trails, what accidents -befell the people.</p> - -<p>“Last year,†droned one to another over their chicha, “last year we lost -three lambs in a hailstorm up in the high fields near the snow. It was -very cold. My foot cracked open and, though<a name="page_087" id="page_087"></a> I have bound it with wet -coca leaves every night, it will not cure,†and he displays his heel, -the skin of which is like horn for hardness and covered with a crust of -dirt whose layers are a record of the weather and of the pools he has -waded for years.</p> - -<p>Their wanderings are the main basis of conversation. They know the -mountains better than the condors do. We hired a small boy of twelve at -Puquiura. He was to build our fires, carry water, and help drive the -mules. He crossed the Cordillera Vilcapampa on foot with us. He -scrambled down into the Apurimac canyon and up the ten thousand feet of -ascent on the other side, twisted the tails of the mules, and shouted -more vigorously then the arrieros. He was engaged to go with us to -Pasaje, where his father would return with him in a month. But he -climbed to Huascatay with us and said he wanted to see Abancay. When an -Indian whom we pressed into service dropped the instruments on the trail -and fled into the brush the boy packed them like a man. The soldier -carried a tripod on his back. The boy, not to be outdone, insisted on -carrying the plane table, and to his delight we called him a soldier -too. He went with us to Huancarama. When I paid him he smiled at the -large silver soles that I put into his hand; and when I doubled the -amount for his willingness to work his joy was unbounded. Forthwith he -set out, this time on muleback, on the return journey. The last I saw of -him he was holding his precious soles in a handkerchief and kicking his -beast with his bare heels, as light-hearted as a cavalier. Often I find -myself wondering whether he returned safely with his money. I should -very much like to see him again, for with him I associate cheerfulness -in difficult places and many a pleasant camp-fire.<a name="page_088" id="page_088"></a></p> - -<h3><a name="CHAPTER_VII" id="CHAPTER_VII"></a>CHAPTER VII<br /><br /> -THE GEOGRAPHIC BASIS OF REVOLUTIONS AND OF HUMAN CHARACTER IN THE PERUVIAN ANDES</h3> - -<p>H<small>UMAN</small> character as a spontaneous development has always been a great -factor in shaping historical events, but it is a striking fact that in -the world of our day its influence is exerted chiefly in the lowest and -highest types of humanity. The savage with his fetishes, his taboos, and -his inherent childlikeness and suspicion needs only whim or a slight -religious pretext to change his conduct. Likewise the really educated -and the thoughtful act from motives often wholly unrelated to economic -conditions or results. But the masses are deeply influenced by whatever -affects their material welfare. A purely idealistic impulse may -influence a people, but in time its effects are always displayed against -an economic background.</p> - -<p>There is a way whereby we may test this theory. In most places in the -world we have history in the making, and through field studies we can -get an intimate view of it. It is peculiarly the province of geography -to study the present distribution and character of men in relation to -their surroundings and these are the facts of mankind that must forever -be the chief data of economic history. It is not vain repetition to say -that this means, first of all, the study of the character of men in the -fullest sense. It means, in the second place, that a large part of the -character must be really understood. Whenever this is done there is -found a geographic basis of human character that is capable of the -clearest demonstration. It is in the geographic environment that the -material motives of humanity have struck their deepest roots.</p> - -<p>These conclusions might be illustrated from a hundred places in the -field of study covered in this book. Almost every chapter of Part I -contains facts of this character. I wish, however, to discuss<a name="page_089" id="page_089"></a> the -subject specifically and for that purpose now turn to the conditions of -life in the remoter mountain valleys and to one or two aspects of the -revolutions that occur now and then in Peru. The last one terminated -only a few months before our arrival and it was a comparatively easy -matter to study both causes and effects.</p> - -<p>A caution is necessary however. It is a pity that we use the term -“revolution†to designate these little disturbances. They affect -sometimes a few, again a few hundred men. Rarely do they involve the -whole country. A good many of them are on a scale much smaller than our -big strikes. Most of them involve a loss of life smaller than that which -accompanies a city riot. They are in a sense strikes against the -government, marked by local disorders and a little violence.</p> - -<p>Early in 1911 the Prefect of the Department of Abancay had crowned his -long career by suppressing a revolution. He had been Subprefect at -Andahuaylas, and when the rebels got control of the city of Abancay and -destroyed some of the bridges on the principal trails, he promptly -organized a military expedition, constructed rafts, floated his small -force of men across the streams, and besieged the city. The rebel force -was driven at last to take shelter in the city jail opposite the -Prefectura. There, after the loss of half their number, they finally -surrendered. Seventy-five of them were sent to the government -penitentiary at Arequipa. Among the killed were sons from nearly half -the best families of Abancay. All of the rebels were young men.</p> - -<p>It would be difficult to give an adequate idea of the hatred felt by the -townspeople toward the government. Every precaution was taken to prevent -a renewal of the outbreak. Our coming was telegraphed ahead by -government agents who looked with suspicion upon a party of men, well -armed and provisioned, coming up from the Pasaje crossing of the -Apurimac, three days’ journey north. The deep canyon affords shelter not -only to game, but also to fugitives, rebels, and bandits. The government -generally abandons pursuit on the upper edge of the canyon, for only a -prolonged guerilla warfare could completely subdue an armed force<a name="page_090" id="page_090"></a> -scattered along its rugged walls and narrow floor. The owner of the -hacienda at Pasaje is required to keep a record of all passengers rafted -across the Apurimac, but he explains significantly that some who pass -are too hurried to write their names in his book. Once he reaches the -eastern wall of the canyon a fugitive may command a view of the entire -western wall and note the approach of pursuers. Thence eastward he has -the whole Cordillera Vilcapampa in which to hide. Pursuit is out of the -question.</p> - -<p>When we arrived, the venerable Prefect, a model of old-fashioned -courtesy, greeted us with the utmost cordiality. He told us of our -movements since leaving Pasaje, and laughingly explained that since we -had sent him no friendly message and had come from a rebel retreat, he -had taken it for granted that we intended to storm the town. I assured -him that we were ready to join his troops, if necessary, whereupon, with -a delightful frankness, he explained his method of keeping the situation -in hand. Several troops of cavalry and two battalions of infantry were -quartered at the government barracks. Every evening the old gentleman, a -Colonel in the Peruvian army, mounted a powerful gray horse and rode, -quite unattended, through the principal streets of the town. Several -times I walked on foot behind him, again I preceded him, stopping in -shops on the way to make trivial purchases, to find out what the people -had to say about him and the government as he rode by. One old gentleman -interested me particularly. He had only the day before called at the -Prefectura to pay his respects. Although his manner was correct there -was lacking to a noticeable degree the profusion of sentiment that is -apt to be exhibited on such an occasion. He now sat on a bench in a -shop. Both his own son and the shopkeeper’s son had been slain in the -revolution. It was natural that they should be bitter. But the precise -nature of their complaint was what interested me most. One said that he -did not object to having his son lose his life for his country. But that -his country’s officials should hire Indians to shoot his son seemed to -him sheer murder. Later, at Lambrama, I talked with a rebel fugitive, -and that was also his complaint. The young men drafted into the army are -Indians, or<a name="page_091" id="page_091"></a> mixed, never whites. White men, and men with a small -amount of Indian blood, officer the army. When a revolutionary party -organizes it is of course made up wholly of men of white and mixed -blood, never Indians. The Indians have no more grievance against one -white party than another. Both exploit him to the limit of law and -beyond the limit of decency. He fights if he must, but never by choice.</p> - -<p><a name="fig_56" id="fig_56"></a></p> - -<p><a name="fig_57" id="fig_57"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_090a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_090a_sml.jpg" width="314" height="212" alt="Fig. 56—The type of forest in the moister tracts of the -valley floor at Sahuayaco. In the center of the photograph is a tree -known as the “sandy matico†used in making canoes for river navigation." /></a> -<br /> - -<table border="0" cellpadding="5" cellspacing="0" summary=""> -<tr valign="top"> -<td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 56—The type of forest in the moister tracts of the -valley floor at Sahuayaco. In the center of the photograph is a tree -known as the “sandy matico†used in making canoes for river navigation.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig. 57</span>—Arboreal cacti in the mixed forest of the dry -valley floor below Sahuayaco.</p></td></tr> -</table> -</div> - -<p><a name="fig_58" id="fig_58"></a></p> - -<p><a name="fig_59" id="fig_59"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_090b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_090b_sml.jpg" width="206" height="329" alt="Fig. 58—Crossing the Apurimac at Pasaje. These are -mountain horses, small and wiry, with a protective coat of long hair. -They are accustomed to graze in the open without shelter during the -entire winter." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 58—Crossing the Apurimac at Pasaje. These are -mountain horses, small and wiry, with a protective coat of long hair. -They are accustomed to graze in the open without shelter during the -entire winter.</p> - -<p class="caption"><span class="smcap">Fig. 59</span>—Crossing the Apurimac at Pasaje. The mules are -blindfolded and pushed off the steep bank into the water and rafted -across.</p> -</div> - -<p>Thus Indian troops killed the white rebels of Abancay.</p> - -<p>“Tell me, Señor,†said the fugitive, “if you think that just. Tell me -how many Indians you think a white man worth. Would a hundred dead -Indians matter? But how replace a white man where there are so few? The -government <i>assassinated</i> my compatriots!â€</p> - -<p>“But,†I replied, “why did you fight the government? All of you were -prosperous. Your fathers may have had a grievance against the -government, but of what had you young men to complain?â€</p> - -<p>His reply was far from convincing. He was at first serious, but his long -abstract statements about taxes and government wastefulness trailed off -into vagueness, and he ended in a laughing mood, talking about -adventure, the restless spirit of young men, and the rich booty of -confiscated lands and property had the rebels won. He admitted that it -was a reckless game, but when I called him a mere soldier of fortune he -grew serious once more and reverted to the iniquitous taxation system of -Peru. Further inquiry made it quite clear that the ill-fated revolution -of Abancay was largely the work of idle young men looking for adventure. -It seemed a pity that their splendid physical energy could not have been -turned into useful channels. The land sorely needs engineers, -progressive ranchmen and farmers, upright officials, and a spirit of -respect for law and order. Old men talked of the unstable character of -the young men of the time, but almost all of them had themselves been -active participants in more than one revolution of earlier years.</p> - -<p>Every night at dinner the Prefect sent off by government telegraph a -long message to the President of the Republic on the<a name="page_092" id="page_092"></a> state of the -Department, and received similar messages from the central government -about neighboring departments. These he read to us, and, curiously -enough, to the entire party, made up of army officers and townsmen. I -was surprised to find later that the company included one government -official whose son had been among the imprisoned rebels at Arequipa. We -met the young man a week later at a mountain village, a day after a -general amnesty had been declared. His escape had been made from the -prison a month before. He forcibly substituted the mess-boy’s clothing -for his own, and thus passed out unnoticed. After a few days’ hiding in -the city, he set out alone across the desert of Vitor, thence across the -lofty volcanic country of the Maritime Andes, through some of the most -deserted, inhospitable land in Peru, and at the end of three weeks had -reached Lambrama, near Abancay, the picture of health!</p> - -<p>Later I came to have a better notion of the economic basis of the -revolution, for obviously the planters and the reckless young men must -have had a mutual understanding. Somewhere the rebels had obtained the -sinews of war. The planters did not take an open part in the revolution, -but they financed it. When the rebels were crushed, the planters, at -least outwardly, welcomed the government forces. Inwardly they cursed -them for thwarting their scheme. The reasons have an interesting -geographic basis. Abancay is the center of a sugar region. Great -irrigated estates are spread out along the valley floor and the enormous -alluvial fans built into the main valley at the mouths of the tributary -streams. There is a heavy tax on sugar and on aguardiente (brandy) -manufactured from cane juice. The <i>hacendados</i> had dreamed of lighter -taxes. The rebels offered the means of securing relief. But taxes were -not the real reason for the unrest, for many other sugar producers pay -the tax without serious complaint. Abancay is cut off from the rest of -Peru by great mountains. Toward the west, <i>via</i> Antabamba, Cotahuasi, -and Chuquibamba, two hundred miles of trail separate its plantations -from the Pacific. Twelve days’ hard riding is required to reach Lima -over the old colonial trade route. It is three days to Cuzco at the<a name="page_093" id="page_093"></a> end -of the three-hundred-mile railway from the port of Mollendo. The trails -to the Atlantic rivers are impossible for trading purposes. Deep sunk in -a subtropical valley, the irrigable alluvial land of Abancay tempts the -production of sugar.</p> - -<p>But nature offers no easy route out of the valley. For centuries the -product has been exported at almost prohibitive cost, as in the eastern -valley of Santa Ana. The coastal valleys enjoy easy access to the sea. -Each has its own port at the valley mouth, where ocean steamers call for -cargo. Many have short railway lines from port to valley head. The -eastern valleys and Abancay have been clamoring for railways, better -trails, and wagon roads. From the public fund they get what is left. The -realization of their hopes has been delayed too long. It would be both -economic and military strategy to give them the desired railway. -Revolutions in Peru always start in one of two ways: either by a <i>coup</i> -at Lima or an unchecked uprising in an interior province. Bolivia has -shown the way out of this difficulty. Two of her four large centers—La -Paz and Oruro—are connected by rail, and the line to Cochabamba lacks -only a few kilometres of construction.<a name="FNanchor_16_16" id="FNanchor_16_16"></a><a href="#Footnote_16_16" class="fnanchor">[16]</a> To Sucre a line has been long -projected. Formerly a revolution at one of the four towns was -exceedingly difficult to stamp out. Diaz had the same double motive in -encouraging railway building in the remote desert provinces of Northern -Mexico, where nine out of ten Mexican revolutions gather headway. -Argentina has enjoyed a high degree of political unity since her railway -system was extended to Córdoba and Tucumán. The last uprising, that of -1906, took place on her remotest northeastern frontier.</p> - -<p>We had ample opportunity to see the hatred of the rebels. At nightfall -of September 25th we rode into the courtyard of Hacienda Auquibamba. We -had traveled under the worst possible<a name="page_094" id="page_094"></a> circumstances. Our mules had been -enfeebled by hot valley work at Santa Ana and the lower Urubamba and the -cold mountain climate of the Cordillera Vilcapampa. The climb out of the -Apurimac canyon, even without packs, left them completely exhausted. We -were obliged to abandon one and actually to pull another along. It had -been a hard day in spite of a prolonged noon rest. Everywhere our -letters of introduction had won an outpouring of hospitality among a -people to whom hospitality is one of the strongest of the unwritten laws -of society. Our soldier escort rode ahead of the pack train.</p> - -<p>As the clatter of his mules’ hoofs echoed through the dark buildings the -manager rushed out, struck a light and demanded “Who’s there?†To the -soldier’s cheerful “Buena noche, Señor,†he sneeringly replied “Halto! -Guardia de la República, aqui hay nada para un soldado del gobierno.†-Whereupon the soldier turned back to me and said we should not be able -to stop here, and coming nearer me he whispered “He is a revolutionary.†-I dismounted and approached the haughty manager, who was in a really -terrible mood. Almost before I could begin to ask him for accommodations -he rattled off that there was no pasture for our beasts, no food for us, -and that we had better go on to the next hacienda. “Absolutamente nada!†-he repeated over and over again, and at first I thought him drunk. Since -it was then quite dark, with no moon, but instead heavy black clouds -over the southern half of the sky and a brisk valley wind threatening -rain, I mildly protested that we needed nothing more than shelter. Our -food boxes would supply our wants, and our mules, even without fodder, -could reach Abancay the next day. Still he stormed at the government and -would have none of us. I reminded him that his fields were filled with -sugar cane and that it was the staple forage for beasts during the part -of the year when pasture was scarce. The cane was too valuable, he said. -It was impossible to supply us. I was on the point of pitching camp -beside the trail, for it was impossible to reach the next hacienda with -an exhausted outfit.</p> - -<p>Just then an older man stepped into the circle of light and amiably<a name="page_095" id="page_095"></a> -inquired the purpose of our journey. When it was explained, he turned to -the other and said it was unthinkable that men should be treated so -inhospitably in a strange land. Though he himself was a guest he urged -that the host should remember the laws of hospitality, whereupon the -latter at last grudgingly asked us to join him at his table and to turn -our beasts over to his servants. It was an hour or more before he would -exhibit any interest in us. When he had learned of our object in -visiting Abancay he became somewhat more friendly, though his hostility -still manifested itself. Nowhere else in South America have I seen -exhibited such boorish conduct. Nevertheless the next morning I noticed -that our mules had been well fed. He said good-by to us as if he were -glad to be rid of any one in any way connected with the hostile -government. Likewise the manager at Hacienda Pasaje held out almost -until the last before he would consent to aid us with fresh beasts. -Finally, after a day of courting I gave him a camp chair. He was so -pleased that he not only gave us beasts, but also a letter of -introduction to one of his caretakers on a farm at the top of the -cuesta. Here on a cold, stormy night we found food and fuel and the -shelter of a friendly roof.</p> - -<p>A by-product of the revolution, as of all revolutions in thinly settled -frontier regions, was the organization of small bands of outlaws who -infested the lonely trails, stole beasts, and left their owners robbed -and helpless far from settlements. We were cautioned to beware of them, -both by Señor Gonzales, the Prefect at Abancay, and by the Subprefect of -Antabamba. Since some of the bandits had been jailed, I could not doubt -the accuracy of the reports, but I did doubt stories of murder and of -raids by large companies of mountain bandits. As a matter of fact we -were robbed by the Governor of Antabamba, but in a way that did not -enable us to find redress in either law or lead. The story is worth -telling because it illustrates two important facts: first, the vile -so-called government that exists in some places in the really remote -sections of South America, and second, the character of the mountain -Indians.</p> - -<p>The urgent letter from the Prefect of Abancay to the Subprefect<a name="page_096" id="page_096"></a> of -Antabamba quickly brought the latter from his distant home. When we -arrived we found him drinking with the Governor. The Subprefect was most -courteous. The Governor was good-natured, but his face exhibited a rare -combination of cruelty and vice. We were offered quarters in the -municipal building for the day or two that we were obliged to stop in -the town. The delay enabled us to study the valley to which particular -interest attaches because of its situation in the mountain zone between -the lofty pastures of the Alpine country and the irrigated fields of the -valley farmers.</p> - -<p>Antabamba itself lies on a smooth, high-level shoulder of the youthful -Antabamba Valley. The valley floor is narrow and rocky, and affords -little cultivable land. On the valley sides are steep descents and -narrow benches, chiefly structural in origin, over which there is -scattered a growth of scrub, sufficient to screen the deer and the bear, -and, more rarely, vagrant bands of vicuña that stray down from their -accustomed haunts in the lofty Cordillera. Three thousand feet above the -valley floor a broad shoulder begins (<a href="#fig_60">Fig. 60</a>) and slopes gently up to -the bases of the true mountains that surmount the broad rolling summit -platform. Here are the great pasture lands of the Andes and their -semi-nomadic shepherds. The highest habitation in the world is located -here at 17,100 feet (5,210 m.), near a secondary pass only a few miles -from the main axis of the western chain, and but 300 feet (91 m.) below -it.</p> - -<p>The people of Antabamba are both shepherds and farmers. The elevation is -12,000 feet (3,658 m.), too high and exposed for anything more than -potatoes. Here is an Indian population pure-blooded, and in other -respects, too, but little altered from its original condition. There is -almost no communication with the outside world. A deep canyon fronts the -town and a lofty mountain range forms the background.</p> - -<p>At nightfall, one after another, the Indians came in from the field and -doffed their caps as they passed our door. Finally came the “Teniente -Gobernador,†or Lieutenant Governor. He had only a slight strain of -white blood. His bearing was that of a<a name="page_097" id="page_097"></a> sneak, and he confirmed this -impression by his frank disdain for his full-blooded townsmen. “How -ragged and ugly they are! You people must find them very stupid,†etc. -When he found that we had little interest in his remarks, he asked us if -we had ever seen Lima. We replied that we had, whereupon he said, “Do -you see the gilded cross above the church yonder? I brought that on -muleback all the way from Lima! Think of it! These ignorant people have -never seen Lima!†His whole manner as he drew himself up and hit his -breast was intended to make us think that he was vastly superior to his -neighbors. The sequel shows that our first estimate of him was correct.</p> - -<p>We made our arrangements with the Governor and departed. To inspire -confidence, and at the Governor’s urgent request, we had paid in advance -for our four Indians and our fresh beasts—and at double the usual -rates, for it was still winter in the Cordillera. They were to stay with -us until we reached Cotahuasi, in the next Department beyond the -continental divide, where a fresh outfit could be secured. The -Lieutenant Governor accompanied us to keep the party together. They -appeared to need it. Like our Indian peons at Lambrama the week before, -these had been taken from the village jail and represented the scum of -the town. As usual they behaved well the first day. On the second night -we reached the Alpine country where the vegetation is very scanty and -camped at the only spot that offered fuel and water. The elevation was -16,000, and here we had the lowest temperature of the whole journey, +6° -F. (-14.4° C.). Ice covered the brook near camp as soon as the sun went -down and all night long the wind blew down from the lofty Cordillera -above us, bringing flurries of snow and tormenting our unprotected -beasts. It seemed to me doubtful if our Indians would remain. I -discussed with the other members of the party the desirability of -chaining the peons to the tent pole, but this appeared so extreme a -measure that we abandoned the idea after warning the Teniente that he -must not let them escape.</p> - -<p>At daybreak I was alarmed at the unusual stillness about camp. A glance -showed that half our hobbled beasts had<a name="page_098" id="page_098"></a> drifted back toward Antabamba -and no doubt were now miles away. The four Indian peons had left also, -and their tracks, half buried by the last snowfall, showed that they had -left hours before and that it was useless to try to overtake them. -Furthermore we were making a topographic map across the Cordillera, and, -in view of the likelihood of snow blockading the 17,600-foot (5,360 m.) -pass which we had to cross, the work ought not to be delayed. With all -these disturbing conditions to meet, and suffering acutely from mountain -sickness, I could scarcely be expected to deal gently with our official. -I drew out the sleeping Teniente and set him on his feet. To my inquiry -as to the whereabouts of the Indians that he had promised to guard, he -blinked uncertainly, and after a stupid “Quien sabe?†peered under the -cover of a sheepskin near by as if the peons had been transformed into -insects and had taken refuge under a blade of grass. I ordered him to -get breakfast and after that to take upon his back the instruments that -two men had carried up to that time, and accompany the topographer. Thus -loaded, the Lieutenant Governor of Antabamba set out on foot a little -ahead of the party. Hendriksen, the topographer, directed him to a -17,000-foot peak near camp, one of the highest stations occupied in the -traverse. When the topographer reached the summit the instruments were -there but the Teniente had fled. Hendriksen rapidly followed the tracks -down over the steep snow-covered wall of a deeply recessed cirque, but -after a half-hour’s search could not get sight of the runaway, whereupon -he returned to his station and took his observations, reaching camp in -the early afternoon.</p> - -<p>In the meantime I had intercepted two Indians who had come from -Cotahuasi driving a llama train loaded with corn. They held a long -conversation at the top of the pass above camp and at first edged -suspiciously away. But the rough ground turned them back into the trail -and at last they came timidly along. They pretended not to understand -Spanish and protested vigorously that they had to keep on with their -llamas. I thought from the belligerent attitude of the older, which grew -rapidly more threatening as he saw that I was alone, that I was in for -trouble, but when<a name="page_099" id="page_099"></a> I drew my revolver he quickly obeyed the order to sit -down to breakfast, which consisted of soup, meat, and army biscuits. I -also gave them coca and cigarettes, the two most desirable gifts one can -make to a plateau Indian, and thereupon I thought I had gained their -friendship, for they at last talked with me in broken Spanish. The older -one now explained that he must at all hazards reach Matará by nightfall, -but he would be glad to leave his son to help us. I agreed, and he set -out forthwith. The <i>arriero</i> (muleteer) had now returned with the lost -mules and with the assistance of the Indian we soon struck camp and -loaded our mules. I cautioned the arriero to keep close watch of the -Indian, for at one time I had caught on his face an expression of hatred -more intense than I had ever seen before. The plateau Indian of South -America is usually so stupid and docile that the unexpectedly venomous -look of the man after our friendly conversation and my good treatment -alarmed me. At the last moment, and when our backs were turned, our -Indian, under the screen of the packs, slipped away from us. The arriero -called out to know where he had gone. It took us but a few moments to -gain the top of a hill that commanded the valley. Fully a half-mile away -and almost indistinguishable against the brown of the valley floor was -our late assistant, running like a deer. No mule could follow over that -broken ground at an elevation of 16,000 feet, and so he escaped.</p> - -<p>Fortunately that afternoon we passed a half-grown boy riding back toward -Antabamba and he promised to hand the Governor a note in Spanish, -penciled on a leaf of my traverse book. I dropped all the polite phrases -that are usually employed and wrote as follows:</p> - -<div class="blockquot"> -<p class="nind">“Señor Gobernador:<br /> -</p> - -<p>“Your Indians have escaped, likewise the Lieutenant Governor. They -have taken two beasts. In the name of the Prefect of Abancay, I ask -you immediately to bring a fresh supply of men and animals. We -shall encamp near the first pass, three days west of Antabamba, -until you come.â€</p></div> - -<p>We were now without Indians to carry the instruments, which had -therefore to be strapped to the mules. Without guides we started -westward along the trail. At the next pass the topographer<a name="page_100" id="page_100"></a> rode to the -summit of a bluff and asked which of the two trails I intended to -follow. Just then a solitary Indian passed and I shouted back that I -would engage the Indian and precede the party, and he could tell from my -course at the fork of the trail how to direct his map and where to gain -camp at nightfall. But the Indian refused to go with us. All my -threatening was useless and I had to force myself to beat him into -submission with my quirt. Several repetitions on the way, when he -stubbornly refused to go further, kept our guide with us until we -reached a camp site. I had offered him a week’s pay for two hours’ work, -and had put coca and cigarettes into his hands. When these failed I had -to resort to force. Now that he was about to leave I gave him double the -amount I had promised him. He could scarcely believe his eyes. He rushed -up to the side of my mule, and reaching around my waist embraced me and -thanked me again and again. The plateau Indian is so often waylaid in -the mountains and impressed for service, then turned loose without pay -or actually robbed, that a <i>promise</i> to pay holds no attraction for him. -I had up to the last moment resembled this class of white. He was -astonished to find that I really meant to pay him well.</p> - -<p>Then he set out upon the return, faithfully delivering my note to the -topographer about the course of the trail and the position of the camp. -He had twelve miles to go to the first mountain hut, so that he could -not have traveled less than that distance to reach shelter. The next -morning a mantle of snow covered everything, yet when I pushed back the -tent flap there stood my scantily clad Indian of the night before, -shivering, with sandaled feet in the snow, saying that he had come back -to work for me!</p> - -<p>This camp was number thirteen out of Abancay, and here our topographer -was laid up for three days. Heretofore the elevation had had no effect -upon him, but the excessively lofty stations of the past few days and -the hard climbing had finally prostrated him. We had decided to carry -him out by the fourth day if he felt no better, but happily he recovered -sufficiently to continue the work. The delay enabled the Governor to -overtake us with a fresh<a name="page_101" id="page_101"></a> outfit. On the morning of our third day in -camp he overtook us with a small escort of soldiers accompanied by the -fugitive Teniente. He said that he had come to arrest me on the charge -of maltreating an official of Peru. A few packages of cigarettes and a -handful of raisins and biscuits so stirred his gratitude that we parted -the best of friends. Moreover he provided us with four fresh beasts and -four new men, and thus equipped we set out for a rendezvous about ten -miles away. But the faithless Governor turned off the trail and sought -shelter at the huts of a company of mountain shepherds. That night his -men slept on the ground in a bitter wind just outside our camp at 17,200 -feet. They complained that they had no food. The Governor had promised -to join us with llama meat for the peons. We fed them that night and -also the next day. But we had by that time passed the crest of the -western Cordillera and were outside the province of Antabamba. The next -morning not only our four men but also our four beasts were missing. We -were stranded and sick just under the pass. To add to our distress the -surgeon, Dr. Erving, was obliged to leave us for the return home, taking -the best saddle animal and the strongest pack mule. It was impossible to -go on with the map. That morning I rode alone up a side valley until I -reached a shepherd’s hut, where I could find only a broken-down, -shuffling old mule, perfectly useless for our hard work.</p> - -<p>Then there happened a piece of good luck that seems almost providential. -A young man came down the trail with three pack mules loaded with llama -meat. He had come from the Cotahuasi Valley the week before and knew the -trail. I persuaded him to let us hire one of his mules. In this way and -by leaving the instruments and part of our gear in the care of two -Indian youths we managed to get to Cotahuasi for rest and a new outfit.</p> - -<p>The young men who took charge of part of our outfit interested me very -greatly. I had never seen elsewhere so independent and clear-eyed a pair -of mountain Indians. At first they would have nothing to do with us. -They refused us permission to store our goods in their hut. To them we -were railroad engineers. They said that the railway might come and when -it did it would depopulate<a name="page_102" id="page_102"></a> the country. The railway was a curse. -Natives were obliged to work for the company without pay. Their uncle -had told them of frightful abuses over at Cuzco and had warned them not -to help the railway people in any way. They had moved out here in a -remote part of the mountains so that white men could not exploit them.</p> - -<p>In the end, however, we got them to understand the nature of our work. -Gifts of various sorts won their friendship, and they consented to guard -the boxes we had to leave behind. Two weeks later, on his return, the -topographer found everything unmolested.</p> - -<p>I could not but feel that the spirit of those strong and independent -young men was much better for Peru than the cringing, subservient spirit -of most of the Indians that are serfs of the whites. The policy of the -whites has been to suppress and exploit the natives, to abuse them, and -to break their spirit. They say that it keeps down revolution; it keeps -the Indian in his place. But certainly in other respects it is bad for -the Indian and it is worse for the whites. Their brutality toward the -natives is incredible. It is not so much the white himself as the -vicious half-breed who is often allied with him as his agent.</p> - -<p>I shall never forget the terror of two young girls driving a donkey -before them when they came suddenly face to face with our party, and we -at the same time hastily scrambled off our beasts to get a photograph of -a magnificent view disclosed at the bend of the steep trail. They -thought we had dismounted to attack them, and fled screaming in abject -fear up the mountain side, abandoning the donkey and the pack of -potatoes which must have represented a large part of the season’s -product. It is a kind of highway robbery condoned because it is only -robbing an Indian. He is considered to be lawful prey. His complaint -goes unnoticed. In the past a revolution has offered him sporadic -chances to wreak vengeance. More often it adds to his troubles by -scattering through the mountain valleys the desperate refugees or -lawless bands of marauders who kill the flocks of the mountain shepherds -and despoil their women.</p> - -<p>There are still considerable numbers of Indians who shun the<a name="page_103" id="page_103"></a> white man -and live in the most remote corners of the mountains. I have now and -again come upon the most isolated huts, invisible from the valley -trails. They were thatched with grass; the walls were of stone; the -rafters though light must have required prodigious toil, for all timber -stops at 12,000 feet on the mountain borders. The shy fugitive who -perches his hut near the lip of a hanging valley far above the trail may -look down himself unseen as an eagle from its nest. When the owner -leaves on a journey, or to take his flock to new pastures, he buries his -pottery or hides it in almost inaccessible caves. He locks the door or -bars it, thankful if the spoiler spares rafters and thatch.</p> - -<p>At length we reached Cotahuasi, a town sprawled out on a terrace just -above the floor of a deep canyon (<a href="#fig_29">Fig. 29</a>). Its flower gardens and -pastures are watered by a multitude of branching canals lined with low -willows. Its bright fields stretch up the lower slopes and alluvial fans -of the canyon to the limits of irrigation where the desert begins. The -fame of this charming oasis is widespread. The people of Antabamba and -Lambrama and even the officials of Abancay spoke of Cotahuasi as -practically the end of our journey. Fruits ripen and flowers blossom -every month of the year. Where we first reached the canyon floor near -Huaynacotas, elevation 11,500 feet (3,500 m.), there seemed to be acres -of rose bushes. Only the day before at an elevation of 16,800 feet -(5,120 m.) we had broken thick ice out of a mountain spring in order to -get water; now we were wading a shallow river, and grateful for the -shade along its banks. Thus we came to the town prepared to find the -people far above their plateau neighbors in character. Yet, in spite of -friendly priests and officials and courteous shopkeepers, there was a -spirit strangely out of harmony with the pleasant landscape.</p> - -<p>Inquiries showed that even here, where it seemed that only sylvan peace -should reign, there had recently been let loose the spirit of barbarism. -We shall turn to some of its manifestations and look at the reasons -therefor.</p> - -<p>In the revolution of 1911 a mob of drunken, riotous citizens gathered to -storm the Cotahuasi barracks and the jail. A full-blooded<a name="page_104" id="page_104"></a> Indian -soldier, on duty at the entrance, ordered the rioters to stop and when -they paid no heed he shot the leader and scattered the crowd. The -captain thereupon ordered the soldier to Arequipa because his life was -no longer safe outside the barracks. A few months later he was assigned -to Professor Bingham’s Coropuna expedition. Professor Bingham reached -the Cotahuasi Valley as I was about to leave it for the coast, and the -soldier was turned over to me so that he might leave Cotahuasi at the -earliest possible moment, for his enemies were plotting to kill him.</p> - -<p>He did not sleep at all the last night of his stay and had us called at -three in the morning. He told his friends that he was going to leave -with us, but that they were to announce his leaving a day later. In -addition, the Subprefect was to accompany us until daybreak so that no -harm might befall me while under the protection of a soldier who -expected to be shot from ambush.</p> - -<p>At four o’clock our whispered arrangements were made, we opened the -gates noiselessly, and our small cavalcade hurried through the -pitch-black streets of the town. The soldier rode ahead, his rifle -across his saddle, and directly behind him rode the Subprefect and -myself. The pack mules were in the rear. We had almost reached the end -of the street when a door opened suddenly and a shower of sparks flew -out ahead of us. Instantly the soldier struck spurs into his mule and -turned into a side street. The Subprefect drew his horse back savagely -and when the next shower of sparks flew out pushed me against the wall -and whispered: “Por Dios, quien es?†Then suddenly he shouted: “Sopla no -mas, sopla no mas†(stop blowing).</p> - -<p>Thereupon a shabby penitent man came to the door holding in his hand a -large tailor’s flatiron. The base of it was filled with glowing charcoal -and he was about to start his day’s work. The sparks were made in the -process of blowing through the iron to start the smoldering coals. We -greeted him with more than ordinary friendliness and passed on.</p> - -<p>At daybreak we had reached the steep western wall of the canyon where -the real ascent begins, and here the Subprefect turned back with many -<i>felicidades</i> for the journey and threats<a name="page_105" id="page_105"></a> for the soldier if he did not -look carefully after the pack train. From every angle of the zigzag -trail that climbs the “cuesta†the soldier scanned the valley road and -the trail below him. He was anxious lest news of his escape reach his -enemies who had vowed to take his life. Half the day he rode turned in -his saddle so as to see every traveler long before he was within harm’s -reach. By nightfall we safely reached Salamanca, fifty miles away (Fig. -62).</p> - -<p>The alertness of the soldier was unusual and I quite enjoyed his close -attention to the beasts and his total abstinence, for an alert and sober -soldier on detail is a rare phenomenon in the interior of Peru. But all -Salamanca was drunk when we arrived—Governor, alcaldes, citizens. Even -the peons drank up in brandy the money that we gave them for forage and -let the beasts starve. The only sober person I saw was the white -telegraph operator from Lima. He said that he had to stay sober, for the -telegraph office—the outward sign of government—was the special object -of attack of every drink-crazed gang of rioters. They had tried to break -in a few nights before and he had fired his revolver point-blank through -the door. The town offered no shelter but the dark filthy hut of the -Gobernador and the tiny telegraph office. So I made up my bed beside -that of the operator. We shared our meals and chatted until a late hour, -he recounting the glories of Lima, to which he hoped to return at the -earliest possible moment, and cursing the squalid town of Salamanca. His -operator’s keys were old, the batteries feeble, and he was in continual -anxiety lest a message could not be received. In the night he sprang out -of bed shouting frantically:</p> - -<p>“Estan llamando†(they are calling), only to stumble over my bed and -awaken himself and offer apologies for walking in his sleep.</p> - -<p>Meanwhile my soldier, having regained his courage, began drinking. It -was with great difficulty that I got started, after a day’s delay, on -the trail to Chuquibamba. There his thirst quite overcame him. To -separate him from temptation it became necessary to lock him up in the -village jail. This I did repeatedly on the way to Mollendo, except -beyond Quilca, where we slept in the<a name="page_106" id="page_106"></a> hot marshy valley out of reach of -drink, and where the mosquitoes kept us so busy that either eating or -drinking was almost out of the question.</p> - -<p>The drunken rioters of Cotahuasi and their debauched brothers at -Salamanca are chiefly natives of pure or nearly pure Indian blood. They -are a part of the great plateau population of the Peruvian Andes. Have -they degenerated to their present low state, or do they display merely -the normal condition of the plateau people? Why are they so troublesome -an element? To this as to so many questions that arise concerning the -highland population we find our answer not chiefly in government, or -religion, or inherited character, but in geography. I doubt very much if -a greater relative difference would be seen if two groups of whites were -set down, the one in the cold terrace lands of Salamanca, the other in -the warm vineyards of Aplao, in the Majes Valley. The common people of -these two towns were originally of the same race, but the lower valley -now has a white element including even most of those having the rank of -peons. Greater differences in character could scarcely be found between -the Aztecs and the Iroquois. In the warm valley there is of coarse -drunkenness, but it is far from general; there is stupidity, but the -people are as a whole alert; and finally, the climate and soil produce -grapes from which famous wines are made, they produce sugar cane, -cotton, and alfalfa, so that the whites have come in, diluted the Indian -blood, and raised the standard of life and behavior. Undoubtedly their -influence would tend to have the same general effect if they mixed in -equal numbers with the plateau groups. There is, however, a good reason -for their not doing so.</p> - -<p><a name="fig_62" id="fig_62"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_106a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_106a_sml.jpg" width="323" height="210" alt="Fig. 62—Salamanca, on the floor of the deep Arma Valley -(a tributary of one of the major coast valleys, the Ocoña), which is -really a canyon above this point and which, in spite of its steepness, -is thoroughly terraced and intensively cultivated up to the frost line." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 62—Salamanca, on the floor of the deep Arma Valley -(a tributary of one of the major coast valleys, the Ocoña), which is -really a canyon above this point and which, in spite of its steepness, -is thoroughly terraced and intensively cultivated up to the frost line.</p> -</div> - -<p><a name="fig_60" id="fig_60"></a></p> - -<p><a name="fig_61" id="fig_61"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_106b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_106b_sml.jpg" width="214" height="348" alt="Fig. 60—View across the Antabamba canyon just above -Huadquirca." /></a> -<br /> - -<p class="caption"><span class="smcap">Fig</span>. 60—View across the Antabamba canyon just above -Huadquirca.</p> - -<p class="caption"><span class="smcap">Fig. 61</span>—Huancarama, west of Abancay, on the famous Lima -to Buenos Aires road. Note the smooth slopes in the foreground. <a href="#CHAPTER_XI">See -Chapter XI</a>.</p> -</div> - -<p>The lofty towns of the plateau have a really wretched climate. White men -cannot live comfortably at Antabamba and Salamanca. Further, they are so -isolated that the modest comforts and the smallest luxuries of -civilization are very expensive. To pay for them requires a profitable -industry managed on a large scale and there is no such industry in the -higher valleys. The white who goes there must be satisfied to live like -an Indian. The result is easy to forecast. Outside of government -officers, only the dissolute<a name="page_107" id="page_107"></a> or unsuccessful whites live in the worst -towns, like Salamanca and Antabamba. A larger valley with a slightly -milder climate and more accessible situation, like Chuquibamba, will -draw a still better grade of white citizen and in the largest of -all—Cuzco and the Titicaca basin—we find normal whites in larger -numbers, though they nowhere live in such high ratios to the Indian as -on the coast and in the lower valleys near the coast. With few -exceptions the white population of Peru is distributed in response to -favorable combinations of climate, soil, accessibility, and general -opportunities to secure a living without extreme sacrifice.</p> - -<p>These facts are stated in a simple way, for I wish to emphasize the -statement that the Indian population responds to quite other stimuli. -Most of the luxuries and comforts of the whites mean nothing to the -Indian. The machine-made woolens of the importers will probably never -displace his homespun llama-wool clothing. His implements are few in -number and simple in form. His tastes in food are satisfied by the few -products of his fields and his mountain flocks. Thus he has lived for -centuries and is quite content to live today. Only coca and brandy tempt -him to engage in commerce, to toil now and then in the hot valleys, and -to strive for more than the bare necessities of life. Therefore it -matters very little to him if his home town is isolated, or the -resources support but a small group of people. He is so accustomed to a -solitary existence in his ramblings with his flocks that a village of -fifty houses offers social enjoyments of a high order. Where a white -perishes for lack of society the Indian finds himself contented. -Finally, he is not subject to the white man’s exploitation when he lives -in remote places. The pastures are extensive and free. The high valley -lands are apportioned by the alcalde according to ancient custom. His -life is unrestricted by anything but the common law and he need have no -care for the morrow, for the seasons here are almost as fixed as the -stars.</p> - -<p>Thus we have a sort of segregation of whites in the lower places where a -modern type of life is maintained and of Indians in the higher places -where they enjoy advantages that do not appeal to the whites. Above -8,000 feet the density of the white population<a name="page_108" id="page_108"></a> bears a close inverse -proportion to the altitude, excepting in the case of the largest valleys -whose size brings together such numbers as to tempt the commercial and -exploiting whites to live in them. Furthermore, we should find that high -altitude, limited size, and greater isolation are everywhere closely -related to increasing immorality or decreasing character among the -whites. So to the low Indian population there is thus added the lowest -of the white population. Moreover, because it yields the largest -returns, the chief business of these whites is the sale of coca and -brandy and the downright active debauchery of the Indian. This is all -the easier for them because the isolated Indian, like the average -isolated white, has only a low and provincial standard of morality and -gets no help from such stimulation as numbers usually excite.</p> - -<p>For example, the Anta basin at harvest time is one of the fairest sights -in Peru. Sturdy laborers are working diligently. Their faces are bright -and happy, their skin clear, their manner eager and animated. They sing -at their work or gather about their mild <i>chicha</i> and drink to the -patron saints of the harvest. The huts are filled with robust children; -all the yards are turned into threshing floors; and from the stubbly -hillslopes the shepherd blows shrill notes upon his barley reeds and -bamboo flute. There is drinking but there is little disorder and there -is always a sober remnant that exercises a restraining influence upon -the group.</p> - -<p>In the most remote places of all one may find mountain groups of a high -order of morality unaffected by the white man or actually shunning him. -Clear-eyed, thick-limbed, independent, a fine, sturdy type of man this -highland shepherd may be. But in the town he succumbs to the temptation -of drink. Some writers have tried to make him out a superior to the -plains and low valley type. He is not that. The well-regulated groups of -the lower elevations are far superior intellectually and morally in -spite of the fact that the poorly regulated groups may fall below the -highland dweller in morality. The coca-chewing highlander is a clod. -Surely, as a whole, the mixed breed of the coastal valleys is a far -worthier type, save in a few cases where a Chinese or negroid element or -both have led to local inferiority. And surely, also, that is the<a name="page_109" id="page_109"></a> worst -combination which results in adding the viciousness of the inferior or -debased white to the stupidity of the highland Indian. It is here that -the effects of geography are most apparent. If the white is tempted in -large numbers because of exceptional position or resources, as at La -Paz, the rule of altitude may have an exception. And other exceptions -there are not due to physical causes, for character is practically never -a question of geography alone. There is the spiritual factor that may -illumine a strong character and through his agency turn a weak community -into a powerful one, or hold a weakened group steadfast against the -forces of disintegration. Exceptions arise from this and other causes -and yet with them all in mind the geographic factor seems predominant in -the types illustrated herewith.<a name="FNanchor_17_17" id="FNanchor_17_17"></a><a href="#Footnote_17_17" class="fnanchor">[17]</a><a name="page_110" id="page_110"></a></p> - -<h3><a name="CHAPTER_VIII" id="CHAPTER_VIII"></a>CHAPTER VIII<br /><br /> -THE COASTAL DESERT</h3> - -<p>T<small>O</small> the wayfarer from the bleak mountains the warm green valleys of the -coastal desert of Peru seem like the climax of scenic beauty. The -streams are intrenched from 2,000 to 4,000 feet, and the valley walls in -some places drop 500 feet by sheer descents from one level to another. -The cultivated fields on the valley floors look like sunken gardens and -now and then one may catch the distant glint of sunlight on water. The -broad white path that winds through vineyards and cotton-fields, follows -the foot of a cliff, or fills the whole breadth of a gorge is the -waste-strewn, half-dry channel of the river. In some places almost the -whole floor is cultivated from one valley wall to the other. In other -places the fields are restricted to narrow bands between the river and -the impending cliffs of a narrow canyon. Where tributaries enter from -the desert there may be huge banks of mud or broad triangular fans -covered with raw, infertile earth. The picture is generally touched with -color—a yellow, haze-covered horizon on the bare desert above, brown -lava flows suspended on the brink of the valley, gray-brown cliffs, and -greens ranging from the dull shade of algarrobo, olive and fig trees, to -the bright shade of freshly irrigated alfalfa pastures.</p> - -<p>After several months’ work on the cold highlands, where we rode almost -daily into hailstorms or wearisome gales, we came at length to the -border of the valley country. It will always seem to me that the weather -and the sky conspired that afternoon to reward us for the months of toil -that lay behind. And certainly there could be no happier place to -receive the reward than on the brink of the lava plateau above -Chuquibamba. There was promise of an extraordinary view in the growing -beauty of the sky, and we hurried our tired beasts forward so that the -valley below<a name="page_111" id="page_111"></a> might also be included in the picture. The head of the -Majes Valley is a vast hollow bordered by cliffs hundreds of feet high, -and we reached the rim of it only a few minutes before sunset.</p> - -<p><a name="fig_63" id="fig_63"></a></p> - -<p><a name="fig_64" id="fig_64"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_110a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_110a_sml.jpg" width="217" height="319" alt="Fig. 63—The deep fertile Majes Valley below Cantas. -Compare with Fig. 6 showing the Chili Valley at Arequipa." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 63—The deep fertile Majes Valley below Cantas. -Compare with <a href="#fig_6">6</a> showing the Chili Valley at Arequipa.</p> - -<p class="caption"><span class="smcap">Fig. 64</span>—The Majes Valley, desert coast, western Peru. -The lighter patches on the valley floor are the gravel beds of the river -at high water. Much of the alluvial land is still uncleared.</p> -</div> - -<p>I remember that we halted beside a great wooden cross and that our -guide, dismounting, walked up to the foot of it and kissed and embraced -it after the custom of the mountain folk when they reach the head of a -steep “cuesta.†Also that the trail seemed to drop off like a stairway, -which indeed it was.<a name="FNanchor_18_18" id="FNanchor_18_18"></a><a href="#Footnote_18_18" class="fnanchor">[18]</a> Everything else about me was completely -overshadowed by snowy mountains, colored sky, and golden-yellow desert. -One could almost forget the dark clouds that gather around the great -mass of Coropuna and the bitter winds that creep down from its glaciers -at night—it seemed so friendly and noble. Behind it lay bulky masses of -rose-tinted clouds. We had admired their gay colors only a few minutes, -when the sun dropped behind the crest of the Coast Range and the last of -the sunlight played upon the sky. It fell with such marvelously swift -changes of color upon the outermost zone of clouds as these were shifted -with the wind that the eye had scarcely time to comprehend a tint before -it was gone and one more beautiful still had taken its place. The -reflected sunlight lay warm and soft upon the white peaks of Coropuna, -and a little later the Alpine glow came out delicately clear.</p> - -<p>When we turned from this brilliant scene to the deep valley, we found -that it had already become so dark that its greens had turned to black, -and the valley walls, now in deep shadow, had lost half their splendor. -The color had not left the sky before the lights of Chuquibamba began to -show, and candles twinkled from the doors of a group of huts close under -the cliff. We were not long in starting the descent. Here at last were -friendly habitations and happy people. I had worked for six weeks -between 12,000 and 17,000 feet, constantly ill from mountain sickness, -and it was with no regret that I at last left the plateau and got down<a name="page_112" id="page_112"></a> -to comfortable altitudes. It seemed good news when the guide told me -that there were mosquitoes in the marshes of Camaná. Any low, hot land -would have seemed like a health resort. I had been in the high country -so long that, like the Bolivian mining engineer, I wanted to get down -not only to sea level, but below it!</p> - -<p><a name="fig_65" id="fig_65"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_112_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_112_sml.jpg" width="210" height="121" alt="Fig. 65—Regional diagram to show the physical relations -in the coastal desert of Peru. For location, see Fig. 20." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 65—Regional diagram to show the physical relations -in the coastal desert of Peru. For location, see <a href="#fig_20">Fig. 20</a>.</p> -</div> - -<p>If the reader will examine Figs. 65 and 66, and the photographs that -accompany them, he may gain an idea of the more important features of -the coastal region. We have already described, in Chapters V and VII, -the character of the plateau region and its people. Therefore, we need -say little in this place of the part of the Maritime Cordillera that is -included in the figure. Its unpopulated rim (see p. <a href="#page_054">54</a>), the -semi-nomadic herdsmen and shepherds from Chuquibamba that scour its -pastures in the moist vales about Coropuna, and the gnarled and stunted -trees at 13,000 feet (3,960 m.) which partly supply Chuquibamba with -firewood, are its most important features. A few groups of huts just -under the snowline are inhabited for only a part of the year. The -delightful valleys are too near and tempting. Even a plateau Indian -responds to the call of a dry valley, however he may shun the moist, -warm valleys on the eastern border of the Cordillera.<a name="page_113" id="page_113"></a></p> - -<p><a name="fig_66" id="fig_66"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_113_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_113_sml.jpg" width="211" height="281" alt="Fig. 66—Irrigated and irrigable land of the coastal belt -of Peru. The map exhibits in a striking manner how small a part of the -whole Pacific slope is available for cultivation. Pasture grows over all -but the steepest and the highest portions of the Cordillera to the right -of (above) the dotted line. Another belt of pasture too narrow to show -on the map, grows in the fog belt on the seaward slopes of the Coast -Range. Scale, 170 miles to the inch." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 66—Irrigated and irrigable land of the coastal belt -of Peru. The map exhibits in a striking manner how small a part of the -whole Pacific slope is available for cultivation. Pasture grows over all -but the steepest and the highest portions of the Cordillera to the right -of (above) the dotted line. Another belt of pasture too narrow to show -on the map, grows in the fog belt on the seaward slopes of the Coast -Range. Scale, 170 miles to the inch.</p> -</div> - -<p><a name="page_114" id="page_114"></a></p> - -<p>The greater part of the coastal region is occupied by the desert. Its -outer border is the low, dry, gentle, eastward-facing slope of the Coast -Range. Its inner border is the foot of the steep descent that marks the -edge of the lava plateau. This descent is a fairly well-marked line, -here and there broken by a venturesome lava flow that extends far out -from the main plateau. Within these definite borders the desert extends -continuously northwestward for hundreds of miles along the coast of Peru -from far beyond the Chilean frontier almost to the border of Ecuador. It -is broken up by deep tranverse valleys and canyons into so-called -“pampas,†each of which has a separate name; thus west of Arequipa -between the Vitor and Majes valleys are the “Pampa de Vitor†and the -“Pampa de Sihuas,†and south of the Vitor is the “Pampa de Islay.â€</p> - -<p>The pampa surfaces are inclined in general toward the sea. They were -built up to their present level chiefly by mountain streams before the -present deep valleys were cut, that is to say, when the land was more -than a half-mile lower. Some of their material is wind-blown and on the -walls of the valleys are alternating belts of wind-blown and water-laid -strata from one hundred to four hundred feet thick as if in past ages -long dry and long wet periods had succeeded each other. The wind has -blown sand and dust from the desert down into the valleys, but its chief -work has been to drive the lighter desert waste up partly into the -mountains and along their margins, partly so high as to carry it into -the realm of the lofty terrestrial winds, whence it falls upon surfaces -far distant from the fields of origin. There are left behind the heavier -sand which the wind rolls along on the surfaces and builds into -crescentic dunes called médanos, and the pebbles that it can sandpaper -but cannot remove bodily. Thus there are belts of dunes, belts of -irregular sand drifts, and belts of true desert “pavement†(a residual -mantle of faceted pebbles and irregular stones).</p> - -<div class="figcenter"> -<a href="images/ill_page_114a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_114a_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_114a_sml.jpg" width="364" height="417" alt="THE YALE PERUVIAN EXPEDITION OF 1911 -HIRAM BINGHAM, DIRECTOR -CAMANà QUADRANGLE -(Aplao)" /> -</div> - -<p>Yet another feature of the desert pampa are the “dry†valleys that join -the through-flowing streams at irregular intervals, as shown in the -accompanying regional diagram. If one follow<a name="page_115" id="page_115"></a> a dry valley to its head -he will find there a set of broad and shallow tributaries. Sand drifts -may clog them and appear to indicate that water no longer flows through -them. They are often referred to by unscientific travelers as evidences -of a recent change of climate. I had once the unusual opportunity (in -the mountains of Chile) of seeing freshly fallen snow melted rapidly and -thus turned suddenly into the streams. In 1911 this happened also at San -Pedro de Atacama, northern Chile, right in the desert at 8,000 feet -(2,440 m.) elevation, and in both places the dry, sand-choked valleys -were cleaned out and definite channels reëstablished. From a large -number of facts like these we know that the dry valleys represent the -work of the infrequent rains. No desert is absolutely rainless, although -until recently it was the fashion to say so. Naturally the wind, which -works incessantly, partly offsets the work of the water. Yet the wind -can make but little impression upon the general outlines of the dry -valleys. They remain under the dominance of the irregular rains. These -come sometimes at intervals of three or four years, again at intervals -of ten to fifteen years, and some parts of the desert have probably been -rainless for a hundred years. Some specific cases are discussed in the -chapter on Climate.</p> - -<p>The large valleys of the desert zone have been cut by snow-fed streams -and then partly filled again so that deep waste lies on their floors and -abuts with remarkable sharpness against the bordering cliffs (<a href="#fig_155">Fig. 155</a>). -Extensive flats are thus available for easy cultivation, and the -through-flowing streams furnish abundant water to the irrigating canals. -The alluvial floor begins almost at the foot of the steep western slope -of the lava plateau, but it is there stony and coarse—hence -Chuquibamba, or plain of stones (chuqui = stone; bamba = plain). Farther -down and about half-way between Chuquibamba and Aplao (Camaná -Quadrangle) it is partly covered with fresh mud and sand flows from the -bordering valley walls and the stream is intrenched two hundred feet. A -few miles above Aplao the stream emerges from its narrow gorge and -thenceforth flows on the surface of the alluvium right to the sea. -Narrow places occur between Cantas and Aplao, where there is a -projection<a name="page_116" id="page_116"></a> of old and hard quartzitic rock, and again above Camaná, -where the stream cuts straight across the granite axis of the Coast -Range. Elsewhere the rock is either a softer sandstone or still -unindurated sands and gravels, as at the top of the desert series of -strata that are exposed on the valley wall. The changing width of the -valley is thus a reflection of the changing hardness of the rock.</p> - -<p>There is a wide range of products between Chuquibamba at 10,000 feet -(3,050 m.) at the head of the valley and Camaná near the valley mouth. -At the higher levels fruit will not grow—only alfalfa, potatoes, and -barley. A thousand feet below Chuquibamba fruit trees appear. Then -follows a barren stretch where there are mud flows and where the river -is intrenched. Below this there is a wonderful change in climate and -products. The elevation falls off 4,000 feet and the first cultivated -patches below the middle unfavorable section are covered with grape -vines. Here at 3,000 feet (900 m.) elevation above the sea begin the -famous vineyards of the Majes Valley, which support a wine industry that -dates back to the sixteenth century. Some of the huge buried earthenware -jars for curing the wine at Hacienda Cantas were made in the reign of -Philip II.</p> - -<p>The people of Aplao and Camaná are among the most hospitable and -energetic in Peru, as if these qualities were but the reflection of the -bounty of nature. Nowhere could I see evidences of crowding or of the -degeneracy or poverty that is so often associated with desert people. -Water is always plentiful; sometimes indeed too plentiful, for floods -and changes in the bed of the river are responsible for the loss of a -good deal of land. This abundance of water means that both the small and -the large landowners receive enough. There are none of the troublesome -official regulations, as in the poorer valleys with their inevitable -favoritism or downright graft. Yet even here the valley is not fully -occupied; at many places more land could be put under cultivation. The -Belaunde brothers at Cantas have illustrated this in their new cotton -plantation, where clearings and new canals have turned into cultivated -fields tracts long covered with brush.<a name="page_117" id="page_117"></a></p> - -<p>The Majes Valley sorely lacks an adequate port. Its cotton, sugar, and -wine must now be shipped to Camaná and thence to Mollendo, either by a -small bi-weekly boat, or by pack-train over the coast trail to Quilca, -where ocean steamers call. This is so roundabout a way that the planters -of the mid-valley section and the farmers of the valley head now export -their products over the desert trail from Cantas to Vitor on the -Mollendo-Arequipa railroad, whence they can be sent either to the cotton -mills or the stores of Arequipa, the chief distributing market of -southern Peru, or to the ocean port.</p> - -<p>The foreshore at Camaná is low and marshy where the salt water covers -the outer edge of the delta. In the hollow between two headlands a broad -alluvial plain has been formed, through which the shallow river now -discharges. Hence the natural indentation has been filled up and the -river shoaled. To these disadvantages must be added a third, the -shoaling of the sea bottom, which compels ships to anchor far off shore. -Such shoals are so rare on this dry and almost riverless coast as to be -a menace to navigation. The steamer <i>Tucapelle</i>, like all west-coast -boats, was sailing close to the unlighted shore on a very dark night in -April, 1911, when the usual fog came on. She struck the reef just off -Camaná. Half of her passengers perished in trying to get through the -tremendous surf that broke over the bar. The most practicable scheme for -the development of the port would seem to be a floating dock and tower -anchored out of reach of the surf, and connected by cable with a railway -on shore. Harbor works would be extraordinarily expensive. The valley -can support only a modest project.</p> - -<p>The relations of <a href="#fig_65">65</a> , representing the Camaná-Vitor region, are -typical of southern Peru, with one exception. In a few valleys the -streams are so small that but little water is ever found beyond the foot -of the mountains, as at Moquegua. In the Chili Valley is Arequipa (8,000 -feet), right at the foot of the big cones of the Maritime Cordillera -(see Fig. <a href="#fig_6">6</a>). The green valley floor narrows rapidly and cultivation -disappears but a few miles below the town. Outside the big valleys -cultivation is limited to the best<a name="page_118" id="page_118"></a> spots along the foot of the Coast -Range, where tiny streams or small springs derive water from the zone of -clouds and fogs on the seaward slopes of the Coast Range. Here and there -are olive groves, a vegetable garden, or a narrow alfalfa meadow, -watered by uncertain springs that issue below the hollows of the -bordering mountains.</p> - -<p><a name="fig_67" id="fig_67"></a></p> -<p><a name="fig_68" id="fig_68"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_118_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_118_sml.jpg" width="207" height="173" alt="Fig. 67—Irrigated and irrigable land in the Ica Valley -of the coastal desert of Peru." /></a> -<br /> - -<table border="0" cellpadding="5" cellspacing="0" summary=""> -<tr valign="top"><td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 67—Irrigated and irrigable land in the Ica Valley -of the coastal desert of Peru.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig. 68</span>—The projected canal to convey water from the -Atlantic slope to the Pacific slope of the Maritime Cordillera.<a name="FNanchor_19_19" id="FNanchor_19_19"></a><a href="#Footnote_19_19" class="fnanchor">[19]</a></p></td></tr> -</table> -</div> - -<p>In central and northern Peru the coastal region has aspects quite -different from those about Camaná. At some places, for example north of -Cerro Azul, the main spurs of the Cordillera extend down to the shore. -There is neither a low Coast Range nor a broad desert pampa. In such -places flat land is found only on the alluvial fans and deltas. Lima and -Callao are typical. <a href="#fig_66">66</a> , compiled from Adams’s reports on the water -resources of<a name="page_119" id="page_119"></a> the coastal region of Peru, shows this distinctive feature -of the central region. Beyond Salaverry extends the northern region, -where nearly all the irrigated land is found some distance back from the -shore. The farther north we go the more marked is this feature, because -the coastal belt widens. Catacaos is several miles from the sea, and -Piura is an interior place. At the extreme north, where the rains begin, -as at Tumbez, the cultivated land once more extends to the coast.</p> - -<p><a name="fig_69" id="fig_69"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_119a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_119a_sml.jpg" width="211" height="52" alt="Fig. 69—A stream of the intermittent type in the coastal -desert of Peru. Depth of water in the Puira River at Puira, 1905. (Bol. -de Minas del Perú, 1906, No. 45, p. 2.)" /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 69—A stream of the intermittent type in the coastal -desert of Peru. Depth of water in the Puira River at Puira, 1905. (Bol. -de Minas del Perú, 1906, No. 45, p. 2.)</p> -</div> - -<p><a name="fig_70" id="fig_70"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_119b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_119b_sml.jpg" width="211" height="73" alt="Fig. 70—A stream of the perennial type in the coastal -desert of Peru. Depth of water in the Chira River at Sullana, 1905. Data -from May to September are approximate. (Bol. de Minas del Perú, 1906, -No. 45, p. 2.)" /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 70—A stream of the perennial type in the coastal -desert of Peru. Depth of water in the Chira River at Sullana, 1905. Data -from May to September are approximate. (Bol. de Minas del Perú, 1906, -No. 45, p. 2.)</p> -</div> - -<p>These three regions contain all the fertile coastal valleys of Peru. The -larger ones are impressive—with cities, railways, ports, and land in a -high state of cultivation. But they are after all only a few hundred -square miles in extent. They contain less than a quarter of the people. -The whole Pacific slope from the crest of the Cordillera has about -15,000 square miles (38,850 sq. km.), and of this only three per cent is -irrigated valley land, as shown in <a href="#fig_66">66</a> . Moreover, only a small -additional amount may be irrigated, perhaps one half of one per cent. -Even this amount<a name="page_120" id="page_120"></a> may be added not only by a better use of the water but -also by the diversion of streams and lakes from the Atlantic to the -Pacific. Figs. 67 and 68 represent such a project, in which it is -proposed to carry the water of Lake Choclococha through a canal and -tunnel under the continental divide and so to the head of the Ica -Valley. A little irrigation can be and is carried on by the use of well -water, but this will never be an important source because of the great -depth to the ground water, and the fact that it, too, depends ultimately -upon the limited rains.</p> - -<p>The inequality of opportunity in the various valleys of the coastal -region depends in large part also upon inequality of river discharge. -This is dependent chiefly upon the sources of the streams, whether in -snowy peaks of the main Cordillera with fairly constant run-off, or in -the western spurs where summer rains bring periodic high water. A third -type has high water during the time of greatest snow melting, combined -with summer rains, and to this class belongs the Majes Valley with its -sources in the snow-cap of Coropuna. The other two types are illustrated -by the accompanying diagrams for Puira and Chira, the former -intermittent in flow, the latter fairly constant.<a name="FNanchor_20_20" id="FNanchor_20_20"></a><a href="#Footnote_20_20" class="fnanchor">[20]</a></p> - -<div class="figcenter"> -<a href="images/ill_page_120a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_120a_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_120a_sml.jpg" width="375" height="411" alt="THE YALE PERUVIAN EXPEDITION OF 1911 - -HIRAM BINGHAM DIRECTOR - -APLAO QUADRANGLE" /> -</div> - -<p><a name="page_121" id="page_121"></a></p> - -<h3><a name="CHAPTER_IX" id="CHAPTER_IX"></a>CHAPTER IX<br /><br /> -CLIMATOLOGY OF THE PERUVIAN ANDES</h3> - -<h4>CLIMATIC BELTS</h4> - -<p>The noble proportions of the Peruvian Andes and their position in -tropical latitudes have given them climatic conditions of great -diversity. Moreover, their great breadth and continuously lofty summits -have distributed the various climatic types over spaces sufficiently -ample to affect large and important groups of people. When we add to -this the fact that the topographic types developed on a large scale are -distributed at varying elevations, and that upon them depend to a large -degree the chief characteristics of the soil, another great factor in -human distribution, we are prepared to see that the Peruvian Andes -afford some striking illustrations of combined climatic and topographic -control over man.</p> - -<p>The topographic features in their relations to the people have been -discussed in preceding chapters. We shall now examine the corresponding -effects of climate. It goes without saying that the topographic and -climatic controls cannot and need not be kept rigidly apart. Yet it -seems desirable, for all their natural interdependence, to give them -separate treatment, since the physical laws upon which their -explanations depend are of course entirely distinct. Further, there is -an independent group of human responses to detailed climatic features -that have little or no connection with either topography or soil.</p> - -<p>The chief climatic belts of Peru run roughly from north to south in the -direction of the main features of the topography. Between 13° and 18° -S., however, the Andes run from northwest to southeast, and in short -stretches nearly west-east, with the result that the climatic belts -likewise trend westward, a condition well illustrated on the -seventy-third meridian. Here are developed<a name="page_122" id="page_122"></a> important climatic features -not found elsewhere in Peru. The trade winds are greatly modified in -direction and effects; the northward-trending valleys, so deep as to be -secluded from the trades, have floors that are nearly if not quite arid; -a restricted coastal region enjoys a heavier rainfall; and the snowline -is much more strongly canted from west to east than anywhere else in the -long belt of mountains from Patagonia to Venezuela. These exceptional -features depend, however, upon precisely the same physical laws as the -normal climatic features of the Peruvian Andes. They can, therefore, be -more easily understood after attention has been given to the larger -aspects of the climatic problem of which they form a part.</p> - -<p>The critical relations of trade winds, lofty mountains, and ocean -currents that give distinction to Peruvian climate are shown in Figs. 71 -to 73. From them and <a href="#fig_74">74</a> it is clear that the two sides of the -Peruvian mountains are in sharp contrast climatically. The eastern -slopes have almost daily rains, even in the dry season, and are clothed -with forest. The western leeward slopes are so dry that at 8,000 feet -even the most drought-resisting grasses stop—only low shrubs live below -this level, and over large areas there is no vegetation whatever. An -exception is the Coast Range, not shown on these small maps, but -exhibited in the succeeding diagram. These have moderate rains on their -seaward (westerly) slopes during some years and grass and shrubby -vegetation grow between the arid coastal terraces below them and the -parched desert above. The greatest variety of climate is enjoyed by the -mountain zone. Its deeper valleys and basins descend to tropical levels; -its higher ranges and peaks are snow-covered. Between are the climates -of half the world compressed, it may be, between 6,000 and 15,000 feet -of elevation and with extremes only a day’s journey apart.</p> - -<p><a name="fig_71" id="fig_71"></a></p> - -<p><a name="fig_72" id="fig_72"></a></p> -<p><a name="fig_73" id="fig_73"></a></p> -<p><a name="fig_74" id="fig_74"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_123_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_123_sml.jpg" width="216" height="297" alt="Fig. 71—The three chief topographic regions of Peru." /></a> -<br /> -<p class="caption">Fig. 71—The three chief topographic regions of Peru.<br /> -<span class="smcap">Fig. 72</span>—The wind belts of Peru and ocean currents of -adjacent waters.<br /> -<span class="smcap">Fig. 73</span>—The climatic belts of Peru.<br /> -<span class="smcap">Fig. 74</span>—Belts of vegetation in Peru.</p> -</div> - -<p>In the explanation of these contrasts we have to deal with relatively -simple facts and principles; but the reader who is interested chiefly in -the human aspects of the region should turn to p. <a href="#page_138">138</a> where the effects -of the climate on man are set forth. The ascending trades on the eastern -slopes pass successively into<a name="page_123" id="page_123"></a><a name="page_124" id="page_124"></a> atmospheric levels of diminishing -pressure; hence they expand, deriving the required energy for expansion -from the heat of the air itself. The air thereby cooled has a lower -capacity for the retention of water vapor, a function of its -temperature; the colder the air the less water vapor it can take up. As -long as the actual amount of water vapor in the air is less than that -which the air can hold, no rain falls. But the cooling process tends -constantly to bring the warm, moist, ascending air currents to the limit -of their capacity for water vapor by diminishing the temperature. -Eventually the air is saturated and if the capacity diminishes still -further through diminishing temperature some of the water vapor must be -condensed from a gaseous to a liquid form and be dropped as rain.</p> - -<p>The air currents that rise thousands of feet per day on the eastern -slopes of the Andes pass again and again through this practically -continuous process and the eastern aspect of the mountains is kept -rain-soaked the whole year round. For the trades here have only the -rarest reversals. Generally they blow from the east day after day and -repeat a fixed or average type of weather peculiar to that part of the -tropics under their steady domination. During the southern summer, when -the day-time temperature contrasts between mountains and plains are -strongest, the force of the trade wind is greatly increased and likewise -the rapidity of the rain-making processes. Hence there is a distinct -seasonal difference in the rainfall—what we call, for want of a better -name, a “wet†and a “dry†season.</p> - -<p>On the western or seaward slopes of the Peruvian Andes the trade winds -descend, and the process of rain-making is reversed to one of -rain-taking. The descending air currents are compressed as they reach -lower levels where there are progressively higher atmospheric pressures. -The energy expended in the process is expressed in the air as heat, -whence the descending air gains steadily in temperature and capacity for -water vapor, and therefore is a drying wind. Thus the leeward, western -slopes of the mountains receive little rain and the lowlands on that -side are desert.<a name="page_125" id="page_125"></a></p> - -<h4>THE CLIMATE OF THE COAST</h4> - -<p>A series of narrow but pronounced climatic zones coincide with the -topographic subdivisions of the western slope of the country between the -crest of the Maritime Cordillera and the Pacific Ocean. This belted -arrangement is diagrammatically shown in <a href="#fig_75">75</a> . From the zone of lofty -mountains with a well-marked summer rainy season descent is made by -lower slopes with successively less and less precipitation to the desert -strip, where rain is only known at irregular intervals of many years’ -duration. Beyond lies the seaward slope of the Coast Range, more or less -constantly enveloped in fog and receiving actual rain every few years, -and below it is the very narrow band of dry coastal terraces.</p> - -<p><a name="fig_75" id="fig_75"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_125_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_125_sml.jpg" width="210" height="46" alt="Fig. 75—Topographic and climatic provinces in the -coastal region of Peru. The broadest division, into the zones of regular -annual rains and of irregular rains, occurs approximately at 8,000 feet -but is locally variable. To the traveler it is always clearly defined by -the change in architecture, particularly of the house roofs. Those of -the coast are flat; those of the sierra are pitched to facilitate run -off." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 75—Topographic and climatic provinces in the -coastal region of Peru. The broadest division, into the zones of regular -annual rains and of irregular rains, occurs approximately at 8,000 feet -but is locally variable. To the traveler it is always clearly defined by -the change in architecture, particularly of the house roofs. Those of -the coast are flat; those of the sierra are pitched to facilitate run -off.</p> -</div> - -<p>The basic cause of the general aridity of the region has already been -noted; the peculiar circumstances giving origin to the variety in detail -can be briefly stated. They depend upon the meteorologic and -hydrographic features of the adjacent portion of the South Pacific Ocean -and upon the local topography.</p> - -<p>The lofty Andes interrupt the broad sweep of the southeast trades -passing over the continent from the Atlantic; and the wind circulation -of the Peruvian Coast is governed to a great degree by the high pressure -area of the South Pacific. The prevailing winds blow from the south and -the southeast, roughly paralleling the coast or, as onshore winds, -making a small angle with it. When the Pacific high pressure area is -best developed (during the southern winter), the southerly direction of -the winds is emphasized,<a name="page_126" id="page_126"></a> a condition clearly shown on the Pilot Charts -of the South Pacific Ocean, issued by the U.S. Hydrographic Office.</p> - -<p><a name="fig_76" id="fig_76"></a></p> - -<div class="figleft" style="width: 111px;"> -<a href="images/ill_page_126_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_126_sml.jpg" width="111" height="106" alt="Fig. 76—Temperatures at Callao, June-September, 1912, -from observations taken by Captain A. Taylor, of Callao. Air -temperatures are shown by heavy lines; sea temperatures by light lines. -In view of the scant record for comparative land and water temperatures -along the Peruvian coast this record, short as it is, has special -interest." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 76—Temperatures at Callao, June-September, 1912, -from observations taken by Captain A. Taylor, of Callao. Air -temperatures are shown by heavy lines; sea temperatures by light lines. -In view of the scant record for comparative land and water temperatures -along the Peruvian coast this record, short as it is, has special -interest.</p> -</div> - -<p>The hydrographic feature of greatest importance is the Humboldt Current. -To its cold waters is largely due the remarkably low temperatures of the -coast.<a name="FNanchor_21_21" id="FNanchor_21_21"></a><a href="#Footnote_21_21" class="fnanchor">[21]</a> In the latitude of Lima its mean surface temperature is about -10° below normal. Lima itself has a mean annual temperature 4.6° F. -below the theoretical value for that latitude, (12° S.). An accompanying -curve shows the low temperature of Callao during the winter months. From -mid-June to mid-September the mean was 61° F., and the annual mean is -only 65.6° F. (18° C.). The reduction in temperature is accompanied by a -reduction in the vapor capacity of the super-incumbent air, an effect of -which much has been made in explanation of the west-coast desert. That -it is a contributing though not exclusive factor is demonstrated in Fig. -77. Curve <i>A</i> represents the hypothetical change of temperature on a -mountainous coast with temporary afternoon onshore winds from a <i>warm</i> -sea. Curve <i>B</i> represents the change of temperature if the sea be cold -(actual case of Peru). The more rapid rise of curve <i>B</i> to the right of -X-X′, the line of transition, and its higher elevation above its former -saturation level, as contrasted with <i>A</i>, indicates greater dryness -(lower relative humidity). There has been precipitation in case <i>A</i>, but -at a higher temperature, hence<a name="page_127" id="page_127"></a> more water vapor remains in the air -after precipitation has ceased. Curve <i>B</i> ultimately rises nearly to the -level of <i>A</i>, for with less water vapor in the air of case <i>B</i> the -temperature rises more rapidly (a general law). Moreover, the higher the -temperature the greater the radiation. To summarize, curve <i>A</i> rises -more slowly than curve <i>B</i>, (1) because of the greater amount of water -vapor it contains, which must have its temperature raised with that of -the air, and thus absorbs energy which would otherwise go to increase -the temperature of the air, and (2) because its loss of heat by -radiation is more rapid on account of its higher temperature. We -conclude from these principles and deductions that under the given -conditions a cold current intensifies, but does not cause the aridity of -the west-coast desert.</p> - -<p><a name="fig_77" id="fig_77"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_127_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_127_sml.jpg" width="210" height="75" alt="Fig. 77—To show progressive lowering of saturation -temperature in a desert under the influence of the mixing process -whereby dry and cool air from aloft sinks to lower levels thus -displacing the warm surface air of the desert. The evaporated moisture -of the surface air is thus distributed through a great volume of upper -air and rain becomes increasingly rarer. Applied to deserts in general -it shows that the effect of any cosmic agent in producing climatic -change from moist to dry or dry to moist will be disproportionately -increased. The shaded areas C and C’ represent the fog-covered slopes of -the Coast Range of Peru as shown in Fig. 92. X-X’ represents the crest -of the Coast Range." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 77—To show progressive lowering of saturation -temperature in a desert under the influence of the mixing process -whereby dry and cool air from aloft sinks to lower levels thus -displacing the warm surface air of the desert. The evaporated moisture -of the surface air is thus distributed through a great volume of upper -air and rain becomes increasingly rarer. Applied to deserts in general -it shows that the effect of any cosmic agent in producing climatic -change from moist to dry or dry to moist will be disproportionately -increased. The shaded areas C and C’ represent the fog-covered slopes of -the Coast Range of Peru as shown in <a href="#fig_92">Fig. 92</a>. X-X’ represents the crest -of the Coast Range.</p> -</div> - -<p>Curves <i>a</i> and <i>b</i> represent the rise of temperature in two contrasted -cases of warm and cold sea with the coastal mountains eliminated, so as -to simplify the principle applied to <i>A</i> and <i>B</i>. The steeper gradient -of <i>b</i> also represents the fact that the lower the initial temperature -the dryer will the air become in passing over the warm land. For these -two curves the transition line X-X’ coincides with the crest of the -Coast Range. It will also be seen that curve <i>a</i> is never so far from -the saturation level as<a name="page_128" id="page_128"></a><a name="page_129" id="page_129"></a> curve <i>b</i>. Hence, unusual atmospheric -disturbances would result in heavier and more frequent showers.</p> - -<p><a name="fig_78" id="fig_78"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_128_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_128_sml.jpg" width="219" height="349" alt="Fig. 78—Wind roses for Callao. The figures for the -earlier period (1897-1900) are drawn from data in the BoletÃn de la -Sociedad Geográfica de Lima, Vols. 7 and 8, 1898-1900: for the latter -period data from observations of Captain A. Taylor, of Callao. The -diameter of the circle represents the proportionate number of -observations when calm was registered." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 78—Wind roses for Callao. The figures for the -earlier period (1897-1900) are drawn from data in the BoletÃn de la -Sociedad Geográfica de Lima, Vols. 7 and 8, 1898-1900: for the latter -period data from observations of Captain A. Taylor, of Callao. The -diameter of the circle represents the proportionate number of -observations when calm was registered.</p> -</div> - -<p><a name="fig_79" id="fig_79"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_129_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_129_sml.jpg" width="215" height="179" alt="Fig. 79—Wind roses for Mollendo. The figures are drawn -from data in Peruvian Meteorology (1892-1895), Annals of the -Astronomical Observatory of Harvard College, Vol. 30, Pt. 2, Cambridge, -Mass., 1906. Observations for an earlier period, Feb. 1889-March 1890, -(Id. Vol. 39, Pt. 1, Cambridge, Mass. 1890) record S. E. wind at 2 p. m. -97 per cent of the observation time." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 79—Wind roses for Mollendo. The figures are drawn -from data in Peruvian Meteorology (1892-1895), Annals of the -Astronomical Observatory of Harvard College, Vol. 30, Pt. 2, Cambridge, -Mass., 1906. Observations for an earlier period, Feb. 1889-March 1890, -(Id. Vol. 39, Pt. 1, Cambridge, Mass. 1890) record S. E. wind at 2 p. m. -97 per cent of the observation time.</p> -</div> - -<p><a name="fig_80" id="fig_80"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_130_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_130_sml.jpg" width="208" height="178" alt="Fig. 80—Wind roses for the summer and winter seasons of -the years 1911-1913. The diameter of the circle in each case shows the -proportion of calm. Figures are drawn from data in the Anuario -Meteorológico de Chile, Publications No. 3, (1911), 6 (1912) and 13 -(1913), Santiago, 1912, 1914, 1914." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 80—Wind roses for the summer and winter seasons of -the years 1911-1913. The diameter of the circle in each case shows the -proportion of calm. Figures are drawn from data in the Anuario -Meteorológico de Chile, Publications No. 3, (1911), 6 (1912) and 13 -(1913), Santiago, 1912, 1914, 1914.</p> -</div> - -<p>Turning now to local factors we find on the west coast a regional -topography that favors a diurnal periodicity of air movement. The strong -slopes of the Cordillera and the Coast Range create up-slope or eastward -air gradients by day and opposite gradients by night. To this -circumstance, in combination with the low temperature of the ocean water -and the direction of the prevailing winds, is due the remarkable -development of the sea-breeze, without exception the most important -meteorological feature of the Peruvian Coast. Several graphic -representations are appended to show the dominance of the sea-breeze -(see wind roses<a name="page_130" id="page_130"></a> for Callao, Mollendo, Arica, and Iquique), but interest -in the phenomenon is far from being confined to the theoretical. -Everywhere along the coast the <i>virazon</i>, as the sea-breeze is called in -contradistinction to the <i>terral</i> or land-breeze, enters deeply into the -affairs of human life. According to its strength it aids or hinders -shipping; sailing boats may enter port on it or it may be so violent, -as, for example, it commonly is at Pisco, that cargo cannot be loaded or -unloaded during the afternoon. On the nitrate pampa of northern Chile -(20° to 25° S.) it not infrequently breaks with a roar that heralds its -coming an hour in advance. In the Majes Valley (12° S.) it blows gustily -for a half-hour and about noon (often by eleven o’clock) it settles down -to an uncomfortable gale. For an hour or two<a name="page_131" id="page_131"></a> before the sea-breeze -begins the air is hot and stifling, and dust clouds hover about the -traveler. The maximum temperature is attained at this time and not -around 2.00 <span class="smcap">P. M.</span> as is normally the case. Yet so boisterous is the noon -wind that the laborers time their siesta by it, and not by the high -temperatures of earlier hours. In the afternoon it settles down to a -steady, comfortable, and dustless wind, and by nightfall the air is once -more calm.</p> - -<p><a name="fig_81" id="fig_81"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_131_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_131_sml.jpg" width="214" height="167" alt="Fig. 81—Wind roses for Iquique for the summer and winter -seasons of the years 1911-1913. The diameter of the circle in each case -shows the proportion of calm. For source of data see Fig. 80." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 81—Wind roses for Iquique for the summer and winter -seasons of the years 1911-1913. The diameter of the circle in each case -shows the proportion of calm. For source of data see Fig. <a href="#fig_80">80</a>.</p> -</div> - -<p>Of highest importance are the effects of the sea-breeze on -precipitation. The bold heights of the Coast Range force the nearly or -quite saturated air of the sea-wind to rise abruptly several thousand -feet, and the adiabatic cooling creates fog, cloud, and even rain on the -seaward slope of the mountains. The actual form and amount of -precipitation both here and in the interior region vary greatly, -according to local conditions and to season and also from year to year. -The coast changes height and contour from<a name="page_132" id="page_132"></a> place to place. At Arica the -low coastal chain of northern Chile terminates at the Morro de Arica. -Thence northward is a stretch of open coast, with almost no rainfall and -little fog. But in the stretch of coast between Mollendo and the Majes -Valley a coastal range again becomes prominent. Fog enshrouds the hills -almost daily and practically every year there is rain somewhere along -their western aspect.</p> - -<p><a name="fig_82" id="fig_82"></a></p> - -<p><a name="fig_83" id="fig_83"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_132_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_132_sml.jpg" width="210" height="30" alt="Fig. 82—The wet and dry seasons of the Coast Range and -the Cordillera are complementary in time. The “wet†season of the former -occurs during the southern winter; the cloud bank on the seaward slopes -of the hills is best developed at that time and actual rains may occur." /></a> -<br /> - -<table border="0" cellpadding="5" cellspacing="0" summary=""> -<tr valign="top"><td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 82—The wet and dry seasons of the Coast Range and -the Cordillera are complementary in time. The “wet†season of the former -occurs during the southern winter; the cloud bank on the seaward slopes -of the hills is best developed at that time and actual rains may occur.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig. 83</span>—During the southern summer the seaward slopes of -the Coast Range are comparatively clear of fog. Afternoon cloudiness is -characteristic of the desert and increases eastward (compare <a href="#fig_86">86</a> ), -the influence of the strong sea winds as well as that of the trades -(compare <a href="#fig_93">93</a> B) being felt on the lower slopes of the Maritime -Cordillera.</p></td></tr></table> -</div> - -<p>During the southern winter the cloud bank of the coast is best developed -and precipitation is greatest. At Lima, for instance, the clear skies of -March and April begin to be clouded in May, and the cloudiness grows -until, from late June to September, the sun is invisible for weeks at a -time. This is the period of the garua (mist) or the “tiempo de lomas,†-the “season of the hills,†when the moisture clothes them with verdure -and calls thither the herds of the coast valleys.</p> - -<p><a name="fig_84" id="fig_84"></a></p> - -<div class="figright" style="width: 116px;"> -<a href="images/ill_page_133_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_133_sml.jpg" width="116" height="180" alt="Fig. 84—Cloudiness at Callao. Figures are drawn from -data in the BoletÃn de la Sociedad Geográfica de Lima, Vols. 7 and 8, -1898-1900. They represent the conditions at three observation hours -during the summers (Dec., Jan.) of 1897-1898, 1898-1899, 1899-1900 and -the winters (June, July) of 1898 and 1899." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 84—Cloudiness at Callao. Figures are drawn from -data in the BoletÃn de la Sociedad Geográfica de Lima, Vols. 7 and 8, -1898-1900. They represent the conditions at three observation hours -during the summers (Dec., Jan.) of 1897-1898, 1898-1899, 1899-1900 and -the winters (June, July) of 1898 and 1899.</p> -</div> - -<p>During the southern summer on account of the greater relative difference -between the temperatures of land and water, the sea-breeze attains its -maximum strength. It then accomplishes its greatest work in the desert. -On the pampa of La Joya, for example, the sand dunes move most rapidly -in the summer. According to the Peruvian Meteorological Records of the -Harvard Astronomical Observatory the average movement of the dunes from -April to September, 1900, was 1.4 inches per day, while during the -summer months of the same year it was 2.7 inches. In close agreement are -the figures for the wind force, the record for which also<a name="page_133" id="page_133"></a> shows that 95 -per cent of the winds with strength over 10 miles per hour blew from a -southerly direction. Yet during this season the coast is generally -clearest of fog and cloud. The explanation appears to lie in the -exceedingly delicate nature of the adjustments between the various -rain-making forces. The relative humidity of the air from the sea is -always high, but on the immediate coast is slightly less so in summer -than in winter. Thus in Mollendo the relative humidity during the winter -of 1895 was 81 per cent; during the summer 78 per cent. Moreover, the -temperature of the Coast Range is considerably higher in summer than in -winter, and there is a tendency to reëvaporation of any moisture that -may be blown against it. The immediate shore, indeed, may still be -cloudy as is the case at Callao, which actually has its cloudiest season -in the summer but the hills are comparatively clear. In consequence the -sea-air passes over into the desert, where the relative increase in -temperature has not been so great (compare Mollendo and La Joya in the -curve for mean monthly temperature), with much higher vapor content than -in winter. The relative humidity for the winter season at La Joya, 1895, -was 42.5 per cent; for the summer season 57 per cent. The influence of -the great barrier of the Maritime Cordillera, aided<a name="page_134" id="page_134"></a> doubtless by -convectional rising, causes ascent of the comparatively humid air and -the formation of cloud. Farther eastward, as the topographic influence -is more strongly felt, the cloudiness increases until on the border -zone, about 8,000 feet in elevation, it may thicken to actual rain. Data -have been selected to demonstrate this eastern gradation of -meteorological phenomena.</p> - -<p><a name="fig_85" id="fig_85"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_134a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_134a_sml.jpg" width="203" height="102" alt="Fig. 85—Temperature curves for Mollendo (solid lines) -and La Joya (broken lines) April, 1894, to December, 1895, drawn from -data in Peruvian Meteorology, 1892-1895, Annals of the Astronomical -Observatory of Harvard College, Vol. 49, Pt. 2, Cambridge, Mass., 1908. -The approximation of the two curves of maximum temperature during the -winter months contrasts with the well-maintained difference in minimum -temperatures throughout the year." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 85—Temperature curves for Mollendo (solid lines) -and La Joya (broken lines) April, 1894, to December, 1895, drawn from -data in Peruvian Meteorology, 1892-1895, Annals of the Astronomical -Observatory of Harvard College, Vol. 49, Pt. 2, Cambridge, Mass., 1908. -The approximation of the two curves of maximum temperature during the -winter months contrasts with the well-maintained difference in minimum -temperatures throughout the year.</p> -</div> - -<p><a name="fig_86" id="fig_86"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_134b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_134b_sml.jpg" width="209" height="60" alt="Fig. 86—Mean monthly cloudiness for Mollendo (solid -line) and La Joya (broken line) from April, 1892, to December, 1895. -Mollendo, 80 feet elevation, has the maximum winter cloudiness -characteristic of the seaward slope of the Coast Range (compare Fig. 82 ) -while the desert station of La Joya, 4,140 feet elevation, has typical -summer cloudiness (compare Fig. 83). Figures are drawn from data in -Peruvian Meteorology, 1892-1895, Annals of the Astronomical Observatory -of Harvard College, Vol. 49, Pt. 2, Cambridge, Mass., 1908." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 86—Mean monthly cloudiness for Mollendo (solid -line) and La Joya (broken line) from April, 1892, to December, 1895. -Mollendo, 80 feet elevation, has the maximum winter cloudiness -characteristic of the seaward slope of the Coast Range (compare <a href="#fig_82">Fig. 82</a>) -while the desert station of La Joya, 4,140 feet elevation, has typical -summer cloudiness (compare <a href="#fig_83">Fig. 83</a>). Figures are drawn from data in -Peruvian Meteorology, 1892-1895, Annals of the Astronomical Observatory -of Harvard College, Vol. 49, Pt. 2, Cambridge, Mass., 1908.</p> -</div> - -<p><a name="fig_87" id="fig_87"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_135_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_135_sml.jpg" width="215" height="123" alt="Fig. 87—Wind roses for La Joya for the period April, -1892, to December, 1895. Compare the strong afternoon indraught from the -south with the same phenomenon at Mollendo, Fig. 79. Figures drawn from -data in Peruvian Meteorology, 1892-1895, Annals of the Astronomical -Observatory of Harvard College, Vol. 39, Pt. 2, Cambridge, Mass., 1906." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 87—Wind roses for La Joya for the period April, -1892, to December, 1895. Compare the strong afternoon indraught from the -south with the same phenomenon at Mollendo, <a href="#fig_79">Fig. 79</a>. Figures drawn from -data in Peruvian Meteorology, 1892-1895, Annals of the Astronomical -Observatory of Harvard College, Vol. 39, Pt. 2, Cambridge, Mass., 1906.</p> -</div> - -<p>At La Joya, a station on the desert northeast of Mollendo at an -elevation of 4,140 feet, cloudiness is always slight, but it increases -markedly during the summer. Caraveli, at an altitude of<a name="page_135" id="page_135"></a> 5,635 feet,<a name="FNanchor_22_22" id="FNanchor_22_22"></a><a href="#Footnote_22_22" class="fnanchor">[22]</a> -and near the eastern border of the pampa, exhibits a tendency toward the -climatic characteristics of the adjacent zone. Data for a camp station -out on the pampa a few leagues from the town, were collected by Mr. J. -P. Little of the staff of the Peruvian Expedition of 1912-13. They -relate to the period January to March, 1913. Wind roses for these months -show the characteristic light northwesterly winds of the early morning -hours, in sharp contrast with the strong south and southwesterly -indraught of the afternoon. The daily march of cloudiness is closely -coördinated. Quotations from Mr. Little’s field notes follow:</p> - -<p>“In the morning there is seldom any noticeable wind. A breeze starts at -10 <span class="smcap">A. M.</span>, generally about 180° (i. e. due south), increases to 2 or 3 -velocity at noon, having veered some 25° to the southwest. It reaches a -maximum velocity of 3 to 4 at about 4.00 <span class="smcap">P. M.</span>, now coming about 225° -(i. e. southwest). By 6 <span class="smcap">P. M.</span> the wind<a name="page_136" id="page_136"></a> has died down considerably and -the evenings are entirely free from it. The wind action is about the -same every day. It is not a cold wind and, except with the fog, not a -damp one, for I have not worn a coat in it for three weeks. It has a -free unobstructed sweep across fairly level pampas.... At an interval of -every three or four days a dense fog sweeps up from the southwest, dense -enough for one to be easily lost in it. It seldom makes even a sprinkle -of rain, but carries heavy moisture and will wet a man on horseback in -10 minutes. It starts about 3 <span class="smcap">P.M.</span> and clears away by 8.00 <span class="smcap">P. M.</span>.... -During January, rain fell in camp twice on successive days, starting at -3.00 <span class="smcap">P. M.</span> and ceasing at 8.00 <span class="smcap">P. M.</span> It was merely a light, steady rain, -more the outcome of a dense fog than a rain-cloud of quick approach. In -Caraveli, itself, I am told that it rains off and on all during the -month in short, light showers.†This record is dated early in February -and, in later notes, that month and March are recorded rainless.</p> - -<p><a name="fig_88" id="fig_88"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_136_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_136_sml.jpg" width="213" height="131" alt="Fig. 88—Wind roses for a station on the eastern border -of the Coast Desert near Caraveli during the summer (January to March) -of 1913. Compare with Fig. 87. The diameter of the circle in each case -represents the proportion of calm. Note the characteristic morning -calm." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 88—Wind roses for a station on the eastern border -of the Coast Desert near Caraveli during the summer (January to March) -of 1913. Compare with <a href="#fig_87">Fig. 87</a>. The diameter of the circle in each case -represents the proportion of calm. Note the characteristic morning -calm.</p> -</div> - -<p>Chosica (elevation 6,600 feet), one of the meteorological stations of -the Harvard Astronomical Observatory, is still nearer the<a name="page_137" id="page_137"></a> border. It -also lies farther north, approximately in the latitude of Lima, and this -in part may help to explain the greater cloudiness and rainfall. The -rainfall for the year 1889-1890 was 6.14 inches, of which 3.94 fell in -February. During the winter months when the principal wind observations -were taken, over 90 per cent showed noon winds from a southerly -direction while in the early morning northerly winds were frequent. It -is also noteworthy that the “directions of the upper currents of the -atmosphere as recorded by the motion of the clouds was generally between -N. and E.†Plainly we are in the border region where climatic influences -are carried over from the plateau and combine their effects with those -from Pacific sources. Arequipa, farther south, and at an altitude of -7,550 feet, resembles Chosica. For the years 1892 to 1895 its mean -rainfall was 5.4 inches.</p> - -<p><a name="fig_89" id="fig_89"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_137_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_137_sml.jpg" width="209" height="98" alt="Fig. 89—Cloudiness at the desert station of Fig. 88 -(near Caraveli), for the summer (January to March) of 1913." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 89—Cloudiness at the desert station of <a href="#fig_88">Fig. 88</a> -(near Caraveli), for the summer (January to March) of 1913.</p> -</div> - -<p>Besides the seasonal variations of precipitation there are longer -periodic variations that are of critical importance on the Coast Range. -At times of rather regular recurrence, rains that are heavy and general -fall there. Every six or eight years is said to be a period of rain, but -the rains are also said to occur sometimes at intervals of four years or -ten years. The regularity is only approximate. The years of heaviest -rain are commonly associated with an unusual frequency of winds from the -north, and an abnormal development of the warm current, El Niño, from -the<a name="page_138" id="page_138"></a> Gulf of Guayaquil. Such was the case in the phenomenally rainy year -of 1891. The connection is obscure, but undoubtedly exists.</p> - -<p>The effects of the heavy rains are amazing and appear the more so -because of the extreme aridity of the country east of them. During the -winter the desert traveler finds the air temperature rising to -uncomfortable levels. Vegetation of any sort may be completely lacking. -As he approaches the leeward slope of the Coast Range, a cloud mantle -full of refreshing promise may be seen just peeping over the crest (Fig. -91). Long, slender cloud filaments project eastward over the margin of -the desert. They are traveling rapidly but they never advance far over -the hot wastes, for their eastern margins are constantly undergoing -evaporation. At times the top of the cloud bank rises well above the -crest of the Coast Range, and it seems to the man from the temperate -zone as if a great thunderstorm were rising in the west. But for all -their menace of wind and rain the clouds never get beyond the desert -outposts. In the summer season the aspect changes, the heavy yellow sky -of the desert displaces the murk of the coastal mountains and the -bordering sea.</p> - -<p><a name="fig_90" id="fig_90"></a></p> - -<div class="figleft" style="width: 116px;"> -<a href="images/ill_page_138_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_138_sml.jpg" width="116" height="87" alt="Fig. 90—Cloudiness at Chosica, July, 1889, to September, -1890. Chosica, a station on the Oroya railroad east of Lima, is situated -on the border region between the desert zone of the coast and the -mountain zone of yearly rains. The minimum cloudiness recorded about 11 -a. m. is shown by a broken line; the maximum cloudiness, about 7 p. m., -by a dotted line, and the mean for the 24 hours by a heavy solid line. -The curves are drawn from data in Peruvian Meteorology, 1889-1890, -Annals of the Astronomical Observatory of Harvard College, Vol. 39, Pt. -1, Cambridge, Mass., 1899." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 90—Cloudiness at Chosica, July, 1889, to September, -1890. Chosica, a station on the Oroya railroad east of Lima, is situated -on the border region between the desert zone of the coast and the -mountain zone of yearly rains. The minimum cloudiness recorded about 11 -a. m. is shown by a broken line; the maximum cloudiness, about 7 p. m., -by a dotted line, and the mean for the 24 hours by a heavy solid line. -The curves are drawn from data in Peruvian Meteorology, 1889-1890, -Annals of the Astronomical Observatory of Harvard College, Vol. 39, Pt. -1, Cambridge, Mass., 1899.</p> -</div> - -<p>It is an age-old strife renewed every year and limited to a narrow field -of action, wonderfully easy to observe. We saw it in its most striking -form at the end of the winter season in October, 1911, and for more than -a day watched the dark clouds rise ominously only to melt into nothing -where the desert holds sway. At night we camped beside a scum-coated -pool of alkali water no<a name="page_139" id="page_139"></a> larger than a wash basin. It lay in a valley -that headed in the Coast Range, and carried down into the desert a mere -trickle that seeped through the gravels of the valley floor. A little -below the pool the valley cuts through a mass of granite and becomes a -steep-walled gorge. The bottom is clogged with waste, here boulders, -there masses of both coarse and fine alluvium. The water in the valley -was quite incapable of accomplishing any work except that associated -with solution and seepage, and we saw it in the wet season of an -unusually wet year. Clearly there has been a diminution in the water -supply. But time prevented us from exploring this particular valley to -its head, to see if the reduction were due to a change of climate, or -only to capture of the head-waters by the vigorous rain-fed streams that -enjoy a favorable position on the wet seaward slopes and that are -extending their watershed aggressively toward the east at the expense of -their feeble competitors in the dry belt.</p> - -<p>An early morning start enabled me to witness the whole series of changes -between the clear night and the murky day, and to pass in twelve hours -from the dry desert belt through the wet belt, and emerge again into the -sunlit terraces at the western foot of the Coast Range. Two hours before -daylight a fog descended from the hills and the going seemed to be -curiously heavy for the beasts. At daybreak my astonishment was great to -find that it was due to the distinctly moist sand. We were still in the -desert. There was not a sign of a bush or a blade of grass. Still, the -surface layer, from a half inch to an inch thick, was really wet. The -fog that overhung the trail lifted just before sunrise, and at the first -touch of the sun melted away as swiftly as it had come. With it went the -surface moisture and an hour after sunrise the dust was once more rising -in clouds around us.</p> - -<p>We had no more than broken camp that morning when a merchant with a -pack-train passed us, and shouted above the bells of the leading animals -that we ought to hurry or we should get caught in the rain at the pass. -My guide, who, like many of his kind, had never before been over the -route he pretended to know, asked him in heaven’s name what drink in -distant Camaná<a name="page_140" id="page_140"></a> whence he had come produced such astonishing effects as -to make a man talk about rain in a parched desert. We all fell to -laughing and at our banter the stranger stopped his pack-train and -earnestly urged us to hurry, for, he said, the rains beyond the pass -were exceptionally heavy this year. We rode on in a doubtful state of -mind. I had heard about the rains, but I could not believe that they -fell in real showers!</p> - -<p>About noon the cloud bank darkened and overhung the border of the -desert. Still the sky above us was clear. Then happened what I can yet -scarcely believe. We rode into the head of a tiny valley that had cut -right across the coast chain. A wisp of cloud, an outlier of the main -bank, lay directly ahead of us. There were grass and bushes not a -half-mile below the bare dry spot on which we stood. We were riding down -toward them when of a sudden the wind freshened and the cloud wisp -enveloped us, shutting out the view, and ten minutes later the moisture -had gathered in little beads on the manes of our beasts and the trail -became slippery. In a half-hour it was raining and in an hour we were in -the midst of a heavy downpour. We stopped and pastured our famished -beasts in luxuriant clover. While they gorged themselves a herd of -cattle drifted along, and a startled band of burros that suddenly -confronted our beasts scampered out of sight in the heavy mist. Later we -passed a herdsman’s hut and long before we reached him he shouted to us -to alter our course, for just ahead the old trail was wet and -treacherous at this time of year. The warning came too late. Several of -our beasts lost their footing and half rolled, half slid, down hill. One -turned completely over, pack and all, and lay in the soft mud calmly -taking advantage of the delay to pluck a few additional mouthfuls of -grass. We were glad to reach firmer ground on the other side of the -valley.</p> - -<p>The herdsmen were a hospitable lot. They had come from Camaná and rarely -saw travelers. Their single-roomed hut was mired so deeply that one -found it hard to decide whether to take shelter from the rain inside or -escape the mud by standing in the rain outside. They made a little -so-called cheese, rounded up and<a name="page_141" id="page_141"></a> counted the cattle on clear days, -drove them to the springs from time to time, and talked incessantly of -the wretched rains in the hills and the delights of dry Camaná down on -the coast. We could not believe that only some hours’ traveling -separated two localities so wholly unlike.</p> - -<p>The heavy showers and luxuriant pastures of the wet years and the light -local rains of the dry years endow the Coast Range with many peculiar -geographic qualities. The heavy rains provide the desert people at the -foot of the mountains such a wealth of pasture for their burdensome -stock as many oases dwellers possess only in their dreams. From near and -far cattle are driven to the wet hill meadows. Some are even brought in -from distant valleys by sea, yet only a very small part of the rich -pastures can be used. It is safe to say that they could comfortably -support ten times the number of cattle, mules, and burros that actually -graze upon them. The grass would be cut for export if the weather were -not so continually wet and if there were not so great a mixture of -weeds, flowers, and shrubs.</p> - -<p>Then come the dry years. The surplus stock is sold, and what remains is -always maintained at great expense. In 1907 I saw stock grazing in a -small patch of dried vegetation back of Mollendo, although they had to -be driven several miles to water. They looked as if they were surviving -with the greatest difficulty and their restless search for pasture was -like the search of a desperate hunter of game. In 1911 the same tract -was quite devoid of grass, and except for the contour-like trails that -completely covered the hills no one would even guess that this had -formerly been a cattle range. The same year, but five months later, a -carpet of grass, bathed in heavy mist, covered the soil; a trickle of -water had collected in pools on the valley floor; several happy families -from the town had laid out a prosperous-looking garden; there were -romping children who showed me where to pick up the trail to the port; -on every hand was life and activity because the rains had returned -bringing plenty in their train. I asked a native how often he was -prosperous.</p> - -<p>“Segun el temporal y la Providencia†(according to the<a name="page_142" id="page_142"></a> weather and to -Providence), he replied, as he pointed significantly to the pretty green -hills crowned with gray mist.</p> - -<p>It, therefore, seems fortunate that the Coast Range is so placed as to -intercept and concentrate a part of the moisture that the sea-winds -carry, and doubly fortunate that its location is but a few miles from -the coast, thereby giving temporary relief to the relatively crowded -people of the lower irrigated valleys and the towns. The wet years -formerly developed a crop of prospectors. Pack animals are cheaper when -there is good pasture and they are also easier to maintain. So when the -rains came the hopeful pick-and-shovel amateurs began to emigrate from -the towns to search for ore among the discolored bands of rock intruded -into the granite masses of the coastal hills. However, the most likely -spots have been so thoroughly and so unsuccessfully prospected for many -years that there is no longer any interest in the “mines.â€</p> - -<p>Transportation rates are still most intimately related to the rains. My -guide had two prices—a high price if I proposed to enter a town at -night and thus require him to buy expensive forage; a low price if I -camped in the hills and reached the town in time for him to return to -the hills with his animals. Inquiry showed that this was the regular -custom. I also learned that in packing goods from one part of the coast -to another forage must be carried in dry years or the beasts required to -do without. In wet years by a very slight detour the packer has his -beasts in good pasture that is free for all. The merchant who dispatches -the goods may find his charges nearly doubled in extremely dry years. -Goods are more expensive and there is a decreased consumption. The -effects of the rains are thus transmitted from one to another, until at -last nearly all the members of a community are bearing a share of the -burdens imposed by drought. As always there are a few who prosper in -spite of the ill wind. If the pastures fail, live stock <i>must</i> be sold -and the dealers ship south to the nitrate ports or north to the large -coast towns of Peru, where there is always a demand. Their business is -most active when it is dry or rather at the beginning, of the dry -period. Also if transport by land routes becomes too expensive the small -traders<a name="page_143" id="page_143"></a> turn to the sea routes and the carriers have an increased -business. But so far as I have been able to learn, dry years favor only -a few scattered individuals.</p> - -<p>To the traveler on the west coast it is a source of constant surprise -that the sky is so often overcast and the ports hidden by fog, while on -every hand there are clear evidences of extreme aridity. Likewise it is -often inquired why the sunsets there should be often so superlatively -beautiful during the winter months when the coast is fog bound. Why a -desert when the air is so humid? Why striking sunsets when so many of -the days are marked by dull skies? As we have seen in the first part of -this chapter, the big desert tracts lie east of the Coast Range, and -there, excepting slight summer cloudiness, cloudless skies are the rule. -The desert just back of the coast is in many parts of Peru only a narrow -fringe of dry marine terraces quite unlike the real desert in type of -weather and in resources. The fog bank overhanging it forms over the -Humboldt Current which lies off shore; it drifts landward with the -onshore wind; it forms over the upwelling cold water between the current -and the shore; it gathers on the seaward slopes of the coastal hills as -the inflowing air ascends them in its journey eastward. Sometimes it -lies on the surface of the land and the water; more frequently it is -some distance above them. On many parts of the coast its characteristic -position is from 2,000 to 4,000 feet above sea level, descending at -night nearly or quite to the surface, ascending by day and sometimes all -but disappearing except as rain-clouds on the hills.<a name="FNanchor_23_23" id="FNanchor_23_23"></a><a href="#Footnote_23_23" class="fnanchor">[23]</a> Upon the local -behavior of the fog bank depends in large measure the local climate. A -general description of the coastal climate will have many<a name="page_144" id="page_144"></a> exceptions. -The physical principles involved are, however, the same everywhere. I -take for discussion therefore the case illustrated by <a href="#fig_92">92</a> , since -this also displays with reasonable fidelity the conditions along that -part of the Peruvian coast between Camaná and Mollendo which lies in the -field of work of the Yale Peruvian Expedition of 1911.</p> - -<p>Three typical positions of the fog bank are shown in the figure, and a -fourth—that in which the bank extends indefinitely westward—may be -supplied by the imagination.</p> - -<p>If the cloud bank be limited to <i>C</i> only the early morning hours at the -port are cloudy. If it extend to <i>B</i> the sun is obscured until midday. -If it reach as far west as <i>A</i> only a few late afternoon hours are -sunny. Once in a while there is a sudden splash of rain—a few drops -which astonish the traveler who looks out upon a parched landscape. The -smaller drops are evaporated before reaching the earth. In spite of the -ever-present threat of rain the coast is extremely arid. Though the -vegetation appears to be dried and burned up, the air is humid and for -months the sky may be overcast most of the time. So nicely are the -rain-making conditions balanced that if one of our ordinary low-pressure -areas, or so-called cyclonic storms, from the temperate zone were set in -motion along the foot of the mountains, the resulting deluge would -immediately lay the coast in ruins. The cane-thatched, mud-walled huts -and houses would crumble in the heavy rain like a child’s sand pile -before a rising sea; the alluvial valley land would be coated with -infertile gravel; and mighty rivers of sand, now delicately poised on -arid slopes, would inundate large tracts of fertile soil.</p> - -<p><a name="fig_91" id="fig_91"></a></p> - -<p><a name="fig_92" id="fig_92"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_144a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_144a_sml.jpg" width="215" height="253" alt="Fig. 91—Looking down the canyon of the Majes River to -the edge of the cloud bank formed against the Coast Range back of -Camaná." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 91—Looking down the canyon of the Majes River to -the edge of the cloud bank formed against the Coast Range back of -Camaná.</p> - -<p class="caption"><span class="smcap">Fig. 92</span>—Topographic and climatic cross-section to show -the varying positions of the cloud bank on the coast of Peru, the dry -terrace region, and the types of stream profiles in the various belts.</p> -</div> - -<p>If the fog and cloud bank extend westward indefinitely, the entire day -may be overcast or the sun appear for a few moments only through -occasional rifts. Generally, also, it will make an appearance just -before sunset, its red disk completely filling the narrow space between -the under surface of the clouds and the water. I have repeatedly seen -the ship’s passengers and even the crew leave the dinner table and -collect in wondering groups about the port-holes and doorways the better -to see the marvelous play of<a name="page_145" id="page_145"></a> colors between sky and sea. It is -impossible not to be profoundly moved by so majestic a scene. A long -resplendent path of light upon the water is reflected in the clouds. -Each cloud margin is tinged with red and, as the sun sinks, the long -parallel bands of light are shortened westward, changing in color as -they go, until at last the full glory of the sunset is concentrated in a -blazing arc of reds, yellows, and purples, that to most people quite -atones for the dull gray day and its humid air.</p> - -<p>At times the clouds are broken up by the winds and scattered -helter-skelter through the west. A few of them may stray into the path -of the sun temporarily to hide it and to reflect its primary colors when -the sun reappears. From the main cloud masses there reach out slender -wind-blown streamers, each one delicately lighted as the sun’s rays -filter through its minute water particles. Many streamers are visible -for only a short distance, but when the sun catches them their filmy -invisible fingers become delicate bands of light, some of which rapidly -grow out almost to the dome of the sky. Slowly they retreat and again -disappear as the rays of the sun are gradually shut off by the upturning -curve of the earth.</p> - -<p>The unequal distribution of precipitation in the climatic zones of -western Peru has important hydrographic consequences. These will now be -considered. In the preceding figure four types of stream profiles are -displayed and each has its particular relation to the cloud bank. Stream -1 is formed wholly upon the coastal terraces beneath the cloud bank. It -came into existence only after the uplift of the earth’s crust that -brought the wave-cut platforms above sea level. It is extremely youthful -and on account first of the small seepage at its headquarters—it is -elsewhere wholly without a tributary water supply—and, second, of the -resistant granite that occurs along this part of the coast, it has very -steep and irregular walls and an ungraded floor. Many of these -“quebradas†are difficult to cross. A few of them have fences built -across their floors to prevent the escape of cattle and burros that -wander down from the grassy hills into the desert zone. Others are -partitioned off into corrals by stone fences, the steep<a name="page_146" id="page_146"></a> walls of the -gorge preventing the escape of the cattle. To these are driven the -market cattle, or mules and burros that are required for relays along -the shore trail.</p> - -<p>Stream 2 heads in the belt of rains. Furthermore it is a much older -stream than 1, since it dates back to the time when the Coast Range was -first formed. It has ample tributary slopes and a large number of small -valleys. A trickle of water flows down to become lost in the alluvium of -the lower part of the valley or to reappear in scattered springs. Where -springs and seepage occur together, an olive grove or a garden marks the -spot, a corral or two and a mud or stone or reed hut is near by, and -there is a tiny oasis. Some of these dots of verdure become so dry -during a prolonged drought that the people, long-established, move away. -To others the people return periodically. Still others support permanent -settlements.</p> - -<p>Stream 3 has still greater age. Its only competitors are the feeble, -almost negligible, streams that at long intervals flow east toward the -dry zone. Hence it has cut back until it now heads in the desert. Its -widely branched tributaries gather moisture from large tracts. There is -running water in the valley floor even down in the terrace zone. At -least there are many dependable springs and the permanent homes that -they always encourage. A valley of this type is always marked by a -well-defined trail that leads from settlement to settlement and eastward -over the “pass†to the desert and the Andean towns.</p> - -<p>Stream 4 is a so-called “antecedent†stream. It existed before the Coast -Range was uplifted and cut its channel downward as the mountains rose in -its path. The stretch where it crosses the mountains may be a canyon -with a narrow, rocky, and uncultivable floor, so that the valley trails -rise to a pass like that at the head of stream 3, and descend again to -the settlements at the mouth of 4. There is in this last type an -abundance of water, for the sources of the stream are in the zone of -permanent snows and frequent winter rains of the lofty Cordillera of the -Andes. The settlements along this stream are continuous, except where -shut-ins occur—narrow, rocky defiles caused by more resistant rock<a name="page_147" id="page_147"></a> -masses in the path of the stream. Here and there are villages. The -streams have fish. When the water rises the river may be unfordable and -people on opposite sides must resort to boats or rafts.<a name="FNanchor_24_24" id="FNanchor_24_24"></a><a href="#Footnote_24_24" class="fnanchor">[24]</a></p> - -<h4>EASTERN BORDER CLIMATES</h4> - -<p>On windward mountain slopes there is always a belt of maximum -precipitation whose elevation and width vary with the strength of the -wind, with the temperature, and with the topography. A strong and -constant wind will produce a much more marked concentration of the -rainfall. The belt is at a low elevation in high latitudes and at a high -elevation in low latitudes, with many irregularities of position -dependent upon the local and especially the minimum winter temperature. -The topographic controls are important, since the rain-compelling -elevation may scatter widely the localities of maximum precipitation or -concentrate them within extremely narrow limits. The human effects of -these climatic conditions are manifold. Wherever the heaviest rains are, -there, too, as a rule, are the densest forests and often the most -valuable kinds of trees. If the general climate be favorable and the -region lie near dense and advanced populations, exploitation of the -forest and progress of the people will go hand in hand. If the region be -remote and some or all of the people in a primitive state, the forest -may hinder communication and retard development, especially if it lie in -a hot zone where the natural growth of population is slow.... These are -some of the considerations we shall keep in mind while investigating the -climate of the eastern border of the Peruvian Andes.</p> - -<p><a name="fig_93" id="fig_93"></a></p> -<p><a name="fig_93b" id="fig_93b"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_148a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_148a_sml.jpg" width="211" height="64" alt="Fig. 93A—Cloud types and rainfall belts on the eastern -border of the Peruvian Andes in the dry season, southern winter. The -zone of maximum rainfall extends approximately from 4,000 to 10,000 feet -elevation." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 93A—Cloud types and rainfall belts on the eastern -border of the Peruvian Andes in the dry season, southern winter. The -zone of maximum rainfall extends approximately from 4,000 to 10,000 feet -elevation.</p> -</div> - -<div class="figcenter"> -<a href="images/ill_page_148b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_148b_sml.jpg" width="212" height="62" alt="Fig. 93B—Cloud types and rainfall belts on the eastern -border of the Peruvian Andes in the wet season, southern summer." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 93B—Cloud types and rainfall belts on the eastern -border of the Peruvian Andes in the wet season, southern summer.</p> -</div> - -<p>The belt of maximum precipitation on the eastern border of the Andean -Cordillera in Peru lies between 4,000 and 10,000 feet. Judging by the -temporary records of the expedition and especially<a name="page_148" id="page_148"></a> by the types of -forest growth, the heaviest rains occur around 8,000 feet. It is between -these elevations that the densest part of the Peruvian <i>montaña</i> -(forest) is found. The cold timber line is at 10,500 feet with -exceptional extensions of a few species to 12,500 feet. In basins or -deep secluded valleys near the mountain border, a dry timber line occurs -at 3,000 feet with many variations in elevation due to the variable -declivity and exposure of the slopes and degree of seclusion of the -valleys. Elsewhere, the mountain forest passes without a break into the -plains forest with change in type but with little change in density. The -procumbent and suppressed trees of the cold timber line in regions of -heavy winter snows are here absent, for the snows rarely reach below -14,000 feet and even at that elevation they are only light and -temporary. The line of perpetual snow is at 15,000 feet. This permanent -gap of several thousand feet vertical elevation between the zone of snow -and the zone of forest permits the full extension of many pioneer forest -species, which is to say, there is an irregular<a name="page_149" id="page_149"></a> development of the cold -timber line. It also permits the full use of the pasture belt above the -timber (<a href="#fig_97">Fig. 97</a>), hence permanent habitations exist but little below the -snowline and a group of distinctive high-mountain folk enjoys a wide -distribution. There is a seasonal migration here, but it is not -wholesale; there are pastures snow-covered in the southern winter, but, -instead of the complete winter burial of the Alpine meadows of our -western mountains, we have here only a buried upper fringe. All the rest -of the pasture belt is open for stock the year round.</p> - -<p>This climatic distinction between the lofty grazing lands of the tropics -and those of the temperate zones is far-reaching. Our mountain forests -are not utilized from above but from below. Furthermore, the chief ways -of communication lead around our forests, or, if through them, only for -the purpose of putting one population group in closer touch with -another. In the Peruvian Andes the largest population groups live above -the forest, not below it or within it. It must be and is exploited from -above.</p> - -<p>Hence railways to the eastern valleys of Peru have two chief objects, -(1) to get the plantation product to the dense populations above the -forest and (2) to bring timber from the <i>montaña</i> to the treeless -plateau. The mountain prospector is always near a habitation; the rubber -prospector goes down into the forested valleys and plains far from -habitations. The forest separates the navigable streams from the chief -towns of the plateau; it does not lead down to rich and densely -populated valley floors.</p> - -<p>Students in eastern Peru should find it a little difficult to understand -poetical allusions to silent and lonely highlands in contrast to the -busy life of the valleys. To them Shelley’s description of the view from -the Euganean Hills of northern Italy,</p> - -<div class="poem"><div class="stanza"> -<span class="i0">“Beneath is spread like a green sea<br /></span> -<span class="i1">The waveless plain of Lombardy, ...<br /></span> -<span class="i1">Islanded by cities fair,â€<br /></span> -</div></div> - -<p class="nind">might well seem to refer to a world that is upside down.</p> - -<p>There is much variation in the forest types between the mountains and -the plains. At the top of the forest zone the warm<a name="page_150" id="page_150"></a> sunny slopes have a -forest cover; the shady slopes are treeless. At the lower edge of the -grassland, only the shady slopes are forested (Fig. 53B). Cacti of -arboreal size and form grow on the lofty mountains far above the limits -of the true forest; they also appear at 3,000 feet in modified form, -large, rank, soft-spined, and in dense stands on the semi-arid valley -floors below the dry timber line. Large tracts between 8,000 and 10,000 -feet are covered with a forest growth distributed by species—here a -dense stand of one type of tree, there another. This is the most -accessible part of the Peruvian forest and along the larger valleys it -is utilized to some extent. The number of species is more limited, -however, and the best timber trees are lower down. Though often referred -to as jungle, the lowlier growths at the upper edge of the forest zone -have no resemblance to the true jungle that crowds the lowland forest. -They are merely an undergrowth, generally open, though in some places -dense. They are nowhere more dense than many examples from New England -or the West.</p> - -<p>Where deep valleys occur near the border of the mountains there is a -semi-arid climate below and a wet climate above, with a correspondingly -greater number of species within short distances of each other. This is -a far more varied forest than at the upper edge of the timber zone or -down on the monotonous plains. It has a higher intrinsic value than any -other. That part of it between the Pongo and Yavero (1,200 to 4,000 -feet) is very beautiful, with little undergrowth except a light -ground-cover of ferns. The trees are from 40 to 100 feet in height with -an average diameter of about 15 inches. It would yield from 3,000 to -5,000 board feet per acre exclusive of the palms. There are very few -vines suspended from the forest crown and the trunks run clear from 30 -to 60 feet above the ground. Were there plenty of labor and a good -transportation line, these stands would have high economic value. Among -the most noteworthy trees are the soft white cedar, strong and light; -the amarillo and the sumbayllo, very durable in water; the black nogal, -and the black balsam, straight and easy to work; the heavy yunquero, -which turns pink when dry; the chunta or black palm, so hard and -straight and easy to split<a name="page_151" id="page_151"></a> that wooden nails are made from it; and the -rarer sandy matico, highly prized for dug-out canoes. Also from the -chunta palm, hollow except for a few central fibers, easily removed, -pipes are made to convey water. The cocobolo has a rich brown color and -a glossy surface and is very rare, hence is much sought after for use in -furniture making. Most of these woods take a brilliant polish and -exhibit a richness and depth of color and a beauty of grain that are -rare among our northern woods.</p> - -<p><a name="fig_94" id="fig_94"></a></p> - -<p><a name="fig_95" id="fig_95"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_150a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_150a_sml.jpg" width="212" height="321" alt="Fig. 94—Cloud belt at 11,000 feet in the Apurimac Canyon -near Incahuasi. For a regional diagram and a climatic cross-section see -Figs. 32 and 33." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 94—Cloud belt at 11,000 feet in the Apurimac Canyon -near Incahuasi. For a regional diagram and a climatic cross-section see -Figs. <a href="#fig_32">32</a> and <a href="#fig_33">33</a>.</p> - -<p class="caption"><span class="smcap">Fig. 95</span>—The tropical forest near Pabellon on the slopes -of the Urubamba Valley. Elevation 3,000 feet (915 m.).</p> -</div> - -<p>The plains forest northeast of the mountains is in the zone of moderate -rainfall where there is one long dry season and one long wet season. -When it is dry the daytime temperatures rise rapidly to such high levels -that the relative humidity of the air falls below 50 per cent (Fig. -110). The effect on the vegetation is so marked that many plants pass -into a distinctly wilted condition. On clear days the rapid fall in the -relative humidity is astonishing. By contrast the air on the mountain -border heats more slowly and has a higher relative humidity, because -clouds form almost constantly in the ascending air currents and reflect -and absorb a large part of the heat of the sun’s rays. It is striking to -find large tracts of cane and bamboo on the sand bars and on wet shady -hillslopes in the slope belt, and to pass out of them in going to the -plains with which we generally associate a swamp vegetation. They exist -on the plains, but only in favored, that is to say wet, spots. Larger -and more typical tracts grow farther north where the heavier rains of -the Amazon basin fall.</p> - -<p>The floods of the wet tropical season also have a restricting influence -upon the tropical forest. They deliver such vast quantities of water to -the low-gradient lowland streams that the plains rivers double, even -treble, their width and huge pools and even temporary lakes form in the -shallow depressions back of the natural levees. Of trees in the flooded -areas there are only those few species that can grow standing in water -several months each year. There are also cane and bamboo, ferns in -unlimited numbers, and a dense growth of jungle. These are the haunts of -the peccary, the red forest deer, and the jungle cat. Except along the -narrow and tortuous animal trails the country is quite impassable.<a name="page_152" id="page_152"></a> Thus -for the sturdiest and most useful forest growth the one-wet-one-dry -season zone of the plains has alternately too much and too little water. -The rubber tree is most tolerant toward these conditions. Some of the -best stands of rubber trees in Amazonia are in the southwestern part of -the basin of eastern Peru and Bolivia, where there is the most typical -development of the habitat marked by the seasonal alternation of floods -and high temperatures.</p> - -<p>When tropical agriculture is extended to the plains the long dry season -will be found greatly to favor it. The southwestern quadrant of the -Amazon basin, above referred to, is the best agricultural area within -it. The northern limits of the tract are only a little beyond the Pongo. -Thence northward the climate becomes wetter. Indeed the best tracts of -all extend from Bolivia only a little way into southeastern Peru, and -are coincident with the patchy grasslands that are there interspersed -with belts of woodland and forest. Sugar-cane is favored by a climate -that permits rapid growth with a heavy rainfall and a dry season is -required for quality and for the harvest. Rice and a multitude of -vegetable crops are also well suited to this type of climate. Even corn -can be grown in large quantities.</p> - -<p>At the present time tropical agriculture is almost wholly confined to -the mountain valleys. The reasons are not wholly climatic, as the above -enumeration of the advantages of the plains suggests. The consuming -centers are on the plateau toward the west and limitation to mule pack -transport always makes distance in a rough country a very serious -problem. The valleys combine with the advantage of a short haul a -climate astonishingly like the one just described. In fact it is even -more extreme in its seasonal contrasts. The explanation is dependent -upon precisely the same principles we have hitherto employed. The front -range of the Andes and the course of the Urubamba run parallel for some -distance. Further, the front range is in many places somewhat higher -than the mountain spurs and knobs directly behind it. Even when these -relations are reversed the front range still acts as a barrier to the -rains for all the deep valleys behind it whose<a name="page_153" id="page_153"></a> courses are not directly -toward the plains. Thus, one of the largest valleys in Peru, the -Urubamba, drops to 3,400 feet at Santa Ana and to 2,000 feet at -Rosalina, well within the eastern scarp of the Andes. The mountains -immediately about it are from 6,000 to 10,000 feet high. The result is a -deep semi-arid pocket with only a patchy forest (Fig. 54, p. <a href="#page_079">79</a>).<a name="FNanchor_25_25" id="FNanchor_25_25"></a><a href="#Footnote_25_25" class="fnanchor">[25]</a> In -places the degree of seclusion from the wind is so great that the scrub, -cacti, and irrigation remind one strongly of the desert on the border of -an oasis, only here the transition is toward forests instead of barren -wastes. The dense forest, or <i>montaña</i>, grows in the zone of clouds and -maximum precipitation between 4,000 and 10,000 feet. At the lower limit -it descends a thousand feet farther on shady slopes than it does on -sunny slopes. The continuous forest is so closely restricted to the -cloud belt that in <a href="#fig_99">99</a> the two limits may be seen in one photograph. -All these sharply defined limits and contrasts are due to the fact that -the broad valley, discharging through a narrow and remote gorge, is -really to leeward of all the mountains around it. It is like a real -desert basin except in a lesser degree of exclusion from the rains. If -it were narrow and small the rains formed on the surrounding heights -would be carried over into it. Rain on the hills and sunshine in the -valley is actually the day-by-day weather of the dry season. In the wet -season the sky is overcast, the rains are general, though lighter in the -valley pocket, and plants there have then their season of most rapid -growth. The dry season brings plants to maturity and is the time of -harvest. Hence sugar and cacao plantations on a large scale, hence a -varied life in a restricted area, hence a distinct geographic province -unique in South America.</p> - -<h4>INTER-ANDEAN VALLEY CLIMATES</h4> - -<p>Not all the deep Andean valleys lie on or near the eastern border. Some, -like the Apurimac and the Marañon, extend well<a name="page_154" id="page_154"></a> into the interior of the -Cordillera. Besides these deep remote valleys with their distinct -climatic belts are basins, most of them with outlets to the sea—broad -structural depressions occurring in some cases along large and in others -along small drainage lines. The Cuzco basin at 11,000 feet and the -Abancay basin at 6,000 to 8,000 feet are typical. Both have abrupt -borders, narrow outlets, large bordering alluvial fans, and fertile -irrigable soil. Their difference of elevation occurs at a critical -level. Corn will ripen in the Cuzco basin, but cane will not. Barley, -wheat, and potatoes are the staple crops in the one; sugar-cane, -alfalfa, and fruit in the other. Since both are bordered by high -pastures and by mineralized rocks, the deeper Abancay basin is more -varied. If it were not so difficult to get its products to market by -reason of its inaccessibility, the Abancay basin would be the more -important. In both areas there is less rainfall on the basin floor than -on the surrounding hills and mountains, and irrigation is practised, but -the deeper drier basin is the more dependent upon it. Many small high -basins are only within the limits of potato cultivation. They also -receive proportionately more rain. Hence irrigation is unnecessary. -According as the various basins take in one or another of the different -product levels (<a href="#fig_35">Fig. 35</a>) their life is meager and unimportant or rich -and interesting.</p> - -<p>The deep-valley type of climate has the basin factors more strongly -developed. Below the Canyon of Choqquequirau, a topographic feature -comparable with the Canyon of Torontoy, the Apurimac descends to 3,000 -feet, broadens to several miles, and has large alluvial fans built into -it. Its floor is really arid, with naked gravel and rock, cacti stands, -and gnarled shrubs as the chief elements of the landscape. Moreover the -lower part of the valley is the steeper. A former erosion level is -indicated in <a href="#fig_125">125</a> . When it was in existence the slopes were more -moderate than now and the valley broad and open. Thereupon came uplift -and the incision of the stream to its present level. As a result, a -steep canyon was cut in the floor of a mature valley. Hence the slopes -are in a relation unlike that of most of the slopes in our most familiar -landscapes. The gentle slopes are above, the steep below.<a name="page_155" id="page_155"></a> The break -between the two, a topographic unconformity, may be distinctly traced.</p> - -<p><a name="fig_96" id="fig_96"></a></p> - -<p><a name="fig_97" id="fig_97"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_154a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_154a_sml.jpg" width="316" height="209" alt="Fig. 96—Snow-capped mountain, Soiroccocha, north of -Arma, Cordillera Vilcapampa. The blue glacier ice descends almost to the -edge of a belt of extraordinary woodland growing just under the -snowline. The glacier is seen to overhang the valley and to have built -on the steep valley wall terminal moraines whose outer slopes are almost -precipitous." /></a> -<br /> - -<table border="0" cellpadding="5" cellspacing="0" summary=""> -<tr valign="top"><td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 96—Snow-capped mountain, Soiroccocha, north of -Arma, Cordillera Vilcapampa. The blue glacier ice descends almost to the -edge of a belt of extraordinary woodland growing just under the -snowline. The glacier is seen to overhang the valley and to have built -on the steep valley wall terminal moraines whose outer slopes are almost -precipitous.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig. 97</span>—Shrubby vegetation mixed with grass at 14,000 -feet (4,270 m.) on the northern or sunny slopes of the Cordillera -Vilcapampa above Pampaconas, a thousand feet below the snowline. The -grass is remarkably profuse and supports the flocks and herds of a -pastoral population.</p></td></tr></table> -</div> - -<p><a name="fig_98" id="fig_98"></a></p> - -<p><a name="fig_99" id="fig_99"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_154b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_154b_sml.jpg" width="317" height="210" alt="Fig. 98—Dense ground cover, typical trees, epiphytes, -and parasites of the tropical rain forest at 2,500-3,000 feet between -Pongo de Mainique and Rosalina." /></a> -<br /> - -<table border="0" cellpadding="5" cellspacing="0" summary=""> -<tr valign="top"><td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 98—Dense ground cover, typical trees, epiphytes, -and parasites of the tropical rain forest at 2,500-3,000 feet between -Pongo de Mainique and Rosalina.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig. 99</span>—The Urubamba Valley below Santa Ana. On the dry -valley floor is a mixed growth of scattered trees, shrubs and grass, -with shrubs predominating. Higher up a more luxuriant ravine vegetation -appears. On the upper spurs true forest patches occupy the shady slopes. -Finally, in the zone of clouds at the top of the picture is a continuous -forest. See <a href="#fig_17">17</a> , for regional applications.</p></td></tr></table> -</div> - -<p>Combined with these topographic features are certain climatic features -of equal precision. Between 7,000 and 13,000 feet is a zone of clouds -oftentimes marked out as distinctly as the belt of fog on the Peruvian -coast.<a name="FNanchor_26_26" id="FNanchor_26_26"></a><a href="#Footnote_26_26" class="fnanchor">[26]</a> Rarely does it extend across the valley. Generally it hangs -as a white belt on the opposite walls. When the up-valley winds of day -begin to blow it drifts up-valley, oftentimes to be dissolved as it -strikes the warmer slopes of the upper valley, just as its settling -under surface is constantly being dissolved in the warm dry air of the -valley floor. Where the precipitation is heaviest there is a belt of -woodland—dark, twisted trees, moss-draped, wet—a Druid forest. Below -and above the woodland are grassy slopes. At Incahuasi a spur runs out -and down until at last it terminates between two deep canyons. No -ordinary wells could be successful. The ground water must be a thousand -feet down, so a canal, a tiny thing only a few inches wide and deep, has -been cut away up to a woodland stream. Thence the water is carried down -by a contour-like course out of the woodland into the pasture, and so -down to the narrow part of the spur where there is pasture but no -springs or streams.</p> - -<p>Corn fields surround the few scattered habitations that have been built -just above the break or shoulder on the valley wall where the woodland -terminates, and there are fine grazing lands. The trails follow the -upper slopes whose gentler contours permit a certain liberty of -movement. Then the way plunges downward over a staircase trail, over -steep boulder-strewn slopes to the arid floor of a tributary where -nature has built a graded route. And so to the still more arid floor of -the main valley, where the ample and moderate slopes of the alluvial -fans with their mountain streams permit plantation agriculture again to -come in.</p> - -<p>To these three climates, the western border type, the eastern<a name="page_156" id="page_156"></a> border -type, and the inter-Andean type, we have given chief attention because -they have the most important human relations. The statistical records of -the expedition as shown in the curves and the discussion that -accompanies them give attention to those climatic features that are of -theoretical rather than practical interest, and are largely concerned -with the conventional expression of the facts of weather and climate. -They are therefore combined in the following chapter which is devoted -chiefly to a technical discussion of the meteorology as distinguished -from the climatology of the Peruvian Andes.<a name="page_157" id="page_157"></a></p> - -<h3><a name="CHAPTER_X" id="CHAPTER_X"></a>CHAPTER X<br /><br /> -METEOROLOGICAL RECORDS FROM THE PERUVIAN ANDES</h3> - -<h4><span class="smcap">Introduction</span></h4> - -<p>The data in this chapter, on the weather and climate of the Peruvian -Andes, were gathered under the usual difficulties that accompany the -collection of records at camps scarcely ever pitched at the same -elevation or with the same exposure two days in succession. Some of -them, and I may add, the best, were contributed by volunteer observers -at fixed stations. The observations are not confined to the field of the -Yale Peruvian Expedition of 1911, but include also observations from -Professor Hiram Bingham’s Expeditions of 1912 and 1914-15, together with -data from the Yale South American Expedition of 1907. In addition I have -used observations supplied by the Morococha Mining Company through J. P. -Little. Some hitherto unpublished observations from Cochabamba, Bolivia, -gathered by Herr Krüger at considerable expense of money for instruments -and of time from a large business, are also included, and he deserves -the more credit for his generous gift of these data since they were -collected for scientific purposes only and not in connection with -enterprises in which they might be of pecuniary value. My only excuse to -Herr Krüger for this long delay in publication (they were put into my -hands in 1907) is that I have wanted to publish his data in a dignified -form and also to use them for comparison with the data of other climatic -provinces.</p> - -<p>A further word to the reader seems necessary before he examines the -following curves and tables. It would be somewhat audacious to assume -that these short-term records have far-reaching importance. Much of -their value lies in their organization with respect to the data already -published on the climate of Peru. But since this would require a delay -of several years in their publication it seems better to present them -now in their simplest form. After all, the professional climatologist, -to whom they are<a name="page_158" id="page_158"></a> chiefly of interest, scarcely needs to have such -organization supplied to him. Then, too, we hope that there will become -available in the next ten or fifteen years a vastly larger body of -climatological facts from this region. When these have been collected we -may look forward to a volume or a series of volumes on the “Climate of -Peru,†with full statistical tables and a complete discussion of them. -That would seem to be the best time for the reproduction of the detailed -statistics now on hand. It is only necessary that there shall be -sufficient analysis of the data from time to time to give a general idea -of their character and to indicate in what way the scope of the -observations might profitably be extended. I have, therefore, taken from -the available facts only such as seem to me of the most importance -because of their unusual character or their special relations to the -boundaries of plant provinces or of the so-called “natural regions†of -geography.</p> - -<h4><span class="smcap">Machu Picchu</span><span class="font-size:100%;"> -<a name="FNanchor_27_27" id="FNanchor_27_27"></a><a href="#Footnote_27_27" class="fnanchor">[27]</a> -</span></h4> - -<p>The following observations are of special interest in that they -illustrate the weather during the southern winter and spring at the -famous ruins of Machu Picchu in the Canyon of Torontoy. The elevation is -8,500 feet. The period they cover is too short to give more than a hint -of the climate or of the weather for the year. It extends from August -20, 1912, to November 6, 1912 (79 days).</p> - -<table border="1" cellpadding="0" cellspacing="0" summary=""> -<tr><td colspan="7" align="center" -style="border:none;">ANALYTICAL TABLE OF WIND DIRECTIONS, MACHU PICCHU, 1912</td></tr> -<tr><td rowspan="3">Direction of wind</td> -<td colspan="6" align="center">Number of Observations </td></tr> -<tr> -<td align="center" class="nbb">Aug. 20 </td> -<td align="center" class="nbb">—</td> -<td align="center" class="nbb"> Sept. 30</td> -<td align="center" class="nbb"> Oct. 1</td> -<td align="center" class="nbb"> —</td> -<td align="center" class="nbb"> Nov. 6</td></tr> - -<tr><td align="center"> 7 a. m.</td> -<td align="center">1 p. m.</td> -<td align="center"> 7 p. m.</td> -<td align="center"> 7 a. m.</td><td> 1 p. m.</td><td> 7 p. m.</td></tr> -<tr><td>N.</td><td align="right"> 5</td><td align="right"> 2 </td><td align="right">5</td><td align="right"> 2</td><td align="right"> —</td><td align="right"> —</td></tr> -<tr><td>N.W.</td><td align="right"> 9 </td><td align="right">10 </td><td align="right">14</td><td align="right"> 4 </td><td align="right">6</td><td align="right"> 11</td></tr> -<tr><td>W.</td><td align="right"> —</td><td align="right"> 1</td><td align="right"> 2</td><td align="right"> 2 </td><td align="right">2</td><td align="right"> 4</td></tr> -<tr><td>S. W.</td><td align="right"> —</td><td align="right"> — </td><td align="right">1</td><td align="right"> 1</td><td align="right"> 1</td><td align="right"> 6</td></tr> -<tr><td>S.</td><td align="right"> — </td><td align="right">— </td><td align="right">1</td><td align="right"> —</td><td align="right"> —</td><td align="right"> 2</td></tr> -<tr><td>S. E.</td><td align="right"> 4 </td><td align="right">2</td><td align="right"> 1</td><td align="right"> —</td><td align="right">—</td><td align="right"> 3</td></tr> -<tr><td>E.</td><td align="right"> 6 </td><td align="right">3 </td><td align="right">3</td><td align="right"> 12</td><td align="right"> 4</td><td align="right"> 4</td></tr> -<tr><td>N. E.</td><td align="right"> 8</td><td align="right"> 7</td><td align="right"> 6</td><td align="right"> 4</td><td align="right"> 1 </td><td align="right">3</td></tr> -<tr><td>CALM</td><td align="right"> —</td><td align="right"> —</td><td align="right"> 2</td><td align="right"> 5</td><td align="right"> 3 </td><td align="right">3</td></tr> -</table> - -<p><a name="page_159" id="page_159"></a></p> - -<table border="1" cellpadding="0" cellspacing="0" summary=""> - -<tr><td rowspan="3">Direction of wind</td> -<td colspan="6" align="center">Percentages of Total Observation<a name="FNanchor_28_28" -id="FNanchor_28_28"></a><a href="#Footnote_28_28" class="fnanchor">[28]</a></td></tr> - -<tr><td align="center" class="nbb">Aug. 20 </td> -<td align="center" class="nbb">—</td> -<td align="center" class="nbb"> Sept. 30</td> -<td align="center" class="nbb"> Oct. 1</td> -<td align="center" class="nbb"> —</td> -<td align="center" class="nbb"> Nov. 6</td></tr> - -<tr><td align="center"> 7 a. m.</td> -<td align="center">1 p. m.</td> -<td align="center"> 7 p. m.</td> -<td align="center"> 7 a. m.</td><td> 1 p. m.</td><td> 7 p. m.</td></tr> -<tr><td>N.</td><td align="right"> 15.6</td><td align="right"> 8.0 </td><td align="right">14.2</td><td align="right"> 6.7</td><td align="right"> ——</td><td align="right"> ——</td></tr> -<tr><td>N. W.</td><td align="right"> 28.1</td><td align="right"> 40.0</td><td align="right"> 40.0</td><td align="right"> 13.3</td><td align="right"> 35.3 </td><td align="right">30.7</td></tr> -<tr><td>W.</td><td align="right"> ——</td><td align="right"> 4.0</td><td align="right"> 5.7</td><td align="right"> 6.7</td><td align="right"> 11.8 </td><td align="right">11.1</td></tr> -<tr><td>S. W.</td><td align="right"> ——</td><td align="right"> ——</td><td align="right"> 2.8</td><td align="right"> 3.3</td><td align="right"> 5.9 </td><td align="right">16.7</td></tr> -<tr><td>S.</td><td align="right"> ——</td><td align="right"> ——</td><td align="right"> 2.8</td><td align="right"> ——</td><td align="right"> ——</td><td align="right"> 5.5</td></tr> -<tr><td>S. E.</td><td align="right"> 12.5</td><td align="right"> 8.0</td><td align="right"> 2.8</td><td align="right"> ——</td><td align="right"> ——</td><td align="right"> 8.3</td></tr> -<tr><td>E.</td><td align="right"> 18.8</td><td align="right"> 12.0 </td><td align="right">8.6</td><td align="right"> 40.0</td><td align="right"> 23.5</td><td align="right"> 11.1</td></tr> -<tr><td>N. E.</td><td align="right"> 25.0</td><td align="right"> 28.0</td><td align="right">17.1</td><td align="right"> 13.3</td><td align="right"> 5.9 </td><td align="right">8.3</td></tr> -<tr><td>CALM</td><td align="right"> ——</td><td align="right"> ——</td><td align="right"> 5.7</td><td align="right"> 16.7</td><td align="right"> 17.6</td><td align="right"> 8.3</td></tr> -</table> - -<p><a name="fig_100" id="fig_100"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_159_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_159_sml.jpg" width="210" height="85" alt="Fig. 100—Wind roses for Machu Picchu, August 20 to -November 6, 1912." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 100—Wind roses for Machu Picchu, August 20 to -November 6, 1912.</p> -</div> - -<p>The high percentage of northwest winds during afternoon hours is due to -the up-valley movement of the air common to almost all mountain borders. -The air over a mountain slope is heated more than the free air at the -same elevation over the plains (or lower valley); hence a barometric -gradient towards the mountain becomes established. At Machu Picchu the -Canyon of Torontoy trends northwest, making there a sharp turn from an -equally sharp northeast bend directly upstream. The easterly components -are unrelated to the topography. They represent the trades. If a wind -rose were made for still earlier morning hours these winds would be more -faithfully represented. That an easterly and northeasterly rather than a -southeasterly direction should be assumed by the trades is not difficult -to believe when we consider the trend of the Cordillera—southeast to -northwest. The observations<a name="page_160" id="page_160"></a> from here down to the plains all show that -there is a distinct change in wind direction in sympathy with the larger -features of the topography, especially the deep valleys and canyons, the -trades coming in from the northeast.</p> - -<h4>CLOUDINESS</h4> - -<p>It will be seen that the sky was overcast or a fog lay in the valley 53 -per cent of the time at early morning hours. Even at noon the sky was at -no time clear, and it was more than 50 per cent clear only 18 per cent -of the time. Yet this is the so-called “dry†season of the valleys of -the eastern Andes. The rainfall record is in close sympathy. In the 79 -days’ observations rain is recorded on 50 days with a greater proportion -from mid-September to the end of the period (November 6), a distinct -transition toward the wet period that extends from December to May. The -approximate distribution of the rains by hours of observation (7 <span class="smcap">A. M.</span>, -1 <span class="smcap">P. M.</span>, 7 <span class="smcap">P. M.</span>) was in the ratio 4:3:6. Also the greatest number of -heavy showers as well as the greatest number of showers took place in -the evening. The rainfall was apparently unrelated to wind direction in -the immediate locality, though undoubtedly associated with the regional -movement of the moist plains air toward the mountains. All these facts -regarding clouds and rain plainly show the location of the place in the -belt of maximum precipitation. There is, therefore, a heavy cover of -vegetation. While the situation is admirable for defence, the murky -skies and frequent fogs somewhat offset its topographic surroundings as -a lookout.</p> - -<table border="1" cellpadding="0" cellspacing="0" summary=""> -<tr><td align="center" -style="border:none;" -colspan="13">ANALYTICAL TABLE OF THE STATE OF THE SKY, MACHU PICCHU, 1912</td></tr> -<tr><td> </td> -<td align="center" colspan="2"> Morning</td> -<td align="center" colspan="2"> Total</td> -<td align="center" colspan="2" -style="border-left:3px black double;"> Noon</td> -<td align="center" colspan="2"> Total</td> -<td align="center" colspan="2" -style="border-left:3px black double;"> Evening</td> -<td align="center" colspan="2"> Total</td></tr> -<tr><td> </td> -<td align="right">Aug.-Sept.</td> -<td align="right">Oct.-Nov.</td> -<td align="right">Days</td> -<td align="center"> %</td> -<td align="right" -style="border-left:3px black double;">Aug.-Sept.</td> -<td align="right">Oct.-Nov.</td> -<td align="right"> Days</td> -<td align="center"> %</td> -<td align="right" -style="border-left:3px black double;">Aug.-Sept.</td> -<td align="right">Oct.-Nov.</td> -<td align="right">Days</td> -<td align="center"> %</td></tr> -<tr><td>Foggy</td> -<td align="right"> 3.0</td> -<td align="right"> 14.0</td> -<td align="right"> 17.0</td> -<td align="right"> 28.4</td> -<td align="right" -style="border-left:3px black double;"> 1.0</td> -<td align="right"> —</td> -<td align="right"> 1.0</td> -<td align="right"> 2.6</td> -<td align="right" -style="border-left:3px black double;"> 1.0</td> -<td align="right"> 2.0</td> -<td align="right"> 3.0</td> -<td align="right"> 4.3</td></tr> -<tr><td>Overcast</td> -<td align="right"> 12.0</td> -<td align="right"> 3.0</td> -<td align="right"> 15.0</td> -<td align="right"> 25.0</td> -<td align="right" -style="border-left:3px black double;"> 6.0</td> -<td align="right"> 8.0</td> -<td align="right"> 14.0</td> -<td align="right"> 36.8</td> -<td align="right" -style="border-left:3px black double;"> 13.0</td> -<td align="right"> 11.0</td> -<td align="right"> 24.0</td> -<td align="right"> 34.8</td></tr> -<tr><td>50-100% cloudy</td> -<td align="right"> 4.0</td> -<td align="right"> 10.0</td> -<td align="right"> 14.0</td> -<td align="right"> 23.3</td> -<td align="right" -style="border-left:3px black double;"> 0.0</td> -<td align="right"> 7.0</td> -<td align="right"> 16.0</td> -<td align="right"> 42.2</td> -<td align="right" -style="border-left:3px black double;"> 8.0</td> -<td align="right"> 15.0</td> -<td align="right"> 23.0</td> -<td align="right"> 33.3</td></tr> -<tr><td>0-50% cloudy</td> -<td align="right"> 6.0</td> -<td align="right"> 4.0</td> -<td align="right"> 10.0</td> -<td align="right"> 16.7</td> -<td align="right" -style="border-left:3px black double;"> 5.0</td> -<td align="right"> 2.0</td> -<td align="right"> 7.0</td> -<td align="right"> 18.4</td> -<td align="right" -style="border-left:3px black double;"> 9.0</td> -<td align="right"> 4.0</td> -<td align="right"> 13.0</td> -<td align="right"> 18.8</td></tr> -<tr><td>Clear</td> -<td align="right"> 3.0</td> -<td align="right"> 1.0</td> -<td align="right"> 4.0</td> -<td align="right"> 6.6</td> -<td align="right" -style="border-left:3px black double;"> 0.0</td> -<td align="right"> 0.0</td> -<td align="right"> 0.0</td> -<td align="right"> 0.0</td> -<td align="right" -style="border-left:3px black double;"> 3.0</td> -<td align="right"> 3.0</td> -<td align="right"> 6.0</td> -<td align="right"> 8.8</td></tr> -</table> - -<p><a name="page_161" id="page_161"></a></p> - -<h4><span class="smcap">Santa Lucia</span><span style="font-size:100%;"> -<a name="FNanchor_29_29" id="FNanchor_29_29"></a><a href="#Footnote_29_29" class="fnanchor">[29]</a> -</span></h4> - -<p>Santa Lucia is a mining center in the province of Puno (16° S.), at the -head of a valley here running northeast towards Lake Titicaca. Its -elevation, 15,500 feet above sea level, confers on it unusual interest -as a meteorological station. A thermograph has been installed which -enables a closer study of the temperature to be made than in the case of -the other stations. It is unfortunate, however, that the observations -upon clouds, wind directions, etc., should not have been taken at -regular hours. The time ranges from 8.30 to 11.30 for morning hours and -from 2.30 to 5.30 for afternoon. The observations cover portions of the -years 1913 and 1914.</p> - -<h4>TEMPERATURE</h4> - -<p>Perhaps the most striking features of the weather of Santa Lucia are the -highly regular changes of temperature from night to day or the uniformly -great diurnal range and the small differences of temperature from day to -day or the low diurnal variability. For the whole period of nearly a -year the diurnal variability never exceeds 9.5° F. (5.3° C.) and for -days at a time it does not exceed 2-3° F. (1.1°-1.7° C.). The most -frequent variation, occurring on 71 per cent of the total number of -days, is from 0-3° F., and the mean for the year gives the low -variability of 1.9° F. (1.06° C.). These facts, illustrative of a type -of weather comparable in <i>uniformity</i> with low stations on the Amazon -plains, are shown in the table following as well as in the accompanying -curves.</p> - -<table border="1" cellpadding="1" cellspacing="0" summary=""> -<tr><td align="center" -colspan="13" -style="border:none;">FREQUENCY OF THE DIURNAL VARIABILITY, SANTA LUCIA, 1913-14</td></tr> -<tr><td align="right">Degrees F.</td> -<td align="center">May</td> -<td align="center">June</td> -<td align="center">July</td> -<td align="center">Aug.</td> -<td align="center">Sept.</td> -<td align="center">Oct.</td> -<td align="center">Nov.</td> -<td align="center">Dec.</td> -<td align="center">Jan.</td> -<td align="center">Feb.</td> -<td align="center">March</td> -<td align="center" -style="border-left:3px double black;">Total No.<br /> of days</td></tr> -<tr><td align="right">0</td> -<td align="right"> —</td> -<td align="right"> 2</td> -<td align="right"> 6</td> -<td align="right"> 3</td> -<td align="right"> 4</td> -<td align="right"> 6</td> -<td align="right"> 2</td> -<td align="right"> —</td> -<td align="right"> 1</td> -<td align="right"> —</td> -<td align="right"> 2</td> - -<td align="right" -style="border-left:3px double black;"> 26</td></tr> -<tr><td align="right">0-1</td> -<td align="right"> 2</td> -<td align="right"> 7</td> -<td align="right"> 7</td> -<td align="right"> 5</td> -<td align="right"> 6</td> -<td align="right"> 4</td> -<td align="right"> 8</td> -<td align="right"> 12</td> -<td align="right"> 14</td> -<td align="right"> 9</td> -<td align="right"> 5</td> - -<td align="right" -style="border-left:3px double black;"> 79</td></tr> -<tr><td align="right">1-2</td> -<td align="right"> 11</td> -<td align="right"> 5</td> -<td align="right"> 7</td> -<td align="right"> 11</td> -<td align="right"> 7</td> -<td align="right"> 8</td> -<td align="right"> 5</td> -<td align="right"> 5</td> -<td align="right"> 4</td> -<td align="right"> 9</td> -<td align="right"> 13</td> - -<td align="right" -style="border-left:3px double black;"> 85</td></tr> -<tr><td align="right">2-3</td> -<td align="right"> 2</td> -<td align="right"> 8</td> -<td align="right"> 8</td> -<td align="right"> 9</td> -<td align="right"> 3</td> -<td align="right"> 7</td> -<td align="right"> 7</td> -<td align="right"> 5</td> -<td align="right"> 5</td> -<td align="right"> 4</td> -<td align="right"> 6</td> - -<td align="right" -style="border-left:3px double black;"> 64</td></tr> -<tr><td align="right">3-4</td> -<td align="right"> 4</td> -<td align="right"> 4</td> -<td align="right"> 2</td> -<td align="right"> 1</td> -<td align="right"> 4</td> -<td align="right"> 1</td> -<td align="right"> 3</td> -<td align="right"> 6</td> -<td align="right"> 2</td> -<td align="right"> 4</td> -<td align="right"> 2</td> - -<td align="right" -style="border-left:3px double black;"> 33</td></tr> -<tr><td align="right">4-5</td> -<td align="right"> 1</td> -<td align="right"> 3</td> -<td align="right"> 1</td> -<td align="right"> —</td> -<td align="right"> 2</td> -<td align="right"> 1</td> -<td align="right"> 3</td> -<td align="right"> —</td> -<td align="right"> 2</td> -<td align="right"> 1</td> -<td align="right"> 1</td> - -<td align="right" -style="border-left:3px double black;"> 15</td></tr> -<tr><td align="right">Over 5</td> -<td align="right"> —</td> -<td align="right"> 1</td> -<td align="right"> —</td> -<td align="right"> 2</td> -<td align="right"> 4</td> -<td align="right"> 4</td> -<td align="right"> 2</td> -<td align="right"> 2</td> -<td align="right"> 3</td> -<td align="right"> 1</td> -<td align="right"> —</td> - -<td align="right" -style="border-left:3px double black;"> 19</td></tr> -<tr><td align="right">Days per<br /> month</td> -<td align="right"> 20</td> -<td align="right"> 30</td> -<td align="right"> 31</td> -<td align="right"> 31</td> -<td align="right"> 30</td> -<td align="right"> 31</td> -<td align="right"> 30</td> -<td align="right"> 30</td> -<td align="right"> 31</td> -<td align="right"> 28</td> -<td align="right"> 29</td> - -<td align="right" -style="border-left:3px double black;"> 321</td></tr> -</table> - -<p><a name="page_162" id="page_162"></a></p> - -<p>If we take the means of the diurnal variations by months we have a still -more striking curve showing how little change there is between -successive days. June and December are marked by humps in the curve. -They are the months of extreme weather when for several weeks the -temperatures drop to their lowest or climb to their highest levels. -Moreover, there is at these lofty stations no pronounced lag of the -maximum and minimum temperatures for the year behind the times of -greatest and least heating such as we have at lower levels in the -temperate zone. Thus we have the highest temperature for the year on -December 2, 70.4° F. (21.3° C.), the lowest on June 3, 0.2° F. (—17.7° -C.). The daily maxima and minima have the same characteristic. Radiation -is active in the thin air of high stations and there is a very direct -relation between the times of greatest heat received and greatest heat -contained. The process is seen at its best immediately after the sun is -obscured by clouds. In five minutes I have observed the temperature drop -20° F. (11.1° C.) at 16,000 feet (4,877 m.); and a drop of 10° F. (5.6° -C.) is common anywhere above 14,000 feet (4,267 m.). In the curves of -daily maximum and minimum temperatures we have clearly brought out the -uniformity with which the maxima of high-level stations rise to a mean -level during the winter months (May-August). Only at long intervals is -there a short series of cloudy days when the maximum is 10°-12° F. -(5.6°-6.7° C.) below the normal and the minimum stands at abnormally -high levels. Since clouds form at night in quite variable amounts—in -contrast to the nearly cloudless days—there is a far greater -variability among the minimum temperatures. Indeed the variability of -the winter minima is greater than that of the summer minima, for at the -latter season the nightly cloud cover imposes much more stable -atmospheric temperatures. The summer maxima have a greater degree of -variability. Several clear days in succession allow the temperature to -rise from 5°-10° F. (2.8°-5.6° C.) above the winter maxima. But such -extremes are rather strictly confined to the height of the summer -season—December and January. For the rest of the summer the maxima rise -only<a name="page_163" id="page_163"></a> a few degrees above those of the winter. This feature of the -climate combines with a December maximum of rainfall to limit the period -of most rapid plant growth to two months. Barley sown in late November -could scarcely mature by the end of January, even if growing on the -Argentine plains and much less at an elevation which carries the night -temperatures below freezing at least once a week and where the mean -temperature hovers about 47° F. (8.3° C.). The proper conditions for -barley growing are not encountered above 13,000 to 13,500 feet and the -farmer cannot be certain that it will ripen above 12,500 feet in the -latitude of Santa Lucia.</p> - -<p>The curve of mean monthly temperatures expresses a fact of great -importance in the plant growth at high situations in the Andes—the -sharp break between the winter and summer seasons. There are no real -spring and autumn seasons. This is especially well shown in the curve -for non-periodic mean monthly range of temperature for the month of -October. During the half of the year that the sun is in the southern -hemisphere the sun’s noonday rays strike Santa Lucia at an angle that -varies between 0° and 16° from the vertical. The days and nights are of -almost equal length and though there is rapid radiation at night there -is also rapid insolation by day. When the sun is in the northern -hemisphere the days are shortened from one to two hours and the angle of -insolation decreased, whence the total amount of heat received is so -diminished that the mean monthly temperature lies only a little above -freezing point. In winter the quiet pools beside the springs freeze over -long before dark as the hill shadows grow down into the high-level -valleys, and by morning ice also covers the brooks and marshes. Yet the -sun and wind-cured <i>ichu</i> grass lives here, pale green in summer, -straw-yellow in winter. The tola bush also grows rather abundantly. But -we are almost at the upper limit of the finer grasses and a few hundred -feet higher carries one into the realm of the snowline vegetation, -mosses and lichens and a few sturdy flowering plants.</p> - -<p>For convenience in future comparative studies the absolute extremes are -arranged in the following table:</p> - -<p><a name="fig_101" id="fig_101"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_163a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_163a_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_163a_sml.jpg" width="430" height="207" alt="Fig. 101 A—DIURNAL TEMPERATURE, SANTA LUCIA, 1913-’14 -C—DIURNAL RANGE OF TEMPERATURE, SANTA LUCIA, 1913-’14 E—DIURNAL -VARIABILITY OF TEMPERATURE, SANTA LUCIA, 1913-’14 B—MEAN MONTHLY -TEMPERATURE, SANTA LUCIA, 1913-’14 D—MONTHLY MEANS OF DIURNAL RANGE OF -TEMPERATURE, SANTA LUCIA, 1913-’14 F—RELATIVE HUMIDITY, SANTA LUCIA, -1913-’14" /> -</div> - -<p><a name="page_164" id="page_164"></a></p> - -<table border="1" cellpadding="1" cellspacing="0" summary=""> -<tr><td align="center" colspan="5" -style="border:none;">ABSOLUTE MONTHLY EXTREMES, SANTA LUCIA, 1913-14</td></tr> -<tr><td align="center">Date</td><td align="center"> Highest</td><td align="center"></td><td align="center"> Lowest</td><td align="center"> Date</td></tr> -<tr><td align="left">May<a name="FNanchor_30_30" id="FNanchor_30_30"></a><a href="#Footnote_30_30" class="fnanchor">[30]</a> (12)</td><td align="left"> 62° F.</td><td align="left"></td><td align="left"> 9° F.</td><td align="left"> May (25, 26)</td></tr> -<tr><td align="left">June (4 days)</td><td align="left"> 60° F.</td><td align="left"></td><td align="left"> 0.2° F.</td><td align="left"> June (3)</td></tr> -<tr><td align="left">July (4 days, 31)</td><td align="left"> 60° F.</td><td align="left"></td><td align="left"> 5° F.</td><td align="left"> July (8)</td></tr> -<tr><td align="left">Aug. (8, 26)</td><td align="left"> 62° F.</td><td align="left"></td><td align="left"> 4° F.</td><td align="left"> Aug. (4, 5)</td></tr> -<tr><td align="left">Sept. (several days)</td><td align="left"> 62° F.</td><td align="left"></td><td align="left"> 7° F.</td><td align="left"> Sept. (4 days)</td></tr> -<tr><td align="left">Oct. (24)</td><td align="left"> 63° F.</td><td align="left"></td><td align="left"> 10° F.</td><td align="left"> Oct. (12, 13)</td></tr> -<tr><td align="left">Nov. (11)<a name="FNanchor_31_31" id="FNanchor_31_31"></a><a href="#Footnote_31_31" class="fnanchor">[31]</a></td><td align="left"> 63° F.</td><td align="left"></td><td align="left"> 24.0° F.</td><td align="left"> Nov. (29)</td></tr> -<tr><td align="left">Dec. (2)</td><td align="left"> 70.4° F.</td><td align="left"></td><td align="left"> 22.2° F.</td><td align="left"> Dec. (14)</td></tr> -<tr><td align="left">Jan. (19)</td><td align="left"> 69.5° F.</td><td align="left"></td><td align="left"> 26.5° F.</td><td align="left"> Jan. (3, 15)</td></tr> -<tr><td align="left">Feb. (16, 18)</td><td align="left"> 63.2° F.</td><td align="left"></td><td align="left"> 30.5° F.</td><td align="left"> Feb. (23)</td></tr> -<tr><td align="left">March (8)</td><td align="left"> 68.4° F.</td><td align="left"></td><td align="left"> 28.5° F.</td><td align="left"> March (6)</td></tr> -</table> - -<h4>RAINFALL</h4> - -<p>The rainfall record for Santa Lucia is for the year beginning November, -1913. For this period the precipitation amounts to 24.9 inches of which -over 85 per cent fell in the rainy season from November to March. Most -of the rain fell during the violent afternoon tempests that characterize -the summer of these high altitudes.</p> - -<p>The rainfall of Santa Lucia for this first year of record approximates -closely to the yearly mean of 23.8 inches for the station of Caylloma in -the adjacent province of that name. Caylloma is the center of a mining -district essentially similar to Santa Lucia though the elevation of its -meteorological station, 14,196 feet (4,330 m.), is lower. It is one of -the few Peruvian stations for which a comparatively long series of -records is available. The <i>BoletÃn de la Sociedad Geográfica de -Lima</i><a name="FNanchor_32_32" id="FNanchor_32_32"></a><a href="#Footnote_32_32" class="fnanchor">[32]</a> contains a résumé of rainfall and temperature for seven years, -1896-7 to 1902-3. Later data may be found in subsequent volumes of the -same publication but they have not been summarized or in any way -prepared for analysis and they contain several typographical errors. A -graphic representation of the monthly rainfall for the earlier period is -here reproduced from the <i>BoletÃn de minas del Perú</i>.<a name="FNanchor_33_33" id="FNanchor_33_33"></a><a href="#Footnote_33_33" class="fnanchor">[33]</a> The<a name="page_165" id="page_165"></a><a name="page_166" id="page_166"></a> amount -of precipitation fluctuates considerably from year to year. For the -earlier period, with a mean of 23.8 inches the minimum (1896-7) was 8 -inches and the maximum (1898-9) 36 inches. For the later period, 1903-4 -to 1910-11, with a mean of 29.5 inches the minimum (1904-5) was 17.5 -inches and the maximum (1906-7) was 43 inches.</p> - -<p><a name="fig_102" id="fig_102"></a></p> - -<p><a name="fig_103a" id="fig_103a"></a></p> -<p><a name="fig_103b" id="fig_103b"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_165_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_165_sml.jpg" width="197" height="288" alt="Fig. 102—Monthly rainfall of Santa Lucia for the year -November, 1913, to October, 1914. No rain fell in July and August." /></a> -<br /> - -<p class="caption"><span class="smcap">Fig</span>. 102—Monthly rainfall of Santa Lucia for the year -November, 1913, to October, 1914. No rain fell in July and August.</p> - -<p class="caption"><span class="smcap">Fig. 103A</span>—Maximum, mean and minimum monthly rainfall of -Caylloma for the period 1896-7 to 1902-3. July was absolutely rainless. -Caylloma is situated immediately east of the crest of the Maritime -Cordillera in a position similar to that of Santa Lucia (see <a href="#fig_66">Fig. 66</a>).</p> - -<p class="caption"><span class="smcap">Fig. 103B</span>—Annual rainfall of Caylloma for the periods -1896-7 to 1902-3; 1903-4 to 1910-11 and for 1915-6 (incomplete: May and -June, months of low rainfall, are missing). Means for the respective -seven and eight year periods are shown and the rainfall of Santa Lucia -for the single observation year is inserted for comparison.</p> -</div> - -<table border="1" cellpadding="1" cellspacing="0" summary=""> -<tr><td align="center" colspan="5" -style="border:none;">RAINFALL, SANTA LUCIA, NOV. 1913 TO OCT. 1914</td></tr> -<tr><td align="right"> </td> -<td align="right"> No of fine days</td> -<td align="right"> No. of rainy days</td> -<td align="right"> Max. for single day</td> -<td align="right"> Total rainfall in inches</td></tr> -<tr><td align="left">November</td> -<td align="right"> 9</td> -<td align="right"> 21</td> -<td align="right"> 1.150</td> -<td align="right"> 4.264<a name="FNanchor_34_34" id="FNanchor_34_34"></a><a href="#Footnote_34_34" class="fnanchor">[34]</a></td></tr> -<tr><td align="left">December</td> -<td align="right"> 16</td> -<td align="right"> 15</td> -<td align="right"> .700</td> -<td align="right"> 6.439</td></tr> -<tr><td align="left">January</td> -<td align="right"> 17</td> -<td align="right"> 14</td> -<td align="right"> .610</td> -<td align="right"> 3.313</td></tr> -<tr><td align="left">February</td> -<td align="right"> 9</td> -<td align="right"> 17</td> -<td align="right"> .910</td> -<td align="right"> 2.975</td></tr> -<tr><td align="left">March</td> -<td align="right"> 11</td> -<td align="right"> 20</td> -<td align="right"> 1.102</td> -<td align="right"> 4.381</td></tr> -<tr><td align="left">April</td> -<td align="right"> 17</td> -<td align="right"> 13</td> -<td align="right"> 0.31</td> -<td align="right"> 0.92</td></tr> -<tr><td align="left">May</td> -<td align="right"> 8</td> -<td align="right"> 23</td> -<td align="right"> 0.35</td> -<td align="right"> 1.63</td></tr> -<tr><td align="left">June</td> -<td align="right"> 27</td> -<td align="right"> 3</td> -<td align="right"> 0.05</td> -<td align="right"> 0.07</td></tr> -<tr><td align="left">July</td> -<td align="right"> 31</td> -<td align="right"> 0</td> -<td align="right"> 0.00</td> -<td align="right"> 0.00</td></tr> -<tr><td align="left">August</td> -<td align="right"> 31</td> -<td align="right"> 0</td> -<td align="right"> 0.00</td> -<td align="right"> 0.00</td></tr> -<tr><td align="left">September</td> -<td align="right"> 23</td> -<td align="right"> 7</td> -<td align="right"> 0.05</td> -<td align="right"> 0.35</td></tr> -<tr><td align="left">October</td> -<td align="right"> 21</td> -<td align="right"> 10</td> -<td align="right"> 0.14</td> -<td align="right"> 0.56</td></tr> -<tr><td align="center">Total</td> -<td align="right"> </td> -<td align="right"> </td> -<td align="right"> </td> -<td align="right"> 24.902</td></tr> -</table> - -<h4>WIND</h4> - -<p>An analysis of the wind at Santa Lucia shows an excess of north and -south winds over those of all other directions. The wind-rose for the -entire period of observation (<a href="#fig_104">Fig. 104</a>) clearly expresses this fact. -When this element is removed we observe a strongly seasonal distribution -of the wind. The winter is the time of north and south winds. In summer -the winds are chiefly from the northeast or the southwest. Among single -months, August and February show this fact clearly as well as the less -decisive character of the summer (February) wind.</p> - -<p>The mean wind velocity for the month of February was 540 meters per -minute for the morning and 470 meters per minute for the afternoon. The -higher morning rate, an unusual feature of<a name="page_167" id="page_167"></a><a name="page_168" id="page_168"></a> the weather of high -stations, or indeed of wind-phenomena in general, is due, however, to -exceptional changes in wind strength on two days of the month, the 16th -and 25th, when the velocity decreased from a little less than a thousand -meters per minute in the morning to 4 and 152 meters respectively in the -afternoon. More typical is the March record for 1914 at Santa Lucia, -when the wind was <i>always</i> stronger in the afternoon than in the -morning, their ratios being 550 to 510.</p> - -<p><a name="fig_104" id="fig_104"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_167_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_167_sml.jpg" width="211" height="313" alt="Fig. 104—Monthly wind roses for Santa Lucia, June, 1913, -to July, 1914, and composite rose for the whole period of observation." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 104—Monthly wind roses for Santa Lucia, June, 1913, -to July, 1914, and composite rose for the whole period of observation.</p> -</div> - -<h4>CLOUD</h4> - -<p>The greater strength of the afternoon wind would lead us to suppose that -the cloudiness, which in the trade-wind belt, is to so great an extent -dependent on the wind, is greatest in the afternoon. The diagrams bring -out this fact. Barely is the sky quite clear after the noon hour. Still -more striking is the contrast between the morning and afternoon if we -combine the two densest shadings of the figures. Light, high-lying -cirrus clouds are most characteristic of early morning hours. They -produce some very striking sky effects just before sunrise as they catch -the sun’s rays aloft. An hour or two after sunrise they disappear and -small cumulus clouds begin to form. These grow rapidly as the winds -begin and by afternoon become bulky and numerous. In the wet season they -grow into the nimbus and stratus types that precede a sudden downpour of -water or a furious hailstorm. This is best seen from the base of a -mountain range looking towards the crest, where the cloud-and -rain-making processes of this type are most active.</p> - -<table border="1" cellpadding="01" cellspacing="0" summary=""> -<tr><td align="center" colspan="13" -style="border:none;">CLOUD ANALYSIS, SANTA LUCIA</td></tr> -<tr><td align="center" rowspan="2">Type of cloud</td> -<td align="center" class="nbb" colspan="2"> Nov.</td> -<td align="center" class="nbb" colspan="2"> Dec.</td> -<td align="center" class="nbb" colspan="2"> Jan.</td> -<td align="center" class="nbb" colspan="2"> Feb.</td> -<td align="center" class="nbb" colspan="2"> March</td> -<td align="center" class="nbb" colspan="1"></td> -<td align="center" class="nbb" colspan="2"> Total</td></tr> -<tr> -<td align="right" colspan="2">a.m. p.m.</td> -<td align="right" colspan="2">a.m. p.m.</td> -<td align="right" colspan="2">a.m. p. m.</td> -<td align="right" colspan="2">a.m. p.m.</td> -<td align="right" colspan="2">a.m. p.m.</td> -<td align="right" colspan="1"></td> -<td align="right" colspan="2">a.m. p.m.</td></tr> -<tr><td>Cirrus</td> -<td align="right"> 6</td> -<td align="right">º 2</td> -<td align="right"> 15</td> -<td align="right"> 2</td> -<td align="right"> 9</td> -<td align="right">2</td> -<td align="right"> 5</td> -<td align="right">3</td> -<td align="right"> 6</td> -<td align="right">3</td> -<td align="right"></td> -<td align="right"> 41 </td> -<td align="right">12</td></tr> -<tr><td>Cirro-stratus</td> -<td align="right"> —</td> -<td align="right">—</td> -<td align="right"> —</td> -<td align="right">—</td> -<td align="right"> —</td> -<td align="right">—</td> -<td align="right"> —</td> -<td align="right">—</td> -<td align="right"> —</td> -<td align="right">—</td> -<td align="right"></td> -<td align="right"> —</td> -<td align="right"> —</td></tr> -<tr><td>Cirro-cumulus</td> -<td align="right"> 4</td> -<td align="right">4</td> -<td align="right"> 7</td> -<td align="right">11</td> -<td align="right"> 3</td> -<td align="right">5</td> -<td align="right"> 6</td> -<td align="right">8</td> -<td align="right"> 17 </td> -<td align="right">10</td> -<td align="right"></td> -<td align="right"> 37</td> -<td align="right"> 38</td></tr> -<tr><td>Cumulus</td> -<td align="right"> 3 </td> -<td align="right">4</td> -<td align="right"> 4 </td> -<td align="right">7</td> -<td align="right"> 10 </td> -<td align="right">9</td> -<td align="right"> 15 </td> -<td align="right">13</td> -<td align="right"> 5 </td> -<td align="right">13</td> -<td align="right"></td> -<td align="right"> 37 </td> -<td align="right">46</td></tr> -<tr><td>Strato-cumulus</td> -<td align="right"> 2</td> -<td align="right">6</td> -<td align="right"> 3</td> -<td align="right">10</td> -<td align="right"> 7</td> -<td align="right">14</td> -<td align="right"> 2</td> -<td align="right">3</td> -<td align="right"> — </td> -<td align="right">3</td> -<td align="right"></td> -<td align="right"> 14 </td> -<td align="right">36</td></tr> -<tr><td>Stratus</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> 1</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> 1</td> -<td align="right"> 1</td> -<td align="right"> 2</td> -<td align="right"></td> -<td align="right"> 2</td> -<td align="right"> 4</td></tr> -<tr><td>Nimbus</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"></td> -<td align="right"> —</td> -<td align="right"> —</td></tr> -<tr><td>Clear</td> -<td align="right"> — </td> -<td align="right">—</td> -<td align="right"> 2 </td> -<td align="right">—</td> -<td align="right"> 2 </td> -<td align="right">1</td> -<td align="right"> — </td> -<td align="right">—</td> -<td align="right"> 2</td> -<td align="right"> —</td> -<td align="right"></td> -<td align="right"> 6 </td> -<td align="right">1</td></tr> -</table> - -<p><a name="page_169" id="page_169"></a></p> - -<h4>UNUSUAL WEATHER PHENOMENA, SANTA LUCIA, 1913-14</h4> - -<p><a name="fig_105" id="fig_105"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_169_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_169_sml.jpg" width="211" height="215" alt="Fig. 105—Monthly cloudiness of Santa Lucia from January -to July, 1914. Mean cloudiness for the whole period is also shown." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 105—Monthly cloudiness of Santa Lucia from January -to July, 1914. Mean cloudiness for the whole period is also shown.</p> -</div> - -<p>The following abstracts are selected because they give some important -features of the weather not included in the preceding tables and graphs. -Of special interest are the strong contrasts between the comparatively -high temperatures of midday and the sudden “tempests†accompanied by -rain or hail that follow the strong convectional movements dependent -upon rapid and unequal heating. The furious winds drive the particles of -hail like shot. It is sometimes impossible to face them and the pack -train must<a name="page_170" id="page_170"></a> be halted until the storm has passed. Frequently they leave -the ground white with hailstones. We encountered one after another of -these “tempestades†on the divide between Lambrama and Antabamba in -1911. They are among the most impetuous little storms I have ever -experienced. The longest of them raged on the divide from two-o’clock -until dark, though in the valleys the sun was shining. Fortunately, in -this latitude they do not turn into heavy snowstorms as in the -Cordillera of northwestern Argentina, where the passes are now and then -blocked for weeks at a time and loss of human life is no infrequent -occurrence.<a name="FNanchor_35_35" id="FNanchor_35_35"></a><a href="#Footnote_35_35" class="fnanchor">[35]</a> They do, however, drive the shepherds down from the -highest slopes to the mid-valley pastures and make travel uncomfortable -if not unsafe.</p> - -<div class="blockquot"> -<p class="c">ABSTRACT FROM DAILY WEATHER OBSERVATIONS, SANTA LUCIA, 1913-14</p> - -<p class="c">NOVEMBER</p> - -<p>“Tempest†recorded 11 times, distant thunder and lightning 9 times. -Unusual weather records: “clear sky, scorching sun, good weather†-(Nov. 29); “morning sky without a single cloud, weather agreeable†-(Nov. 30).</p> - -<p class="c">DECEMBER</p> - -<p>Clear morning sky 6 times. Starry night or part of night 7 times. -Beginning of rain and strong wind frequently observed at 5-6 P.M. -“Tempest†mentioned 19 times—5 times at midnight, 8 times at 5-6 -P.M.</p> - -<p class="c">JANUARY</p> - -<p>Clear morning sky 5 times. Starry night 3 times. Rain, actual or -threatening, characteristic of afternoons. “Tempest,†generally -about 5-6 P.M., 7 times. Sun described 4 times as scorching and, -when without wind, heat as stifling. Weather once “agreeable.â€</p> - -<p class="c">FEBRUARY</p> - -<p>Constant cloud changes, frequent afternoon or evening rains. -“Tempest,†generally 4 P.M. and later, 16 times.<a name="page_171" id="page_171"></a></p> - -<p class="c">MARCH</p> - -<p>Twice clear morning skies, once starry night. Scorching sun and -stifling heat on one occasion. “Tempest,†generally in late -afternoon and accompanied by hail, 19 times. Observed 3 or 4 times -a strong, “land breeze†(terral) of short duration (15-20 mins.) -and at midnight.</p></div> - -<h4><span class="smcap">Morococha</span></h4> - -<p>Morococha, in the Department of Ancachs, Peru, lies in 76° 11′ west -longitude and 11° 45′ south latitude and immediately east of the crest -line of the Maritime Cordillera. It is 14,300 feet above sea level, and -is surrounded by mountains that extend from 1,000 to 3,000 feet higher. -The weather records are of special interest in comparison with those of -Santa Lucia. Topographically the situations of the two stations are -closely similar hence we may look for climatic differences dependent on -the latitudinal difference. This is shown in the heavier rainfall of -Morococha, 4° nearer the equatorial climatic zone. (For location see -Fig. 66.)</p> - -<p>The meteorological data for 1908-09 were obtained from records kept by -the Morococha Mining Company for use in a projected hydro-electric -installation. Other data covering the years 1906-11 have appeared in the -bulletins of the <i>Sociedad Geográfica de Lima</i>. These are not complete -but they have supplied rainfall data for the years 1910-11;<a name="FNanchor_36_36" id="FNanchor_36_36"></a><a href="#Footnote_36_36" class="fnanchor">[36]</a> those -for 1906 and 1907 have been obtained from the <i>BoletÃn de Minas</i>.<a name="FNanchor_37_37" id="FNanchor_37_37"></a><a href="#Footnote_37_37" class="fnanchor">[37]</a></p> - -<h4><span class="smcap">Temperature</span></h4> - -<p>The most striking facts expressed by the various temperature curves are -the shortness of the true winter season—its restriction to June and -July—and its abrupt beginning and end. This is well known to anyone who -has lived from April to October or November at high elevations in the -Central Andes. Winter comes on suddenly and with surprising regularity -from year to year during the last few days of May and early June. In the -last week of July or the first week of August the temperatures make an -equally sudden rise. During 1908 and 1909 the mean temperature reached -the freezing point but once each year—July 24 and July 12 -respectively.<a name="page_172" id="page_172"></a> The absolute minimum for the two years was -22° C. July of -1908 and June of 1909 are also the months of smallest diurnal -variability, showing that the winter temperatures are maintained with -great regularity. Like all tropical high-level stations, Morococha -exhibits winter maxima that are very high as compared with the winter -maxima of the temperate zone. In both June and July of 1908 and 1909 the -maximum was maintained for about a week above 55° F. (12.8° C.), and in -1909 above 60° F. (15.6° C.), the mean maximum for the year being only -4.7° F. higher. For equal periods, however, the maxima fell to levels -about 10° F. below those for the period from December to May, 1908.</p> - -<p>It is noteworthy that the lowest maximum for 1909 was in October, 44° F. -(6.7° C.); and that other low maxima but little above those of June and -July occur in almost all the other months of the year. While 1909 was in -this respect an exceptional year, it nevertheless illustrates a fact -that may occur in any month of any year. Its occurrence is generally -associated with cloudiness. One of the best examples of this is found in -the January maximum curve for 1909, where in a few days the maxima fell -12° F. Cloud records are absent, hence a direct comparison cannot be -made, but a comparison of the maximum temperature curve with the graphic -representation of mean monthly rainfall, will emphasize this relation of -temperature and cloudiness. February was the wettest month of both 1908 -and 1909. In sympathy with this is the large and sharp drop from the -January level of the maxima—the highest for the year—to the February -level. The mean temperatures are affected to a less degree because the -cloudiness retards night radiation of heat, thus elevating the maxima. -Thus in 1908 the lowest minimum for both January and February was 28.4° -F. (-2° C.). For 1909 the minima for January and February were 27.5° F. -(-2.5° C.) and 29.3° F. (-1.5° C.) respectively.</p> - -<p><a name="fig_106" id="fig_106"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_172a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_172a_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_172a_sml.jpg" width="399" height="200" alt="" /> -</div> - -<p>The extent to which high minima may hold up the mean temperature is -shown by the fact that the mean monthly temperature for January, 1908, -was lower than for February. Single instances illustrate this relation -equally well. For example, on<a name="page_173" id="page_173"></a><a name="page_174" id="page_174"></a> March 5th, 1908, there occurred the -heaviest rainfall of that year. The maximum and minimum curves almost -touch. The middle of April and late September, 1909, are other -illustrations. The relationship is so striking that I have put the two -curves side by side and have had them drawn to the same scale.</p> - -<table border="1" cellpadding="3" cellspacing="0" summary=""> -<tr><td align="center" colspan="15" -style="border:none;">FREQUENCY OF THE DIURNAL VARIABILITY, MOROCOCHA, 1908 AND 1909</td></tr> -<tr><td align="center" colspan="15" -style="border:none;"> 1908</td></tr> -<tr><td align="center">Degrees F.</td> -<td align="right"> J.</td> -<td align="right"> F.</td> -<td align="right"> M.</td> -<td align="right"> A.</td> -<td align="right"> M.</td> -<td align="right"> J.</td> -<td align="right"> J.</td> -<td align="right"> A.</td> -<td align="right"> S.</td> -<td align="right"> O.</td> -<td align="right"> N.</td> -<td align="right"> D.</td> -<td align="right"></td> -<td align="center">Total No.<br /> of days</td></tr> -<tr><td align="right">0</td> -<td align="right"> —</td> -<td align="right"> 3</td> -<td align="right"> 2</td> -<td align="right"> 3</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> 2</td> -<td align="right"> 1</td> -<td align="right"> 3</td> -<td align="right"> 1</td> -<td align="right"> 1</td> -<td align="right"> 3</td> -<td align="right"></td> -<td align="right"> 19</td></tr> -<tr><td align="right">0-1</td> -<td align="right"> 6</td> -<td align="right"> 5</td> -<td align="right"> 6</td> -<td align="right">10</td> -<td align="right"> 9</td> -<td align="right">10</td> -<td align="right">13</td> -<td align="right">10</td> -<td align="right"> 8</td> -<td align="right"> 6</td> -<td align="right"> 6</td> -<td align="right"> 5</td> -<td align="right"></td> - -<td align="right"> 94</td></tr> -<tr><td align="right">1-2</td> -<td align="right"> 4</td> -<td align="right"> 1</td> -<td align="right"> 3</td> -<td align="right"> 7</td> -<td align="right"> 5</td> -<td align="right"> 3</td> -<td align="right"> 7</td> -<td align="right"> 7</td> -<td align="right"> 8</td> -<td align="right"> 6</td> -<td align="right"> 6</td> -<td align="right"> 4</td> -<td align="right"></td> - -<td align="right"> 61</td></tr> -<tr><td align="right">2-3</td> -<td align="right"> 6</td> -<td align="right"> 1</td> -<td align="right"> 3</td> -<td align="right"> 4</td> -<td align="right"> 9</td> -<td align="right"> 2</td> -<td align="right"> 2</td> -<td align="right"> 4</td> -<td align="right"> 4</td> -<td align="right"> 7</td> -<td align="right"> 7</td> -<td align="right"> 4</td> -<td align="right"></td> - -<td align="right"> 53</td></tr> -<tr><td align="right">3-4</td> -<td align="right"> 5</td> -<td align="right"> 3</td> -<td align="right"> 2</td> -<td align="right"> 3</td> -<td align="right"> 3</td> -<td align="right"> 4</td> -<td align="right"> 2</td> -<td align="right"> 9</td> -<td align="right"> 4</td> -<td align="right"> 5</td> -<td align="right"> 3</td> -<td align="right"> 5</td> -<td align="right"></td> - -<td align="right"> 48</td></tr> -<tr><td align="right">4-5</td> -<td align="right"> 2</td> -<td align="right"> 3</td> -<td align="right"> 1</td> -<td align="right"> 1</td> -<td align="right"> 2</td> -<td align="right"> 5</td> -<td align="right"> 5</td> -<td align="right"> —</td> -<td align="right"> 1</td> -<td align="right"> 1</td> -<td align="right"> 6</td> -<td align="right"> 3</td> -<td align="right"></td> - -<td align="right"> 30</td></tr> -<tr><td align="right">Over 5</td> -<td align="right"> 3</td> -<td align="right"> 4</td> -<td align="right"> 3</td> -<td align="right"> 2</td> -<td align="right"> 3</td> -<td align="right"> 6</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> 2</td> -<td align="right"> 5</td> -<td align="right"> 1</td> -<td align="right"> 5</td> -<td></td> -<td align="right"> 34</td></tr> - -<tr><td align="center">Days per<br /> month</td> -<td align="right">26</td> -<td align="right">20</td> -<td align="right">20</td> -<td align="right">30</td> -<td align="right">31</td> -<td align="right">30</td> -<td align="right">31</td> -<td align="right">31</td> -<td align="right">30</td> -<td align="right">31</td> -<td align="right">30</td> -<td align="right">20</td> -<td align="right"></td> - -<td align="right"> 339</td></tr> -</table> - -<table border="1" cellpadding="3" cellspacing="0" summary=""> -<tr><td align="center" colspan="16" -style="border:none;"> 1909</td></tr> -<tr><td align="right">Degrees F.</td> -<td align="right"> J.</td> -<td align="right"> F.</td> -<td align="right"> M.</td> -<td align="right"> A.</td> -<td align="right"> M.</td> -<td align="right"> J.</td> -<td align="right"> J.</td> -<td align="right"> A.</td> -<td align="right"> S.</td> -<td align="right"> O.</td> -<td align="right"> N.</td> -<td align="right"> D.</td> -<td></td> -<td align="center">Total No.<br /> of days</td> -<td align="center">Mean for<br /> 1908-1909</td></tr> -<tr><td align="right">0</td> -<td align="right"> 6</td> -<td align="right"> 1</td> -<td align="right"> 4</td> -<td align="right"> 2</td> -<td align="right"> 1</td> -<td align="right"> 2</td> -<td align="right"> 4</td> -<td align="right"> 4</td> -<td align="right"> 3</td> -<td align="right"> 6</td> -<td align="right"> 2</td> -<td align="right"> 1</td> -<td></td> -<td align="right"> 36</td> -<td align="right"> 27.5</td></tr> -<tr><td align="right">0-1</td> -<td align="right"> 9</td> -<td align="right"> 8</td> -<td align="right"> 5</td> -<td align="right"> 6</td> -<td align="right"> 6</td> -<td align="right"> 7</td> -<td align="right"> 8</td> -<td align="right">13</td> -<td align="right"> 9</td> -<td align="right"> 4</td> -<td align="right">11</td> -<td align="right">10</td> -<td></td> -<td align="right"> 96</td> -<td align="right"> 95</td></tr> -<tr><td align="right">1-2</td> -<td align="right"> 4</td> -<td align="right"> 6</td> -<td align="right"> 8</td> -<td align="right"> 3</td> -<td align="right">11</td> -<td align="right">14</td> -<td align="right"> 3</td> -<td align="right"> 3</td> -<td align="right"> 5</td> -<td align="right"> 3</td> -<td align="right"> 9</td> -<td align="right"> 6</td> -<td></td> -<td align="right"> 75</td> -<td align="right"> 68</td></tr> -<tr><td align="right">2-3</td> -<td align="right"> 3</td> -<td align="right"> 7</td> -<td align="right"> 4</td> -<td align="right"> 8</td> -<td align="right"> 4</td> -<td align="right"> 3</td> -<td align="right"> 6</td> -<td align="right"> 6</td> -<td align="right"> 4</td> -<td align="right"> 6</td> -<td align="right"> 1</td> -<td align="right"> 3</td> -<td></td> -<td align="right"> 55</td> -<td align="right"> 54</td></tr> -<tr><td align="right">3-4</td> -<td align="right"> 4</td> -<td align="right"> 5</td> -<td align="right"> 3</td> -<td align="right"> 6</td> -<td align="right"> 4</td> -<td align="right"> 4</td> -<td align="right"> 4</td> -<td align="right"> 3</td> -<td align="right"> 6</td> -<td align="right"> 3</td> -<td align="right"> 2</td> -<td align="right"> 5</td> -<td></td> -<td align="right"> 49</td> -<td align="right"> 48.5</td></tr> -<tr><td align="right">4-5</td> -<td align="right"> 1</td> -<td align="right"> 1</td> -<td align="right"> 5</td> -<td align="right"> 1</td> -<td align="right"> 2</td> -<td align="right"> —</td> -<td align="right"> 2</td> -<td align="right"> 1</td> -<td align="right"> 1</td> -<td align="right"> 2</td> -<td align="right"> —</td> -<td align="right"> 2</td> -<td></td> -<td align="right"> 18</td> -<td align="right"> 24</td></tr> -<tr><td align="right">Over 5</td> -<td align="right"> 4</td> -<td align="right"> —</td> -<td align="right"> 2</td> -<td align="right"> 4</td> -<td align="right"> 3</td> -<td align="right"> —</td> -<td align="right"> 4</td> -<td align="right"> 1</td> -<td align="right"> 2</td> -<td align="right"> 7</td> -<td align="right"> 5</td> -<td align="right"> 3</td> -<td></td> -<td align="right"> 35</td> -<td align="right"> 34.5</td></tr> -<tr><td align="center">Days per<br /> month</td> -<td align="right">31</td> -<td align="right">28</td> -<td align="right">31</td> -<td align="right">30</td> -<td align="right">31</td> -<td align="right">30</td> -<td align="right">31</td> -<td align="right">31</td> -<td align="right">30</td> -<td align="right">31</td> -<td align="right">30</td> -<td align="right">30</td> -<td></td> -<td align="right"> 364</td> -<td align="right">351.5</td></tr> -</table> - -<h4>RAINFALL</h4> - -<p>The annual rainfall of Morococha is as follows:</p> - -<table border="0" cellpadding="2" cellspacing="0" summary=""> -<tr><td align="right">1906</td><td align="right">28</td><td align="center">inches</td><td align="right">(</td><td align="right">712 mm.)</td></tr> -<tr><td align="right"><a name="FNanchor_38_38" id="FNanchor_38_38"></a><a href="#Footnote_38_38" class="fnanchor">[38]</a> 1907</td><td align="right">40</td><td align="center">"</td><td align="right">(1,011 mm.)</td></tr> -<tr><td align="right">1908</td><td align="right">57</td><td align="center">"</td><td align="right">(1,450 mm.)</td></tr> -<tr><td align="right">1909</td><td align="right">45</td><td align="center">"</td><td align="right">(1,156 mm.)</td></tr> -<tr><td align="right">1910</td><td align="right">47</td><td align="center">"</td><td align="right">(1,195 mm.)</td></tr> -<tr><td align="right">1911</td><td align="right">25</td><td align="center">"</td><td align="right">(</td><td align="right">622 mm.)</td></tr> -</table> - -<p><a name="fig_107" id="fig_107"></a></p> -<p><a name="fig_107a" id="fig_107a"></a></p> -<p><a name="fig_107b" id="fig_107b"></a></p> -<p><a name="fig_107c" id="fig_107c"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_174_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_174_sml.jpg" width="335" height="192" alt="Fig. 107A." /></a> - -<p class="caption"><span class="smcap">Fig. 107</span>—Rainfall of Morococha. <a href="#fig_107">107</a> A shows daily -rainfall during the rainy (summer) season, 1908-1909. <a href="#fig_107">107</a> B shows -monthly rainfall from July, 1905, to December, 1911, and <a href="#fig_107">107</a> C the -annual and mean rainfall for the same period.</p> -</div> - -<p><a name="page_175" id="page_175"></a></p> - -<p>The mean for the above six years amounts to 40 inches (1,024 mm.). This -is a value considerably higher than that for Caylloma or Santa Lucia. -The greater rainfall of Morococha is probably due in part to its more -northerly situation. An abnormal feature of the rainfall of 1908, the -rainiest year, is the large amount that fell in June. Ordinarily June -and July, the coldest months, are nearly or quite rainless. The normal -concurrence of highest temperatures and greatest precipitation is of -course highly favorable to the plant life of these great altitudes. Full -advantage can be taken of the low summer temperatures if the growing -temperatures are concentrated and are accompanied by abundant rains. -Since low temperatures mean physiologic dryness, whether or not rains -are abundant, the dryness of the winter months has little effect in -restricting the range of Alpine species.</p> - -<p>The seasonal distribution of rain helps the plateau people as well as -the plateau plants. The transportation methods are primitive and the -trails mere tracks that follow the natural lines of topography and -drainage. Coca is widely distributed, likewise corn and barley which -grow at higher elevations, and wool must be carried down to the markets -from high-level pastures. In the season of rains the trails are -excessively wet and slippery, the streams are often in flood and the -rains frequent and prolonged. On the other hand the insignificant -showers of the dry or non-growing season permit the various products to -be exchanged over dry trails.</p> - -<p>The activities of the plateau people have had a seasonal expression from -early times. Inca chronology counted the beginning of the year from the -middle of May, that is when the dry season was well started and it was -inaugurated with the festivals of the Sun. With the exception of June -when the people were entirely busied in the irrigation of their fields, -each month had its appropriate feasts until January, during which month -and February and March no feasts were held. April, the harvest month, -marked the recommencement of ceremonial observances and a revival of -social life.<a name="FNanchor_39_39" id="FNanchor_39_39"></a><a href="#Footnote_39_39" class="fnanchor">[39]</a><a name="page_176" id="page_176"></a></p> - -<p>In Spanish times the ritualistic festivals, incorporated with fairs, -followed the seasonal movement. Today progress in transportation has -caused the decadence of many of the fairs but others still survive. Thus -two of the most famous fairs of the last century, those of Vilque -(province of Puno) and Yunguyo (province of Chucuito), were held at the -end of May and the middle of August respectively. Copacavana, the famous -shrine on the shores of Titicaca, still has a well-attended August fair -and Huari, in the heart of the Bolivian plateau, has an Easter fair -celebrated throughout the Andes.</p> - -<h4><span class="smcap">Cochabamba</span></h4> - -<p>Cochabamba, Bolivia, lies 8,000 feet above sea level in a broad basin in -the Eastern Andes. The Cerro de Tunari, on the northwest, has a snow and -ice cover for part of the year. The tropical forests lie only a single -long day’s journey to the northeast. Yet the basin is dry on account of -an eastern front range that keeps out the rain-bearing trade winds. The -Rio Grande has here cut a deep valley by a roundabout course from the -mountains to the plains so that access to the region is over bordering -elevations. The basin is chiefly of structural origin.</p> - -<p>The weather records from Cochabamba are very important. I could obtain -none but temperature data and they are complete for 1906 only. Data for -1882-85 were secured by von Boeck<a name="FNanchor_40_40" id="FNanchor_40_40"></a><a href="#Footnote_40_40" class="fnanchor">[40]</a> and they have been quoted by -Sievers and Hann. The mean annual temperature for 1906 was 61.9° F. -(16.6° C.), a figure in close agreement with von Boeck’s mean of 60.8° -F. (16° C.). The monthly means indicate a level of temperature favorable -to agriculture. The basin is in fact the most fertile and highly -cultivated area of its kind in Bolivia. Bananas, as well as many other -tropical and subtropical plants, grow in the central plaza. The nights -of midwinter are uncomfortably cool; and the days of midsummer are<a name="page_177" id="page_177"></a><a name="page_178" id="page_178"></a> -uncomfortably hot but otherwise the temperatures are delightful. The -absolute extremes for 1906 were 81.5° F. (27.5° C.) on December 11, and -39.9° F. (4.4° C.) on July 15 and 16. The (uncorrected) readings of von -Boeck give a greater range. High minima rather than high maxima -characterize the summer. The curve for 1906 shows the maxima for June -and July cut off strikingly by an abrupt drop of the temperature and -indicates a rather close restriction of the depth of the season to these -two months, which are also those of greatest diurnal range.</p> - -<p><a name="fig_108" id="fig_108"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_176a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_176a_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_176a_sml.jpg" width="410" height="151" alt="Fig. 108 A—DIURNAL TEMPERATURE, COCHABAMBA, 1906 -B—DIURNAL TEMPERATURE, COCHABARMBA, 1907 -E—DIURNAL RANGE OF TEMPERATURE, COCHABARMBA, 1907 -D—DIURNAL RANGE OF TEMPERATURE, COCHABARMBA, 1906 -G—DIURNAL VARIABILITY, COCHABARMBA, 1906 -H—DIURNAL VARIABILITY, COCHABAMBA, 1907 -C—MEAN MONTHLY TEMPERATURES, COCHABAMBA -F—MONTHLY MEANS OF DIURNAL RANGE, COCHABAMBA" /> -</div> - -<p>The rainfall of about 18 inches is concentrated in the summer season, 85 -per cent falling between November and March. During this time the town -is somewhat isolated by swollen streams and washed out trails: hence -here, as on the plateau, there is a distinct seasonal distribution of -the work of planting, harvesting, moving goods, and even mining, and of -the general commerce of the towns. There is an approach to our winter -season in this respect and in respect of a respite from the almost -continuously high temperatures of summer. The daytime temperatures of -summer are however mitigated by the drainage of cool air from the -surrounding highlands. This, indeed, prolongs the period required for -the maturing of plants, but there are no harmful results because -freezing temperatures are not reached, even in winter.</p> - -<table border="1" cellpadding="3" cellspacing="0" summary=""> -<tr><td align="center" colspan="5" -style="border:none;">MONTHLY TEMPERATURES, COCHABAMBA, 1906</td></tr> -<tr><td align="center">Month</td> -<td align="center"> Mean Min.</td> -<td align="center"> Mean Max.</td> -<td align="center"> Mean Range</td> -<td align="center"> Daily Mean</td></tr> -<tr><td align="left">January</td> -<td align="center"> 55.7</td> -<td align="center"> 72.25</td> -<td align="center"> 16.65</td> -<td align="center"> 63.3</td></tr> -<tr><td align="left">February</td> -<td align="center"> 61.2</td> -<td align="center"> 71.3</td> -<td align="center"> 10.1</td> -<td align="center"> 65.5</td></tr> -<tr><td align="left">March</td> -<td align="center"> 59.8</td> -<td align="center"> 72.6</td> -<td align="center"> 12.8</td> -<td align="center"> 65.5</td></tr> -<tr><td align="left">April</td> -<td align="center"> 55.06</td> -<td align="center"> 70.8</td> -<td align="center"> 15.74</td> -<td align="center"> 62.2</td></tr> -<tr><td align="left">May</td> -<td align="center"> 50.9</td> -<td align="center"> 68.7</td> -<td align="center"> 17.8</td> -<td align="center"> 59.1</td></tr> -<tr><td align="left">June</td> -<td align="center"> 47.1</td> -<td align="center"> 65.6</td> -<td align="center"> 18.5</td> -<td align="center"> 55.6</td></tr> -<tr><td align="left">July</td> -<td align="center"> 44.8</td> -<td align="center"> 64.9</td> -<td align="center"> 20.1</td> -<td align="center"> 54.1</td></tr> -<tr><td align="left">August</td> -<td align="center"> 49.9</td> -<td align="center"> 68.0</td> -<td align="center"> 18.1</td> -<td align="center"> 58.2</td></tr> -<tr><td align="left">September</td> -<td align="center"> 55.6</td> -<td align="center"> 73.2</td> -<td align="center"> 17.6</td> -<td align="center"> 63.7</td></tr> -<tr><td align="left">October</td> -<td align="center"> 56.1</td> -<td align="center"> 73.4</td> -<td align="center"> 17.3</td> -<td align="center"> 64.0</td></tr> -<tr><td align="left">November</td> -<td align="center"> 58.1</td> -<td align="center"> 75.7</td> -<td align="center"> 17.6</td> -<td align="center"> 66.2</td></tr> -<tr><td align="left">December</td> -<td align="center"> 58.6</td> -<td align="center"> 73.9</td> -<td align="center"> 15.3</td> -<td align="center"> 65.8</td></tr> -</table> - -<p><a name="fig_109" id="fig_109"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_178_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_178_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_178_sml.jpg" width="335" height="190" alt="Figs. 109-113—Temperature curves for locations in the -montaña, July and August, 1911. The curves are based on hourly readings -with interpolated readings for such critical occurrences as the -appearance of cloud or rain. Dry bulb readings are shown by solid lines, -wet bulb by dotted lines, and breaks in the continuity of the -observations by heavy broken lines. Fig. 109 is for Pongo de Mainique, -August 20 and 21; Fig. 110 for Yavero; Fig. 111 for Santo Anato, August -11 and 12; Fig. 112 for Sahuayaco, August 20, and Fig. 113 for Santa -Ana, July 30 to August 1." /> -<br /> -<p class="caption"><span class="smcap">Fig</span>s. 109-113—Temperature curves for locations in the -montaña, July and August, 1911. The curves are based on hourly readings -with interpolated readings for such critical occurrences as the -appearance of cloud or rain. Dry bulb readings are shown by solid lines, -wet bulb by dotted lines, and breaks in the continuity of the -observations by heavy broken lines. <a href="#fig_109">109</a> is for Pongo de Mainique, -August 20 and 21; Fig. 110 for Yavero; Fig. 111 for Santo Anato, August -11 and 12; Fig. 112 for Sahuayaco, August 20, and Fig. 113 for Santa -Ana, July 30 to August 1.</p> -</div> - -<p><a name="fig_114" id="fig_114"></a></p> - -<p><a name="fig_115" id="fig_115"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_178a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_178a_sml.jpg" width="210" height="324" alt="Fig. 114—Typical afternoon cloud composition at Santa -Ana during the dry season." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 114—Typical afternoon cloud composition at Santa -Ana during the dry season.</p> - -<p class="caption"><span class="smcap">Fig. 115</span>—Temperature curve for Abancay drawn from data -obtained by hourly readings on September 27, 1911. Dry bulb readings are -shown by a heavy solid line, wet bulb readings by a dotted line. The -heavy broken line shows the normal curve when the sky is unobscured by -cloud. The reduction in temperature with cloud is very marked.</p> -</div> - -<table border="1" cellpadding="3" cellspacing="0" summary=""> -<tr><td align="center" -colspan="14" style="border:none;">FREQUENCY OF DIURNAL VARIABILITY AT COCHABAMBA, 1906</td></tr> -<tr><td align="center">Degrees F.</td> -<td align="center"> J.</td> -<td align="center"> F.</td> -<td align="center"> M.</td> -<td align="center"> A.</td> -<td align="center"> M.</td> -<td align="center"> J.</td> -<td align="center"> J.</td> -<td align="center"> A.</td> -<td align="center"> S.</td> -<td align="center"> O.</td> -<td align="center"> N.</td> -<td align="center"> D.</td> -<td align="right"></td> -<td align="center">Total No. of<br /> days</td></tr> -<tr><td align="right">0</td> -<td align="right"> 1</td> -<td align="right"> 3</td> -<td align="right"> 10</td> -<td align="right"> 12</td> -<td align="right"> 6</td> -<td align="right"> 10</td> -<td align="right"> 9</td> -<td align="right"> 6</td> -<td align="right"> 9</td> -<td align="right"> 6</td> -<td align="right"> 3</td> -<td align="right"> 4</td> -<td align="right"></td> -<td align="right"> 79</td></tr> -<tr><td align="right">0-1</td> -<td align="right"> 5</td> -<td align="right"> —</td> -<td align="right"> 3</td> -<td align="right"> 5</td> -<td align="right"> 3</td> -<td align="right"> 3</td> -<td align="right"> —</td> -<td align="right"> 4</td> -<td align="right"> —</td> -<td align="right"> 3</td> -<td align="right"> 1</td> -<td align="right"> 1</td> -<td align="right"></td> -<td align="right"> 28</td></tr> -<tr><td align="right">1-2</td> -<td align="right"> 10</td> -<td align="right"> 10</td> -<td align="right"> 13</td> -<td align="right"> 11</td> -<td align="right"> 15</td> -<td align="right"> 7</td> -<td align="right"> 14</td> -<td align="right"> 11</td> -<td align="right"> 15</td> -<td align="right"> 10</td> -<td align="right"> 14</td> -<td align="right"> 13</td> -<td align="right"></td> -<td align="right"> 143</td></tr> -<tr><td align="right">2-3</td> -<td align="right"> 7</td> -<td align="right"> 11</td> -<td align="right"> 3</td> -<td align="right"> 1</td> -<td align="right"> 5</td> -<td align="right"> 8</td> -<td align="right"> 7</td> -<td align="right"> 4</td> -<td align="right"> 3</td> -<td align="right"> 6</td> -<td align="right"> 7</td> -<td align="right"> 6</td> -<td align="right"></td> -<td align="right"> 68</td></tr> -<tr><td align="right">3-4</td> -<td align="right"> 6</td> -<td align="right"> 2</td> -<td align="right"> 2</td> -<td align="right"> 1</td> -<td align="right"> 2</td> -<td align="right"> 2</td> -<td align="right"> 1</td> -<td align="right"> 6</td> -<td align="right"> 3</td> -<td align="right"> 4</td> -<td align="right"> 3</td> -<td align="right"> 5</td> -<td align="right"></td> -<td align="right"> 37</td></tr> -<tr><td align="right">4-5</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> 1</td> -<td align="right"> 1</td> -<td align="right"> 1</td> -<td align="right"></td> -<td align="right"> 3</td></tr> -<tr><td align="right">Over 5</td> -<td align="right"> 2</td> -<td align="right"> 2</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> —</td> -<td align="right"> 1</td> -<td align="right"> 1</td> -<td align="right"> 1</td> -<td align="right"></td> -<td align="right"> 7</td></tr> -</table> - -<p><a name="page_179" id="page_179"></a></p> - -<p>A series of curves shows the daily march of temperature at various -locations along the seventy-third meridian. Figs. 109 to 113 are for the -Urubamba Valley. Respectively they relate to Pongo de Mainique, 1,200 -feet elevation (365 m.), the gateway to the eastern plains; Yavero, -1,600 feet (488 m.), where the tributary of this name enters the main -stream; Santo Anato, 1,900 feet (580 m.); Sahuayaco, 2,400 feet (731 -m.), and Santa Ana, 3,400 feet (1,036 m.), one of the outposts of -civilization beyond the Eastern Cordillera. The meteorological -conditions shown are all on the same order. They are typical of dry -season weather on the dry floor of a montaña valley. The smooth curves -of clear days are marked by high mid-day temperatures and great diurnal -range. Santo Anato is a particularly good illustration: the range for -the 24 hours is 38° F. (21.1° C.). This site, too, is remarkable as one -of the most unhealthful of the entire valley. The walls of the valley -here make a sharp turn and free ventilation of the valley is obstructed. -During the wet season tertian fever prevails to a degree little known -east of the Cordillera, though notorious enough in the deep valleys of -the plateau. The curves show relative humidity falling to a very low -minimum on clear days. At Santo Anato and Santa Ana, for example, it -drops below 30 per cent during the heat of the day. Afternoon -cloudiness, however, is a common feature even of the dry season. A -typical afternoon cloud formation is shown in <a href="#fig_114">114</a> . The effect on -temperature is most marked. It is well shown in the curve for August 20 -and 22 at Yavero. Cloudiness and precipitation<a name="page_180" id="page_180"></a> increase during the -summer months. At Santa Ana the rainfall for the year 1894-95 amounted -to 50 inches, of which 60 per cent fell between December and March. For -a discussion of<a name="page_181" id="page_181"></a> topographic features that have some highly interesting -climatic effects in the eastern valleys of Peru see Chapter VI.</p> - -<p><a name="fig_116" id="fig_116"></a></p> -<p><a name="fig_117" id="fig_117"></a></p> -<p><a name="fig_118" id="fig_118"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_180_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_180_sml.jpg" width="206" height="267" alt="Figs. 116-118—Temperature curves for locations in the -Maritime Cordillera and its western valleys, October, 1911. For -construction of curves see Figs. 109-113. Fig. 116 is for Camp 13 on the -northern slope of the Maritime Cordillera (which here runs from east to -west), October 13-15; Fig. 117 for Cotahuasi, October 26; Fig. 118 for -Salamanca, October 31." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>s. 116-118—Temperature curves for locations in the -Maritime Cordillera and its western valleys, October, 1911. For -construction of curves see Figs. 109-113. <a href="#fig_116">116</a> is for Camp 13 on the -northern slope of the Maritime Cordillera (which here runs from east to -west), October 13-15; <a href="#fig_117">117</a> for Cotahuasi, October 26; <a href="#fig_118">118</a> for -Salamanca, October 31.</p> -</div> - -<div class="figcenter"> -<a href="images/ill_page_181_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_181_sml.jpg" width="210" height="86" alt="Fig. 119. - -Fig. 120. - -Figs. 119-120—Temperature curves for the Coast Desert, November, 1911. -Fig. 119 is for Aplao, November 4 and 5; and Fig. 120 for Camaná, -November 9 and 10. For construction of curves see Figs. 109 to 113." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 119. -Fig. 120. -Figs. 119-120—Temperature curves for the Coast Desert, November, 1911. -Fig. 119 is for Aplao, November 4 and 5; and Fig. 120 for Camaná, -November 9 and 10. For construction of curves see <a href="#fig_109">Figs. 109 to 113</a>.</p> -</div> - -<p>Abancay, 8,000 feet (2,440 m.), in one of the inter-Andean basins, is -situated in the zone of marked seasonal precipitation. The single day’s -record shows the characteristic effect of cloud reducing the maximum -temperature of the day and maintaining the relative humidity.</p> - -<p>Camp 13, 15,400 feet (4,720 m.), lies near the crest of the Maritime -Cordillera a little south of Antabamba. Afternoon storms are one of its -most significant features. Cotahuasi, 9,100 feet (2,775 m.) is near the -head of a west-coast valley. Its low humidity is worthy of note. That -for Salamanca, 12,700 feet (3,870 m.), is similar but not so marked.</p> - -<p>Aplao, 3,100 feet (945 m.), and Camaná at the seacoast are stations in -the west-coast desert. The interior location of the former gives it a -greater range of temperature than Camaná, yet even here the range is -small in comparison with the diurnal extremes of the montaña, and the -tempering effect of the sea-breeze is clearly apparent. Camaná shows a -diurnal temperature range of under 10° F. and also the high relative -humidity, over 70 per cent, characteristic of the coast.<a name="page_182" id="page_182"></a><a name="page_183" id="page_183"></a></p> - -<h2><a name="PART_II" id="PART_II"></a>PART II<br /><br /> -PHYSIOGRAPHY OF THE PERUVIAN ANDES</h2> - -<h3><a name="CHAPTER_XI" id="CHAPTER_XI"></a>CHAPTER XI<br /><br /> -THE PERUVIAN LANDSCAPE</h3> - -<p>F<small>ROM</small> the west coast the great Andean Cordillera appears to have little -of the regularity suggested by our relief maps. Steep and high cliffs in -many places form the border of the land and obstruct the view; beyond -them appear distant summits rising into the zone of clouds. Where the -cliffs are absent or low, one may look across a sun-baked, yellow -landscape, generally broken by irregular foothills that in turn merge -into the massive outer spurs and ranges of the mountain zone. The plain -is interrupted by widely separated valleys whose green lowland meadows -form a brilliant contrast to the monotonous browns and yellows of the -shimmering desert. In rare situations the valley trenches enable one to -look far into the Cordillera and to catch memorable glimpses of lofty -peaks capped with snow.</p> - -<p>If the traveler come to the west-coast landscape from the well-molded -English hills or the subdued mountains of Vermont and New Hampshire with -their artistic blending of moderate profiles, he will at first see -nothing but disorder. The scenery will be impressive and, in places, -extraordinary, but it is apparently composed of elements of the greatest -diversity. All the conceivable variations of form and color are -expressed, with a predominance of bold rugged aspects that give a -majestic appearance to the mountain-bordered shore. One looks in vain -for some sign of a quiet view, for some uniformity of features, for some -landscape that will remind him of the familiar hills of home. The Andes -are aggressive mountains that front the sea in formidable spurs or -desert ranges. Could we see in one view their entire elevation<a name="page_184" id="page_184"></a> from -depths of over 20,000 feet beneath sea level to snowy summits, a total -altitude of 40,000 feet (12,200 m.), their excessive boldness would be -more apparent. No other mountains in the world are at once so -continuously lofty and so near a coast which drops off to abyssal -depths.</p> - -<p>The view from the shore is, however, but one of many which the Andes -exhibit. Seen from the base the towering ranges display a stern aspect, -but, like all mountains, their highest slopes and spurs must be crossed -and re-crossed before the student is aware of other aspects of a quite -different nature. The Andes must be observed from at least three -situations: from the floors of the deep intermontane valleys, from the -intermediate slopes and summits, and from the uppermost levels as along -the range crests and the highest passes. Strangely enough it is in the -summit views that one sees the softest forms. At elevations of 14,000 to -16,000 feet (4,270 to 4,880 m.), where one would expect rugged spurs, -serrate chains, and sharp needles and horns, one comes frequently upon -slopes as well graded as those of a city park—grass-covered, -waste-cloaked, and with gentle declivity (Figs. 121-124).</p> - -<p>The graded, waste-cloaked slopes of the higher levels are interpreted as -the result of prolonged denudation in an erosion cycle which persisted -through the greater part of the Tertiary period, and which was closed by -uplifts aggregating at least several thousands of feet. Above the level -of the mature slopes rise the ragged profiles and steep, naked -declivities of the snow-capped mountains which bear residual relations -to the softer forms at their bases. They are formed upon rock masses of -greater original elevation and of higher resistance to denudation. -Though they are dominating topographic features, they are much less -extensive and significant than the tame landscape which they surmount.</p> - -<p><a name="fig_121" id="fig_121"></a></p> - -<p><a name="fig_122" id="fig_122"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_184a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_184a_sml.jpg" width="219" height="326" alt="Fig. 121—Looking north from the hill near Anta in the -Anta basin north of Cuzco. Typical composition of slopes and intermont -basins in the Central Andes. Alluvial fill in the foreground; mature -slopes in the background; in the extreme background the snow-capped -crests of the Cordillera Vilcapampa." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 121—Looking north from the hill near Anta in the -Anta basin north of Cuzco. Typical composition of slopes and intermont -basins in the Central Andes. Alluvial fill in the foreground; mature -slopes in the background; in the extreme background the snow-capped -crests of the Cordillera Vilcapampa.</p> - -<p class="caption"><span class="smcap">Fig. 122</span>—Showing topographic conditions before the -formation of the deep canyons in the Maritime Cordillera. The view, -looking across a tributary canyon of the Antabamba river, shows in the -background the main canyon above Huadquirca. Compare with <a href="#fig_60">Fig. 60</a>.</p> -</div> - -<p>Below the level of the mature slopes are topographic features of equal -prominence: gorges and canyons up to 7,000 feet deep. The deeply -intrenched streams are broken by waterfalls and almost continuous -rapids, the valley walls are so abrupt that one may, in places, roll -stones down a 4,000 foot incline to the river<a name="page_185" id="page_185"></a> bed, and the tortuous -trail now follows a stream in the depths of a profound abyss, now scales -the walls of a labyrinthine canyon.</p> - -<p><a name="fig_123" id="fig_123"></a></p> - -<p><a name="fig_124" id="fig_124"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_184b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_184b_sml.jpg" width="314" height="213" alt="Fig. 123—Mature slopes between Ollantaytambo and -Urubamba." /></a> -<br /> - -<table border="0" cellpadding="5" cellspacing="0" summary=""> -<tr valign="top"><td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 123—Mature slopes between Ollantaytambo and -Urubamba.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig. 124</span>—Dissected mature slopes north of Anta in the -Anta basin north of Cuzco.</p></td></tr></table> -</div> - -<p><a name="fig_125" id="fig_125"></a></p> - -<div class="figright" style="width: 116px;"> -<a href="images/ill_page_185_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_185_sml.jpg" width="116" height="63" alt="Fig. 125—Mature upper and young lower slopes at the -outlet of the Cuzco basin." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 125—Mature upper and young lower slopes at the -outlet of the Cuzco basin.</p> -</div> - -<p>The most striking elements of scenery are not commonly the most -important in physiography. The oldest and most significant surface may -be at the top of the country, where it is not seen by the traveler or -where it cannot impress him, except in contrast to features of greater -height or color. The layman frequently seizes on a piece of bad-land -erosion or an outcrop of bright-colored sandstone or a cliff of -variegated clays or a snow-covered mountain as of most interest. All we -can see of a beautiful snow-clad peak is mere entertainment compared -with what subdued waste-cloaked hill-slopes may show. We do not wish to -imply that everywhere the tops of the Andes are meadows, that there are -no great scenic features in the Peruvian mountains, or that they are not -worth while. But we do wish to say that the bold features are far less -important in the interpretation of the landscape.</p> - -<p>Amid all the variable forms of the Peruvian Cordillera certain strongly -developed types recur persistently. That their importance and relation -may be appreciated we shall at once name them categorically and -represent them in the form of a block diagram (<a href="#fig_126">Fig. 126</a>). The principal -topographic types are as follows:</p> - -<div class="blockquot"><p>1. An extensive system of high-level, well-graded, mature slopes, -below which are:</p> - -<p>2. Deep canyons with steep, and in places, cliffed sides and narrow -floors, and above which are:</p> - -<p>3. Lofty residual mountains composed of resistant, highly deformed -rock, now sculptured into a maze of serrate ridges and sharp -commanding peaks.</p> - -<p>4. Among the forms of high importance, yet causally unrelated to -the other closely associated types, are the volcanic cones and -plateaus of the western Cordillera.<a name="page_186" id="page_186"></a></p> - -<p>5. At the valley heads are a full complement of glacial features, -such as cirques, hanging valleys, reversed slopes, terminal -moraines, and valley trains.</p> - -<p>6. Finally there is in all the valley bottoms a deep alluvial fill -formed during the glacial period and now in process of dissection.</p></div> - -<p>Though there are in many places special features either remotely related -or quite unrelated to the principal enumerated types, they belong to the -class of minor forms to which relatively small attention will be paid, -since they are in general of small extent and of purely local interest.</p> - -<p><a name="fig_126" id="fig_126"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_186_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_186_sml.jpg" width="220" height="111" alt="Fig. 126—Block diagram of the typical physiographic -features of the Peruvian Andes." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 126—Block diagram of the typical physiographic -features of the Peruvian Andes.</p> -</div> - -<p>The block diagram represents all of these features, though of necessity -somewhat more closely associated than they occur in nature. Reference to -the photographs, Figs. 121-124, will make it clear that the diagram is -somewhat ideal: on the other hand the photographs together include all -the features which the diagram displays. In descending from any of the -higher passes to the valley floor one passes in succession down a steep, -well-like cirque at a glaciated valley head, across a rocky terminal -moraine, then down a stair-like trail cut into the steep scarps which -everywhere mark the descent to the main valley floors, over one after -another of the confluent alluvial fans that together constitute a large -part of the valley fill, and finally down the steep sides of the inner -valley to the boulder-strewn bed of the ungraded river.<a name="page_187" id="page_187"></a></p> - -<p>We shall now turn to each group of features for description and -explanation, selecting for first consideration the forms of widest -development and greatest significance—the high-level mature slopes -lying between the lofty mountains which rise above them and the deep, -steep-walled valleys sunk far below them. These are the great pasture -lands of the Cordillera; their higher portions constitute the typical -<i>puna</i> of the Indian shepherds. In many sections it is possible to -pasture the vagrant flocks almost anywhere upon the graded slopes, -confident that the <i>ichu</i>, a tufted forage grass, will not fail and that -scattered brooks and springs will supply the necessary water. At -nightfall the flocks are driven down between the sheltering walls of a -canyon or in the lee of a cliff near the base of a mountain, or, failing -to reach either of these camps, the shepherd confines his charge within -the stone walls of an isolated corral.</p> - -<p>In those places where the graded soil-covered slopes lie within the zone -of agriculture—below 14,000 feet—they are cultivated, and if the soil -be deep and fertile they are very intensively cultivated. Between Anta -and Urubamba, a day’s march north of Cuzco, the hill slopes are covered -with wheat and barley fields which extend right up to the summits (Fig. -134). In contrast are the uncultivated soil-less slopes of the mountains -and the bare valley walls of the deeply intrenched streams. The -distribution of the fields thus brings out strongly the principal -topographic relations. Where the softer slopes are at too high a level, -the climatic conditions are extreme and man is confined to the valley -floors and lower slopes where a laborious system of terracing is the -first requirement of agriculture.</p> - -<p>The appearance of the country after the mature slopes had been formed is -brought out in <a href="#fig_122">122</a> . The camera is placed on the floor of a still -undissected, mature valley which shows in the foreground of the -photograph. In the middle distance is a valley whose great depth and -steepness are purposely hidden; beyond the valley are the smoothly -graded, catenary curves, and interlocking spurs of the mature upland. In -imagination one sees the valleys filled and the valley slopes confluent -on the former (now<a name="page_188" id="page_188"></a> imaginary) valley floor which extends without -important change of expression to the border of the Cordillera. No -extensive cliffs occur on the restored surface, and none now occur on -large tracts of the still undissected upland. Since the mature slopes -represent a long period of weathering and erosion, their surfaces were -covered with a deep layer of soil. Where glaciation at the higher levels -and vigorous erosion along the canyons have taken place, the former soil -cover has been removed; elsewhere it is an important feature. Its -presence lends a marked softness and beauty to these lofty though -subdued landscapes.</p> - -<p>The graded mountain slopes were not all developed (1) at the same -elevation, nor (2) upon rock of the same resistance to denudation, nor -(3) at the same distance from the major streams, nor (4) upon rock of -the same structure. It follows that they will not all display precisely -the same form. Upon the softer rocks at the lowest levels near the -largest streams the surface was worn down to extremely moderate slopes -with a local relief of not more than several hundred feet. Conversely, -there are quite unreduced portions whose irregularities have mountainous -proportions, and between these extremes are almost all possible -variations. Though the term <i>mature</i> in a broad way expresses the stage -of development which the land had reached, <i>post mature</i> should be -applied to those portions which suffered the maximum reduction and now -exhibit the softest profiles. At no place along the 73rd meridian was -denudation carried to the point of even local peneplanation. All of the -major and some of the minor divides bear residual elevations and even -approximately plane surfaces do not exist.</p> - -<div class="figcenter"> -<a href="images/ill_page_188a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_188a_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_188a_sml.jpg" width="370" height="426" alt="THE YALE PERUVIAN EXPEDITION OF 1911 -HIRAM BINGHAM, DIRECTOR -COROPUNA QUADRANGLE -(Cotahuasi)" /> -</div> - -<p>Among the most important features of the mature slopes are (1) their -great areal extent—they are exhibited throughout the whole Central -Andes, (2) their persistent development upon rocks of whatever structure -or degree of hardness, and (3) their present great elevation in spite of -moderate grades indicative of their development at a much lower -altitude. Mature slopes of equivalent form are developed in widely -separated localities in the Central Andes: in every valley about -Cochabamba, Bolivia, at 10,000 feet (3,050 m.); at Crucero Alto in -southern Peru at 14,600 feet<a name="page_189" id="page_189"></a> (4,450 m.); several hundred miles farther -north at Anta near Cuzco, 11,000 feet to 12,000 feet (3,600 to 3,940 -m.), and <a href="#fig_129">129</a> shows typical conditions in the Vilcabamba Valley -along the route of the Yale Peruvian Expedition of 1911. The -characteristic slopes so clearly represented in these four photographs -are the most persistent topographic elements in the physiography of the -Central Andes.</p> - -<p><a name="fig_127" id="fig_127"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_189_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_189_sml.jpg" width="211" height="194" alt="Fig. 127—Topographic profiles across typical valleys of -southern Peru. They are drawn to scale and the equality of gradient of -the gentler upper slopes is so close that almost any curve would serve -as a composite of the whole. These curves form the basis of the diagram, -Fig. 128, whereby the amount of elevation of the Andes in late geologic -time may be determined. The approximate locations of the profiles are as -follows: 1, Antabamba; 2, Chuquibambilla; 3, upland south of Antabamba; -4, Apurimac Canyon above Pasaje; 5, Abancay; 6, Arma (Cordillera -Vilcapampa); 7, divide above Huancarama; 8, Huascatay; 9, Huasentay, -farther downstream; 10, Rio Pampas. The upper valley in 8 is still -undissected; 7 is practically the same; 8a is at the level which 8 must -reach before its side slopes are as gentle as at the end of the -preceding interrupted cycle." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 127—Topographic profiles across typical valleys of -southern Peru. They are drawn to scale and the equality of gradient of -the gentler upper slopes is so close that almost any curve would serve -as a composite of the whole. These curves form the basis of the diagram, -Fig. 128, whereby the amount of elevation of the Andes in late geologic -time may be determined. The approximate locations of the profiles are as -follows: 1, Antabamba; 2, Chuquibambilla; 3, upland south of Antabamba; -4, Apurimac Canyon above Pasaje; 5, Abancay; 6, Arma (Cordillera -Vilcapampa); 7, divide above Huancarama; 8, Huascatay; 9, Huasentay, -farther downstream; 10, Rio Pampas. The upper valley in 8 is still -undissected; 7 is practically the same; 8a is at the level which 8 must -reach before its side slopes are as gentle as at the end of the -preceding interrupted cycle.</p> -</div> - -<p><a name="page_190" id="page_190"></a></p> - -<p>The rock masses upon which the mature slopes were formed range from soft -to hard, from stratified shales, slates, sandstones, conglomerates, and -limestones to volcanics and intrusive granites. While these variations -impose corresponding differences of form, the graded quality of the -slopes is rarely absent. In some places the highly inclined strata are -shown thinly veiled with surface débris, yet so even as to appear -artificially graded. The rock in one place is hard granite, in another a -moderately hard series of lava flows, and again rather weak shales and -sandstones.</p> - -<p>Proof of the rapid and great uplift of certain now lofty mountain ranges -in late geologic time is one of the largest contributions of -physiography to geologic history. Its validity now rests upon a large -body of diversified evidence. In 1907 I crossed the Cordillera Sillilica -of Bolivia and northern Chile and came upon clear evidences of recent -and great uplift. The conclusions presented at that time were tested in -the region studied in 1911, 500 miles farther north, with the result -that it is now possible to state more precisely the dates of origin of -certain prominent topographic forms, and to reconstruct the conditions -which existed before the last great uplift in which the Central Andes -were born. The relation to this general problem of the forms under -discussion will now be considered.</p> - -<p>The gradients of the mature slopes, as we have already seen, are -distinctly moderate. In the Anta region, over an area several hundred -square miles in extent, they run from several degrees to 20° or 30°. -Ten-degree slopes are perhaps most common. If the now dissected slopes -be reconstructed on the basis of many clinometer readings, photographs, -and topographic maps, the result is a series of profiles as in <a href="#fig_127">127</a> . -If, further, the restored slopes be coördinated over an extensive area -the gradients of the resulting valley floors will run from 3° to 10°. -Finally, if these valley floors be extended westward to the Pacific and -eastward to the Amazon basin, they will be found about 5,000 feet above -sea level and 4,000 feet above the eastern plains. (For explanation of -method and data employed, see the accompanying figures 127-128). It is, -therefore, a justifiable conclusion that since the<a name="page_191" id="page_191"></a><a name="page_192" id="page_192"></a> formation of the -slopes the Andes have been uplifted at least a mile, or, to put it in -another way, the Andes at the time of formation of the mature slopes -were at least a mile lower than they are at present.</p> - -<p><a name="fig_128" id="fig_128"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_191_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_191_sml.jpg" width="329" height="143" alt="Fig. 128—Composition of slopes and profiles in the -Peruvian Andes. By superimposing the cross profiles of typical valleys -as shown in Fig. 127 a restoration is possible of the longitudinal -profiles of the earlier cycle of erosion. The difference in elevation of -the two profiles gives less than the minimum amount of uplift that must -have occurred. Case A represents a valley in which recent cutting has -not yet reached the valley head. Below the point 1 the profile has been -steepened and lowered by erosion in the current cycle. Above point 1 the -profile is still in the stage it reached in the preceding cycle. In case -B the renewed erosion of the current cycle has reached to the valley -head. Case C represents conditions similar to those in the preceding -cases save that the stream is typical of those that lie nearest the -steep flexed or faulted margins of the Cordillera and discharge to the -low levels of the desert pampa on the west or the tropical plains on the -east." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 128—Composition of slopes and profiles in the -Peruvian Andes. By superimposing the cross profiles of typical valleys -as shown in <a href="#fig_127">127</a> a restoration is possible of the longitudinal -profiles of the earlier cycle of erosion. The difference in elevation of -the two profiles gives less than the minimum amount of uplift that must -have occurred. Case A represents a valley in which recent cutting has -not yet reached the valley head. Below the point 1 the profile has been -steepened and lowered by erosion in the current cycle. Above point 1 the -profile is still in the stage it reached in the preceding cycle. In case -B the renewed erosion of the current cycle has reached to the valley -head. Case C represents conditions similar to those in the preceding -cases save that the stream is typical of those that lie nearest the -steep flexed or faulted margins of the Cordillera and discharge to the -low levels of the desert pampa on the west or the tropical plains on the -east.</p> -</div> - -<p>Further proof of recent and great uplift is afforded by the deeply -intrenched streams. After descending the long graded slopes one comes -upon the cliffed canyons with a feeling of consternation. The effect of -powerful erosion, incident upon uplift, is heightened by the ungraded -character of the river bed. Falls and rapids abound, the river profiles -suggest tumultuous descents, and much time will elapse before the river -beds have the regular and moderate gradients of the streams draining the -mature surface before uplift as shown in the profiles by the dotted -lines representing the restored valley floors of the older cycle. Since -the smooth-contoured landscape was formed great changes have taken -place. The streams have changed from completely graded to almost -completely ungraded profiles; in place of a subdued landscape we now -have upland slopes intersected by mile-deep canyons; the high-level -slopes could not have been formed under existing conditions, for they -are being dissected by the present streams.</p> - -<div class="figcenter"> -<a href="images/ill_page_192a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_192a_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_192a_sml.jpg" width="378" height="423" alt="THE YALE PERUVIAN EXPEDITION OF 1911 -HIRAM BINGHAM, DIRECTOR -COTAHUASI QUADRANGLE -(La Cumbre)" /> -</div> - -<p>Since the slopes of the land in general undergo progressive changes in -the direction of flatter gradients during a given geographical cycle, it -follows that with the termination of one cycle and the beginning of -another, two sets of slopes will exist and that the gradients of the two -will be unlike. The result is a break in the descent of the slopes from -high to low levels to which the name “topographic unconformity†is now -applied. It will be a prominent feature of the landscape if the higher, -older, and flatter gradients have but little declivity, and the -gradients of the lower younger slopes are very steep. In those places -where the relief of the first cycle was still great at the time of -uplift, the erosion forms of the second cycle may not be differentiated -from those of the first, since both are marked by steep gradients. In -the Central Andes the change in gradient between the higher and lower -slopes is generally well marked. It occurs at variable heights<a name="page_193" id="page_193"></a> above -the valley floors, though rarely more than 3,000 feet above them. In the -more central tracts, far from the main streams and their associated -canyons, dissection in the present erosion cycle has not yet been -initiated, the mature slopes are still intact, and a topographic -unconformity has not yet been developed. The higher slopes are faced -with rock and topped with slowly moving waste. Ascent of the spur end is -by steep zigzag trails; once the top is gained the trail runs along the -gentler slopes without special difficulties.</p> - -<p>It is worth noting at this point that the surface of erosion still older -than the mature slopes herewith described appears not to have been -developed along the seventy-third meridian of Peru, or if developed at -one time, fragments of it no longer remain. The last well-developed -remnant is southwest of Cuzco, <a href="#fig_130">130</a> . I have elsewhere described the -character and geographic distribution of this oldest recognizable -surface of the Central Andes.<a name="FNanchor_41_41" id="FNanchor_41_41"></a><a href="#Footnote_41_41" class="fnanchor">[41]</a> Southern Peru and Bolivia and northern -Chile display its features in what seems an unmistakable manner. The -best locality yet found is in the Desaguadero Valley between Ancoaqui -and Concordia. There one may see thousands of feet of strongly inclined -sediments of varying resistance beveled by a well-developed surface of -erosion whose preserval is owing to a moderate rainfall and to location -in an interior basin.<a name="FNanchor_42_42" id="FNanchor_42_42"></a><a href="#Footnote_42_42" class="fnanchor">[42]</a></p> - -<p>The highest surface of a region, if formed during a prolonged period of -erosion, becomes a surface of reference in the determination of the -character and amount of later crustal deformations, having somewhat the -same functions as a key bed in stratigraphic geology. Indeed, concrete -physiographic facts may be the <i>only</i> basis for arguments as to both -epeirogenic and orogenic movements. The following considerations may -show in condensed form the relative value of physiographic evidence:</p> - -<p><a name="page_194" id="page_194"></a>1. If movements in the earth’s crust are predominantly <i>downward</i>, -sedimentation may be carried on continuously, and a clear geologic -record may be made.</p> - -<p>2. Even if crustal movements are alternately downward and upward, -satisfactory conclusions may be drawn from both (a) the nature of the -buried surfaces of erosion, and (b) the alternating character of the -sediments.</p> - -<p>3. If, however, the deformative processes effect steady or intermittent -uplifts, there may be no sediments, at least within the limits of the -positive crustal units, and a geologic record must be derived not from -sedimentary deposits but from topographic forms. We speak of the <i>lost -intervals</i> represented by stratigraphic breaks or unconformities and -commonly emphasize our ignorance concerning them. The longest, and, from -the human standpoint, the most important, break in the sedimentary -record is that of the present wherever degradation is the predominant -physiographic process. Unlike the others the <i>lost interval</i> of the -present is not lost, if we may so put it, but is in our possession, and -may be definitely described as a concrete thing. It is the physiography -of today.</p> - -<p>Even where long-buried surfaces of erosion are exposed to view, as in -northern Wisconsin, where the Pre-Cambrian paleo-plain projects from -beneath the Paleozoic sediments, or, as in New Jersey and southeastern -Pennsylvania, where the surface developed on the crystalline rocks -became by depression the floor of the Triassic and by more recent uplift -and erosion has been exposed to view,—even in such cases the exposures -are of small extent and give us at best but meager records. In short, -many of the breaks in the geologic record are of such long duration as -to make imperative the use of physiographic principles and methods. The -great Appalachian System of eastern North America has been a land area -practically since the end of the Paleozoic. In the Central Andes the -“lost interval,†from the standpoint of the sedimentary, record, dates -from the close of the Cretaceous, except in a few local intermont basins -partially filled with Tertiary or Pleistocene deposits. Physiographic -interpretations, therefore, serve the double purpose of supplying a part -of the geologic record<a name="page_195" id="page_195"></a> while at the same time forming a basis for the -scientific study of the surface distribution of living forms.</p> - -<p>The geologic dates of origin of the principal topographic forms of the -Central Andes may be determined with a fair degree of accuracy. Geologic -studies in Peru and Bolivia have emphasized the wide distribution of the -Cretaceous formations. They consist principally of thick limestones -above and sandstones and conglomerates below, and thus represent -extensive marine submergence of the earth’s crust in the Cretaceous -where now there are very lofty mountains. The Cretaceous deposits are -everywhere strongly deformed or uplifted to a great height, and all have -been deeply eroded. They were involved, together with other and much -older sediments, in the erosion cycle which resulted in the development -of the widely extended series of mature slopes already described. From -low scattered island elevations projecting above sea level, as in the -Cretaceous period, the Andes were transformed by compression and uplift -to a rugged mountain belt subjected to deep and powerful erosion. The -products of erosion were in part swept into the adjacent seas, in part -accumulated on the floors of intermont basins, as in the great interior -basins of Titicaca and Poopó.</p> - -<p>Since the early Tertiary strata are themselves deformed from once simple -and approximately horizontal structures and subjected to moderate -tilting and faulting, it follows that mountain-making movements again -affected the region during later Tertiary. They did not, however, -produce extreme effects. They did stimulate erosion and bring about a -reorganization of all the slopes with respect to the new levels.</p> - -<p>This agrees closely with a second line of evidence which rests upon an -independent basis. The alluvial fill which lies upon all the canyon and -valley floors is of glacial origin, as shown by its interlocking -relations with morainal deposits at the valley heads. It is now in -process of dissection and since its deposition in the Pleistocene had -been eroded on the average about 200 feet. Clearly, to form a 3,000-foot -canyon in hard rock requires much more time than to deposit and again -partially to excavate an alluvial fill several<a name="page_196" id="page_196"></a> hundred feet deep. -Moreover, the glacial material is coarse throughout, and was built up -rapidly and dissected rapidly. In most cases, furthermore, coarse -material at the bottom of the glacial series rests directly upon the -rock of a narrow and ungraded valley floor. From these and allied facts -it is concluded that there is no long time interval represented by the -transitions from degrading to aggrading processes and back again. The -early Pleistocene, therefore, seems quite too short a period in which to -produce the bold forms and effect the deep erosion which marks the -period between the close of the mature cycle and the beginnings of -deposition in the Pleistocene.</p> - -<p>The alternative conclusion is that the greater part of the canyon -cutting was effected in the late Tertiary, and that it continued into -the early Pleistocene until further erosion was halted by changed -climatic conditions and the augmented delivery of land waste to all the -streams. The final development of the well-graded high-level slopes is, -therefore, closely confined to a small portion of the Tertiary. The -closest estimate which the facts support appears to be Miocene or early -Pliocene. It is clear, however, that only the culmination of the period -can be definitely assigned. Erosion was in full progress at the close of -the Cretaceous and by middle Tertiary had effected vast changes in the -landscape. The Tertiary strata are marked by coarse basal deposit and by -thin and very fine top deposits. Though their deformed condition -indicates a period of crustal disturbance, the Tertiary beds give no -indication of wholesale transformations. They indicate chiefly tilting -and moderate and normal faulting. The previously developed effects of -erosion were, therefore, not radically modified. The surface was thus in -large measure prepared by erosion in the early Tertiary for its final -condition of maturity reached during the early Pliocene.</p> - -<p>It seems appropriate, in concluding this chapter, to summarize in its -main outlines the physiography of southern Peru, partly to condense the -extended discussion of the preceding paragraphs, and partly to supply a -background for the three chapters that follow. The outstanding features -are broad plateau areas separated<a name="page_197" id="page_197"></a> by well-defined “Cordilleras.†The -plateau divisions are not everywhere of the same origin. Those southwest -of Cuzco (<a href="#fig_130">Fig. 130</a>), and in the Anta Basin (<a href="#fig_124">Fig. 124</a>), northwest of -Cuzco, are due to prolonged erosion and may be defined as peneplane -surfaces uplifted to a great height. They are now bordered on the one -hand by deep valleys and troughs and basins of erosion and deformation; -and, on the other hand, by residual elevations that owe their present -topography to glacial erosion superimposed upon the normal erosion of -the peneplane cycle. The residuals form true mountain chains like the -Cordillera Vilcanota and Cordillera Vilcapampa; the depressions due to -erosion or deformation or both are either basins like those of Anta and -Cuzco or valleys of the canyon type like the Urubamba canyon; the -plateaus are broad rolling surfaces, the punas of the Peruvian Andes.</p> - -<p>There are two other types of plateaus. The one represents a mature stage -in the erosion cycle instead of an ultimate stage; the other is volcanic -in origin. The former is best developed about Antabamba (Figs. 122 and -123), where again deep canyons and residual ranges form the borders of -the plateau remnants. The latter is well developed above Cotahuasi and -in its simplest form is represented in <a href="#fig_133">133</a> . Its surface is the top -of a vast accumulation of lavas in places over a mile thick. While rough -in detail it is astonishingly smooth in a broad view (<a href="#fig_29">Fig. 29</a>). Above it -rise two types of elevations: first, isolated volcanic cones of great -extent surrounded by huge lava flows of considerable relief; and second, -discontinuous lines of peaks where volcanic cones of less extent are -crowded closely together. The former type is displayed on the Coropuna -Quadrangle, the latter on the Cotahuasi and La Cumbre Quadrangles.</p> - -<p>So high is the elevation of the lava plateau, so porous its soil, so dry -the climate, that a few through-flowing streams gather the drainage of a -vast territory and, as in the Grand Canyon country of our West, they -have at long intervals cut profound canyons. The Arma has cut a deep -gorge at Salamanca; the Cotahuasi runs in a canyon in places 7,000 feet -deep; the Majes heads at the edge<a name="page_198" id="page_198"></a> of the volcanic field in a steep -amphitheatre of majestic proportions.</p> - -<p>Finally, we have the plateaus of the coastal zone. These are plains with -surfaces several thousand feet in elevation separated by gorges several -thousand feet deep. The Pampa de Sihuas is an illustration. The -post-maturely dissected Coast Range separates it from the sea. The -pampas are in general an aggradational product formed in a past age -before uplift initiated the present canyon cycle of erosion. Other -plateaus of the coastal zone are erosion surfaces. The Tablazo de Ica -appears to be of this type. That at Arica, Chile, near the southern -boundary of Peru, is demonstrably of this type with a border on which -marine planation has in places given rise to a broad terrace -effect.<a name="FNanchor_43_43" id="FNanchor_43_43"></a><a href="#Footnote_43_43" class="fnanchor">[43]</a><a name="page_199" id="page_199"></a></p> - -<h3><a name="CHAPTER_XII" id="CHAPTER_XII"></a>CHAPTER XII<br /><br /> -THE WESTERN ANDES: THE MARITIME CORDILLERA OR CORDILLERA OCCIDENTAL</h3> - -<p>T<small>HE</small> Western or Maritime Cordillera of Peru forms part of the great -volcanic field of South America which extends from Argentina to Ecuador. -On the walls of the Cotahuasi Canyon (<a href="#fig_131">Fig. 131</a>), there are exposed over -one hundred separate lava flows piled 7,000 feet deep. They overflowed a -mountainous relief, completely burying a limestone range from 2,000 to -4,000 feet high. Finally, upon the surface of the lava plateau new -mountains were formed, a belt of volcanoes 5,000 feet (1,520 m.) high -and from 15,000 to 20,000 feet (4,570 to 6,100 m.) above the sea. There -were vast mud flows, great showers of lapilli, dust, and ashes, and with -these violent disturbances also came many changes in the drainage. Sixty -miles northeast of Cotahuasi the outlet of an unnamed deep valley was -blocked, a lake was formed, and several hundred feet of sediments were -deposited. They are now wasting rapidly, for they lie in the zone of -alternate freezing and thawing, a thousand feet and more below the -snowline. Some of their bad-land forms look like the solid bastions of -an ancient fortress, while others have the delicate beauty of a Japanese -temple.</p> - -<p>Not all the striking effects of vulcanism belong to the remote geologic -past. A day’s journey northeast of Huaynacotas are a group of lakes only -recently hemmed in by flows from the small craters thereabouts. The -fires in some volcanic craters of the Peruvian Andes are still active, -and there is no assurance that devastating flows may not again inundate -the valleys. In the great Pacific zone or girdle of volcanoes the -earth’s crust is yet so unstable that earthquakes occur every year, and -at intervals of a few years they have destructive force. Cotahuasi was -greatly damaged in 1912; Abancay is shaken every few years; and the -violent earthquakes of Cuzco and Arequipa are historic.<a name="page_200" id="page_200"></a></p> - -<p>On the eastern margin of the volcanic country the flows thin out and -terminate on the summit of a limestone (Cretaceous) plateau. On the -western margin they descend steeply to the narrow west-coast desert. The -greater part of the lava dips beneath the desert deposits; there are a -few intercalated flows in the deposits themselves, and the youngest -flows—limited in number—have extended down over the inner edge of the -desert.</p> - -<p>The immediate coast of southern Peru is not volcanic. It is composed of -a very hard and ancient granite-gneiss which forms a narrow coastal -range (<a href="#fig_171">Fig. 171</a>). It has been subjected to very long and continued -erosion and now exhibits mature erosion forms of great uniformity of -profile and declivity.</p> - -<p>From the outcrops of older rocks beneath the lavas it is possible to -restore in a measure the pre-volcanic topography of the Maritime -Cordillera, In its present altitude it ranges from several thousand to -15,000 feet above sea level. The unburied topography has been smoothed -out; the buried topography is rough (Figs. 29 and 166). The contact -lines between lavas and buried surfaces in the deep Majes and Cotahuasi -valleys are in places excessively serrate. From this, it seems safe to -conclude that the period of vulcanism was so prolonged that great -changes in the unburied relief were effected by the agents of erosion. -Thus, while the dominant process of volcanic upbuilding smoothed the -former rough topography of the Maritime Cordillera, erosion likewise -measurably smoothed the present high extra-volcanic relief in the -central and eastern sections. The effect has been to develop a broad and -sufficiently smooth aspect to the summit topography of the entire Andes -to give them a plateau character. Afterward the whole mountain region -was uplifted about a mile above its former level so that at present it -is also continuously lofty.</p> - -<p>The zone of most intense volcanic action does not coincide with the -highest part of the pre-volcanic topography. If the pre-volcanic relief -were even in a very general way like that which would be exhibited if -the lavas were now removed, we should have to say that the chief -volcanic outbursts took place on the western flank of an old and deeply -dissected limestone range.</p> - -<p><a name="fig_129" id="fig_129"></a></p> - -<p><a name="fig_130" id="fig_130"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_200a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_200a_sml.jpg" width="219" height="332" alt="Fig. 129—Composition of slopes at Puquiura, Vilcabamba -Valley, elevation 9,000 feet (2,740 m.). The second prominent spur -entering the valley on the left has a flattish top unrelated to the rock -structure. Like the spurs on the right its blunt end and flat top -indicate an earlier erosion cycle at a lower elevation." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 129—Composition of slopes at Puquiura, Vilcabamba -Valley, elevation 9,000 feet (2,740 m.). The second prominent spur -entering the valley on the left has a flattish top unrelated to the rock -structure. Like the spurs on the right its blunt end and flat top -indicate an earlier erosion cycle at a lower elevation.</p> - -<p class="caption"><span class="smcap">Fig. 130</span>—Inclined Paleozoic strata truncated by an -undulating surface of erosion at 15,000 feet, southwest of Cuzco.</p> -</div> - -<p><a name="fig_131" id="fig_131"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_200b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_200b_sml.jpg" width="212" height="332" alt="Fig. 131—Terraced valley slopes at Huaynacotas, -Cotahuasi Valley, at 11,500 feet (3,500 m.). Solimana is in the -background. On the floor of the Cotahuasi Canyon fruit trees grow. At -Huaynacotas corn and potatoes are the chief products. The section is -composed almost entirely of lava. There are over a hundred major flows -aggregating 5,000 to 7,000 feet thick." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 131—Terraced valley slopes at Huaynacotas, -Cotahuasi Valley, at 11,500 feet (3,500 m.). Solimana is in the -background. On the floor of the Cotahuasi Canyon fruit trees grow. At -Huaynacotas corn and potatoes are the chief products. The section is -composed almost entirely of lava. There are over a hundred major flows -aggregating 5,000 to 7,000 feet thick.</p> -</div> - -<p><a name="page_201" id="page_201"></a></p> - -<p>The volume of the lavas is enormous. They are a mile and a half thick, -nearly a hundred miles wide, and of indefinite extent north and south. -Their addition to the Andes, therefore, <i>has greatly broadened the zone -of lofty mountains</i>. Their passes are from 2,000 to 3,000 feet higher -than the passes of the eastern Andes. They have a much smaller number of -valleys sufficiently deep to enjoy a mild climate. Their soil is far -more porous and dry. Their vegetation is more scanty. They more than -double the difficulties of transportation. And, finally, their all but -unpopulated loftier expanses are a great vacant barrier between farms in -the warm valleys of eastern Peru and the ports on the west coast.</p> - -<p>The upbuilding process was not, of course, continuous. There were at -times intervals of quiet, and some of them were long enough to enable -streams to become established. Buried valleys may be observed in a -number of places on the canyon walls, where subsequently lava flows -displaced the streams and initiated new drainage systems. In these quiet -intervals the weathering agents attacked the rock surfaces and formed -soil. There were at least three or four such prolonged periods of -weathering and erosion wherein a land surface was exposed for many -thousands of years, stream systems organized, and a cultivable soil -formed. No evidence has been found, however, that man was there to -cultivate the soil.</p> - -<p>The older valleys cut in the quiet period are mere pygmies beside the -giant canyons of today. The present is the time of dominant erosion. The -forces of vulcanism are at last relatively quiet. Recent flows have -occurred, but they are limited in extent and in effects. They alter only -the minor details of topography and drainage. Were it not for the oases -set in the now deep-cut canyon floors, the lava plateau of the Maritime -Cordillera would probably be the greatest single tract of unoccupied -volcanic country in the world.</p> - -<p>The lava plateau has been dissected to a variable degree. Its high -eastern margin is almost in its original condition. Its western margin -is only a hundred miles from the sea, so that the<a name="page_202" id="page_202"></a> streams have steep -gradients. In addition, it is lofty enough to have a moderate rainfall. -It is, therefore, deeply and generally dissected. Within the borders of -the plateau the degree of dissection depends chiefly upon position with -respect to the large streams. These were in turn located in an -accidental manner. The repeated upbuilding of the surface by the -extensive outflow of liquid rock obliterated all traces of the earlier -drainage. In the Cotahuasi Canyon the existing stream, working down -through a mile of lavas, at last uncovered and cut straight across a -mountain spur 2,000 feet high. Its course is at right angles to that -pursued by the stream that once drained the spur. It is noteworthy that -the Cotahuasi and adjacent streams take northerly courses and join -Atlantic rivers. The older drainage was directly west to the Pacific. -Thus, vulcanism not only broadened the Andes and increased their height, -but also moved the continental divide still nearer the west coast.</p> - -<p>The glacial features of the western or Maritime Cordillera are of small -extent, partly because vulcanism has added a considerable amount of -material in post-glacial time, partly because the climate is so -exceedingly dry that the snowline lies near the top of the country. The -slopes of the volcanic cones are for the most part deeply recessed on -the southern or shady sides. Above 17,500 feet (5,330 m.) the process of -snow and ice excavation still continues, but the tracts that exceed this -elevation are confined to the loftiest peaks or their immediate -neighborhood. There is a distinct difference between the glacial forms -of the eastern or moister and the western or dryer flanks of this -Cordillera. Only peaks like Coropuna and Solimana near the western -border now bear or ever bore snowfields and glaciers. By contrast the -eastern aspect is heavily glaciated. On La Cumbre Quadrangle, there is a -huge glacial trough at 16,000 feet (4,876 m.), and this extends with -ramifications up into the snowfields that formerly included the highest -country. Prolonged glacial erosion produced a full set of topographic -forms characteristic of the work of Alpine glaciers. Thus, each of the -main mountain chains that make up the Andean system has, like the system -as a whole, a relatively more-dry and a<a name="page_203" id="page_203"></a> relatively less-dry aspect. The -snowline is, therefore, canted from west to east on each chain as well -as on the system. However, this effect is combined with a solar effect -in an unequal way. In the driest places the solar factor is the more -efficient and the snowline is there canted from north to south.<a name="page_204" id="page_204"></a></p> - -<h3><a name="CHAPTER_XIII" id="CHAPTER_XIII"></a>CHAPTER XIII<br /><br /> -THE EASTERN ANDES: THE CORDILLERA VILCAPAMPA</h3> - -<p>T<small>HE</small> culminating range of the eastern Andes is the so-called Cordillera -Vilcapampa. Its numerous, sharp, snow-covered peaks are visible in every -summit view from the central portion of the Andean system almost to the -western border of the Amazon basin. Though the range forms a water -parting nearly five hundred miles long, it is crossed in several places -by large streams that flow through deep canyons bordered by precipitous -cliffs. The Urubamba between Torontoy and Colpani is the finest -illustration. For height and ruggedness the Vilcapampa mountains are -among the most noteworthy in Peru. Furthermore, they display glacial -features on a scale unequaled elsewhere in South America north of the -ice fields of Patagonia.</p> - -<h4>GLACIERS AND GLACIAL FORMS</h4> - -<p>One of the most impressive sights in South America is a tropical forest -growing upon a glacial moraine. In many places in eastern Bolivia and -Peru the glaciers of the Ice Age were from 5 to 10 miles long—almost -the size of the Mer de Glace or the famous Rhone glacier. In the Juntas -Valley in eastern Bolivia the tree line is at 10,000 feet (3,050 m.), -but the terminal moraines lie several thousand feet lower. In eastern -Peru the glaciers in many places extended down nearly to the tree line -and in a few places well below it. In the Cordillera Vilcapampa vast -snowfields and glacier systems were spread out over a summit area as -broad as the Southern Appalachians. The snowfields have since shrunk to -the higher mountain recesses; the glaciers have retreated for the most -part to the valley heads or the cirque floors; and the lower limit of -perpetual snow has been raised to 15,500 feet.</p> - -<div class="figcenter"> -<a href="images/ill_page_204a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_204a_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_204a_sml.jpg" width="374" height="421" alt="" /> -</div> - -<p><a name="fig_132" id="fig_132"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_204b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_204b_sml.jpg" width="211" height="322" alt="Fig. 132—Recessed volcanoes in the right background and -eroded tuffs, ash beds, and lava flows on the left. Maritime Cordillera -above Cotahuasi." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 132—Recessed volcanoes in the right background and -eroded tuffs, ash beds, and lava flows on the left. Maritime Cordillera -above Cotahuasi.<a name="fig_133" id="fig_133"></a></p> - -<p class="caption"><span class="smcap">Fig. 133</span>—The summit of the great lava plateau above -Cotahuasi on the trail to Antabamba. The lavas are a mile and a half in -thickness. The elevation is 16,000 feet. Hence the volcanoes in the -background, 17,000 feet above sea level, are mere hills on the surface -of the lofty plateau.</p> -</div> - -<p><a name="fig_134" id="fig_134"></a></p> -<p><a name="fig_135" id="fig_135"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_204c_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_204c_sml.jpg" width="209" height="324" alt="Fig. 134—Southwestern aspect of the Cordillera -Vilcapampa between Anta and Urubamba from Lake Huaipo. Rugged summit -topography in the background, graded post-mature slopes in the middle -distance, and solution lake in limestone in the foreground." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 134—Southwestern aspect of the Cordillera -Vilcapampa between Anta and Urubamba from Lake Huaipo. Rugged summit -topography in the background, graded post-mature slopes in the middle -distance, and solution lake in limestone in the foreground.</p> - -<p class="caption"><span class="smcap">Fig. 135</span>—Summit view, Cordillera Vilcapampa. There are -fifteen glaciers represented in this photograph. The camera stands on -the summit of a minor divide in the zone of nivation.</p> -</div> - -<p><a name="page_205" id="page_205"></a></p> - -<p>These features are surprising because neither Whymper<a name="FNanchor_44_44" id="FNanchor_44_44"></a><a href="#Footnote_44_44" class="fnanchor">[44]</a> nor Wolf<a name="FNanchor_45_45" id="FNanchor_45_45"></a><a href="#Footnote_45_45" class="fnanchor">[45]</a> -mentions the former greater extent of the ice on the volcanoes of -Ecuador, only ten or twelve degrees farther north. Moreover, Reiss<a name="FNanchor_46_46" id="FNanchor_46_46"></a><a href="#Footnote_46_46" class="fnanchor">[46]</a> -denies that the hypothesis of universal climatic change is supported by -the facts of a limited glaciation in the High Andes of Ecuador; and J. -W. Gregory<a name="FNanchor_47_47" id="FNanchor_47_47"></a><a href="#Footnote_47_47" class="fnanchor">[47]</a> completely overlooks published proof of the existence of -former more extensive glaciers elsewhere in the Andes:</p> - -<p>“... the absence not only of any traces of former more extensive -glaciation from the tropics, as in the Andes and Kilimandjaro, but also -from the Cape.†He says further: “In spite of the extensive glaciers now -in existence on the higher peaks of the Andes, there is practically no -evidence of their former greater extension.â€(!)</p> - -<p>Whymper spent most of his time in exploring recent volcanoes or those -recently in eruption, hence did not have the most favorable -opportunities for gathering significant data. Reiss was carried off his -feet by the attractiveness of the hypothesis<a name="FNanchor_48_48" id="FNanchor_48_48"></a><a href="#Footnote_48_48" class="fnanchor">[48]</a> relating to the effect -of glacial denudation on the elevation of the snowline. Gregory appeared -not to have recognized the work of Hettner on the Cordillera of Bogotá -and of Sievers<a name="FNanchor_49_49" id="FNanchor_49_49"></a><a href="#Footnote_49_49" class="fnanchor">[49]</a> and Acosta on the Sierra Nevada de Santa Marta in -northern Colombia.</p> - -<p>The importance of the glacial features of the Cordillera Vilcapampa -developed on a great scale in very low latitudes in the southern -hemisphere is twofold: first, it bears on the still unsettled problem of -the universality of a colder climate in the Pleistocene, and, second, it -supplies additional data on the relative depression of the snowline in -glacial times in the tropics. <a name="page_206" id="page_206"></a>Snow-clad mountains near the equator are -really quite rare. Mount Kenia rising from a great jungle on the -equator, Kilimandjaro with its two peaks, Kibo and Mawenzi, two hundred -miles farther south, and Ingomwimbi in the Ruwenzori group thirty miles -north of the equator, are the chief African examples. A few mountains -from the East Indies, such as Kinibalu in Borneo, latitude 6° north, -have been found glaciated, though now without a snow cover. In higher -latitudes evidences of an earlier extensive glaciation have been -gathered chiefly from South America, whose extension 13° north and 56° -south of the equator, combined with the great height of its dominating -Cordillera, give it unrivaled distinction in the study of mountain -glaciation in the tropics.</p> - -<p>Furthermore, mountain summits in tropical lands are delicate climatic -registers. In this respect they compare favorably with the inclosed -basins of arid regions, where changes in climate are clearly recorded in -shoreline phenomena of a familiar kind. Lofty mountains in the tropics -are in a sense inverted basins, the lower snowline of the past is like -the higher shoreline of an interior basin; the terminal moraines and the -alluvial fans in front of them are like the alluvial fans above the -highest strandline; the present snow cover is restricted to mountain -summits of small areal extent, just as the present water bodies are -restricted to the lowest portions of the interior basin; and successive -retreatal stages are marked by terminal moraines in the one case as they -are marked in the other by flights of terraces and beach ridges.</p> - -<p>I made only a rapid reconnaissance across the Cordillera Vilcapampa in -the winter season, and cannot pretend from my limited observations to -solve many of the problems of the field. The data are incorporated -chiefly in the chapter on Glacial Features. In this place it is proposed -to describe only the more prominent glacial features, leaving to later -expeditions the detailed descriptions upon which the solution of some of -the larger problems must depend.</p> - -<p>At Choquetira three prominent stages in the retreat of the ice are -recorded. The lowermost stage is represented by the great fill of -morainic and outwash material at the junction of the Choquetira,<a name="page_207" id="page_207"></a> and an -unnamed valley farther south at an elevation of 11,500 feet (3,500 m.). -A mile below Choquetira a second moraine appears, elevation 12,000 feet -(3,658 m.), and immediately above the village a third at 12,800 (3,900 -m.). The lowermost moraine is well dissected, the second is ravined and -broken but topographically distinct, the third is sharp-crested and -regular. A fourth though minor stage is represented by the moraine at -the snout of the living glacier and still less important phases are -represented in some valleys—possibly the record of post-glacial changes -of climate. Each main moraine is marked by an important amount of -outwash, the first and third moraines being associated with the greatest -masses. The material in the moraines represents only a part of that -removed to form the successive steps in the valley profile. The -lowermost one has an enormous volume, since it is the oldest and was -built at a time when the valley was full of waste. It is fronted by a -deep fill, over the dissected edge of which one may descend 800 feet in -half an hour. It is chiefly alluvial in character, whereas the next -higher one is composed chiefly of bowlders and is fronted by a -pronounced bowlder train, which includes a remarkable perched bowlder of -huge size. Once the valley became cleaned out the ice would derive its -material chiefly by the slower process of plucking and abrasion, hence -would build much smaller moraines during later recessional stages, even -though the stages were of equivalent length.</p> - -<p><a name="fig_136" id="fig_136"></a></p> - -<div class="figright" style="width: 117px;"> -<a href="images/ill_page_207_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_207_sml.jpg" width="117" height="120" alt="Fig. 136—Glacial sculpture on the southwestern flank of -the Cordillera Vilcapampa. Flat-floored valleys and looped terminal -moraines below and glacial steps and hanging valleys are characteristic. -The present snowfields and glaciers are shown by dotted contours." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 136—Glacial sculpture on the southwestern flank of -the Cordillera Vilcapampa. Flat-floored valleys and looped terminal -moraines below and glacial steps and hanging valleys are characteristic. -The present snowfields and glaciers are shown by dotted contours.</p> -</div> - -<p>There is a marked difference in the degree of dissection of the<a name="page_208" id="page_208"></a> -moraines. The lowermost and oldest is so thoroughly dissected as to -exhibit but little of its original surface. The second has been greatly -modified, but still possesses a ridge-like quality and marks the -beginning of a noteworthy flattening of the valley gradient. The third -is as sharp-crested as a roof, and yet was built so long ago that the -flat valley floor behind it has been modified by the meandering stream. -From this point the glacier retreated up-valley several miles -(estimated) without leaving more than the thinnest veneer on the valley -floor. The retreat must, therefore, have been rapid and without even -temporary halts until the glacier reached a position near that occupied -today. Both the present ice tongues and snowfields and those of a past -age are emphasized by the presence of a patch of scrub and woodland that -extends on the north side of the valley from near the snowline down over -the glacial forms to the lower valley levels.</p> - -<p>The retreatal stages sketched above would call for no special comment if -they were encountered in mountains in northern latitudes. They would be -recognized at once as evidence of successive periodic retreats of the -ice, due to successive changes in temperature. To understand their -importance when encountered in very low latitudes it is necessary to -turn aside for a moment and consider two rival hypotheses of glacial -retreat. First we have the hypothesis of periodic retreat, so generally -applied to terminal moraines and associated outwash in glaciated -mountain valleys. This implies also an advance of the ice from a higher -position, the whole taking place as a result of a climatic change from -warmer to colder and back again to warmer.</p> - -<p><a name="fig_137" id="fig_137"></a></p> - -<p><a name="fig_138" id="fig_138"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_208a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_208a_sml.jpg" width="211" height="327" alt="Fig. 137—Looking up a spurless flat-floored glacial -trough near the Chucuito pass in the Cordillera Vilcapampa from 14,200 -feet (4,330 m.). Note the looped terminal and lateral moraines on the -steep valley wall on the left. A stone fence from wall to wall serves to -inclose the flock of the mountain shepherd." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 137—Looking up a spurless flat-floored glacial -trough near the Chucuito pass in the Cordillera Vilcapampa from 14,200 -feet (4,330 m.). Note the looped terminal and lateral moraines on the -steep valley wall on the left. A stone fence from wall to wall serves to -inclose the flock of the mountain shepherd.</p> - -<p class="caption"><span class="smcap">Fig. 138</span>—Terminal moraine in the glaciated Choquetira -Valley below Choquetira. The people who live here have an abundance of -stones for building corrals and stone houses. The upper edge of the -timber belt (cold timber line) is visible beyond the houses. Elevation -12,100 feet (3,690 m.).</p> -</div> - -<p>But evidences of more extensive mountain glaciation in the past do not -in themselves prove a change in climate over the whole earth. In an -epoch of fixed climate a glacier system may so deeply and thoroughly -erode a mountain mass, that the former glaciers may either diminish in -size or disappear altogether. As the work of excavation proceeds, the -catchment basins are sunk to, and at last below, the snowline; broad -tributary spurs whose snows nourish the glaciers, may be reduced to -narrow or skeleton ridges with little snow to contribute to the valleys -on either hand; the<a name="page_209" id="page_209"></a> glaciers retreat and at last disappear. There -would be evidences of glaciation all about the ruins of the former -loftier mountain, but there would be no living glaciers. And yet the -climate might remain the same throughout.</p> - -<p>It is this “topographic†hypothesis that Reiss and Stübel accept for the -Ecuadorean volcanoes. Moreover, the volcanoes of Ecuador are practically -on the equator—a very critical situation when we wish to use the facts -they exhibit in the solution of such large problems as the -contemporaneous glaciation of the two hemispheres, or the periodic -advance and retreat of the ice over the whole earth. This is not the -place to scrutinize either their facts or their hypothesis, but I am -under obligations to state very emphatically that the glacial features -of the Cordillera Vilcapampa require the climatic and not the -topographic hypothesis. Let us see why.</p> - -<p>The differences in degree of dissection and the flattening gradient -up-valley that we noted in a preceding paragraph leave no doubt that -each moraine of the bordering valleys in the Vilcapampa region, -represents a prolonged period of stability in the conditions of -topography as well as of temperature and precipitation. If change in -topographic conditions is invoked to explain retreat from one position -to the other there is left no explanation of the periodicity of retreat -which has just been established. If a period of cold is inaugurated and -glaciers advance to an ultimate position, they can retreat only through -change of climate effected either by general causes or by topographic -development to the point where the snowfields become restricted in size. -In the case of climatic change the ice changes are periodic. In the case -of retreat due to topographic change there should be a steady or -non-periodic falling back of the ice front as the catchment basins -decrease in elevation and the snow-gathering ridges tributary to them -are reduced in height.</p> - -<p>Further, the matterhorns of the Cordillera Vilcapampa are not bare but -snow-covered, vigorous glaciers several miles in length and large -snowfields still survive and the divides are not arêtes but broad -ridges. In addition, the last two moraines, composed<a name="page_210" id="page_210"></a> of very loose -material, are well preserved. They indicate clearly that the time since -their formation has witnessed no wholesale topographic change. If (1) no -important topographic changes have taken place, and (2) a vigorous -glacier lay for a long period back of a given moraine, and (3) <i>suddenly -retreated several miles and again became stable</i>, we are left without -confidence in the application of the topographic hypothesis to the -glacial features of the Vilcapampa region. Glacial retreat may be -suddenly begun in the case of a late stage of topographic development, -but it should be an orderly retreat marked by a large number of small -moraines, or at least a plentiful strewing of the valley floor with -débris.</p> - -<p><a name="fig_139" id="fig_139"></a></p> - -<div class="figleft" style="width: 118px;"> -<a href="images/ill_page_210_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_210_sml.jpg" width="118" height="141" alt="Fig. 139—Glacial features on the eastern slopes of the -Cordillera Vilcapampa." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 139—Glacial features on the eastern slopes of the -Cordillera Vilcapampa.</p> -</div> - -<p>The number of moraines in the various glaciated valleys of the -Cordillera Vilcapampa differ, owing to differences in elevation and to -the variable size of the catchment basins. All valleys, however, display -the same sudden change from moraine to moraine and the same -characteristics of gradient. In all of them the lowermost moraine is -always more deeply eroded than the higher moraines, in all of them -glacial erosion was sufficiently prolonged greatly to modify the valley -walls, scour out lake basins, or broad flat valley floors, develop -cirques, arêtes, and pinnacled ridges in limited number. In some, -glaciation was carried to the point where only skeleton divides -remained, in most places broad massive ridges or mountain knots persist. -In spite of all these differences successive moraines were formed, -separated by long stretches either thinly covered with till or exposing -bare rock.<a name="page_211" id="page_211"></a></p> - -<p>In examining this group of features it is important to recognize the -essential fact that though the number of moraines varies from valley to -valley, the differences in character between the moraines at low and at -high elevations in a single valley are constant. It is also clear that -everywhere the ice retreated and advanced periodically, no matter with -what topographic features it was associated, whether those of maturity -or of youth in the glacial cycle. We, therefore, conclude that -topographic changes had no significant part to play in the glacial -variations in the Cordillera Vilcapampa.</p> - -<p>The country west of the Cordillera Vilcapampa had been reduced to early -topographic maturity before the Ice Age, and then uplifted with only -moderate erosion of the masses of the interfluves. That on the east had -passed through the same sequence of events, but erosion had been carried -much farther. The reason for this is found in a strong climatic -contrast. The eastern is the windward aspect and receives much more rain -than the western. Therefore, it has more streams and more rapid -dissection. The result was that the eastern slopes were cut to pieces -rapidly after the last great regional uplift; the broad interfluves were -narrowed to ridges. The region eastward from the crest of the Cordillera -to the Pongo de Mainique looks very much like the western half of the -Cascade Mountains in Oregon—the summit tracts of moderate declivity are -almost all consumed.</p> - -<p>The effect of these climatic and topographic contrasts is manifested in -strong contrasts in the position and character of the glacial forms on -the opposite slopes of the range. At Pampaconas on the east the -lowermost terminal moraine is at least a thousand feet below timber -line. Between Vilcabamba pueblo and Puquiura the terminal moraine lies -at 11,200 feet (3,414 m.). By contrast the largest Pleistocene glacier -on the western slope, nearly twelve miles long, and the largest along -the traverse, ended several miles below Choquetira at 11,500 feet (3,504 -m.) elevation, or just at the timber line. Thus, the steeper descents of -the eastern side of the range appear to have carried short glaciers to -levels far lower than those attained by the glaciers of the western -slope.<a name="page_212" id="page_212"></a></p> - -<p>It seems at first strange that the largest glaciers were west of the -divide between the Urubamba and the Apurimac, that is, on the relatively -dry side of the range. The reason lies in a striking combination of -topographic and climatic conditions. Snow is a mobile form of -precipitation that is shifted about by the wind like a sand dune in the -desert. It is not required, like water, to begin a downhill movement as -soon as it strikes the earth. Thus, it is a noteworthy fact that snow -drifting across the divides may ultimately cause the largest snowfields -to lie where the least snow actually falls. This is illustrated in the -Bighorns of Wyoming and others of our western ranges. It is, however, -not the wet snow near the snowline, but chiefly the dry snow of higher -altitudes that is affected. What is now the dry or leeward side of the -Cordillera appears in glacial times to have actually received more snow -than the wet windward side.</p> - -<p><a name="fig_140" id="fig_140"></a></p> - -<div class="figleft" style="width: 115px;"> -<a href="images/ill_page_212_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_212_sml.jpg" width="115" height="179" alt="Fig. 140—Glacial sculpture in the heart of the -Cordillera Vilcapampa. In places the topography has so high a relief -that the glaciers seem almost to overhang the valleys. See Figs. 96 and -179 for photographs." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 140—Glacial sculpture in the heart of the -Cordillera Vilcapampa. In places the topography has so high a relief -that the glaciers seem almost to overhang the valleys. See Figs. <a href="#fig_96">96</a> and -<a href="#fig_179">179</a> for photographs.</p> -</div> - -<p>The topography conspired to increase this contrast. In place of many -streams, direct descents, a dispersion of snow in many valleys, as on -the east, the western slopes had indirect descents, gentler valley -profiles, and that higher degree of concentration of drainage which -naturally goes with topographic maturity. For example, there is nothing -in the east to compare with the big spurless valley near the pass above -Arma. The side walls were so<a name="page_213" id="page_213"></a> extensively trimmed that the valley was -turned into a trough. The floor was smoothed and deepened and all the -tributary glaciers were either left high up on the bordering slopes or -entered the main valley with very steep profiles; their lateral and -terminal moraines now hang in festoons on the steep side walls. -Moreover, the range crest is trimmed from the west so that the serrate -skyline is a feature rarely seen from eastern viewpoints. This may not -hold true for more than a small part of the Cordillera. It was probably -emphasized here less by the contrasts already noted than by the geologic -structure. The eastward-flowing glaciers descended over dip slopes on -highly inclined sandstones, as at Pampaconas. Those flowing westward -worked either in a jointed granite or on the outcropping <i>edges</i> of the -sandstones, where the quarrying process known as glacial plucking -permitted the development of excessively steep slopes.</p> - -<p>There are few glacial steps in the eastern valleys. The western valleys -have a marvelous display of this striking glacial feature. The -accompanying hachure maps show them so well that little description is -needed. They are from 50 to 200 feet high. Each one has a lake at its -foot into which the divided stream trickles over charming waterfalls. -All of them are clearly associated with a change in the volume of the -glacier that carved the valley. Wherever a tributary glacier entered, or -the side slopes increased notably in area, a step was formed. By retreat -some of them became divided, for the process once begun would push the -step far up valley after the manner of an extinguishing waterfall.</p> - -<p>The retreat of the steps, the abrasion of the rock, and the sapping of -the cirques at the valley heads excavated the upper valleys so deeply -that they are nearly all, as W. D. Johnson has put it, “down at the -heel.†Thus, above Arma, one plunges suddenly from the smooth, grassy -glades of the strongly glaciated valley head down over the outer slopes -of the lowermost terminal moraine to the steep lower valley. Above the -moraine are fine pastures, in the steep valley below are thickets and -rocky defiles. There are long quiet reaches in the streams of the -glaciated valley<a name="page_214" id="page_214"></a> heads besides pretty lakes and marshes. Below, the -stream is swift, almost torrential. Arma itself is built upon alluvial -deposits of glacial origin. A mile farther down the valley is -constricted and steep-walled—really a canyon.</p> - -<p>Though the glaciers have retreated to the summit region, they are by no -means nearing extinction. The clear blue ice of the glacier descending -from Mt. Soiroccocha in the Arma Valley seems almost to hang over the -precipitous valley border. In curious contrast to its suggestion of cold -and storm is the patch of dark green woodland which extends right up to -its border. An earthquake might easily cause the glacier to invade the -woodland. Some of the glaciers between Choquetira and Arma rest on -terminal moraines whose distal faces are from 200 to 300 feet high. The -ice descending southeasterly from Panta Mt. is a good illustration. -Earlier positions of the ice front are marked by equally large moraines. -The one nearest that engaged by the living glacier confines a large lake -that discharges through a gap in the moraine and over a waterfall to the -marshy floor of the valley.</p> - -<p>Retreat has gone so far, however, that there are only a few large -glacier systems. Most of the tributaries have withdrawn toward their -snowfields. In place of the twenty distinct glaciers now lying between -the pass and the terminal moraine below Choquetira, there was in glacial -times one great glacier with twenty minor tributaries. The cirques now -partly filled with damp snow must then have been overflowing with dry -snow above and ice below. Some of the glaciers were over a thousand feet -thick; a few were nearly two thousand feet thick, and the cirques that -fed them held snow and ice at least a half mile deep. Such a remarkably -complete set of glacial features only 700 miles from the equator is -striking evidence of the moist climate on the windward eastern part of -the great Andean Cordillera, of the universal change in climate in the -glacial period, and of the powerful dominating effects of ice erosion in -this region of unsurpassed Alpine relief.<a name="page_215" id="page_215"></a></p> - -<h4>THE VILCAPAMPA BATHOLITH AND ITS TOPOGRAPHIC EFFECTS</h4> - -<p><a name="fig_141" id="fig_141"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_215_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_215_sml.jpg" width="211" height="47" alt="Fig. 141—Composite geologic section on the northeastern -border of the Cordillera Vilcapampa, in the vicinity of Pampaconas, to -show the deformative effects of the granite intrusion. There is a -limited amount of limestone near the border of the Cordillera. Both -limestone and sandstone are Carboniferous. See Appendix B. See also -Figs. 142 and 146. The section is about 15 miles long." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 141—Composite geologic section on the northeastern -border of the Cordillera Vilcapampa, in the vicinity of Pampaconas, to -show the deformative effects of the granite intrusion. There is a -limited amount of limestone near the border of the Cordillera. Both -limestone and sandstone are Carboniferous. See <a href="#APPENDIX_B">Appendix B</a>. See also -Figs. <a href="#fig_142">142</a> and <a href="#fig_146">146</a>. The section is about 15 miles long.</p> -</div> - -<p>The main axis of the Cordillera Vilcapampa consists of granite in the -form of a batholith between crystalline schists on the one hand -(southwest), and Carboniferous limestones and sandstones and Silurian -shales and slates on the other (northeast). It is not a domal uplift in -the region in which it was observed in 1911, but an axial intrusion, in -places restricted to a narrow belt not more than a score of miles -across. As we should expect from the variable nature of the invaded -material, the granite belt is not uniform in width nor in the character -of its marginal features. In places the intrusion has produced -strikingly little alteration of the country rock; in other localities -the granite has been injected into the original material in so intimate -a manner as almost completely to alter it, and to give rise to a very -broad zone of highly metamorphosed rock. Furthermore, branches were -developed so that here and there tributary belts of granite extend from -the main mass to a distance of many miles. Outlying batholiths occur -whose common petrographic character and similar manner of occurrence -leave little doubt that they are related abyssally to a common plutonic -mass.</p> - -<p>The Vilcapampa batholith has two highly contrasted borders, whether we -consider the degree of metamorphism of the country rock, the definition -of the border, or the resulting topographic forms. On the northeastern -ridge at Colpani the contact is so sharp that the outstretched arms in -some places embrace typical<a name="page_216" id="page_216"></a> granite on the one hand and almost -unaltered shales and slates on the other. Inclusions or xenoliths of -shale are common, however, ten and fifteen miles distant, though they -are prominent features in a belt only a few miles wide. The lack of more -intense contact effects is a little remarkable in view of the altered -character of the inclusions, all of which are crystalline in contrast to -the fissile shales from which they are chiefly derived. Inclusions -within a few inches of the border fall into a separate class, since they -show in general but trifling alteration and preserve their original -cleavage plains. It appears that the depth of the intrusion must have -been relatively slight or the intrusion sudden, or both shallow and -sudden, conditions which produce a narrow zone of metamorphosed material -and a sharp contact.</p> - -<p><a name="fig_142" id="fig_142"></a></p> - -<div class="figleft" style="width: 204px;"> -<a href="images/ill_page_216a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_216a_sml.jpg" width="104" height="30" alt="Fig. 142—The deformative effects of the Vilcapampa -intrusion on the northeastern border of the Cordillera. The deformed -strata are heavy-bedded sandstones and shales and the igneous rocks are -chiefly granites with bordering porphyries. Looking northwest near -Puquiura. For conditions near Pampaconas, looking in the opposite -direction, see Fig. 141. For conditions on the other side of the -Cordillera, see Fig. 146." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 142—The deformative effects of the Vilcapampa -intrusion on the northeastern border of the Cordillera. The deformed -strata are heavy-bedded sandstones and shales and the igneous rocks are -chiefly granites with bordering porphyries. Looking northwest near -Puquiura. For conditions near Pampaconas, looking in the opposite -direction, see Fig. <a href="#fig_141">141</a>. For conditions on the other side of the -Cordillera, see Fig. <a href="#fig_146">146</a>.</p> -</div> - -<p>The relation between shale and granite at Colpani is shown in <a href="#fig_143">143</a> . -Projections of granite extend several feet into the shale and slate and -generally end in blunt barbs or knobs. In a few places there is an -intimate mixture of irregular slivers and blocks of crystallized -sediments in a granitic groundmass, with sharp lines of demarcation -between igneous and included material. The contact is vertical for at -least several miles. It is probable that other localities on the contact -exhibit much greater modification and invasion of the weak shales and -slates, but at Colpani the phenomena are both simple and restricted in -development.</p> - -<p><a name="fig_143" id="fig_143"></a></p> - -<div class="figright" style="width: 206px;"> -<a href="images/ill_page_216b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_216b_sml.jpg" width="106" height="45" alt="Fig. 143—Relation of granite intrusion to schist on the -northeastern border of the Vilcapampa batholith near the bridge of -Colpani, lower end of the granite Canyon of Torontoy. The sections are -from 15 to 25 feet high and represent conditions at different levels -along the well-defined contact." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 143—Relation of granite intrusion to schist on the -northeastern border of the Vilcapampa batholith near the bridge of -Colpani, lower end of the granite Canyon of Torontoy. The sections are -from 15 to 25 feet high and represent conditions at different levels -along the well-defined contact.</p> -</div> - -<p><a name="page_217" id="page_217"></a></p> - -<p>The highly mineralized character of the bordering sedimentary strata, -and the presence of numbers of complementary dikes, nearly identical in -character to those in the parent granite now exposed by erosion over a -broad belt roughly parallel to the contact, supplies a basis for the -inference that the granite may underlie the former at a slight depth, or -may have had far greater metamorphic effects upon its sedimentary roof -than the intruded granite has had upon its sedimentary rim.</p> - -<p>The physiographic features of the contact belt are of special interest. -No available physiographic interpretation of the topography of a -batholith includes a discussion of those topographic and drainage -features that are related to the lithologic character of the intruded -rock, the manner of its intrusion, or the depth of erosion since -intrusion. Yet each one of these factors has a distinct topographic -effect. We shall, therefore, turn aside for a moment from the detailed -discussion of the Vilcapampa region to an examination of several -physiographic principles and then return to the main theme for -applications.</p> - -<p>It is recognized that igneous intrusions are of many varieties and that -even batholithic invasions may take place in rather widely different -ways. Highly heated magmas deeply buried beneath the earth’s surface -produce maximum contact effects, those nearer the surface may force the -strata apart without extreme lithologic alterations of the displaced -beds, while through the stoping process a sedimentary cover may be -largely absorbed and the magmas may even break forth at the surface as -in ordinary vulcanism. If the sedimentary beds have great vertical -variation in resistance, in attitude, and in composition, there may be -afforded an opportunity for the display of quite different effects at -different levels along a given contact, so that a great variety of -physical conditions will be passed by the descending levels of erosion. -At one place erosion may have exposed only the summit of the batholith, -at another the associated dikes and sheets and ramifying branches may be -exposed as in the zone of fracture, at a third point the original zone -of flowage may be reached with characteristic marginal schistosity, -while at still greater depths<a name="page_218" id="page_218"></a> there may be uncovered a highly -metamorphosed rim of resistant sedimentary rock.</p> - -<p>The mere enumeration of these variable structural features is sufficient -to show how variable we should expect the associated land forms to be. -Were the forms of small extent, or had they but slight distinction upon -comparison with other erosional effects, they would be of little -concern. They are, on the contrary, very extensively developed; they -affect large numbers of lofty mountain ranges besides still larger areas -of old land masses subjected to extensive and deep erosion, thus laying -bare many batholiths long concealed by a thick sedimentary roof.</p> - -<p>The differences between intruded and country rock dependent upon these -diversified conditions of occurrence are increased or diminished -according to the history of the region after batholithic invasion takes -place. Regional metamorphism may subsequently induce new structures or -minimize the effects of the old. Joint systems may be developed, the -planes widely spaced in one group of rocks giving rise to monolithic -masses very resistant to the agents of weathering, while those of an -adjacent group may be so closely spaced as greatly to hasten the rate of -denudation. There may be developed so great a degree of schistosity in -one rock as to give rise (with vigorous erosion) to a serrate -topography; on the other hand the forms developed on the rocks of a -batholith may be massive and coarse-textured.</p> - -<p>To these diversifying conditions may be added many others involving a -large part of the field of dynamic geology. It will perhaps suffice to -mention two others: the stage of erosion and the special features -related to climate. If a given intrusion has been accompanied by an -important amount of uplift or marginal compression, vigorous erosion may -follow, whereupon a chance will be offered for the development of the -greatest contrast in the degree of boldness of topographic forms -developed upon rocks of unequal resistance. Ultimately these contrasts -will diminish in intensity, as in the case of all regional differences -of relief, with progress toward the end of the normal cycle of erosion. -If peneplanation ensue, only feeble topographic differences may mark<a name="page_219" id="page_219"></a> -the line of contact which was once a prominent topographic feature. With -reference to the effects of climate it may be said simply that a granite -core of batholithic origin may extend above the snowline or above timber -line or into the timbered belt, whereas the invaded rock may occur -largely below these levels with obvious differences in both the rate and -the kind of erosion affecting the intruded mass.</p> - -<p><a name="fig_144" id="fig_144"></a></p> -<p><a name="fig_145" id="fig_145"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_218a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_218a_sml.jpg" width="309" height="208" alt="Fig. 144—Cliffed canyon wall in the Urubamba Valley -between Huadquiña and Torontoy. There is a descent of nearly 2,000 feet -shown in the photograph and it is developed almost wholly along -successive joint planes." /></a> -<br /> - -<table border="0" cellpadding="5" cellspacing="0" summary=""> -<tr valign="top"><td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 144—Cliffed canyon wall in the Urubamba Valley -between Huadquiña and Torontoy. There is a descent of nearly 2,000 feet -shown in the photograph and it is developed almost wholly along -successive joint planes.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig. 145</span>—Another aspect of the canyon wall of <a href="#fig_144">144</a> . -The almost sheer descents are in contrast with the cliff and platform -type of topography characteristic of the Grand Canyon of Colorado.</p></td></tr></table> -</div> - -<p>If we apply the foregoing considerations to the Cordillera Vilcapampa, -we shall find some striking illustrations of the principles involved. -The invasion of the granite was accompanied by moderate absorption of -the displaced rock, and more especially by the marginal pushing aside of -the sedimentary rim. The immediate effect must have been to give both -intruded rock and country rock greater height and marked ruggedness. -There followed a period of regional compression and torsion, and the -development of widespread joint systems with strikingly regular -features. In the Silurian shales and slates these joints are closely -spaced; in the granites they are in many places twenty to thirty feet -apart. The shales, therefore, offer many more points of attack and have -weathered down into a smooth-contoured topography boldly overlooked -along the contact by walls and peaks of granite. <i>In some cases a canyon -wall a mile high is developed entirely on two or three joint planes -inclined at an angle no greater than 15°.</i> The effect in the granite is -to give a marked boldness of relief, nowhere more strikingly exhibited -than at Huadquiña, below Colpani, where the foot-hill slopes developed -on shales and slates suddenly become moderate. The river flows from a -steep and all but uninhabited canyon into a broad valley whose slopes -are dotted with the terraced <i>chacras</i>, or farms, of the mountain -Indians.</p> - -<p>The Torontoy granite is also homogeneous while the shales and slates -together with their more arenaceous associates occur in alternating -belts, a diversity which increases the points of attack and the -complexity of the forms. Tending toward the same result is the greater -hardness of the granite. The tendency of the granite to develop bold -forms is accelerated in lofty valleys disposed about snow-clad peaks, -where glaciers of great size once<a name="page_220" id="page_220"></a> existed, and where small glaciers -still linger. The plucking action of ice has an excellent chance for -expression, since the granite may be quarried cleanly without the -production of a large amount of spoil which would load the ice and -diminish the intensity of its plucking action.</p> - -<p>As a whole the Central Andes passed through a cycle of erosion in late -Tertiary time which was interrupted by uplift after the general surface -had been reduced to a condition of topographic maturity. Upon the -granites mature slopes are not developed except under special conditions -(1) of elevation as in the small batholith above Chuquibambilla, and (2) -where the granite is itself bordered by resistant schists which have -upheld the surface over a broad transitional belt. Elsewhere the granite -is marked by exceedingly rugged forms: deep steep-walled canyons, -precipitous cirques, matterhorns, and bold and extended escarpments of -erosion. In the shale belt the trails run from valley to valley in every -direction without special difficulties, but in the granite they follow -the rivers closely or cross the axis of the range by carefully selected -routes which generally reach the limit of perpetual snow. Added interest -attaches to these bold topographic forms because of the ruins now found -along the canyon walls, as at Torontoy, or high up on the summit of a -precipitous spur, as at Machu Picchu near the bridge of San Miguel.</p> - -<p>The Vilcapampa batholith is bordered on the southwest by a series of -ancient schists with which the granite sustains quite different -relations. No sharp dividing line is visible, the granite extending -along the planes of foliation for such long distances as in places to -appear almost interbedded with the schists. The relation is all the more -striking in view of the trifling intrusions effected in the case of the -seemingly much weaker shales on the opposite contact. Nor is the -metamorphism of the invaded rock limited to simple intrusion. For -several miles beyond the zone of intenser effects the schists have been -enriched with quartz to such an extent that their original darker color -has been changed to light gray or dull white. At a distance they may -even appear as homogeneous and light-colored as the granite. At distant<a name="page_221" id="page_221"></a> -points the schists assume a darker hue and take on the characters of a -rather typical mica schist.</p> - -<p>It is probable that the Vilcapampa intrusion is one of a family of -batholiths which further study may show to extend over a much larger -territory. The trail west of Abancay was followed quite closely and -accidentally crosses two small batholiths of peculiar interest. Their -limits were not closely followed out, but were accurately determined at -a number of points and the remaining portion of the contact inferred -from the topography. In the case of the larger area there may indeed be -a connection westward with a larger mass which probably constitutes the -ranges distant some five to ten miles from the line of traverse.</p> - -<p><a name="fig_146" id="fig_146"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_221_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_221_sml.jpg" width="214" height="43" alt="Fig. 146—Deformative effects on limestone strata of the -granite intrusion on the southwestern border of the Vilcapampa batholith -above Chuquibambilla. Fig. 147 is on the same border of the batholith -several miles farther northwest. The granite mass on the right is a -small outlier of the main batholith looking south. The limestone is -Cretaceous. See Appendix C for locations." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 146—Deformative effects on limestone strata of the -granite intrusion on the southwestern border of the Vilcapampa batholith -above Chuquibambilla. <a href="#fig_147">Fig. 147</a> is on the same border of the batholith -several miles farther northwest. The granite mass on the right is a -small outlier of the main batholith looking south. The limestone is -Cretaceous. See Appendix C for locations.</p> -</div> - -<p>These smaller intrusions are remarkable in that they appear to have been -attended by little alteration of either invading or invaded rock, though -the granites were observed to become distinctly more acid in the contact -zone. Space was made for them by displacing the sedimentary cover and by -a marked shortening of the sedimentary rim through such structures as -overthrust faults and folds. The contact is observable in a highly -metamorphosed belt about twenty feet wide, and for several hundred feet -more the granite has absorbed the limestone in small amounts with the -production of new minerals and the development of a distinctly lighter -color. The deformative effects of the batholithic invasion are shown in -their gross details in Figs. <a href="#fig_141">141</a>, <a href="#fig_142">142</a>, and <a href="#fig_146">146</a>; the finer details of -structure are represented in <a href="#fig_147">147</a> , which is drawn from a measured -outcrop above Chuquibambilla.</p> - -<p>It will be seen that we have here more than a mere crinkling,<a name="page_222" id="page_222"></a> such as -the mica schists of the Cordillera Vilcapampa display. The diversified -sedimentary series is folded and faulted on a large scale with broad -structural undulations visible for miles along the abrupt valley walls. -Here and there, however, the strata become weaker generally through the -thinning of the beds and the more rapid alternation of hard and soft -layers, and for short distances they have absorbed notable amounts of -the stresses induced by the igneous intrusions. In such places not only -the structure but the composition of the rock shows the effects of the -intrusion. Certain shales in the section are carbonaceous and in all -observed cases the organic matter has been transformed to anthracite, a -condition generally associated with a certain amount of minute mashing -and a cementation of both limestone and sandstone.</p> - -<p><a name="fig_147" id="fig_147"></a></p> - -<div class="figleft" style="width: 217px;"> -<a href="images/ill_page_222_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_222_sml.jpg" width="117" height="59" alt="Fig. 147—Overthrust folds in detail on the southwestern -border of the Vilcapampa batholith near Chuquibambilla. The section is -fifteen feet high. Elevation, 13,100 feet (4,000 m.). For comparison -with the structural effects of the Vilcapampa intrusion on the northeast -see Fig. 142." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 147—Overthrust folds in detail on the southwestern -border of the Vilcapampa batholith near Chuquibambilla. The section is -fifteen feet high. Elevation, 13,100 feet (4,000 m.). For comparison -with the structural effects of the Vilcapampa intrusion on the northeast -see <a href="#fig_142">Fig. 142</a>.</p> -</div> - -<p>The granite becomes notably darker on approach to the northeastern -contact near Colpani; the proportion of ferro-magnesian minerals in some -cases is so large as to give a distinctly black color in sharp contrast -to the nearly white granite typical of the central portion of the mass. -Large masses of shale foundered in the invading magma, and upon fusion -gave rise to huge black masses impregnated with quartz and in places -smeared or injected with granite magma. Everywhere the granite is marked -by numbers of black masses which appear at first sight to be -aggregations of dark minerals normal to the granite and due to -differentiation processes at the time of crystallization. It is, -however, noteworthy that these increase rapidly in number on approach to -the contact, until in the last half-mile they appear to grade into the -shale inclusions. It may, therefore, be doubted that they are -aggregations. From their universal distribution, their uniform -character, and their marked increase in numbers on approach<a name="page_223" id="page_223"></a> to lateral -contacts, it may reasonably be inferred that they represent foundered -masses of country rock. Those distant from present contacts are in -almost all cases from a few inches to a foot in diameter, while on -approach to lateral contacts they are in places ten to twenty feet in -width, as if the smaller areas represented the last remnants of large -inclusions engulfed in the magma near the upper or roof contact. They -are so thoroughly injected with silica and also with typical granite -magma as to make their reference to the country rock less secure on -petrographical than on purely distributional grounds.</p> - -<p>A parallel line of evidence relates to the distribution of complementary -dikes throughout the granite. In the main mass of the batholith the -dikes are rather evenly distributed as to kind with a slight -preponderance of the dark-colored group. Near the contact, however, -aplitic dikes cease altogether and great numbers of melanocratic dikes -appear. It may be inferred that we have in this pronounced condition -suggestions of strong influence upon the final processes of invasion and -cooling of the granite magma, on the part of the country rock detached -and absorbed by the invading mass. It might be supposed that the -indicated change in the character of the complementary dikes could be -ascribed to possible differentiation of the granite magma whereby a -darker facies would be developed toward the Colpani contact. It has, -however, been pointed out already that the darkening of the granite in -this direction is intimately related to a marked increase in the number -of inclusions, leaving little doubt that the thorough digestion of the -smaller masses of detached shales is responsible for the marked increase -in the number and variety of the ferro-magnesian and special contact -minerals.</p> - -<p>Upon the southwestern border of the batholith the number of aplitic -dikes greatly increases. They form prominent features, not only of the -granite, but also of the schists, adding greatly to the strong contrast -between the schist of the border zone and that outside the zone of -metamorphism. In places in the border schists, these are so numerous -that one may count up to twenty in a single view, and they range in size -from a few inches to ten<a name="page_224" id="page_224"></a> or fifteen feet. The greater fissility of the -schists as contrasted with the shales on the opposite or eastern margin -of the batholith caused them to be relatively much more passive in -relation to the granite magma. They were not so much torn off and -incorporated in the magma, as they were thoroughly injected and -metamorphosed. Added to this is the fact that they are petrographically -more closely allied to the granite than are the shales upon the -northeastern contact.<a name="page_225" id="page_225"></a></p> - -<h3><a name="CHAPTER_XIV" id="CHAPTER_XIV"></a>CHAPTER XIV<br /><br /> -THE COASTAL TERRACES</h3> - -<p>A<small>LONG</small> the entire coast of Peru are upraised and dissected terraces of -marine origin. They extend from sea level to 1,500 feet above it, and -are best displayed north of Mollendo and in the desert south of Payta. -The following discussion relates to that portion of the coast between -Mollendo and Camaná.</p> - -<p>At the time of the development of the coastal terraces the land was in a -state of temporary equilibrium, for the terraces were cut to a mature -stage as indicated by the following facts: (1) the terraces have great -width—from one to five and more miles; (2) their inner border is -straight, or, where curves exist, they are broad and regular; (3) the -terrace tops are planed off smoothly so that they now have an even -gradient and an almost total absence of rock stacks or unreduced spurs; -(4) the mature slopes of the Coast Range, strikingly uniform in gradient -and stage of development (<a href="#fig_148">Fig. 148</a>), are perfectly organized with -respect to the inner edge of the terrace. They descend gradually to the -terrace margin, showing that they were graded with respect to sea level -when the sea stood at the inner edge of the highest terrace.</p> - -<p>From the composition and even distribution of the thick-bedded Tertiary -deposits of the desert east of the Coast Range, it is concluded that the -precipitation of Tertiary time was greater than that of today (see p. -261). Therefore, if the present major streams reach the sea, it may also -be concluded that those of an earlier period reached the sea, provided -the topography indicates the perfect adjustment of streams to structure. -Lacustrine sediments are absent throughout the Tertiary section. Such -through-flowing streams, discharging on a stable coast, would also have -mature valleys as a consequence of long uninterrupted erosion at a fixed -level. The Majes river must have cut through the Coast Range<a name="page_226" id="page_226"></a> at Camaná -then as now. Likewise the Vitor at Quilca must have cut straight across -the Coast Range. An examination of the surface leading down from the -Coast Range to the upper edge of these valleys fully confirms this -deduction. Flowing and well-graded slopes descend to the brink of the -inner valley in each case, where they give way to the gorge walls that -continue the descent to the valley floor.</p> - -<p>Confirmatory evidence is found in the wide Majes Valley at Cantas and -Aplao. (See the Aplao Quadrangle for details.) Though the observer is -first impressed with the depth of the valley, its width is more -impressive still. It is also clear that two periods of erosion are -represented on its walls. Above Aplao the valley walls swing off to the -west in a great embayment quite inexplicable on structural grounds; in -fact the floor of the embayment is developed across the structure, which -is here more disordered than usual. The same is true below Cantas, as -seen from the trail, which drops over two scarps to get to the valley -floor. The upper, widely opened valley is correlated with the latter -part of the period in which were formed the mature terraces of the coast -and the mature slopes bordering the larger valleys where they cross the -Coast Range.</p> - -<p>After its mature development the well-graded marine terrace was upraised -and dissected. The deepest and broadest incisions in it were made where -the largest streams crossed it. Shallower and narrower valleys were -formed where the smaller streams that headed in the Coast Range flowed -across it. Their depth and breadth was in general proportional to the -height of that part of the Coast Range in which their headwaters lay and -to the size of their catchment basins.</p> - -<p>When the dissection of the terrace had progressed to the point where -about one-third of it had been destroyed, there came depression and the -deposition of Pliocene or early Pleistocene sands, gravels, and local -clay beds. Everywhere the valleys were partly or wholly filled and over -broad stretches, as in the vicinity of stream mouths and upon lower -portions of the terrace, extensive deposits were laid down. The largest -deposits lie several <a name="page_227" id="page_227"></a>hours’ ride south of Camaná, where locally they -attain a thickness of several hundred feet. Their upper surface was well -graded and they show a prolonged period of deposition in which the -former coastal terrace was all but concealed.</p> - -<p><a name="fig_148" id="fig_148"></a></p> -<p><a name="fig_149" id="fig_149"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_226a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_226a_sml.jpg" width="212" height="326" alt="Fig. 148—The Coast Range between Mollendo and Arequipa -at the end of June, 1911. There is practically no grass and only a few -dry shrubs. The fine network over the hill slopes is composed of -interlacing cattle tracks. The cattle roam over these hills after the -rains which come at long intervals. (See page 141 for description of the -rains and the transformations they effect. For example, in October, -1911, these hills were covered with grass.)" /></a> -<br /> - -<p class="caption"><span class="smcap">Fig</span>. 148—The Coast Range between Mollendo and Arequipa -at the end of June, 1911. There is practically no grass and only a few -dry shrubs. The fine network over the hill slopes is composed of -interlacing cattle tracks. The cattle roam over these hills after the -rains which come at long intervals. (See <a href="#page_141">page 141</a> for description of the -rains and the transformations they effect. For example, in October, -1911, these hills were covered with grass.)</p> - -<p class="caption"><span class="smcap">Fig. 149</span>—The great marine terrace at Mollendo. See <a href="#fig_150">Fig. -150</a> for profile.</p> -</div> - -<p>The uplift of the coast terrace and its subsequent dissection bring the -physical history down to the present. The uplift was not uniform; three -notches in the terrace show more faintly upon the granite-gneiss where -the buried rock terrace has been swept clean again, more strongly upon -the softer superimposed sands. They lie below the 700-foot contour and -are insignificant in appearance beside the slopes of the Coast Range or -the ragged bluff of the present coast.</p> - -<p>The effect of the last uplift of the coast was to impel the Majes River -again to cut down its lower course nearly to sea level. The Pliocene -terrace deposits are here entirely removed over an area several leagues -wide. In their place an extensive delta and alluvial fan have been -formed. At first the river undoubtedly cut down to base level at its -mouth and deposited the cut material on the sea floor, now shoal, for a -considerable distance from shore. We should still find the river in that -position had other agents not intervened. But in the Pleistocene a great -quantity of waste was swept into the Majes Valley, whereupon aggradation -began; and in the middle and lower valley it has continued down to the -present.</p> - -<p><a name="fig_150" id="fig_150"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_227_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_227_sml.jpg" width="333" height="46" alt="Fig. 150—Profile of the coastal terraces at Mollendo. At -1, in a tributary gorge, fossiliferous clay occurs at 800 feet elevation -above the sea. At 2 is a characteristic change of profile marking a drop -from a higher to a lower terrace. On the extreme left is the highest -terrace, just under 1,500 feet (460 m.)." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 150—Profile of the coastal terraces at Mollendo. At -1, in a tributary gorge, fossiliferous clay occurs at 800 feet elevation -above the sea. At 2 is a characteristic change of profile marking a drop -from a higher to a lower terrace. On the extreme left is the highest -terrace, just under 1,500 feet (460 m.).</p> -</div> - -<p><a name="page_228" id="page_228"></a></p> - -<p><a name="fig_151" id="fig_151"></a></p> - -<p><a name="fig_152" id="fig_152"></a></p> - -<p><a name="fig_153" id="fig_153"></a></p> - -<p><a name="fig_154" id="fig_154"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_228_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_228_sml.jpg" width="218" height="325" alt="Figs. 151-154—These four diagrams represent the physical -history and the corresponding physiographic development of the coastal -region of Peru between Camaná and Mollendo. The sedimentary beds in the -background of the first diagram are hypothetical and are supposed to -correspond to the quartzites of the Majes Valley at Aplao." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>s. 151-154—These four diagrams represent the physical -history and the corresponding physiographic development of the coastal -region of Peru between Camaná and Mollendo. The sedimentary beds in the -background of the first diagram are hypothetical and are supposed to -correspond to the quartzites of the Majes Valley at Aplao.</p> -</div> - -<p><a name="page_229" id="page_229"></a></p> - -<p>The effect has been not only the general aggradation of the valley -floor, but also the development of a combined delta and superimposed -alluvial fan at the valley mouth. The seaward extension of the delta has -been hastened by the gradation of the shore between the bounding -headlands, thus giving rise to marine marshes in which every particle of -contributed waste is firmly held. The plain of Camaná, therefore, -includes parts of each of the following: a delta, a superposed alluvial -fan, a salt-water marsh, a fresh-water marsh, a series of beaches, small -amounts of piedmont fringe at the foot of Pliocene deposits once trimmed -by the river and by waves, and extensive tracts of indefinite fill. (See -the Camaná Quadrangle for details.)</p> - -<p>With the coastal conditions now before us it will be possible to attempt -a correlation between the erosion features and the deposits of the coast -and those of the interior. An understanding of the comparisons will be -facilitated by the use of diagrams, Figs. 151-154, and by a series of -concise summary statements. From the relations of the figure it appears -that:</p> - -<p>1. The Tertiary deposits bordering the Majes Valley east of the Coast -Range were in process of deposition when the sea planed the coastal -terrace (<a href="#fig_151">Fig. 151</a>).</p> - -<p>2. A broad mature marine terrace without stacks or sharply alternating -spurs and reëntrants (though the rock is a very resistant granite) is -correlated with the mature grades of the Coast Range, with which they -are integrated and with the mature profiles of the main Cordillera.</p> - -<p>3. Such a high degree of topographic organization requires the -dissection in the <i>late</i> stages of the erosion cycle of at least the -inner or eastern border of the piedmont deposits of the desert, largely -accumulated during the <i>early</i> stages of the cycle.</p> - -<p>4. Since the graded slopes of the Coast Range on the one side descend to -a former shore whose elevation is now but 1,500 feet above sea level, -and since only ten to twenty miles inland on the other side of the -range, the same kind of slope extends beneath Tertiary deposits 4,000 -feet above sea level, it appears that aggradation of the outer (or -western) part of the Tertiary deposits<a name="page_230" id="page_230"></a> on the eastern border of the -Coast Range continued down to the end of the cycle of erosion, though</p> - -<p>5. There must have been an outlet to the sea, since, as we have already -seen, the water supply of the Tertiary was greater than that of today -and the present streams reach the sea. Moreover, the mature upper slopes -and the steep lower slopes of the large valleys make a pronounced -topographic unconformity, showing two cycles of valley development.</p> - -<p>6. Upon uplift of the coast and dissection of the marine terraces at the -foot of the Coast Range, the streams cut deep trenches on the floors of -their former valleys (<a href="#fig_152">Fig. 152</a>) and removed (a) large portions of the -coast terrace, and (b) large portions of the Tertiary deposits east of -the Coast Range.</p> - -<p>7. Depression of the coastal terrace and its partial burial meant the -drowning of the lower Majes Valley and its partial filling with marine -and later with terrestrial deposits. It also brought about the partial -filling by stream aggradation of the middle portion of the valley, -causing the valley fill to abut sharply against the steep valley walls. -(See <a href="#fig_155">155</a> .)</p> - -<p>8. Uplift and dissection of both the terrace and its overlying sediments -would be accompanied by dissection of the former valley fill, provided -that the waste supply was not increased and that the uplift was regional -and approximately equal throughout—not a bowing up of the coast on the -one hand, or an excessive bowing up of the mountains on the other. But -the waste supply has not remained constant, and the uplift has been -greater in the Cordillera than on the coast. Let us proceed to the proof -of these two conclusions, since upon them depends the interpretation of -the later physical history of the coastal valleys.</p> - -<p><a name="fig_155" id="fig_155"></a></p> -<p><a name="fig_156" id="fig_156"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_230a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_230a_sml.jpg" width="316" height="211" alt="Fig. 155—Steep walls in the Majes Valley below Cantas -and the abrupt termination against them of a deep alluvial fill." /></a> -<br /> - -<table border="0" cellpadding="5" cellspacing="0" summary=""> -<tr valign="top"><td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 155—Steep walls in the Majes Valley below Cantas -and the abrupt termination against them of a deep alluvial fill.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig. 156</span>—Canyon of the Majes River through the Coast -Range north of Camaná. The rock is a granite-gneiss capped by rather -flat-lying sedimentaries.</p></td></tr></table> - -</div> - -<p>It is known that the Pleistocene was a time of augmented waste delivery. -At the head of the broadly opened Majes Valley there was deposited a -huge mass of extremely coarse waste several hundred feet deep and -several miles long. Forward from it, interstratified with its outer -margin, and continuing the same alluvial grade, is a still greater mass -of finer material which descends to lower levels. The fine material is -deposited on the floor<a name="page_231" id="page_231"></a> of a valley cut into Tertiary strata, hence it -is younger than the Tertiary. It is now, and has been for some time -past, in process of dissection, hence it was not formed under present -conditions of climate and relief. It is confidently assigned to the -Pleistocene, since this is definitely known to have been a time of -greater precipitation and waste removal on the mountains, and deposition -on the plains and the floors of mountain valleys. Such a conclusion -appears, even on general grounds, to be but a shade less reliable than -if we were able to find in the upper Majes Valley, as in so many other -Andean valleys, similar alluvial deposits interlocked with glacial -moraines and valley trains.</p> - -<p>In regard to the second consideration—the upbowing of the -Cordillera—it may be noted that the valley and slope profiles of the -main Cordillera shown on p. <a href="#page_191">191</a>, when extended toward the margin of the -mountain belt, lie nearly a mile above the level of the sea on the west -and the Amazon plains on the east. The evidence of regional bowing thus -afforded is checked by the depths of the mountain valleys and the stream -profiles in them. The streams are now sunk from one to three thousand -feet below their former level. Even in the case of three thousand feet -of erosion the stream profiles are still ungraded, the streams -themselves are almost torrential, and from one thousand to three -thousand feet of vertical cutting must still be accomplished before the -profiles will be as gentle and regular as those of the preceding cycle -of erosion, in which were formed the mature slopes now lying high above -the valley floors.</p> - -<p>Further evidence of bowing is afforded by the attitude of the Tertiary -strata themselves, more highly inclined in the case of the older -Tertiary, less highly inclined in the case of the younger Tertiary. It -is noteworthy that the gradient of the present valley floor is -distinctly less than that of the least highly inclined strata. This is -true even where aggradation is now just able to continue, as near the -nodal point of the valley, above Aplao, where cutting ceases and -aggradation begins. (See the Aplao Quadrangle for change of function on -the part of the stream a half mile above Cosos). Such a progressive -steepening of<a name="page_232" id="page_232"></a> gradients in the direction of the oldest deposits, shows -very clearly a corresponding progression in the growth of the Andes at -intervals throughout the Tertiary.</p> - -<p>Thus we have aggradation in the Tertiary at the foot of the growing -Andes; aggradation in the Pliocene or early Pleistocene on the floor of -a deep valley cut in earlier deposits; aggradation in the glacial epoch; -and aggradation now in progress. Basin deposits within the borders of -the Peruvian Andes are relatively rare. The profound erosion implied by -the development, first of a mature topography across this great -Cordillera, and second of many deep canyons, calls for deposition on an -equally great scale on the mountain borders. The deposits of the western -border are a mile thick, but they are confined to a narrow zone between -the Coast Range and the Cordillera. Whatever material is swept beyond -the immediate coast is deposited in deep ocean water, for the bottom -falls off rapidly. The deposits of the eastern border of the Andes are -carried far out over the Amazon lowland. Those of earlier geologic -periods were largely confined to the mountain border, where they are now -upturned to form the front range of the Andes. The Tertiary deposits of -the eastern border are less restricted, though they appear to have -gathered chiefly in a belt from fifty to one hundred miles wide.</p> - -<p>The deposits of the western border were laid down by short streams -rising on a divide only 100 to 200 miles from the Pacific. Furthermore, -they drain the dry leeward slopes of the Andes. The deposits of the wet -eastern border were made by far larger streams that carry the waste of -nearly the whole Cordillera. Their shoaling effect upon the Amazon -depression must have been a large factor in its steady growth from an -inland sea to a river lowland.<a name="page_233" id="page_233"></a></p> - -<h3><a name="CHAPTER_XV" id="CHAPTER_XV"></a>CHAPTER XV<br /><br /> -PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT</h3> - -<h4>GENERAL FEATURES</h4> - -<p>In the preceding chapter we employed geologic facts in the determination -of the age of the principal topographic forms. These facts require -further discussion in connection with their closest physiographic allies -if we wish to show how the topography of today originated. There are -many topographic details that have a fundamental relation to structure; -indeed, without a somewhat detailed knowledge of geology only the -broader and more general features of the landscape can be interpreted. -In this chapter we shall therefore refer not to the scenic features as -in a purely topographic description, but to the rock structure and the -fossils. A complete and technical geologic discussion is not desirable, -first, because it should be based upon much more detailed geologic field -work, and second because after all our main purpose is not to discuss -the geologic features <i>per se</i>, but the physiographic background which -the geologic facts afford. I make this preliminary observation partly to -indicate the point of view and partly to emphasize the necessity, in a -broad, geographic study, for the reconstruction of the landscapes of the -past.</p> - -<p>The two dominating ranges of the Peruvian Andes, called the Maritime -Cordillera and the Cordillera Vilcapampa, are composed of igneous -rock—the one volcanic lava, the other intrusive granite. The chief rock -belts of the Andes of southern Peru are shown in <a href="#fig_157">157</a> . The Maritime -Cordillera is bordered on the west by Tertiary strata that rest -unconformably upon Palaeozoic quartzites. It is bordered on the east by -Cretaceous limestones that grade downward into sandstones, shales, and -basal conglomerates. At some places the Cretaceous deposits rest upon -old schists, at others upon Carboniferous limestones and related<a name="page_234" id="page_234"></a> -strata, upon small granite intrusives and upon old and greatly altered -volcanic rock.</p> - -<p>The Cordillera Vilcapampa has an axis of granitic rock which was thrust -upward through schists that now border it on the west and slates that -now border it on the east. The slate series forms a broad belt which -terminates near the eastern border of the Andes, where the mountains -break down abruptly to the river plains of the Amazon Basin. The -immediate border on the east is formed of vertical Carboniferous -limestones. The narrow foothill belt is composed of Tertiary sandstones -that grade into loose sands and conglomerates. The inclined Tertiary -strata were leveled by erosion and in part overlain by coarse and now -dissected river gravels, probably of Pleistocene age. Well east of the -main border are low ranges that have never been described. They could -not be reached by the present expedition on account of lack of time. On -the extreme western border of that portion of the Peruvian Andes herein -described, there is a second distinct border chain, the Coast Range. It -is composed of granite and once had considerable relief, but erosion has -reduced its former bold forms to gentle slopes and graded profiles.</p> - -<p>The continued and extreme growth of the Andes in later geologic periods -has greatly favored structural and physiographic studies. Successive -uplifts have raised earlier deposits once buried on the mountain flanks -and erosion has opened canyons on whose walls and floors are the clearly -exposed records of the past. In addition there have been igneous -intrusions of great extent that have thrust aside and upturned the -invaded strata exposing still further the internal structures of the -mountains. From sections thus revealed it is possible to outline the -chief events in the history of the Peruvian Andes, though the outline is -still necessarily broad and general because based on rapid -reconnaissance. However, it shows clearly that the landscape of the -present represents but a temporary stage in the evolution of a great -mountain belt. At the dawn of geologic history there were chains of -mountains where the Andes now stand. They were swept away and even their -roots deeply submerged under invading seas. Re<a name="page_235" id="page_235"></a><a name="page_236" id="page_236"></a>peated uplifts of the -earth’s crust reformed the ancient chains or created new ones out of the -rock waste derived from them. Each new set of forms, therefore, exhibits -some features transmitted from the past. Indeed, the landscape of today -is like the human race—inheriting much of its character from past -generations. For this reason the philosophical study of topographic -forms requires at least a broad knowledge of related geologic -structures.</p> - -<p><a name="fig_157" id="fig_157"></a></p> - -<div class="figleft" style="width: 150px;"> -<a href="images/ill_page_235_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_235_sml.jpg" width="101" height="333" alt="Fig. 157—Outline sketch showing the principal rock belts -of Peru along the seventy-third meridian. They are: 1, Pleistocene and -Recent gravels and sands, the former partly indurated and slightly -deformed, with the degree of deformation increasing toward the mountain -border (south). 2, Tertiary sandstones, inclined from 15° to 30° -toward the north and unconformably overlain by Pleistocene gravels. 3, -fossil-bearing Carboniferous limestones with vertical dip. 4, -non-fossiliferous slates, shales, and slaty schists (Silurian) with -great variation in degree of induration and in type of structure. South -of the parallel of 13° is a belt of Carboniferous limestones and -sandstones bordering (5), the granite axis of the Cordillera -Vilcapampa. For its structural relations to the Cordillera see Figs. 141 -and 142. 6, old and greatly disturbed volcanic agglomerates, tuffs and -porphyries, and quartzitic schists and granite-gneiss. 7, principally -Carboniferous limestones north of the axis of the Central Ranges and -Cretaceous limestones south of it. Local granite batholiths in the axis -of the Central Ranges. 8, quartzites and slates predominating with -thin limestones locally. South of 8 is a belt of shale, sandstone, and -limestone with a basement quartzite appearing on the valley floors. 9, -a portion of the great volcanic field of the Central Andes and -characteristically developed in the Western or Maritime Cordillera, -throughout northern Chile, western Bolivia, and Peru. At Cotahuasi (see -also Fig. 20) Cretaceous limestones appear beneath the lavas. 10, -Tertiary sandstones of the coastal desert with a basement of old -volcanics and quartzites appearing on the valley walls. The valley floor -is aggraded with Pleistocene and Recent alluvium. 11, granite-gneiss -of the Coast Range. 12, late Tertiary or Pleistocene sands and gravels -deposited on broad coastal terraces. For rock structure and character -see the other figures in this chapter. For a brief designation of index -fossils and related forms see Appendix B. For the names of the drainage -lines and the locations of the principal towns see Figs. 20 and 204." /></a> -</div> -<p class="caption"><span class="smcap">Fig</span>. 157—Outline sketch showing the principal rock belts -of Peru along the seventy-third meridian. They are: 1, Pleistocene and -Recent gravels and sands, the former partly indurated and slightly -deformed, with the degree of deformation increasing toward the mountain -border (south). 2, Tertiary sandstones, inclined from 15° to 30° -toward the north and unconformably overlain by Pleistocene gravels. 3, -fossil-bearing Carboniferous limestones with vertical dip. 4, -non-fossiliferous slates, shales, and slaty schists (Silurian) with -great variation in degree of induration and in type of structure. South -of the parallel of 13° is a belt of Carboniferous limestones and -sandstones bordering (5), the granite axis of the Cordillera -Vilcapampa. For its structural relations to the Cordillera see <a href="#fig_141">Figs. 141</a> -and <a href="#fig_142">142</a>. 6, old and greatly disturbed volcanic agglomerates, tuffs and -porphyries, and quartzitic schists and granite-gneiss. 7, principally -Carboniferous limestones north of the axis of the Central Ranges and -Cretaceous limestones south of it. Local granite batholiths in the axis -of the Central Ranges. 8, quartzites and slates predominating with -thin limestones locally. South of 8 is a belt of shale, sandstone, and -limestone with a basement quartzite appearing on the valley floors. 9, -a portion of the great volcanic field of the Central Andes and -characteristically developed in the Western or Maritime Cordillera, -throughout northern Chile, western Bolivia, and Peru. At Cotahuasi (see -also <a href="#fig_20">Fig. 20</a>) Cretaceous limestones appear beneath the lavas. 10, -Tertiary sandstones of the coastal desert with a basement of old -volcanics and quartzites appearing on the valley walls. The valley floor -is aggraded with Pleistocene and Recent alluvium. 11, granite-gneiss -of the Coast Range. 12, late Tertiary or Pleistocene sands and gravels -deposited on broad coastal terraces. For rock structure and character -see the other figures in this chapter. For a brief designation of index -fossils and related forms see <a href="#APPENDIX_B">Appendix B</a>. For the names of the drainage -lines and the locations of the principal towns see Figs. <a href="#fig_20">20</a> and <a href="#fig_204">204</a>.</p> - -<h4>SCHISTS AND SILURIAN SLATES<span style="font-size:100%;"> -<a name="FNanchor_50_50" id="FNanchor_50_50"></a><a href="#Footnote_50_50" class="fnanchor">[50]</a> -</span></h4> - -<p>The oldest series of rocks along the seventy-third meridian of Peru -extends eastward from the Vilcapampa batholith nearly to the border of -the Cordillera, <a href="#fig_157">157</a> . It consists of (1) a great mass of slates and -shales with remarkable uniformity of composition and structure over -great areas, and (2) older schists and siliceous members in restricted -belts. They are everywhere thoroughly jointed; near the batholith they -are also mineralized and altered from their original condition; in a few -places they have been intruded with dikes and other form of igneous -rock.</p> - -<p>The slates and shales underlie known Carboniferous strata on their -eastern border and appear to be a physical continuation of the -fossiliferous slates of Bolivia; hence they are provisionally referred -to the Silurian, though they may possibly be Devonian. Certainly the -known Devonian exceeds in extent the known Silurian in the Central Andes -but its lithological character is generally quite unlike the character -of the slates here referred to the Silurian. The schists are of great -but unknown age. They are unconformably overlain by known Carboniferous -at Puquiura in the Vilcapampa Valley (<a href="#fig_158">Fig. 158</a>), and near Chuquibambilla -on the opposite side of the Cordillera Vilcapampa. The deeply weathered -fissile mica schists east of Pasaje (see <a href="#APPENDIX_C">Appendix C</a> for all locations) -are also unconformably overlain by conglomerate and sandstone of -Carboniferous age. While the schists vary considerably in lithological -appearance and also in structure, they are everywhere the lowest rocks -in the series and may with confidence<a name="page_237" id="page_237"></a> be referred to the early -Palaeozoic, while some of them may date from the Proteriozoic.</p> - -<p><a name="fig_158" id="fig_158"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_237_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_237_sml.jpg" width="211" height="87" alt="Fig. 158—Geologic sketch map of the lower Urubamba -Valley. A single traverse was made along the valley, hence the -boundaries are not accurate in detail. They were sketched in along a few -lateral traverses and also inferred from the topography. The country -rock is schist and the granite intruded in it is an arm of the main -granite mass that constitutes the axis of the Cordillera Vilcapampa. The -structure and to some degree the extent of the sandstone on the left are -represented in Figs. 141 and 142." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 158—Geologic sketch map of the lower Urubamba -Valley. A single traverse was made along the valley, hence the -boundaries are not accurate in detail. They were sketched in along a few -lateral traverses and also inferred from the topography. The country -rock is schist and the granite intruded in it is an arm of the main -granite mass that constitutes the axis of the Cordillera Vilcapampa. The -structure and to some degree the extent of the sandstone on the left are -represented in Figs. <a href="#fig_141">141</a> and <a href="#fig_142">142</a>.</p> -</div> - -<p>The Silurian beds are composed of shale, sandstone, shaly sandstone, -limestone, and slate with some slaty schist, among which the shales are -predominent and the limestones least important. Near their contact with -the granite the slate series is composed of alternating beds of -sandstone and shale arranged in beds from one to three feet thick. At -Santa Ana they become more fissile and slaty in character and in several -places are quarried and used for roofing. At Rosalina they consist of -almost uniform beds of shale so soft and so minutely and thoroughly -jointed as to weather easily. Under prolonged erosion they have, -therefore, given rise to a well-rounded and soft-featured landscape. -Farther down the Urubamba Valley they again take on the character of -alternating beds of sandstone and shale from a few feet to fifteen and -more feet thick. In places the metamorphism of the series has been -carried further—the shales have become slates and the sandstones have -been altered to extremely resistant quartzites. The result is again -clearly shown in the topography of the valley wall which becomes bold, -inclosing the river<a name="page_238" id="page_238"></a> in narrow “pongos†or canyons filled with huge -bowlders and dangerous rapids. The hills become mountains, ledges -appear, and even the heavy forest cover fails to smooth out the natural -ruggedness of the landscape.</p> - -<p>It is only upon their eastern border that the Silurian series includes -calcareous beds, and all of these lie within a few thousand yards of the -contact with the Carboniferous limestones and shales. At first they are -thin paper-like layers; nearer the top they are a few inches wide and -finally attain a thickness of ten or twelve feet. The available -limestone outcrops were rigorously examined for fossils but none were -found, although they are lavishly distributed throughout the younger -Carboniferous beds just above them. It is also remarkable that though -the Silurian age of these beds is reasonably inferred they are not -separated from the Carboniferous by an unconformity, at least we could -find none in this locality. The later beds disconformably overlie the -earlier beds, although the sharp differences in lithology and fossils -make it easy to locate the line of separation. The limestone beds of the -Silurian series are extremely compact and unfossiliferous. At least in -this region those of Carboniferous age are friable and the fossils -varied and abundant. The Silurian beds are everywhere strongly inclined -and throughout the eastern half or third of their outcrop in the -Urubamba Valley they are nearly vertical.</p> - -<p>In view of the enormous thickness of the repeated layers of shale and -sandstone this series is of great interest. Added importance attaches to -their occurrence in a long belt from the eastern edge of the Bolivian -highlands northward through Peru and possibly farther. From the fact -that their disturbance has been on broad lines over wide areas with -extreme metamorphism, they are to be separated from the older -mica-schists and the crumpled chlorite schists of Puquiura and Pasaje. -Further reasons for this distinction lie in their lithologic difference -and, to a more important degree, in the strong unconformity between the -Carboniferous and the schists in contrast to the disconformable -relations shown between the Carboniferous and Silurian fifty<a name="page_239" id="page_239"></a> miles away -at Pongo de Mainique. The mashing and crumpling that the schists have -experienced at Puquiura is so intense, that were they a part of the -Silurian series the latter should exhibit at least a slight unconformity -in relation to the Carboniferous limestones deposited upon them.</p> - -<p>If our interpretation of the relation of the schists to the slates and -shales be correct, we should have a mountain-making period introduced in -pre-Silurian time, affecting the accumulated sediments and bringing -about their metamorphism and crumpling on a large scale. From the -mountains and uplands thus created on the schists, sediments were washed -into adjacent waters and accumulated as even-bedded and extensive sheets -of sands and muds (the present slates, shales, quartzites, etc.). -Nowhere do the sediments of the slate series show a conglomeratic phase; -they are remarkably well-sorted and consist of material disposed with -great regularity. Though they are coarsest at the bottom the lower beds -do not show cross-bedding, ripple marking, or other signs of -shallow-water conditions. Toward the upper part of the series these -features, especially the ripple-marking, make their appearance. During -the deposition of the last third of the series, and again just before -the deposition of the limestone, the beds took on a predominantly -arenaceous character associated with ripple marks and cross-bedding -characteristic of shallow-water deposits.</p> - -<p>In the persistence of arenaceous sediments throughout the series and the -distribution of the ripple marks through the upper third of the beds, we -have a clear indication that the degree of shallowness was sufficient to -bring the bottom on which the sediments accumulated into the zone of -current action and possibly wave action. It is also worth considering -whether the currents involved were not of similar origin to those now a -part of the great counter-clockwise movements in the southern seas. If -so, their action would be peculiarly effective in the wide distribution -of the sediment derived from a land mass on the eastern edge of a -continental coast, since they would spread out the material to a greater -and greater degree as they flowed into more southerly<a name="page_240" id="page_240"></a> latitudes. Among -geologic agents a broad ocean current of relatively uniform flow would -produce the most uniform effects throughout a geologic period, in which -many thousand feet of clastic sediments were being accumulated. A -powerful ocean current would also work on flats (in contrast to the -gradient required by near-shore processes), and at the same time be of -such deep and steady flow as to result in neither ripple marks nor -cross-bedding.</p> - -<p>The increasing volume of shallow-water sediments of uniform character -near the end of the Silurian, indicates great crustal stability at a -level which brought about neither a marked gain nor loss of material to -the region. At any rate we have here no Devonian sediments, a -characteristic shared by almost all the great sedimentary formations of -Peru. At the beginning of the Carboniferous the water deepened, and -great heavy-bedded limestones appear with only thin shale partings -through a vertical distance of several hundreds of feet. The enormous -volume of Silurian sediments indicates the deep and prolonged erosion of -the land masses then existing, a conclusion further supported (1) by the -extensive development of the Silurian throughout Bolivia as well as -Peru, (2) by the entire absence of coarse material whether at the top or -bottom of the section, and (3) by the very limited extent of older rock -now exposed even after repeated and irregular uplift and deep -dissection. Indeed, from the latter very striking fact, it may be -reasonably argued that in a general way the relief of the country was -reduced to sea level at the close of the Silurian. Over the perfected -grades of that time there would then be afforded an opportunity for the -effective transportation of waste to the extreme limits of the land.</p> - -<p>Further evidence of the great reduction of surface during the Silurian -and Devonian is supplied by the extensive development of the -Carboniferous strata. Their outcrops are now scattered across the higher -portions of the Andean Cordillera and are prevailingly calcareous in -their upper portions. Upon the eastern border of the Silurian they -indicate marine conditions from the opening of the period, but at Pasaje -in the Apurimac Valley they<a name="page_241" id="page_241"></a> are marked by heavy beds of basal -conglomerate and sandstone, and an abundance of ripple marking and other -features associated with shallow-water and possibly near-shore -conditions.</p> - -<h4>CARBONIFEROUS</h4> - -<p>Carboniferous strata are distributed along the seventy-third meridian -and rival in extent the volcanic material that forms the western border -of the Andes. They range in character from basal conglomerates, -sandstones, and shales of limited development, to enormous beds of -extremely resistant blue limestone, in general well supplied with -fossils. On the eastern border of the Andes they are abruptly terminated -by a great fault, the continuation northward of the marginal fault -recognized in eastern Bolivia by Minchin<a name="FNanchor_51_51" id="FNanchor_51_51"></a><a href="#Footnote_51_51" class="fnanchor">[51]</a> and farther north by the -writer.<a name="FNanchor_52_52" id="FNanchor_52_52"></a><a href="#Footnote_52_52" class="fnanchor">[52]</a> Coarse red sandstones with conglomeratic phase abut sharply -and with moderate inclination against almost vertical sandstones and -limestones of Carboniferous age. The break between the vertical -limestones and the gently inclined sandstones is marked by a prominent -scarp nearly four thousand feet high (<a href="#fig_159">Fig. 159</a>), and the limestone -itself forms a high ridge through which the Urubamba has cut a narrow -gateway, the celebrated Pongo de Mainique.</p> - -<p><a name="fig_159" id="fig_159"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_241_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_241_sml.jpg" width="211" height="51" alt="Fig. 159—Topographic and structural section at the -northeastern border of the Peruvian Andes. The slates are probably -Silurian, the fossiliferous limestones are known Carboniferous, and the -sandstones are Tertiary grading up to Pleistocene." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 159—Topographic and structural section at the -northeastern border of the Peruvian Andes. The slates are probably -Silurian, the fossiliferous limestones are known Carboniferous, and the -sandstones are Tertiary grading up to Pleistocene.</p> -</div> - -<p>At Pasaje, on the western side of the Apurimac, the Carboniferous again -appears resting upon the old schists described on p. <a href="#page_236">236</a>. It is steeply -upturned, in places vertical, is highly conglomeratic, and in a belt a -half-mile wide it forms true badlands topography.<a name="page_242" id="page_242"></a> It is succeeded by -evenly bedded sandstones of fine and coarse composition in alternate -beds, then follow shales and sandstones and finally the enormous beds of -limestone that characterize the series. The structure is on the whole -relatively simple in this region, the character and attitude of the beds -indicating their accumulation in a nearly horizontal position. Since the -basal conglomerate contains only pebbles and stones derived from the -subjacent schists and does not contain granites like those in the -Cordillera Vilcapampa batholith on the east it is concluded that the -batholithic invasion was accompanied by the compression and tilting of -the Carboniferous beds and that the batholith itself is -post-Carboniferous. From the ridge summits above Huascatay and in the -deep valleys thereabouts the Carboniferous strata may be seen to extend -far toward the west, and also to have great extent north and south. -Because of their dissected, bare, and, therefore, well-exposed condition -they present exceptional opportunities for the study of Carboniferous -geology in central Peru.</p> - -<p><a name="fig_160" id="fig_160"></a></p> - -<div class="figleft" style="width: 155px;"> -<a href="images/ill_page_242_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_242_sml.jpg" width="105" height="57" alt="Fig. 160—The deformative effects of the granite -intrusion of the Cordillera Vilcapampa are here shown as transmitted -through ancient schists to the overlying conglomerates, sandstones, and -limestones of Carboniferous age, in the Apurimac Valley at Pasaje." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 160—The deformative effects of the granite -intrusion of the Cordillera Vilcapampa are here shown as transmitted -through ancient schists to the overlying conglomerates, sandstones, and -limestones of Carboniferous age, in the Apurimac Valley at Pasaje.</p> -</div> - -<p>Carboniferous strata again appear at Puquiura, Vilcapampa, and -Pampaconas. They are sharply upturned against the Vilcapampa batholith -and associated volcanic material, chiefly basalt, porphyry, and various -tuffs and related breccias. The Carboniferous beds are here more -arenaceous, consisting chiefly of alternating beds of sandstone and -shale. The lowermost beds, as at Pongo de Mainique, are dominantly -marine, fossiliferous limestone beds having a thickness estimated to be -over two miles.</p> - -<p>From Huascatay westward and southward the Carboniferous is in part -displaced by secondary batholiths of granite, in part cut off or crowded -aside by igneous intrusions of later date, and in still larger part -buried under great masses of Tertiary volcanic<a name="page_243" id="page_243"></a> material. Nevertheless, -it remains the dominating rock type over the whole stretch of country -from Huascatay to Huancarama. In the northwestern part of the Abancay -sheet its effect on the landscape may be observed in the knife-like -ridge extending from west to east just above Huambo. Above -Chuquibambilla it again outcrops, resting upon a thick resistant -quartzite of unknown age, <a href="#fig_162">162</a> . It is strongly developed about -Huadquirca and Antabamba and, still associated with a quartzite floor, -it finally disappears under the lavas of the great volcanic field on the -western border of the Andes. Figs. 141 and 142 show its relation to the -invading granite batholiths and <a href="#fig_162">162</a> shows further structural -features as developed about Antabamba where the great volcanic field of -the Maritime Cordillera begins.</p> - -<p><a name="fig_161" id="fig_161"></a></p> - -<div class="figright" style="width: 158px;"> -<a href="images/ill_page_243a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_243a_sml.jpg" width="108" height="51" alt="Fig. 161—Types of deformation north of Lambrama near -Sotospampa. A dark basaltic rock has invaded both granite-gneiss and -slate. Sills and dikes occur in great numbers. The topographic -depression in the profile is the Lambrama Valley. See the Lambrama -Quadrangle." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 161—Types of deformation north of Lambrama near -Sotospampa. A dark basaltic rock has invaded both granite-gneiss and -slate. Sills and dikes occur in great numbers. The topographic -depression in the profile is the Lambrama Valley. See the Lambrama -Quadrangle.</p> -</div> - -<p>Both the enormous thickness of the Carboniferous limestone series and -the absence of clastic members over great areas in the upper portion of -the series prove the widespread extent of the Carboniferous seas and -their former occurrence in large interlimestone tracts from which they -have since been eroded. At Puquiura they extend far over the schist, in -fact almost completely conceal it; at Pasaje they formerly covered the -mica-schists extensively, their erosion in both cases being conditioned -by the pronounced uplift and marginal deformation which accompanied the -development of the Vilcapampa batholith.</p> - -<p><a name="fig_162" id="fig_162"></a></p> - -<div class="figleft" style="width: 155px;"> -<a href="images/ill_page_243b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_243b_sml.jpg" width="105" height="53" alt="Fig. 162—Sketch sections at Antabamba to show (a) -deformed limestones on the upper edge of the geologic map, Fig. 163 A; -and (b) the structural relations of limestone and quartzite. See also -Fig. 163." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 162—Sketch sections at Antabamba to show (a) -deformed limestones on the upper edge of the geologic map, <a href="#fig_163">163</a> A; -and (b) the structural relations of limestone and quartzite. See also -<a href="#fig_163">Fig. 163</a>.</p> -</div> - -<p><a name="page_244" id="page_244"></a></p> - -<p>The degree of deformation of the Carboniferous sediments varies between -simple uplift through moderate folding and complex disturbances -resulting in nearly vertical attitudes. The simplest structures are -represented at Pasaje, where the uplift of the intruded schists, -marginal to the Vilcapampa batholith, has produced an enormous -monoclinal fold exposing the entire section from basal conglomerates and -sandstones to the thickest limestone. Above Chuquibambilla the -limestones have been uplifted and very gently folded by the invasion of -granite associated with the main batholith and several satellitic -batholiths of limited extent. A higher degree of complexity is shown at -Pampaconas (<a href="#fig_141">Fig. 141</a>), where the main monoclinal fold is traversed -almost at right angles by secondary folds of great amplitude. The -limestones are there carried to the limit of the winter snows almost at -the summit of the Cordillera. The crest of each secondary anticline -rises to form a group of conspicuous peaks and tabular ridges. Higher in -the section, as at Puquiura, the sandstones are thrown into a series of -huge anticlines and synclines, apparently by the marginal compression -brought about at the time of the intrusion of the granite core of the -range. At Pongo de Mainique the whole of the visible Carboniferous is -practically vertical, and is cut off by a great fault marking the abrupt -eastern border of the Cordillera.</p> - -<p><a name="fig_163" id="fig_163"></a></p> - -<div class="figleft" style="width: 106px;"> -<a href="images/ill_page_244_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_244_sml.jpg" width="106" height="38" alt="Fig. 163—Geologic sketch section to show the relation of -the volcanic flows of Fig. 164 to the sandstones and quartzites -beneath." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 163—Geologic sketch section to show the relation of -the volcanic flows of <a href="#fig_164">Fig. 164</a> to the sandstones and quartzites -beneath.</p> -</div> - -<p>It is noteworthy that the farther east the Carboniferous extends the -more dominantly marine it becomes, though marine beds of great thickness -constitute a large part of the series in whatever location. From -Huascatay westward the limestones become more and more argillaceous, and -finally give way altogether to an enormous thickness of shales, -sandstones, and thin conglomerates. These were observed to extend with -strong inclination westward out of the region studied and into and under -the volcanoes crowning the western border of the Cordillera. Along the -line of<a name="page_245" id="page_245"></a> traverse opportunity was not afforded for further study of this -aspect of the series, since our route led generally along the strike -rather than along the dip of the beds. It is interesting to note, -however, that these observations as to the increasing amounts of clastic -material in a westward direction were afterwards confirmed by Señor José -Bravo, the Director of the Bureau of Mines at Lima, who had found -Carboniferous land plants in shales at Pacasmayo, the only fossils of -their kind found in Peru. Formerly it had been supposed that non-marine -Carboniferous was not represented in Peru. From the varied nature of the -flora, the great thickness of the shales in which the specimens were -collected, and the fact that the dominantly marine Carboniferous -elsewhere in Peru is of great extent, it is concluded that the land upon -which the plants grew had a considerable area and probably extended far -west of the present coast line. Since its emergence it has passed -through several orogenic movements. These have resulted in the uplift of -the marine portion of the Carboniferous, while the terrestrial deposits -seem to have all but disappeared in the down-sunken blocks of the ocean -floor, west of the great fault developed along the margin of the -Cordillera. The following figures are graphic representations of this -hypothesis.</p> - -<p><a name="fig_164" id="fig_164"></a></p> - -<div class="figright" style="width: 156px;"> -<a href="images/ill_page_245_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_245_sml.jpg" width="106" height="169" alt="Fig. 164—Geologic sketch map and section, Antabamba -region. The Antabamba River has cut through almost the entire series of -bedded strata" /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 164—Geologic sketch map and section, Antabamba -region. The Antabamba River has cut through almost the entire series of -bedded strata.</p> -</div> - -<p><a name="fig_165" id="fig_165"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_246_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_246_sml.jpg" width="334" height="112" alt="Fig. 165—The upper diagram (A) represents the -hypothetical distribution of land and sea during the Carboniferous -Period, as inferred from the present distribution and character of -Carboniferous limestones and slates. The lower diagram (B) represents -the present relief. The dotted line at the left of the two diagrams -connects identical points. The fragmentation of the former continental -border is believed to have left only a small portion of a former coastal -chain and to have been contemporaneous with the development of ocean -abysses near the present shore." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 165—The upper diagram (A) represents the -hypothetical distribution of land and sea during the Carboniferous -Period, as inferred from the present distribution and character of -Carboniferous limestones and slates. The lower diagram (B) represents -the present relief. The dotted line at the left of the two diagrams -connects identical points. The fragmentation of the former continental -border is believed to have left only a small portion of a former coastal -chain and to have been contemporaneous with the development of ocean -abysses near the present shore.</p> -</div> - -<p>The wide distribution of the Carboniferous sediments and especially the -limestones, together with the uniformity of the fossil faunas, makes it -certain that the sea extended entirely across<a name="page_246" id="page_246"></a><a name="page_247" id="page_247"></a> the region now occupied -by the Andes. However, from the relation of the Carboniferous to the -basal schists, and the most conservative extension of the known -Carboniferous, it may be inferred that the Carboniferous sea did not -completely cover the entire area but was broken here and there by island -masses in the form of an elongated archipelago. The presence of land -plants in the Carboniferous of Pisco warrants the conclusion that a -second island mass, possibly an island chain parallel to the first, -extended along and west of the present shore.</p> - -<h4>CRETACEOUS</h4> - -<p>The Cretaceous formations are of very limited extent in the belt of -country under consideration, in spite of their generally wide -distribution in Peru. They are exposed distinctly only on the western -border of the Cordillera and in special relations. In the gorge of -Cotahuasi, over seven thousand feet deep, about two thousand feet of -Cretaceous limestones are exposed. The series includes only a very -resistant blue limestone and terminates abruptly along a well-marked and -highly irregular erosion surface covered by almost a mile of volcanic -material, chiefly lava flows. The character of the bottom of the section -is likewise unknown, since it lies apparently far below the present -level of erosion.</p> - -<p><a name="fig_166" id="fig_166"></a></p> - -<div class="figright" style="width: 156px;"> -<a href="images/ill_page_247_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_247_sml.jpg" width="106" height="129" alt="Fig. 166—Geologic sketch map and cross-section in the -Cotahuasi Canyon at Cotahuasi. With a slight gap this figure continues -Fig. 167 to the left. The section represents a spur of the main plateau -about 1,500 feet high in the center of the map." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 166—Geologic sketch map and cross-section in the -Cotahuasi Canyon at Cotahuasi. With a slight gap this figure continues -Fig. 167 to the left. The section represents a spur of the main plateau -about 1,500 feet high in the center of the map.</p> -</div> - -<p>The Cretaceous limestones of the Cotahuasi Canyon are everywhere greatly -and irregularly disturbed. Typical conditions are represented in the -maps and sections, Figs. 166 and 167. They are<a name="page_248" id="page_248"></a> penetrated and tilted by -igneous masses, apparently the feeders of the great lava sheets that -form the western summit of the Cordillera. From the restricted -development of the limestones along a western border zone it might be -inferred that they represent a very limited marine invasion. It is -certainly clear that great deformative movements were in progress from -at least late Palæozoic time since all the Palæozoic deposits are broken -abruptly down in this direction, and, except for such isolated -occurrences as the land Carboniferous at Pacasmayo, are not found -anywhere in the coastal region today. The Cretaceous is not only limited -within a relatively narrow shore zone, but also, like the Palæozoic, it -is broken down toward the west, not reappearing from beneath the -Tertiary cover of the desert region or upon the granite-gneisses that -form the foundation for all the known sedimentary strata of the -immediate coast.</p> - -<p><a name="fig_167" id="fig_167"></a></p> - -<div class="figleft" style="width: 154px;"> -<a href="images/ill_page_248_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_248_sml.jpg" width="104" height="109" alt="Fig. 167—Geologic sketch map and cross-section in the -Cotahuasi Canyon at Taurisma, above Cotahuasi. The relations of -limestone and lava flows in the center of the map and on a spur top near -the canyon floor. Thousands of feet of lava extend upward from the flows -that cap the limestone." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 167—Geologic sketch map and cross-section in the -Cotahuasi Canyon at Taurisma, above Cotahuasi. The relations of -limestone and lava flows in the center of the map and on a spur top near -the canyon floor. Thousands of feet of lava extend upward from the flows -that cap the limestone.</p> -</div> - -<p>From these considerations I think we have a strong suggestion of the -geologic date assignable to the development of the great fault that is -the most strongly marked structural and physiographic feature of the -west coast of South America. Since the development of this fault is so -intimately related to the origin of the Pacific Ocean basin its study is -of special importance. The points of chief interest may be summarized as -follows:</p> - -<p>(1) The character of the land Carboniferous implies a much greater -extent of the land than is now visible.</p> - -<p>(2) The progressive coarsening of the Carboniferous deposits westward -and their land derivation, together with the great thickness of the -series, point to an elevated land mass in process of<a name="page_249" id="page_249"></a> erosion west of -the series as a whole, that is west of the present coast.</p> - -<p>(3) The restricted development of the Cretaceous seas upon the western -border of the Carboniferous, and the still more restricted development -of the Tertiary deposits between the mountains and the present coast, -point to increasing definition of the submarine scarp through the -Mesozoic and the Tertiary.</p> - -<p>(4) The Tertiary deposits are all clearly derived from the present -mountains and have been washed seaward down slopes with geographic -relations approximately like those of the present.</p> - -<p>(5) From the great width, deep dissection, and subsequent burial of the -Tertiary terraces of the coast, it is clear that the greater part of the -adjustment of the crust to which the bordering ocean basin is due was -accomplished at least by mid-Tertiary time.</p> - -<p><a name="fig_168" id="fig_168"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_249_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_249_sml.jpg" width="280" height="185" alt="Fig. 168—Composite structure section representing the -succession of rocks in the Urubamba Valley from Urubamba to Torontoy." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 168—Composite structure section representing the -succession of rocks in the Urubamba Valley from Urubamba to Torontoy.</p> -</div> - -<p>Aside from the fossiliferous limestones of known Cretaceous age there -have been referred to the Cretaceous certain red sandstones and shales -marked, especially in the central portions of the Cordillera, by the -presence of large amounts of salt and gypsum. These beds were at first -considered Permian, but Steinmann has since found at Potosà related and -similar formations with Cretaceous fossils. In this connection it is -also necessary to add that the great red sandstone series forming the -eastern border of the Andes in Bolivia is of uncertain age and has -likewise been referred<a name="page_250" id="page_250"></a> to the Cretaceous, though the matter of its age -has not yet been definitely determined. In 1913 I found it appearing in -northwestern Argentina in the Calchaquà Valley in a relation to the main -Andean mass, similar to that displayed farther north. It contains -fossils and its age was, therefore, readily determinable there.<a name="FNanchor_53_53" id="FNanchor_53_53"></a><a href="#Footnote_53_53" class="fnanchor">[53]</a></p> - -<p>In the Peruvian field the red beds of questionable age were not examined -in sufficient detail to make possible a definite age determination. They -occur in a great and only moderately disturbed series in the Anta basin -north of Cuzco, but are there not fossiliferous. The northeastern side -of the hill back of Puqura (of the Anta basin: to be distinguished from -Puquiura in the Vilcabamba Valley) is composed largely of rocks of this -class. In a few places their calcareous members have been weathered out -in such a manner as to show karst topography. Where they occur on the -well-drained brow of a bluff the caves are used in place of houses by -Indian farmers. The large and strikingly beautiful Lake Huaipo, ten -miles north of Anta, and several smaller, neighboring lakes, appear to -have originated in solution depressions formed in these beds.</p> - -<p><a name="fig_169" id="fig_169"></a></p> -<p><a name="fig_170" id="fig_170"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_250a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_250a_sml.jpg" width="222" height="339" alt="Fig. 169—The line of unconformity between the igneous -basement rocks (agglomerates at this point) and the quartzites and -sandstones of the Urubamba Valley, between the town of Urubamba and -Ollantaytambo." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 169—The line of unconformity between the igneous -basement rocks (agglomerates at this point) and the quartzites and -sandstones of the Urubamba Valley, between the town of Urubamba and -Ollantaytambo.</p> - -<p class="caption"><span class="smcap">Fig. 170</span>—The inclined lower and horizontal upper -sandstone on the southeastern wall of the Majes Valley at Hacienda -Cantas. The section is a half-mile high.</p> -</div> - -<p>The structural relation of the red sandstone series to the older rocks -is well displayed about half-way between Urubamba and Ollantaytambo in -the deep Urubamba Valley. The basal rocks are slaty schist and granite -succeeded by agglomerates and basalt porphyries upon whose eroded -surfaces (<a href="#fig_169">Fig. 169</a>) are gray to yellow cross-bedded sandstones. Within a -few hundred feet of the unconformity gypsum deposits begin to appear and -increase in number to such an extent that the resulting soil is in -places rendered worthless. Copper-stained bands are also common near the -bottom of the series, but these are confined to the lower beds. Higher -up in the section, for example, just above the gorge between Urubamba -and Ollantaytambo, even-bedded sandstones occur whose most prominent -characteristic is the regular succession of<a name="page_251" id="page_251"></a> coarse and fine sandstone -beds. Such alternations of character in sedimentary rocks are commonly -marked by alternating shales and sandstones, but in this locality shales -are practically absent. Toward the top of the section gypsum deposits -again appear first as beds and later, as in the case of the hill-slope -on the southern shore of Lake Huaipo, as veins and irregular masses of -gypsum. The top of the deformed Cretaceous (?) is eroded and again -covered unconformably by practically flat-lying Tertiary deposits.</p> - -<h4>TERTIARY</h4> - -<p>The Tertiary deposits of the region under discussion are limited to -three regions: (1) the extreme eastern border of the main Cordillera, -(2) intermontane basins, the largest and most important of which are (a) -the Cuzco basin and (b) the Titicaca-Poopó basin on the -Peruvian-Bolivian frontier, and (3) in the west-coast desert and in -places upon the huge terraces that form a striking feature of the -topography of the coast of Peru.</p> - -<p>It has already been pointed out that the eastern border of the -Cordillera is marked by a fault of great but undetermined throw, whose -topographic importance may be estimated from the fact that even after -prolonged erosion it stands nearly four thousand feet high. Cross-bedded -and ripple-marked features and small lenses of conglomerate are common. -The beds now dip at an angle approximately 20° to 50° northward at the -base of the scarp, but have decreasing dip as they extend farther north -and east. It is noteworthy that the deposits become distinctly -conglomeratic as flatter dips are attained, and that there seems to have -been a steady accumulation of detrital material from the mountains for a -long period, since the deposits pass in unbroken succession from the -highly indurated and massive beds of the mountain base to loose -conglomerates that now weather down much like an ordinary gravel bank. -In a few places just below the mouth of the Ticumpinea, logs about six -inches in diameter were observed embeded in the deposits, but these -belong distinctly to the upper horizons.</p> - -<p>The border deposits, though they vary in dip from nearly flat<a name="page_252" id="page_252"></a> to 50°, -are everywhere somewhat inclined and now lie up to several hundred feet -above the level of the Urubamba River. Their upper surface is moderately -dissected, the degree of dissection being most pronounced where the dips -are steepest and the height greatest. In fact, the attitude of the -deposits and their progressive change in character point toward, if they -do not actually prove, the steady and progressive character of the beds -first deposited and their erosion and redeposition in beds now higher in -the series.</p> - -<p>Upon the eroded upper surfaces of the inclined border deposits, gravel -beds have been laid which, from evidence discussed in a later paragraph, -are without doubt referable to the Pleistocene. These in turn are now -dissected. They do not extend to the highest summits of the deformed -beds but are confined, so far as observations have gone, to elevations -about one hundred feet above the river. From the evidence that the -overlying horizontal beds are Pleistocene, the thick, inclined beds are -referred to Tertiary age, though they are nowhere fossiliferous.</p> - -<p>Observations along the Urubamba River were extended as far northward as -the mouth of the Timpia, one of the larger tributaries. Upon returning -from this point by land a wide view of the country was gained from the -four-thousand-foot ridge of vertical Carboniferous limestone, in which -it appeared that low and irregular strike ridges continue the features -of the Tertiary displayed along the mountain front far northward as well -as eastward, to a point where the higher ridges and low mountains of -older rock again appear—the last outliers of the Andean system in Peru. -Unfortunately time enough was not available for an extension of the trip -to these localities whose geologic characters still remain entirely -unknown. From the topographic aspects of the country, it is, however, -reasonably certain that the whole intervening depression between these -outlying ranges and the border of the main Cordillera, is filled with -inclined and now dissected and partly covered Tertiary strata. The -elevation of the upper surface does not, however, remain the same; it -appears to decrease steadily and the youngest Tertiary strata disappear<a name="page_253" id="page_253"></a> -from view below the sediments of either the Pleistocene or the present -river gravels. In the more central parts of the depression occupied by -the Urubamba Valley, only knobs or ridges project here and there above -the general level.</p> - -<h4><i>The Coastal Tertiary</i></h4> - -<p>The Tertiary deposits of the Peruvian desert region southwest of the -Andes have many special features related to coastal deformation, changes -of climate, and great Andean uplifts. They lie between the west coast of -Peru at Camaná and the high, lava-covered country that forms the western -border of the Andes and in places are over a mile thick. They are -non-fossiliferous, cross-bedded, ripple-marked, and have abundant lenses -of conglomerate of all sizes. The beds rest upon an irregular floor -developed upon a varied mass of rocks. In some places the basement -consists of old strata, strongly deformed and eroded. In other places it -consists of a granite allied in character and probably in origin with -the old granite-gneiss of the Coast Range toward the west. Elsewhere the -rock is lava, evidently the earliest in the great series of volcanic -flows that form this portion of the Andes.</p> - -<p>The deposits on the western border of the Andes are excellently exposed -in the Majes Valley, one of the most famous in Peru, though its fame -rests rather upon the excellence and abundance of its vineyards and -wines than its splendid geologic sections. Its head lies near the base -of the snow-capped peaks of Coropuna; its mouth is at Camaná on the -Pacific, a hundred miles north of Mollendo. It is both narrow and deep; -one may ride across its floor anywhere in a half hour. In places it is a -narrow canyon. Above Cantas it is sunk nearly a mile below the level of -the desert upland through which it flows. Along its borders are exposed -basal granites, old sedimentaries, and lavas; inter-bedded with it are -other lavas that lie near the base of the great volcanic series; through -it still project the old granites of the Coast Range; and upon it have -been accumulated additional volcanic rocks, wind-blown deposits, and, -finally, coarse wash formed during the glacial period. From both the -variety of the formations,<a name="page_254" id="page_254"></a> the small amount of marginal dissection, and -the excellent exposures made possible by the deep erosion and desert -climate, the Majes Valley is one of the most profitable places in Peru -for physiographic and geologic study.</p> - -<p><a name="fig_171" id="fig_171"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_254_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_254_sml.jpg" width="211" height="57" alt="Fig. 171—Generalized sketch section to show the -structural relations of the Maritime Cordillera, the desert pampas, and -the Coast Range." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 171—Generalized sketch section to show the -structural relations of the Maritime Cordillera, the desert pampas, and -the Coast Range.</p> -</div> - -<p>The most complete succession of strata (Tertiary) occurs just below -Cantas on the trail to Jaguey (<a href="#fig_171">Fig. 171</a>). Upon a floor of -granite-gneiss, and alternating beds of quartzite and shale belonging to -an older series, are deposited heavy beds of red sandstone with many -conglomerate lenses. The sandstone strata are measurably deformed and -their upper surfaces moderately dissected. Upon them have been deposited -unconformably a thicker series of deposits, conglomerates, sandstones, -and finer wind-blown material. The basal conglomerate is very -coarse—much like beach material in both structure and composition, and -similar to that along and south of the present coast at Camaná. Higher -in the section the material is prevailingly sandy and is deposited in -regular beds from a few inches to a few feet in thickness. Near the top -of the section are a few hundred feet of strata chiefly wind deposited. -Unconformably overlying the whole series and in sharp contrast to the -fine wind-blown stuff below it, is a third series of coarse deposits -about five hundred feet thick. The topmost material, that forming the -surface of the desert upland, consists of wind-blown sand now shifted by -the wind and gathered into sand dunes or irregular drifts, banks of -white earth, “tierra blanca,†and a pebble pavement a few inches thick.</p> - -<p>If the main facts of the above section are now summarized they will -facilitate an understanding of other sections about to be described, -inasmuch as the summary will in a measure anticipate<a name="page_255" id="page_255"></a> our conclusions -concerning the origin of the deposits and their subsequent history. The -sediments in the Majes Valley between Cantas and Jaguey consist of three -series separated by two unconformities. The lowermost series is evenly -bedded and rather uniform in composition and topographic expression, -standing forth in huge cliffs several hundred feet high on the eastern -side of the valley. This lower series is overlain by a second series, -which consists of coarse conglomerate grading into sand and ultimately -into very fine fluffy wind-deposited sands and silts. The lower series -is much more deformed than the upper, showing that the deforming -movements of later geologic times have been much less intense than the -earlier, as if there had been a fading out or weakening of the deforming -agents. Finally there is a third series several hundred feet thick which -forms the top of the section.</p> - -<p><a name="fig_172" id="fig_172"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_255a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_255a_sml.jpg" width="210" height="45" alt="Fig. 172—Geologic relations of Coast Range, desert -deposits, and Maritime Cordillera at Moquegua, Peru. After G. I. Adams; -Bol. de Minas del Perú, Vol. 2, No. 4, 1906, p. 20." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 172—Geologic relations of Coast Range, desert -deposits, and Maritime Cordillera at Moquegua, Peru. After G. I. Adams; -Bol. de Minas del Perú, Vol. 2, No. 4, 1906, p. 20.</p> -</div> - -<p><a name="fig_173" id="fig_173"></a></p> - -<div class="figright" style="width: 116px;"> -<a href="images/ill_page_255b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_255b_sml.jpg" width="116" height="28" alt="Fig. 173—Sketch section to show structural details on -the walls of the Majes Valley near Aplao, looking south." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 173—Sketch section to show structural details on -the walls of the Majes Valley near Aplao, looking south.</p> -</div> - -<p>Three other sections may now be examined, one immediately below Cantas, -one just above, and one opposite Aplao. The section below Cantas is -shown in <a href="#fig_173">173</a> , and indicates a lower series of red sandstones -crossed by vertical faults and unconformably overlain by nearly -horizontal conglomerates, sandstones, etc., and the whole faulted again -with an inclined fault having a throw of nearly 25°. A white to gray -sandstone unconformably overlying the red sandstone is shown -interpolated between the lowermost and uppermost series, the only -example of its kind, however. No important differences<a name="page_256" id="page_256"></a> in -lithographical character may be noted between these and the beds of the -preceding section.</p> - -<p>Again just above Cantas on the east side of the valley is a clean -section exposing about two thousand feet of strata in a half mile of -distance. The foundation rocks are old quartzites and shales in -regularly alternating beds. Upon their uneven upper surfaces are several -thousand feet of red sandstones and conglomerates, which are both folded -and faulted with the underlying quartzites. Above the red sandstones is -a thick series of gray sandstones and silts which makes the top of the -section and unconformably overlies the earlier series.</p> - -<p>A similar succession of strata was observed at Aplao, still farther up -the Majes Valley, <a href="#fig_174">174</a> . A greatly deformed and metamorphosed older -series is unconformably overlaid by a great thickness of younger strata. -The younger strata may be again divided into two series, a lower series -consisting chiefly of red sandstones and an upper consisting of gray to -yellow, and only locally red sands of finer texture and more uniform -composition. The two are separated by an erosion surface and only the -upper series is tilted regionally seaward with faint local deformation; -the lower series is both folded and faulted with overthrusts aggregating -several thousand feet of vertical and a half mile of horizontal -displacement.</p> - -<p><a name="fig_174" id="fig_174"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_256_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_256_sml.jpg" width="209" height="28" alt="Fig. 174—The structural relations of the strata on the -border of the Majes Valley at Aplao, looking west. Field sketch from -opposite side of valley. Height of section about 3,000 feet; length -about ten miles." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 174—The structural relations of the strata on the -border of the Majes Valley at Aplao, looking west. Field sketch from -opposite side of valley. Height of section about 3,000 feet; length -about ten miles.</p> -</div> - -<p>The above sections all lie on the eastern side of the Majes Valley. From -the upper edge of the valley extensive views were gained of the strata -on the opposite side, and two sections, though they were not examined at -close range, are at least worth comparing with those already given. From -the narrows below Cantas the structure appears as in Figs. 175-176, and -shows a deforming movement succeeded by erosion in a lower series. The -upper<a name="page_257" id="page_257"></a> series of sedimentary rock has suffered but slight deformation. A -still more highly deformed basal series occurs on the right of the -section, presumably the older quartzites. At Huancarqui, opposite Aplao, -an extensive view was gained of the western side of the valley, but the -lower Tertiary seems not to be represented here, as the upper undeformed -series rests unconformably upon a tilted series of quartzites and -slates. Farther up the Cantas valley (an hour’s ride above Aplao) the -Tertiary rests upon volcanic flows or older quartzites or the -granite-gneiss exposed here and there along the valley floor.</p> - -<p><a name="fig_175" id="fig_175"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_257a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_257a_sml.jpg" width="210" height="31" alt="Fig. 175—Sketch section to show the structural details -of the strata on the south wall of the Majes Valley near Cantas. The -section is two miles long." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 175—Sketch section to show the structural details -of the strata on the south wall of the Majes Valley near Cantas. The -section is two miles long.</p> -</div> - -<p><a name="fig_176" id="fig_176"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_257b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_257b_sml.jpg" width="211" height="31" alt="Fig. 176—Composite geologic section to show the -structural relations of the rocks on the western border of the Maritime -Cordillera. The inclined strata at the right bottom represent older -rocks; in places igneous, in other places sedimentary." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 176—Composite geologic section to show the -structural relations of the rocks on the western border of the Maritime -Cordillera. The inclined strata at the right bottom represent older -rocks; in places igneous, in other places sedimentary.</p> -</div> - -<p>In no part of the sedimentaries in the Majes Valley were fossils found, -save in the now uplifted and dissected sands that overlie the upraised -terraces along the coast immediately south of Camaná and also back of -Mollendo. Like similar coastal deposits elsewhere along the Peruvian -littoral, the terrace sands are of Pliocene or early Pleistocene age. -The age of the deposits back of the Coast Range is clearly greater than -that of the coastal deposits, (1) since they involve two unconformities, -a mile or more of sediments, and now stand at least a thousand feet -above the highest Pliocene (or Pleistocene) in the Camaná Valley, and -(2) because the erosion history of the interior sediments may be -correlated with the physiographic history of the coastal terraces and -the correlation shows that uplift and dissection of the terraces and of -the interior deposits went hand in hand, and that the deposits<a name="page_258" id="page_258"></a> on the -terraces may similarly be correlated with alluvial deposits in the -valley.</p> - -<p>We shall now see what further ground there is for the determination of -the age of these sediments. Just below Chuquibamba, where they first -appear, the sediments rest upon a floor of volcanic and older rock -belonging to the great field now known from evidence in many localities -to have been formed in the early Tertiary, and here known to be -post-Cretaceous from the relations between Cretaceous limestones and -volcanics in the Cotahuasi Valley (see p. <a href="#page_247">247</a>). Although volcanic flows -were noted interbedded with the desert deposits, these are few in -number, insignificant in volume, and belong to the top of the volcanic -series. The same may be said of the volcanic flows that locally overlie -the desert deposits. We have then definite proof that the sandstones, -conglomerates, and related formations of the Majes Valley and bordering -uplands are older than the Pliocene or early Pleistocene and younger -than the Cretaceous and the older Tertiary lavas. Hence it can scarcely -be doubted that they represent a considerable part of the Tertiary -period, especially in view of the long periods of accumulation which the -thick sediments represent, and the additional long periods represented -by the two well-marked unconformities between the three principal groups -of strata.</p> - -<p>If we now trace the physical history of the region we have first of all -a deep depression between the granite range along the coast and the -western flank of the Andes. Here and there, as in the Vitor, the Majes, -and other valleys, there were gaps through the Coast Range. Nowhere did -the relief of the coastal chain exceed 5,000 feet. The depression had -been partly filled in early geologic (probably early Paleozoic) time by -sediments later deformed and metamorphosed so that they are now -quartzites and shales. The greater resistance of the granite of the -Coast Range resulted in superior relief, while the older deformed -sedimentaries were deeply eroded, with the result that by the beginning -of the Tertiary the basin quality of the depression was again -emphasized. All these facts are expressed graphically in <a href="#fig_171">171</a> . On<a name="page_259" id="page_259"></a> -the western flanks of the granite range no corresponding sedimentary -deposits are found in this latitude. The sea thus appears to have stood -farther west of the Coast Range in Paleozoic times than at present.</p> - -<p><a name="fig_177" id="fig_177"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_259_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_259_sml.jpg" width="356" height="195" alt="Fig. 177—Composite structure section at Aplao." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 177—Composite structure section at Aplao.</p> -</div> - -<p>For the later history it is necessary to assemble the various Tertiary -sections described on the preceding pages. First of all we recognize -three quite distinct types of accumulations, for which we shall have to -postulate three sets of conditions and possibly three separate agents. -The first or lowermost consists of even-bedded deposits of red and gray -sandstones, the former color predominating. The material is in general -well-sorted save locally, where lenses and even thin beds of -conglomerate have been developed. There is, however, about the whole -series a uniformity and an orderliness in striking contrast to the -coarse, cross-bedded, and irregular material above the unconformity. On -their northeastern or inner margin the sandstones are notably coarser -and thicker, a natural result of proximity to the mountains, the source -of the material. The general absence of wind-blown deposits is marked; -these occur entirely along the eastern and northern portions of the -deposits and are recognized (1) by their peculiar cross-bedding, and (2) -by the fact that the cross-bedding is directed northeastward in a -direction contrary to the regional dip of the series, a condition -attributable to the strong sea breezes that prevail every afternoon in -this latitude.</p> - -<p>The main body of the material is such as might be deposited on the wide -flood plains of piedmont streams during a period of<a name="page_260" id="page_260"></a> prolonged erosion -on surrounding highlands that served as the feeding grounds of the -streams. The alternations in the character of the deposits, alternations -which, in a general view, give a banded appearance to the rock, are -produced by successions of beds of fine and coarse material, though all -of it is sandstone. Such successions are probably to be correlated with -seasonal changes in the volume and load of the depositing streams.</p> - -<p>To gain an idea of the conditions of deposition we may take the -character of the sediments as described above, and from them draw -deductions as to the agents concerned and the manner of their action.</p> - -<p>We may also apply to the area the conclusions drawn from the study of -similar deposits now in process of formation. We have between the coast -ranges of northern Chile and the western flanks of the Cordillera -Sillilica, probably the best example of piedmont accumulation in a dry -climate that the west coast of South America affords.</p> - -<p>Along the inner edge of the Desert of Tarapacá, roughly between the -towns of Tarapacá and Quillagua, Chile, the piedmont gravels, sands, -silts, and muds extend for over a hundred miles, flanking the western -Andes and forming a transition belt between these mountains and the -interior basins of the coast desert. The silts and muds constitute the -outer fringe of the piedmont and are interrupted here and there where -sands are blown upon them from the higher portions of the piedmont, or -from the desert mountains and plains on the seaward side. Practically no -rain falls upon the greater part of the desert and the only water it -receives is that borne to it by the piedmont streams in the early -summer, from the rains and melted snows of the high plateau and -mountains to the eastward. These temporary streams spread upon the outer -edge of the piedmont a wide sheet of mud and silt which then dries and -becomes cracked, the curled and warped plates retaining their character -until the next wet season or until covered with wind-blown sand. The -wind-driven sand fills the cracks in the muds and is even drifted under -the edges of the upcurled plates, filling the spaces completely. Over -this combined<a name="page_261" id="page_261"></a> fluvial and æolian deposit is spread the next layer of -mud, which frequently is less extensive than the earlier deposits, thus -giving abundant opportunity for the observation of the exact manner of -burial of the older sand-covered stratum.</p> - -<p>Now while the alternations are as marked in Peru as in Chile, it is -noteworthy that the Tertiary material in Peru is not only coarse -throughout, even to the farthest limits of the piedmont, but also that -the alternating beds are thick. Moreover, there are only the most feeble -evidences of wind action in the lowermost Tertiary series. I was -prepared to find curled plates, wind-blown sands, and muds and silts, -but they are almost wholly absent. It is, therefore, concluded that the -dryness was far less extreme than it is today and that full streams of -great competency flowed vigorously down from the mountains and carried -their loads to the inner border of the Coast Range and in places to the -sea.</p> - -<p>The fact that the finer material is <i>sandy</i>, not clayey or silty, that -it almost equals in thickness the coarser layers, and that its -distribution appears to be co-extensive with the coarser, warrants the -conclusion that it too was deposited by competent streams of a type far -different from the withering streams associated with piedmont deposits -in a thoroughly arid climate like that of today. Both in the second -Tertiary series and on the present surface are such clear examples of -deposits made in a drier climate as to leave little doubt that the -earliest of the Tertiary strata of the Majes Valley were deposited in a -time of far greater rainfall than the present. It is further concluded -that there was increasing dryness, as shown by hundreds of feet of -wind-blown sand near the top of the section. But the growing dryness was -interrupted by at least one period of greater precipitation. Since that -time there has been a return to the dry climate of a former epoch.</p> - -<p>Uplift and erosion of the earliest of the Tertiary deposits of the Majes -Valley is indicated in two ways: (1) by the deformed character of the -beds, and (2) by the ensuing coarse deposits which were derived from the -invigorated streams. Without strong deformations it would not be -possible to assign the increased erosion so confidently to uplift; with -the coarse deposits<a name="page_262" id="page_262"></a> that succeed the unconformity we have evidence of -accumulation under conditions of renewed uplift in the mountains and of -full streams competent to remove the increasing load.</p> - -<p>It is in the character of the sediments toward the top of the Tertiary -that we have the clearest evidence of progressive desiccation of the -climate of the region. The amount of wind-blown material steadily -increases and the uppermost five hundred feet is composed predominantly, -and in places exclusively, of this material. The evidences of wind -action lie chiefly in the fine (in places fluffy) nature of the -deposits, their uniform character, and in the tangency of the layers -with respect to the surface on which they were deposited. There are -three diagnostic structural features of great importance: the very steep -dip of the fine laminae; the peculiar and harmonious blending of their -contacts; the manner in which the highly inclined laminae cut off and -succeed each other, whereby quite bewildering changes in the direction -of dip of the inclined beds are brought about on any exposed plane. Some -of these features require further discussion.</p> - -<p>It is well known that the front of a sand dune generally consists of -sand deposited on a slope inclined at the angle of repose, say between -30° and 35°, and rolled into place up the long back slope of the dune by -the wind. It has not, however, been generally recognized that the angle -of repose may be exceeded (a) when there exists a strong back eddy or -(b) when the wind blows violently and for a short time in the opposite -direction. In either case sand is carried up the short steep slope of -the dune front and accumulated at an angle not infrequently running up -to 43° and 48° and locally, and under the most favorable circumstances, -in excess of 50°. The conditions under which these steep angles are -attained are undoubtedly not universal, but they can be found in some -parts of almost any desert in the world. They appear not to be present -where the sand grains are of uniform size throughout, since that leads -to rolling. They are found rather where there is a certain limited -variation in size that promotes packing. Packing and the development of -steep slopes are also facilitated in parts of the coastal desert of Peru -by a cloud canopy that hangs<a name="page_263" id="page_263"></a> over the desert in the early morning, that -in the most favorable places moistens even the dune surfaces and that -has least penetration on the steep semi-protected dune fronts. Sand -later blown up the dune front or rolled down from the dune crest is -encouraged to remain near the cornice on an abnormally steep slope by -the attraction which the slightly moister sand has for the dry grains -blown against it. Since dunes travel and since their front layers, -formed on steep slopes, are cut off to the level of the surface in the -rear of the dune, it follows that the steepest dips in exposed sections -are almost always less than those in existing dunes. Exceptions to the -rule will be noted in filled hollows not re-excavated until deeply -covered by wind-blown material. These, re-exposed at the end of a long -period of wind accumulation, may exhibit even the maximum dips of the -dune cornices. Such will be conspicuously the case in sections in -aggraded desert deposits. On the border of the Majes Valley, from 400 to -500 feet of wind-accumulated deposits may be observed, representing a -long period of successive dune burials.</p> - -<p>The peculiar blending of the contact lines of dune laminae, related to -the tangency commonly noted in dune accumulations, is apparently due to -the fact that the wind does not require a graded surface to work on, but -blows uphill as well as down. It is present on both the back-slope and -the front-slope deposits. Its finest expression appears to be in -districts where the dune material was accumulated by a violent wind -whose effects the less powerful winds could not destroy.</p> - -<p>It is to the ability of the wind to transport material against, as well -as with, gravity, that we owe the third distinct quality of dune -material, the succession of flowing lines, in contrast to the succession -of now flat-lying now steeply inclined beds characteristic of -cross-bedded material deposited by water. One dune travels across the -face of the country only to be succeeded by another.<a name="FNanchor_54_54" id="FNanchor_54_54"></a><a href="#Footnote_54_54" class="fnanchor">[54]</a> Even if wind -aggradation is in progress, the plain-like surface in the rear of a dune -may be excavated to the level of steeply inclined<a name="page_264" id="page_264"></a> beds upon whose -truncated outcrop other inclined beds are laid, <a href="#fig_178">178</a> . The contrast -to these conditions in the case of aggradation by water is so clearly -and easily inferred that space will not be taken to point them out. It -is also true as a corollary to the above that the greater part of a body -of wind-drifted material will consist of cross-bedded layers, and not a -series of evenly divided and alternating flat-lying and cross-bedded -layers which result from deposition in active and variable currents of -water.</p> - -<p>The caution must of course be observed that wind action and water action -may alternate in a desert region, as already described in Tarapacá in -northern Chile, so that the whole of a deposit may exhibit an -alternation of cross-bedded and flat-lying layers; but the former only -are due to wind action, the latter to water action.</p> - -<p>Finally it may be noted that the sudden, frequent, and diversified dips -in the cross-bedding are peculiarly characteristic of wind action. -Although one sees in a given cross-section dips apparently directed only -toward the left or the right, excavation will supply a third dimension -from which the true dips may be either observed or calculated. These -show an almost infinite variety of directions of dip, even in restricted -areas, a condition due to the following causes:</p> - -<p>(1) the curved fronts of sand dunes, which produce dips concentric with -respect to a point and ranging through 180° of arc; (2) the irregular -character of sand dunes in many places, a condition due in turn to (a) -the changeful character of the strong wind (often not the prevailing -wind) to which the formation of the dunes is due, and (b) the influence -of the local topography upon wind directions within short distances or -upon winds of different directions in which a slight change in wind -direction is followed by a large change in the local currents; (3) the -fact that all combinations are possible between the erosion levels of -the wind in successive generations of dunes blown across a given area, -hence <i>any</i> condition at a given level in a dune may be combined with -<i>any other</i> condition of a succeeding dune; (4) variations in the sizes -of successive dunes will lead to further contrasts<a name="page_265" id="page_265"></a><a name="page_266" id="page_266"></a> not only in the -scale of the features but also in the direction and amount of the dips.</p> - -<p><a name="fig_178" id="fig_178"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_265_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_265_sml.jpg" width="216" height="257" alt="Fig. 178—Plan and cross-sections of superimposed sand -dunes of conventional outline. In the sections, dune A is supposed to -have left only a small basal portion to be covered by dune B. In the -same way dune C has advanced to cover both A and B. The basal -portions that have remained are exaggerated vertically in order to -display the stratification. It is obviously not necessary that the dunes -should all be of the same size and shape and advancing in the same -direction in order to have the tangential relations here displayed. Nor -need the aggrading material be derived from true dunes. The results -would be the same in the case of sand drifts with their associated -wind eddies. All bedded wind-blown deposits would have the same general -relations. No two successive deposits, no matter from what direction the -successive drifts or dunes travel, would exactly correspond in direction -and amount of dip." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 178—Plan and cross-sections of superimposed sand -dunes of conventional outline. In the sections, dune A is supposed to -have left only a small basal portion to be covered by dune B. In the -same way dune C has advanced to cover both A and B. The basal -portions that have remained are exaggerated vertically in order to -display the stratification. It is obviously not necessary that the dunes -should all be of the same size and shape and advancing in the same -direction in order to have the tangential relations here displayed. Nor -need the aggrading material be derived from true dunes. The results -would be the same in the case of sand drifts with their associated -wind eddies. All bedded wind-blown deposits would have the same general -relations. No two successive deposits, no matter from what direction the -successive drifts or dunes travel, would exactly correspond in direction -and amount of dip.</p> -</div> - -<p>Finally, we may note that a section of dune deposits has a distinctive -feature not exhibited by water deposits. If the foreset beds of a -cross-bedded water deposit be exposed in a plane parallel to the strike -of the beds, the beds will appear to be horizontal. They could not then -be distinguished from the truly horizontal beds above and below them. -But the conditions of wind deposition we have just noted, and chiefly -the facts expressed by <a href="#fig_178">178</a> , make it impossible to select a position -in which both tangency and irregular dips are not well developed in a -wind deposit. I believe that we have in the foregoing facts and -inferences a means for the definite separation of these two classes of -deposits. Difficulties will arise only when there is a quick succession -of wind and water action in time, or where the wind produces powerful -and persistent effects without the actual formation of dunes.</p> - -<p>The latest known deposits in the coastal region are found surmounting -the terrace tops along the coast between Camaná and Quilca, where they -form deposits several hundred feet thick in places. The age of these -deposits is determined by fossil evidence, and is of extraordinary -interest in the determination of the age of the great terraces upon -which they lie. They consist of alternating beds of coarse and fine -material, the coarser increasing in thickness and frequency toward the -bottom of the section. It is also near the bottom of the section that -fossils are now found; the higher members are locally saline and -throughout there is a marked inclination of the beds toward the present -shore. The deposits appear not to have been derived from the underlying -granite-gneiss. They are distributed most abundantly near the mouths of -the larger streams, as near the Vitor at Quilca, and the Majes at -Camaná. Elsewhere the terrace summit is swept clean of waste, except -where local clay deposits lie in the ravines, as back of Mollendo and -where “tierras blancas†have been accumulated by the wind.</p> - -<p>These coastal deposits were laid down upon a dissected terrace<a name="page_267" id="page_267"></a> up to -five miles in width. The degree of dissection is variable, and depends -upon the relation of the through-flowing streams to the Coast Range. The -Vitor and the Majes have cut down through the Coast Range, and locally -removed the terrace; smaller streams rising on the flanks of the Coast -Range either die out near the foot of the range or cross it in deep and -narrow valleys. The present drainage on the seaward slopes of the Coast -Range is entirely ineffective in reaching the sea, as was seen in 1911, -the wettest season known on the coast in years and one of the wettest -probably ever observed on this coast by man.</p> - -<p>In consequence of their deposition on a terrace that ranges in elevation -from zero to 1,500 feet above sea level, the deposits of the coast are -very irregularly disposed. But in consequence of their great bulk they -have a rather smooth upper surface, gradation having been carried to the -point where the irregularities of the dissected terrace were smoothed -out. Their general uniformity is broken where streams cross them, or -where streams crossed them during the wetter Pleistocene. Their -elevation, several hundred feet above sea level, is responsible for the -deep dissection of their coastal margin, where great cliffs have been -cut.</p> - -<h4>PLEISTOCENE</h4> - -<p>The broad regional uplift of the Peruvian Andes in late Tertiary and in -Pleistocene times carried their summits above the level of perpetual -snow. It is still an open question whether or not uplift was -sufficiently great in the early Pleistocene to be influenced by the -first glaciations of that period. As yet, there are evidences of only -two glacial invasions, and both are considered late events on account of -the freshness of their deposits and the related topographic forms. The -coarse deposits—nearly 500 feet thick—that form the top of the desert -section described above clearly indicate a wetter climate than prevailed -during the deposition of the several hundred feet of wind-blown deposits -beneath them. But if our interpretation be correct these deposits are of -late Tertiary age, and their character and position are taken to -indicate climatic changes in the Tertiary. They may<a name="page_268" id="page_268"></a> have been the mild -precursors of the greater climatic changes of glacial times. Certain it -is that they are quite unlike the mass of the Tertiary deposits. On the -other hand they are separated from the deposits of known glacial age by -a time interval of great length—an epoch in which was cut a benched -canyon nearly a mile deep and three miles wide. They must, therefore, -have been formed when the Andes were thousands of feet lower and unable -to nourish glaciers. It was only after the succeeding uplifts had raised -the mountain crests well above the frost line that the records of -oscillating climates were left in erratic deposits, troughed valleys, -cliffed cirques and pinnacled divides.</p> - -<p>The glacial forms are chiefly at the top of the country; the glacial -deposits are chiefly in the deep valleys that were carved before the -colder climate set in. The rock waste ground up by the ice was only a -small part of that delivered to the streams in glacial times. Everywhere -the wetter climate resulted in the partial stripping of the residual -soil gathered upon the smooth mature slopes formed during the long -Tertiary cycle of erosion. This moving sheet of waste as well as the -rock fragments carried away from the glacier ends were strewn along the -valley floors, forming a deep alluvial fill. Thereby the canyon floors -were rendered habitable.</p> - -<p>In the chapters on human geography we have already called attention to -the importance of the U-shaped valleys carved by the glaciers. Their -floors are broad and relatively smooth. Their walls restrain the live -stock. They are sheltered though lofty. But all the human benefits -conferred by ice action are insignificant beside those due to the -general shedding of waste from the cold upper surfaces to the warm -levels of the valley floors. The alluvium-filled valleys are the seats -of dense populations. In the lowest of them tropical and sub-tropical -products are raised, like sugar-cane and cotton, in a soil that once lay -on the smooth upper slopes of mountain spurs or that was ground fine on -the bed of an Alpine glacier.</p> - -<p><a name="fig_179" id="fig_179"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_268a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_268a_sml.jpg" width="217" height="340" alt="Fig. 179—Snow fields on the summit of the Cordillera -Vilcapampa near Ollantaytambo. A huge glacier once lay in the steep -canyon in the background and descended to the notched terminal moraine -at the canyon mouth. In places the glacier was over a thousand feet -thick. From the terminal moraine an enormous alluvial fan extends -forward to the camera and to the opposite wall of the Urubamba Valley. -It is confluent with other fans of the same origin. See Fig. 180. In the -foreground are flowers, shrubs, and cacti. A few miles below Urubamba at -11,500 feet." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 179—Snow fields on the summit of the Cordillera -Vilcapampa near Ollantaytambo. A huge glacier once lay in the steep -canyon in the background and descended to the notched terminal moraine -at the canyon mouth. In places the glacier was over a thousand feet -thick. From the terminal moraine an enormous alluvial fan extends -forward to the camera and to the opposite wall of the Urubamba Valley. -It is confluent with other fans of the same origin. See <a href="#fig_180">Fig. 180</a>. In the -foreground are flowers, shrubs, and cacti. A few miles below Urubamba at -11,500 feet.</p> -</div> - -<p><a name="fig_180" id="fig_180"></a></p> -<p><a name="fig_181" id="fig_181"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_268b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_268b_sml.jpg" width="217" height="339" alt="Fig. 180—Urubamba Valley between Ollantaytambo and -Torontoy, showing (1) more moderate upper slopes and steeper lower -slopes of the two-cycle mountain spurs; (2) the extensive alluvial -deposits of the valley, consisting chiefly of confluent alluvial fans -heading in the glaciated mountains on the left. See Fig. 179." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 180—Urubamba Valley between Ollantaytambo and -Torontoy, showing (1) more moderate upper slopes and steeper lower -slopes of the two-cycle mountain spurs; (2) the extensive alluvial -deposits of the valley, consisting chiefly of confluent alluvial fans -heading in the glaciated mountains on the left. See <a href="#fig_179">Fig. 179</a>.</p> - -<p class="caption"><span class="smcap">Fig. 181</span>—Glacial features of the Central Ranges (see -<a href="#fig_204">Fig. 204</a>). Huge lateral moraines built by ice streams tributary to the -main valley north of Chuquibambilla. That the tributaries persisted long -after the main valley became free of ice is shown by the descent of the -lateral moraines over the steep border of the main valley and down to -the floor of it.</p> -</div> - -<p>The Pleistocene deposits fall into three well-defined groups: (1) -glacial accumulations at the valley heads, (2) alluvial deposits<a name="page_269" id="page_269"></a> in -the valleys, and (3) lacustrine deposits formed on the floors of -temporary lakes in inclosed basins. Among these the most variable in -form and composition are the true glacier-laid deposits at the valley -heads. The most extensive are the fluvial deposits accumulated as valley -fill throughout the entire Andean realm. Though important enough in some -respects the lacustrine deposits are of small extent and of rather local -significance. Practically none of them fall within the field of the -present expedition; hence we shall describe only the first two classes.</p> - -<p>The most important glacial deposits were accumulated in the eastern part -of the Andes as a result of greater precipitation, a lower snowline, and -catchment basins of larger area. In the Cordillera Vilcapampa glaciers -once existed up to twelve and fifteen miles in length, and those several -miles long were numerous both here and throughout the higher portions of -the entire Cordillera, save in the belt of most intense volcanic action, -which coincides with the driest part of the Andes, where the glaciers -were either very short or wanting altogether.</p> - -<p>Since vigorous glacial action results in general in the cleaning out of -the valley heads, no deposits of consequence occur in these locations. -Down valley, however, glacial deposits occur in the form of terminal -moraines of recession and ground moraines. The general nature of these -deposits is now so well known that detailed description seems quite -unnecessary except in the case of unusual features.</p> - -<p>It is noteworthy that the moraines decrease in size up valley since each -valley had been largely cleaned out by ice action before the retreat of -the glacier began. Each lowermost terminal moraine is fronted by a great -mass of unsorted coarse bowldery material forming a fill in places -several hundred feet thick, as below Choquetira and in the Vilcapampa -Valley between Vilcabamba and Puquiura. This bowldery fill is quite -distinct from the long, gently inclined, and stratified valley train -below it, or the marked ridge-like moraine above it. It is in places a -good half mile in length. Its origin is believed to be due to an -overriding action beyond the last terminal moraine at a time when the -ice<a name="page_270" id="page_270"></a> was well charged with débris, an overriding not marked by morainal -accumulations, chiefly because the ice did not maintain an extreme -position for a long period.</p> - -<p>In the vicinity of the terminal moraines the alluvial valley fill is -often so coarse and so unorganized as to look like till in the cut banks -along the streams, though its alluvial origin is always shown by the -topographic form. This characteristic is of special geologic interest -since the form may be concealed through deposition or destroyed by -erosion, and no condition but the structure remain to indicate the -manner of origin of the deposit. In such an event it would not be -possible to distinguish between alluvium and till. The gravity of the -distinction appears when it is known that such apparently unsorted -alluvium may extend for several miles forward of a terminal moraine, in -the shape of a widespreading alluvial fan apparently formed under -conditions of extremely rapid aggradation. I suppose it would not be -doubted in general that a section of such stony, bowldery, unsorted -material two miles long would have other than a glacial origin, yet such -may be the case. Indeed, if, as in the Urubamba Valley, a future section -should run parallel to the valley across the heads of a great series of -fans of similar composition, topographic form, and origin, it would be -possible to see many miles of such material.</p> - -<p>The depth of the alluvial valley fill due to tributary fan accumulation -depends upon both the amount of the material and the form of the valley. -Below Urubamba in the Urubamba Valley a fine series is displayed, as -shown in <a href="#fig_180">180</a> . The fans head in valleys extending up to snow-covered -summits upon whose flanks living glaciers are at work today. Their heads -are now crowned by terminal moraines and both moraines and alluvial fans -are in process of dissection. The height and extent of the moraines and -the alluvial fans are in rough proportion and in turn reflect the -height, elevation, and extent of the valley heads which served as fields -of nourishment for the Pleistocene glaciers. Where the fans were -deposited in narrow valleys the effect was to increase the thickness of -the deposits at the expense of their area, to dam the drainage lines or -displace them, and to so load the streams that<a name="page_271" id="page_271"></a> they have not yet -cleared their beds after thousands of years of work under torrential -conditions.</p> - -<p>Below Urubamba the alluvial fans entering the main valley from the east -have pushed the river against its western valley wall, so that the river -flows on one side against rock and on the other against a hundred feet -of stratified material. In places, as at the head of the narrows on the -valley trail to Ollantaytambo, a flood plain has been formed in front of -the scarp cut into the alluvium, while the edge of the dissected -alluvial fans has been sculptured into erosion forms resembling -bad-lands topography. On the western side of the valley the alluvial -fans are very small, since they are due to purely local accumulations of -waste from the edge of the plateau. Glaciation has here displaced the -river. Its effects will long be felt in the disproportionate erosion of -the western wall of the valley.</p> - -<p>By far the most interesting of the deposits of glacial time are those -laid down on the valley floors in the form of an alluvial fill. Though -such deposits have greater thickness as a rule near the nourishing -moraines or bordering alluvial fans at the lower ends of the valleys, -they are everywhere important in amount, distinctive in topographic -form, and of amazingly wide extent. They reach far into and possibly -across the Amazon basin, they form a distinct though small piedmont -fringe along the eastern base of the Andes, and they are universal -throughout the Andean valleys. That a deposit of such volume—many times -greater than all the material accumulated in the form of high-level -alluvial fans or terminal moraines—should originate in a tropical land -in a region that suffered but limited Alpine glaciation vastly increases -its importance.</p> - -<p><a name="fig_182" id="fig_182"></a></p> - -<div class="figright" style="width: 156px;"> -<a href="images/ill_page_271_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_271_sml.jpg" width="116" height="45" alt="Fig. 182—Dissected alluvial fans on the border of the -Urubamba Valley near Hacienda Chinche. A Characteristic feature of the -valleys of the Peruvian Andes below the zone of glaciation but within -the limits of its aggraditional effects. Through alluviation the valleys -and basins of the Andean Cordillera, and vast areas of the great Amazon -plains east of it, felt the effects of the glacial conditions of a past -age." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 182—Dissected alluvial fans on the border of the -Urubamba Valley near Hacienda Chinche. A Characteristic feature of the -valleys of the Peruvian Andes below the zone of glaciation but within -the limits of its aggraditional effects. Through alluviation the valleys -and basins of the Andean Cordillera, and vast areas of the great Amazon -plains east of it, felt the effects of the glacial conditions of a past -age.</p> -</div> - -<p><a name="page_272" id="page_272"></a></p> - -<p>The fill is composed of both fine and coarse material laid down by water -in steep valley floors to a depth of many feet. It breaks the steep -slope of each valley, forming terraces with pronounced frontal scarps -facing the river. On the raw bluffs at the scarps made by the -encroaching stream good exposures are afforded. At Chinche in the -Urubamba Valley above Santa Ana, the material is both sand and clay with -an important amount of gravel laid down with steep valleyward -inclination and under torrential conditions; so that within a given bed -there may be an apparent absence of lamination. Almost identical -conditions are exhibited frequently along the railway to Cuzco in the -Vilcanota Valley. The material is mixed sand and gravel, here and there -running to a bowldery or stony mass where accessions have been received -from some source nearby. It is modified along its margin not only in -topographic form but also in composition by small tributary alluvial -fans, though these in general constitute but a small part of the total -mass. At Cotahuasi, <a href="#fig_29">29</a> , there is a remarkable fill at least four -hundred feet deep in many places where the river has exposed fine -sections. The depth of the fill is, however, not determined by the -height of the erosion bluffs cut into it, since the bed of the river is -made of the same material. The rock floor of the valley is probably at -least an additional hundred feet below the present level of the river.</p> - -<p><a name="fig_183" id="fig_183"></a></p> - -<div class="figleft" style="width: 156px;"> -<a href="images/ill_page_272_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_272_sml.jpg" width="116" height="49" alt="Fig. 183—Two-cycle slopes and alluvial fill between -Iluichihua and Chuquibambilla. The steep slopes on the inner valley -border are in many places vertical and rock cliffs are everywhere -abundant. Mature slopes have their greatest development here between -13,500 and 15,000 feet (4,110 to 4,570 m.). Steepest mature slopes run -from 15° to 21°. Least steep are the almost level spur summits. The -depths of the valley fill must be at least 300, and may possibly be 500 -feet. The break between valley fill and steep slopes is most pronounced -where the river runs along the valley wall or undercuts it; least -pronounced where alluvial fans spread out from the head of some ravine. -It is a bowldery, stony fill almost everywhere terraced and cultivated." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 183—Two-cycle slopes and alluvial fill between -Iluichihua and Chuquibambilla. The steep slopes on the inner valley -border are in many places vertical and rock cliffs are everywhere -abundant. Mature slopes have their greatest development here between -13,500 and 15,000 feet (4,110 to 4,570 m.). Steepest mature slopes run -from 15° to 21°. Least steep are the almost level spur summits. The -depths of the valley fill must be at least 300, and may possibly be 500 -feet. The break between valley fill and steep slopes is most pronounced -where the river runs along the valley wall or undercuts it; least -pronounced where alluvial fans spread out from the head of some ravine. -It is a bowldery, stony fill almost everywhere terraced and cultivated.</p> -</div> - -<p>Similar conditions are well displayed at Huadquiña, where a fine series -of terraces at the lower end of the Torontoy Canyon break the descent of -the environing slopes; also in the Urubamba<a name="page_273" id="page_273"></a> Valley below Rosalina, and -again at the edge of the mountains at the Pongo de Mainique. It is -exhibited most impressively in the Majes Valley, where the bordering -slopes appear to be buried knee-deep in waste, and where from any -reasonable downward extension of rock walls of the valley there would -appear to be at least a half mile of it. It is doubtful and indeed -improbable that the entire fill of the Majes Valley is glacial, for -during the Pliocene or early Pleistocene there was a submergence which -gave opportunity for the partial filling of the valley with non-glacial -alluvium, upon which the glacial deposits were laid as upon a flat and -extensive floor that gives an exaggerated impression of their depth. -However, the head of the Majes Valley contains at least six hundred feet -and probably as much as eight hundred feet of alluvium now in process of -dissection, whose coarse texture and position indicates an origin under -glacial conditions. The fact argues for the great thickness of the -alluvial material of the lower valley, even granting a floor of Pliocene -or early Pleistocene sediments. The best sections are to be found just -below Chuquibamba and again about halfway between that city and Aplao, -whereas the best display of the still even-floored parts of the valley -are between Aplao and Cantas, where the braided river still deposits -coarse gravels upon its wide flood plain.<a name="page_274" id="page_274"></a></p> - -<h3><a name="CHAPTER_XVI" id="CHAPTER_XVI"></a>CHAPTER XVI<br /><br /> -GLACIAL FEATURES</h3> - -<h4>THE SNOWLINE</h4> - -<p>South America is classical ground in the study of tropical snowlines. -The African mountains that reach above the snowline in the equatorial -belt—Ruwenzori, Kibo, and Kenia—have only been studied recently -because they are remote from the sea and surrounded by bamboo jungle and -heavy tropical forest. On the other hand, many of the tropical mountains -of South America lie so near the west coast as to be visible from it and -have been studied for over a hundred years. From the days of Humboldt -(1800) and Boussingault (1825) down to the present, observations in the -Andes have been made by an increasing number of scientific travelers. -The result is a large body of data upon which comparative studies may -now be profitably undertaken.</p> - -<p>Like scattered geographic observations of many other kinds, the earlier -studies on the snowline have increased in value with time, because the -snowline is a function of climatic elements that are subject to periodic -changes in intensity and cannot be understood by reference to a single -observation. Since the discovery of physical proofs of climatic changes -in short cycles, studies have been made to determine the direction and -rate of change of the snowline the world over, with some very striking -results.</p> - -<p>It has been found<a name="FNanchor_55_55" id="FNanchor_55_55"></a><a href="#Footnote_55_55" class="fnanchor">[55]</a> that the changes run in cycles of from thirty to -thirty-five years in length and that the northern and southern -hemispheres appear to be in opposite phase. For example, since 1885 the -snowline in the southern hemisphere has been decreasing in elevation in -nine out of twelve cases by the average amount of nine hundred feet. -With but a single exception,<a name="page_275" id="page_275"></a> the snowline in the northern hemisphere -has been rising since 1890 with an average increase of five hundred feet -in sixteen cases. To be sure, we must recognize that the observations -upon which these conclusions rest have unequal value, due both to -personal factors and to differences in instrumental methods, but that in -spite of these tendencies toward inequality they should agree in -establishing a general rise of the snowline in the northern hemisphere -and an opposite effect in the southern is of the highest significance.</p> - -<p>It must also be realized that snowline observations are altogether too -meager and scattered in view of the abundant opportunities for making -them, that they should be standardized, and that they must extend over a -much longer period before they attain their full value in problems in -climatic variations. Once the possible significance of snowline changes -is appreciated the number and accuracy of observations on the elevation -and local climatic relations of the snowline should rapidly increase.</p> - -<p>In 1907 I made a number of observations on the height of the snowline in -the Bolivian and Chilean Andes between latitudes 17° and 20° south, and -in 1911 extended the work northward into the Peruvian Andes along the -seventy-third meridian. It is proposed here to assemble these -observations and, upon comparison with published data, to make a few -interpretations.</p> - -<p>From Central Lagunas, Chile, I went northeastward via Pica and the -Huasco Basin to Llica, Bolivia, crossing the Sillilica Pass in May, -1907, at 15,750 feet (4,800 m.). Perpetual snow lay at an estimated -height of 2,000-2,500 feet above the pass or 18,000 feet (5,490 m.) -above the sea. Two weeks later the Huasco Basin, 14,050 feet (4,280 m.), -was covered a half-foot deep with snow and a continuous snow mantle -extended down to 13,000 feet. Light snows are reported from 12,000 feet, -but they remain a few hours only and are restricted to the height of -exceptionally severe winter seasons (June and early July). Three or four -distant snow-capped peaks were observed and estimates made of the -elevation of the snowline between the Cordillera Sillilica and Llica on -the eastern border of the Maritime Cordillera. All observations<a name="page_276" id="page_276"></a> agreed -in giving an elevation much in excess of 17,000 feet. In general the -values run from 18,000 to 19,000 feet (5,490 to 5,790 m.). Though the -bases of these figures are estimates, it should be noted that a large -part of the trail lies between 14,000 and 16,000 feet, passing mountains -snow-free at least 2,000 to 3,000 feet higher, and that for general -comparisons they have a distinct value.</p> - -<p>In the Eastern Cordillera of Bolivia, snow was observed on the summit of -the Tunari group of peaks northwest of Cochabamba. Steinmann, who -visited the region in 1904, but did not reach the summit of the Tunari -group of peaks, concludes that the limit of perpetual snow should be -placed above the highest point, 17,300 (5,270 m.); but in July and -August, 1907, I saw a rather extensive snow cover over at least the -upper 1,000 feet, and what appeared to be a very small glacier. Certain -it is that the Cochabamba Indians bring clear blue ice from the Tunari -to the principal hotels, just as ice is brought to Cliza from the peaks -above Arani. On these grounds I am inclined to place the snowline at -17,000 feet (5,180 m.) near the eastern border of the Eastern -Cordillera, latitude 17° S. At 13,000 feet, in July, 1907, snow occurred -in patches only on the pass called Abre de Malaga, northeast of Colomi, -13,000 feet, and fell thickly while we were descending the northern -slopes toward Corral, so that in the early morning it extended to the -cold timber line at 10,000 feet. In a few hours, however, it had -vanished from all but the higher and the shadier situations.</p> - -<p>In the Vilcanota knot above the divide between the Titicaca and -Vilcanota hydrographic systems, the elevation of the snowline was -16,300+ feet (4,970 m.) in September, 1907. On the Cordillera Real of -Bolivia it is 17,000 to 17,500 feet on the northeast, but falls to -16,000 feet on the southwest above La Paz. In the first week of July, -1911, snow fell on the streets of Cuzco (11,000 feet) and remained for -over an hour. The heights north of San Geronimo (16,000 feet) miss the -limit of perpetual snow and are snow-covered only a few months each -year.</p> - -<p>In taking observations on the snowline along the seventy-third<a name="page_277" id="page_277"></a> meridian -I was fortunate enough to have a topographer the heights of whose -stations enabled me to correct the readings of my aneroid barometer -whenever these were taken off the line of traverse. Furthermore, the -greater height of the passes—15,000 to 17,600 feet—brought me more -frequently above the snowline than had been the case in Bolivia and -Chile. More detailed observations were made, therefore, not only upon -the elevation of the snowline from range to range, but also upon the -degree of canting of the snowline on a given range. Studies were also -made on the effect of the outline of the valleys upon the extent of the -glaciers, the influence on the position of the snowline of mass -elevation, precipitation, and cloudiness.</p> - -<p>Snow first appears at 14,500 feet (4,320 m.) on the eastern flanks of -the Cordillera Vilcapampa, in 13° south latitude. East of this group of -ridges and peaks as far as the extreme eastern border of the mountain -belt, fifty miles distant, the elevations decrease rapidly to 10,000 -feet and lower, with snow remaining on exceptionally high peaks from a -few hours to a few months. In the winter season snow falls now and then -as low as 11,500 feet, as in the valley below Vilcabamba pueblo in early -September, 1911, though it vanishes like mist with the appearance of the -sun or the warm up-valley winds from the forest. Storms gather daily -about the mountain summits and replenish the perpetual snow above 15,000 -feet. In the first pass above Puquiura we encountered heavy snow banks -on the northeastern side a hundred feet below the pass (14,500 feet), -but on the southwestern or leeward side it is five hundred feet lower. -This distribution is explained by the lesser insolation on the -southwestern side, the immediate drifting of the clouds from the -windward to the leeward slopes, and to the mutual intensification of -cause and effect by topographic changes such as the extension of -collecting basins and the steeping of the slopes overlooking them with a -corresponding increase in the duration of shade.</p> - -<p>It is well known that with increase of elevation and therefore of the -rarity of the air there is less absorption of the sun’s radiant energy, -and a corresponding increase in the degree of insolation.<a name="page_278" id="page_278"></a> It follows, -therefore, that at high altitudes the contrasts between sun and shade -temperatures will increase. Frankland<a name="FNanchor_56_56" id="FNanchor_56_56"></a><a href="#Footnote_56_56" class="fnanchor">[56]</a> has shown that the increase -may run as high as 500 per cent between 100 to 10,000 feet above the -sea. I have noted a fall of temperature of 15° F. in six minutes, due to -the obscuring of the sun by cloud at an elevation of 16,000 feet above -Huichihua in the Central Ranges of Peru. Since the sun shines -approximately half the time in the snow-covered portions of the -mountains and since the tropical Andes are of necessity snow-covered -only at lofty elevations, this contrast between shade and sun -temperatures is by far the most powerful factor influencing differences -in elevation of the snowline in Peru.</p> - -<p>To the drifting of the fallen snow is commonly ascribed a large portion -of this contrast. I have yet to see any evidence of its action near the -snowline, though I have often observed it, especially under a high wind -in the early morning hours at considerable elevations above the -snowline, as at the summits of lofty peaks. It appears that the lower -ranges bearing but a limited amount of snow are not subject to drifting -because of the wetness of the snow, and the fact that it is compacted by -occasional rains and hail storms. Only the drier snow at higher -elevations and under stronger winds can be effectively dislodged.</p> - -<p>The effect of unequal distribution of precipitation on the windward and -leeward slopes of a mountain range is in general to depress the snowline -on the windward slopes where the greater amount falls, but this may be -offset in high altitudes by temperature contrasts as in the westward -trending Cordillera Vilcapampa, where north and south slopes are in -opposition. If the Cordillera Vilcapampa ran north and south we should -have the windward and leeward slopes equally exposed to the sun and the -snowline would lie at a lower elevation on the eastern side. Among all -the ranges the slopes have decreasing precipitation to the leeward, that -is, westerly. The second and third passes, between Arma and Choquetira, -are snow-free (though their elevations equal those of<a name="page_279" id="page_279"></a> the first pass) -because they are to leeward of the border range, hence receive less -precipitation. The depressive effect of increased precipitation on the -snowline is represented by A-B, <a href="#fig_184">184</a> ; in an individual range the -effect of heavier precipitation may be offset by temperature contrasts -between shady and sunny slopes, as shown by the line a-b in the same -figure.</p> - -<p>The degree of canting of the snowline on opposite slopes of the -Cordillera Vilcapampa varies between 5° and 12°, the higher value being -represented four hours southwest of Arma on the Choquetira trail, -looking northeast. A general view of the Cordillera looking east at this -point (<a href="#fig_186">Fig. 186</a>), shows the appearance of the snowline as one looks -along the flanks of the range. In detail the snowline is further -complicated by topography and varying insolation, each spur having a -snow-clad and snow-free aspect as shown in the last figure. The degree -of difference on these minor slopes may even exceed the difference -between opposite aspects of the range in which they occur.</p> - -<p><a name="fig_184" id="fig_184"></a></p> - -<div class="figright" style="width: 166px;"> -<a href="images/ill_page_279_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_279_sml.jpg" width="116" height="34" alt="Fig. 184—To illustrate the canting of the snowline. -A-B is the snowline depressed toward the north (right) in response to -heavier precipitation. The line a-b represents a depression in the -opposite direction due to the different degree of insolation on the -northern (sunny) and southern (shady) slopes." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 184—To illustrate the canting of the snowline. -A-B is the snowline depressed toward the north (right) in response to -heavier precipitation. The line a-b represents a depression in the -opposite direction due to the different degree of insolation on the -northern (sunny) and southern (shady) slopes.</p> -</div> - -<p>To these diversifying influences must be added the effect of warm -up-valley winds that precede the regular afternoon snow squalls and that -melt the latest fall of snow to exceptionally high elevations on both -the valley floor and the spurs against which they impinge. The influence -of the warmer air current is notably confined to the heads of those -master valleys that run down the wind, as in the valley heading at the -first pass, Cordillera Vilcapampa, and at the heads of the many valleys -terminating at the passes of the Maritime Cordillera. Elsewhere the -winds are dissipated in complex systems of minor valleys and their -effect is too well distributed to be recognized.</p> - -<p>It is clear from the conditions of the problem as outlined on preceding -pages that the amount of canting may be expressed in feet of difference -of the snowline on opposite sides of a range or<a name="page_280" id="page_280"></a> in degrees. The former -method has, heretofore, been employed. It is proposed that this method -should be abolished and degrees substituted, on the following grounds: -Let <i>A</i> and <i>B</i>, <a href="#fig_190">190</a> , represent two mountain masses of unequal area -and unequal elevation. Let the opposite ends of the snowlines of both -figures lie 1,000 feet apart as between the windward and leeward sides -of a broad cordillera (A), or as between the relatively sunnier and -relatively shadier slopes of individual mountains or narrow ranges in -high latitudes or high altitudes (B). With increasing elevation there is -increasing contrast between temperatures in sunshine and in shade, hence -a greater degree of canting (B). Tending toward a still greater degree -of contrast is the effect of the differences in the amounts of snowy -precipitation, which are always more marked on an isolated and lofty -mountain summit than upon a broad mountain mass (1) because in the -former there is a very restricted area where snow may accumulate, and -(2) because with increase of elevation there is a rapid and differential -decrease in both the rate of adiabatic cooling and the amount of water -vapor; hence the snow-producing forces are more quickly dissipated.</p> - -<p><a name="fig_185" id="fig_185"></a></p> - -<div class="figleft" style="width: 158px;"> -<a href="images/ill_page_280_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_280_sml.jpg" width="108" height="140" alt="Fig. 185—Glacial features in the Peruvian Andes near -Arequipa. Sketched from a railway train, July, 1911. The horizontal -broken lines represent the lower limit of light snow during late June, -1911. There is a fine succession of moraines in U-shaped valleys in all -the mountains of the Arequipa region. A represents a part of Chacchani -northwest of Arequipa; B is looking south by east at the northwest end -of Chacchani near Pampa de Arrieros; C also shows the northwest end of -Chacchani from a more distant point." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 185—Glacial features in the Peruvian Andes near -Arequipa. Sketched from a railway train, July, 1911. The horizontal -broken lines represent the lower limit of light snow during late June, -1911. There is a fine succession of moraines in U-shaped valleys in all -the mountains of the Arequipa region. A represents a part of Chacchani -northwest of Arequipa; B is looking south by east at the northwest end -of Chacchani near Pampa de Arrieros; C also shows the northwest end of -Chacchani from a more distant point.</p> -</div> - -<p><a name="fig_186" id="fig_186"></a></p> -<p><a name="fig_187" id="fig_187"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_280a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_280a_sml.jpg" width="213" height="327" alt="Fig. 186—Canted snowline in the Cordillera Vilcapampa -between Arma and Choquetira. Looking east from 13,500 feet." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 186—Canted snowline in the Cordillera Vilcapampa -between Arma and Choquetira. Looking east from 13,500 feet.</p> - -<p class="caption"><span class="smcap">Fig. 187</span>—Glacial topography between Lambrama and -Antabamba in the Central Ranges. A recent fall of snow covers the -foreground. The glaciers are now almost extinct and their action is -confined to the deepening and steepening of the cirques at the valley -heads.</p> -</div> - -<p style="clear:both;"><a name="fig_188" id="fig_188"></a></p> - -<p><a name="fig_189" id="fig_189"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_280b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_280b_sml.jpg" width="219" height="326" alt="Fig. 188—Asymmetrical peaks in the Central Ranges -between Antabamba and Lambrama. The snow-filled hollows in the -photograph face away from the sun—that is, south—and have retained -snow since the glacial epoch; while the northern slopes are snow-free. -There is no true glacial ice and the continued cirque recession is due -to nivation." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 188—Asymmetrical peaks in the Central Ranges -between Antabamba and Lambrama. The snow-filled hollows in the -photograph face away from the sun—that is, south—and have retained -snow since the glacial epoch; while the northern slopes are snow-free. -There is no true glacial ice and the continued cirque recession is due -to nivation.</p> - -<p class="caption"><span class="smcap">Fig. 189</span>—Glacial topography north of the divide on the -seventy-third meridian. Maritime Cordillera. Looking downstream at an -elevation of 16,500 feet (5,030 m.).</p> -</div> - -<p>Furthermore, the leeward side of a lofty mountain not only receives much -less snow proportionally than the leeward side of<a name="page_281" id="page_281"></a> a lower mountain, -but also loses it faster on account of the smaller extent of surface -upon which it is disposed and the proportionally larger extent of -counteractive, snow-free surface about it. Among the volcanoes of -Ecuador are many that show differences of 500 feet in snowline elevation -on windward and leeward (east) slopes and some, as for example -Chimborazo, that exhibit differences of 1,000 feet. The latter figure -also expresses the differences in the broad Cordillera Vilcapampa and in -the Maritime Cordillera, though the <i>rate</i> of canting as expressed in -degrees is much greater in the case of the western mountains.</p> - -<p><a name="fig_190" id="fig_190"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_281_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_281_sml.jpg" width="214" height="49" alt="Fig. 190—To illustrate the difference in the degree of -canting of the snowline on large and on small mountain masses." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 190—To illustrate the difference in the degree of -canting of the snowline on large and on small mountain masses.</p> -</div> - -<p>The advantages of the proposed method of indicating the degree of -canting of the snowline lie in the possibility thus afforded of -ultimately separating and expressing quantitatively the various factors -that affect the position of the line. In the Cordillera Vilcapampa, for -example, the dominant canting force is the difference between sun and -shade temperatures, while in the volcanoes of Ecuador, where -<i>symmetrical volcanoes, almost on the equator, have equal insolation on -all aspects</i> and the temperature contrasts are reduced to a minimum—the -differences are owing chiefly to varying exposure to the winds. The -elusive factors in the comparison are related to the differences in area -and in elevation.</p> - -<p>The value of arriving finally at close snowline analyses grows out of -(1) the possibility of snowline changes in short cycles and (2) -uncertainty of arriving by existing methods at the snowline of the -glacial period, whose importance is fundamental in refined physiographic -studies in glaciated regions with a complex topography. To show the -application of the latter point we shall now<a name="page_282" id="page_282"></a> attempt to determine the -snowline of the glacial period in the belt of country along the route of -the Expedition.</p> - -<p>In the group of peaks shown in <a href="#fig_188">188</a> between Lambrama and Antabamba, -the elevation of the snowline varies from 16,000 to 17,000 feet -(4,880-5,180 m.), depending on the topography and the exposure. The -determination of the limit of perpetual snow was here, as elsewhere -along the seventy-third meridian, based upon evidences of nivation. It -will be observed in <a href="#fig_191">191</a> that just under the snow banks to the left -of the center are streams of rock waste which head in the snow. Their -size is roughly proportional to the size of the snow banks, and, -furthermore, they are not found on snow-free slopes. From these facts it -is concluded that they represent the waste products of snow erosion or -nivation, just as the hollows in which the snow lies represent the -topographic products of nivation. On account of the seasonal and annual -variation in precipitation and temperature—hence in the elevation of -the snowline—it is often difficult to make a correct snowline -observation based upon depth and <i>apparent</i> permanence. Different -observers report great changes in the snowline in short intervals, -changes not explained by instrumental variations, since they are -referred to topographic features. It appears to be impossible to rely -upon present records for small changes possibly related to minor -climatic cycles because of a lack of standardization of observations.</p> - -<p>Nothing in the world seems simpler at first sight than an observation on -the elevation of the snowline. Yet it can be demonstrated that large -numbers of observers have merely noted the position of temporary snow. -It is strongly urged that evidences of nivation serve henceforth as -proof of permanent snow and that photographic records be kept for -comparison. In this way measurements of changes in the level of the -snowline may be accurately made and the snow cover used as a climatic -gauge.</p> - -<p>Farther west in the Maritime Cordillera, the snowline rises to 18,000 -feet on the northern slopes of the mountains and to 17,000 feet on the -southern slopes. The top of the pass above Cotahuasi, 17,600 feet (5,360 -m.), was snow-free in October, 1911, but the<a name="page_283" id="page_283"></a> snow extended 500 feet -lower on the southern slope. The degree of canting is extraordinary at -this point, single volcanoes only 1,500 to 2,000 feet above the general -level and with bases but a few miles in circumference exhibit a thousand -feet of difference in the snowline upon northern and southern aspects. -This is to be attributed no less to the extreme elevation of the snow -(and, therefore, stronger contrasts of shade and sun temperatures) than -to the extreme aridity of the region and the high daytime temperatures. -The aridity is a factor, since heavy snowfall means a lengthening of the -period of precipitation in which a cloud cover shuts out the sun and a -shortening of the period of insolation and melting.</p> - -<p>Contrasts between shade and sun temperatures increase with altitude but -their effects also increase in <i>time</i>. Of two volcanoes of equal size -and both 20,000 feet above sea level, that one will show the greater -degree of canting that is longer exposed to the sun. The high daytime -temperature is a factor, since it tends to remove the thinnest snow, -which also falls in this case on the side receiving the greatest amount -of heat from the sun. The high daytime temperature is phenomenal in this -region, and is owing to the great extent of snow-free land at high -elevations and yet below the snowline, and to the general absence of -clouds and the thinness of vegetation.</p> - -<p>On approach to the western coast the snowline descends again to 17,500 -feet on Coropuna. There are three chief reasons for this condition. -First, the well-watered Majes Valley is deeply incised almost to the -foot of Coropuna, above Chuquibamba, and gives the daily strong sea -breeze easy access to the mountain. Second, the Coast Range is not only -low at the mouth of the Majes Valley, but also is cut squarely across by -the valley itself, so that heavy fogs and cloud sweep inland nightly and -at times completely cover both valley and desert for an hour after -sunrise. Although these yield no moisture to the desert or the valley -floor except such as is mechanically collected, yet they do increase the -precipitation upon the higher elevations at the valley head.</p> - -<div class="figcenter"> -<a href="images/ill_page_283a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_283a_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_283a_sml.jpg" width="381" height="416" alt="THE YALE PERUVIAN EXPEDITION OF 1911 -HIRAM BINGHAM DIRECTOR -ANTABAMBA QUADRANGLE" /> -</div> - -<p>A third factor is the size of Coropuna itself. The mountain<a name="page_284" id="page_284"></a> is not a -simple volcano but a composite cone with five main summits reaching well -above the snowline, the highest to an elevation of 21,703 feet (6,615 -m.). It measures about 20 miles (32 km.) in circumference at the -snowline and 45 miles (72 km.) at its base (measuring at the foot of the -steeper portion), and stands upon a great tributary lava plateau from -15,000 to 17,000 feet above sea level. Compared with El Misti, at -Arequipa, its volume is three times as great, its height two thousand -feet more, and its access to ocean winds at least thirty per cent more -favorable. El Misti, 19,200 feet (5,855 m.) has snow down as far as -16,000 feet in the wet season and rarely to 14,000 feet, though by -sunset a fall of snow may almost disappear whose lower limit at sunrise -was 16,000 feet. Snow may accumulate several thousand feet below the -summit during the wet season, and in such quantities as to require -almost the whole of the ensuing dry season (March to December) for its -melting. Northward of El Misti is the massive and extended range, -Chachani, 20,000 feet (6,100 m.) high; on the opposite side is the -shorter range called Pichu-Pichu. Snow lies throughout the year on both -these ranges, but in exceptional seasons it nearly disappears from -Chachani and wholly disappears from Pichu-Pichu, so that the snowline -then rises to 20,000 feet. It is considered that the mean of a series of -years would give a value between 17,000 and 18,000 feet for the snowline -on all the great mountains of the Arequipa region.<a name="FNanchor_57_57" id="FNanchor_57_57"></a><a href="#Footnote_57_57" class="fnanchor">[57]</a> This would, -however, include what is known to be temporary snow; the limit of -“perpetual†snow, or the true snowline, appears to lie about 19,000 feet -on Chachani and <i>above</i> El Misti, say 19,500 feet. It is also above the -crest of Pichu-Pichu. The snowline, therefore, appears to rise a -thousand feet from Coropuna to El Misti, owing chiefly to the poorer -exposure of the latter to the sources of snowy precipitation.</p> - -<p>It may also be noted that the effect of the easy access of the ocean -winds in the Coropuna region is also seen in the increasing amount of -vegetation which appears in the most favorable situations.<a name="page_285" id="page_285"></a> Thus, along -the Salamanca trail only a few miles from the base of Coropuna are a few -square kilometers of <i>quenigo</i> woodland generally found in the cloud -belt at high altitudes; for example, at 14,000 feet above Lambrama and -at 9,000 feet on the slope below Incahuasi, east of Pasaje. The greater -part of the growth is disposed over hill slopes and on low ridges and -valley walls. It is, therefore, clearly unrelated as a whole to the -greater amount of ground-water with which a part is associated, as along -the valley floors of the streams that head in the belt of perpetual -snow. The appearance of this growth is striking after days of travel -over the barren, clinkery lava plateau to eastward that has a less -favorable exposure. The <i>quenigo</i> forest, so-called, is of the greatest -economic value in a land so desolate as the vast arid and semi-arid -mountain of western Peru. Every passing traveler lays in a stock of -fire-wood as he rests his beasts at noonday; and long journeys are made -to these curious woodlands from both Salamanca and Chuquibamba to gather -fuel for the people of the towns.</p> - -<h4>NIVATION</h4> - -<p>The process of nivation, or snow erosion, does not always produce -visible effects. It may be so feeble as to make no impression upon very -resistant rock where the snow-fall is light and the declivity low. -Ablation may in such a case account for almost the whole of the snow -removed. On strong and topographically varied slopes where the snow is -concentrated in headwater alcoves, there is a more pronounced downward -movement of the snow masses with more prominent effects both of erosion -beneath the snow and of accumulation at the border of the snow. In such -cases the limit of perpetual snow may be almost as definitely known as -the limit of a glacier. Like glaciers these more powerful snow masses -change their limits in response to regional changes in precipitation, -temperature, or both. It would at first sight appear impossible to -distinguish between these changes through the results of nivation. Yet -in at least a few cases it may be as readily determined as the past -limits of glaciers are inferred <a name="page_286" id="page_286"></a>from the terminal moraines, still -intact, that cross the valley floors far below the present limits of the -ice.</p> - -<p>In discussing the process of nivation it is necessary to assume a -sliding movement on the part of the snow, though it is a condition in -Matthes’ original problem in which the nivation idea was introduced that -the snow masses remain stationary. It is believed, however, that -Matthes’ valuable observations and conclusions really involve but half -the problem of nivation; or at the most but one of two phases of it. He -has adequately shown the manner in which that phase of nivation is -expressed which we find <i>at the border of the snow</i>. Of the action -<i>beneath</i> the snow he says merely: “Owing to the frequent oscillations -of the edge and the successive exposure of the different parts of the -site to frost action, the area thus affected will have no well-defined -boundaries. The more accentuated slopes will pass insensibly into the -flatter ones, and the general tendency will be to give the drift site a -cross section of smoothly curved outline and ordinarily concave.â€<a name="FNanchor_58_58" id="FNanchor_58_58"></a><a href="#Footnote_58_58" class="fnanchor">[58]</a></p> - -<p>From observations on the effects of nivation in valleys, Matthes further -concludes that “on a grade of about 12 per cent ... névé must attain a -thickness of at least 125 feet in order that it may have motion,â€<a name="FNanchor_59_59" id="FNanchor_59_59"></a><a href="#Footnote_59_59" class="fnanchor">[59]</a> -though as a result of the different line of observations Hobbs -concludes<a name="FNanchor_60_60" id="FNanchor_60_60"></a><a href="#Footnote_60_60" class="fnanchor">[60]</a> that a somewhat greater thickness is required.</p> - -<p style="clear:both;"><a name="fig_192" id="fig_192"></a></p> -<p><a name="fig_191" id="fig_191"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_286a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_286a_sml.jpg" width="217" height="331" alt="Fig. 191—The “pocked†surface characteristically -developed in the zone of light nivation. Compare with Fig. 194, showing -the effects of heavy nivation." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 191—The “pocked†surface characteristically -developed in the zone of light nivation. Compare with Fig. 194, showing -the effects of heavy nivation.</p> - -<p class="caption"><span class="smcap">Fig. 192</span>—Steep cirque walls and valleys head in the -Central Ranges between Lambrama and Chuquibambilla. The snow is here a -vigorous agent in transporting talus material and soil from all the -upper slopes down to the foot of the cirque wall.</p> -</div> - -<p>The snow cover in tropical mountains offers a number of solid advantages -in this connection. Its limits, especially on the Cordillera Vilcapampa, -on the eastern border of the Andes, are subject to <i>small seasonal -oscillations</i> and the edge of the “perpetual†snow is easily determined. -Furthermore, it is known from the comparatively “fixed quality of -tropical climate,†as Humboldt put it, that the variations of the -snowline in a period of years do not exceed rather narrow limits. In -mid-latitudes on the contrary there is an extraordinary shifting of the -margin of the snow<a name="page_287" id="page_287"></a> cover, and a correspondingly wide distribution of -the feeble effects of nivation.</p> - -<p><a name="fig_193" id="fig_193"></a></p> - -<p><a name="fig_194" id="fig_194"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_286b_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_286b_sml.jpg" width="214" height="326" alt="Fig. 193—Panta Mountain and its glacier system. The -talus-covered mass in the center (B) is a terminal moraine topped by the -dirt-stained glacier that descends from the crest. The separate glaciers -were formerly united to form a huge ice tongue that truncated the -lateral spurs and flattened the valley floor. One of its former stages -is shown by the terminal moraine in the middle distance, breached by a -stream, and impounding a lake not visible from this point of view." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 193—Panta Mountain and its glacier system. The -talus-covered mass in the center (B) is a terminal moraine topped by the -dirt-stained glacier that descends from the crest. The separate glaciers -were formerly united to form a huge ice tongue that truncated the -lateral spurs and flattened the valley floor. One of its former stages -is shown by the terminal moraine in the middle distance, breached by a -stream, and impounding a lake not visible from this point of view.</p> - -<p class="caption"><span class="smcap">Fig. 194</span>—Recessed southern slopes of volcanoes whose -northern slopes are practically without glacial modifications. Summit of -the lava plateau, Maritime Cordillera, western Peru, between Antabamba -and Cotahuasi.</p> -</div> - -<p>Test cases are presented in Figs. 191, 192, and 193, Cordillera -Vilcapampa, for the determination of the fact of the movement of the -snow long before it has reached the thickness Matthes or Hobbs believes -necessary for a movement of translation to begin. <a href="#fig_191">191</a> shows snow -masses occupying pockets on the slope of a ridge that was never covered -with ice. Past glacial action with its complicating effects is, -therefore, excluded and we have to deal with snow action pure and -simple. The pre-glacial surface with smoothly contoured slopes is -recessed in a noteworthy way from the ridge crest to the snowline of the -glacial period at least a thousand feet lower. The recesses of the -figure are peculiar in that not even the largest of them involve the -entire surface from top to bottom; they are of small size and are -scattered over the entire slope. This is believed to be due to the fact -that they represent the limits of variations of the snowline in short -cycles. Below them as far as the snowline of the glacial period are -larger recesses, some of which are terminated by masses of waste as -extensive as the neighboring moraines, but disposed in irregular -scallops along the borders of the ridges or mountain slopes in which the -recesses have been found.</p> - -<p>The material accumulated at the lower limit of the snow cover of the -glacial period was derived from two sources: (1) from slopes and cliffs -overlooking the snow, (2) from beneath the snow by a process akin to ice -plucking and abrasion. The first process is well known and resembles the -shedding of waste upon a valley glacier or a névé field from the -bordering cliffs and slopes. Material derived in this manner in many -places rolls down a long incline of snow and comes to rest at the foot -of it as a fringe of talus. The snow is in this case but a substitute -for a normal mass of talus. The second process produces its most clearly -recognizable effects on slopes exceeding a declivity of 20°; and upon -30° and 40° slopes its action is as well-defined as true glacial action -which it imitates. It appears to operate in its simplest form as if -independent of the mass of the snow, small and large snow<a name="page_288" id="page_288"></a> patches -showing essentially the same results. This is the reverse of Matthes’ -conclusion, since he says that though the minimum thickness “must vary -inversely with the percentage of the grade,†“the influence of the grade -is inconsiderable,†and that the law of variation must depend upon -additional observation.<a name="FNanchor_61_61" id="FNanchor_61_61"></a><a href="#Footnote_61_61" class="fnanchor">[61]</a></p> - -<p>Let us examine a number of details and the argument based upon them and -see if it is not possible to frame a satisfactory law of variation.</p> - -<p>In <a href="#fig_193">193</a> the chief conditions of the problem are set forth. Forward -from the right-hand peak are snow masses descending to the head of a -talus (<i>A</i>) whose outlines are clearly defined by freshly fallen snow. -At (<i>B</i>) is a glacier whose tributaries descend the middle and left -slopes of the picture after making a descent from slopes several -thousand feet higher and not visible in this view. The line beneath the -glacier marks the top of the moraine it has built up. Moraines farther -down valley show a former greater extent of the glacier. Clearly the -talus material at (<i>A</i>) was accumulated after the ice had retreated to -its present position. It will be readily seen from an inspection of the -photograph that the total amount of material at (<i>A</i>) is an appreciable -fraction of that in the moraine. The ratio appears to be about 1:8 or -1:10. I have estimated that the total area of snow-free surface about -the snowfields of the one is to that of the other as 2:3. The gradients -are roughly equivalent, but the volume of snow in the one case is but a -small fraction of that in the other. It will be seen that the snow -masses have recessed the mountain slopes at <i>A</i> and formed deep hollows -and that the hollowing action appears to be most effective where the -snow is thickest.</p> - -<p>Summarizing, we note first, that the roughly equivalent factors are -gradient and amount of snow-free surface; second, that the unequal -factors are (a) accumulated waste, (b) degree of recessing, and (c) the -degree of compacting of snow into ice and a corresponding difference in -the character of the glacial agent, and (d) the extent of the snow -cover. The direct and important<a name="page_289" id="page_289"></a> relation of the first two unequal -factors to the third scarcely need be pointed out.</p> - -<p>We have then an inequality in amount of accumulated material to be -explained by either an inequality in the extent of the snow and -therefore an inequality of snow action, or an inequality due to the -presence of ice in one valley and not in the other, or by both. It is at -once clear that if ice is absent above (<i>A</i>) and the mountain slopes are -recessed that snow action is responsible for it. It is also recognized -that whatever rate of denudation be assigned to the snow-free surfaces -this rate must be exceeded by the rate of snow action, else the -inequalities of slope would be decreased rather than increased. The -accumulated material at (<i>A</i>) is, therefore, partly but not chiefly due -to denudation of snow-free surfaces. It is due chiefly to <i>erosion</i> -beneath the snow. Nor can it be argued that the hollows now occupied by -snow were formed at some past time when ice not snow lay in them. They -are not ice-made hollows for they are on a steep spur above the limits -of ice action even in the glacial period. Any past action is, therefore, -represented here in <i>kind</i> by present action, though there would be -differences in <i>degree</i> because the heavier snows of the past were -displaced by the lighter snows of today.</p> - -<p>While it appears that the case presents clear proof of degradation by -snow it is not so clear how these results were accomplished. Real -abrasion on a large scale as in bowlder-shod glaciers is ruled out, -since glacial striæ are wholly absent from nivated surfaces according to -both Matthes’ observations and my own. Yet all nivated surfaces have -very distinctive qualities, delicately organized slopes which show a -marked change from any original condition related to water-carving. In -the absence of striæ, the general absence of all but a thin coating of -waste <i>even in rock hollows</i>, and the accumulation of waste up to -bowlders in size at the lower edge of the nivated zone, I conclude that -compacted snow or névé of sufficient thickness and gradient may actually -pluck rock outcrops in the same manner though not at the rate which ice -exhibits. That the products of nivation may be bowlders as well as fine -mud would seem clearly to follow increase in effectiveness,<a name="page_290" id="page_290"></a> due to -increase in amount of the accumulated snow; that bowlders are actually -transported by snow is also shown by their presence on the lower margins -of nivated tracts.</p> - -<p>Our argument may be made clearer by reference to the observed action of -snow in a particular valley. Snow is shed from the higher, steeper -slopes to the lower slopes and eventually accumulates to a marked degree -on the bottoms of the depressions, whence it is avalanched down valley -over a series of irregular steps on the valley floor. An avalanche takes -place through the breaking of a section of snow just as an iceberg -breaks off the end of a tide-water glacier. Evidently there must be -pressure from behind which crowds the snow forward and precipitates it -to a lower level.</p> - -<p>As a snow mass falls it not only becomes more consolidated, beginning at -the plane of impact, but also gives a shock to the mass upon which it -falls that either starts it in motion or accelerates its rate of motion. -The action must therefore be accompanied by a drag upon the floor and if -the rock be close-jointed and the blocks, defined by the joint planes, -small enough, they will be transported. Since snow is not so compact as -ice and permits included blocks easily to adjust themselves to new -resistances, we should expect the detached blocks included in the snow -to change their position constantly and to form irregular scratches, but -not parallel striæ of the sort confidently attributed to stone-shod ice.</p> - -<p>It is to the plasticity of snow that we may look for an explanation of -the smooth-contoured appearance of the landscape in the foreground of -Fig. 135. The smoothly curved lines are best developed where the entire -surface was covered with snow, as in mid-elevations in the larger -snowfields. At higher elevations, where the relief is sharper, the snow -is shed from the steeper declivities and collected in the minor basins -and valley heads, where its action tends to smooth a floor of limited -area, while snow-free surfaces retain all their original irregularities -of form or are actually sharpened.</p> - -<p>The degree of effectiveness of snow and névé action may be estimated -from the reversed slopes now marked by ponds or small<a name="page_291" id="page_291"></a> marshy tracts -scattered throughout the former névé fields, and the many niched -hollows. They are developed above Pampaconas in an admirable manner, -though their most perfect and general development is in the summit belt -of the Cordillera Vilcapampa between Arma and Choquetira, <a href="#fig_135">135</a> . It -is notable in <i>all</i> cases where nivation was associated with the work of -valley glaciers that the rounded nivated slopes break rather sharply -with the steep slopes that define an inner valley, whose form takes on -the flat floor and under-cut marginal walls normal to valley glaciation.</p> - -<p>A classification of numerous observations in the Cordillera Vilcapampa -and in the Maritime Cordillera between Lambrama and Antabamba may now be -presented as the basis for a tentative expression of the law of -variation respecting snow motion. The statement of the law should be -prefaced by the remark that thorough checking is required under a wider -range of conditions before we accept the law as final. Near the lower -border of the snow where rain and hail and alternate freezing and -thawing take place, the snow is compacted even though but fifteen to -twenty feet thick, and appears to have a down-grade movement and to -exercise a slight drag upon its floor when the gradient does not fall -below 20°. Distinct evidences of nivation were observed on slopes with a -declivity of 5° near summit areas of past glacial action, where the snow -did not have an opportunity to be alternately frozen and thawed.</p> - -<p>The <i>thickness</i> of the former snow cover could, however, not be -accurately determined, but was estimated from the topographic -surroundings to have been at least several hundred feet. Upon a 40° -slope a snow mass 50 feet thick was observed to be breaking off at a -cliff-face along the entire cross-section as if impelled forward by -thrust, and to be carrying a small amount of waste—enough distinctly to -discolor the lowermost layers—which was shed upon the snowy masses -below. With increase in the degree of compactness of the snow at -successively lower elevations along a line of snow discharge, gradients -down to 25° were still observed to carry strongly crevassed, waste-laden -snow down to the melting border. It appeared from the clear evidences of -vigorous<a name="page_292" id="page_292"></a> action—the accumulation of waste, the strong crevassing, the -stream-like character of the discharging snow, and the pronounced -topographic depression in which it lay—that much flatter gradients -would serve, possibly not more than 15°, for a snow mass 150 feet wide, -30 to 40 feet thick, and serving as the outlet for a set of tributary -slopes about a square mile in area and with declivities ranging from -small precipices to slopes of 30°.</p> - -<p>We may say, therefore, that the factors affecting the rate of motion are -(1) thickness, (2) degree of compactness, (3) diurnal temperature -changes, and (4) gradient. Among these, diurnal temperature changes -operate indirectly by making the snow more compact and also by inducing -motion directly. At higher elevations above the snowline, temperature -changes play a decreasingly important part. The thickness required -varies inversely as the gradient, and upon a 20° slope is 20 feet for -wet and compact snow subjected to alternate freezing and thawing. For -dry snow masses above the zone of effective diurnal temperature changes, -an increasing gradient is required. With a gradient of 40°, less than 50 -feet of snow will move <i>en masse</i> if moderately compacted under its own -weight; if further compacted by impact of falling masses from above, the -required thickness may diminish to 40 feet and the required declivity to -15°. The gradient may decrease to 0° or actually be reversed and motion -still continue provided the compacting snow approach true névé or even -glacier ice as a limit.</p> - -<p>From the sharp topographic break between the truly glaciated portions of -the valley in regions subjected to temporary glaciation, it is concluded -that the eroding power of the moving mass is suddenly increased at the -point where névé is finally transformed into true ice. This -transformation must be assumed to take place suddenly to account for so -sudden a change of function as the topographic break requires. Below the -point at which the transformation occurs the motion takes place under a -new set of conditions whose laws have already been formulated by -students of glaciology.</p> - -<p><a name="fig_195" id="fig_195"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_293_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_293_sml.jpg" width="215" height="155" alt="Fig. 195—Curve of snow motion. Based on many -observations of snow motion to show minimum thickness of snow required -to move on a given gradient. Figures on the left represent thickness of -snow in feet. The degrees represent the gradient of the surface. The -gradients have been run in sequence down to 0° for the sake of -completing the accompanying discussion. Obviously no glacially -unmodified valley in a region of mountainous relief would start with so -low a gradient, though glacial action would soon bring it into -existence. Between +5° and -5° the curve is based on the gradients of -nivated surfaces." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 195—Curve of snow motion. Based on many -observations of snow motion to show minimum thickness of snow required -to move on a given gradient. Figures on the left represent thickness of -snow in feet. The degrees represent the gradient of the surface. The -gradients have been run in sequence down to 0° for the sake of -completing the accompanying discussion. Obviously no glacially -unmodified valley in a region of mountainous relief would start with so -low a gradient, though glacial action would soon bring it into -existence. Between +5° and -5° the curve is based on the gradients of -nivated surfaces.</p> -</div> - -<p>The foregoing readings of gradient and depth of snow are<a name="page_293" id="page_293"></a> typical of a -large number which were made in the Peruvian Andes and which have served -as the basis of <a href="#fig_195">195</a> . It will be observed that between 15° and 20° -there is a marked change of function and again between +5° and -5° -declivity, giving a double reversed curve. The meaning of the change -between 15° and 20° is inferred to be that, with gradients over 20°, -snow cannot wholly resist gravity in the presence of diurnal temperature -changes across the freezing point and occasional snow or hail storms. -With increase of thickness compacting appears to progress so rapidly as -to permit the transfer of thrust for short distances before absorption -of thrust takes place in the displaced snow. At 250 feet thorough -compacting appears to take place, enabling the snow to move out under -its own weight on even the faintest slopes; while,<a name="page_294" id="page_294"></a> with a thickness -still greater, the resulting névé may actually be forced up slight -inclines whose declivity appears to approach 5° as a limit. I have -nowhere been able to find in truly nivated areas reversed curves -exceeding 5°, though it should be added that depressions whose leeward -slopes were reversed to 2° and 3° are fairly common. If the curve were -continued we should undoubtedly find it again turning to the left at the -point where the thickness of the snow results in the transformation of -snow to ice. From the sharp topographic break observed to occur in a -narrow belt between the névé and the ice, it is inferred that the -erosive power of the névé is to that of the ice as 2:4 or 1:5 <i>for equal -areas</i>; and that reversed slopes of a declivity of 10° to 15° may be -formed by glaciers is well known. Precisely what thickness of snow or -névé is necessary and what physical conditions effect its transformation -into ice are problems not included in the main theme of this chapter.</p> - -<p>It is important that the proposed curve of snow motion under minimum -conditions be tested under a large variety of circumstances. It may -possibly be found that each climatic region requires its special -modifications. In tropical mountains the sudden alternations of freezing -and thawing may effect such a high degree of compactness in the snow -that lower minimum gradients are required than in the case of -mid-latitude mountains where the perpetual snow of the high and cold -situations is compacted through its own weight. Observations of the -character introduced here are still unattainable, however. It is hoped -that they will rapidly increase as their significance becomes apparent; -and that they have high significance the striking nature of the curve of -motion seems clearly to establish.</p> - -<h4>BERGSCHRUNDS AND CIRQUES</h4> - -<p>The facts brought out by the curve of snow-motion (<a href="#fig_195">Fig. 195</a>) have an -immediate bearing on the development of cirques, whose precise mode of -origin and development have long been in doubt. Without reviewing the -arguments upon which the various hypotheses rest, we shall begin at once -with the strongest explanation<a name="page_295" id="page_295"></a>—W. D. Johnson’s famous bergschrund -hypothesis. The critical condition of this hypothesis is the diurnal -migration across the freezing point of the air temperature at the bottom -of the schrund. Alternate freezing and thawing of the water in the -joints of the rock to which the schrund leads, exercise a quarrying -effect upon the rock and, since this effect is assumed to take place at -the foot of the cirque, the result is a steady retreat of the steep -cirque wall through basal sapping.</p> - -<p>While Johnson’s hypothesis has gained wide acceptance and is by many -regarded as the final solution of the cirque problem it has several -weaknesses in its present form. In fact, I believe it is but one of two -factors of equal importance. In the first place, as A. C. Andrews<a name="FNanchor_62_62" id="FNanchor_62_62"></a><a href="#Footnote_62_62" class="fnanchor">[62]</a> -has pointed out, it is extremely improbable that the bergschrund of -glacial times under the conditions of a greater volume of snow could -have penetrated to bedrock at the base of the cirque where the present -change of slope takes place. In the second place, the assumption is -untenable that the bergschrund in all cases reaches to or anywhere near -the foot of the cirque wall. A third condition outside the hypothesis -and contradictory to it is the absence of a bergschrund in snowfields at -many valleys heads where cirques are well developed!</p> - -<p>Johnson himself called attention to the slender basis of observation -upon which his conclusions rest. In spite of his own caution with -respect to the use of his meager data, his hypothesis has been applied -in an entirely too confident manner to all kinds of cirques under all -kinds of conditions. Though Johnson descended an open bergschrund to a -rock floor upon which ice rested, his observations raise a number of -proper questions as to the application of these valuable data: How long -are bergschrunds open? How often are they open? Do they everywhere open -to the foot of the cirque wall? Are they present for even a part of the -year in all well-developed cirques? Let us suppose that it is possible -to find many cirques filled with snow, not ice, surrounded by truly -precipitous walls and with an absence of bergschrunds,<a name="page_296" id="page_296"></a> how shall we -explain the topographic depressions excavated underneath the snow? If -cirque formation can be shown to take place without concentrated frost -action at the foot of the bergschrund, then is the bergschrund not a -secondary rather than a primary factor? And must we not further conclude -that when present it but hastens an action which is common to all -snow-covered recesses?</p> - -<p>It is a pleasure to say that we may soon have a restatement of the -cirque problem from the father of the bergschrund idea. The argument in -this chapter was presented orally to him after he had remarked that he -was glad to know that some one was finding fault with his hypothesis. -“For,†he said, with admirable spirit, “I am about to make a most -violent attack upon the so-called Johnson hypothesis.†I wish to say -frankly that while he regards the following argument as a valid addition -to the problem, he does not think that it solves the problem. There are -many of us who will read his new explanation with the deepest interest.</p> - -<p><a name="fig_196" id="fig_196"></a></p> - -<div class="figleft" style="width: 110px;"> -<a href="images/ill_page_296_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_296_sml.jpg" width="51" height="59" alt="Fig. 196—Relation of cirque wall to trough’s end at the -head of a glaciated valley. The ratio of the inner to the outer radius -is 1:4." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 196—Relation of cirque wall to trough’s end at the -head of a glaciated valley. The ratio of the inner to the outer radius -is 1:4.</p> -</div> - -<p style="clear:both;"><a name="fig_197" id="fig_197"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_297_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_297_sml.jpg" width="211" height="108" alt="Fig. 197—Mode of cirque formation. Taking the facts of -snow depth represented in the curve, Fig. 195 , and transposing them over -a profile (the heavy line) which ranges from 0° declivity to 50°, we -find that the greatest excess of snow occurs roughly in the center. Here -ice will first form at the bottom of the snow in the advancing hemicycle -of glaciation, and here it will linger longest in the hemicycle of -retreat. Here also there will be the greatest mass of névé. All of these -factors are self-stimulating and will increase in time until the floor -of the cirque is flattened or depressed sufficiently to offset through -uphill ice-flow the augmented forces of erosion. The effects of -self-stimulation are shown by “snow increaseâ€; the ice shoe at the -bottom of the cirque is expressed by “ice factor.†The form accompanying -both these terms is merely suggestive. The top of “excess snow†has a -gradient characteristic of the surface of snow fields. A preglacial -gradient of 0° is not permissible, but I have introduced it to complete -the discussion in the text and to illustrate the flat floor of a cirque. -A bergschrund is not required for any stage of this process, though the -process is hastened wherever bergschrunds exist." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 197—Mode of cirque formation. Taking the facts of -snow depth represented in the curve, Fig. <a href="#fig_195">195</a> , and transposing them over -a profile (the heavy line) which ranges from 0° declivity to 50°, we -find that the greatest excess of snow occurs roughly in the center. Here -ice will first form at the bottom of the snow in the advancing hemicycle -of glaciation, and here it will linger longest in the hemicycle of -retreat. Here also there will be the greatest mass of névé. All of these -factors are self-stimulating and will increase in time until the floor -of the cirque is flattened or depressed sufficiently to offset through -uphill ice-flow the augmented forces of erosion. The effects of -self-stimulation are shown by “snow increaseâ€; the ice shoe at the -bottom of the cirque is expressed by “ice factor.†The form accompanying -both these terms is merely suggestive. The top of “excess snow†has a -gradient characteristic of the surface of snow fields. A preglacial -gradient of 0° is not permissible, but I have introduced it to complete -the discussion in the text and to illustrate the flat floor of a cirque. -A bergschrund is not required for any stage of this process, though the -process is hastened wherever bergschrunds exist.</p> -</div> - -<p>We shall begin with the familiar fact that many valleys, now without -perpetual snow, formerly contained glaciers from 500 to 1,000 feet thick -and that their snowfields were of wide extent and great depth. At the -head of a given valley where the snow is crowded into a small -cross-section it is compacted and suffers a reduction in its volume. At -first nine times the volume of ice, the gradually compacting névé -approaches the volume of ice as a limit. At the foot of the cirque wall -we may fairly assume in the absence of direct observations, a volume -reduction of one-half due to compacting. But this is offset in the case -of a well-developed cirque by volume increases due to the convergence of -the snow from the surrounding slopes, as shown in <a href="#fig_196">196</a> . Taking a -typical cirque from a point above Vilcabamba pueblo I find that the -radius of the trough’s end is to the radius of the upper wall of the -cirque as 1:4; and since the corresponding surfaces are<a name="page_297" id="page_297"></a> to one another -as the squares of their similar dimensions we have 1:4 or 1:16 as the -ratio of their snow areas. If no compacting took place, then to -accommodate all the snow in the glacial trough would require an increase -in thickness in the ratio of 1:4. If the snow were compacted to half its -original volume then the ratio would be 1:2. Now, since the volume ratio -of ice to snow is 1:9 and the thickness of the ice down valley is, say -400 feet, the equivalent of loose snow at the foot of the cirque must be -more than 1:4 over 1:9 or more than two and one-quarter times thicker, -or 400 feet thick; and would give a pressure of (900 ÷ 10) × 62.5 -pounds, or 5,625 pounds, or a little less than three tons per square -foot. Since a pressure of 2,500 pounds per square foot will convert snow -into ice at freezing temperature, it<a name="page_298" id="page_298"></a> is clear that ice and not snow was -the state at the bottom of the mass in glacial times. Further, between -the surface of the snow and the surface of the bottom layer of the ice -there must have been every gradation between loose snow and firm ice, -with the result that a thickness much less than 900 feet must be -assumed. Precisely what thickness would be found at the foot of the -cirque wall is unknown. But granting a thickness of 400 feet of ice an -additional 300 feet for névé and snow would raise the total to 700 feet.</p> - -<p>The application of the facts in the above paragraph is clearly seen when -we refer to <a href="#fig_197">197</a> . The curve of snow motion of <a href="#fig_195">195</a> is applied to -an unglaciated mountain valley. Taking a normal snow surface and filling -the valley head it is seen that the excess of snow depth over the amount -required to give motion is a measure at various points in the valley -head and at different gradients of the erosive force of the snow. It is -strikingly concentrated on the 15°-20° gradient which is precisely where -the so-called process of basal sapping is most marked. If long continued -the process will lead to the developing of a typical cirque for it is a -process that is self-stimulating. The more the valley is changed in form -the more it tends to change still further in form because of deepening -snowfields until cliffed pinnacles and matterhorns result.</p> - -<p>By further reference to the figure it is clear that a schrund 350 feet -deep could not exist on a cirque wall with a declivity of even 20° -without being closed by flow, unless we grant <i>more rapid flow</i> below -the crevasse. In the case of a glacier flowing over a nearly flat bed -away from the cirque it is difficult to conceive of a rate of flow -greater than that of snow and névé on the steep lower portion of the -cirque wall, when movement on that gradient <i>begins</i> with snow but 20 -feet thick.</p> - -<p>In contrast to this is the view that the schrund line should lie well up -the cirque wall where the snow is comparatively thin and where there is -an approach to the lower limits of movement. The schrund would appear to -open where the bottom material changes its form, i.e., where it first -has its motion accelerated by<a name="page_299" id="page_299"></a> transformation into névé. In this view -the schrund opens not at the foot of the cirque wall but well above it -as in <a href="#fig_198">198</a> , in which <i>C</i> represents snow from top to bottom; <i>B</i>, -névé; and <i>A</i>, ice. The required conditions are then (1) that the -steepening of the cirque wall from <i>x</i> to <i>y</i> should be effected by -sapping originated at <i>y</i> through the agencies outlined by Johnson; (2) -that the steepening from <i>x</i> to <i>y</i> should be effected by sapping -originated at <i>x</i> through the change of the agent from névé to ice with -a sudden change of function; (3) and that the essential unity of the -wall <i>x-y-z</i> be maintained through the erosive power of the névé, which -would tend to offset the formation of a shelf along a horizontal plane -passed through <i>y</i>. The last-named process not only appears entirely -reasonable from the conditions of gradient and depth outlined on pp. 296 -to 298, but also meets the actual field conditions in all the cases -examined in the Peruvian Andes. This brings up the second and third of -our main considerations, that the bergschrund does not always or even in -many cases reach the foot of the cirque wall, and that cirques exist in -many cases where bergschrunds are totally absent.</p> - -<p>It is a striking fact that frost action at the bottom of the bergschrund -has been assumed to be the only effective sapping force, in spite of the -common observation that bergschrunds lie in general well toward the -upper limits of snowfields—so far, in fact, that their bottoms in -general occur several hundred feet above the cirque floors. Is the -cirque under these circumstances a result of the schrund or is the -schrund a result of the cirque? <i>In what class of cirques do schrunds -develop?</i> If cirque development in its early stages is not marked by the -development of bergschrunds, then are bergschrunds an <i>essential</i> -feature of cirques in their later stages, however much the sapping -process may be hastened by schrund formation?</p> - -<p>Our questions are answered at once by the indisputable facts that many -schrunds occur well toward the upper limit of snow, and that many -cirques exist whose snowfields are not at all broken by schrunds. It was -with great surprise that I first noted the bergschrunds of the Central -Andes, especially after becoming<a name="page_300" id="page_300"></a> familiar with Johnson’s apparently -complete proof of their genetic relation to the cirques. But it was less -surprising to discover the position of the few observed—high up on the -cirque walls and always near the upper limit of the snowfields.</p> - -<p>A third fact from regions once glaciated but now snow-free also combined -with the two preceding facts in weakening the wholesale application of -Johnson’s hypothesis. In many headwater basins the cirque whose wall at -a distance seemed a unit was really broken into two unequal portions; a -lower, much grooved and rounded portion and an upper unglaciated, -steep-walled portion. This condition was most puzzling in view of the -accepted explanation of cirque formation, and it was not until the two -first-named facts and the applications of the curves of snow motion were -noted that the meaning of the break on the cirque became clear. -Referring to <a href="#fig_198">198</a> we see at once that the break occurs at <i>y</i> and -means that under favorable topographic and geologic conditions sapping -at <i>y</i> takes place faster than at <i>x</i> and that the retreat of <i>y-z</i> is -faster than <i>x-y</i>. It will be clear that when these conditions are -reversed or sapping at <i>x</i> and at <i>y</i> are equal a single wall will -result. On reference to the literature I find that Gilbert recently -noted this feature and called it the <i>schrundline</i>.<a name="FNanchor_63_63" id="FNanchor_63_63"></a><a href="#Footnote_63_63" class="fnanchor">[63]</a> He believes that -it marks the base of the bergschrund <i>at a late stage in the excavation -of the cirque basin</i>. He notes further that the lower less-steep slope -is glacially scoured and that it forms “a sort of shoulder or terrace.â€</p> - -<p><a name="fig_198" id="fig_198"></a></p> - -<div class="figleft" style="width: 125px;"> -<a href="images/ill_page_300_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_300_sml.jpg" width="105" height="56" alt="Fig. 198—The development of cirques. See text, p. 209, -and Fig. 199." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 198—The development of cirques. See text, p. 209, -and <a href="#fig_199">199</a> .</p> -</div> - -<p>If all the structural and topographic conditions were known in a great -variety of gathering basins we should undoubtedly find in them, and not -in special forms of ice erosion, an explanation of the various forms -assumed by cirques. The limitations inherent in a high-altitude field -and a limited snow cover prevented<a name="page_301" id="page_301"></a> me from solving the problem, but it -offered sufficient evidence at least to indicate the probable lines of -approach to a solution. For example it is noteworthy that in <i>all</i> the -cases examined the schrundline was better developed the further glacial -erosion had advanced. So constantly did this generalization check up, -that if at a distance a short valley was observed to end in a cirque, I -knew at once and long before I came to the valley head that a shoulder -below the schrundline did not exist. At the time this observation was -made its significance was a mystery, but it represents a condition so -constant that it forms one of the striking features of the glacial forms -in the headwater region.</p> - -<p><a name="fig_199" id="fig_199"></a></p> - -<div class="figright" style="width: 124px;"> -<a href="images/ill_page_301_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_301_sml.jpg" width="104" height="48" alt="Fig. 199—Further stages in the development of cirques. -See p. 299 and Fig. 198." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 199—Further stages in the development of cirques. -See <a href="#page_299">p. 299</a> and <a href="#fig_198">198</a> .</p> -</div> - -<p>The meaning of this feature is represented in <a href="#fig_199">199</a> , in which three -successive stages in cirque development are shown. In <i>A</i>, as displayed -in small valleys or mountainside alcoves which were but temporarily -occupied by snow and ice, or as in all higher valleys during the earlier -stages of the advancing hemicycle of glaciation, snow collects, a short -glacier forms, and a bergschrund develops. As a result of the -concentrated frost action at the base of the bergschrund a rapid -deepening and steepening takes place at <i>a</i>. As long as the depth of -snow (or snow and névé) is slight the bergschrund may remain open. But -its existence at this particular point is endangered as the cirque -grows, since the increasing steepness of the slope results in more rapid -snow movement. Greater depth of snow goes hand in hand with increasing -steepness and thus favors the formation of névé and even ice at the -bottom of the moving mass and a constantly accelerated rate of motion. -At the same time the bergschrund should appear higher up for an -independent reason, namely, that it tends to form between a mass of -slight movement and one of greater movement, which change of function, -as already pointed out, would appear to be controlled by change from -snow to névé or ice on the part of the bottom material.<a name="page_302" id="page_302"></a></p> - -<p>The first stages in the upward migration of the bergschrund will not -effect a marked change from the original profile, since the converging -slopes, the great thickness of névé and ice at this point, and the steep -gradient all favor powerful erosion. When, however, stage <i>C</i> is -reached, and the bergschrund has retreated to <i>c″</i>, a broader terrace -results below the schrundline, the gradient is decreased, the ice and -névé (since they represent a constant discharge) are spread over a -greater area, hence are thinner, and we have the cirque taking on a -compound character with a lower, less steep and an upper, precipitous -section.</p> - -<p>It is clear that a closely jointed and fragile rock might be quarried by -moving ice at <i>c′-c″</i> and the cirque wall extended unbroken to <i>x</i>; it -is equally clear that a homogeneous, unjointed granite would offer no -opportunities for glacial plucking and would powerfully resist the much -slower process of abrasion. Thus Gilbert<a name="FNanchor_64_64" id="FNanchor_64_64"></a><a href="#Footnote_64_64" class="fnanchor">[64]</a> observed the schrundline in -the granites of the Sierra Nevada, which are “in large part -structureless†and my own observations show the schrundline well -developed in the open-jointed granites of the Cordillera Vilcapampa and -wholly absent in the volcanoes of the Maritime Cordillera, where ashes -and cinders, the late products of volcanic action, form the easily -eroded walls of the steep cones. Somewhere between these extremes—lack -of a variety of observations prevents our saying where—the resistance -and the internal structure of the rock will just permit a cirque wall to -extend from <i>x</i> to <i>c′ ″</i> of <a href="#fig_199">199</a> .</p> - -<p>A common feature of cirques that finds an explanation in the proposed -hypothesis is the notch that commonly occurs at some point where a -convergence of slopes above the main cirque wall concentrates snow -discharge. It is proposed to call this type the notched cirque. It is -highly significant that these notches are commonly marked by even -steeper descents at the point of discharge into the main cirque than the -remaining portion of the cirque wall, even when the discharge was from a -very small basin and in the form of snow or at the most névé. The excess -of discharge at a point on the basin rim ought to produce the form<a name="page_303" id="page_303"></a> we -find there under the conditions of snow motion outlined in earlier -paragraphs. It is also noteworthy that it is at such a point of -concentrated discharge that crevasses no sooner open than they are -closed by the advancing snow masses. To my mind the whole action is -eminently representative of the action taking place elsewhere along the -cirque wall on a smaller scale.</p> - -<p>What seems a good test of the explanation of cirques here proposed was -made in those localities in the Maritime Cordillera, where large -snowbanks but not glaciers affect the form of the catchment basins. A -typical case is shown in <a href="#fig_201">201</a> . As in many other cases we have here a -great lava plateau broken frequently by volcanic cones of variable -composition. Some are of lava, others consist of ashes, still others of -tuff and lava and ashes. At lower elevations on the east, as at 16,000 -feet between Antabamba and Huancarama, evidences of long and powerful -glaciers are both numerous and convincing. But as we rise still higher -the glaciated topography is buried progressively deeper under the -varying products of volcanic action, until finally at the summit of the -lava fields all evidences of glaciation disappear in the greater part of -the country between Huancarama and the main divide. Nevertheless, the -summit forms are in many cases as significantly altered as if they had -been molded by ice. Precipitous cirque walls surround a snow-filled -amphitheater, and the process of deepening goes forward under one’s -eyes. No moraines block the basin outlets, no U-shaped valleys lead -forward from them. We have here to do with post-glacial action pure and -simple, the volcanoes having been formed since the close of the -Pleistocene.</p> - -<p>Likewise in the pass on the main divide, the perpetual snow has begun -the recessing of the very recent volcanoes bordering the pass. The -products of snow action, muds and sands up to very coarse gravel, -glaciated in texture with an intermingling of blocks up to six inches in -diameter in the steeper places, are collected into considerable masses -at the snowline, where they form broad sheets of waste so boggy as to be -impassable except by carefully selected routes. No ice action whatever -is visible below<a name="page_304" id="page_304"></a> the snowline and the snow itself, though wet and -compact, is not underlain by ice. Yet the process of hollowing goes -forward visibly and in time will produce serrate forms. In neither case -is there the faintest sign of a bergschrund; the gradients seem so well -adjusted to the thickness and rate of movement of the snow from point to -point that the marginal crack found in many snowfields is absent.</p> - -<p>The absence of bergschrunds is also noteworthy in many localities where -formerly glaciation took place. This is notoriously the case in the -summit zone of the Cordillera Vilcapampa, where the accumulating snows -of the steep cirque walls tumble down hundreds of feet to gather into -prodigious snowbanks or to form névé fields or glaciers. From the -converging walls the snowfalls keep up an intermittent bombardment of -the lower central snow masses. It is safe to say that if by magic a -bergschrund could be opened on the instant, it would be closed almost -immediately by the impetus supplied by the falling snow masses. The -explanation appears to be that the thicker snow and névé concentrated at -the bottom of the cirque results in a corresponding concentration of -action and effect; and cirque development goes on without reference to a -bergschrund. The chief attraction of the bergschrund hypothesis lies in -the concentration of action at the foot of the cirque wall. But in the -thickening of the snow far beyond the minimum thickness required for -motion at the base of the cirque wall and its change of function with -transformation into névé, we need invoke no other agent. If a -bergschrund forms, its action may take place at the foot of the cirque -wall or high up on the wall, and yet <i>sapping at the foot of the wall</i> -continue.</p> - -<div class="figcenter"> -<a href="images/ill_page_304a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_304a_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_304a_sml.jpg" width="381" height="425" alt="THE YALE PERUVIAN EXPEDITION OF 1911 -HIRAM BINGHAM DIRECTOR -LAMBRAMA QUADRANGLE" /> -</div> - -<p>From which we conclude (1) that where frost action occurs at the bottom -of a bergschrund opening to the foot of the cirque wall it aids in the -retreat of the wall; (2) that a sapping action takes place at this point -whether or not a bergschrund exists and that bergschrund action is not a -<i>necessary</i> part of cirque formation; (3) that when a more or less -persistent bergschrund opens on the cirque wall above its foot it tends -to develop a schrundline with a marked terrace below it; (4) that -schrundlines are best developed<a name="page_305" id="page_305"></a> in the mature stages of topographic -development in the glacial cycle; (5) that the varying rates of snow, -névé, and ice motion at a valley head are the <i>persistent</i> features to -which we must look for topographic variations; (6) that the hypothesis -here proposed is applicable to all cases whether they involve the -presence of snow or névé or ice or any combination of these, and whether -bergschrunds are present or not; and (7) at the same time affords a -reasonable explanation for such variations in forms as the compound -cirque with its schrundline and terrace, the unbroken cirque wall, the -notched cirque, and the recessed, snow-covered mountain slopes -unaffected by ice.</p> - -<h4>ASYMMETRICAL CREST LINES AND ABNORMAL VALLEY PROFILES IN THE CENTRAL ANDES</h4> - -<p>To prove that under similar conditions glacial erosion may be greater -than subaërial denudation quantitative terms must be sought. Only these -will carry conviction to the minds of many opponents of the theory that -ice is a vigorous agent of erosion. Gilbert first showed in the Sierra -Nevada that headwater glaciers eroded more rapidly than nonglacial -agents under comparable topographic and structural conditions.<a name="FNanchor_65_65" id="FNanchor_65_65"></a><a href="#Footnote_65_65" class="fnanchor">[65]</a> Oddly -enough none of the supporters of opposing theories have replied to his -arguments; instead they have sought evidence from other regions to show -that ice cannot erode rock to an important degree. In this chapter -evidence from the Central Andes, obtained in 1907 and 1911, will be -given to show the correctness of Gilbert’s proposition.</p> - -<p>The data will be more easily understood if Gilbert’s argument is first -outlined. On the lower slopes of the glaciated Sierra Nevada asymmetry -of form resulted from the presence of ice on one side of each ridge and -its absence on the other (<a href="#fig_200">Fig. 200</a>). The glaciers of these lower ridges -were the feeblest in the entire region and were formed on slopes of -small extent; they were also short-lived, since they could have existed -only when glacial conditions had reached a maximum. Let the broken line -in the upper<a name="page_306" id="page_306"></a> part of the figure represent the preglacial surface and -the solid line beneath it the present surface. It will not matter what -value we give the space between the two lines on the left to express -nonglacial erosion, since had there been no glaciers it would be the -same on both sides of the ridge. The feeble glacier occupying the -right-hand slope was able in a very brief period to erode a depression -far deeper than the normal agents of denudation were able to erode in a -much longer period, i.e., during all of interglacial and postglacial -time. Gilbert concludes: “The visible ice-made hollows, therefore, -represent the local excess of glacial over nonglacial conditions.â€</p> - -<p><a name="fig_200" id="fig_200"></a></p> - -<p><a name="fig_201" id="fig_201"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_306_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_306_sml.jpg" width="209" height="21" alt="Fig. 200—Diagrammatic cross-section of a ridge glaciated -on one side only; with hypothetical profile (broken line) of preglacial -surface." /></a> -<br /> - -<table border="0" cellpadding="5" cellspacing="0" summary=""> -<tr valign="top"><td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 200—Diagrammatic cross-section of a ridge glaciated -on one side only; with hypothetical profile (broken line) of preglacial -surface.</p></td> - -<td class="swidth"><p class="caption"><span class="smcap">Fig</span>. 201—Postglacial volcano recessed on shady southern -side by the process of nivation. Absolute elevation 18,000 feet (5,490 -m.), latitude 14° S., Maritime Cordillera, Peru.</p></td></tr></table> -</div> - -<p>In the Central Andes are many volcanic peaks and ridges formed since the -last glacial epoch and upon them a remarkable asymmetry has been -developed. Looking southward one may see a smoothly curved, snow-free, -northward-facing slope rising to a crest line which appears as regular -as the slope leading to it. Looking northward one may see by contrast -(<a href="#fig_194">Fig. 194</a>) sharp ridges, whose lower crests are serrate, separated by -deeply recessed, snow-filled mountain hollows. Below this highly -dissected zone the slopes are smooth. The smooth slope represents the -work of water; the irregular slopes are the work of snow and ice. The -relation of the north and south slopes is diagrammatically shown in Fig. -201.</p> - -<p>To demonstrate the erosive effects of snow and ice it must be shown: (1) -that the initial slopes of the volcanoes are of postglacial age; (2) -that the asymmetry is not structural; (3) that the snow-free slopes have -not had special protection, as through a more abundant plant cover, more -favorable soil texture, or otherwise.<a name="page_307" id="page_307"></a></p> - -<p>Proof of the postglacial origin of the volcanoes studied in this -connection is afforded: (1) by the relation of the flows and the ash and -cinder beds about the bases of the cones to the glacial topography; (2) -by the complete absence of glacial phenomena below the present snowline. -Ascending a marginal valley (<a href="#fig_202">Fig. 202</a>), one comes to its head, where two -tributaries, with hanging relations to the main valley, come down from a -maze of lesser valleys and irregular slopes. Glacial features of a -familiar sort are everywhere in evidence until we come to the valley -heads. Cirques, reversed grades, lakes, and striæ are on every hand. But -at altitudes above 17,200 feet, recent volcanic deposits have over large -areas entirely obscured the older glacial topography. The glacier which -occupied the valley of <a href="#fig_202">202</a> was more than one-quarter of a mile -wide, the visible portion of its valley is now over six miles long, but -the extreme head of its left-hand tributary is so concealed by volcanic -material that the original length of the glacier cannot be determined. -It was at least ten miles long. From this point southward to the border -of the Maritime Cordillera no evidence of past glaciation was observed, -save at Solimana and Coropuna, where slight changes in the positions of -the glaciers have resulted in the development of terminal moraines a -little below the present limits of the ice.</p> - -<p>From the wide distribution of glacial features along the northeastern -border of the Maritime Cordillera and the general absence of such -features in the higher country farther south, it is concluded that the -last stages of volcanic activity were completed in postglacial time. It -is equally certain, however, that the earlier and greater part of the -volcanic material was ejected before glaciation set in, as shown by the -great depth of the canyons (over 5,000 feet) cut into the lava flows, as -contrasted with the relatively slight filling of coarse material which -was accumulated on their floors in the glacial period and is now in -process of dissection. Physiographic studies throughout the Central -Andes demonstrate both the general distribution of this fill and its -glacial origin.</p> - -<p>So recent are some of the smaller peaks set upon the lava<a name="page_308" id="page_308"></a> plateau that -forms the greater part of the Maritime Cordillera, that the snows massed -on their shadier slopes have not yet effected any important topographic -changes. The symmetrical peaks of this class are in a few cases so very -recent that they are entirely uneroded. Lava flows and beds of tuff -appear to have originated but yesterday, and shallow lava-dammed lakes -retain their original shore relations. In a few places an older -topography, glacially modified, may still be seen showing through a -veneer of recent ash and cinder deposits, clear evidence that the -loftier parts of the lava plateau were glaciated before the last -volcanic eruption.</p> - -<p>The asymmetry of the peaks and ridges in the Maritime Cordillera cannot -be ascribed to the manner of eruption, since the contrast in declivity -and form is persistently between northern and southern slopes. Strong -and persistent winds from a given direction undoubtedly influence the -form of volcanoes to at least a perceptible degree. In the case in hand -the ejectamenta are ashes, cinders, and the like, which are blown into -the air and have at least a small component of motion down the wind -during both their ascent and descent. The <i>prevailing</i> winds of the high -plateaus are, however, easterly and the strongest winds are from the -west and blow daily, generally in the late afternoon. Both wind -directions are at right angles to the line of asymmetry, and we must, -therefore, rule out the winds as a factor in effecting the slope -contrasts which these mountains display.</p> - -<p>It remains to be seen what influence a covering of vegetation on the -northern slopes might have in protecting them from erosion. The northern -slopes in this latitude (14° S.) receive a much greater quantity of heat -than the southern slopes. Above 18,000 feet (5,490 m.) snow occurs on -the shady southern slopes, but is at least a thousand feet higher on the -northern slopes. It is therefore absent from the northern side of all -but the highest peaks. Thus vegetation on the northern slopes is not -limited by snow. Bunch grass—the characteristic <i>ichu</i> of the mountain -shepherds—scattered spears of smaller grasses, large ground mosses -called <i>yareta</i>, and lichens extend to the snowline. This<a name="page_309" id="page_309"></a> vegetation, -however, is so scattered and thin above 17,500 feet (5,330 m.) that it -exercises no retarding influence on the run-off. Far more important is -the porous nature of the volcanic material, which allows the rainfall to -be absorbed rapidly and to appear in springs on the lower slopes, where -sheets of lava direct it to the surface.</p> - -<p>The asymmetry of the north and south slopes is not, then, the result of -preglacial erosion, of structural conditions, or of special protection -of the northern slopes from erosion. It must be concluded, therefore, -that it is due to the only remaining factor—snow distribution. The -southern slopes are snow-clad, the northern are snow-free—in harmony -with the line of asymmetry. The distribution of the snow is due to the -contrasts between shade and sun temperatures, which find their best -expression in high altitudes and on single peaks of small extent. -Frankland’s observations with a black-bulb thermometer <i>in vacuo</i> show -an increase in shade and sun temperatures contrasts of over 40° between -sea level and an elevation of 10,000 feet. Violle’s experiments show an -increase of 26 per cent in the intensity of solar radiation between 200 -feet and 16,000 feet elevation. Many other observations up to 16,000 -feet show a rapid increase in the difference between sun and shade -temperatures with increasing elevation. In the region herein described -where the snowline is between 18,000 and 19,000 feet (5,490 to 5,790 m.) -these contrasts are still further heightened, especially since the -semi-arid climate and the consequent long duration of sunshine and low -relative humidity afford the fullest play to the contrasting forces. The -coefficient of absorption of radiant energy by water vapor is 1,900 -times that of air, hence the lower the humidity the more the radiant -energy expended upon the exposed surface and the greater the sun and -shade contrasts. The effect of these temperature contrasts is seen in a -canting of the snowline on individual volcanoes amounting to 1,500 feet -in extreme instances. The average may be placed at 1,000 feet.</p> - -<p>The minimum conditions of snow motion and the bearing of the conclusions -upon the formation of cirques have been described<a name="page_310" id="page_310"></a> in the chapters -immediately preceding. It is concluded that snow moves upon 20° slopes -if the snow is at least forty feet deep, and that through its motion -under more favorable conditions of greater depth and gradient and the -indirect effects of border melting there is developed a hollow occupied -by the snow. Actual ice is not considered to be a necessary condition of -either movement or erosion. We may at once accept the conclusion that -the invariable association of the cirques and steepened profiles with -snowfields proves that snow is the predominant modifying agent.</p> - -<p>An argument for glacial erosion based on profiles and steep cirque walls -in a volcanic region has peculiar appropriateness in view of the -well-known symmetrical form of the typical volcano. Instead of varied -forms in a region of complex structure long eroded before the appearance -of the ice, we have here simple forms which immediately after their -development were occupied by snow. <i>Ever since their completion these -cones have been eroded by snow on one side and by water on the other.</i> -If snow cannot move and if it protects the surface it covers, then this -surface should be uneroded. All such surfaces should stand higher than -the slopes on the opposite aspect eroded by water. But these assumptions -are contrary to fact. The slopes underneath the snow are deeply -recessed; so deeply eroded indeed, that they are bordered by steep -cliffs or cirque walls. The products of erosion also are to some extent -displayed about the border of the snow cover. In strong contrast the -snow-free slopes are so slightly modified that little of their original -symmetry is lost—only a few low hills and shallow valleys have been -formed.</p> - -<p>The measure of the excess of snow erosion over water erosion is -therefore the difference between a northern or water-formed and a -southern or snow-formed profile, <a href="#fig_200">200</a> . This difference is also shown -in <a href="#fig_201">201</a> and from it and the restored initial profiles we conclude -that the rate of water erosion is to that of nivation as 1:3. This ratio -has been derived from numerous observations on cones so recently formed -that the interfluves without question are still intact.</p> - -<p><a name="fig_202" id="fig_202"></a></p> - -<div class="figright" style="width: 40%;"> -<a href="images/ill_page_311_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_311_sml.jpg" width="117" height="51" alt="Fig. 202—Graphic representation of amount of glacial -erosion during the glacial period. In the background are mature slopes -surmounted by recessed asymmetrical peaks. The river entrenched itself -below the mature slopes before it began to aggrade, and, when -aggradation set in, had cut its valley floor to a′-b′-c. By aggradation -the valley floor was raised to a-b while ice occupied the valley head. -By degradation the river has again barely lowered its channel to a′-b′, -the ice has disappeared, and the depression of the profile represents -the amount of glacial erosion. - -a′-b′-c = preglacial profile. -a-b-d-c = present profile. -b′-d-c-b = total ice erosion in the glacial period. -a-b = surface of an alluvial valley fill due to excessive erosion at valley head. -b-b′ = terminal moraine. -d-c = cirque wall. -e, e′ e″ = asymmetrical summits." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 202—Graphic representation of amount of glacial -erosion during the glacial period. In the background are mature slopes -surmounted by recessed asymmetrical peaks. The river entrenched itself -below the mature slopes before it began to aggrade, and, when -aggradation set in, had cut its valley floor to a′-b′-c. By aggradation -the valley floor was raised to a-b while ice occupied the valley head. -By degradation the river has again barely lowered its channel to a′-b′, -the ice has disappeared, and the depression of the profile represents -the amount of glacial erosion.</p> -<p class="spec"> -a′-b′-c = preglacial profile.<br /> -a-b-d-c = present profile.<br /> -b′-d-c-b = total ice erosion in the glacial period.<br /> -a-b = surface of an alluvial valley fill due to excessive erosion at valley head.<br /> -b-b′ = terminal moraine.<br /> -d-c = cirque wall.<br /> -e, e′ e″ = asymmetrical summits.</p> -</div> - -<p>Thus far only those volcanoes have been considered which<a name="page_311" id="page_311"></a> have been -modified by nivation. There are, however, many volcanoes which have been -eroded by ice as well as by snow and water. It will be seen at once that -where a great area of snow is tributary to a single valley, the snow -becomes compacted into névé and ice, and that it then erodes at a much -faster rate. Also a new force—plucking—is called into action when ice -is present, and this greatly accelerates the rate of erosion. While it -lies outside the limits of my subject to determine quantitatively the -ratio between water and ice action, it is worth pointing out that by -this method a ratio much in excess of 1:3 is determined, which even in -this rough form is of considerable interest in view of the arguments -based on the protecting influence of both ice and snow. I have, indeed, -avoided the question of ice erosion up to this point and limited myself -to those volcanoes which have been modified by nivation only, since the -result is more striking in view of the all but general absence of data -relating to this form of erosion.</p> - -<p style="clear:both;"><a name="fig_203" id="fig_203"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_312_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /> -<br /><img src="images/ill_page_312_sml.jpg" width="334" height="68" alt="Fig. 203—A composite sketch to represent general -conditions in the Peruvian Andes. In order to have the actual facts -represented the profiles of this figure were taken from the accompanying -topographic sheets. The main depression on the right and the -corresponding depression of the tributary profiles bear out most -strikingly the conclusions concerning the erosive power of the ice. At -A and B the spurs have been cut off to exhibit the profiles of -tributary valleys. At 2 and 3 were tributary glaciers of such size -that they entered the main valley at grade. Lesser tributaries had -floors elevated above those they joined and now have a hanging -character, as just above 2. D is a matterhorn; C is deeply -recessed by cirques; E represents a peak just below the limit of -glaciation. At F are the undissected post-mature slopes of an earlier -cycle of erosion. G lies on the steep lower slopes formed during the -canyon cycle of erosion. The down-cutting of the stream in the canyon -cycle was generally checked by glaciation and was superseded by -aggradation." /></a> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 203—A composite sketch to represent general -conditions in the Peruvian Andes. In order to have the actual facts -represented the profiles of this figure were taken from the accompanying -topographic sheets. The main depression on the right and the -corresponding depression of the tributary profiles bear out most -strikingly the conclusions concerning the erosive power of the ice. At -A and B the spurs have been cut off to exhibit the profiles of -tributary valleys. At 2 and 3 were tributary glaciers of such size -that they entered the main valley at grade. Lesser tributaries had -floors elevated above those they joined and now have a hanging -character, as just above 2. D is a matterhorn; C is deeply -recessed by cirques; E represents a peak just below the limit of -glaciation. At F are the undissected post-mature slopes of an earlier -cycle of erosion. G lies on the steep lower slopes formed during the -canyon cycle of erosion. The down-cutting of the stream in the canyon -cycle was generally checked by glaciation and was superseded by -aggradation.</p> -</div> - -<p>If we now turn to the valley profiles of the glaciated portions of the -Peruvian Andes, we shall see the excess of ice over water erosion -expressed in a manner equally convincing. To a thoughtful person it is -one of the most remarkable features of any glaciated region that the -flattest profiles, the marshiest valley flats, and the most strongly -meandering stretches of the streams should occur near the heads of the -valleys. The mountain shepherds<a name="page_312" id="page_312"></a> recognize this condition and drive -their flocks up from the warmer valley into the mountain recesses, -confident that both distance and elevation will be offset by the -extensive pastures of the finest <i>ichu</i> grass. Indeed, to be near the -grazing grounds of sheep and llamas which are their principal means of -subsistence, the Indians have built their huts at the extraordinarily -lofty elevations of 16,000 to 17,000 feet.</p> - -<p>An examination of a large number of these valleys and the plotting of -their gradients discloses the striking fact that the heads of the -valleys were deeply sunk into the mountains. It is thus possible by -restoring the preglacial profiles to measure with considerable certainty -the excess of ice over water erosion.</p> - -<p>The results are graphically expressed in <a href="#fig_202">202</a> . It will be seen that -until glacial conditions intervened the stream was flowing on a rock -floor. During the whole of glacial time it<a name="page_313" id="page_313"></a> was aggrading its rock floor -below <i>b′</i> and forming a deep valley fill. A return to warmer and drier -conditions led to the dissection of the fill and this is now in -progress. The stream has not yet reached its preglacial profile, but it -has almost reached it. We may, therefore, say that the preglacial valley -profile below <i>b′</i> fixes the position of the present profile just as -surely as if the stream had been magically halted in its work at the -beginning of the period of glaciation. There, <i>b′-d-c-b</i> represents the -amount of ice erosion. To be sure the line <i>b-c</i> is inference, but it is -reasonable inference and, whatever position is assigned to it, it cannot -be coincident with <i>b′-d</i>, nor can it be anywhere near it. The break in -the valley profile at <i>b′</i> is always marked by a terminal moraine, -regardless of the character of the rock. This is not an accidental but a -causal association. It proves the power of the ice to erode. In glacial -times it eroded the quantity <i>b-c-d-b′</i>. This is not an excess of ice -over water erosion, but an absolute measure of ice erosion, since -<i>a′-b′</i> has remained intact. The only possible error arises from the -position assigned <i>b-c</i>, and even if we lower it to <i>b-c′</i> (for which we -have no warrant but extreme conservatism) we shall still have left -<i>b′-c′-d-b</i> as a striking value for rock erosion (plucking and abrasion) -by a valley glacier.</p> - -<p>A larger diagram, <a href="#fig_203">203</a> , represents in fuller detail the topographic -history of the Andes of southern Peru and the relative importance of -glaciation. The broad spurs with grass-covered tops that end in steep -scarps are in wonderful contrast to the serrate profiles and truncated -spurs that lie within the zone of past glaciation. In the one case we -have minute irregularities on a canyon wall of great dimensions; in the -other, more even walls that define a glacial trough with a flat floor. -Before glaciation on a larger scale had set in the right-hand section of -the diagram had a greater relief. It was a residual portion of the -mountain and therefore had greater height also. Glaciers formed upon it -in the Ice Age and glaciation intensified the contrast between it and -the left-hand section; not so much by intensifying the relief as by -diversifying the topographic forms.</p> - -<p><a name="fig_204" id="fig_204"></a></p> - -<div class="figcenter"> -<a href="images/ill_page_314a_lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="18" -height="14" /></a> -<a href="images/ill_page_314a_ex-lg.jpg"> -<img class="enlargeimage" -src="images/enlarge-image.jpg" -alt="enlarge-image" -title="enlarge-image" -width="28" -height="19" /></a> -<br /><img src="images/ill_page_314a_sml.jpg" width="104" height="389" alt="Fig. 204—Topographic map of the Andes between Abancay -and the Pacific Coast at Camaná. Compiled from the seven accompanying -topographic sheets (see Contents, p. xi). Scale 1:1,000,000. Contour -interval 1,000 feet. Longitude west of Greenwich. The Central Ranges of -the Maritime Cordillera are not confined to the area covered by these -names. In the one case the term includes all the ranges between Lambrama -and Huichihua; in the other case, the peaks and ranges from 14° 30′ S. -to Mt. Coropuna." /> -<br /> -<p class="caption"><span class="smcap">Fig</span>. 204—Topographic map of the Andes between Abancay -and the Pacific Coast at Camaná. Compiled from the seven accompanying -topographic sheets (see Contents, p. xi). Scale 1:1,000,000. Contour -interval 1,000 feet. Longitude west of Greenwich. The Central Ranges of -the Maritime Cordillera are not confined to the area covered by these -names. In the one case the term includes all the ranges between Lambrama -and Huichihua; in the other case, the peaks and ranges from 14° 30′ S. -to Mt. Coropuna.</p> -</div> - -<p><a name="page_315" id="page_315"></a></p> - -<h3><a name="APPENDIX_A" id="APPENDIX_A"></a>APPENDIX A<br /><br /> -SURVEY METHODS EMPLOYED IN THE CONSTRUCTION OF THE SEVEN ACCOMPANYING TOPOGRAPHIC SHEETS</h3> - -<p class="c"><span class="smcap">By Kai Hendriksen, Topographer</span></p> - -<p>The main part of the topographical outfit consisted of (1) a 4-inch -theodolite, Buff and Buff, the upper part detachable, (2) an 18 x 24 -inch plane-table with Johnson tripod and micro-meteralidade. These -instruments were courteously loaned the expedition by the U. S. Coast -and Geodetic Survey and the U. S. Geological Survey respectively.</p> - -<p>The method of survey planned was a combination of graphic triangulation -and traverse with the micro-meteralidade. All directions were plotted on -the plane-table which was oriented by backsight; distances were -determined by the micro-meteralidade or triangulation, or both combined; -and elevations were obtained by vertical angles. Finally, astronomical -observations, usually to the sun, were taken at intervals of about 60 -miles for latitude and azimuth to check the triangulation. No -observations were made for differences in longitude because this would -probably not have given any reliable result, considering the time and -instruments at our disposal. Because the survey was to follow very -closely the seventy-third meridian west of Greenwich, directions and -distances, checked by latitude and azimuth observations, undoubtedly -afforded far better means of determining the longitude than time -observations. In other words, the time observations made in connection -with azimuth observations were not used for computing longitudinal -differences. Absolute longitude was taken from existing observations of -principal places.</p> - -<p>Principal topographical points were located by from two to four -intersections from the triangulation and plane-table stations; and -elevations were determined by vertical angle measurements. Whenever -practicable, the contours were sketched in the field; the details of the -topography otherwise depend upon a great number of photographs taken by -Professor Bowman from critical stations or other points which it was -possible to locate on the maps.</p> - -<h4><span class="smcap">Cross-Section Map from Abancay to Camaná at the Pacific Ocean</span></h4> - -<p class="nind">Seven sheets. Scale, 1:125,000; contour interval, 200 feet. Datum is -mean sea level. Astronomical control: 5 latitude and 5 azimuth -observations as indicated on the accompanying topographic sheets.<a name="page_316" id="page_316"></a></p> - -<p>On September 10th, returning from a reconnaissance survey of the -Pampaconas River, I joined Professor Bowman’s party, Dr. Erving acting -as my assistant. We crossed the Cordillera Vilcapampa and the Canyon of -the Apurimac and after a week’s rest at Abancay started the topographic -work near Hacienda San Gabriel south of Abancay. Working up the deep -valley of Lambrama, observations for latitude and azimuth were made -midway between Hacienda Matara and Caypi.</p> - -<p>On October 4th we made our camp in newly fallen snow surrounded by -beautiful glacial scenery. The next day on the high plateau, we passed -sharp-crested glaciated peaks; a heavy thunder and hail storm broke out -while I occupied the station at the pass, the storm continuing all the -afternoon—a frequent occurrence. The camp was made 6 miles farther on, -and the next morning I returned to finish the latter station. I -succeeded in sketching the detailed topography just south of the pass, -but shortly after noon, a furious storm arose similar to the one the day -before, and made further topographic work impossible; to get connection -farther on I patiently kept my eye to the eye-piece for more than an -hour after the storm had started, and was fortunate to catch the station -ahead in a single glimpse. I had a similar experience some days later at -station 16,079, Antabamba Quadrangle, on the rim of the high-level puna, -the storm preventing all topographic work and barely allowing a single -moment in which to catch a dim sight of the signals ahead while I kept -my eye steadily at the telescope to be ready for a favorable break in -the heavy clouds and hail.</p> - -<p>At Antabamba we got a new set of Indian carriers, who had orders to -accompany us to Cotahuasi, the next sub-prefectura. Raimondi’s map -indicates the distance between the two cities to be 35 miles, but -although nothing definite was stated, we found out in Antabamba that the -distance was considerably longer, and moreover that the entire route lay -at a high altitude.</p> - -<p>From the second day out of Antabamba until Huaynacotas was in sight in -the Cotahuasi Canyon, a distance of 50 miles, the route lay at an -altitude of from 16,000 to 17,630 feet, taking in 5 successive camps at -an altitude from 15,500 to 17,000 feet; 12 successive stations had the -following altitudes:</p> - -<table border="0" cellpadding="0" cellspacing="0" summary=""> -<tr><td align="left">16,379</td><td align="center">feet</td><td align="left"> </td></tr> -<tr><td align="left">16,852</td><td align="center">"</td><td align="left"> </td></tr> -<tr><td align="left">17,104</td><td align="center">"</td><td align="left"> </td></tr> -<tr><td align="left">17,559</td><td align="center">"</td><td align="left"> </td></tr> -<tr><td align="left">17,675</td><td align="center">"</td><td align="left">—highest station occupied.</td></tr> -<tr><td align="left">17,608</td><td align="center">"</td><td align="left"> </td></tr> -<tr><td align="left">17,633</td><td align="center">"</td><td align="left"> </td></tr> -<tr><td align="left">16,305</td><td align="center">"</td><td align="left"> </td></tr> -<tr><td align="left">17,630</td><td align="center">"</td><td align="left"> </td></tr> -<tr><td align="left">17,128</td><td align="center">"</td><td align="left"> </td></tr> -<tr><td align="left">16,794</td><td align="center">"</td><td align="left"> </td></tr> -<tr><td align="left">16,260</td><td align="center">"</td><td align="left"> </td></tr> -</table> - -<p><a name="page_317" id="page_317"></a></p> - -<p class="nind">The occupation of these high stations necessitated a great deal of -climbing, doubly hard in this rarefied air, and often on volcanoes with -a surface consisting of bowlders and ash and in the face of violent -hailstorms that made extremely difficult the task of connecting up -observations at successive stations.</p> - -<p>At Cotahuasi a new pack-train was organized, and on October 25th I -ventured to return alone to the high altitudes in order to continue the -topography at the station at 17,633 feet on the summit of the Maritime -Cordillera. Dr. Erving was obliged to leave on October 18th and -Professor Bowman left a week later in order to carry out his plans for a -physiographic study of the coast between Camaná and Mollendo. Philippi -Angulo, a native of Taurisma, a town above Cotahuasi, acted as majordomo -on this journey. Knowing the trail and the camp sites, I was able to -pick out the stations ahead myself, and made good progress, returning to -Cotahuasi on October 29th, three or four days earlier than planned. From -Cotahuasi to the coast I had the assistance of Mr. Watkins. The most -trying part of the last section of high altitude country was the great -Pampa Colorada, crowned by the snow-capped peaks of Solimana and -Coropuna, reaching heights of 20,730 and 21,703 feet respectively. The -passing of this pampa took seven days and we arrived at Chuquibamba on -November 9th. Two circumstances made the work on this stretch peculiarly -difficult—the scarcity of camping places and the high temperature in -the middle of the day, which heated the rarefied air to a degree that -made long-distance shots very strenuous work for the eyes. Although our -base signals were stone piles higher than a man, I was often forced to -keep my eye to the telescope for hours to catch a glimpse of the -signals; lack of time did not allow me to stop the telescope work in the -hottest part of the day.</p> - -<p>The top of Coropuna was intersected from the four stations: 16,344, -15,545, 16,168, and 16,664 feet elevation, the intersections giving a -very small triangular error. The elevation of Mount Coropuna’s high peak -as computed from these 4 stations is:</p> - -<table border="0" cellpadding="0" cellspacing="0" summary=""> -<tr><td> </td><td align="center"> 21,696 feet</td></tr> -<tr><td></td><td align="center">21,746 "</td></tr> -<tr><td></td><td align="center">21,714 "</td></tr> -<tr><td></td><td align="center"> -<span style="border-bottom:1px solid black;">21,657</span> "</td></tr> -<tr><td></td><td align="center" colspan="2">Mean elevation 21,703 feet above sea level.</td></tr> -</table> - -<p>The elevation of Coropuna as derived from these four stations has thus a -mean error of 18 feet (method of least squares) while the elevation of -each of the four stations as carried up from mean sea level through 25 -stations—vertical angles being observed in both directions—has an -estimated<a name="page_318" id="page_318"></a> mean error of 30 feet. The result of this is a mean error of -35 feet in Coropuna’s elevation above mean sea level.</p> - -<p>The latitude is 15° 31′ 00″ S.; the longitude is 72° 42′ 40″ W. of -Greenwich, the checking of these two determinations giving a result -unexpectedly close.</p> - -<p>On November 11th azimuth and latitude observations were taken at -Chuquibamba and two days later we arrived at Aplao in the bottom of the -splendid Majes Valley. In the northern part of this valley I was -prevented from doing any plane-table work in the afternoons of four -successive days. A strong gale set in each noon raising a regular -sandstorm, that made seeing almost impossible, and blowing with such a -velocity that it was impossible to set up the plane-table.</p> - -<p>From Hacienda Cantas to Camaná we had to pass the western desert for a -distance of 45 miles. We were told that on the entire distance there was -only one camping place. This was at Jaguey de Majes, where there was a -brook with just enough water for the animals but no fodder. Thus we -faced the necessity of carrying water for ten men and fodder for 14 -animals in excess of the usual cargo; and we were unable to foretell how -many days the topography over the hot desert would require.</p> - -<p>Although plane-table work in the desert was impossible at all except in -the earliest and latest hours of the day, we made regular progress. We -camped three nights at Jaguey and arrived on the fourth day at Las -Lomas.</p> - -<p>The next morning, on November 23rd, at an elevation of 2178 feet near -the crest of the Coast Range, we were repaid for two months of laborious -work by a glorious view of the Pacific Ocean and of the city of Camaná -with her olive gardens in the midst of the desert sand.</p> - -<p>The next day I observed latitude and azimuth at Camaná and in the night -my companion and assistant Mr. Watkins and I returned across the desert -to the railroad at Vitor.</p> - -<h4><span class="smcap">Conclusions</span></h4> - -<p>The planned methods were followed very closely. In two cases only the -plane-table had to be oriented by the magnetic needle, the backsights -not being obtainable because of the impossibility of locating the last -station, passing Indians having removed the signals.</p> - -<p>In one case only the distance between two stations had to be determined -by graphic triangulation exclusively, the base signals having been -destroyed. Otherwise graphic triangulation was used as a check on -distances.</p> - -<p>Vertical angles were always measured in both directions with the -exception of the above-mentioned cases.</p> - -<p>Observations for azimuth were always taken to the sun before and<a name="page_319" id="page_319"></a> after -noon. The direction used in the azimuth observation was also taken with -the prismatic compass. The mean of the magnetic declination thus found -is: East 8° 30′ plus.</p> - -<p>Observations for latitude were taken to the sun by the method of -circum-meridian altitudes, except at the town of Vilcabamba where star -observations were taken.</p> - -<p>As a matter of course, observations to the sun are not so exact as star -observations, especially in low latitudes where one can expect to -observe the near zenith. However, working in high altitudes for long -periods, moving camp every day and often arriving at camp 2 to 4 hours -after sunset, I found it essential to have undisturbed rest at night. It -was beyond my capacity to spend an hour or two of the night in finding -the meridian and in making the observation. Furthermore, the astronomic -observations were to check the topography mainly, the latter being the -most exact method with the outfit at hand.</p> - -<p>The following table contains the comparisons between the latitude -stations as located on the map and by observation:</p> - -<table border="0" cellpadding="4" cellspacing="0" summary=""> -<tr><td> </td><td align="center">Map</td><td align="center">Observation</td></tr> -<tr><td>Camaná Quadrangle S</td><td align="center">16° 37′ 34″</td><td align="center">16° 37′ 34″<a name="FNanchor_66_66" id="FNanchor_66_66"></a><a href="#Footnote_66_66" class="fnanchor">[66]</a></td></tr> -<tr><td>Coropuna, station 9,691S</td><td align="center">15° 48′ 30″</td><td align="center">(15° 51′ 44″) </td></tr> -<tr><td>Cotahuasi, " 12,588S</td><td align="center">15° 11′ 40″</td><td align="center">15° 12′ 30″ </td></tr> -<tr><td>La Cumbre, " 16,852S</td><td align="center">14° 28′ 10″</td><td align="center">14° 29′ 46″ </td></tr> -<tr><td>Lambrama, " 8,341S</td><td align="center">13° 43′ 18″</td><td align="center">13° 43′ 14″ </td></tr> -</table> - -<p>The other observations, with the exception of the one on the Coropuna -Quadrangle, check probably as well as can be expected with the small and -light outfit which we used, and under the exceptionally hard conditions -of work. The observation on the Coropuna Quadrangle just south of -Chuquibamba is, however, too much out. An explanation for this is that -the meridian zenith distance was 1° 23′ 12″ only (in this case the exact -formula was used in computing). Of course, an error or an accumulation -of errors might have been made in the distances taken by the -micrometer-alidade, but the first cause of error mentioned is the more -probable, and this is indicated also by the fact that the location on -the top of Mount Coropuna checks closely with the one determined in an -entirely independent way by the railroad engineers.</p> - -<p>For the cross-section map from Abancay to Camaná, the following -statistics are desirable:<a name="page_320" id="page_320"></a></p> - -<p>Micrometer traverse and graphic triangulation, with contours, field -scale 1:90,000.</p> - -<table border="0" cellpadding="1" cellspacing="0" summary=""> -<tr><td>Total time required, days</td><td align="right">40.5 </td></tr> -<tr><td>Average distance per days in miles</td><td align="right">7.5 </td></tr> -<tr><td>Average number of plane-table stations occupied per day</td><td align="right">1.5 </td></tr> -<tr><td>Average area per day in square miles</td><td align="right">38. </td></tr> -<tr><td>Located points per square mile</td><td align="right">0.25</td></tr> -<tr><td>Approximate elevations in excess of above, per square mile</td><td align="right">0.25</td></tr> -<tr><td>Highest station occupied, feet above sea level</td><td align="right">17,675. </td></tr> -<tr><td>Highest point located, feet above sea level</td><td align="right">21,703. </td></tr> -</table> - -<p><a name="page_321" id="page_321"></a></p> - -<h3><a name="APPENDIX_B" id="APPENDIX_B"></a>APPENDIX B<br /><br /> -<span class="smcap">Fossil Determinations</span></h3> - -<p>A few fossil collections were gathered in order that age determinations -might be made. With the following identifications I have included a few -fossils (I and II) collected by W. R. Rumbold and put into my hands in -1907. The Silurian is from a Bolivian locality south of La Paz but in -the great belt of shales, slates, and schists which forms one of the -oldest sedimentary series in the Eastern Andes of Peru as well as -Bolivia. While no fossils were found in this series in Peru the rocks -are provisionally referred to the Silurian. Fossil-bearing Carboniferous -overlies them but no other indication of their age was obtained save -their general position in the belt of schists already mentioned. I am -indebted to Professor Charles Schuchert of Yale University for the -following determinations.</p> - -<h4>I. <i>Silurian</i></h4> - -<p>San Roque Mine, southwest slope of Santa Vela Cruz, Canton Ichocu, Province -Inquisivi, Bolivia.</p> - -<p>Sent by William R. Rumbold in 1907.</p> - -<ul><li><i>Climacograptus?</i></li> -<li><i>Pholidops trombetana</i> Clarke?</li> -<li><i>Chonetes striatellus</i> (Dalman).</li> -<li><i>Atrypa marginalis</i> (Dalman)?</li> -<li><i>CÅ“lospira</i> n. sp.</li> -<li><i>Ctenodonta</i>, 2 or more species.</li> -<li><i>Hyolithes.</i></li> -<li><i>KlÅ“denia.</i></li> -<li><i>Calymene?</i></li> -<li><i>Dalmanites</i>, a large species with a terminal tail spine.</li> -<li><i>Acidaspis.</i></li></ul> - -<p>These fossils indicate unmistakably Silurian and probably Middle -Silurian. As all are from blue-black shales, brachiopods are the rarer -fossils, while bivalves and trilobites are the common forms. The faunal -aspect does not suggest relationship with that of Brazil as described by -J. M. Clarke and not at all with that of North America. I believe this -is the first time that Silurian fossils have been discovered in the high -Andes.</p> - -<h4>II. <span class="smcap">Lower Devonian</span></h4> - -<p>Near north end of Lake Titicaca.</p> - -<ul><li><i>LeptocÅ“lia flabellites</i> (Conrad), very common.</li> -<li><i>Atrypa reticularis</i> (Linnæus)?</li> -</ul> - -<p><a name="page_322" id="page_322"></a></p> - -<p>This is a part of the well-known and widely distributed Lower Devonian -fauna of the southern hemisphere.</p> - -<h4>III. <i>Upper Carboniferous</i></h4> - -<p>All of the Upper Carboniferous lots of fossils represent the well-known -South American fauna first noted by d’Orbigny in 1842, and later added -to by Orville Derby. The time represented is the equivalent of the -Pennsylvanian of North America.</p> - -<p>Huascatay between Pasaje and Huancarama.</p> - -<ul><li>Crinoidal limestone.</li> -<li>Trepostomata Bryozoa.</li> -<li><i>Polypora.</i> Common.</li> -<li><i>Streptorhynchus hallianus</i> Derby. Common.</li> -<li><i>Chonetes glaber</i> Geinitz. Rare.</li> -<li><i>Productus humboldti</i> d’Orb. Rare.</li> -<li> <span class="ditto">"</span> <i>cora</i> d’Orb. Rare.</li> -<li> <span class="ditto">"</span> <i>chandlessii</i> Derby.</li> -<li> <span class="ditto">"</span> sp. undet. Common.</li> -<li> <span class="ditto">"</span> sp. undet. "</li> -<li><i>Spirifer condor</i> d’Orb. Common.</li> -<li><i>Hustedia mormoni</i> (Marcou). Rare.</li> -<li><i>Seminula argentea</i> (Shepard). "</li></ul> - -<p>Pampaconas, Pampaconas valley near Vilcabamba.</p> - -<ul><li><i>Lophophyllum?</i></li> -<li><i>Rhombopora</i>, etc.</li> -<li><i>Productus.</i></li> -<li><i>Camarophoria.</i> Common.</li> -<li><i>Spirifer condor</i> d’Orb.</li> -<li><i>Hustedia mormoni</i> (Marcou).</li> -<li><i>Euomphalus.</i> Large form.</li></ul> - -<p>Pongo de Mainique. Extreme eastern edge of Peruvian Cordillera.</p> - -<ul><li><i>Lophophyllum.</i></li> -<li><i>Productus chandlessii</i> Derby.</li> -<li> <span class="ditto">"</span> <i>cora</i> d’Orb.</li> -<li><i>Orthotetes correanus</i> (Derby).</li> -<li><i>Spirifer condor</i> d’Orb.</li></ul> - -<p>River bowlders and stones of Urubamba river, just beyond eastern edge of -Cordillera at mouth of Ticumpinea river. (Detached and transported by stream -action from the Upper Carboniferous at Pongo de Mainique.)</p> - -<ul><li>Mostly Trepostomata Bryozoa.</li> -<li>Many <i>Productus</i> spines.</li> -<li><i>Productus cora</i> d’Orb.</li> -<li><i>Camarophoria</i>. Same as at Pampaconas.</li> -<li><i>Productus</i> sp. undet.</li></ul> - -<p>Cotahuasi A.</p> - -<ul><li><i>Lophophyllum.</i></li> -<li><i>Productus peruvianus</i> d’Orb.</li> -<li> <span class="ditto">"</span> sp. undet.</li> -<li><i>Camarophoria.</i><a name="page_323" id="page_323"></a></li> -<li><i>Pugnax</i> near <i>utah</i> (Marcou).</li> -<li><i>Seminula argentea</i> (Shepard)?</li></ul> - -<p>Cotahuasi B.</p> - -<ul><li><i>Productus cora</i> d’Orb.</li> -<li> <span class="ditto">"</span> near <i>semireticulatus</i> (Martin).</li></ul> - -<h4>IV. <i>Comanchian or Lower Cretaceous</i></h4> - -<p>Near Chuquibambilla.</p> - -<ul><li><i>Pecten</i> near <i>quadricostatus</i> Sowerby.</li> -<li>Undet. bivalves and gastropods.</li> -<li>The echinid <i>Laganum? colombianum</i> d’Orb. A clypeasterid.</li></ul> - -<p>This Lower Cretaceous locality is evidently of the same horizon as that -of Colombia illustrated by d’Orbigny in 1842 and described on pages -63-105.<a name="page_324" id="page_324"></a></p> - -<h3><a name="APPENDIX_C" id="APPENDIX_C"></a>APPENDIX C<br /><br /> -KEY TO PLACE NAMES</h3> - -<p class="c"><a href="#A">A</a>, -<a href="#C">C</a>, -<a href="#E">E</a>, -<a href="#H">H</a>, -<a href="#J">J</a>, -<a href="#L">L</a>, -<a href="#M">M</a>, -<a href="#O">O</a>, -<a href="#P">P</a>, -<a href="#Q">Q</a>, -<a href="#R">R</a>, -<a href="#S">S</a>, -<a href="#T">T</a>, -<a href="#U">U</a>, -<a href="#V">V</a>, -<a href="#Y">Y</a></p> - -<p class="nind"><br /> -<a name="A" id="A"></a>Abancay, town, lat. 12° 35′, Figs. <a href="#fig_20">20</a>, <a href="#fig_204">204</a>. -<br /> -Abra Tocate, pass, between Yavero and Urubamba valleys, leaving latter at Rosalina, (Fig. <a href="#fig_8">8</a>).<br /> - <i>See also</i> Fig. <a href="#fig_55">55</a>. -<br /> -Anta, town, lat. 13° 30′, Fig. <a href="#fig_20">20</a>. -<br /> -Antabamba, town, lat. 14° 20′, Figs. <a href="#fig_20">20</a>, <a href="#fig_204">204</a>. -<br /> -Aplao, town, lat. 16°, Figs. <a href="#fig_20">20</a>, <a href="#fig_204">204</a>. -<br /> -Apurimac, river, Fig. <a href="#fig_20">20</a>. -<br /> -Arequipa, town, lat. 16° 30′, Fig. <a href="#fig_66">66</a>. -<br /> -Arica, town, northern Chile, lat. 18° 30′. -<br /> -Arma, river, tributary of Apurimac, lat. 13° 25′, (Fig. <a href="#fig_20">20</a>); - tributary of Ocoña, lat. 15° 30′, (Fig. <a href="#fig_20">20</a>). -<br /> -Arma, village, lat. 13° 15′, Fig. <a href="#fig_20">20</a>.<br /> - <i>See also</i> Fig. <a href="#fig_140">140</a>. -<br /> -Auquibamba, hacienda, lat. 13° 40′, Fig. <a href="#fig_204">204</a>. - -<br /> -<a name="C" id="C"></a>Callao, town, lat. 12°, Fig. <a href="#fig_66">66</a>. -<br /> -Camaná, town, lat. 16° 40′, Figs. <a href="#fig_20">20</a>, <a href="#fig_66">66</a>, <a href="#fig_204">204</a>. -<br /> -Camisea, river, tributary of Urubamba entering from right, lat. 11° 15′. -<br /> -Camp 13, lat. 14° 30′. -<br /> -Cantas, hacienda, lat. 16° 15′, Fig. <a href="#fig_204">204</a>. -<br /> -Caraveli, town, lat. 16°, Fig. <a href="#fig_66">66</a>. -<br /> -Catacaos, town, lat. 5° 30′, Fig. <a href="#fig_66">66</a>. -<br /> -Caylloma, town and mines, lat. 15° 30′, Fig. <a href="#fig_66">66</a>. -<br /> -Caypi, village, lat. 13° 45′. -<br /> -Central Ranges, lat. 14°, Fig. <a href="#fig_20">20</a>.<br /> - <i>See also</i> Fig. <a href="#fig_157">157</a>. -<br /> -Cerro Azul, town, lat. 13°, Fig. <a href="#fig_66">66</a>. -<br /> -Chachani, mt., overlooking Arequipa, lat. 16° 30′, (Fig. <a href="#fig_66">66</a>). -<br /> -Chaupimayu, river, tributary of Urubamba entering at Sahuayaco, <i>q.v.</i> -<br /> -Chili, river, tributary of Vitor River, lat. 16° 30′, (Fig. <a href="#fig_66">66</a>). -<br /> -Chinche, hacienda, Urubamba Valley above Santa Ana, lat. 13°, (Fig. <a href="#fig_20">20</a>). -<br /> -Chira, river, lat. 5°, Fig. <a href="#fig_66">66</a>. -<br /> -Choclococha, lake, lat. 13° 30′, Figs. <a href="#fig_66">66</a>, <a href="#fig_68">68</a>. -<br /> -Choqquequirau, ruins, canyon of Apurimac above junction of Pachachaca River, lat. 13° 25′, (Fig. <a href="#fig_20">20</a>). -<br /> -Choquetira, village, lat. 13° 20′, Fig. <a href="#fig_20">20</a>.<br /> - <i>See also</i> Fig. <a href="#fig_136">136</a>. -<br /> -Chosica, village, lat. 12°, Fig. <a href="#fig_66">66</a>. -<br /> -Chuquibamba, town, lat. 15° 50′, Figs. <a href="#fig_20">20</a>, <a href="#fig_204">204</a>. -<br /> -Chuquibambilla, village, lat. 14°, Figs. <a href="#fig_20">20</a>, <a href="#fig_204">204</a>. -<br /> -Chuquito, pass, Cordillera Vilcapampa between Arma and Vilcabamba valleys, lat. 13° 10′, (Fig. <a href="#fig_20">20</a>).<br /> - <i>See also</i> Fig. <a href="#fig_139">139</a>. -<br /> -Coast Range, Figs. <a href="#fig_66">66</a>, <a href="#fig_204">204</a>. -<br /> -Cochabamba, city, Bolivia, lat. 17° 20′, long. 66° 20′. -<br /> -Colorada, pampa, lat. 15° 30′, Fig. <a href="#fig_204">204</a>. -<br /> -Colpani, village, lower end of Canyon of Torontoy (Urubamba River), lat. 13° 10′. <i>See</i> Fig. <a href="#fig_158">158</a>. -<br /> -Copacavana, village, Bolivia, lat. 16° 10′, long. 69° 10′. -<br /> -Coribeni, river, lat. 12° 40′, Fig. <a href="#fig_8">8</a>. -<br /> -Coropuna, mt., lat. 15° 30′, Figs. <a href="#fig_20">20</a>, <a href="#fig_204">204</a>. -<br /> -Corralpata, village, Apurimac Valley near Incahuasi. -<br /> -Cosos, village, lat. 16°, Fig. <a href="#fig_204">204</a>. -<br /> -Cotabambas, town, Apurimac Valley, lat. 13° 45′, (Fig. <a href="#fig_20">20</a>). -<br /> -Cotahuasi, town, lat. 15° 10′, Figs. <a href="#fig_20">20</a>, <a href="#fig_204">204</a>. -<br /> -Cuzco, city, lat. 13° 30′, Fig. <a href="#fig_20">20</a>. - -<br /> -<a name="E" id="E"></a>Echarati, hacienda, on the Urubamba River between Santa Ana and Rosalina, lat. 12° 40′.<br /> - <i>See</i> inset map, Fig. <a href="#fig_8">8</a>, <i>and also</i> Fig. <a href="#fig_54">54</a>. - -<br /> -<a name="H" id="H"></a>Huadquiña, hacienda, Urubamba River above junction with Vilcabamba, lat. 13° 10′, (Fig. <a href="#fig_20">20</a>).<br /> - <i>See also</i> Fig. <a href="#fig_158">158</a>. -<br /> -Huadquirca, village, lat. 14° 15′, Figs. <a href="#fig_20">20</a>, <a href="#fig_204">204</a>. -<br /> -Huaipo, lake, north of Anta, lat. 13° 25′, (Fig. <a href="#fig_20">20</a>). -<br /> -Huambo, village, left bank Pachachaca River between Huancarama and Pasaje, lat. 13° 35′, (Fig. <a href="#fig_20">20</a>). -<br /> -Huancarama, town, lat. 13° 40′, Fig. <a href="#fig_20">20</a>. -<br /> -Huancarqui, village, lat. 16° 5′, Fig. <a href="#fig_204">204</a>. -<br /> -Huascatay, village, left bank of Apurimac above Pasaje, lat. 13° 30′, (Fig. <a href="#fig_20">20</a>). -<br /> -Huaynacotas, village, lat. 15° 10′, Fig. <a href="#fig_204">204</a>. -<br /> -Huichihua, village, lat. 14° 10′, Fig. <a href="#fig_204">204</a>. - -(Tablazo de) Ica, plateau, lat. 14°-15° 30′, Fig. <a href="#fig_66">66</a>. -<br /> -Ica, town, lat. 14°, Figs. <a href="#fig_66">66</a>, <a href="#fig_67">67</a>. -<br /> -Incahuasi, village, lat. 13° 20′, Fig. <a href="#fig_20">20</a>. -<br /> -Iquique, town, northern Chile, lat. 20° 15′. - -(Pampa de) Islay, south of Vitor River, (Fig. <a href="#fig_66">66</a>). - -<br /> -<a name="J" id="J"></a>Jaguey, village, Pampa de Sihuas, <i>q.v.</i> - -<br /> -<a name="L" id="L"></a>La Joya, pampa, station on Mollendo-Puno R.R., 16° 40′, (Fig. <a href="#fig_66">66</a>). -<br /> -Lambrama, village, lat. 12° 50′, Fig. <a href="#fig_20">20</a>. -<br /> -Lima, city, lat. 12°, Fig. <a href="#fig_66">66</a>. - -<br /> -<a name="M" id="M"></a>Machu Picchu, ruins, gorge of Torontoy, <i>q.v.</i>, lat. 13° 10′. -<br /> -Majes, river, Fig. <a href="#fig_204">204</a>. -<br /> -Manugali, river, tributary of Urubamba entering from left above Puviriari River, lat. 12° 20′, (Fig. <a href="#fig_8">8</a>). -<br /> -Maritime Cordillera, Fig. <a href="#fig_204">204</a>. -<br /> -Matara, village, lat. 14° 20′, Fig. <a href="#fig_204">204</a>. - -(El) Misti, mt., lat. 16° 30′, Fig. <a href="#fig_66">66</a>. -<br /> -Mollendo, town, lat. 17°, Fig. <a href="#fig_66">66</a>. -<br /> -Moquegua, town, lat. 17°, Fig. <a href="#fig_66">66</a>. -<br /> -Morococha, mines, lat. 11° 45′, Fig. <a href="#fig_66">66</a>. -<br /> -Mulanquiato, settlement, lat. 12° 10′, Fig. <a href="#fig_8">8</a>. - -<br /> -<a name="O" id="O"></a>Occobamba, river, uniting with Yanatili, <i>q.v.</i> -<br /> -Ocoña, river, lat. 15°-16° 30′, Figs. <a href="#fig_20">20</a>, <a href="#fig_66">66</a>. -<br /> -Ollantaytambo, village. Urubamba River below Urubamba town, lat. 13° 15′, (Fig. <a href="#fig_20">20</a>), <i>and see</i> inset map, Fig. <a href="#fig_8">8</a>. - -<br /> -<a name="P" id="P"></a>Pabellon, hacienda, Urubamba River above Rosalina, (Fig. <a href="#fig_20">20</a>).<br /> - <i>See also</i> Fig. <a href="#fig_55">55</a>. -<br /> -Pacasmayo, town, lat. 7° 30′, Fig. <a href="#fig_66">66</a>. -<br /> -Pachatusca (Pachatusun), mt., overlooking Cuzco to northeast, lat. 13° 30′. -<br /> -Pachitea, river, tributary of Ucayali entering from left, lat. 8° 50′. -<br /> -Paita, town, lat. 5°, Fig. <a href="#fig_66">66</a>. -<br /> -Pampacolea, village, south of Coropuna, <i>q.v.</i> -<br /> -Pampaconas, river, known in lower course as Cosireni, tributary of Urubamba River, (Fig. <a href="#fig_8">8</a>). - Source in Cordillera Vilcapampa west of Vilcabamba. -<br /> -Pampas, river, tributary of Apurimac entering from left, lat. 13° 20′. -<br /> -Panta, mt., Cordillera Vilcapampa, northwest of Arma, lat. 13° 15′, (Fig. <a href="#fig_20">20</a>).<br /> - <i>See also</i> Fig. <a href="#fig_136">136</a>. -<br /> -Panticalla, pass, Urubamba Valley above Torontoy, lat. 13° 10′. -<br /> -Pasaje, hacienda and ferry, lat. 13° 30′, Fig. <a href="#fig_20">20</a>. -<br /> -Paucartambo (Yavero), river, <i>q.v.</i> -<br /> -Paucartambo, town, head of Paucartambo (Yavero) River, lat. 13° 20′, long. 71° 40′. Inset map, Fig. <a href="#fig_8">8</a>. -<br /> -Pichu-Pichu, mt., overlooking Arequipa, lat. 16°, (Fig. <a href="#fig_66">66</a>). -<br /> -Pilcopata, river, tributary of Upper Madre de Dios east of Paucartambo, lat. 13°. -<br /> -Piñi-piñi, river, tributary of Upper Madre de Dios east of Paucartambo, lat. 13°. -<br /> -Pisco, town, lat. 14°, Fig. <a href="#fig_66">66</a>. -<br /> -Piura, river, lat. 5°-6°, Fig. <a href="#fig_66">66</a>. -<br /> -Piura, town, lat. 5° 30′, Fig. <a href="#fig_66">66</a>. -<br /> -Pomareni, river, lat. 12°, Fig. <a href="#fig_8">8</a>. -<br /> -Pongo de Mainique, rapids, lat. 12°, Fig. <a href="#fig_8">8</a>. -<br /> -Pucamoco, hacienda, Urubamba River, between Santa Ana and Rosalina, (Fig. <a href="#fig_20">20</a>). -<br /> -Puquiura, village, lat. 13° 5′, Fig. <a href="#fig_20">20</a>.<br /> - <i>See also</i> Fig. <a href="#fig_158">158</a>. Distinguish Puqura in Anta basin near Cuzco. -<br /> -Puqura, village, Anta basin, east of Anta, lat. 13° 30′, (Fig. <a href="#fig_20">20</a>). - -<br /> -<a name="Q" id="Q"></a>Quilca, town, lat. 16° 40′, Fig. <a href="#fig_66">66</a>. -<br /> -Quillagua, village, northern Chile, lat. 21° 30′, long. 69° 35′. - -<br /> -<a name="R" id="R"></a>Rosalina, settlement, lat. 12° 35′, Fig. <a href="#fig_8">8</a>.<br /> - <i>See also</i> Fig. <a href="#fig_20">20</a>. - -<br /> -<a name="S" id="S"></a>Sahuayaco, hacienda, Urubamba Valley above Rosalina, (Fig. <a href="#fig_20">20</a>).<br /> - <i>See also</i> Fig. <a href="#fig_55">55</a>. -<br /> -Salamanca, town, lat. 15° 30′, Fig. <a href="#fig_20">20</a>. -<br /> -Salaverry, town, lat. 8°, Fig. <a href="#fig_66">66</a>. -<br /> -Salcantay, mt., lat. 13° 20′, Fig. <a href="#fig_20">20</a>. -<br /> -San Miguel, bridge, canyon of Torontoy near Machu Picchu, lat. 13° 10′. -<br /> -Santa Ana, hacienda, lat. 12° 50′, Fig. <a href="#fig_20">20</a>. -<br /> -Santa Ana, river, name applied to the Urubamba in the region about hacienda Santa Ana. -<br /> -Santa Lucia, mines, lat. 16°, Fig. <a href="#fig_66">66</a>. -<br /> -Santo Anato, hacienda, La Sama’s hut, 12° 35′, Fig. <a href="#fig_8">8</a>. -<br /> -Sihuas, Pampa de, lat. 16° 30′, Fig. <a href="#fig_204">204</a>. -<br /> -Sillilica, Cordillera, east of Iquique, northern Chile. -<br /> -Sintulini, rapids of Urubamba River above junction of Pomareni, lat. 12° 10′, (Fig. <a href="#fig_8">8</a>). -<br /> -Sirialo, river, lat. 12° 40′, Fig. <a href="#fig_8">8</a>. -<br /> -Soiroccocha, mt., Cordillera Vilcapampa north of Arma, lat. 13° 15′, (Fig. <a href="#fig_20">20</a>). -<br /> -Solimana, mt., lat. 15° 20′, Fig. <a href="#fig_204">204</a>. -<br /> -Soray, mt., Cordillera Vilcapampa, southeast of Mt. Salcantay, lat. 13° 20′, (Fig. <a href="#fig_20">20</a>). -<br /> -Sotospampa, village, near Lambrama, lat. 13° 50′, (Fig. <a href="#fig_204">204</a>). -<br /> -Sullana, town, Chira River, lat. 5°, (Fig. <a href="#fig_66">66</a>). - -<br /> -<a name="T" id="T"></a>Taurisma, village, lat. 15° 10′, Fig. <a href="#fig_204">204</a>. -<br /> -Ticumpinea, river, tributary of Urubamba entering from right below Pongo de Mainique, lat. 11° 50′, (Fig. <a href="#fig_8">8</a>). -<br /> -Timpia, river, tributary of Urubamba entering from right, lat. 11° 45′. -<br /> -Tono, river, tributary of Upper Madre de Dios, east of Paucartambo, lat. 13°. -<br /> -Torontoy, canyon of the Urubamba between the villages of Torontoy and Colpani, lat. 13° 10′-13° 15′. -<br /> -Torontoy, village at the head of the canyon of the same name, lat. 13° 15′.<br /> - <i>See</i> inset map, Fig. <a href="#fig_8">8</a>. -<br /> -Tumbez, town, lat. 4° 30′, Fig. <a href="#fig_66">66</a>. -<br /> -Tunari, Cerro de, mt., northwest of Cochabamba, <i>q.v.</i> - -<br /> -<a name="U" id="U"></a>Urubamba, river, Fig. <a href="#fig_20">20</a>. -<br /> -Urubamba, town, lat. 13° 20′, Fig. <a href="#fig_20">20</a>. - -<br /> -<a name="V" id="V"></a>Vilcabamba, river, tributary of Urubamba River entering from left above Santa Ana, lat. 13°, Fig. <a href="#fig_8">8</a>.<br /> - <i>See also</i> Fig. <a href="#fig_158">158</a>. -<br /> -Vilcabamba, village, lat. 13° 5′, Fig. <a href="#fig_20">20</a>.<br /> - <i>See also</i> Fig. <a href="#fig_158">158</a>. -<br /> -Vilcanota, Cordillera, southern Peru. -<br /> -Vilcanota, river, name applied to Urubamba above lat. of Cuzco, 13° 30′, (Fig. <a href="#fig_20">20</a>). -<br /> -Vilcapampa, Cordillera, lat. 13° 20′, Fig. <a href="#fig_20">20</a>. -<br /> -Vilque, town, southern Peru, lat. 15° 50′, long. 70° 30′. -<br /> -Vitor, pampa, lat. 16° 30′, Fig. <a href="#fig_66">66</a>. -<br /> -Vitor, river, Fig. <a href="#fig_66">66</a>. - -<br /> -<a name="Y" id="Y"></a>Yanahuara, pass, between Urubamba and Yanatili valleys, lat. 13° 10′. -<br /> -Yanatili, river, tributary of Urubamba entering from right above Rosalina, (Fig. <a href="#fig_20">20</a>).<br /> - <i>See also</i> Fig. <a href="#fig_65">65</a>. -<br /> -Yavero (Paucartambo), river, tributary of Urubamba entering from right, lat. 12° 10′, Fig. <a href="#fig_8">8</a>. -<br /> -Yavero, settlement, at junction of Yavero and Urubamba rivers, lat. 12° 10′, Fig. <a href="#fig_8">8</a>. -<br /> -Yunguyo, town, southern Peru, lat. 16° 20′, long. 69° 10′. -<br /> -Yuyato, river, lat. 12° 5′, Fig. <a href="#fig_8">8</a>. -</p> - -<p><a name="page_327" id="page_327"></a></p> - -<h3><a name="INDEX" id="INDEX"></a>INDEX</h3> - -<p class="c"><a href="#A-2">A</a>, -<a href="#B-2">B</a>, -<a href="#C-2">C</a>, -<a href="#D-2">D</a>, -<a href="#E-2">E</a>, -<a href="#F-2">F</a>, -<a href="#G-2">G</a>, -<a href="#H-2">H</a>, -<a href="#I-2">I</a>, -<a href="#J-2">J</a>, -<a href="#K-2">K</a>, -<a href="#L-2">L</a>, -<a href="#M-2">M</a>, -<a href="#N-2">N</a>, -<a href="#O-2">O</a>, -<a href="#P-2">P</a>, -<a href="#Q-2">Q</a>, -<a href="#R-2">R</a>, -<a href="#S-2">S</a>, -<a href="#T-2">T</a>, -<a href="#U-2">U</a>, -<a href="#V-2">V</a>, -<a href="#W-2">W</a>, -<a href="#Y-2">Y</a></p> - -<p class="nind"> -<a name="A-2" id="A-2"></a>Abancay, <a href="#page_032">32</a>, <a href="#page_062">62</a>, <a href="#page_064">64</a>, <a href="#page_078">78</a>, <a href="#page_092">92</a>, <a href="#page_093">93</a>, <a href="#page_181">181</a>, <a href="#page_189">189</a>, <a href="#page_221">221</a>, <a href="#page_243">243</a>;<br /> -<span style="margin-left: 1em;">suppressing a revolution, <a href="#page_089">89-91</a>;</span><br /> -<span style="margin-left: 1em;">temperature curve (diagr.), opp. p. <a href="#page_180">180</a></span><br /> - -Abancay basin, <a href="#page_154">154</a><br /> - -Abancay to Camaná cross-section map, work, observation and statistics, <a href="#page_315">315</a><br /> - -Abra Tocate, <a href="#page_073">73</a>, <a href="#page_080">80</a>, <a href="#page_081">81</a>;<br /> -<span style="margin-left: 1em;">topography and vegetation from (ill.), opp. p. <a href="#page_019">19</a></span><br /> - -Abra de Malaga, <a href="#page_276">276</a><br /> - -Acosta, <a href="#page_205">205</a><br /> - -Adams, G. I., <a href="#page_255">255</a><br /> - -Agriculture, <a href="#page_074">74-76</a>, <a href="#page_152">152</a><br /> - -Aguardiente, <a href="#page_074">74</a>. <i>See</i> Brandy<br /> - -Alcohol, <a href="#page_005">5</a>, <a href="#page_006">6</a><br /> - -Alluvial fans, <a href="#page_060">60-63</a>, <a href="#page_070">70</a>, <a href="#page_270">270</a><br /> - -Alluvial fill, <a href="#page_270">270-273</a>;<br /> -<span style="margin-left: 1em;">view in Majes Valley (ill.), opp. p. <a href="#page_230">230</a></span><br /> - -Alpacas, <a href="#page_005">5</a>, <a href="#page_052">52</a><br /> - -Alto de los Huesos (ill.), opp. p. <a href="#page_007">7</a><br /> - -Amazon basin, Humboldt’s dream of conquest, <a href="#page_033">33-35</a>;<br /> -<span style="margin-left: 1em;">Indian tribes, <a href="#page_036">36</a></span><br /> - -Amazonia, <a href="#page_020">20</a>, <a href="#page_026">26</a><br /> - -Ancachs, <a href="#page_171">171</a><br /> - -Andahuaylas, <a href="#page_089">89</a><br /> - -Andrews, A, C., <a href="#page_295">295</a><br /> - -Angulo, Philippi, <a href="#page_317">317</a><br /> - -Anta, <a href="#page_187">187</a>, <a href="#page_189">189</a>, <a href="#page_190">190</a><br /> - -Anta basin, <a href="#page_062">62</a>, <a href="#page_108">108</a>, <a href="#page_197">197</a>;<br /> -<span style="margin-left: 1em;">geology, <a href="#page_250">250</a>;</span><br /> -<span style="margin-left: 1em;">view looking north from hill near Anta (ill.), opp. p. <a href="#page_184">184</a></span><br /> - -Antabamba, <a href="#page_052">52</a>, <a href="#page_053">53</a>, <a href="#page_095">95</a>, <a href="#page_096">96</a>, <a href="#page_099">99</a>, <a href="#page_101">101</a>, <a href="#page_189">189</a>, <a href="#page_197">197</a>, <a href="#page_243">243</a>, <a href="#page_303">303</a>, <a href="#page_316">316</a>;<br /> -<span style="margin-left: 1em;">Governor, <a href="#page_095">95-99</a>, <a href="#page_100">100-101</a>;</span><br /> -<span style="margin-left: 1em;">Lieutenant Governor, <a href="#page_096">96-99</a>, <a href="#page_101">101</a>;</span><br /> -<span style="margin-left: 1em;">sketch section, <a href="#page_243">243</a></span><br /> - -Antabamba Canyon, view across (ill.), opp. p. <a href="#page_106">106</a><br /> - -Antabamba Quadrangle, <a href="#page_316">316</a>, opp. p. <a href="#page_282">282</a> (topog. sheet)<br /> - -Antabamba region, geologic sketch map and section, <a href="#page_245">245</a><br /> - -Antabamba Valley, <a href="#page_096">96</a><br /> - -“Antis,†<a href="#page_039">39</a><br /> - -Aplao, <a href="#page_106">106</a>, <a href="#page_115">115</a>, <a href="#page_116">116</a>, <a href="#page_181">181</a>, <a href="#page_226">226</a>, <a href="#page_231">231</a>, <a href="#page_255">255</a>, <a href="#page_256">256</a>, <a href="#page_257">257</a>, <a href="#page_273">273</a>, <a href="#page_318">318</a>;<br /> -<span style="margin-left: 1em;">composite structure section (diagr.), <a href="#page_259">259</a>;</span><br /> -<span style="margin-left: 1em;">temperature curve (diagr.), <a href="#page_181">181</a></span><br /> - -Aplao Quadrangle (topog. sheet), opp. p. <a href="#page_120">120</a><br /> - -Appendix A, <a href="#page_315">315</a><br /> - -Appendix B, <a href="#page_321">321</a><br /> - -Appendix C, <a href="#page_324">324</a><br /> - -Apurimac, <a href="#page_051">51</a>, <a href="#page_057">57</a>, <a href="#page_060">60</a>, <a href="#page_094">94</a>, <a href="#page_153">153</a>, <a href="#page_154">154</a>;<br /> -<span style="margin-left: 1em;">crossing at Pasaje (ills.), opp. p. <a href="#page_091">91</a>;</span><br /> -<span style="margin-left: 1em;">regional diagram of canyoned country, <a href="#page_058">58</a></span><br /> - -Apurimac Canyon, <a href="#page_189">189</a>;<br /> -<span style="margin-left: 1em;">cloud belt (ill.), opp. p. <a href="#page_150">150</a></span><br /> - -Arequipa, <a href="#page_052">52</a>, <a href="#page_089">89</a>, <a href="#page_092">92</a>, <a href="#page_117">117</a>, <a href="#page_120">120</a>, <a href="#page_137">137</a>, <a href="#page_284">284</a>;<br /> -<span style="margin-left: 1em;">glacial features near (sketches), <a href="#page_280">280</a></span><br /> - -Argentina, <a href="#page_093">93</a><br /> - -Arica, <a href="#page_130">130</a>, <a href="#page_132">132</a>, <a href="#page_198">198</a><br /> - -Arma, <a href="#page_067">67</a>, <a href="#page_189">189</a>, <a href="#page_212">212-214</a><br /> - -Arrieros, Pampa de, <a href="#page_280">280</a><br /> - -Asymmetrical peaks (ill.), opp. p. <a href="#page_281">281</a><br /> - -Asymmetry, <a href="#page_305">305-313</a>;<br /> -<span style="margin-left: 1em;">cross-section of ridge (diagr.), <a href="#page_306">306</a>;</span><br /> -<span style="margin-left: 1em;">postglacial volcano (diagr.), <a href="#page_306">306</a></span><br /> - -Auquibamba, <a href="#page_093">93</a><br /> - -Avalanches, <a href="#page_290">290</a><br /> - -<br /> -<a name="B-2" id="B-2"></a>Bailey, S. I., <a href="#page_284">284</a><br /> - -Bandits, <a href="#page_095">95</a><br /> - -Basins, <a href="#page_060">60</a>, <a href="#page_154">154</a>;<br /> -<span style="margin-left: 1em;">regional diagram, <a href="#page_061">61</a>;</span><br /> -<span style="margin-left: 1em;">climatic cross-section (diagr.), <a href="#page_062">62</a></span><br /> - -Batholith, Vilcapampa, <a href="#page_215">215-224</a><br /> - -Belaunde brothers, <a href="#page_116">116</a><br /> - -Bergschrunds, <a href="#page_294">294-305</a><br /> - -Bingham, Hiram, ix, <a href="#page_104">104</a>, <a href="#page_157">157</a><br /> - -Block diagram of physiography of Andes, <a href="#page_186">186</a><br /> - -Boatmen, Indian, <a href="#page_013">13</a><br /> - -Bogotá, Cordillera of, <a href="#page_205">205</a><br /> - -Bolivia, <a href="#page_093">93</a>, <a href="#page_176">176</a>, <a href="#page_190">190</a>, <a href="#page_193">193</a>, <a href="#page_195">195</a>, <a href="#page_240">240</a>, <a href="#page_241">241</a>, <a href="#page_249">249</a>, <a href="#page_322">322</a>;<br /> -<span style="margin-left: 1em;">snowline, <a href="#page_275">275-277</a></span><br /> - -Bolivian boundary, <a href="#page_068">68</a><br /> - -Border valleys of the Eastern Andes, <a href="#page_068">68-87</a><br /> - -Borneo, <a href="#page_206">206</a><br /> - -Bowman, Isaiah, <a href="#page_008">8</a>, <a href="#page_316">316</a><br /> - -Brandy, <a href="#page_074">74</a>, <a href="#page_075">75</a>, <a href="#page_076">76</a>, <a href="#page_082">82-83</a><br /> - -Bravo, José, <a href="#page_245">245</a><br /> - -Bumstead, A. H., ix<br /> - -<br /> -<a name="C-2" id="C-2"></a>Cacao, <a href="#page_074">74</a>, <a href="#page_083">83</a><br /> - -Cacti, <a href="#page_150">150</a>;<br /> -<span style="margin-left: 1em;">arboreal (ill.), opp. p. <a href="#page_090">90</a></span><br /> - -Calchaquà Valley, <a href="#page_250">250</a><br /> - -Callao, <a href="#page_118">118</a>;<br /> -<span style="margin-left: 1em;">cloudiness (with diagr.), <a href="#page_133">133</a>;</span><br /> -<span style="margin-left: 1em;">temperature (with diagr.), <a href="#page_126">126-129</a>;</span><br /> -<span style="margin-left: 1em;">wind roses (diagrs.), <a href="#page_128">128</a></span><br /> - -Camaná, <a href="#page_021">21</a>, <a href="#page_112">112</a>, <a href="#page_115">115</a>, <a href="#page_116">116</a>, <a href="#page_117">117</a>, <a href="#page_118">118</a>, <a href="#page_140">140-141</a>, <a href="#page_147">147</a>, <a href="#page_181">181</a>, <a href="#page_225">225</a>, <a href="#page_226">226</a>, <a href="#page_227">227</a>, <a href="#page_266">266</a>, <a href="#page_318">318</a>;<br /> -<span style="margin-left: 1em;">coastal Tertiary, <a href="#page_253">253</a>, <a href="#page_254">254</a>;</span><br /> -<span style="margin-left: 1em;">plain of, <a href="#page_229">229</a>;</span><br /> -<span style="margin-left: 1em;">temperature curve (diagr.), <a href="#page_181">181</a></span><br /> - -Camaná Quadrangle (topog. sheet), opp. p. <a href="#page_114">114</a><br /> - -Camaná Valley, <a href="#page_257">257</a><br /> - -Camaná-Vitor region, <a href="#page_117">117</a><br /> - -Camino del Peñon, <a href="#page_110">110</a><br /> - -Camisea, <a href="#page_036">36</a><br /> - -Camp <a href="#page_013">13</a>, <a href="#page_100">100</a>, <a href="#page_180">180</a>, <a href="#page_181">181</a>;<br /> -<span style="margin-left: 1em;">temperature curve (diagr.), <a href="#page_180">180</a></span><br /> - -Campas, <a href="#page_037">37</a><br /> - -Canals for bringing water, <a href="#page_059">59</a>, <a href="#page_060">60</a>, <a href="#page_155">155</a>;<br /> -<span style="margin-left: 1em;">projected, Maritime Cordillera (diagr.), <a href="#page_118">118</a></span><br /> - -Cantas, <a href="#page_115">115</a>, <a href="#page_116">116</a>, <a href="#page_226">226</a>, <a href="#page_253">253</a>, <a href="#page_257">257</a>, <a href="#page_273">273</a>, <a href="#page_318">318</a><br /> - -Canyon walls (ills.), opp. p. <a href="#page_218">218</a><br /> - -Canyoned country, regional diagram, <a href="#page_058">58</a>;<br /> -<span style="margin-left: 1em;">valley climates (diagr.), <a href="#page_059">59</a></span><br /> - -Canyons, <a href="#page_060">60</a>, <a href="#page_072">72</a>, <a href="#page_073">73</a>, <a href="#page_197">197</a>, <a href="#page_219">219</a>;<br /> -<span style="margin-left: 1em;">Majes River (ill.), opp. p. <a href="#page_230">230</a>;</span><br /> -<span style="margin-left: 1em;">topographic conditions before formation of deep canyons in Maritime Cordillera (ill.), opp. p. <a href="#page_184">184</a></span><br /> - -Caraveli, climate data, <a href="#page_134">134-136</a>;<br /> -<span style="margin-left: 1em;">wind roses (diagrs.), <a href="#page_136">136</a></span><br /> - -Carboniferous fossils, <a href="#page_323">323</a><br /> - -Carboniferous strata, <a href="#page_241">241-247</a>;<br /> -<span style="margin-left: 1em;">hypothetical distribution of land and sea (diagr.), <a href="#page_246">246</a></span><br /> - -Cashibos, <a href="#page_037">37</a><br /> - -Catacaos, <a href="#page_119">119</a><br /> - -Cattle tracks (ill.), opp. p. <a href="#page_226">226</a><br /> - -Caucho, <a href="#page_029">29</a><br /> - -Caylloma, <a href="#page_164">164</a>, <a href="#page_165">165</a><br /> - -Caypi, <a href="#page_316">316</a><br /> - -Central Ranges, asymmetrical peaks (ill.), opp. p. <a href="#page_281">281</a>;<br /> -<span style="margin-left: 1em;">glacial features with lateral moraines (ill.), opp. p. <a href="#page_269">269</a>;</span><br /> -<span style="margin-left: 1em;">glacial topography between Lambrama and Antabamba (ill.), opp. p. <a href="#page_280">280</a>;</span><br /> -<span style="margin-left: 1em;">steep cirque walls (ill.), opp. p. <a href="#page_286">286</a></span><br /> - -Cerro Azul, <a href="#page_118">118</a><br /> - -Cerro de Tunari, <a href="#page_176">176</a><br /> - -Chachani, <a href="#page_280">280</a>, <a href="#page_284">284</a><br /> - -Chanchamayo, <a href="#page_077">77</a><br /> - -Character. <i>See</i> Human character<br /> - -Chaupimayu Valley, <a href="#page_077">77</a><br /> - -<i>Chicha</i>, <a href="#page_086">86</a><br /> - -Chile, <a href="#page_130">130</a>, <a href="#page_132">132</a>, <a href="#page_193">193</a>, <a href="#page_260">260</a><br /> - -Chili River, <a href="#page_120">120</a><br /> - -Chili Valley, opp. p. <a href="#page_007">7</a> (ill.), <a href="#page_117">117</a><br /> - -Chimborazo, <a href="#page_281">281</a><br /> - -Chinche, <a href="#page_271">271</a>, <a href="#page_272">272</a><br /> - -Chira River, depth diagram, <a href="#page_119">119</a>, <a href="#page_120">120</a><br /> - -Chirumbia, <a href="#page_012">12</a><br /> - -Choclococha, Lake, <a href="#page_120">120</a><br /> - -Chonta Campas, <a href="#page_037">37</a><br /> - -Choqquequirau, <a href="#page_154">154</a><br /> - -Choquetira, <a href="#page_066">66</a>, <a href="#page_067">67</a>, <a href="#page_211">211</a>;<br /> -<span style="margin-left: 1em;">bowldery fill below, <a href="#page_269">269</a>;</span><br /> -<span style="margin-left: 1em;">glacial features, <a href="#page_206">206-207</a></span><br /> - -Choquetira Valley, moraine, (ill.), opp. p. <a href="#page_208">208</a><br /> - -Chosica, <a href="#page_136">136</a>, <a href="#page_137">137</a>;<br /> -<span style="margin-left: 1em;">cloudiness (diagr.), <a href="#page_138">138</a></span><br /> - -<i>Chuño</i>, <a href="#page_057">57</a><br /> - -Chuntaguirus, <a href="#page_041">41</a><br /> - -Chuquibamba, <a href="#page_054">54</a>, <a href="#page_072">72</a>, <a href="#page_107">107</a>, <a href="#page_110">110</a>, <a href="#page_111">111</a>, <a href="#page_112">112</a>, <a href="#page_115">115</a>, <a href="#page_116">116</a>, <a href="#page_273">273</a>, <a href="#page_317">317-319</a>;<br /> -<span style="margin-left: 1em;">sediments, <a href="#page_258">258</a></span><br /> - -Chuquibambilla, <a href="#page_053">53</a>, <a href="#page_189">189</a>, <a href="#page_220">220</a>, <a href="#page_221">221</a>, <a href="#page_222">222</a>, <a href="#page_236">236</a>, <a href="#page_243">243</a>;<br /> -<span style="margin-left: 1em;">alluvial fill (diagr.), <a href="#page_272">272</a>;</span><br /> -<span style="margin-left: 1em;">Carboniferous, <a href="#page_244">244</a>;</span><br /> -<span style="margin-left: 1em;">fossils, <a href="#page_323">323</a></span><br /> - -Chuquito pass, crossing (ill.), opp. p. <a href="#page_007">7</a>;<br /> -<span style="margin-left: 1em;">glacial trough (ill.), opp. p. <a href="#page_205">205</a></span><br /> - -Cirque walls, steep (ill.), opp. p. <a href="#page_286">286</a><br /> - -Cirques, <a href="#page_294">294-305</a>;<br /> -<span style="margin-left: 1em;">development (diagr.), <a href="#page_300">300</a>;</span><br /> -<span style="margin-left: 1em;">development, further stages (diagr.), <a href="#page_301">301</a>;</span><br /> -<span style="margin-left: 1em;">mode of formation (diagr.), <a href="#page_297">297</a></span><br /> - -Clarke, J. M., <a href="#page_321">321</a><br /> - -Clearing in forest (ill.), opp. p. <a href="#page_025">25</a><br /> - -Climate, coast, <a href="#page_125">125-147</a>;<br /> -<span style="margin-left: 1em;">eastern border, <a href="#page_147">147-153</a>;</span><br /> -<span style="margin-left: 1em;">Inter-Andean valleys, <a href="#page_153">153-155</a>;</span><br /> -<span style="margin-left: 1em;"><i>see also</i> Meteorological records</span><br /> - -Climatic belts, <a href="#page_121">121-122</a>;<br /> -<span style="margin-left: 1em;">map, <a href="#page_123">123</a></span><br /> - -Climatology, <a href="#page_121">121-156</a><br /> - -Cliza, <a href="#page_276">276</a><br /> - -Cloud-banners, <a href="#page_016">16</a><br /> - -Cloud belt, <a href="#page_143">143</a>, opp. p. <a href="#page_150">150</a> (ill.)<br /> - -Cloudiness, <a href="#page_132">132</a>;<br /> -<span style="margin-left: 1em;">Callao (with diagr.), <a href="#page_133">133</a>;</span><br /> -<span style="margin-left: 1em;">desert station near Caraveli (diagrs.), <a href="#page_137">137</a>;</span><br /> -<span style="margin-left: 1em;">Machu Picchu, <a href="#page_160">160</a>;</span><br /> -<span style="margin-left: 1em;">Santa Lucia (diagr.), <a href="#page_169">169</a></span><br /> - -Clouds, Inter-Andean Valley, <a href="#page_155">155</a>;<br /> -<span style="margin-left: 1em;">Santa Ana (ill.), opp. p. <a href="#page_180">180</a>;</span><br /> -<span style="margin-left: 1em;">Santa Lucia, <a href="#page_168">168</a>;</span><br /> -<span style="margin-left: 1em;">types on eastern border of Andes (diagrs.), <a href="#page_148">148</a>;</span><br /> -<span style="margin-left: 1em;"><i>see also</i> Fog</span><br /> - -Coast Range, <a href="#page_111">111</a>, <a href="#page_113">113</a>, <a href="#page_114">114</a>, <a href="#page_116">116</a>, <a href="#page_118">118</a>, <a href="#page_225">225-232</a>;<br /> -<span style="margin-left: 1em;">climate, <a href="#page_122">122-147</a>;</span><br /> -<span style="margin-left: 1em;">direction, <a href="#page_267">267</a>;</span><br /> -<span style="margin-left: 1em;">diagram to show progressive lowering of saturation temperature in a desert, <a href="#page_127">127</a>;</span><br /> -<span style="margin-left: 1em;">geology, <a href="#page_258">258</a>;</span><br /> -<span style="margin-left: 1em;">view between Mollendo and Arequipa in June (ill.), opp. p. <a href="#page_226">226</a>;</span><br /> -<span style="margin-left: 1em;">wet and dry seasons (diagrs.), <a href="#page_132">132</a></span><br /> - -Coastal belt, map of irrigated and irrigable land, <a href="#page_113">113</a><br /> - -Coastal desert, <a href="#page_110">110-120</a>;<br /> -<span style="margin-left: 1em;">regional diagram of physical relations, <a href="#page_112">112</a>;</span><br /> -<span style="margin-left: 1em;"><i>see also</i> Deserts</span><br /> - -Coastal planter, <a href="#page_006">6</a><br /> - -Coastal region, topographic and climatic provinces (diagr.), <a href="#page_125">125</a><br /> - -Coastal terraces, <a href="#page_225">225-232</a><br /> - -Coca, <a href="#page_074">74</a>, <a href="#page_077">77</a>, <a href="#page_082">82-83</a><br /> - -Coca seed beds (ill.), opp. p. <a href="#page_074">74</a><br /> - -Cochabamba, <a href="#page_093">93</a>;<br /> -<span style="margin-left: 1em;">temperature (diagrs. of ranges), insert opp. p. <a href="#page_178">178</a>;</span><br /> -<span style="margin-left: 1em;">weather data, <a href="#page_176">176-178</a></span><br /> - -Cochabamba Indians, <a href="#page_276">276</a><br /> - -Colombia, <a href="#page_205">205</a><br /> - -Colorada, Pampa de, <a href="#page_114">114</a>, <a href="#page_317">317</a><br /> - -Colpani, <a href="#page_072">72</a>, <a href="#page_215">215</a>, <a href="#page_216">216</a>, <a href="#page_222">222</a>, <a href="#page_223">223</a>;<br /> -<span style="margin-left: 1em;">from ice to sugar cane (ill.), opp. p. <a href="#page_003">3</a></span><br /> - -Comanchian fossils, <a href="#page_323">323</a><br /> - -Cómas, <a href="#page_155">155</a><br /> - -Compañia Gomera de Mainique, <a href="#page_029">29</a>, <a href="#page_031">31</a>, <a href="#page_032">32</a><br /> - -Concession plan, <a href="#page_029">29</a><br /> - -Conibos, <a href="#page_044">44</a><br /> - -<i>Contador</i>, <a href="#page_084">84-85</a><br /> - -Copacavana, <a href="#page_176">176</a><br /> - -Cordilleras, <a href="#page_004">4</a>, <a href="#page_006">6</a>, <a href="#page_020">20</a>, <a href="#page_197">197</a><br /> - -Coribeni, <a href="#page_015">15</a><br /> - -Corn, <a href="#page_057">57</a>, <a href="#page_059">59</a>, <a href="#page_062">62</a><br /> - -Coropuna, <a href="#page_109">109</a>, <a href="#page_110">110</a>, <a href="#page_112">112</a>, <a href="#page_202">202</a>, <a href="#page_253">253</a>, <a href="#page_317">317</a>, <a href="#page_319">319</a>;<br /> -<span style="margin-left: 1em;">elevation, <a href="#page_317">317</a>;</span><br /> -<span style="margin-left: 1em;">glaciation, <a href="#page_307">307</a>;</span><br /> -<span style="margin-left: 1em;">snowline, <a href="#page_283">283-285</a></span><br /> - -Coropuna expedition, <a href="#page_104">104</a><br /> - -Coropuna Quadrangle, <a href="#page_197">197</a>, opp. p. <a href="#page_188">188</a> (topog. sheet), <a href="#page_319">319</a><br /> - -Corralpata, <a href="#page_051">51</a>, <a href="#page_059">59</a><br /> - -Cosos, <a href="#page_231">231</a><br /> - -Cotabambas, <a href="#page_078">78</a><br /> - -Cotahuasi, <a href="#page_004">4</a>, <a href="#page_005">5</a>, <a href="#page_052">52</a>, <a href="#page_054">54</a>, <a href="#page_060">60</a>, <a href="#page_097">97</a>, <a href="#page_101">101</a>, <a href="#page_103">103</a>, <a href="#page_104">104</a>, <a href="#page_180">180</a>, <a href="#page_197">197</a>, <a href="#page_199">199</a>, <a href="#page_316">316</a>, <a href="#page_317">317</a>;<br /> -<span style="margin-left: 1em;">alluvial fill, <a href="#page_272">272</a>;</span><br /> -<span style="margin-left: 1em;">fossils, <a href="#page_322">322</a>;</span><br /> -<span style="margin-left: 1em;">geologic sketch maps and cross-section, <a href="#page_247">247</a>;</span><br /> -<span style="margin-left: 1em;">rug weaver (ill.), opp. p. <a href="#page_068">68</a>;</span><br /> -<span style="margin-left: 1em;">snowline above, <a href="#page_282">282-283</a>;</span><br /> -<span style="margin-left: 1em;">temperature curve (diagr.), <a href="#page_180">180</a>;</span><br /> -<span style="margin-left: 1em;">view (ill.), opp. p. <a href="#page_057">57</a></span><br /> - -Cotahuasi Canyon, <a href="#page_247">247</a>, <a href="#page_248">248</a>, <a href="#page_316">316</a><br /> - -Cotahuasi Quadrangle (topog. sheet), opp. p. <a href="#page_192">192</a><br /> - -Cotahuasi Valley, geology, <a href="#page_258">258</a><br /> - -Cotton, <a href="#page_076">76</a>, <a href="#page_116">116</a>, <a href="#page_117">117</a><br /> - -Crest lines, asymmetrical, <a href="#page_305">305-313</a><br /> - -Cretaceous formations, <a href="#page_247">247-251</a><br /> - -Cretaceous fossils, <a href="#page_323">323</a><br /> - -Crucero Alto, <a href="#page_188">188</a><br /> - -Cuzco, <a href="#page_008">8</a>, <a href="#page_010">10</a>, <a href="#page_021">21</a>, <a href="#page_052">52</a>, <a href="#page_062">62</a>, <a href="#page_063">63</a>, <a href="#page_092">92</a>, <a href="#page_102">102</a>, <a href="#page_107">107</a>, <a href="#page_193">193</a>, <a href="#page_197">197</a>;<br /> -<span style="margin-left: 1em;">railroad to Santa Ana, <a href="#page_069">69-70</a>;</span><br /> -<span style="margin-left: 1em;">snow, <a href="#page_276">276</a>;</span><br /> -<span style="margin-left: 1em;">view (ill.), opp. p. <a href="#page_066">66</a></span><br /> - -Cuzco basin, <a href="#page_061">61</a>, <a href="#page_062">62</a>, <a href="#page_154">154</a>, <a href="#page_251">251</a>;<br /> -<span style="margin-left: 1em;">slopes at outlet (diagr.), <a href="#page_185">185</a></span><br /> - -<br /> -<a name="D-2" id="D-2"></a>Deformations. <i>See</i> Intrusions<br /> - -Derby, Orville, <a href="#page_322">322</a><br /> - -Desaguadero Valley, <a href="#page_193">193</a><br /> - -Deserts, cloudiness (diagrs.), <a href="#page_137">137</a>;<br /> -<span style="margin-left: 1em;">rain, <a href="#page_138">138-140</a>;</span><br /> -<span style="margin-left: 1em;">sea-breeze in, <a href="#page_132">132</a>;</span><br /> -<span style="margin-left: 1em;">tropical forest, <a href="#page_036">36-37</a>;</span><br /> -<span style="margin-left: 1em;">wind roses (diagrs.), <a href="#page_136">136</a></span><br /> - -Diagrams. <i>See</i> Regional diagrams<br /> - -Dikes, <a href="#page_223">223</a><br /> - -Drunkenness, <a href="#page_103">103</a>, <a href="#page_105">105-106</a>, <a href="#page_108">108</a><br /> - -Dry valleys, <a href="#page_114">114-115</a><br /> - -Dunes, <a href="#page_114">114</a>, <a href="#page_254">254</a>;<br /> -<span style="margin-left: 1em;">Majes Valley, <a href="#page_262">262-267</a>;</span><br /> -<span style="margin-left: 1em;">movement, <a href="#page_132">132</a>;</span><br /> -<span style="margin-left: 1em;">superimposed (diagrs.), <a href="#page_265">265</a></span><br /> - -Duque, Señor, <a href="#page_078">78</a><br /> - -<br /> -<a name="E-2" id="E-2"></a>Eastern Andes, <a href="#page_204">204-224</a>;<br /> -<span style="margin-left: 1em;">regional diagram, <a href="#page_022">22</a></span><br /> - -Eastern border, climate, <a href="#page_147">147-153</a><br /> - -Eastern valley planter, <a href="#page_003">3</a><br /> - -Eastern valleys, <a href="#page_068">68-87</a>;<br /> -<span style="margin-left: 1em;">climate cross-section (diagr.), <a href="#page_079">79</a></span><br /> - -Echarati, <a href="#page_010">10</a>, <a href="#page_077">77</a>, <a href="#page_078">78</a>, <a href="#page_080">80</a>, <a href="#page_082">82</a>;<br /> -<span style="margin-left: 1em;">plantation scene (ill.), opp. p. <a href="#page_075">75</a></span><br /> - -Ecuador volcanoes, <a href="#page_281">281</a><br /> - -Epiphyte (ill.), opp. p. <a href="#page_078">78</a><br /> - -Erdis, E. C., <a href="#page_158">158</a><br /> - -Erosion, <a href="#page_192">192-195</a>, <a href="#page_210">210</a>, <a href="#page_211">211</a>, <a href="#page_305">305</a>;<br /> -<span style="margin-left: 1em;"><i>see also</i> Glacial erosion; Nivation</span><br /> - -Erving, Dr. W. G., <a href="#page_013">13</a>, <a href="#page_101">101</a>, <a href="#page_316">316</a>, <a href="#page_317">317</a><br /> - -<br /> -<i><a name="F-2" id="F-2"></a>Faena</i> Indians, <a href="#page_075">75</a>, <a href="#page_083">83-87</a><br /> - -Feasts and fairs, <a href="#page_175">175-176</a><br /> - -Ferries, <a href="#page_147">147</a><br /> - -Fig tree (ill.), opp. p. <a href="#page_075">75</a><br /> - -Floods, <a href="#page_151">151</a><br /> - -Fog, <a href="#page_132">132</a>, <a href="#page_139">139</a>, <a href="#page_143">143</a>;<br /> -<span style="margin-left: 1em;">conditions along coast from Camaná to Mollendo, <a href="#page_144">144-145</a>;</span><br /> -<span style="margin-left: 1em;"><i>see also</i> Clouds</span><br /> - -Forest dweller, <a href="#page_001">1</a><br /> - -Forest Indians. <i>See</i> Machigangas<br /> - -Forests, clearing (ill.), opp. p. <a href="#page_025">25</a>;<br /> -<span style="margin-left: 1em;">dense ground cover, trees, epiphytes, and parasites (ill.), opp. p. <a href="#page_155">155</a>;</span><br /> -<span style="margin-left: 1em;">moss-draped trees (ill.), opp. p. <a href="#page_024">24</a>;</span><br /> -<span style="margin-left: 1em;">mountain, <a href="#page_148">148-153</a>;</span><br /> -<span style="margin-left: 1em;">mule trail (ill.), opp. p. <a href="#page_018">18</a>;</span><br /> -<span style="margin-left: 1em;">tropical, near Pabellon (ill.), opp. p. <a href="#page_150">150</a>;</span><br /> -<span style="margin-left: 1em;">tropical vegetation (ill.), opp. p. <a href="#page_018">18</a>;</span><br /> -<span style="margin-left: 1em;">type at Sahuayaco (ill.), opp. p. <a href="#page_090">90</a></span><br /> - -Fossils, <a href="#page_245">245</a>, <a href="#page_321">321</a>;<br /> -<span style="margin-left: 1em;">list of, by geologic periods and localities, <a href="#page_321">321</a></span><br /> - -Frankland, <a href="#page_278">278</a>, <a href="#page_309">309</a><br /> - -Frost line, <a href="#page_056">56-57</a><br /> - -<br /> -<a name="G-2" id="G-2"></a>Garua, <a href="#page_132">132</a><br /> - -Geographical basis of revolutions and of human character, <a href="#page_088">88-109</a><br /> - -Geologic dates, <a href="#page_195">195-196</a>;<br /> -<span style="margin-left: 1em;">Majes Valley, <a href="#page_258">258</a>, <a href="#page_261">261</a>;</span><br /> -<span style="margin-left: 1em;">west coast fault, <a href="#page_248">248-249</a></span><br /> - -Geologic development. <i>See</i> Physiographic and geologic development<br /> - -Gilbert, G. K., <a href="#page_300">300</a>, <a href="#page_302">302</a>, <a href="#page_305">305</a><br /> - -Glacial deposits, <a href="#page_268">268</a><br /> - -Glacial erosion, Central Andes, <a href="#page_305">305-313</a>;<br /> -<span style="margin-left: 1em;">composite sketch of general conditions, <a href="#page_312">312</a>;</span><br /> -<span style="margin-left: 1em;">graphic representation of amount during glacial period, <a href="#page_311">311</a></span><br /> - -Glacial features, <a href="#page_274">274-313</a>;<br /> -<span style="margin-left: 1em;">Arequipa (sketches), <a href="#page_280">280</a>;</span><br /> -<span style="margin-left: 1em;">Central Ranges; lateral moraines (ill.), opp. p. <a href="#page_269">269</a>;</span><br /> -<span style="margin-left: 1em;">eastern slopes of Cordillera Vilcapampa (map), <a href="#page_210">210</a></span><br /> - -Glacial retreat, <a href="#page_208">208-214</a><br /> - -Glacial sculpture, heart of the Cordillera Vilcapampa (map), <a href="#page_212">212</a>;<br /> -<span style="margin-left: 1em;">southwestern flank of Cordillera Vilcapampa (map), <a href="#page_207">207</a></span><br /> - -Glacial topography between Lambrama and Antabamba (ill.), opp. p. <a href="#page_280">280</a>;<br /> -<span style="margin-left: 1em;">Maritime Cordillera, north of divide on 73d meridian (ill.), opp. p. <a href="#page_281">281</a></span><br /> - -Glacial trough, view near Chuquito pass (ill.), opp. p. <a href="#page_208">208</a><br /> - -Glaciation, <a href="#page_064">64</a>, <a href="#page_271">271</a>;<br /> -<span style="margin-left: 1em;">Sierra Nevada, <a href="#page_305">305</a>;</span><br /> -<span style="margin-left: 1em;">Vilcapampa, <a href="#page_204">204-214</a>;</span><br /> -<span style="margin-left: 1em;">Western Andes, <a href="#page_202">202</a></span><br /> - -Glaciers, Panta Mountain (ill.), opp. p. <a href="#page_287">287</a>;<br /> -<span style="margin-left: 1em;">view (ill.), opp. p. <a href="#page_205">205</a></span><br /> - -Gomara, <a href="#page_034">34</a><br /> - -Gonzales, Señor, <a href="#page_078">78</a><br /> - -Government, bad, <a href="#page_095">95</a><br /> - -Gran Pajonal, <a href="#page_037">37</a><br /> - -Granite, <a href="#page_215">215-224</a>;<br /> -<span style="margin-left: 1em;"><i>see also</i> Intrusions</span><br /> - -Grass (ill.), opp. p. <a href="#page_154">154</a><br /> - -Gregory, J. W., <a href="#page_205">205</a><br /> - -<br /> -<i><a name="H-2" id="H-2"></a>Hacendado</i>, <a href="#page_055">55</a>, <a href="#page_060">60</a><br /> - -<i>Haciendas</i>, <a href="#page_078">78</a>, <a href="#page_083">83</a>, <a href="#page_086">86</a><br /> - -Hann, J., <a href="#page_126">126</a>, <a href="#page_176">176</a>, <a href="#page_278">278</a><br /> - -Hendriksen, Kai, <a href="#page_098">98</a>, <a href="#page_315">315</a><br /> - -Hettner, <a href="#page_205">205</a><br /> - -Hevea, <a href="#page_029">29</a><br /> - -Highest habitations in the world, <a href="#page_052">52</a>, <a href="#page_096">96</a>;<br /> -<span style="margin-left: 1em;">regional diagram of, <a href="#page_050">50</a>;</span><br /> -<span style="margin-left: 1em;">stone hut (ill.), opp. p. <a href="#page_048">48</a></span><br /> - -Highland shepherd, <a href="#page_004">4</a><br /> - -Highlands, <a href="#page_046">46</a><br /> - -Hobbs, W. H., <a href="#page_286">286</a>, <a href="#page_287">287</a><br /> - -Horses, <a href="#page_066">66</a>, opp. p. <a href="#page_091">91</a> (ill.)<br /> - -Huadquiña, <a href="#page_070">70</a>, <a href="#page_071">71</a>, <a href="#page_072">72</a>, <a href="#page_075">75</a>, <a href="#page_082">82</a>, <a href="#page_086">86</a>, <a href="#page_219">219</a>;<br /> -<span style="margin-left: 1em;">hacienda (ill.), opp. p. <a href="#page_073">73</a>;</span><br /> -<span style="margin-left: 1em;">terraces, <a href="#page_272">272</a></span><br /> - -Huadquirca, <a href="#page_243">243</a><br /> - -Huaipo, Lake, <a href="#page_250">250</a>, <a href="#page_251">251</a><br /> - -Huallaga basin, <a href="#page_153">153</a><br /> - -Huambo, <a href="#page_243">243</a><br /> - -Huancarama, <a href="#page_064">64</a>, <a href="#page_087">87</a>, <a href="#page_189">189</a>, <a href="#page_243">243</a>, <a href="#page_303">303</a>;<br /> -<span style="margin-left: 1em;">view (ill.), opp. p. <a href="#page_106">106</a></span><br /> - -Huancarqui, <a href="#page_257">257</a><br /> - -Huari, <a href="#page_176">176</a><br /> - -Huascatay, <a href="#page_189">189</a>, <a href="#page_242">242</a>, <a href="#page_243">243</a>;<br /> -<span style="margin-left: 1em;">Carboniferous, <a href="#page_244">244</a>;</span><br /> -<span style="margin-left: 1em;">fossils, <a href="#page_322">322</a></span><br /> - -Huasco basin, <a href="#page_275">275</a><br /> - -Huaynacotas, <a href="#page_103">103</a>, <a href="#page_316">316</a>;<br /> -<span style="margin-left: 1em;">terraced valley slope (ill.), opp. p. <a href="#page_056">56</a>;</span><br /> -<span style="margin-left: 1em;">terraced valley slopes (ill.), opp. p. <a href="#page_199">199</a></span><br /> - -Huichihua, <a href="#page_278">278</a>; alluvial fill (diagr.), <a href="#page_272">272</a>;<br /> -<span style="margin-left: 1em;">(ill.), opp. p. <a href="#page_067">67</a></span><br /> - -Human character, geographic basis, <a href="#page_088">88-109</a><br /> - -Humboldt, <a href="#page_033">33-35</a>, <a href="#page_286">286</a><br /> - -Humboldt Current, <a href="#page_126">126</a>, <a href="#page_143">143</a><br /> - -Huts, <a href="#page_103">103</a>;<br /> -<span style="margin-left: 1em;">highest in Peru (ill.), opp. p. <a href="#page_048">48</a>;</span><br /> -<span style="margin-left: 1em;">shepherds’, <a href="#page_047">47</a>, <a href="#page_048">48</a>, <a href="#page_052">52</a>, <a href="#page_055">55</a></span><br /> - -<br /> -<a name="I-2" id="I-2"></a>Ica Valley, <a href="#page_120">120</a>;<br /> -<span style="margin-left: 1em;">irrigated and irrigable land (diagr.), <a href="#page_118">118</a></span><br /> - -Ice erosion. <i>See</i> Glacial erosion<br /> - -Incahuasi, <a href="#page_051">51</a>, <a href="#page_155">155</a>, <a href="#page_285">285</a><br /> - -Incas, <a href="#page_039">39</a>, <a href="#page_044">44</a>, <a href="#page_046">46</a>, <a href="#page_062">62</a>, <a href="#page_063">63</a>, <a href="#page_068">68</a>, <a href="#page_077">77</a>, <a href="#page_109">109</a>, <a href="#page_175">175</a><br /> - -Incharate, <a href="#page_078">78</a><br /> - -Indian boatmen, <a href="#page_013">13</a><br /> - -Indians, as laborers, <a href="#page_026">26-28</a>, <a href="#page_031">31-32</a>;<br /> -<span style="margin-left: 1em;">basin type, <a href="#page_063">63-64</a>;</span><br /> -<span style="margin-left: 1em;">forest, <i>see</i> Machigangas;</span><br /> -<span style="margin-left: 1em;">life and tastes, <a href="#page_107">107-108</a>;</span><br /> -<span style="margin-left: 1em;">mountain, <a href="#page_046">46-67</a>, <a href="#page_101">101-102</a>;</span><br /> -<span style="margin-left: 1em;">plateau, <a href="#page_040">40-41</a>, <a href="#page_044">44-45</a>, <a href="#page_100">100</a>, <a href="#page_106">106-109</a>;</span><br /> -<span style="margin-left: 1em;">troops, <a href="#page_090">90</a>, <a href="#page_091">91</a>;</span><br /> -<span style="margin-left: 1em;">wrongs, <a href="#page_014">14</a>, <a href="#page_102">102</a></span><br /> - -Ingomwimbi, <a href="#page_206">206</a><br /> - -Instruments, surveying, <a href="#page_315">315</a><br /> - -Inter-Andean valleys, climate, <a href="#page_153">153-155</a><br /> - -Intermont basin. <i>See</i> Basins<br /> - -Intrusions, deformations north of Lambrama (diagr.), <a href="#page_243">243</a>;<br /> -<span style="margin-left: 1em;">deformative effects on limestone strata near Chuquibambilla (diagr.), <a href="#page_221">221</a>;</span><br /> -<span style="margin-left: 1em;">lower Urubamba Valley (geologic sketch map), <a href="#page_237">237</a>;</span><br /> -<span style="margin-left: 1em;">overthrust folds in detail near Chuquibambilla (diagr.), <a href="#page_222">222</a>;</span><br /> -<span style="margin-left: 1em;">principles, <a href="#page_217">217-219</a></span><br /> - -Intrusions, Vilcapampa, deformative effects near Puquiura (diagr.), <a href="#page_216">216</a>;<br /> -<span style="margin-left: 1em;">relation of granite to schist near Colpani (with diagr.), <a href="#page_216">216</a></span><br /> - -Iquique, wind roses (diagrs.), <a href="#page_131">131</a><br /> - -Irrigation, <a href="#page_072">72</a>, <a href="#page_076">76</a>, <a href="#page_080">80</a>, <a href="#page_082">82</a>;<br /> -<span style="margin-left: 1em;">coastal belt (map), <a href="#page_113">113</a>;</span><br /> -<span style="margin-left: 1em;">coastal desert, <a href="#page_119">119-120</a>;</span><br /> -<span style="margin-left: 1em;">Ica Valley (diagr.), <a href="#page_118">118</a></span><br /> - -Islay, Pampa de, <a href="#page_114">114</a><br /> - -Italians, <a href="#page_018">18</a>, <a href="#page_081">81</a><br /> - -<br /> -<a name="J-2" id="J-2"></a>Jaguey, <a href="#page_254">254</a>, <a href="#page_255">255</a>, <a href="#page_318">318</a><br /> - -Jesuits, <a href="#page_068">68</a><br /> - -Johnson, W. D., <a href="#page_213">213</a>, <a href="#page_295">295</a>, <a href="#page_296">296</a>, <a href="#page_299">299</a>, <a href="#page_300">300</a><br /> - -<br /> -<a name="K-2" id="K-2"></a>Kenia, Mt., <a href="#page_206">206</a>, <a href="#page_274">274</a><br /> - -Kerbey, Major, <a href="#page_008">8</a>, <a href="#page_010">10</a><br /> - -Kibo, <a href="#page_206">206</a>, <a href="#page_274">274</a><br /> - -Kilimandjaro, <a href="#page_205">205</a>, <a href="#page_206">206</a><br /> - -Kinibalu, <a href="#page_206">206</a><br /> - -Krüger, Herr, <a href="#page_157">157</a><br /> - -<br /> -<a name="L-2" id="L-2"></a>Labor, <a href="#page_026">26-28</a>, <a href="#page_031">31-32</a>, <a href="#page_042">42-43</a>, <a href="#page_074">74-75</a>, <a href="#page_083">83-84</a><br /> - -La Cumbre Quadrangle, <a href="#page_197">197</a>, <a href="#page_202">202</a>, opp. p. <a href="#page_202">202</a> (topog. sheet)<br /> - -La Joya, <a href="#page_132">132</a>, <a href="#page_133">133</a>;<br /> -<span style="margin-left: 1em;">cloudiness (diagr.), <a href="#page_134">134</a>;</span><br /> -<span style="margin-left: 1em;">temperature curves (diagr.), <a href="#page_134">134</a>;</span><br /> -<span style="margin-left: 1em;">wind roses (diagrs.), <a href="#page_135">135</a></span><br /> - -Lambrama, <a href="#page_090">90</a>, <a href="#page_092">92</a>, <a href="#page_285">285</a>, <a href="#page_316">316</a>;<br /> -<span style="margin-left: 1em;">camp near (ill.), opp. p. <a href="#page_006">6</a></span><br /> - -Lambrama Quadrangle (topog. sheet), opp. p. <a href="#page_304">304</a><br /> - -Lambrama Valley, deformation types (diagr.), <a href="#page_243">243</a><br /> - -Land and sea, Carboniferous hypothetical distribution compared with present (diagr.), <a href="#page_246">246</a><br /> - -Landscape, <a href="#page_183">183-198</a><br /> - -Lanius, P. B., <a href="#page_013">13</a><br /> - -La Paz, <a href="#page_093">93</a>, <a href="#page_109">109</a>, <a href="#page_276">276</a>, <a href="#page_321">321</a><br /> - -La Sama, <a href="#page_012">12</a>, <a href="#page_013">13</a>, <a href="#page_040">40</a><br /> - -Las Lomas, <a href="#page_318">318</a><br /> - -Lava flows, <a href="#page_199">199</a><br /> - -Lava plateau, <a href="#page_197">197</a>, <a href="#page_199">199</a>, <a href="#page_307">307-308</a>;<br /> -<span style="margin-left: 1em;">regional diagram of physical conditions, <a href="#page_055">55</a>;</span><br /> -<span style="margin-left: 1em;">summit above Cotahuasi (ill.), opp. p. <a href="#page_204">204</a></span><br /> - -Lavas, volume, <a href="#page_201">201</a><br /> - -Lima, <a href="#page_092">92</a>, <a href="#page_093">93</a>, <a href="#page_118">118</a>, <a href="#page_137">137</a>, <a href="#page_138">138</a>;<br /> -<span style="margin-left: 1em;">cloud, <a href="#page_132">132</a>, <a href="#page_143">143</a>;</span><br /> -<span style="margin-left: 1em;">temperature, <a href="#page_126">126</a></span><br /> - -Limestone, sketch to show deformed, <a href="#page_243">243</a><br /> - -Little, J. P., <a href="#page_135">135</a>, <a href="#page_157">157</a><br /> - -Llica, <a href="#page_275">275</a><br /> - -Lower Cretaceous fossils, <a href="#page_323">323</a><br /> - -Lower Devonian fossils, <a href="#page_321">321</a><br /> - -<br /> -<a name="M-2" id="M-2"></a>Machigangas, <a href="#page_010">10</a>, <a href="#page_011">11</a>, <a href="#page_012">12</a>, <a href="#page_014">14</a>, <a href="#page_018">18</a>, <a href="#page_019">19</a>, <a href="#page_031">31</a>, <a href="#page_036">36-45</a>, <a href="#page_081">81</a>;<br /> -<span style="margin-left: 1em;">ornaments and fabrics (ill.), opp. p. <a href="#page_027">27</a>;</span><br /> -<span style="margin-left: 1em;">trading with (ill.), opp. p. <a href="#page_026">26</a></span><br /> - -Machu Picchu, <a href="#page_072">72</a>, <a href="#page_220">220</a>;<br /> -<span style="margin-left: 1em;">weather data (with diagr.), <a href="#page_158">158-160</a></span><br /> - -Madeira-Mamoré railroad, <a href="#page_033">33</a><br /> - -Madre de Dios, <a href="#page_001">1</a>, <a href="#page_002">2</a>, <a href="#page_033">33</a><br /> - -Majes River, <a href="#page_147">147</a>, <a href="#page_225">225</a>, <a href="#page_227">227</a>, <a href="#page_266">266</a>, <a href="#page_267">267</a>;<br /> -<span style="margin-left: 1em;">Canyon (ill.), opp. p. <a href="#page_230">230</a></span><br /> - -Majes Valley, <a href="#page_106">106</a>, <a href="#page_111">111</a>, <a href="#page_116">116</a>, <a href="#page_117">117</a>, <a href="#page_120">120</a>, <a href="#page_226">226</a>, <a href="#page_227">227</a>, <a href="#page_229">229-231</a>, <a href="#page_318">318</a>;<br /> -<span style="margin-left: 1em;">alluvial fill, <a href="#page_273">273</a>;</span><br /> -<span style="margin-left: 1em;">date of formation, <a href="#page_258">258</a>, <a href="#page_261">261</a>;</span><br /> -<span style="margin-left: 1em;">desert coast (ill.), opp. p. <a href="#page_110">110</a>;</span><br /> -<span style="margin-left: 1em;">dunes, <a href="#page_262">262-267</a>;</span><br /> -<span style="margin-left: 1em;">erosion and uplift, <a href="#page_261">261</a>;</span><br /> -<span style="margin-left: 1em;">lower and upper sandstones (ill.), opp. p. <a href="#page_250">250</a>;</span><br /> -<span style="margin-left: 1em;">sediments, <a href="#page_255">255</a>;</span><br /> -<span style="margin-left: 1em;">snowline, <a href="#page_283">283</a>;</span><br /> -<span style="margin-left: 1em;">steep walls and alluvial fill (ill.), opp. p. <a href="#page_230">230</a>;</span><br /> -<span style="margin-left: 1em;">structural details near Aplao (sketch section), <a href="#page_255">255</a>;</span><br /> -<span style="margin-left: 1em;">structural details on south wall near Cantas (sketch section), <a href="#page_257">257</a>;</span><br /> -<span style="margin-left: 1em;">structural relations at Aplao (field sketch), <a href="#page_256">256</a>;</span><br /> -<span style="margin-left: 1em;">Tertiary deposits, <a href="#page_253">253-254</a>;</span><br /> -<span style="margin-left: 1em;">wind, <a href="#page_130">130</a>;</span><br /> -<span style="margin-left: 1em;">view below Cantas (ill.), opp. p. <a href="#page_110">110</a>;</span><br /> -<span style="margin-left: 1em;">view down canyon (ill.), opp. p. <a href="#page_144">144</a></span><br /> - -Malaria, <a href="#page_014">14</a>, <a href="#page_038">38</a><br /> - -Marañon, <a href="#page_041">41</a>, <a href="#page_059">59</a><br /> - -Marcoy, <a href="#page_079">79</a><br /> - -Marine terrace at Mollendo (ill.), opp. p. <a href="#page_226">226</a><br /> - -Maritime Cordillera, <a href="#page_052">52</a>, <a href="#page_199">199-203</a>, <a href="#page_233">233</a>;<br /> -<span style="margin-left: 1em;">asymmetry of ridges, <a href="#page_308">308-309</a>;</span><br /> -<span style="margin-left: 1em;">glacial features, <a href="#page_307">307</a>;</span><br /> -<span style="margin-left: 1em;">glacial topography north of divide on 73d meridian (ill.), opp. p. <a href="#page_281">281</a>;</span><br /> -<span style="margin-left: 1em;">pre-volcanic topography, <a href="#page_200">200</a>;</span><br /> -<span style="margin-left: 1em;">post-glacial volcano, asymmetrical (diagr.), <a href="#page_306">306</a>;</span><br /> -<span style="margin-left: 1em;">regional diagrams, <a href="#page_050">50</a>, <a href="#page_052">52</a>;</span><br /> -<span style="margin-left: 1em;">test of explanation of cirques, <a href="#page_303">303</a>;</span><br /> -<span style="margin-left: 1em;">volcanoes, tuffs, lava flows (ill.), opp. p. <a href="#page_204">204</a>;</span><br /> -<span style="margin-left: 1em;">western border rocks (geologic section), <a href="#page_257">257</a>;</span><br /> -<span style="margin-left: 1em;"><i>see also</i> Lava plateau</span><br /> - -Matara, <a href="#page_099">99</a>, <a href="#page_316">316</a><br /> - -Matthes, F. E., <a href="#page_286">286</a>, <a href="#page_287">287</a>, <a href="#page_289">289</a><br /> - -Mature slopes, <a href="#page_185">185-193</a>; between Ollantaytambo and Urubamba (ill.), opp. p. <a href="#page_185">185</a>;<br /> -<span style="margin-left: 1em;">dissected, north of Anta (ill.), opp. p. <a href="#page_185">185</a></span><br /> - -Mawenzi, <a href="#page_206">206</a><br /> - -Meanders, <a href="#page_016">16</a>, <a href="#page_017">17</a><br /> - -Médanos, <a href="#page_114">114</a><br /> - -Mendoza, Padre, <a href="#page_011">11</a><br /> - -Mer de Glace, <a href="#page_203">203</a><br /> - -Meteorological records, <a href="#page_157">157-181</a><br /> - -Mexican revolutions, <a href="#page_093">93</a><br /> - -Middendorf, <a href="#page_143">143</a><br /> - -Miller, General, <a href="#page_041">41</a>, <a href="#page_078">78</a>, <a href="#page_147">147</a><br /> - -Minchin, <a href="#page_241">241</a><br /> - -Misti, El, opp. p. <a href="#page_007">7</a> (ill.), <a href="#page_284">284</a><br /> - -Molina, Christoval de, <a href="#page_175">175</a><br /> - -Mollendo, <a href="#page_093">93</a>, <a href="#page_105">105</a>, <a href="#page_117">117</a>;<br /> -<span style="margin-left: 1em;">cloud belt, <a href="#page_143">143</a>;</span><br /> -<span style="margin-left: 1em;">cloudiness (diagr.), <a href="#page_134">134</a>;</span><br /> -<span style="margin-left: 1em;">coastal terraces, <a href="#page_225">225</a>;</span><br /> -<span style="margin-left: 1em;">humidity, <a href="#page_133">133</a>;</span><br /> -<span style="margin-left: 1em;">marine terrace (ill.), opp. p. <a href="#page_226">226</a>;</span><br /> -<span style="margin-left: 1em;">profile of coastal terraces (diagr.), <a href="#page_227">227</a>;</span><br /> -<span style="margin-left: 1em;">temperature curves (diagr.), <a href="#page_134">134</a>;</span><br /> -<span style="margin-left: 1em;">wind roses (diagrs.), <a href="#page_129">129</a></span><br /> - -Mollendo-Arequipa railroad, <a href="#page_117">117</a><br /> - -Mollendo rubber, <a href="#page_032">32</a><br /> - -Montaña, <a href="#page_148">148</a>, <a href="#page_149">149</a>, <a href="#page_153">153</a><br /> - -Moquegua, <a href="#page_117">117</a>;<br /> -<span style="margin-left: 1em;">geologic relations (diagr.), <a href="#page_255">255</a></span><br /> - -Moraines, <a href="#page_207">207</a>, <a href="#page_210">210-211</a>;<br /> -<span style="margin-left: 1em;">Choquetira Valley (ill.), opp. p. <a href="#page_208">208</a>;</span><br /> -<span style="margin-left: 1em;">view (ill.), opp. p. <a href="#page_208">208</a></span><br /> - -Morales, Señor, <a href="#page_011">11</a><br /> - -Morococha, temperature (diagrs. of ranges), insert opp. p. <a href="#page_172">172</a>;<br /> -<span style="margin-left: 1em;">weather data (with diagrs.), <a href="#page_171">171-176</a></span><br /> - -Morococha Mining Co., <a href="#page_157">157</a>, <a href="#page_171">171</a><br /> - -Morro de Arica, <a href="#page_132">132</a><br /> - -Moss, large ground. <i>See Yareta</i><br /> - -Moss-draped trees (ill.), opp. p. <a href="#page_024">24</a><br /> - -Mountain-side trail (ill.), opp. p. <a href="#page_078">78</a><br /> - -Mountains, tropical, as climate registers, <a href="#page_206">206</a><br /> - -Mulanquiato, <a href="#page_010">10</a>, <a href="#page_018">18</a>, <a href="#page_019">19</a><br /> - -Mule trail (ill.), opp. p. <a href="#page_018">18</a><br /> - -Mules, <a href="#page_023">23</a>, <a href="#page_024">24</a>, <a href="#page_094">94</a>, opp. p. <a href="#page_091">91</a> (ill.)<br /> - -<br /> -<a name="N-2" id="N-2"></a>Névé, <a href="#page_286">286-305</a><br /> - -Niño, El, <a href="#page_137">137-138</a><br /> - -Nivation, <a href="#page_285">285-294</a>;<br /> -<span style="margin-left: 1em;">“pocked†surface (ill.), opp. p. <a href="#page_286">286</a></span><br /> - -Northeastern border, topographic and structural section (diagr.), <a href="#page_241">241</a><br /> - -<br /> -<a name="O-2" id="O-2"></a>Occobamba Valley, <a href="#page_079">79</a><br /> - -Ocean currents of adjacent waters, <a href="#page_121">121-122</a> (map), <a href="#page_123">123</a><br /> - -Ollantaytambo, <a href="#page_070">70</a>, <a href="#page_073">73</a>, <a href="#page_075">75</a>, <a href="#page_250">250</a>, <a href="#page_271">271</a>;<br /> -<span style="margin-left: 1em;">terraced valley floor (ill.), opp. p. <a href="#page_056">56</a></span><br /> - -d’Orbigny, <a href="#page_322">322</a><br /> - -Oruro, <a href="#page_093">93</a><br /> - -<br /> -<a name="P-2" id="P-2"></a>Pabellon, <a href="#page_080">80</a>, <a href="#page_082">82</a>, opp. p. <a href="#page_150">150</a><br /> - -Pacasmayo, Carboniferous land plants, <a href="#page_245">245</a><br /> - -Pachitea, <a href="#page_037">37</a>, <a href="#page_038">38</a><br /> - -Pacific Ocean basin, <a href="#page_248">248</a><br /> - -Paleozoic strata (ill.), opp. p. <a href="#page_198">198</a><br /> - -<i>Palma carmona</i>, <a href="#page_029">29</a><br /> - -Palmer, H. S., <a href="#page_250">250</a><br /> - -Paltaybamba, opp. p. <a href="#page_074">74</a><br /> - -Pampacolca, <a href="#page_109">109</a><br /> - -Pampaconas, <a href="#page_069">69</a>, <a href="#page_211">211</a>, <a href="#page_213">213</a>, <a href="#page_215">215</a>;<br /> -<span style="margin-left: 1em;">rounded slopes near Vilcabamba (ill.), opp. p. <a href="#page_072">72</a>;</span><br /> -<span style="margin-left: 1em;">Carboniferous, <a href="#page_244">244</a>;</span><br /> -<span style="margin-left: 1em;">fossils, <a href="#page_322">322</a>;</span><br /> -<span style="margin-left: 1em;">snow action, <a href="#page_291">291</a></span><br /> - -Pampaconas River, <a href="#page_316">316</a><br /> - -Pampas, <a href="#page_114">114</a>, <a href="#page_198">198</a>;<br /> -<span style="margin-left: 1em;">climate data, <a href="#page_134">134-136</a></span><br /> - -Pampas, river, <a href="#page_189">189</a><br /> - -Panta, mt., <a href="#page_214">214</a>;<br /> -<span style="margin-left: 1em;">view, with glacier system (ill.), opp. p. <a href="#page_287">287</a></span><br /> - -Pará rubber, <a href="#page_032">32</a><br /> - -Pasaje, <a href="#page_051">51</a>, <a href="#page_057">57</a>, <a href="#page_059">59</a>, <a href="#page_060">60</a>, <a href="#page_236">236</a>, <a href="#page_238">238</a>, <a href="#page_240">240</a>, <a href="#page_241">241</a>, <a href="#page_243">243</a>;<br /> -<span style="margin-left: 1em;">Carboniferous, <a href="#page_244">244</a>;</span><br /> -<span style="margin-left: 1em;">crossing the Apurimac (ills.), opp. p. <a href="#page_091">91</a></span><br /> - -Paschinger, <a href="#page_274">274</a><br /> - -Pastures, <a href="#page_141">141</a>, <a href="#page_187">187</a>;<br /> -<span style="margin-left: 1em;">Alpine (ill.), opp. p. <a href="#page_058">58</a></span><br /> - -Paucartambo, <a href="#page_042">42</a>, <a href="#page_077">77</a><br /> - -Paucartambo River. <i>See</i> Yavero River<br /> - -Payta, <a href="#page_225">225</a><br /> - -Penck, A., <a href="#page_205">205</a><br /> - -Peonage, <a href="#page_025">25</a>, <a href="#page_027">27</a>, <a href="#page_028">28</a><br /> - -Pereira, Señor, <a href="#page_010">10</a>, <a href="#page_018">18</a><br /> - -Perene, <a href="#page_155">155</a><br /> - -Physiographic and geologic development, <a href="#page_233">233-273</a><br /> - -Physiographic evidence, value, <a href="#page_193">193-195</a><br /> - -Physiographic principles, <a href="#page_217">217</a><br /> - -Physiography, <a href="#page_183">183-186</a>;<br /> -<span style="margin-left: 1em;">Southern Peru, summary, <a href="#page_197">197-198</a></span><br /> - -Pichu-Pichu, <a href="#page_284">284</a><br /> - -Piedmont accumulations, <a href="#page_260">260</a><br /> - -Pilcopata, <a href="#page_036">36</a><br /> - -Piñi-piñi, <a href="#page_036">36</a><br /> - -Pisco, <a href="#page_130">130</a>;<br /> -<span style="margin-left: 1em;">Carboniferous land plants, <a href="#page_247">247</a></span><br /> - -Piura, <a href="#page_119">119</a><br /> - -Piura River, depth diagram, <a href="#page_119">119</a>, <a href="#page_120">120</a><br /> - -Piura Valley, <a href="#page_048">48</a><br /> - -Place names, key to, <a href="#page_324">324</a><br /> - -Plantations, <a href="#page_086">86</a>;<br /> -<span style="margin-left: 1em;"><i>see also</i> Haciendas</span><br /> - -Planter, coastal, <a href="#page_006">6</a><br /> - -Planters, valley, <a href="#page_003">3</a>, <a href="#page_075">75</a>, <a href="#page_076">76</a><br /> - -Plateau Indians, <a href="#page_040">40-41</a>, <a href="#page_044">44-45</a>, <a href="#page_100">100</a>, <a href="#page_106">106-109</a><br /> - -Plateaus, <a href="#page_196">196-197</a><br /> - -Pleistocene deposits, <a href="#page_267">267-273</a><br /> - -Pomareni, <a href="#page_019">19</a><br /> - -Pongo de Mainique, <a href="#page_008">8</a>, <a href="#page_009">9</a>, <a href="#page_011">11</a>, <a href="#page_015">15-20</a>, <a href="#page_040">40</a>, <a href="#page_071">71</a>, <a href="#page_179">179</a>, <a href="#page_239">239</a>, <a href="#page_241">241</a>, <a href="#page_242">242</a>, <a href="#page_273">273</a>;<br /> -<span style="margin-left: 1em;">canoe in rapid above (ill.), opp. p. <a href="#page_011">11</a>;</span><br /> -<span style="margin-left: 1em;">Carboniferous, <a href="#page_244">244</a>;</span><br /> -<span style="margin-left: 1em;">dugout in rapids below (ill.), opp. p. <a href="#page_002">2</a>;</span><br /> -<span style="margin-left: 1em;">fossils, <a href="#page_322">322</a>;</span><br /> -<span style="margin-left: 1em;">temperature curve (diagr.), <a href="#page_178">178</a>;</span><br /> -<span style="margin-left: 1em;">upper entrance (ill.), opp. p. <a href="#page_010">10</a>;</span><br /> -<span style="margin-left: 1em;">vegetation, clearing, and rubber station (ill.), opp. p. <a href="#page_002">2</a></span><br /> - -Poopó, <a href="#page_195">195</a><br /> - -Potato field (ill.), opp p. <a href="#page_067">67</a><br /> - -Potatoes, <a href="#page_057">57</a>, <a href="#page_059">59</a>, <a href="#page_062">62</a><br /> - -PotosÃ, <a href="#page_249">249</a><br /> - -Precipitation. <i>See</i> Rain<br /> - -Profiles, composition of slopes and profiles (diagr.), <a href="#page_191">191</a><br /> - -Pucamoco, <a href="#page_078">78</a><br /> - -Pucapacures, <a href="#page_042">42</a><br /> - -Puerto Mainique, <a href="#page_029">29</a>, <a href="#page_030">30</a><br /> - -Punas, <a href="#page_006">6</a>, <a href="#page_197">197</a><br /> - -Puquiura, <a href="#page_067">67</a>, <a href="#page_087">87</a>, <a href="#page_211">211</a>, <a href="#page_216">216</a>, <a href="#page_236">236</a>, <a href="#page_238">238</a>, <a href="#page_239">239</a>, <a href="#page_243">243</a>, <a href="#page_277">277</a>;<br /> -<span style="margin-left: 1em;">Carboniferous, <a href="#page_244">244</a>;</span><br /> -<span style="margin-left: 1em;">composition of slopes (ill.), opp. p. <a href="#page_198">198</a></span><br /> - -Puqura, <a href="#page_250">250</a><br /> - -<br /> -<a name="Q-2" id="Q-2"></a>Quebradas, <a href="#page_145">145</a>, <a href="#page_155">155</a><br /> - -Quechuas, <a href="#page_044">44</a>, <a href="#page_045">45</a>, <a href="#page_077">77</a>, <a href="#page_083">83</a><br /> - -<i>Quenigo</i>, <a href="#page_285">285</a><br /> - -Quilca, <a href="#page_105">105</a>, <a href="#page_117">117</a>, <a href="#page_226">226</a>, <a href="#page_266">266</a><br /> - -Quillabamba, opp. p. <a href="#page_074">74</a><br /> - -Quillagua, <a href="#page_260">260</a><br /> - -<br /> -<a name="R-2" id="R-2"></a>Railroads, <a href="#page_074">74</a>, <a href="#page_075">75</a>, <a href="#page_076">76</a>, <a href="#page_093">93</a>, <a href="#page_101">101-102</a>, <a href="#page_149">149</a>;<br /> -<span style="margin-left: 1em;">Bolivia, <a href="#page_093">93</a>;</span><br /> -<span style="margin-left: 1em;">Cuzco to Santa Ana, <a href="#page_069">69-70</a></span><br /> - -Raimondi, <a href="#page_077">77</a>, <a href="#page_078">78</a>, <a href="#page_109">109</a>, <a href="#page_110">110</a>, <a href="#page_135">135</a>, <a href="#page_155">155</a>, <a href="#page_170">170</a>, <a href="#page_316">316</a><br /> - -Rain, <a href="#page_115">115</a>, <a href="#page_119">119</a>, <a href="#page_120">120</a>, <a href="#page_122">122</a>, <a href="#page_124">124-125</a>;<br /> -<span style="margin-left: 1em;">coast region seasonal variation, <a href="#page_131">131-137</a>;</span><br /> -<span style="margin-left: 1em;">eastern border of Andes, belts (diagrs.), <a href="#page_148">148</a>;</span><br /> -<span style="margin-left: 1em;">effect of heavy, <a href="#page_138">138-140</a>;</span><br /> -<span style="margin-left: 1em;">effect of sea-breeze, <a href="#page_131">131-132</a>;</span><br /> -<span style="margin-left: 1em;">heaviest, <a href="#page_147">147-148</a>;</span><br /> -<span style="margin-left: 1em;">Morococha (with diagrs.), <a href="#page_173">173-176</a>;</span><br /> -<span style="margin-left: 1em;">periodic variations, <a href="#page_137">137</a>;</span><br /> -<span style="margin-left: 1em;">Santa Lucia (with diagrs.), <a href="#page_164">164-166</a>;</span><br /> -<span style="margin-left: 1em;">unequal distribution in western Peru, <a href="#page_145">145-147</a></span><br /> - -Regional diagrams, <a href="#page_050">50</a>;<br /> -<span style="margin-left: 1em;">index map, <a href="#page_023">23</a>;</span><br /> -<span style="margin-left: 1em;">note on, <a href="#page_051">51</a></span><br /> - -Regions of Peru, <a href="#page_001">1</a>, <a href="#page_007">7</a><br /> - -Reiss, <a href="#page_205">205</a>, <a href="#page_208">208</a><br /> - -Revolutions, geographic basis, <a href="#page_088">88-109</a><br /> - -Rhone glacier, <a href="#page_205">205</a><br /> - -Rice, <a href="#page_076">76</a><br /> - -Robledo, L. M., <a href="#page_009">9</a>, <a href="#page_030">30</a>, opp. p. <a href="#page_078">78</a><br /> - -Rock belts, outline sketch along 73d meridian, <a href="#page_235">235</a><br /> - -Rocks, Maritime Cordillera, pampas and Coast Range structural relations (sketch section), <a href="#page_254">254</a>;<br /> -<span style="margin-left: 1em;">Maritime Cordillera, western border (geologic section), <a href="#page_257">257</a>;</span><br /> -<span style="margin-left: 1em;">Moquegua, structural relations (diagr.), <a href="#page_255">255</a>;</span><br /> -<span style="margin-left: 1em;">Urubamba Valley, succession (diagr.), <a href="#page_249">249</a></span><br /> - -Rosalina, <a href="#page_008">8</a>, <a href="#page_009">9</a>, <a href="#page_010">10</a>, <a href="#page_011">11</a>, <a href="#page_037">37</a>, <a href="#page_042">42</a>, <a href="#page_071">71</a>, <a href="#page_073">73</a>, <a href="#page_080">80</a>, <a href="#page_082">82</a>, <a href="#page_153">153</a>, <a href="#page_237">237</a><br /> - -Rubber, <a href="#page_018">18</a>;<br /> -<span style="margin-left: 1em;">price, <a href="#page_032">32</a>, <a href="#page_033">33</a></span><br /> - -Rubber forests, <a href="#page_022">22-35</a><br /> - -Rubber gatherers, Italian, <a href="#page_018">18</a>, <a href="#page_081">81</a><br /> - -Rubber plant (ill.), opp. p. <a href="#page_075">75</a><br /> - -Rubber trees, <a href="#page_152">152</a><br /> - -Rueda, José, <a href="#page_078">78</a><br /> - -Rug weaver (ill.), opp. p. <a href="#page_068">68</a><br /> - -Rumbold, W. R., <a href="#page_321">321</a><br /> - -Russell, I. C., <a href="#page_205">205</a><br /> - -Ruwenzori, <a href="#page_206">206</a>, <a href="#page_274">274</a><br /> - -<br /> -<a name="S-2" id="S-2"></a>Sacramento, Pampa del, <a href="#page_037">37</a><br /> - -Sahuayaco, <a href="#page_077">77</a>, <a href="#page_078">78</a>, <a href="#page_080">80</a>, <a href="#page_083">83</a>, <a href="#page_179">179</a>;<br /> -<span style="margin-left: 1em;">forests (ills.), opp. p. <a href="#page_090">90</a>;</span><br /> -<span style="margin-left: 1em;">temperature curve (diagr.), <a href="#page_178">178</a></span><br /> - -Salamanca, <a href="#page_054">54</a>, <a href="#page_056">56</a>, <a href="#page_105">105</a>, <a href="#page_106">106</a>, <a href="#page_180">180</a>, <a href="#page_181">181</a>;<br /> -<span style="margin-left: 1em;">forest, <a href="#page_285">285</a>;</span><br /> -<span style="margin-left: 1em;">temperature curve (diagr.), <a href="#page_180">180</a>;</span><br /> -<span style="margin-left: 1em;">terraced hill slopes (ill.), opp. p. <a href="#page_058">58</a>;</span><br /> -<span style="margin-left: 1em;">view (ill.), opp. p. <a href="#page_107">107</a></span><br /> - -Salaverry, <a href="#page_119">119</a><br /> - -Salcantay, <a href="#page_064">64</a>, <a href="#page_072">72</a>, opp. p. <a href="#page_003">3</a> (ill.)<br /> - -San Geronimo, <a href="#page_276">276</a><br /> - -Sand. <i>See</i> Dunes<br /> - -“Sandy matico†(ill.), opp. p. <a href="#page_090">90</a><br /> - -San Gabriel, Hacienda, <a href="#page_316">316</a><br /> - -Santa Ana, <a href="#page_069">69</a>, <a href="#page_072">72</a>, <a href="#page_078">78</a>, <a href="#page_079">79</a>, <a href="#page_080">80</a>, <a href="#page_082">82</a>, <a href="#page_093">93</a>, <a href="#page_153">153</a>, <a href="#page_179">179</a>, <a href="#page_237">237</a>;<br /> -<span style="margin-left: 1em;">clouds (ill.), opp. p. <a href="#page_180">180</a>;</span><br /> -<span style="margin-left: 1em;">temperature curve (diagr.), <a href="#page_178">178</a></span><br /> - -Santa Ana Valley, <a href="#page_010">10</a>, <a href="#page_082">82</a><br /> - -Santa Lucia, temperature ranges (diagrs.), insert opp. p. <a href="#page_162">162</a>;<br /> -<span style="margin-left: 1em;">unusual weather conditions, <a href="#page_169">169-170</a>;</span><br /> -<span style="margin-left: 1em;">weather data (with diagrs.), <a href="#page_161">161-171</a></span><br /> - -Santo Anato, <a href="#page_040">40</a>, <a href="#page_042">42</a>, <a href="#page_082">82</a>, <a href="#page_179">179</a>;<br /> -<span style="margin-left: 1em;">temperature curve (diagr.), <a href="#page_178">178</a></span><br /> - -Schists and Silurian slates, <a href="#page_236">236-241</a><br /> - -Schrund. <i>See</i> Bergschrunds<br /> - -Schrundline, <a href="#page_300">300-305</a><br /> - -Schuchert, Chas., <a href="#page_321">321</a><br /> - -Sea and land. <i>See</i> Land and sea<br /> - -Sea-breeze, <a href="#page_129">129-132</a><br /> - -Shepherd, highland, <a href="#page_004">4</a><br /> - -Shepherds, country of, <a href="#page_046">46-67</a><br /> - -Shirineiri, <a href="#page_036">36</a>, <a href="#page_038">38</a><br /> - -Sierra Nevada, <a href="#page_305">305</a><br /> - -Sierra Nevada de Santa Marta, <a href="#page_205">205</a><br /> - -Sievers, W., <a href="#page_143">143</a>, <a href="#page_176">176</a>, <a href="#page_205">205</a>, <a href="#page_263">263</a><br /> - -Sihuas, Pampa de, <a href="#page_114">114</a>, <a href="#page_198">198</a><br /> - -Sillilica, Cordillera, <a href="#page_190">190</a>, <a href="#page_260">260</a><br /> - -Sillilica Pass, <a href="#page_275">275</a><br /> - -Silurian fossils, <a href="#page_321">321</a><br /> - -Silurian slates, <a href="#page_236">236-241</a><br /> - -Sintulini rapids, <a href="#page_019">19</a><br /> - -Sirialo, <a href="#page_008">8</a>, <a href="#page_015">15</a><br /> - -Slave raiders, <a href="#page_014">14</a><br /> - -Slavery, <a href="#page_024">24</a>, <a href="#page_025">25</a><br /> - -Slopes, composition at Puquiura (ill.), opp. p. <a href="#page_198">198</a>;<br /> -<span style="margin-left: 1em;">composition of slopes and profiles (diagr.), <a href="#page_191">191</a>;</span><br /> -<span style="margin-left: 1em;">smooth grassy (ill.), opp. p. <a href="#page_079">79</a>;</span><br /> -<span style="margin-left: 1em;"><i>see also</i> Mature slopes</span><br /> - -Smallpox, <a href="#page_014">14</a>, <a href="#page_038">38</a><br /> - -Snow, <a href="#page_212">212</a>;<br /> -<span style="margin-left: 1em;">drifting, <a href="#page_278">278</a>;</span><br /> -<span style="margin-left: 1em;">fields on summit of Cordillera Vilcapampa (ill.), opp. p. <a href="#page_268">268</a></span><br /> - -Snow erosion. <i>See</i> Nivation<br /> - -Snow motion, curve of (diagr.), <a href="#page_293">293</a>;<br /> -<span style="margin-left: 1em;">law of variation, <a href="#page_291">291</a></span><br /> - -Snowline, <a href="#page_052">52</a>, <a href="#page_053">53</a>, <a href="#page_066">66</a>, <a href="#page_122">122</a>, <a href="#page_148">148</a>, <a href="#page_203">203</a>, <a href="#page_205">205-206</a>, <a href="#page_274">274-285</a>;<br /> -<span style="margin-left: 1em;">canting (with diagr.), <a href="#page_279">279</a>;</span><br /> -<span style="margin-left: 1em;">determination, <a href="#page_282">282</a>;</span><br /> -<span style="margin-left: 1em;">difference in degree of canting (diagr.), <a href="#page_281">281</a>;</span><br /> -<span style="margin-left: 1em;">glacial period, <a href="#page_282">282</a>;</span><br /> -<span style="margin-left: 1em;">view of canted, Cordillera Vilcapampa (ill.), opp. p. <a href="#page_280">280</a></span><br /> - -Snowstorm, <a href="#page_170">170</a><br /> - -Soiroccocha, <a href="#page_064">64</a>, <a href="#page_072">72</a>, <a href="#page_214">214</a>;<br /> -<span style="margin-left: 1em;">view (ill.), opp. p. <a href="#page_154">154</a></span><br /> - -Solimana, <a href="#page_004">4</a>, <a href="#page_202">202</a>, <a href="#page_317">317</a>;<br /> -<span style="margin-left: 1em;">glaciation, <a href="#page_307">307</a></span><br /> - -Soray, <a href="#page_064">64</a><br /> - -Sotospampa, <a href="#page_243">243</a><br /> - -South Pacific Ocean, <a href="#page_125">125</a><br /> - -Spanish Conquest, <a href="#page_062">62</a>, <a href="#page_063">63</a>, <a href="#page_077">77</a><br /> - -Spruce (botanist), <a href="#page_153">153</a><br /> - -Steinmann, <a href="#page_249">249</a>, <a href="#page_276">276</a><br /> - -Streams, Coast Range, <a href="#page_145">145-147</a>;<br /> -<span style="margin-left: 1em;">physiography, <a href="#page_192">192</a>;</span><br /> -<span style="margin-left: 1em;"><i>see also</i> Water</span><br /> - -Structure. <i>See</i> Rocks<br /> - -Stübel, <a href="#page_209">209</a><br /> - -Sucre, <a href="#page_093">93</a><br /> - -Sugar, <a href="#page_073">73</a>, <a href="#page_074">74</a>, <a href="#page_075">75</a>, <a href="#page_076">76</a>, <a href="#page_082">82-83</a>, <a href="#page_092">92</a><br /> - -Sullana, <a href="#page_119">119</a><br /> - -Survey methods employed in topographic sheets, <a href="#page_315">315</a><br /> - -<br /> -<a name="T-2" id="T-2"></a>Tablazo de Ica, <a href="#page_198">198</a><br /> - -Tarai. <i>See</i> Urubamba Valley<br /> - -Tarapacá, Desert of, <a href="#page_260">260</a><br /> - -Tarapoto, <a href="#page_153">153</a><br /> - -Taurisma, <a href="#page_317">317</a>;<br /> -<span style="margin-left: 1em;">geologic sketch map and cross-section, <a href="#page_248">248</a></span><br /> - -Taylor, Capt. A., <a href="#page_126">126</a>, <a href="#page_128">128</a><br /> - -Temperature, Abancay curve (diagr.), opp. p. <a href="#page_180">180</a>;<br /> -<span style="margin-left: 1em;">Callao (with diagr.), <a href="#page_126">126-129</a>;</span><br /> -<span style="margin-left: 1em;">Cochabamba, <a href="#page_176">176-178</a>;</span><br /> -<span style="margin-left: 1em;">Cochabamba (diagrs. of ranges), insert opp. p. <a href="#page_178">178</a>;</span><br /> -<span style="margin-left: 1em;">curves at various points along 73d meridian, <a href="#page_178">178-181</a>;</span><br /> -<span style="margin-left: 1em;">La Joya curves (diagr.), <a href="#page_134">134</a>;</span><br /> -<span style="margin-left: 1em;">Mollendo curves (diagr.), <a href="#page_134">134</a>;</span><br /> -<span style="margin-left: 1em;">Morococha, <a href="#page_171">171-173</a>;</span><br /> -<span style="margin-left: 1em;">Morococha (diagrs. of ranges), insert opp. p. <a href="#page_172">172</a>;</span><br /> -<span style="margin-left: 1em;">progressive lowering of saturation, in a desert (diagr.), <a href="#page_127">127</a>;</span><br /> -<span style="margin-left: 1em;">Santa Lucia, <a href="#page_161">161-164</a>;</span><br /> -<span style="margin-left: 1em;">Santa Lucia (diagrs. of ranges), insert opp. p. <a href="#page_162">162</a></span><br /> - -Tempests, <a href="#page_169">169-170</a><br /> - -Terraces, coastal, <a href="#page_225">225-232</a>;<br /> -<span style="margin-left: 1em;">physical history and physiographic development (with diagrs.), <a href="#page_228">228-230</a>;</span><br /> -<span style="margin-left: 1em;">profile at Mollendo (diagr.), <a href="#page_227">227</a></span><br /> - -Terraces, hill slopes (ill.), opp. p. <a href="#page_058">58</a><br /> - -Terraces, marine (ill.), opp. p. <a href="#page_226">226</a><br /> - -Terraces, valley (ills.), opp. p. <a href="#page_056">56</a>, opp. p. <a href="#page_057">57</a>, opp. p. <a href="#page_066">66</a>;<br /> -<span style="margin-left: 1em;">Huaynacotas (ill.), opp. p. <a href="#page_199">199</a></span><br /> - -<i>Terral</i>, <a href="#page_130">130</a><br /> - -Tertiary deposits, <a href="#page_249">249</a>, <a href="#page_251">251-267</a>;<br /> -<span style="margin-left: 1em;">coastal, <a href="#page_253">253</a></span><br /> - -Ticumpinea, <a href="#page_036">36</a>, <a href="#page_038">38</a>, <a href="#page_251">251</a><br /> - -Tierra blanca, <a href="#page_254">254</a>, <a href="#page_266">266</a><br /> - -Timber line, <a href="#page_069">69</a>, <a href="#page_071">71</a>, <a href="#page_079">79</a>, <a href="#page_148">148</a><br /> - -Timpia, <a href="#page_036">36</a>, <a href="#page_038">38</a>, <a href="#page_252">252</a>;<br /> -<span style="margin-left: 1em;">canoe at mouth (ill.), opp. p. <a href="#page_019">19</a></span><br /> - -Titicaca, <a href="#page_161">161</a>, <a href="#page_176">176</a>, <a href="#page_195">195</a>, <a href="#page_321">321</a><br /> - -Titicaca basin, <a href="#page_107">107</a><br /> - -Titicaca-Poopó basin, <a href="#page_251">251</a><br /> - -Tocate. <i>See</i> Abra Tocate<br /> - -<i>Tola</i> bush (ill.), opp. p. <a href="#page_006">6</a><br /> - -Tono, <a href="#page_036">36</a><br /> - -Topographic and climatic cross-section (diagr.), opp. p. <a href="#page_144">144</a><br /> - -Topographic and structural section of northeastern border of Andes (diagr.), <a href="#page_241">241</a><br /> - -Topographic map of the Andes between Abancay and the Pacific Coast at Camaná, insert opp. p. <a href="#page_312">312</a><br /> - -Topographic profiles across typical valleys (diagrs.), <a href="#page_189">189</a><br /> - -Topographic regions, <a href="#page_121">121-122</a>;<br /> -<span style="margin-left: 1em;">map, <a href="#page_123">123</a></span><br /> - -Topographic sheets, survey method employed, <a href="#page_315">315</a>;<br /> -<span style="margin-left: 1em;">list of, with page references, xi</span><br /> - -Topographical outfit, <a href="#page_315">315</a><br /> - -Torontoy, <a href="#page_010">10</a>, <a href="#page_070">70</a>, <a href="#page_071">71</a>, <a href="#page_072">72</a>, <a href="#page_082">82</a>, <a href="#page_158">158</a>, <a href="#page_220">220</a><br /> - -Torontoy Canyon, <a href="#page_272">272</a>, opp. p. <a href="#page_003">3</a> (ill.);<br /> -<span style="margin-left: 1em;">cliff (ill.), opp. p. <a href="#page_010">10</a></span><br /> - -Trail (mountain-side) (ill.), opp. p. <a href="#page_078">78</a><br /> - -Transportation, <a href="#page_073">73-74</a>, <a href="#page_093">93</a>, <a href="#page_152">152</a>;<br /> -<span style="margin-left: 1em;">rains and, <a href="#page_142">142</a></span><br /> - -Trees, <a href="#page_150">150</a>;<br /> -<span style="margin-left: 1em;"><i>see also</i> Forests</span><br /> - -<i>Tucapelle</i> (ship), <a href="#page_117">117</a><br /> - -Tucker, H. L., ix<br /> - -Tumbez, <a href="#page_119">119</a><br /> - -Tunari peaks, <a href="#page_276">276</a><br /> - -<br /> -<a name="U-2" id="U-2"></a>Ucayali, <a href="#page_042">42</a>, <a href="#page_044">44</a><br /> - -Uplift, recent, <a href="#page_190">190</a><br /> - -Upper Carboniferous fossils, <a href="#page_322">322</a><br /> - -Urubamba, <a href="#page_001">1</a>, <a href="#page_041">41</a>, <a href="#page_042">42</a>, <a href="#page_062">62</a>, <a href="#page_187">187</a>;<br /> -<span style="margin-left: 1em;">village, <a href="#page_070">70</a>, <a href="#page_073">73</a></span><br /> - -Urubamba River, <a href="#page_072">72</a>;<br /> -<span style="margin-left: 1em;">fossils, <a href="#page_322">322</a>;</span><br /> -<span style="margin-left: 1em;">physiographic observations, <a href="#page_252">252-253</a>;</span><br /> -<span style="margin-left: 1em;">rapids and canyons, <a href="#page_008">8-21</a>;</span><br /> -<span style="margin-left: 1em;">shelter hut (ill.), opp. p. <a href="#page_011">11</a></span><br /> - -Urubamba Valley, <a href="#page_072">72</a>, <a href="#page_153">153</a>, <a href="#page_238">238</a>;<br /> -<span style="margin-left: 1em;">alluvial fans, <a href="#page_270">270</a>;</span><br /> -<span style="margin-left: 1em;">alluvial fill, <a href="#page_272">272-273</a>;</span><br /> -<span style="margin-left: 1em;">below Paltaybamba (ill.), opp. p. <a href="#page_074">74</a>;</span><br /> -<span style="margin-left: 1em;">canyon walls (ill.), opp. p. <a href="#page_218">218</a>;</span><br /> -<span style="margin-left: 1em;">dissected alluvial fans (sketch), <a href="#page_271">271</a>;</span><br /> -<span style="margin-left: 1em;">floor from Tarai (ill.), opp. p. <a href="#page_070">70</a>;</span><br /> -<span style="margin-left: 1em;">from ice to sugar cane (ill.), opp. p. <a href="#page_003">3</a>;</span><br /> -<span style="margin-left: 1em;">geologic sketch map of the lower, <a href="#page_237">237</a>;</span><br /> -<span style="margin-left: 1em;">line of unconformity of geologic structure (ill.), opp. p. <a href="#page_250">250</a>;</span><br /> -<span style="margin-left: 1em;">rocks, <a href="#page_250">250</a>;</span><br /> -<span style="margin-left: 1em;">rocks, succession (diagr.), <a href="#page_249">249</a>;</span><br /> -<span style="margin-left: 1em;">sketch map, <a href="#page_009">9</a>;</span><br /> -<span style="margin-left: 1em;">slopes and alluvial deposits between Ollantaytambo and Torontoy (ill.), opp. p. <a href="#page_269">269</a>;</span><br /> -<span style="margin-left: 1em;">temperature curves (diagrs.), <a href="#page_178">178-179</a>;</span><br /> -<span style="margin-left: 1em;">terraced valley slopes and floor (ill.), opp. p. <a href="#page_066">66</a>;</span><br /> -<span style="margin-left: 1em;">vegetation, distribution (ill.), opp. p. <a href="#page_079">79</a>;</span><br /> -<span style="margin-left: 1em;">view below Santa Ana (ill.), opp. p. <a href="#page_155">155</a>;</span><br /> -<span style="margin-left: 1em;">wheat and bread, <a href="#page_071">71</a></span><br /> - -<br /> -<a name="V-2" id="V-2"></a>Valdivia, Señor, <a href="#page_161">161</a><br /> - -Vallenar, <a href="#page_049">49</a><br /> - -Valley climates in canyoned region (diagr.), <a href="#page_059">59</a><br /> - -Valley planters. <i>See</i> Planters<br /> - -Valley profiles, abnormal, <a href="#page_305">305-313</a><br /> - -Valleys, eastern;<br /> -<span style="margin-left: 1em;"><i>see</i> Border valleys of the Eastern Andes;</span><br /> -<span style="margin-left: 1em;"><i>see also</i> Dry valleys, Inter-Andean valleys;</span><br /> -<span style="margin-left: 1em;">topographic profiles across, typical in Southern Peru (diagrs.), <a href="#page_189">189</a></span><br /> - -Vegetation, <a href="#page_141">141</a>;<br /> -<span style="margin-left: 1em;">belts (map), <a href="#page_123">123</a>;</span><br /> -<span style="margin-left: 1em;">distribution in Urubamba Valley (ill.), opp. p. <a href="#page_079">79</a>;</span><br /> -<span style="margin-left: 1em;">shrubbery, mixed with grass (ill.), opp. p. <a href="#page_154">154</a>;</span><br /> -<span style="margin-left: 1em;">Tocate pass (ill.), opp. p. <a href="#page_019">19</a>;</span><br /> -<span style="margin-left: 1em;"><i>see also</i> Forests</span><br /> - -Vicuña, <a href="#page_054">54</a><br /> - -Vilcabamba, <a href="#page_066">66</a>;<br /> -<span style="margin-left: 1em;">rounded slopes (ill.), opp. p. <a href="#page_072">72</a></span><br /> - -Vilcabamba pueblo, <a href="#page_211">211</a>, <a href="#page_277">277</a>, <a href="#page_296">296</a><br /> - -Vilcabamba Valley, <a href="#page_189">189</a><br /> - -Vilcanota knot, <a href="#page_276">276</a><br /> - -Vilcanota Valley, alluvial fill, <a href="#page_272">272</a><br /> - -Vilcapampa, Cordillera, <a href="#page_015">15</a>, <a href="#page_016">16</a>, <a href="#page_022">22</a>, <a href="#page_051">51</a>, <a href="#page_053">53</a>, <a href="#page_064">64</a>, <a href="#page_066">66</a>, <a href="#page_067">67</a>, <a href="#page_197">197</a>, <a href="#page_204">204-224</a>, <a href="#page_233">233</a>;<br /> -<span style="margin-left: 1em;">batholith and topographic effects, <a href="#page_215">215-224</a>;</span><br /> -<span style="margin-left: 1em;">canted snowline (ill.), opp. p. <a href="#page_280">280</a>;</span><br /> -<span style="margin-left: 1em;">climatic barrier, <a href="#page_073">73</a>;</span><br /> -<span style="margin-left: 1em;">composite geologic section (diagr.), <a href="#page_215">215</a>;</span><br /> -<span style="margin-left: 1em;">glacial features, <a href="#page_204">204-214</a>;</span><br /> -<span style="margin-left: 1em;">glaciers, <a href="#page_304">304</a>;</span><br /> -<span style="margin-left: 1em;">highest pass, crossing (ill.), opp. p. <a href="#page_007">7</a>;</span><br /> -<span style="margin-left: 1em;">regional diagram, <a href="#page_065">65</a>;</span><br /> -<span style="margin-left: 1em;">regional diagram of the eastern aspect, <a href="#page_068">68</a>;</span><br /> -<span style="margin-left: 1em;">schrundline, <a href="#page_302">302</a>;</span><br /> -<span style="margin-left: 1em;">snow movement, <a href="#page_287">287-289</a>;</span><br /> -<span style="margin-left: 1em;">snow fields on summit (ill.), opp. p. <a href="#page_268">268</a>;</span><br /> -<span style="margin-left: 1em;">snow peaks (ill.), opp. p. <a href="#page_072">72</a>;</span><br /> -<span style="margin-left: 1em;">snowline, <a href="#page_277">277</a>, <a href="#page_279">279</a>;</span><br /> -<span style="margin-left: 1em;">southwestern aspect (ill.), opp. p. <a href="#page_205">205</a>;</span><br /> -<span style="margin-left: 1em;">summit view (ill.), opp. p. <a href="#page_205">205</a></span><br /> - -Vilcapampa Province, <a href="#page_077">77</a><br /> - -Vilcapampa Valley, bowldery fill, <a href="#page_269">269</a><br /> - -Vilque, <a href="#page_176">176</a><br /> - -Violle, <a href="#page_309">309</a><br /> - -<i>Virazon</i>, <a href="#page_130">130</a><br /> - -Vitor, Pampa de, <a href="#page_114">114</a>, <a href="#page_318">318</a><br /> - -Vitor River, <a href="#page_092">92</a>, <a href="#page_117">117</a>, <a href="#page_226">226</a>, <a href="#page_266">266</a>, <a href="#page_267">267</a><br /> - -Volcanic country, <a href="#page_199">199</a><br /> - -Volcanic flows, geologic sketch, <a href="#page_244">244</a><br /> - -Volcanoes, glacial erosion, <a href="#page_311">311</a>;<br /> -<span style="margin-left: 1em;">post-glacial, <a href="#page_306">306-307</a>;</span><br /> -<span style="margin-left: 1em;">recessed southern slopes (ill.), opp. p. <a href="#page_287">287</a>;</span><br /> -<span style="margin-left: 1em;">snowline, <a href="#page_281">281</a>;</span><br /> -<span style="margin-left: 1em;">typical form, <a href="#page_310">310</a>;</span><br /> -<span style="margin-left: 1em;">views (ills.), opp. p. <a href="#page_204">204</a></span><br /> - -Von Boeck, <a href="#page_176">176</a><br /> - -Vulcanism, <a href="#page_199">199</a>;<br /> -<span style="margin-left: 1em;"><i>see also</i> Volcanoes</span><br /> - -<br /> -<a name="W-2" id="W-2"></a>Ward, R. De C., <a href="#page_126">126</a>, <a href="#page_143">143</a><br /> - -Water, <a href="#page_059">59</a>, <a href="#page_060">60</a>, <a href="#page_116">116</a>, <a href="#page_139">139</a>;<br /> -<span style="margin-left: 1em;">projected canal from Atlantic to Pacific slope of the</span><br /> -<span style="margin-left: 1em;">Maritime Cordillera (diagr.), <a href="#page_118">118</a>;</span><br /> -<span style="margin-left: 1em;">streams of coastal desert, intermittent and perennial, diagrams of depth, <a href="#page_119">119</a></span><br /> - -Water skippers, <a href="#page_017">17</a><br /> - -Watkins, Mr., <a href="#page_317">317</a>, <a href="#page_318">318</a><br /> - -Weather. <i>See</i> Meteorological records<br /> - -Western Andes, <a href="#page_199">199-203</a><br /> - -Whymper, <a href="#page_205">205</a><br /> - -Wind belts, <a href="#page_122">122</a>;<br /> -<span style="margin-left: 1em;">map, <a href="#page_123">123</a></span><br /> - -Wind roses, Callao (diagrs.), <a href="#page_128">128</a>;<br /> -<span style="margin-left: 1em;">Caraveli (diagrs.), <a href="#page_136">136</a>;</span><br /> -<span style="margin-left: 1em;">Iquique (diagrs.), <a href="#page_131">131</a>;</span><br /> -<span style="margin-left: 1em;">La Joya (diagrs.), <a href="#page_135">135</a>;</span><br /> -<span style="margin-left: 1em;">Machu Picchu (diagrs.), <a href="#page_159">159</a>;</span><br /> -<span style="margin-left: 1em;">Mollendo (diagrs.), <a href="#page_129">129</a>;</span><br /> -<span style="margin-left: 1em;">Santa Lucia (diagrs.), <a href="#page_167">167</a>;</span><br /> -<span style="margin-left: 1em;">summer and winter of 1911-1913 (diagrs.), <a href="#page_130">130</a></span><br /> - -Winds, <a href="#page_114">114</a>, <a href="#page_116">116</a>;<br /> -<span style="margin-left: 1em;">directions at Machu Picchu, <a href="#page_158">158-159</a>;</span><br /> -<span style="margin-left: 1em;">geologic action, <a href="#page_262">262-267</a>;</span><br /> -<span style="margin-left: 1em;">prevailing, <a href="#page_125">125</a>;</span><br /> -<span style="margin-left: 1em;">Santa Lucia (with diagrs.), <a href="#page_166">166-168</a>;</span><br /> -<span style="margin-left: 1em;">trade, <a href="#page_122">122</a>, <a href="#page_124">124</a>;</span><br /> -<span style="margin-left: 1em;">sea-breeze, <a href="#page_129">129-132</a></span><br /> - -Wine, <a href="#page_116">116</a>, <a href="#page_117">117</a><br /> - -Wolf, <a href="#page_205">205</a><br /> - -<br /> -<a name="Y-2" id="Y-2"></a>Yanahuara pass, <a href="#page_170">170</a><br /> - -Yanatili, <a href="#page_041">41</a>, <a href="#page_042">42</a>, <a href="#page_044">44</a>;<br /> -<span style="margin-left: 1em;">slopes at junction with Urubamba River (ill.), opp. p. <a href="#page_079">79</a></span><br /> - -<i>Yareta</i> (ill.), opp. p. <a href="#page_006">6</a><br /> - -Yavero, <a href="#page_030">30</a>, <a href="#page_031">31</a>, <a href="#page_036">36</a>, <a href="#page_038">38</a>, <a href="#page_042">42</a>, <a href="#page_179">179</a>;<br /> -<span style="margin-left: 1em;">temperature curve (diagr.), <a href="#page_178">178</a></span><br /> - -Yavero (Paucartambo) River, rubber station (ill.), opp. p. <a href="#page_024">24</a><br /> - -Yuca, growing (ill.), opp. p. <a href="#page_075">75</a><br /> - -Yunguyo, <a href="#page_176">176</a><br /> - -Yuyato, <a href="#page_036">36</a>, <a href="#page_038">38</a><br /> -</p> - -<div class="footnotes"><p class="cb">FOOTNOTES:</p> - -<div class="footnote"><p><a name="Footnote_1_1" id="Footnote_1_1"></a><a href="#FNanchor_1_1"><span class="label">[1]</span></a> For all locations mentioned see maps accompanying the text -or Appendix C.</p></div> - -<div class="footnote"><p><a name="Footnote_2_2" id="Footnote_2_2"></a><a href="#FNanchor_2_2"><span class="label">[2]</span></a> The Cashibos of the Pachitea are the tribe for whom the -Piros besought Herndon to produce “some great and infectious disease†-which could be carried up the river and let loose amongst them (Herndon, -Exploration of the Valley of the Amazon, Washington. 1854, Vol. 1, p. -196). This would-be artfulness suggests itself as something of a match -against the cunning of the Cashibos whom rumor reports to imitate the -sounds of the forest animals with such skill as to betray into their -hands the hunters of other tribes (see von Tschudi, Travels in Peru -During the Years 1838-1842, translated from the German by Thomasina -Ross, New York, 1849, p. 404).</p></div> - -<div class="footnote"><p><a name="Footnote_3_3" id="Footnote_3_3"></a><a href="#FNanchor_3_3"><span class="label">[3]</span></a> The early chronicles contain several references to Antisuyu -and the Antis. Garcilaso de la Vega’s description of the Inca conquests -in Antisuyu are well known (Royal Commentaries of the Yncas, Book 4, -Chapters 16 and 17, Hakluyt Soc. Publs., 1st Ser., No. 41, 1869 and Book -7, Chapters 13 and 14, No. 45, 1871). Salcamayhua who also chronicles -these conquests relates a legend concerning the tribute payers of the -eastern valleys. On one occasion, he says, three hundred Antis came -laden with gold from Opatari. Their arrival at Cuzco was coincident with -a killing frost that ruined all the crops of the basin whence the three -hundred fortunates were ordered with their gold to the top of the high -hill of Pachatucsa (Pachatusun) and there buried with it (An Account of -the Antiquities of Peru, Hakluyt Soc. Publs., 1st Ser., No. 48, 1873).</p></div> - -<div class="footnote"><p><a name="Footnote_4_4" id="Footnote_4_4"></a><a href="#FNanchor_4_4"><span class="label">[4]</span></a> Notice of a Journey to the Northward and also to the -Northeastward of Cuzco. Royal Geog. Soc. Journ., Vol. 6, 1836, pp. -174-186.</p></div> - -<div class="footnote"><p><a name="Footnote_5_5" id="Footnote_5_5"></a><a href="#FNanchor_5_5"><span class="label">[5]</span></a> Walle states (Le Pérou Economique, Paris, 1907, p. 297) -that the Conibos, a tribe of the Ucayali, make annual <i>correrias</i> or -raids during the months of July, August, and September, that is during -the season of low water. Over seven hundred canoes are said to -participate and the captives secured are sold to rubber exploiters, who, -indeed, frequently aid in the organization of the raids.</p></div> - -<div class="footnote"><p><a name="Footnote_6_6" id="Footnote_6_6"></a><a href="#FNanchor_6_6"><span class="label">[6]</span></a> Distances are not taken from the map but from the trail.</p></div> - -<div class="footnote"><p><a name="Footnote_7_7" id="Footnote_7_7"></a><a href="#FNanchor_7_7"><span class="label">[7]</span></a> Compare with Raimondi’s description of Quiches on the left -bank of the Marañon at an elevation of 9,885 feet (3,013 m.): “the few -small springs scarcely suffice for the little patches of alfalfa and -other sowings have to depend on the precarious rains.... Every drop of -water is carefully guarded and from each spring a series of well-like -basins descending in staircase fashion make the most of the scant -supply.†(El Departamento de Ancachs, Lima, 1873.)</p></div> - -<div class="footnote"><p><a name="Footnote_8_8" id="Footnote_8_8"></a><a href="#FNanchor_8_8"><span class="label">[8]</span></a> Daily Cons. and Trade Report, June 10, 1914, No. 135, and -Commerce Reports, March 20, 1916, No. 66.</p></div> - -<div class="footnote"><p><a name="Footnote_9_9" id="Footnote_9_9"></a><a href="#FNanchor_9_9"><span class="label">[9]</span></a> Reference to the figures in this chapter will show great -variation in the level of the timber line depending upon insolation as -controlled by slope exposure and upon moisture directly as controlled -largely by exposure to winds. In some places these controls counteract -each other; in other places they promote each other’s effects. The -topographic and climatic cross-sections and regional diagrams elsewhere -in this book also emphasize the patchiness of much of the woodland and -scrub, some noteworthy examples occurring in the chapter on the Eastern -Andes. Two of the most remarkable cases are the patch of woodland at -14,500 feet (4,420 m.) just under the hanging glacier of Soiroccocha, -and the other the quenigo scrub on the lava plateau above Chuquibamba at -13,000 feet (3,960 m.). The strong compression of climatic zones in the -Urubamba Valley below Santa Ana brings into sharp contrast the grassy -ridge slopes facing the sun and the forested slopes that have a high -proportion of shade. <a href="#fig_54">54</a> represents the general distribution but the -details are far more complicated. See also Figs. 53A and 53B. (See -Coropuna Quadrangle.)</p></div> - -<div class="footnote"><p><a name="Footnote_10_10" id="Footnote_10_10"></a><a href="#FNanchor_10_10"><span class="label">[10]</span></a> Commenting on the excellence of the cacao of the montaña -of the Urubamba von Tschudi remarked (op. cit., p. 37) that the long -land transport prevented its use in Lima where the product on the market -is that imported from Guayaquil.</p></div> - -<div class="footnote"><p><a name="Footnote_11_11" id="Footnote_11_11"></a><a href="#FNanchor_11_11"><span class="label">[11]</span></a> The inadequacy of the labor supply was a serious obstacle -in the early days as well as now. In the documents pertaining to the -“Obispados y Audiencia del Cuzco†(Vol. 11, p. 349 of the “Juicio de -Limites entre el Perú y Bolivia, Prueba Peruana presentada al Gobierno -de la República Argentina por Victor M. Maurtua,†Barcelona, 1900) we -find the report that the natives of the curacy of Ollantaytambo who came -down from the hills to Huadquiña to hear mass were detained and -compelled to give a day’s service on the valley plantations under pain -of chastisement.</p></div> - -<div class="footnote"><p><a name="Footnote_12_12" id="Footnote_12_12"></a><a href="#FNanchor_12_12"><span class="label">[12]</span></a> The Spanish occupation of the eastern valleys was early -and extensive. Immediately after the capture of the young Inca Tupac -Amaru and the final subjugation of the province of Vilcapampa colonists -started the cultivation of coca and cane. Development of the main -Urubamba Valley and tributary valleys proceeded at a good rate: so also -did their troubles. Baltasar de Ocampo writing in 1610 (Account of the -Province of Vilcapampa, Hakluyt Soc. Publs., Ser. 2, Vol. 22, 1907, pp. -203-247) relates the occurrence of a general uprising of the negroes -employed on the sugar plantations of the region. But the peace and -prosperity of every place on the eastern frontier was unstable and quite -generally the later eighteenth and earlier nineteenth centuries saw a -retreat of the border of civilization. The native rebellion of the -mid-eighteenth century in the montaña of Chanchamayo caused entire -abandonment of a previously flourishing area. When Raimondi wrote in -1885 (La Montaña de Chanchamayo, Lima, 1885) some of the ancient -hacienda sites were still occupied by savages. In the Paucartambo -valleys, settlement began by the end of the sixteenth century and at the -beginning of the nineteenth before their complete desolation by the -savages they were highly prosperous. Paucartambo town, itself, once -important for its commerce in coca is now in a sadly decadent -condition.</p></div> - -<div class="footnote"><p><a name="Footnote_13_13" id="Footnote_13_13"></a><a href="#FNanchor_13_13"><span class="label">[13]</span></a> Notice of a Journey to the Northward and also to the -Eastward of Cuzco, and among the Chunchos Indians, in July, 1835. Journ. -Royal Geog. Soc., Vol. 6, 1836, pp. 174-186.</p></div> - -<div class="footnote"><p><a name="Footnote_14_14" id="Footnote_14_14"></a><a href="#FNanchor_14_14"><span class="label">[14]</span></a> Bol. Soc. Geog. de Lima, Vol. 8, 1898, p. 45.</p></div> - -<div class="footnote"><p><a name="Footnote_15_15" id="Footnote_15_15"></a><a href="#FNanchor_15_15"><span class="label">[15]</span></a> Marcoy who traveled in Peru in the middle of the last -century was greatly impressed by the sympathetic changes of aspect and -topography and vegetation in the eastern valleys. He thus describes a -sudden change of scene in the Occobamba valley: “... the trees had -disappeared, the birds had taken wing, and great sandy spaces, covered -with the latest deposits of the river, alternated with stretches of -yellow grass and masses of rock half-buried in the ground.†(Travels in -South America, translated by Elihu Rich, 2 vols. New York, 1875, Vol. 1, -p. 326.)</p></div> - -<div class="footnote"><p><a name="Footnote_16_16" id="Footnote_16_16"></a><a href="#FNanchor_16_16"><span class="label">[16]</span></a> According to the latest information (August, 1916) of the -Bolivia Railway Co., trains are running from Oruro to Buen Retiro, 35 -km. from Cochabamba. Thence connection with Cochabamba is made by a -tram-line operated by the Electric Light and Power Co. of that city. The -Bulletin of the Pan-American Union for July, 1916, also reports the -proposed introduction of an automobile service for conveyance of freight -and passengers.</p></div> - -<div class="footnote"><p><a name="Footnote_17_17" id="Footnote_17_17"></a><a href="#FNanchor_17_17"><span class="label">[17]</span></a> During his travels Raimondi collected many instances of -the isolation and conservatism of the plateau Indian: thus there is the -village of Pampacolca near Coropuna, whose inhabitants until recently -carried their idols of clay to the slopes of the great white mountain -and worshiped them there with the ritual of Inca days (El Perú, Lima, -1874, Vol. 1).</p></div> - -<div class="footnote"><p><a name="Footnote_18_18" id="Footnote_18_18"></a><a href="#FNanchor_18_18"><span class="label">[18]</span></a> Raimondi (op. cit., p. 109) has a characteristic -description of the “Camino del Peñon†in the department of La Libertad: -“... the ground seems to disappear from one’s feet; one is standing on -an elevated balcony looking down more than 6,000 feet to the valley ... -the road which descends the steep scarp is a masterpiece.â€</p></div> - -<div class="footnote"><p><a name="Footnote_19_19" id="Footnote_19_19"></a><a href="#FNanchor_19_19"><span class="label">[19]</span></a> Figs. 67 and 68 are from Bol. de Minas del Perú, 1906, No. -37, pp. 82 and 84 respectively.</p></div> - -<div class="footnote"><p><a name="Footnote_20_20" id="Footnote_20_20"></a><a href="#FNanchor_20_20"><span class="label">[20]</span></a> The BoletÃn de Minas del Peru, No. 34, 1905, contains a -graphic representation of the régime of the Rio Chili at Arequipa for -the years 1901-1905.</p></div> - -<div class="footnote"><p><a name="Footnote_21_21" id="Footnote_21_21"></a><a href="#FNanchor_21_21"><span class="label">[21]</span></a> Hann (Handbook of Climatology, translated by R. De C. -Ward, New York, 1903) indicates a contributory cause in the upwelling of -cold water along the coast caused by the steady westerly drift of the -equatorial current.</p></div> - -<div class="footnote"><p><a name="Footnote_22_22" id="Footnote_22_22"></a><a href="#FNanchor_22_22"><span class="label">[22]</span></a> This is the elevation obtained by the Peruvian Expedition. -Raimondi’s figure (1,832 m.) is higher.</p></div> - -<div class="footnote"><p><a name="Footnote_23_23" id="Footnote_23_23"></a><a href="#FNanchor_23_23"><span class="label">[23]</span></a> According to Ward’s observations the base of the cloud -belt averages between 2,000 and 3,000 feet above sea level (Climatic -Notes Made During a Voyage Around South America, Journ. of School -Geogr., Vol. 2, 1898). On the south Peruvian coast, specifically at -Mollendo, Middendorf found the cloud belt beginning about 1,000 feet and -extending upwards to elevations of 3,000 to 4,000 feet. At Lima the -clouds descend to lower levels (El Clima de Lima, Bol. Soc. Geogr. de -Lima, Vol. 15, 1904). In the third edition of his Süd und Mittelamerika -(Leipzig and Vienna, 1914) Sievers says that at Lima in the winter the -cloud on the coast does not exceed an elevation of 450 m. (1,500 feet) -while on the hills it lies at elevations between 300 and 700 m. (1,000 -and 2,300 feet).</p></div> - -<div class="footnote"><p><a name="Footnote_24_24" id="Footnote_24_24"></a><a href="#FNanchor_24_24"><span class="label">[24]</span></a> In most of the coast towns the ford or ferry is an -important institution and the <i>chimbadores</i> or <i>baleadores</i> as they are -called are expert at their trade: they know the régime of the rivers to -a nicety. Several settlements owe their origin to the exigencies of -transportation, permanent and periodic; thus before the development of -its irrigation system Camaná, according to General Miller (Memoirs, -London, 1829, Vol. 2, p. 27), was a hamlet of some 30 people who gained -their livelihood through ferrying freight and passengers across the -Majes River.</p></div> - -<div class="footnote"><p><a name="Footnote_25_25" id="Footnote_25_25"></a><a href="#FNanchor_25_25"><span class="label">[25]</span></a> A dry pocket in the Huallaga basin between 6° and 7° S. is -described by Spruce (Notes of a Botanist on the Amazon and Andes, 2 -vols., London, 1908). Tarapoto at an elevation of 1,500 feet above sea -level, encircled by hills rising 2,000 to 3,000 feet higher, rarely -experiences heavy rain though rain falls frequently on the hills.</p></div> - -<div class="footnote"><p><a name="Footnote_26_26" id="Footnote_26_26"></a><a href="#FNanchor_26_26"><span class="label">[26]</span></a> Speaking of Cómas situated at the headwaters of a source -of the Perene amidst a multitude of <i>quebradas</i> Raimondi (op. cit., p. -109) says it “might properly be called the town of the clouds, for there -is not a day during the year, at any rate towards the evening, when the -town is not enveloped in a mist sufficient to hide everything from -view.â€</p></div> - -<div class="footnote"><p><a name="Footnote_27_27" id="Footnote_27_27"></a><a href="#FNanchor_27_27"><span class="label">[27]</span></a> Observer: E. C. Erdis of the 1912 and 1914-15 -Expeditions.</p></div> - -<div class="footnote"><p><a name="Footnote_28_28" id="Footnote_28_28"></a><a href="#FNanchor_28_28"><span class="label">[28]</span></a> Percentages given because the number of observations -varies.</p></div> - -<div class="footnote"><p><a name="Footnote_29_29" id="Footnote_29_29"></a><a href="#FNanchor_29_29"><span class="label">[29]</span></a> Observer: Señor Valdivia. For location of Santa Lucia see -Fig. 66.</p></div> - -<div class="footnote"><p><a name="Footnote_30_30" id="Footnote_30_30"></a><a href="#FNanchor_30_30"><span class="label">[30]</span></a> Observations began on May 12.</p></div> - -<div class="footnote"><p><a name="Footnote_31_31" id="Footnote_31_31"></a><a href="#FNanchor_31_31"><span class="label">[31]</span></a> For the first half of the month only; no record for the -second half.</p></div> - -<div class="footnote"><p><a name="Footnote_32_32" id="Footnote_32_32"></a><a href="#FNanchor_32_32"><span class="label">[32]</span></a> BoletÃn de la Sociedad Geográfica de Lima, Vol. 13, pp. -473-480, Lima, 1903.</p></div> - -<div class="footnote"><p><a name="Footnote_33_33" id="Footnote_33_33"></a><a href="#FNanchor_33_33"><span class="label">[33]</span></a> BoletÃn del Cuerpo de Ingenieros de Minas del Perú, No. -34, Lima, 1905, also reproduced in No. 45, 1906.</p></div> - -<div class="footnote"><p><a name="Footnote_34_34" id="Footnote_34_34"></a><a href="#FNanchor_34_34"><span class="label">[34]</span></a> The record is copied literally without regard to the -absurdity of the second and third decimal places.</p></div> - -<div class="footnote"><p><a name="Footnote_35_35" id="Footnote_35_35"></a><a href="#FNanchor_35_35"><span class="label">[35]</span></a> In the Eastern Cordillera, however, snowstorms may be more -serious. Prior to the construction of the Urubamba Valley Road by the -Peruvian government the three main routes to the Santa Ana portion of -the valley proceeded via the passes of Salcantay, Panticalla, and -Yanahuara respectively. Frequently all are completely snow-blocked and -fatalities are by no means unknown. In 1864 for instance nine persons -succumbed on the Yanahuara pass (Raimondi, op. cit., p. 109).</p></div> - -<div class="footnote"><p><a name="Footnote_36_36" id="Footnote_36_36"></a><a href="#FNanchor_36_36"><span class="label">[36]</span></a> BoletÃn de la Sociedad Geográfica de Lima, Vol. 27, 1911; -Vol. 28, 1912.</p></div> - -<div class="footnote"><p><a name="Footnote_37_37" id="Footnote_37_37"></a><a href="#FNanchor_37_37"><span class="label">[37]</span></a> BoletÃn del Cuerpo de Ingenieros de Minas del Perú, No. -65, 1908.</p></div> - -<div class="footnote"><p><a name="Footnote_38_38" id="Footnote_38_38"></a><a href="#FNanchor_38_38"><span class="label">[38]</span></a> This figure is approximate: some days’ records were -missing from the first three months of the year and the total was -estimated on a proportional basis.</p></div> - -<div class="footnote"><p><a name="Footnote_39_39" id="Footnote_39_39"></a><a href="#FNanchor_39_39"><span class="label">[39]</span></a> Christoval de Molina, The Fables and Rites of the Yncas, -Hakluyt Soc. Publs., 1st Ser., No. 48, 1873.</p></div> - -<div class="footnote"><p><a name="Footnote_40_40" id="Footnote_40_40"></a><a href="#FNanchor_40_40"><span class="label">[40]</span></a> See Meteorologische Zeitschrift, Vol. 5, p. 195, 1888. -Also cited by J. Hann in Handbuch der Climatologie, Vol. 2, Stuttgart, -1897; W. Sievers, Süd und Mittelamerika, Leipzig and Vienna, 1914, p. -334.</p></div> - -<div class="footnote"><p><a name="Footnote_41_41" id="Footnote_41_41"></a><a href="#FNanchor_41_41"><span class="label">[41]</span></a> The Physiography of the Central Andes, Am. Journ. Sci., -Vol. 40, 1909, pp. 197-217 and 373-402.</p></div> - -<div class="footnote"><p><a name="Footnote_42_42" id="Footnote_42_42"></a><a href="#FNanchor_42_42"><span class="label">[42]</span></a> Results of an Expedition to the Central Andes, Bull. Am. -Geog. Soc., Vol. 46, 1914. Figs. 28 and 29.</p></div> - -<div class="footnote"><p><a name="Footnote_43_43" id="Footnote_43_43"></a><a href="#FNanchor_43_43"><span class="label">[43]</span></a> The Physiography of the Central Andes, by Isaiah Bowman; -Am. Journ. Sci., Vol. 28, 1909, pp. 197-217 and 373-402. See especially, -<i>ibid.</i>, Fig. 11, p. 216.</p></div> - -<div class="footnote"><p><a name="Footnote_44_44" id="Footnote_44_44"></a><a href="#FNanchor_44_44"><span class="label">[44]</span></a> Travels Amongst the Great Andes of the Equator, 1892.</p></div> - -<div class="footnote"><p><a name="Footnote_45_45" id="Footnote_45_45"></a><a href="#FNanchor_45_45"><span class="label">[45]</span></a> GeografÃa y GeologÃa del Ecuador, 1892.</p></div> - -<div class="footnote"><p><a name="Footnote_46_46" id="Footnote_46_46"></a><a href="#FNanchor_46_46"><span class="label">[46]</span></a> Das Hochgebirge der Republik Ecuador, Vol. 2, 2 -Ost-Cordillera, 1902, p. 162.</p></div> - -<div class="footnote"><p><a name="Footnote_47_47" id="Footnote_47_47"></a><a href="#FNanchor_47_47"><span class="label">[47]</span></a> Contributions to the Geology of British East Africa; Pt. -1, The Glacial Geology of Mount Kenia, Quart. Journ. Geol. Soc., Vol. -50, 1894, p. 523.</p></div> - -<div class="footnote"><p><a name="Footnote_48_48" id="Footnote_48_48"></a><a href="#FNanchor_48_48"><span class="label">[48]</span></a> See especially A. Penck (Penck and Brückner), Die Alpen im -Eiszeitalter, 1909, Vol. 1, p. 6, and I. C. Russell, Glaciers of Mount -Rainier, 18th Ann. Rep’t, U. S. Geol. Surv., 1890-97, Sect. 2, pp. -384-385.</p></div> - -<div class="footnote"><p><a name="Footnote_49_49" id="Footnote_49_49"></a><a href="#FNanchor_49_49"><span class="label">[49]</span></a> Die Sierra Nevada de Santa Marta und die Sierra de Perijá, -Zeitschrift der Gesellschaft für Erdkunde zu Berlin, Vol. 23, 1888, pp. -1-158.</p></div> - -<div class="footnote"><p><a name="Footnote_50_50" id="Footnote_50_50"></a><a href="#FNanchor_50_50"><span class="label">[50]</span></a> For a list of the fossils that form the basis of the age -determinations in this chapter see <a href="#APPENDIX_B">Appendix B</a>.</p></div> - -<div class="footnote"><p><a name="Footnote_51_51" id="Footnote_51_51"></a><a href="#FNanchor_51_51"><span class="label">[51]</span></a> Eastern Bolivia and the Gran Chaco, Proc. Royal Geogr. -Soc., Vol. 3, 1881, pp. 401-420.</p></div> - -<div class="footnote"><p><a name="Footnote_52_52" id="Footnote_52_52"></a><a href="#FNanchor_52_52"><span class="label">[52]</span></a> The Physiography of the Central Andes, Am. Journ. Sci., -Vol. 28, 1909, p. 395.</p></div> - -<div class="footnote"><p><a name="Footnote_53_53" id="Footnote_53_53"></a><a href="#FNanchor_53_53"><span class="label">[53]</span></a> See paper by H. S. Palmer, my assistant on the Expedition -to the Central Andes, 1913, entitled: Geological Notes on the Andes of -Northwestern Argentina, Am. Journ. Sci., Vol. 38, 1914, pp. 309-330.</p></div> - -<div class="footnote"><p><a name="Footnote_54_54" id="Footnote_54_54"></a><a href="#FNanchor_54_54"><span class="label">[54]</span></a> The best photograph of this condition which I have yet -seen is in W. Sievers, Südund Mittelamerika, second ed., 1914, Plate 15, -p. 358.</p></div> - -<div class="footnote"><p><a name="Footnote_55_55" id="Footnote_55_55"></a><a href="#FNanchor_55_55"><span class="label">[55]</span></a> Paschinger, Die Schneegrenze in verschiedenen Klimaten. -Peter. Mitt. Erganz’heft, Nr. 173. 1912, pp. 92-93.</p></div> - -<div class="footnote"><p><a name="Footnote_56_56" id="Footnote_56_56"></a><a href="#FNanchor_56_56"><span class="label">[56]</span></a> Hann, Handbook of Climatology, Part 1, trans. by Ward, -1903, p. 232.</p></div> - -<div class="footnote"><p><a name="Footnote_57_57" id="Footnote_57_57"></a><a href="#FNanchor_57_57"><span class="label">[57]</span></a> S. I. Bailey, Peruvian Meteorology, 1888-1890. Ann. -Astron. Observ. of Harvard Coll., Vol. 39, Pt. I, 1899, pp. 1-3.</p></div> - -<div class="footnote"><p><a name="Footnote_58_58" id="Footnote_58_58"></a><a href="#FNanchor_58_58"><span class="label">[58]</span></a> F. E. Matthes, Glacial Sculpture of the Bighorn Mountains, -Wyoming, Twentieth Ann. Rept. U. S. Geol. Surv., 1899-1900, Pt. 2, p. -181.</p></div> - -<div class="footnote"><p><a name="Footnote_59_59" id="Footnote_59_59"></a><a href="#FNanchor_59_59"><span class="label">[59]</span></a> Idem, p. 190.</p></div> - -<div class="footnote"><p><a name="Footnote_60_60" id="Footnote_60_60"></a><a href="#FNanchor_60_60"><span class="label">[60]</span></a> W. H. Hobbs, Characteristics of Existing Glaciers, 1911, -p. 22.</p></div> - -<div class="footnote"><p><a name="Footnote_61_61" id="Footnote_61_61"></a><a href="#FNanchor_61_61"><span class="label">[61]</span></a> Op. cit., p. 286. Reference on p. 190.</p></div> - -<div class="footnote"><p><a name="Footnote_62_62" id="Footnote_62_62"></a><a href="#FNanchor_62_62"><span class="label">[62]</span></a> Corrosion of Gravity Streams with Application of the Ice -Flood Hypothesis, Journ. and Proc. of the Royal Society of N. S. Wales, -Vol. 43, 1909, p. 286.</p></div> - -<div class="footnote"><p><a name="Footnote_63_63" id="Footnote_63_63"></a><a href="#FNanchor_63_63"><span class="label">[63]</span></a> G. K. Gilbert, Systematic Asymmetry of Crest Lines in the -High Sierra of California. Jour. Geol., Vol. 12, 1904, p. 582.</p></div> - -<div class="footnote"><p><a name="Footnote_64_64" id="Footnote_64_64"></a><a href="#FNanchor_64_64"><span class="label">[64]</span></a> Op. cit., p. 300; reference on p. 582.</p></div> - -<div class="footnote"><p><a name="Footnote_65_65" id="Footnote_65_65"></a><a href="#FNanchor_65_65"><span class="label">[65]</span></a> Op. cit., p. 300; see pp. 579-588 and Fig. 8.</p></div> - -<div class="footnote"><p><a name="Footnote_66_66" id="Footnote_66_66"></a><a href="#FNanchor_66_66"><span class="label">[66]</span></a> The observation at Camaná checks very closely with a -Peruvian observation the value of which is S. 16° 37′ 00″.</p></div> - -</div> -<hr class="full" /> - - - - - - - -<pre> - - - - - -End of Project Gutenberg's The Andes of Southern Peru, by Isaiah Bowman - -*** END OF THIS PROJECT GUTENBERG EBOOK THE ANDES OF SOUTHERN PERU *** - -***** This file should be named 42860-h.htm or 42860-h.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/4/2/8/6/42860/ - -Produced by Chuck Greif, The University of Florida Digital -Collections and the Online Distributed Proofreading Team -at http://www.pgdp.net - - -Updated editions will replace the previous one--the old editions -will be renamed. - -Creating the works from public domain print editions means that no -one owns a United States copyright in these works, so the Foundation -(and you!) can copy and distribute it in the United States without -permission and without paying copyright royalties. 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href="https://github.com/gutenbergbooks/42860">https://github.com/gutenbergbooks/42860</a> -</div> -</body> -</html> |
