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+*** START OF THE PROJECT GUTENBERG EBOOK 43826 ***
+
+Transcriber's note:
+    Minor spelling inconsistencies, mainly hyphenated words, have been
+    harmonized. Italic text has been marked with _underscores_.
+    Obvious typos have been corrected. Please see the end of this book
+    for further notes.
+
+
+
+
+THE STORY OF THE HILLS.
+
+
+
+
+  [Illustration]
+
+
+
+
+  [Illustration: NORHAM CASTLE. AFTER TURNER.]
+
+
+
+
+    THE
+
+    STORY OF THE HILLS.
+
+    A BOOK ABOUT MOUNTAINS
+    FOR GENERAL READERS.
+
+    BY
+
+    REV. H. N. HUTCHINSON, B.A., F.G.S.
+
+    AUTHOR OF "THE AUTOBIOGRAPHY OF THE EARTH."
+
+    With Sixteen Full-page Illustrations.
+
+They are as a great and noble architecture, first giving shelter,
+comfort, and rest; and covered also with mighty sculpture and painted
+legend.--RUSKIN.
+
+    New York:
+    MACMILLAN AND CO.
+    AND LONDON.
+
+    1892.
+
+
+
+
+    _Copyright, 1891_,
+    BY MACMILLAN AND CO.
+
+
+    University Press:
+    JOHN WILSON AND SON, CAMBRIDGE, U.S.A.
+
+
+
+
+TO
+
+ALL WHO LOVE MOUNTAINS AND HILLS
+
+This little Book is Dedicated,
+
+   IN THE HOPE THAT EVEN A SLIGHT KNOWLEDGE OF THEIR PLACE IN
+   NATURE, AND PREVIOUS HISTORY, MAY ADD TO THE WONDER AND DELIGHT
+   WITH WHICH WE LOOK UPON THESE NOBLE FEATURES OF THE SURFACE OF
+   THE EARTH.
+
+
+
+PREFACE.
+
+
+Now that travelling is no longer a luxury for the rich, and thousands
+of people go every summer to spend their holidays among the
+mountains of Europe, and ladies climb Mont Blanc or ramble among the
+Carpathians, there must be many who would like to know something of
+the secret of the hills, their origin, their architecture, and the
+forces that made them what they are.
+
+For such this book is chiefly written. Those will best understand it
+who take it with them on their travels, and endeavour by its use to
+interpret what they see among the mountains; and they will find that
+a little observation goes a long way to help them to read mountain
+history.
+
+It is hoped, however, that all, both young and old, who take an
+intelligent interest in the world around, though they may never have
+seen a mountain, may find these pages worth reading.
+
+If readers do not find here answers to all their questions, they
+may be reminded that it is not possible within the present limits
+to give more than a brief sketch of the subject, leaving the gaps
+to be filled in by a study of the larger and more important works
+on geology. The author, assuming that the reader knows nothing of
+this fascinating science, has endeavoured to interpret into ordinary
+language the story of the hills as it is written in the rocks of
+which they are made.
+
+It can scarcely be denied that a little knowledge of natural objects
+greatly adds to our appreciation of them, besides affording a deep
+source of pleasure, in revealing the harmony, law, and order by which
+all things in this wonderful world are governed. Mountains, when
+once we begin to observe them, seem to become more than ever our
+companions,--to take us into their counsels, and to teach us many a
+lesson about the great part they play in the order of things. And
+surely our admiration of their beauty is not lessened, but rather
+increased, when we learn how much we and all living things owe to
+the life-giving streams that flow continually from them. The writer
+has, somewhat reluctantly, omitted certain parts of the subject
+which, though very interesting to the geologist, can hardly be made
+attractive to general readers.
+
+Thus, the cause of earth movements, by which mountains are pushed up
+far above the plains that lie at their feet, is at present a matter
+of speculation; and it is difficult to express in ordinary language
+the ideas that have been put forward on this subject. Again, the
+curious internal changes, which we find to have taken place in the
+rocks of which mountains are composed, are very interesting to those
+who know something of the minerals of which rocks are made up, and
+their chemical composition; but it was found impossible to render
+these matters sufficiently simple.
+
+So again with regard to the geological structure of mountain-chains.
+This had to be very briefly treated, in order to avoid introducing
+details which would be too complicated for a book of this kind.
+
+The author desires to acknowledge his obligations to the writings
+of Sir A. Geikie; Professor Bonney, Professor Green, and Professor
+Shaler, of Harvard University; the volumes of the "Alpine Journal;"
+"The Earth," by Reclus; the "Encyclopædia Britannica." Canon Isaac
+Taylor's "Words and Places," have also been made use of; and if in
+every case the reference is not given, the writer hopes the omission
+will be pardoned. A few passages from Mr. Ruskin's "Modern Painters"
+have been quoted, in the hope that others may be led to read that
+wonderful book, and to learn more about mountains and clouds, and
+many other things, at the feet of one of the greatest teachers of the
+century.
+
+Some of our engravings are taken from the justly celebrated
+photographs of the High Alps,[1] by the late Mr. W. Donkin, whose
+premature death among the Caucasus Mountains was deeply deplored
+by all. Those reproduced were kindly lent by his brother, Mr. A. E.
+Donkin, of Rugby. To Messrs. Valentine & Son of Dundee, Mr. Wilson
+of Aberdeen, and to Messrs. Frith we are indebted for permission to
+reproduce some of their admirable photographs; also to Messrs. James
+How & Sons of Farringdon Street, for three excellent photographs of
+rock-sections taken with the microscope.
+
+  [1] Published by Messrs. Spooner, of the Strand.
+
+
+
+
+CONTENTS.
+
+    Part I.
+
+    THE MOUNTAINS AS THEY ARE.
+
+    CHAPTER                                          PAGE
+
+    I. MOUNTAINS AND MEN                                3
+
+    II. THE USES OF MOUNTAINS                          33
+
+    III. SUNSHINE AND STORM ON THE MOUNTAINS           70
+
+    IV. MOUNTAIN PLANTS AND ANIMALS                   103
+
+
+    Part II.
+
+    CHAPTER                                          PAGE
+
+    HOW THE MOUNTAINS WERE MADE.
+
+    V. HOW THE MATERIALS WERE BROUGHT TOGETHER        139
+
+    VI. HOW THE MOUNTAINS WERE UPHEAVED               174
+
+    VII. HOW THE MOUNTAINS WERE CARVED OUT            205
+
+    VIII. VOLCANIC MOUNTAINS                          242
+
+    IX. MOUNTAIN ARCHITECTURE                         282
+
+    X. THE AGES OF MOUNTAINS AND OTHER QUESTIONS      318
+
+
+
+
+ILLUSTRATIONS.
+
+
+    NORHAM CASTLE. After Turner                   _Frontispiece_
+
+    BEN LOMOND. From a Photograph by J. Valentine             16
+
+    CLOUDS ON BEN NEVIS                                       38
+
+    SNOW ON THE HIGH ALPS. From a Photograph by
+        Mr. Donkin                                            64
+
+    A STORM ON THE LAKE OF THUN. After Turner                 86
+
+    THE MATTERHORN. From a Photograph by Mr. Donkin           98
+
+    ON A GLACIER.                                            116
+
+    RED DEER. After Ansdell                                  133
+
+    CHALK ROCKS, FLAMBOROUGH HEAD. From a Photograph by
+        G. W. Wilson                                         152
+
+    MICROPHOTOGRAPHS ILLUSTRATING ROCK FORMATION             172
+
+    THE SKAEGGEDALSFORS, NORWAY. From a Photograph by
+        J. Valentine                                         192
+
+    THE MER DE GLACE AND MONT BUET. From a Photograph
+        by Mr. Donkin                                        229
+
+    THE ERUPTION OF VESUVIUS IN 1872. From an
+        Instantaneous Photograph                             250
+
+    COLUMNAR BASALT AT CLAMSHELL CAVE, STAFFA. From
+        a Photograph by J. Valentine                         280
+
+    MONT BLANC, SNOWFIELDS, GLACIERS, AND STREAMS.           312
+
+    MOUNTAIN IN THE YOSEMITE VALLEY.                         336
+
+
+
+
+    ILLUSTRATIONS II.
+
+    Fig. 1. SECTION ACROSS THE WEALD OF KENT AND SURREY.     237
+
+    Fig. 2. THE HIGHLANDS OF SCOTLAND ON A TRUE
+    SCALE (after Geikie.)                                    237
+
+    Fig. 1. THE RANGES OF THE GREAT BASIN, WESTERN
+    STATES OF NORTH AMERICA, SHOWING A SERIES OF
+    GREAT FRACTURES AND TILTED MASSES OF ROCK.               272
+
+    Fig. 2. SECTION THROUGH SNOWDON.                         272
+
+    SECTIONS OF MOUNTAIN-RANGES, SHOWING THEIR
+    STRUCTURE AND THE AMOUNT OF ROCK WORN AWAY               306
+
+
+
+
+PART I.
+
+THE MOUNTAINS AS THEY ARE.
+
+
+
+
+THE STORY OF THE HILLS.
+
+Part I.
+
+THE MOUNTAINS AS THEY ARE.
+
+
+
+
+CHAPTER I.
+
+MOUNTAINS AND MEN.
+
+    "Happy, I said, whose home is here;
+    Fair fortunes to the Mountaineer."
+
+
+In old times people looked with awe upon the mountains, and
+regarded them with feelings akin to horror or dread. A very slight
+acquaintance with the classical writers of antiquity will suffice
+to convince any one that Greeks and Romans did so regard them. They
+were not so familiar with mountains as we are; for there were no
+roads through them, as now through the Alps, or the Highlands of
+Scotland,--to say nothing of the all-pervading railway. It would,
+however, be a great mistake to suppose that the ancients did not
+observe and enjoy the beauties of Nature. The fair and fertile
+plain, the vine-clad slopes of the lower hill-ranges, and the
+"many-twinkling smile of ocean" were seen and loved by all who had
+a mind to appreciate the beautiful. The poems of Homer and Virgil
+would alone be sufficient to prove this. But the higher ranges,
+untrodden by the foot of man, were gazed at, not with admiration,
+but with religious awe; for men looked upon mountains as the abode
+of the gods. They dwelt in the rich plain, which they cultivated,
+and beside the sweet waters of some river; for food and drink are
+the first necessities of life. But they left the high hills alone,
+and in fancy peopled them with the "Immortals" who ruled their
+destiny,--controlling also the winds and the lightning, the rain and
+the clouds, which seem to have their home among the mountains. A
+childlike fear of the unknown, coupled with religious awe, made them
+avoid the lofty and barren hills, from which little was to be got
+but wild honey and a scanty supply of game. There were also dangers
+to be encountered from the fury of the storm and the avalanche; but
+the safer ground of the plains below would reward their toil with an
+ample supply of corn and other necessaries of life.
+
+In classical times, and also in the Middle Ages, the mountains,
+as well as glens and rivers, were supposed to be peopled with
+fairies, nymphs, elves, and all sorts of strange beings; and even
+now travellers among the mountains of Switzerland, Norway, Wales,
+or Scotland find that it is not long since the simple folk of these
+regions believed in the existence of such beings, and attributed to
+their agency many things which they could not otherwise explain.
+
+Of all the nations of antiquity the Jews seem to have shown the
+greatest appreciation of mountain scenery; and in no ancient writings
+do we find so many or so eloquent allusions to the hills as in the
+Old Testament. But here again one cannot fail to trace the same
+feelings of religious awe. The Law was given to their forefathers
+in the desert amidst the thunders of Sinai. To them the earth was
+literally Jehovah's footstool, and the clouds were His tabernacle.
+"If He do but touch the hills, they shall smoke."
+
+But this awe was not unmixed with other and more comforting thoughts.
+They felt that those cloud-capped towers were symbols of strength and
+the abode of Him who would help them in their need. For so we find
+the psalmists regarding them; and with our very different conceptions
+of the earth's natural features, we can but dimly perceive and
+realise the full force and meaning of the words, "I will lift up mine
+eyes unto the hills, from whence cometh my help."
+
+To take another example from antiquity, we find that the Himalayas
+and the source of the Ganges have from very early times been
+considered as holy by the people of India. Thousands of pilgrims from
+all parts of that vast country still continue to seek salvation in
+the holy waters of the Ganges, and at its sacred sources in the snowy
+Himalayas. And to those who know India the wondrous snowclad peaks of
+the Himalayas still seem to be surrounded with somewhat of the same
+halo of glory as of old.
+
+Mountains are intimately associated with the history of nations, and
+have contributed much to the moulding of the human mind and the
+character of those who dwell among them; they have alike inspired the
+mind of the artist, the poet, the reformer, and the visionary seeking
+repose for his soul, that, dwelling far from the strife and turmoil
+of the world, he may contemplate alone the glory of the Eternal
+Being. They have been the refuge of the afflicted and the persecuted;
+they have braced the minds and bodies of heroes who have dwelt for a
+time among them before descending once more to the plain that they
+might play some noble part in the progress of the world.
+
+Moses, while leading the flock of his father-in-law to the back of
+the wilderness, came to Mount Horeb and received the divine summons
+to return to Egypt and lead Israel out of bondage. David, with his
+six hundred followers, fleeing from the face of Saul, found a refuge
+in the hill country; and the life of peril and adventure which he
+led during these years of persecution was a part of his training for
+the great future task of ruling Israel, which he performed so well.
+Elijah summoned the false prophets of Baal and Asherah to Mount
+Carmel and slew them at the brook Kishon; and a little later we find
+him at Mount Horeb listening, not to the wind or to the earthquake
+or to the fire, but to the "still small voice" telling him to return
+and anoint Jehu to be king.
+
+Or, to take another example from a later age, we find that Mahomet's
+favourite resort was a cave at the foot of Mount Hira, north of
+Mecca; here in dark and wild surroundings his mind was wrought up to
+rhapsodic enthusiasm.
+
+And many, like these leaders of men, have received in mountain
+retreats a firmness and tenacity of purpose giving them the right
+to be leaders, and the power to redress human wrongs; or, it may
+be, a temper of mind and spirit enabling them to soar into regions
+of thought and contemplation untrodden by the careless and more
+luxurious multitudes who dwell on the plains below. Perhaps Mr. Lewis
+Morris was unconsciously offering his testimony to the influence of
+mountains when he wrote those words which he puts into the mouth of
+poor Marsyas,--
+
+                        "More it is than ease,
+    Palace and pomp, honours and luxuries,
+    To have seen white presences upon the hills,
+    To have heard the voices of the eternal gods."[2]
+
+  [2] Epic of Hades.
+The thunder and lightning, storm and cloud, as well as the soft
+beauty of colour, and the harmony of mountain outline, have been a
+part, and a very important part, of their training. The exhilarating
+air, the struggle with the elements in their fierceness, the rugged
+strength of granite, seem to have possessed the very souls of such
+men, and made them like "the strong ones,"--the immortal beings to
+whom in all previous ages the races of mankind have assigned their
+abode in the hills, as the Greek gods were supposed to dwell on Mount
+Olympus. On these heights such men seem to have gained something of
+the strength of Him who dwells in the heavens far above their highest
+peaks,--"the strength of the hills," which, as the Hebrew poet says,
+"is His also."
+
+We have spoken of the attitude of the human mind towards mountains in
+the past; let us now consider the light in which they are regarded
+at the present time by all thoughtful and cultivated people. And it
+does not require a moment's consideration to perceive that a very
+great change has taken place. Instead of regarding them with horror
+or aversion, we look upon them with wonder and delight; we watch
+them hour by hour whenever for a brief season of holiday we take
+up our abode near or among them. We come back to them year by year
+to breathe once more the pure air which so frequently restores the
+invalid to health and brings back the colour to faded cheeks. We love
+to watch the ever-varying lights and shades upon them, as the day
+goes by. But it is towards evening that the most enchanting scenes
+are to be witnessed, when the sinking sun sheds its golden rays upon
+their slopes, or tinges their summits with floods of crimson light;
+and then presently, after the sun has gone down, pale mists begin
+to rise, and the hills seem more majestic than ever. Later on, as
+the full moon appears from behind a bank of cloud, those wonderful
+moonlight effects may be seen which must be familiar to all who know
+the mountains as they are in summer or autumn,--scenes such as the
+writer has frequently witnessed in the Highlands of Scotland, but
+which only the poet can adequately describe.
+
+There are few sights in Nature which more powerfully impress the mind
+than a sunset among the mountains. General Sir Richard Strachey
+concludes his description of the Himalayas with the following
+striking passage:
+
+   "Here may the eye, as it sweeps along the horizon, embrace a
+   line of snowclad mountains such as exist in no other part of
+   the world, stretching over one third of the entire circle,
+   at a distance of forty or fifty miles, their peaks towering
+   over a sea of intervening ranges piled one behind another,
+   whose extent on either hand is lost in the remote distance,
+   and of which the nearest rises from a gulf far down beneath
+   the spectator's feet, where may be seen the silver line that
+   marks a river's course, or crimson fields of amaranth and the
+   dwellings of man. Sole representative of animal life, some
+   great eagle floats high overhead in the pure dark-blue sky,
+   or, unused to man, fearlessly sweeps down within a few yards
+   to gaze at the stranger who intrudes among these solitudes of
+   Nature. As the sun sinks, the cold grey shadow of the summit
+   where we stand is thrown forward, slowly stealing over the
+   distant hills, and veiling their glowing purples as it goes,
+   carries the night up to the feet of the great snowy peaks,
+   which still rise radiant in the rosy light above the now
+   darkening world. From east to west in succession the splendour
+   fades away from one point after another, and the vast shadow of
+   the earth is rapidly drawn across the whole vault of heaven.
+   One more departing day is added to the countless series which
+   has silently witnessed the deathlike change that passes over
+   the eternal snows, as they are left raising their cold pale
+   fronts against the now leaden sky; till slowly with the
+   deepening night the world of mountains rises again, as it were,
+   to a new life, under the changed light of the thousand stars
+   which stud the firmament and shine with a brilliancy unknown
+   except in the clear rarefied air of these sublime heights."
+
+Year by year a larger number of busy workers from our great towns,
+availing themselves of the increased facilities for travel, come to
+the mountains to spend their summer holidays,--some to the Swiss
+Alps, others to Wales, Cumberland, Norway, or the Highlands of
+Scotland. There are few untrodden valleys in these regions, few of
+the more important mountains which have not been climbed.
+
+Our knowledge of mountains, thanks to the labours of a zealous army
+of workers, is now considerable. The professors of physical science
+have been busy making important observations on the condition of
+the atmosphere in the higher regions; geographers have noted their
+heights and mapped their leading contours. Geologists have done a
+vast amount of work in ascertaining the composition and arrangement
+of the rocks of which mountain chains are composed, in observing
+their peculiar structures, in recording the changes which are
+continually effecting their waste and decay, and thus interpreting
+the story of the hills as it is written in the very rocks of which
+they are built up.
+
+Naturalists have collected and noted the peculiar plants and animals
+which have their home among the hills, and so the forms of life, both
+animal and vegetable, which inhabit the mountains of Europe, and some
+other countries, are now fairly well known.
+
+The historian, the antiquary, and the student of languages have
+made interesting discoveries with regard to the mountain races of
+mankind. And only to mention this country, such writers as Scott,
+Wordsworth, and Ruskin have given us in verse and prose descriptions
+of mountain scenery which will take a permanent place in literature;
+while Turner, our great landscape-painter, has expressed the glories
+of mountain scenery in pictures which speak more eloquently than
+many words. Thus we see that whatever line of inquiry be chosen, our
+subject is full of varied interest.
+
+With regard to the characteristics of mountain races, it is not easy
+to say to what extent people in different parts of the world who
+live among mountains share the same virtues or the same failings;
+but the most obvious traits in the character of the mountaineer
+seem to be the result of his natural surroundings. Thus we find
+mountaineers generally endowed with hardihood, strength, and bravery.
+To spend one's days on the hillsides for a large part of the year, as
+shepherds and others do in Scotland or Wales, and to walk some miles
+every day in pure bracing air, must be healthy and tend to develop
+the muscles of the body; and so we find the highlanders of all
+countries are usually muscular, strong, and capable of endurance. And
+there can be little doubt that mountain races are kept up to a high
+standard of strength and endurance by a rigorous and constant weeding
+out of the weakly ones, especially among children. And if only the
+stronger live to grow up and become parents, the chances are that
+their children will be strong too. Thus Nature exercises a kind of
+"selection;" and we have consequently "the survival of the fittest."
+This "selection," together with the healthy lives they lead, is
+probably sufficient to account for their strength and hardiness.
+
+As might be expected, mountaineers are celebrated for their fighting
+qualities. The fierce Afghans who have often faced a British army,
+and sometimes victoriously; the brave Swiss peasantry, who have
+more than once fought nobly for freedom; the Highlanders, who have
+contributed so largely to the success of British arms in nearly
+all parts of the world, and whose forefathers defied even the
+all-conquering Roman in their mountain strongholds,--these and many
+others all show the same valour and power of endurance. Etymologists,
+whose learned researches into the meaning of words have thrown so
+much light on the ages before history was written, tell us that the
+Picts were so called from their fighting qualities, and that the
+word "Pict" is derived from the Gaelic "peicta," a fighting man. And
+Julius Cæsar says the chief god of the Britons was the god of war.
+
+In some countries--as, for instance, Greece, Italy, and Spain--the
+mountains are infested with banditti and robbers, who often become a
+terror to the neighbourhood. In more peaceful and orderly countries,
+however, we find among mountaineers many noble qualities,--such
+as patience, honesty, simplicity of life, thrift, a dignified
+self-reliance, together with true courtesy and hospitality. This is
+high praise; but who that knows mountain peasants would say it is
+undeserved? How many a tired traveller among the hills of Scotland
+or Wales has had reason to be grateful for welcome, food, and rest
+in some little cottage in a far-away glen! How many friendships have
+thus been formed! How many a pleasant talk has beguiled the time
+during a storm or shower! The old feuds are forgotten now that the
+Saxon stranger and invader is at peace with the Celtic people whom
+his forefathers drove into the hills. The castles, once centres of
+oppression or scenes of violence, lie in peaceful and picturesque
+ruins, and add not a little to the interest of one's travels in the
+North. What true courtesy and consideration one meets with at the
+hands of these honest folk, among whom the old kindly usages have
+not died out! Often too poor to be afflicted with the greed and
+thirst for wealth, which frequently marks the man of the plain as
+compared with the man of the hills,--the Lowlander as compared with
+the Highlander,--they exhibit many of those simple virtues which
+one hardly expects to meet with among busy townspeople, all bent on
+making money, or as the phrase is, "getting on in life."
+
+  [Illustration: BEN LOMOND. FROM A PHOTOGRAPH BY J. VALENTINE.]
+
+    "The mountain cheer, the frosty skies,
+    Breed purer wits, inventive eyes;
+    And then the moral of the place
+    Hints summits of heroic grace.
+    Men in these crags a fastness find
+    To fight corruption of the mind;
+    The insanity of towns to stem
+    With simpleness for stratagem."
+
+Mr. Skene, the Scotch historian, records a touching case of the
+devotion of Highlanders to their chief. He says,--
+
+   "There is perhaps no instance in which the attachment of the
+   clan to their chief was so strongly manifested as in the
+   case of the Macphersons of Cluny after the disaster of 'the
+   Forty-five.' The chief having been deeply engaged in that
+   insurrection, his life became of course forfeited to the laws;
+   but neither the hope of reward nor the fear of danger could
+   induce any one of his people to betray him. For nine years
+   he lived concealed in a cave a short distance from his own
+   house; it was situated in the front of a woody precipice of
+   which the trees and shelving rocks concealed the entrance. The
+   cave had been dug by his own people, who worked at night and
+   conveyed the stones and rubbish into a neighbouring lake, in
+   order that no vestige of their labour might appear and lead to
+   the discovery of the retreat. In this asylum he continued to
+   live secure, receiving by night the occasional visits of his
+   friends, and sometimes by day, when the soldiers had begun to
+   slacken the vigour of their pursuit. Upwards of one thousand
+   persons were privy to his concealment, and a reward of £1,000
+   was offered to any one who should give information against
+   him.... But although the soldiers were animated by the hope
+   of reward, and their officers by promise of promotion for
+   the apprehension of this proscribed individual, yet so true
+   were his people, so inflexibly strict in their promise of
+   secrecy, and so dextrous in conveying to him the necessaries he
+   required in his long confinement, not a trace of him could be
+   discovered, nor an individual base enough to give a hint to his
+   detriment."
+
+The mountaineer is a true gentleman. However poor, however ignorant
+or superstitious, one perceives in him a refinement of manner which
+cannot fail to command admiration. His readiness to share his
+best with the stranger and to render any service in his power are
+pleasing traits in his character. But there is one sad feature about
+mountaineers of the present day which one frequently notices in
+districts where many tourists come,--especially English or American.
+They are, we regret to say, losing their independence, their simple,
+old-fashioned ways, and becoming servile and greedy,--at least in the
+towns and villages. Such changes seem, alas! inevitable when rich
+townspeople, bent on pleasure or sport, invade the recesses of the
+hills where poverty usually reigns. On the one hand, we have people,
+often with long purses, eager for enjoyment, waiting to be fed,
+housed, or otherwise entertained; on the other hand, poor people,
+anxious to "make hay while the sun shines" and to extract as much
+money as possible from "the visitors," who often allow themselves
+to be unmercifully fleeced. Then there are in the Highlands the
+sportsmen, who require a large following of "gillies" to attend them
+in their wanderings, pay them highly for their services, and dismiss
+them at the end of the season; and so the men are in many cases left
+without employment all the winter and spring. Is it, then, surprising
+that they give way to a natural tendency to idleness, and fall into
+other bad habits? Any visitor who spends a winter, or part of one,
+in the Highlands will be better able to realise the extent of this
+evil, which is by no means small; and one cannot help regretting that
+the sportsmen's pleasure and the tourist's holiday should involve
+results of such grave consequence. We are inclined to think that in
+these days sport is overdone, and wish it could be followed without
+taking the hillman away from the work he would otherwise find, and
+which would render him a more useful member of society. With the
+agitation going on in some parts against deer-forests we do not
+feel much sympathy, because they are based on the erroneous idea
+that "crofters" could make a living out of the land thus enclosed;
+whereas those who know the land and its value for agricultural
+purposes tell us that with the exception of a few small patches here
+and there, hardly worth mentioning, it could not possibly be made to
+produce enough to maintain crofters and their families. Nevertheless,
+another way of looking at the matter is this: that the man who merely
+ministers to the pleasure of others richer than himself loses some of
+the self-respect and independence which he would acquire by working
+in his own way for a living.
+
+The same changes for the worse are still more manifest in
+Switzerland; and even in some parts of Norway the people are being
+similarly spoiled. Mr. Ruskin, speaking of the former country, says:
+
+   "I believe that every franc now spent by travellers among
+   the Alps tends more or less to the undermining of whatever
+   special greatness there is in the Swiss character; and the
+   persons I met in Switzerland whose position and modes of life
+   render them best able to give me true information respecting
+   the present state of their country, among many causes of
+   national deterioration, spoke with chief fear of the influx
+   of English wealth, gradually connecting all industry with the
+   wants of strangers, and inviting all idleness to depend upon
+   their casual help, thus resolving the ancient consistency and
+   pastoral simplicity of the mountain life into the two irregular
+   trades of the innkeeper and mendicant."[3]
+
+  [3] Modern Painters, vol. iv.
+
+Mountain people have still their superstitions; since the
+introduction of railways many of the old legends and popular myths
+have died out, but even what is left is interesting to the student of
+folk-lore,--indeed, we might say, to every one.
+
+Sir A. Geikie, speaking of Scotch mountain scenery says,--
+
+    "To the influence of scenery of this kind on the mind of a
+   people at once observant and imaginative, such legends as that
+   of the Titans should in all likelihood be ascribed. It would be
+   interesting to trace back these legends to their cradle, and to
+   mark how much they owe to the character of the scenery amongst
+   which they took their rise. Perhaps it would be found that the
+   rugged outlines of the Boeotian hills had no small share in
+   the framing of Hesiod's graphic story of that primeval warfare
+   wherein the combatants fought with huge rocks, which, darkening
+   the air as they flew, at last buried the discomfited Titans
+   deep beneath the surface of the land. Nor would it be difficult
+   to trace a close connection between the present scenery of our
+   own country and some of the time-honoured traditionary stories
+   of giants and hero kings, warlocks and witches, or between the
+   doings of the Scandinavian Hrimthursar, or Frost Giants, and
+   the more characteristic features of the landscapes and climate
+   of the North."[4]
+
+  [4] Scenery of Scotland.
+
+The following passage from Ruskin brings out more strongly the
+effects of mountains on men,--a subject to which he has given much
+attention:--
+
+   "We shall find, on the one hand, the mountains of Greece and
+   Italy, forming all the loveliest dreams, first of Pagan, then
+   of Christian mythology, on the other, those of Scandinavia, to
+   be the first sources of whatever mental (as well as military)
+   power was brought by the Normans into Southern Europe. Normandy
+   itself is, to all intents and purposes, a hill country.... We
+   have thus one branch of the Northern religious imagination
+   rising among the Scandinavian fiords, tempered in France
+   by various encounters with elements of Arabian, Italian,
+   Provençal, or other Southern poetry, and then reacting upon
+   Southern England; while other forms of the same rude religious
+   imagination, resting like clouds upon the mountains of Scotland
+   and Wales, met and mingled with the Norman Christianity,
+   retaining even to the latest times some dark colour of
+   superstition, but giving all its poetical and military pathos
+   to Scottish poetry, and a peculiar sternness and wildness of
+   tone to the Reformed faith, in its manifestations among the
+   Scottish hills."[5]
+
+  [5] Modern Painters, vol. iv.
+
+The Alps, like most other mountainous countries, have their fair
+share of legends, some of which are very grotesque. We have selected
+the following, as related by Professor Bonney.[6] The wild huntsman's
+yell is still heard in many places by the shuddering peasants as his
+phantom train sweeps by the châlet. There is also the wild goat-herd,
+a wicked lad, who crucified an old he-goat and drove his flock to
+worship it; lightning consumed him; and now he wanders forever over
+the Alps, miserably wailing.
+
+  [6] "The Alpine Regions of Switzerland" (Deighton, Bell, & Co.),
+  a most interesting book, especially for travellers.
+
+When the glacier of Gétroz burst, the Archfiend himself was seen
+swimming down the Rhone, with a drawn sword in one hand and a golden
+ball in the other; when opposite to Martigny he halted, and at his
+bidding the waters rose and swept away part of the town. A vast
+multitude of imps was seen about the same time on a mountain in the
+Val de Bagnes by two mendicant friars from Sion, who, hearing of this
+unlawful assembly, had gone out as detectives to learn what mischief
+was hatching.
+
+Many places also have their spectral animals, the Valois, according
+to Tschudi, being the headquarters of these legends. There are also
+pygmies to be seen in the lonely mountains, like the Norwegian
+trolls, and brownies who make or mar the house, according as the
+goodwife is neat or a slattern.
+
+Many Alpine stories have reference to the sudden destruction of
+pastures by the fall of rocks or ice. Here is one from the Clariden
+Alps:--
+
+   Once upon a time these were fertile pastures, on which dwelt a
+   "senn." He grew rich, so that none could match him in wealth;
+   but at the same time he grew proud and haughty, and spurned
+   both the laws of Nature and the commandments of God. He was
+   so foolishly fond of his mistress that he paved the way from
+   the châlet to the byre with cheeses, lest she should soil her
+   feet, and cared so little for his mother that when she lay at
+   his door fainting with hunger, he offered her only milk to
+   drink in which he had thrown the foulest refuse. Righteously
+   indignant, she turned away, calling upon Heaven to punish such
+   an insult. Before she reached her home, the rocks and ice had
+   descended, crushing beneath them her wicked son, his mistress,
+   and possessions.
+
+   In the neighbourhood of Monte Rosa there is a tradition that
+   a valley exists in the heart of that mountain the entrance to
+   which has been sealed up by impassable glaciers, though the
+   floor of the "cirque" within is still a rich pasturage. In a
+   certain valley they point out a spring which bursts from the
+   ground, as the outlet of the torrent by which it is watered.
+   Once, said they, a _chasseur_ found the bed of this stream dry,
+   and creeping up its subterranean channel, arrived on the floor
+   of the valley. It was a huntsman's paradise; chamois were there
+   in plenty, bears also, and even bouquetins, wandering over the
+   richest pastures. He retraced his steps to announce the good
+   news; but when he returned again, the waters had resumed their
+   course, and the place has ever since remained inaccessible.
+
+Mountains play a very important part in human history. In the first
+place, they are natural barriers separating the nations of the
+world from one another, and tending to keep them confined within
+certain definite bounds; we say, tending to keep them thus confined,
+because, as every one knows, these barriers have again and again been
+surmounted by conquering armies. The rugged Alps could not ward off
+Hannibal, who made his way through them to march upon the capital of
+the Roman empire. In like manner Napoleon defied this great natural
+rampart, made a road through it, and came to Italy. No mountains
+would seem to be quite impassable; but although liable in the course
+of ages to be occasionally overrun, they afford good protection and
+produce a feeling of security.
+
+The Himalayas separate our great Indian empire from that of China;
+and we do not at present apprehend an invasion from that quarter.
+The Suliman Mountains divide us from the Afghans, and the great
+Russian and Persian empires farther west. Still, we know that in the
+eleventh century a great Mahometan invasion of India took place;
+our own armies have more than once penetrated to Kabul. Perhaps the
+common garden wall separating adjacent suburban residences furnishes
+a suitable illustration of the great natural walls which divide, not
+households or families, but much larger families than these,--the
+nations of the world.
+
+Just as unruly boys sometimes climb over the neighbour's wall and
+play games in a garden which is not their own; or as burglars may
+surmount these obstacles to their progress, and finding a way
+into the house by a back door or kitchen window, commence their
+ravages,--so a neighbouring (but not neighbourly) nation, bent on
+conquest, may invade some natural garden of the world, such as
+India, by forcing their way through physical barriers which for
+ordinary purposes serve to protect those within.
+
+The Thian Shan Mountains divide Russia from China's sphere of
+influence. The Caucasus Mountains separate Russia from Asia Minor.
+Austro-Hungary is bounded by the Carpathians, Spain by the Pyrenees.
+The Alps of Switzerland separate four nations not very friendly
+to each other; and lastly, in our own country the Cheviot Hills,
+together with the Tweed, form the boundary between Scotland and
+England.
+
+Where there are no mountains or hills, rivers sometimes serve as
+boundaries, but of course they do not answer the purpose so well.
+Sometimes a nation actually builds a wall for a boundary. Of this the
+great wall of China and the Roman wall between the Cheviots and the
+Solway Firth are familiar examples.
+
+In the second place, mountains have always been a refuge and shelter
+for conquered races; and the primitive tribes who once lived in the
+plains have been forced by adverse circumstances to take to the
+hills. This has taken place over and over again.
+
+We know that the Celtic people now living in Brittany, Devonshire,
+Cornwall, Wales, Scotland, and Ireland, though now considerably
+mixed, are the descendants of the old Celtic inhabitants of France
+and Britain. But there is a great deal of unwritten history for which
+we may look in vain to the ordinary sources of information, such as
+books, and which is only to be read in quite different records,--in
+antiquities buried up in peat-beds, in bogs, in ruins and ancient
+forts, or camps; and last but not least, in the names of places,
+rivers, or mountains. The hills, the valleys, the rivers, are the
+only writing-tablets on which unlettered nations have been able to
+inscribe their annals. For this kind of history we must go to the
+antiquary, and, above all, to the philologist, who tells us the
+meaning of the names of places, and who the people were who gave the
+names that we see on our maps. The great advances which have of late
+years been made in our knowledge of the primeval races of men, or
+at least of nations but little known in the annals of history, are
+largely due to the interpretation of the obscure records preserved in
+local names. The Celtic, the Iberian, the Teutonic, the Scandinavian,
+and Sclavonic races have thus for the most part made known to us
+their migrations, conquests, and defeats. And so by studying the
+names of places, rivers, and hills, as well as by careful collection
+of works of art, implements, coins, such as may be seen in many a
+museum, it has been possible to read a great deal of early history
+which would otherwise have been lost.
+
+Those who have studied these matters say they can trace wave after
+wave of population which has thus left its mark,--Gaelic, Cymric (or
+Welsh), Saxon, Anglian, Norwegian, Danish, Norman, and Flemish. Thus
+it can be proved from the names on the map that almost the whole of
+England was once Celtic, whereas now the Celts are almost entirely
+confined to the hills. The Peak of Derbyshire and the mountains of
+Cumberland retain a greater number of Celtic names than the districts
+surrounding them; and the hills of Devonshire long served as a
+barrier to protect the Celts of Cornwall from Anglo-Saxon conquerors.
+
+But even mountain races are often a good deal mixed, and in the
+Pyrenees we find the descendants of the Iberians, who, a very long
+time ago, were driven from the lowlands of France and Spain. These
+Iberians are a very interesting race, of short stature, with long
+heads, and dark hair and eyes. This old type is to be met with in
+Wales and the Highlands even in the present day. And so we learn--if
+these conclusions are sound--that even the Celts in their early days
+were invaders, and drove before them an older population. This race,
+it seems, lived in Europe a very long time ago, before the discovery
+of metals, when people made axes, hammers, and spear-heads out of
+flints or other stones; and so they are said to belong to "the Stone
+Age." Their remains are found in many of the caves which of late
+years have been explored. Possibly the ancient people of Switzerland
+who lived in wooden houses, erected on piles near the shores of lakes
+(probably for safety), were also of the same stock.
+
+It is curious to find how people living in separate valleys among the
+mountains of Switzerland have, in the course of time, become so much
+unlike their neighbours that they can hardly understand each other's
+speech, so effectually have the mountains kept them apart. In some
+districts almost every valley has its separate dialect. Switzerland
+is only twice the size of Wales, yet the local names are derived
+from half a dozen different languages, three or four of which are
+still spoken by the people. In the Alps, too, the same mixture of
+Celtic with an older Iberian stock has been detected.
+
+A curious reversal of the usual order of things is noticed by the
+late Dean Stanley in his "Sinai and Palestine." He points out that
+the Jews took possession of many of the hills of Palestine soon after
+the invasion under Joshua, but could not drive out the peoples of the
+plains, because they were better armed, and had chariots of iron in
+great number. The conquerors in this case kept to the hills; while
+the Canaanites, Philistines, and other inhabitants of the country
+retained for a long time their hold of the lower ground.
+
+
+
+
+CHAPTER II.
+
+THE USES OF MOUNTAINS.
+
+   The valleys only feed; the mountains feed and guard and
+   strengthen us.--RUSKIN.
+
+
+It is not an exaggeration to say that there are no physical
+features of the surface of the earth which render such a variety of
+services as mountains. The operations which they perform involve
+such far-reaching consequences that it is difficult to say where
+their effects cease. Indeed, it might almost be maintained that
+they are the mainspring of the world,--as far as its surface is
+concerned,--for it would fare ill with mankind if they were removed
+or in some way destroyed. Things would then very soon come to a
+standstill. The soil would become exhausted; streams would cease to
+flow; and the world would become a kind of stagnant pool.
+
+The three main services of the hills are these:--
+
+   I. Mountains help to condense water-vapour from the atmosphere,
+   thus bringing back to the earth moisture which it loses
+   continually by evaporation.
+
+   II. Mountains are elevated reservoirs of water in one form or
+   another, and thus not only feed the streams and rivers, but
+   give them force and direction as well.
+
+   III. Mountains suffer themselves to be slowly worn away in
+   order that the face of the earth may be renewed; in other
+   words, they die that we, and all created things, may live.
+
+
+I. _Mountains help to condense water-vapour from the atmosphere, thus
+bringing back to the earth the moisture which it loses continually by
+evaporation._ Every one knows that there is abundance of water-vapour
+in the atmosphere, but the question arises, How does it get there?
+The answer to this lies in the simple fact that every surface of
+water exposed to the air undergoes loss by evaporation. If you wish
+to satisfy yourself on this point, place a saucer of water in your
+room, and in a few days it will all be gone. We hang clothes out to
+dry, and so avail ourselves of this curious power that air has of
+taking up water in the form of vapour. Steam, or water-vapour, is
+really invisible, though we frequently talk of seeing the steam
+issuing from a locomotive; but what we really see is a cloud of
+condensed steam, and such clouds,[7] like those that we see floating
+in the air, are really masses of little tiny particles of water which
+can reflect or throw back the light which falls upon them, and thus
+they become visible. Again, a kettle of water, if left too long on
+the fire will entirely boil away. It is all turned into steam, and
+the steam is somehow hidden away in the air, though a little of it
+will be condensed into slight clouds by the colder air outside the
+kettle.
+
+  [7] It has lately been proved that clouds can only form in air
+  which contains dust, and that each little suspended particle of
+  water contains a speck of dust or a tiny germ of some sort for
+  its nucleus.
+
+But how can water stow itself away in the air without being seen or
+felt?
+
+An illustration may help to explain this. Suppose you scatter a
+spoonful of small shot over a carpet or a dark-coloured table-cloth;
+you would probably not be able to see them at a little distance.
+Now, gather them together in a heap, and you see them at once. The
+heap of shot in some ways resembles a drop of water, for in a drop
+of water the tiny particles (or molecules) of which it is composed
+are close together; but by heating water you cause them to fly
+asunder and scatter themselves in various directions. They are lost
+to sight, and moreover have no power of attracting each other or of
+acting in concert; each one then takes its own course, whereas in
+the drop of water they were in some wonderful way bound together by
+mutual attraction. They dance in groups; but the rude force of heat
+will scatter these little dancing groups, and break them up into that
+state which we call a state of vapour.
+
+The forces of heat and cohesion are directly at variance; and it
+is just a question of degree whether the one or the other gets the
+mastery in this "tug of war." The more you heat the water, the faster
+the little groups of molecules break up and disappear in the air.
+They must in some way go moving between the particles of air, and
+collisions keep taking place with inconceivable rapidity.
+
+And now another question arises; namely, how much water-vapour can
+the air take? That depends chiefly on its temperature. Air when
+heated will take up a great deal of steam; and the more you heat air,
+the more it can take up. When air at a given temperature can take up
+no more, it is said to be saturated for that temperature; but if the
+temperature be raised, it will immediately begin to take up more. For
+each degree of temperature there is a certain amount of water-vapour
+which can be absorbed, and no more. But suppose we take some air
+which is already saturated and lower its temperature by giving it
+a sudden chill, what will happen? It will immediately give up part
+of its steam, or water-vapour; namely, the exact amount which it is
+unable to contain at the lower temperature.[8]
+
+  [8] Pressure also has an important influence, but was omitted
+  above for the sake of simplicity.
+
+There are various ways in which you can test this matter for
+yourself. For instance, take a hand-glass, and breathe on it. You
+know what will happen: a film of moisture forms upon it; and you know
+the reason why. It is simply that the cold glass gives a chill to
+one's breath (which being warm is highly charged with water-vapour
+from the lungs), and so some of the vapour is at once condensed. Now,
+this serves very well to explain how mountains catch water-vapour,
+and condense it. They are, as it were, a cold looking-glass; and
+the hot breath of the plains, as it strikes their sides, receiving
+a sudden chill, throws down part of the vapour it contains. On the
+higher parts of mountain-ranges the cold is so great that the water
+assumes the form of snow.
+
+Mountains, as every one knows, are colder than the plains below.
+No one cares to stay very long on a mountain-top, for fear of
+catching cold. It may be worth while to consider why they are cold.
+Perhaps you answer, "Because they are so high." That is true, but
+not a complete answer to our question. We must look at the matter a
+little more closely. The earth is a warm body surrounded by space in
+which the cold is inconceivably intense; but just as we protect our
+bodies against cold with garments, so the earth is wrapped up in an
+atmosphere which serves more or less to keep in the heat. All warm
+bodies give out heat as luminous bodies give out light; but the rays
+of heat, unlike those of light, are quite invisible to our eyes, so
+that we are unaware of them. These "dark heat-rays," as they are
+called, do not make any impression on the retina, because our eyes
+are not capable of responding to them as they do to the ordinary rays
+of light. But there is a delicate little instrument known as the
+thermopile, which responds to, and so detects these invisible rays;
+and if our eyes were sensitive to such vibrations as these, we should
+see heat-rays (which like light and sound are due to vibrations)
+streaming from every object, just as light does from a candle-flame.
+
+Those parts of the earth which are least covered or protected by the
+atmosphere lose heat most rapidly,--in the same way that on a frosty
+day one's fingers become cold unless covered up. Now, there is less
+air over mountains; and in those higher regions above the peaks
+what air there is, is more rarefied, and therefore less capable of
+stopping the heat-rays coming from the earth. Professor Tyndall has
+shown that water-vapour in the air has a great power of stopping dark
+heat-rays; and the lower regions, which contain more vapour, stop or
+absorb a good deal of heat which would otherwise escape into space.
+
+Look at a map of any continent, and you will see the rivers streaming
+away from the mountains. All those vast quantities of water come
+from the atmosphere; and mountains do a large share of the work of
+condensing it from the state of vapour to that of water. Take the
+map of India, and look at the great range of the Himalayas. At
+their feet is the hot valley of the Ganges, which meets that of the
+Brahmapootra River. An immense amount of evaporation takes place
+from these mighty rivers, so that the air above them becomes laden
+with water-vapour. Farther south is the tropical Indian Ocean, from
+which the direct rays of the sun draw up still vaster quantities of
+water. And so when south winds blow over India, they are full of
+water-vapour; and presently they strike the flanks of the Himalayas,
+and at once they are chilled, and consequently part with a large
+amount of the vapour which they contained. This is best illustrated
+by the case of the southwest monsoon wind of the summer season, which
+sets in during the month of April, and continues to blow steadily
+towards the northeast till October. After leaving the Bay of Bengal,
+this warm wind, laden with vapour, meets ere long with the range
+known as the Khasi Hills, and consequently throws down a large part
+of its vapour in the form of rain. The rainfall here in the summer
+season reaches the prodigious total of five hundred inches, or about
+twenty times as much as falls in London during a whole year. After
+passing over these hills, the monsoon wind presently reaches the
+Himalayas; and another downpour then takes place, until by the time
+it reaches the wide plains of Thibet, so much water has been given up
+that it becomes a very dry wind instead of a moist one.
+
+It must not be supposed, however, that the condensation effected by
+mountains is entirely due to this coldness. They have another simple
+and effective way of compelling the winds to give up rain: their
+sloping sides force the winds which strike them to ascend into higher
+regions,--wedging them up as waves run up a sloping stony bank on the
+seashore,--and when the winds reach higher regions of the atmosphere
+they must (as explained above) suffer loss of heat, or in other
+words, have their temperature lowered. They also expand considerably
+as they rise into regions where the atmospheric pressure is less;
+and as every gas or vapour loses heat in the act of expansion, they
+undergo a further cooling from this cause also.
+
+We have now learned that the cooling process is brought about in
+three different ways: (1) By contact with the cold body of the
+mountains; (2) By giving out heat into space; (3) By expansion of
+the air as it reaches into the higher regions of the atmosphere.
+The "cloud-caps" on certain mountains and promontories are to be
+explained by all these causes combined.
+
+The west coast of Great Britain illustrates the same thing on a
+smaller scale. There the warm waters of the Gulf Stream, travelling
+in a northeasterly direction straight away from the Gulf of Mexico,
+strike the west coast of Ireland, England, and Scotland; and as most
+people are aware, the mild climate of Great Britain is chiefly due
+to this fact. If you contrast for a moment the east and west coasts
+of Britain, you will see that the latter is much more rocky and
+mountainous than the east coast. Mountains run down nearly all our
+western coasts. Now, it is this elevated and rocky side of Britain
+which catches most of the rain. Very instructive it is to compare the
+annual rainfall in different parts of Britain. On Dartmoor about 86
+inches of rain fall every year, while in London only about 24 inches
+fall annually; but then London has no range of mountains near, and is
+far away from the west coast. Again, while people in Ambleside have
+to put up with 78 inches of rain, in Norfolk they are content with
+the modest allowance of 24 inches or so. At a place called Quoich on
+the west coast of Scotland, about 117 inches fall every year. These
+differences are chiefly due to the different contour of the land down
+the west side of Britain, which is mountainous, while the east side
+is flat, and also to the fact that while easterly winds, which have
+come over the continent, are dry, our prevailing winds are from the
+west and southwest, and are consequently heavily laden with vapour
+from the Atlantic Ocean. These winds follow the direction of the Gulf
+Stream, driving it along before them; and in so doing they take up
+large quantities of vapour from its surface. When these warm winds
+touch our western coasts, they receive a chill, and consequently are
+no longer able to contain all the vapour which they bring with them,
+and so down comes the rain.
+
+
+II. _Mountains are elevated reservoirs of water in one form or
+another, and thus not only feed the streams and rivers, but give them
+force and direction as well._ It is very important that the mountains
+should not allow the waters they collect to run away too fast. Try
+to think for a moment what would happen if instead of being, as it
+were, locked up in the form of snowfields and glaciers, the water
+were all in the liquid form. It would soon run away, and for months
+together the great river-valleys would be dry and desolate. When the
+rain came, there would be tremendous floods; dire destruction would
+be wrought in the valleys; and very soon the great rivers would
+dwindle down to nothing. Vegetation too would suffer seriously for
+want of water during the summer months; and the valleys generally
+would cease to be the fertile sources of life which they are at
+present. The earth would become for the most part like a stagnant
+marsh.
+
+But in the higher mountain regions there is a beneficent process
+going on which averts such an evil. The precious supplies of water
+are stored up in the solid forms of snow and ice. Now, we all know
+that snow and ice take a long time to melt; and thus Nature regulates
+and like a prudent housewife economises her precious stores. The
+rivers which she feeds continually, from silent snowfields and
+glaciers among her mountain-peaks, are the very arteries and veins
+of the earth; and as the blood in our bodies is forced to circulate
+by pressure from the heart, so the rivers are compelled to flow by
+pressure from the great heart of the hills,--slow, steady, continuous
+pressure, not the quick pulses which the human heart sends through
+the body.
+
+And again, as the blood, after circulating through the body in an
+infinite number of life-giving streams, returns to the heart once
+more on its journey, so the thousand streams which wander over the
+plains find their way back to the heart of the mountains, for the
+water is brought there in the form of vapour and clouds by the winds.
+
+When we build water-towers, and make reservoirs on high ground to
+give pressure to the water in our pipes, and make it circulate
+everywhere,--even to the tops of our houses,--we are only taking a
+hint from Nature. The mountains are her water-towers, and from these
+strong reservoirs, which never burst, she commands her streams,
+forcing them along their courses in order that they may find their
+way to the utmost bounds of continents.
+
+But there is another way in which mountains regulate the supply
+of water, and prevent it from running away too fast,--one not so
+effective as the freezing process, but still very useful, because it
+applies to the lower hills below the line of perpetual snow. This may
+be well illustrated by the state of some of the Scotch hills in the
+middle of summer or autumn, when there is little if any snow resting
+upon them.
+
+Any one familiar with these hills will have noticed how full of
+water their sides are. Tiny threads of streams trickle slowly along
+everywhere; peat-beds are saturated with dark-brown water; even the
+grass and soil are generally more or less wet, especially under pine
+forests. One can generally get a cup of water somewhere, except
+after a long dry summer, which is exceptional. Then there is the dew
+forming every night. Forests with their undergrowth of soil--moss
+and fern--also help very considerably to check the flow of water. We
+have often asked ourselves when watching some swift-flowing river,
+"Where does all this water come from? Why does it not dry up in
+hot weather?" The answer came fully after we had climbed several
+mountains, and seen with our eyes the peat-beds among the hills, and
+heard the trickling of the tiny rivulets hurrying along to feed
+some neighbouring burn, or perhaps to run into some mountain tarn or
+loch, and noticed the damp, spongy state of the soil everywhere,--not
+to mention the little springs which here and there well up to the
+surface, and so contribute their share.
+
+The rivers and streams of Scotland assume various tints of amber
+and dark-brown, according to the amount of rain which has recently
+fallen. These colours are due to organic matter from the peat.
+Compare Scott's description of the Greta:--
+
+    "In yellow light her currents shone,
+    Matching in hue the favourite gem
+    Of Albion's mountain diadem."
+
+The waters of some Scotch rivers after heavy rain look as black as
+pitch.
+
+Nor must we omit the lakes which abound in most mountain regions,
+and serve as natural reservoirs for the rivers, besides giving a
+wonderful charm to mountain scenery.
+
+The largest lakes in mountainous regions are found on the courses
+of the rivers; and there is good reason to believe that they were
+formed, not by any process of subsidence, but by the same operations
+that carved out the valleys. In many cases they are due to the
+damming up of a stream. But in some countries the streams dry up
+during summer,--in Palestine or Sinai, where there is but little soil
+on the hills, and consequently hardly any vegetation. Such barren
+hills cannot hold the continual supplies which pour gently forth from
+the mountains of higher latitudes.
+
+The Alps feed four of the principal rivers of Europe. We cannot do
+better than quote Professor Bonney, whose writings on the Alps are
+familiar to all geologists. In his "Alpine Regions of Switzerland"
+the following passage occurs:--
+
+   "This mass of mountains, the great highlands of Europe, is
+   therefore of the utmost physical and geographical importance.
+   Rising in places to a height of more than fifteen thousand
+   feet above the sea, and covered for an extent of many thousand
+   square miles with perpetual snow, it is the chief feeder of
+   four of the principal rivers in Europe,--the Po, the Rhone,
+   the Rhine, and the Danube. But for those barren fields of ice,
+   high up among the silent crags, the seeming home of winter and
+   death, these great arteries of life would every summer dwindle
+   down to paltry streams, feebly wandering over stone-strewn
+   beds. Stand, for example, on some mountain-spur, and look down
+   on the Lombardy plain, all one rich carpet of wheat and maize,
+   of rice and vine; the life of those myriad threads of green
+   and gold is fed from these icy peaks, which stand out against
+   the northern sky in such strange and solemn contrast. As it is
+   with the Po, so it is with the Rhine and the Rhone, both of
+   which issue from the Alps as broad, swelling streams; so, too,
+   with the Danube, which, although it does not rise in them, yet
+   receives from the Inn and the Drave almost all the drainage of
+   the eastern districts."
+
+A very little reflection will serve to convince any one how vastly
+important and beneficial is the slope of the mountains, and how it
+gives force and direction to streams and rivers. Without this force,
+due to universal gravitation, by which the waters seek continually
+lower levels, the supplies in the hills would be useless. Mere lakes
+on flat surfaces would not answer the purpose; and so the sources of
+water are elevated in order that it may pour over the world below.
+
+No writer has given such fascinating descriptions of mountains as
+Mr. Ruskin; and no one has more eloquently described the functions
+they perform. In the fourth volume of his "Modern Painters," which
+every one who cares for mountains should read, we find the following
+beautiful passage:--
+
+   "Every fountain and river, from the inch-deep streamlet that
+   crosses the village lane in trembling clearness, to the massy
+   and silent march of the everlasting multitude of waters in
+   Amazon or Ganges, owe their play and purity and power to the
+   ordained elevations of the earth. Gentle or steep, extended
+   or abrupt, some determined slope of the earth's surface is of
+   course necessary before any wave can so much as overtake one
+   sedge in its pilgrimage; and how seldom do we enough consider,
+   as we walk beside the margins of our pleasant brooks, how
+   beautiful and wonderful is that ordinance, of which every
+   blade of grass that waves in their clear waters is a perpetual
+   sign,--that the dew and rain fallen on the face of the earth
+   shall find no resting-place; shall find, on the contrary,
+   fixed channels traced for them from the ravines of the central
+   crests down which they roar in sudden ranks of foam to the dark
+   hollows beneath the banks of lowland pasture, round which they
+   must circle slowly among the stems and beneath the leaves of
+   the lilies; paths prepared for them by which, at some appointed
+   rate of journey, they must evermore descend, sometimes slow,
+   and sometimes swift, but never pausing; the daily portion of
+   the earth they have to glide over marked for them at each
+   successive sunrise; the place which has known them knowing
+   them no more; and the gateways of guarding mountains opened for
+   them in cleft and chasm, none letting them in their pilgrimage,
+   and from afar off the great heart of the sea calling them to
+   itself: 'Deep calleth unto deep.'"
+
+Geologists, however, do not in these days teach that the present
+paths of rivers were made for them, but rather that the rivers have
+carved out their own valleys for themselves. The old teaching before
+the days of Lyell and Hutton, the founders of modern geology, was
+that valleys were rents in the rocks of the earth's crust formed
+by some wonderful convulsion of Nature, whereby they were cracked,
+torn asunder, and upheaved. But a careful study of rivers and their
+valleys for many years has shown that there is no evidence of such
+sudden convulsions. The world is very old indeed, and rivers have
+been flowing much as we see them for ages and ages. A few thousand
+years is to the geologist but a short space of time; and there can be
+no doubt that a stream can in the course of time carve out for itself
+a valley. The operations of Nature seem slow to us because our lives
+are so short, and we can see so little change even in a generation;
+but the effects of these changes mount up enormously when continued
+through a long space of time. Nature works slowly; but then she has
+unlimited time, and never seems in a hurry. It is like the old story
+of the hare and the tortoise; and the river, working on steadily and
+quietly for hundreds or thousands of years, accomplishes far more in
+the end than sudden floods or violent catastrophes of any sort.
+
+
+III. _Mountains suffer themselves to be slowly worn away in order
+that the face of the earth may be renewed; in other words, they die
+that we, and all created things, may live._ The reader will find a
+full account of the methods by which these results are accomplished
+in chapters v. and vii., and therefore we must not anticipate this
+part of the subject. Let it suffice for the present to say that
+this destruction of the hills is brought about by the action of
+heat and cold, of rain and frost, of snow and ice, and the thousand
+streams that flow down the mountain-sides. It is with soils that we
+are chiefly concerned at present. Try to think for a moment of the
+literally _vital_ consequences which follow from the presence of
+good rich soils over different parts of the earth, and ask whether
+it would be possible for civilised races of men to flourish and
+multiply as they do if it were not for the great fertile valleys and
+plains of the world. Mountain races are neither rich nor powerful.
+Man exists mainly by cultivation of the soil; and among mountains
+we only find here and there patches that are worthy of the labour
+and expenditure of capital involved in cultivation. But in the great
+plains, in the principal river-valleys of the world, and among the
+lesser hill-ranges it is different. The _lowlands_ are the fertile
+regions. All great and powerful nations of the world are children
+of the plains. It was so in the past; it will be so in the future,
+unless men learn to feed on something else than corn, milk, and
+flesh, which is not very likely.
+
+The Egyptians, the earliest civilised race of which we have
+satisfactory records, dwelt in the fertile valley and delta of
+the Nile. They clearly perceived the value of this great river to
+themselves, and worshipped it accordingly. They knew nothing of its
+source in the far-away lakes of Central Africa; but they knew truly,
+as Herodotus tells us, that Egypt was "the gift of the Nile," for the
+alluvial soil of its delta has been formed by the yearly floods of
+that great river, as its waters, laden with a fine rich mud, spread
+over its banks, and for a time filled the valley with one sheet of
+water. The Assyrians and Babylonians had their home in the valley of
+the Euphrates and Tigris. The Chinese, too, have their great rivers.
+Russia is well watered by powerful rivers. The most populous parts of
+the United States of America are watered by the great Mississippi,
+and the other rivers which flow into it. England, Germany, and France
+are furnished with well-watered plains.
+
+Soils are the chief form of national wealth. Minerals, such as coal
+and iron, are of course extremely valuable, and help to make an
+industrious race rich; but the land is the main thing, after all, and
+by land we mean soil. The two words are almost synonymous. But since
+the soil is formed chiefly of débris brought from the mountains, it
+would be more true to say that these are the real sources of wealth.
+Soils contain besides a large amount of valuable organic matter (that
+is, decayed matter which has once had animal or vegetable life)
+different kinds of minerals, which are necessary to the support of
+plant life: potash, soda, carbonate of lime, silica, magnesia, iron,
+phosphorus, and manganese in their various compounds are all present
+in the rocks of which mountains are composed. We must again fall back
+upon "Modern Painters" for an effective description of the forming of
+soil by destruction of the hills:--
+
+   "The higher mountains suffer their summits to be broken into
+   fragments and to be cast down in sheets of massy rock, full, as
+   we shall presently see, of every substance necessary for the
+   nourishment of plants; these fallen fragments are again broken
+   by frost, and ground by torrents into various conditions of
+   sand and clay,--materials which are distributed perpetually by
+   the streams farther and farther from the mountain's base. Every
+   shower that swells the rivulets enables their waters to carry
+   certain portions of earth into new positions, and exposes new
+   banks of ground to be moved in their turn.... The process is
+   continued more gently, but not less effectively, over all the
+   surface of the lower undulating country; and each filtering
+   thread of summer rain which trickles through the short turf of
+   the uplands is bearing its own appointed burden of earth down
+   on some new natural garden in the dingles beneath."
+
+It may be laid down as a simple economic truth, that no nation can be
+powerful, rich, or prosperous, unless it possess in the first place
+a good soil. Other conditions, such as large navigable rivers, a
+good seaboard for harbouring ships, are also important; but unless
+the land will yield plenty of food, the population cannot be very
+great, for people must be fed. Foreign supplies of corn at a low
+price, meat and provisions of various kinds, supplement what is
+grown in England; but without a good soil we could not have become a
+powerful nation.
+
+A high state of civilisation is in a large measure to be traced to
+climate and soil. The sequence is somewhat as follows:--
+
+Mountains collect rain.
+
+Rain fills the rivers.
+
+Rivers make rich alluvial plains.
+
+Agriculture follows; and food is produced.
+
+Abundant food maintains a large population.
+
+The population works to supply its various wants; such as roads,
+railways, ships, houses, machinery, etc. Then follows exchange with
+other countries. They send us what they can best produce, and we send
+them what we can best and most easily produce, and so both parties
+gain.
+
+Thus towns spring up. Education, refinement, learning, and the higher
+arts follow from the active life of towns, where more brain-work is
+required, and the standard of life is higher.
+
+And thus we may, in imagination, follow step by step the various
+stages by which the highest phases of civilisation are brought to
+pass, beginning at the mountains and ending with human beings of
+the highest type,--the philosopher, artist, poet, or statesman, not
+omitting the gentler sex, who are often said to rule the world.
+
+The following lines of Milton possess, in the light of these facts, a
+deeper meaning than the poet probably intended to convey:--
+
+    "Straight mine eye hath caught new pleasures
+    Whilst the landscape round it measures:
+    Russet lawns and fallows grey,
+    Where the nibbling flocks do stray;
+    Mountains on whose barren breast
+    The labouring clouds do often rest;
+    Meadows trim with daisies pied,
+    Shallow brooks and rivers wide;
+    Flowers and battlements it sees
+    Bosomed high in tufted trees,--
+    Where perhaps some beauty lies,
+    The cynosure of neighbouring eyes."
+
+With a little rearrangement of the lines, the sequence we have
+indicated above would be well illustrated. The mountains must come
+first; then the clouds, ready to bring forth their rain; then the
+brooks and rivers, then "russet lawns and fallows grey,"--with their
+"nibbling flocks." Then come the human elements in the scene,--the
+"towers and battlements," containing armed warriors, well fed, no
+doubt, and ready to do their master's bidding; lastly, the lady
+who adorns the home of her lord, and, let us hope, makes it worth
+fighting for.
+
+For commercial purposes, large navigable rivers are of great use. And
+in spite of the modern railway, rivers still exert an influence in
+determining the routes followed by trade. London, Liverpool, Glasgow,
+and other busy centres of life owe their importance to the rivers
+which flow through them, especially since they are tidal rivers.
+Heavily laden barges may be seen from London Bridge going up and down
+with the tide every day.
+
+Since the direction as well as the existence of large rivers is
+regulated by mountains, it is clear that mountains have a very direct
+influence on the trade of the world.
+
+
+_Mountains supply many of our wants._ Besides water and soil, how
+many useful things come from the hills! Their slopes, watered by
+the clouds, frequently support an abundant growth of pine forest;
+and thus we get wood for the shipwright and joiner. Again, mountains
+are composed of harder rocks than we find in the plains, and that
+is one reason why they stand out high above the rest of the world.
+Their substance has been hardened to withstand for a longer time the
+destruction to which all rocks are subjected. They have been greatly
+compressed and generally more or less hardened by subterranean heat.
+We bake clay and make it into hard bricks; so Nature has baked and
+otherwise hardened the once soft strata of which mountains are
+chiefly composed, converting them into slates, schist, gneiss, and
+other kinds of rock called "metamorphic" by geologists, because they
+have been altered or metamorphosed from their original condition (see
+chapter viii., page 277). Again, granite, basalt, and other rocks
+known as "igneous," which once existed in a molten condition, have
+forced their way up from subterranean regions into the rocks forming
+mountain-chains; and a good deal of the hardening just alluded to is
+due to the presence of these fiery intruders, which have baked and
+hardened the rocks around them to a considerable extent, altering
+at the same time their mineral composition. The same causes which
+led to the injection of granite, basalt, and other igneous rocks in
+mountain-ranges brought other consequences in their train. Whatever
+the causes, they were closely connected with volcanic eruptions, so
+that highly heated water and steam found their way through cracks and
+other fissures in the rocks; and in the course of time the chemical
+actions thus set up led to the deposition of valuable metallic ores
+within these fissures. In this way mineral veins were formed; and
+volcanic action seems to be largely responsible for the production of
+minerals. Thus we find around Vesuvius, and in fact in all volcanic
+regions, large and varied supplies of minerals. Now, the geologist
+discovers that many mountain-chains--such, for example, as the
+Grampians, Alps, and Carpathians--have in past geological periods
+been the seats of volcanic action on a grand scale; and so we need
+not be surprised to learn that mountainous countries yield large
+supplies of valuable gems and metallic ores (see chapter viii.,
+page 277). Even in the days of Solomon, the active and business-like
+Phoenicians were carrying on trade with Great Britain; and the tin
+came from Cornwall. Besides tin, gold, silver, lead, copper, zinc,
+and other metals come from our hills. Now, however, we get our copper
+mostly from the Andes, and our gold from Australia or South Africa,
+because it can be got more cheaply from these countries, to which
+many of our Cornish miners have emigrated.
+
+Precious stones also come chiefly from the hills, for the same
+reason; for they were formed at the same time and by the same causes.
+Cairngorms, agates, chalcedony, jasper, onyx, topaz, diamonds, and
+many other gems are silent but certain witnesses to the action of
+subterranean heat, acting long ago on the rocks which we now see
+standing up high above the general surface of the ground, though
+once they were buried deep down below the surface. Diamonds as well
+as gold are often got from the beds of streams, but this is easily
+accounted for; the streams have washed them out and brought them down
+from the hills.
+
+The following words from the Book of Job (xxviii. 5) might well be
+applied to the hills.
+
+    "As for the earth, out of it cometh bread:
+    And underneath it is turned up as it were by fire.
+    The stones thereof are the place of sapphires,
+    And it hath dust of gold."
+
+We have thus explained the three principal services rendered by
+mountains, but some others remain to be mentioned.
+
+
+_Mountains have an important influence on climate._ The climate of
+highlands everywhere has certain peculiarities which distinguish
+it from that of adjacent lowlands. The air resting on mountains is
+less dense than that of the lowlands, and hence has fewer molecules
+to obstruct the entering sunbeams by day, or to stop the outward
+radiation at night. Therefore mountain air must be cooler; and so we
+find that on mountains the mean, or average, annual temperature is
+lower. This rarity of the air causes the ground to become hotter by
+day and colder by night than the ground of the plains; and so the
+extremes of temperature are greater. These extremes are injurious to
+vegetation in the higher regions, and the want of moisture still
+more so. But mountain-slopes _up to a certain height_ usually have
+a moist climate; that is, they have more clouds and rain than the
+surrounding lowlands. Below the region of snow there is generally
+a heavy growth of forest; and forests in their turn exercise an
+important influence, helping to collect moisture, and in various ways
+to prevent extremes either of heat or cold.
+
+The earth is divided into three well-marked zones or belts of
+climate: (1) The torrid zone within the tropics, where the sun is
+vertical twice a year, and days and nights are nearly equal; (2)
+The temperate zones, where the sun's rays come more obliquely,
+and so are less powerful, and where the length of day and night
+varies considerably; and (3) The frigid zones, round each of the
+poles, regions of intense cold, where for six months of the year
+the sun is never seen. Now, these broad divisions, so familiar to
+school children, are considerably interfered with by the height of
+various districts above the sea-level, or, as geographers say, by
+altitude. High ranges of mountains bring somewhat arctic conditions
+with them, even in low latitudes, where one would expect great
+heat. Thus the climate of the plains is very different from that
+of their neighbouring mountain-ranges, although their latitudes are
+practically the same. Travellers in Switzerland know how hot it can
+be in the Rhone Valley or in the plain of Lombardy, and how much
+cooler it is when you get up among the glaciers and the snowfields.
+Or to take an illustration from Great Britain: a hot summer would be
+somewhat trying in Edinburgh, Glasgow, or even Inverness, because
+they lie low, while among the Grampians, on Speyside, or Braemar, it
+would be very pleasant.
+
+Vegetation follows climate. The sultry plains of the Ganges show
+a luxuriant tropical vegetation, while on the middle slopes of
+the Himalayas the climate is temperate, like that of Europe, and
+consequently the vegetation resembles that of a temperate region; and
+the highest parts of this great range are like polar latitudes in
+their climate, and partly also in their vegetation.
+
+The arctic character of the climate of high mountain regions shows
+itself in the flora; for on the High Alps and the Highlands of
+Scotland and Norway, we find no small number of truly arctic plants
+whose home is much farther north. A very long time ago, when the
+climate of the whole of Northern Europe was extremely severe, and
+when great glaciers descended from the mountains into the plains,
+so that the aspect of the country was somewhat similar to that of
+Greenland at the present day, arctic plants and animals came down
+from their northern home, and flourished abundantly. This was during
+the _Great Ice Age_, which has left behind unmistakable evidences
+which the geologist can interpret as if they were written records.
+Then for some reason the climate became milder, the glaciers melted
+away, in Great Britain at least; but these arctic plants were left
+behind, and flourished still on the cool mountains, though they died
+out on the warm plains (see chap. iv., pp. 123-124).
+
+  [Illustration: SNOW ON THE HIGH ALPS. FROM A PHOTOGRAPH BY MR.
+  DONKIN.]
+
+_Mountains help to cause movement and change in the atmosphere._
+Let us see how this takes place. Mountains expose on one side their
+masses of rock to the full heat of the sun. Rocks are capable of
+becoming highly heated under a blazing sun: we have known stone
+walls, even in England, to be almost too hot to touch; and perhaps
+the reader may have often noticed the quivering of the hot air as
+it rises from the ground on a summer day, especially over a road or
+any piece of bare rocky ground. This quivering tells us that the air
+is highly heated by the ground beneath, and is consequently rising.
+You know how the pebbles look beneath a clear running stream; and
+the things which we see through air in this state all seem to be
+similarly moving or quivering. It is easy then to imagine how masses
+of heated air would rise up from the side of a mountain-range which
+faces the sun,--that is, the southern side,--while on the other, or
+northern side they cast a soft shadow for leagues over the plains
+at their feet. In this way mountains divide a district into two
+different climates, with a light warm air on their southern slopes,
+and colder air on the northern, and the rising of the warm air will
+cause a certain amount of circulation and movement. Hence mountains
+help to make currents in the atmosphere, and these currents produce
+important consequences.
+
+When mountain-ranges trend more or less directly across the direction
+of prevailing winds, they always have a moist side and a dry one. In
+the torrid zone, where easterly winds prevail, the eastern slope is
+usually the moist side; but in higher latitudes, as, for example, in
+Europe, the western side of mountain-ranges receives the greatest
+amount of rainfall, because westerly winds prevail there.
+
+
+_Mountains are barriers dividing not only one nation from another,
+but separating also various tribes of plants and animals._ It will
+be readily understood that with the exception of birds, whose powers
+of flight render them independent of physical barriers, most animals
+find mountains more impassable than men do. We can make roads and
+railways, but they cannot thus aid their powers of locomotion; hence
+mountains put limits to their migrations. Still, climate and food
+supplies have a greater influence in determining the boundaries of
+zoölogical provinces (see chapter iv.).
+
+
+_Mountains are the backbones of continents._ A glance at a map of
+the world will show that there is evidently a close connection
+between continents and great mountain-chains. This connection shows
+itself both in the shapes and general direction of continents.
+Thus, the long continuous line of mountain-chain which extends from
+the southern spur of the Andes to the northern end of the Rocky
+Mountains,--a distance of about nine thousand miles,--corresponds
+with the general trend of the North American continent, and forms
+the axis or backbone of that vast tract of land. It seems as if the
+sea on its western side were kept at bay by this great rocky wall,
+while on its eastern side the rivers have formed new land. A line of
+mountains is often the coast line, for the sea cannot overcome it
+unless subsidence takes place. The backbone of Asia and Europe runs
+east and west, and the continental area of the Old World follows the
+same general direction.
+
+These are the chief uses of mountains, and the facts which we have
+brought forward will serve to show how indispensable they are. The
+following eloquent passage from "Modern Painters" may form a fitting
+close to the present chapter:--
+
+   "And thus those desolate and threatening ranges which in nearly
+   all ages of the world men have looked upon with aversion or
+   with horror, and shrunk back from as if they were haunted by
+   perpetual images of death, are in reality sources of life
+   and happiness, far fuller and more beneficent than all the
+   bright fruitfulness of the plain. The valleys only feed; the
+   mountains feed and guard and strengthen us. We take our ideas
+   of fearfulness and sublimity alternately from the mountains and
+   the sea; but we associate them unjustly. The sea-wave, with
+   all its beneficence, is yet devouring and terrible; but the
+   silent wave of the blue mountain is lifted towards heaven in a
+   stillness of perpetual mercy; and the one surge, unfathomable
+   in its darkness, the other unshaken in its faithfulness, for
+   ever bear the seal of their appointed symbolism:--
+
+    "'Thy _righteousness_ is like the great mountains,
+    Thy _judgements_ are a great deep.'"
+
+
+
+
+CHAPTER III.
+
+SUNSHINE AND STORM ON THE MOUNTAINS.
+
+    I would entreat your company
+    To see the wonders of the world.
+
+    _Two Gentlemen of Verona._
+
+
+"The spirit of the hills is action, that of the lowlands repose."[9]
+The plains, with their peaceful meadows and meandering streams, might
+almost be said to be asleep; but the mountains are wide awake. They
+are emphatically scenes of violent or rapid action. The wind blows
+more fiercely among the mountain-peaks than over the plains below;
+heat and cold are more extreme; and every process of change or decay
+seems quickened.
+
+  [9] Ruskin, "Modern Painters."
+
+Avalanches, falls of rock, earthquakes, storms, and floods exhibit
+the more terrible aspects of the hills. Yet they have their gentler
+moods: witness the brightness of the starry sky overhead, and its
+intense blue by day, the wonderful sunrises and sunsets, the lovely
+effects of light and shade, of cloud and mist, the stillness and
+silence of the eternal snows in summer, and the beauty of the Alpine
+flower.
+
+Let us see what those who know mountains best have to say about the
+wonderful things they have seen there. To begin with sunset and
+sunrise. Professor Bonney remarks,--
+
+   "Not the least interesting peculiarity of an Alpine sunset
+   is the frequency with which its most beautiful effects are
+   revealed quite unexpectedly. Often at the close of a rainy
+   afternoon, the clouds, just before the sun goes down, break,
+   roll up, sometimes disperse as if by magic, in the glory of
+   those crimson rays that come darting upon them and piercing
+   every rift. Many a time have I watched the vapours around a
+   mountain-peak curling lightly upwards, and melting away into
+   the sky, till at last the unclouded summit glowed with flushes
+   of orange and rose, ere it grew pale and dead in its shroud of
+   fresh-fallen snow."[10]
+
+  [10] The Alpine Regions of Switzerland.
+
+Here is a description by Professor Tyndall of a sunset witnessed in
+the neighbourhood of the Weisshorn:--
+
+   "As the day approached its end, the scene assumed the most
+   sublime aspect. All the lower portions of the mountains were
+   deeply shaded, while the loftiest peaks, ranged upon a
+   semicircle, were fully exposed to the sinking sun. They seemed
+   pyramids of solid fire; while here and there long stretches
+   of crimson light drawn over the higher snowfields linked the
+   glorified summits together. An intensely illuminated geranium
+   flower seems to swim in its own colour, which apparently
+   surrounds the petals like a layer, and defeats by its lustre
+   any attempt of the eye to seize upon the sharp outline of the
+   leaves. A similar effect has been observed upon the mountains;
+   the glory did not seem to come from them alone, but seemed also
+   effluent from the air around them. This gave them a certain
+   buoyancy which suggested entire detachment from the earth.
+   They swam in splendour which intoxicated the soul; and I will
+   not now repeat in my moments of soberness the extravagant
+   analogies which ran through my brain. As the evening advanced,
+   the eastern heavens low down assumed a deep purple hue, above
+   which, and blended with it by infinitesimal gradations, was a
+   belt of red, and over this again zones of orange and violet. I
+   walked round the corner of the mountain at sunset, and found
+   the western sky glowing with a more transparent crimson than
+   that which overspread the east. The crown of the Weisshorn was
+   embedded in this magnificent light. After sunset the purple
+   of the east changed to a deep neutral tint; and against the
+   faded red which spread above it, the sun-forsaken mountains
+   laid their cold and ghostly heads. The ruddy colour vanished
+   more and more; the stars strengthened in lustre, until finally
+   the moon and they held undisputed possession of the blue-grey
+   sky."[11]
+
+  [11] Mountaineering in 1861 (Longman).
+
+
+Marvellous sunsets are to be witnessed from the mountains of the New
+World. The following is a short and graphic description of sunset
+glories on the Sierra Nevada Mountains by Mr. Clarence King, whose
+name is well known to geologists:--
+
+   "While I looked, the sun descended, shadows climbed the
+   Sierras, casting a gloom over foothill and pine, until at last
+   only the snow summits, reflecting the evening light, glowed
+   like red lamps along the mountain-wall for hundreds of miles.
+   The rest of the Sierra became invisible. The snow burned for a
+   moment in the violet sky, and at last went out."
+
+These marvellous effects appeal powerfully to our sense of beauty
+and produce in most minds feelings of intense delight; but they also
+appeal to the reasoning faculty in man, and an intelligent observer
+naturally inquires, "Why are these things so? How are those glorious
+colours of crimson, orange, and yellow produced?" A full explanation
+cannot be attempted here; but this much may perhaps be said without
+tiring the patience of the reader. White light, such as sunlight or
+the light from an electric arc, is composed of all the colours of the
+rainbow,--violet, indigo, blue, green, yellow, orange, and red. A ray
+of sunlight on passing through a prism is split up into all these
+colours in the above order, and we get them arranged in a band which
+is known as the spectrum. Thus it is proved that white light is made
+up of all colours (black is not a colour, but the absence of colour).
+Now, when the sun is low down in the sky, as at sunset, only some of
+these colour-rays are able to pass through the atmosphere and so to
+reach our eyes, while others are stopped in passing through very many
+miles of atmosphere (as they must obviously do when the sun is low).
+Those which are stopped are the blue rays and others allied to blue,
+such as purple and green; but the red and yellow rays are able to
+pass on till they come to us. Hence red, yellow, and orange are the
+prevailing sunset tints.
+
+What, then, becomes of the missing blue rays? They are caught by the
+myriads of little floating particles in the air, and reflected away
+from us. That is why we do not see them; their course is turned
+back, just as waves breaking against a stone sea-wall are turned
+back or reflected. A person situated _behind_ such a wall will not
+see the waves which break against it; but suppose a _very_ big wave
+came: it would come right over, and then we should soon become aware
+of its presence. So it is with the little waves of light: some are
+stopped and turned back as they break against the myriads of little
+dust particles and the still more numerous particles of mist always
+floating in the air; while others, which are larger, break over
+them and travel on undisturbed until they reach our eyes. Now, the
+larger waves of light are the red waves, while the smaller ones are
+the blue waves; hence there is no difficulty in understanding why
+the red waves (or vibrations) are seen at sunset and sunrise, to
+the exclusion of the blue waves. But it must be borne in mind that
+light-waves are of infinitesimal smallness, thousands and thousands
+of them going to make up an inch. Sound also travels in waves, and
+the phenomena of sound serve to illustrate those of light; but
+sound-waves are very much larger.
+
+The reason why the sky overhead appears blue is that we see the blue
+rays reflected down to the earth from myriads of tiny dust and water
+particles, while the red rays pass on over our heads, which is just
+the reverse of what happens at sunset.
+
+On the southern slopes of the Alps the blues of the sky are generally
+very different from those on the northern side; and this is probably
+due to the greater quantity of water-vapour in the air, for the moist
+winds come from the south. Sunrises in the Alps are quite as glorious
+to behold as sunsets; but comparatively few people rise early enough
+to see them. Speaking generally, it may be said that in Alpine
+sunrises the prevailing colours are orange and gold, in sunsets
+crimson or violet-pink. After a cool night the atmospheric conditions
+will obviously be different from those which exist after a warm day,
+and more water-vapour will have been condensed into mist or cloud.
+Hence we should expect a somewhat different effect.
+
+The snowfields on high ranges of mountains are of a dazzling
+whiteness; and their bright glare is so great as to distress the
+eyes of those who walk over them without blue glasses, and even
+to cause inflammation. At these heights the traveller is not only
+exposed to the direct rays of the sun, untempered save for a thin
+veil of rarefied air, but also to an intense glare produced by the
+little snow-crystals which scatter around the beams of light falling
+upon them. Scientific men, who have studied these matters, say that
+the scorching of the skin and "sun-burning" experienced by Alpine
+travellers is not caused, as might be supposed, by the heat of the
+sun, but by the rays of light darting and flashing on all sides from
+myriads of tiny snow-crystals.
+
+Occasionally a soft lambent glow has been observed on snowfields
+at night. This is a very curious phenomenon, to which the name of
+"phosphorescence" has, rightly or wrongly, been given. A pale light
+may often be seen on the sea during a summer night, when the water
+is disturbed in any way; and if one is rowing in a boat, the oars
+seem glowing with a faint and beautiful light. It is well known that
+this is caused by myriads of little light-producing animalcules
+in the sea-water. But we can hardly suppose that the glow above
+referred to is produced by a similar cause. One observer says the
+glow is "something like that produced by the flame of naphtha;"
+and he goes on to say that at every step "an illuminated circle
+or nimbus about two inches in breadth surrounded our feet, and we
+seemed to be ploughing our way through fields of light, and raising
+clods of it, if I may be allowed the expression, in our progress."
+Another observer, also an Alpine traveller, says that at almost every
+footstep the snowy particles, which his companion in front lifted
+with his feet from the freshly fallen snow, fell in little luminous
+showers. The exact cause which produces this strange effect at night
+has not been ascertained.
+
+There is another curious phenomenon often seen just before sunset on
+a mountain in Hungary. It is known as "The Spectre of the Brocken."
+The Brocken is the highest summit of the Hartz Mountains. As you step
+out upon the plateau upon the top of the hill, your shadow, grim and
+gigantic, is apparently flung right out against the eastern sky,
+where it flits from place to place, following your every movement.
+The explanation is simply this: to the east of the Hartz Mountains
+there is always a very dense and hazy atmosphere, so dense that it
+presents a surface capable of receiving the impression of a shadow,
+and of retaining it, as a wall does. The shadows are really close
+at hand, not a long way off, as might at first sight be supposed. If
+very far away, they would be too faint to be visible.
+
+
+In all mountainous regions the permanent habitations of men cease
+at a limit far below the most elevated points reached by the
+mountain-climber. St. Veran and Gargl, the highest villages of France
+and Germany, are situated at the respective heights of 6,591 and
+6,197 feet; but the Hospice of St. Bernard, in Switzerland, built
+centuries ago to shelter travellers when benumbed with the cold, is
+much more elevated, its height being 8,110 feet above sea-level. The
+most elevated cluster of houses in the world is the convent of Hanle,
+inhabited by twenty Thibetan priests; its height is 14,976 feet. None
+of the villages of the Andes, except perhaps that of Santa Anna, in
+Bolivia, have been built at so great a height.
+
+Travellers who venture to ascend lofty mountains not only have to
+suffer all the rigours of cold and run the risk of being frozen
+on their route, but they may also experience painful sensations
+owing to the rarefaction of the air. It would naturally be supposed
+that at an elevation at which the pressure of the atmosphere is
+reduced to one half, or even to one fourth that of the plains below,
+a certain uneasiness should be caused by the change, the more so
+since other conditions, such as warmth and moisture, are different.
+Undaunted climbers, like Professor Tyndall, who have never felt the
+effect of this "mountain-sickness" (_mal de montagne_), deny that
+the sensations proceed from anything else than mere fatigue. In the
+Himalayas, the traveller does not begin to suffer from the attacks of
+this ailment until he has reached a height of 16,500 feet; while on
+the Andes a large number of persons are affected by it at an altitude
+of 10,700 feet. In the South American mountains, the symptoms are
+much more serious: to the fatigue, head-ache, and want of breath are
+added giddiness, sometimes fainting-fits, and bleeding from lips,
+gums, and eyelids. The aeronaut, however, who is spared all the
+fatigue of climbing, rarely suffers any inconvenience except from
+cold, at such elevations. But on rising to greater heights, 30,000 or
+40,000 feet, the malady shows itself; and if the balloon continued to
+rise, the aerial voyager would infallibly perish.
+
+Professor Bonney says:--
+
+   "I have occasionally seen persons singularly affected on high
+   mountains; and as the barometer stands at about sixteen inches
+   on Mont Blanc, and at thirty at sea-level, one would expect
+   this great difference to be felt. Still, I do not think it easy
+   to separate the inconveniences due to atmosphere from those
+   caused by unwonted fatigue, and am inclined to attribute most
+   of them to the latter."
+
+But the fact that the aeronaut suffers seems conclusive.
+
+
+The violent storms which break upon mountain districts often cause
+floods of considerable magnitude, such as may be compared with the
+memorable bursting of the Holmfirth reservoir. Hardly a year passes
+without considerable damage being done: bridges are swept away; roads
+are buried under torrents of mud, and fields overwhelmed with débris.
+In August of the year 1860 a severe storm was witnessed by visitors
+staying at Zermatt. It began with a thunder-storm; and rain fell for
+about thirty-six hours, after which, as may be supposed, the torrents
+were swollen far beyond their usual size. Lower down in the valleys
+much harm was done, but there one bridge only was swept away. It
+was, however, an awful sight to see the Visp roaring under one of the
+bridges that remained, and to hear the heavy thuds of the boulders
+that were being hurried on and dashed against one another by the
+torrent.
+
+In September, 1556, the town of Locarno, in the Canton Ticino, was
+visited by a destructive storm and flood. The day began by several
+shocks of earthquake, followed, about five o'clock, by a terrific
+gale from the south. Part of the old castle was blown down; the doors
+of St. Victor's Church were burst open by a blast while the priest
+was at the altar; and everything within was overturned. At midday the
+clouds were so thick that it was almost as dark as night. A violent
+thunder-storm and torrents of rain followed, lasting from two to six
+o'clock in the evening. The rivulets all became torrents; the stream
+flowing through the town was so choked by uprooted trees and rocks
+that its water flooded the streets and almost buried them under mud
+and gravel. Such a sight as this gives one a powerful impression of
+the geological work of streams when greatly swollen; for all this
+débris must have been brought down from the surrounding mountains.
+Many lives were lost by this calamity, and a great deal of property
+was destroyed. Late in the year, during unsettled weather, the
+traveller often encounters on Alpine passes a sudden storm of snow,
+accompanied by violent gusts of wind, which fill the air with drifted
+flakes; so that becoming bewildered, he loses his way, and at last
+sinks down benumbed with cold and dies. Many a frequented pass in
+Switzerland has been the scene of death from this cause. Exhausted
+with fatigue, and overcome with cold, the traveller sinks down by the
+wayside, and the guides, after having in vain endeavoured to urge him
+on, are compelled, in order to save their own lives, to leave him to
+his fate and press forward. The name "Tourmente" is given to these
+storms.
+
+On the tops of the highest mountains, even in very fine weather,
+the wind often blows with great force; and the north wind, supposed
+to be the mountaineer's best friend, is sometimes his enemy. It
+not unfrequently happens that a gale renders the passage of some
+exposed slope or ridge too dangerous, or the intense cold produces
+frost-bites, so that an expedition has to be abandoned when success
+is within reach, which naturally is very annoying. Professor Bonney,
+speaking of such a gale which he experienced in 1864, says,--
+
+   "The cold was something horrible; the wind seemed to blow not
+   round, but through me, freezing my very marrow, and making my
+   teeth chatter like castanets; and if I stopped for a moment, I
+   shook as if in an ague-fit. It whisked up the small spiculæ of
+   frozen snow, and dashed them against my face with such violence
+   that it was hardly possible to look to windward. Thin sheets of
+   ice as large as my hand were whirled along the surface of the
+   glacier like paper.... When these gales are raging, the drifted
+   snow is blown far to leeward of the peaks in long streamers
+   like delicate cirrus-clouds; and on such occasions the mountain
+   is said by the guides _fumer sa pipe_ (to smoke his pipe). This
+   Mont Blanc was doing to some purpose the day that we were upon
+   him."
+
+It is a curious fact that these gales are often confined to the
+crests of the mountains, so that the wind may be raging among the
+peaks while a few hundred feet lower down there is comparative calm.
+
+The chief of the prevailing winds in the Alps is the Föhn. This is
+a hot blast from the south which probably comes from the African
+deserts. On its approach the air becomes close and stifling, the sky,
+at first of unusual clearness, gradually thickens to a muddy and
+murky hue, animals become restless and disquieted by the unnatural
+dryness of the hot blast which now comes sweeping over the hills. In
+some villages, it is said, all the fires are extinguished when this
+wind begins to blow, for fear lest some chance spark should fall on
+the dry wooden roofs and set the whole place in a blaze. Still the
+Föhn is not altogether an "ill wind that blows nobody any good,"
+for under its warm touch the winter snows melt away with marvellous
+rapidity. In the valley of Grindelwald it causes a snow-bed two
+feet thick to disappear in about a couple of hours, and produces in
+twenty-four hours a greater effect than the sun does in fifteen days.
+There is a Swiss proverb which rather profanely says: "If the Föhn
+does not blow, the golden sun and the good God can do nothing with
+the snow."
+
+In summer-time, however, the south wind is never welcome, for the
+vapour which it brings from the Italian plains is condensed by the
+snows of the Alps, and streams down in torrents of rain.
+
+
+A thunder-storm is always a grand spectacle. Among mountains such
+storms are more frequent than on the plains, and also, as might be
+expected, far more magnificent, especially at night. Flashes, or
+rather sheets, of unutterable brilliancy light up the sky; distant
+chains of mountains are revealed for a moment, only to be instantly
+eclipsed by the pall of night. Says Professor Bonney,--
+
+   "No words can adequately express the awful grandeur of these
+   tempests when they burst among the mountains. I have often
+   been out in them,--in fact, far more frequently than was
+   pleasant; but perhaps the grandest of all was one that welcomed
+   me for the first time to Chamouni. As we entered the valley,
+   and caught sight of the white pinnacles of the _glacier des
+   Bossons_, a dark cloud came rolling up rapidly from the west.
+   Beneath it, just where two tall peaks towered up, the sky
+   glowed like a sheet of red-hot copper, and a lurid mist spread
+   over the neighbouring hills, wrapping them, as it seemed, in a
+   robe of flame. Onward rolled the cloud; the lightning began to
+   play; down the valley rushed a squall of wind, driving the dust
+   high in air before it, and followed by a torrent of rain.
+   Flash succeeded flash almost incessantly,--now darting from
+   cloud to cloud; now dividing itself into a number of separate
+   streaks of fire, and dancing all over the sky; now streaming
+   down upon the crags, and at times even leaping up from some
+   lofty peak into the air. The colours were often most beautiful,
+   and bright beyond description."
+
+  [Illustration: A STORM ON THE LAKE OF THUN. AFTER TURNER.]
+
+The mountain traveller, when caught in a thunder-storm, undergoes a
+strange experience, not unattended with danger. One observer[12] thus
+describes his sensations:--
+
+  [12] Mr. R. S. Watson, in "The Alpine Journal," vol. i., p. 143.
+
+   "A loud peal of thunder was heard; and shortly after I observed
+   that a strange singing sound, like that of a kettle, was
+   issuing from my alpenstock. We halted, and finding that all the
+   axes and stocks emitted the same sound, stuck them into the
+   snow. The guide from the hotel now pulled off his cap, shouting
+   that his head burned; and his hair was seen to have a similar
+   appearance to that which it would have presented had he been
+   on an insulated stool under a powerful electrical machine. We
+   all of us experienced the sensation of pricking and burning in
+   some part of the body, more especially in the head and face,
+   my hair also standing on end in an uncomfortable but very
+   amusing manner. The snow gave out a hissing sound, as though a
+   heavy shower of hail were falling; the veil on the wide-awake
+   of one of the party stood upright in the air; and on waving
+   our hands, the singing sound issued loudly from the fingers.
+   Whenever a peal of thunder was heard, the phenomenon ceased, to
+   be resumed before its echoes died away. At these times we felt
+   shocks, more or less violent, in those portions of the body
+   which were most affected. By one of these shocks my right arm
+   was paralysed so completely that I could neither use nor raise
+   it for several minutes, nor indeed until it had been severely
+   rubbed; and I suffered much pain in it at the shoulder-joint
+   for some hours."
+
+The successive layers of snow which fall on the mountains do not
+remain there for ever. Unless got rid of in some way their thickness
+would mount up to an enormous extent. It is reckoned that on the
+Alps the average yearly fall of snow is thirty-three feet. In the
+course of a century, therefore, the height of these mountains would
+be increased by 3,300 feet, which we know is not the case. Various
+causes prevent its accumulating, among which we may mention the
+powerful influence of the sun's rays, the evaporation promoted by
+the atmosphere, the thawing influence of rain and mist, avalanches,
+and lastly, which is perhaps the most important, the fact that the
+snow composing the snowfields, as they are called, of the high
+regions slowly creeps down towards the valleys, where they move
+along as glaciers, the ends of which are gradually melted away by
+the warm air surrounding them, and thus the muddy glacier-streams
+are originated. Few perils are more dreaded by the inhabitant of
+the Alps than those of the avalanches. The particular way in which
+each avalanche descends is varied according to the shape of the
+mountain, the condition of the snow, and the time of the year. Hence
+there are three different kinds of avalanche. First, there is the
+ice-avalanche. The smaller glaciers, which, in the Alps, cling to the
+upper slopes of the higher mountains, frequently terminate abruptly
+on the edge of some precipice. Thus the ice, urged on by the pressure
+of the masses above it, moves forward until it plunges over and
+falls into the abyss below. Large portions break off; and these, as
+they bound down the cliffs, are dashed into countless pieces, which
+leap from crag to crag high into the air: now the falling mass, like
+some swollen torrent, dashes with sullen roar through a gully, now,
+emerging, crashes over a precipice, or spreads itself out like a fan,
+as it hisses down a snow-slope. These avalanches expend their force
+in the higher regions, and are harmless, unless any one happens to
+be crossing their track at the time; but accidents from this source
+can generally be avoided. In the distance the avalanches look like
+waterfalls of the purest foam, but when approached are found to be
+composed of fragments of ice of every size, from one, two, or more
+cubic yards down to tiny little balls. In spring and summer, when the
+white layers, softened by the heat, are falling away every hour from
+the lofty summits of the Alps, the pedestrian, taking up a position
+on some adjacent headland, may watch these sudden cataracts dashing
+down into the gorges from the heights of the shining peaks. Year
+after year travellers seated at their ease on the grassy banks of
+the Wengern Alp have watched with pleasure the avalanches rolling to
+the base of the silvery pyramid of the Jungfrau. First, the mass of
+ice is seen to plunge forth like a cataract, and lose itself in the
+lower parts of the mountain; whirlwinds of powdered snow, like clouds
+of bright smoke, rise far and wide into the air; and then, when the
+cloud has passed away, and the region has again assumed its solemn
+calm, the thunder of the avalanche is suddenly heard reverberating
+in deep echoes in the mountain gorges, as if it were the voice of the
+mountain itself.
+
+The other two kinds of avalanche are composed of snow. The
+dust-avalanche usually falls in winter-time, when the mountains are
+covered deep with fresh-fallen snow. Such masses of snow, not yet
+compacted into ice, rest insecurely upon the icy slopes, and hang
+in festoons and curtains over the peaks, or lie on smooth banks of
+pasture, until some accident, such as a gust of wind, breaks the
+spell, and the whole mass slides down into the valley below. These
+avalanches are accompanied by fearful blasts of wind which work dire
+destruction. Almost the whole village of Leukerbad was destroyed by
+one of these on the 14th of January, 1719, and fifty-five persons
+perished. In 1749, more than one hundred persons were killed in the
+village of Ruaras (Grisons), which during the night was overwhelmed
+by an avalanche. So silently were some of the houses buried that the
+inhabitants, on waking in the morning, could not conceive why the
+day did not dawn. It is said, though it seems almost incredible,
+that in the time of the Suabian War, in the year 1498, one of these
+avalanches swept four hundred soldiers over a cliff, and they all
+escaped without serious injury.
+
+The army of General Macdonald, in his celebrated passage of
+the Splügen in December, 1800, suffered severely from these
+dust-avalanches. A troupe of horse was completely cut through while
+on the march; and thirty dragoons were precipitated into a gulf below
+the road, where they all perished. And again, some days afterwards,
+in descending a gorge, the columns were repeatedly severed by
+avalanches; and more than one hundred soldiers, with a number of
+horses and mules, were lost. On one of these occasions the drummer
+of a regiment was carried away; and it is said that they heard him
+beating his drum in the gorge below, in the hope that his comrades
+would come to his rescue. Help, however, was out of the question. The
+sounds gradually became fainter, and the poor lad must have perished
+in the cold.
+
+The ground-avalanches are different from those just described,
+consisting of dense and almost solid masses of snow which have lain
+for a long time exposed to atmospheric influences. They are much
+heavier than the dust-avalanches, and therefore more destructive;
+so that the inhabitants take great pains to protect themselves from
+this source of danger. Thickly planted trees are the best protection
+against avalanches of every kind. Snow which has fallen in a wood
+cannot very well shift its place; and when masses of snow descend
+from the slopes above, they are unable to break through so strong
+a barrier. Small shrubs, such as rhododendrons, or even heaths and
+meadow-grass, are often sufficient to prevent the slipping of the
+snow; and therefore it is very imprudent not to allow them to grow
+freely on mountain-slopes. But it is still more dangerous to cut down
+protecting forests, or even to do so partly. This was illustrated by
+the case of a mountain in the Pyrenees, in the lofty valley of Neste;
+after it had been partially cleared of trees, a tremendous avalanche
+fell down in 1846, and in its fall swept away more than fifteen
+thousand fir-trees.
+
+The Swiss records tell us what a terrible scourge the avalanche can
+be in villages which in summer-time appear such calm and happy
+scenes of pastoral life. M. Joanne, in the introduction to his
+valuable "Itinéraire de la Suisse"[13] gives a list of twelve of
+the most destructive avalanches that have fallen in Switzerland. In
+old days they seem to have been as great a source of danger as in
+modern times. Thus we find that in the year 1500, a caravan of six
+hundred persons was swept away in crossing the Great St. Bernard;
+three hundred were buried under an avalanche which fell from Monte
+Cassedra (Ticino). Another one in the year 1720, at Obergestelen,
+in the Rhone Valley, destroyed one hundred and twenty cottages,
+four hundred head of cattle, and eighty-eight persons. The bodies
+were buried in a large pit in the village cemetery, on the wall
+of which was engraved the following pathetic inscription: "O God,
+what sorrow!--eighty-eight in a single grave!" ("Gott, welche
+Trauer!--acht und achtzig in einem Grab!")
+
+  [13] Conservateur Suisse, xlvi. p. 478, vol. xii.
+
+It is a curious fact that animals have a wonderful power of
+anticipating coming catastrophes. When human beings are unaware of
+danger, they are often warned by the behaviour of animals. Country
+people sometimes say that they can tell from the birds when the
+weather is about to change; and there is little doubt but that
+sea-gulls come inland before rough, stormy weather. But in the case
+of earthquakes the behaviour of birds, beasts, and even fishes is
+very striking. It is said that before an earthquake rats, mice,
+moles, lizards, and serpents frequently come out of their holes, and
+hasten hither and thither as if smitten with terror. At Naples, it
+is said that the ants quitted their underground passages some hours
+before the earthquake of July 26, 1805; that grasshoppers crossed
+the town in order to reach the coast; and that the fish approached
+the shore in shoals. Avalanches, it is well known, produce tremors
+similar to those due to slight earthquake shocks; and there are many
+stories in Switzerland of the behaviour of animals just before the
+catastrophe takes place. Berlepsch relates that a pack-horse on the
+Scaletta Pass, which was always most steady, became restive when
+an avalanche was coming; so that he was valuable to his owners in
+bad weather. One day, when near the summit of the pass, he suddenly
+stopped. They foolishly took no notice of his warning this time; but
+he presently darted off at full speed. In a few seconds the avalanche
+came and buried the whole party.
+
+If these stories can be relied upon, it would seem that animals are
+either more sensitive to very slight tremors of the earth, or else
+that they are more on the lookout than human beings. Perhaps North
+American Indians have learned from animals in this respect, for they
+can tell of a coming enemy on the march by putting their ears to the
+ground and listening.
+
+But there are worse dangers in the mountains than falls of snow and
+ice, for sometimes masses of rock come hurtling down, or worse still,
+the whole side of a mountain gives way and spreads ruin far and wide.
+Perpendicular or overhanging rocks, which seem securely fastened,
+suddenly become detached and rush headlong down the mountain-side.
+In their rapid fall, they raise a cloud of dust like the ashes
+vomited forth by a volcano; a horrible darkness is spread over a once
+pleasant valley; and the unfortunate inhabitants, unable to see what
+is taking place, are only aware of the trembling of the ground, and
+the crashing din of the rocks as they strike together and shatter one
+another in pieces. When the cloud of dust is cleared away, nothing
+but heaps of stones and rubbish are to be seen where pastures once
+grew, or the peasant ploughed his acres in peace. The stream flowing
+down the valley is obstructed in its course, and changed into a
+muddy lake; the rampart of rocks from which some débris still comes
+crumbling down has lost its old form; the sharpened edges point out
+the denuded cliff from which a large part of the mountain has broken
+away. In the Pyrenees, Alps, and other important ranges there are but
+few valleys where one cannot see the confused heaps of fallen rocks.
+
+Many of these catastrophes, known as the "Bergfall," have been
+recorded; and the records tell of the fearful havoc and destruction
+to life and property due to this cause. In Italy the ancient Roman
+town of Velleja was buried, about the fourth century, by the downfall
+of the mountain of Rovinazzo; and the large quantity of bones and
+coins that have been found proves that the fall was so sudden that
+the inhabitants had no time to escape.
+
+Taurentum, another Roman town, situated, it is said, on the banks
+of Lake Geneva, at the base of one of the spurs of the Dent d'Oche,
+was completely crushed in A. D. 563 by a downfall of rocks. The
+sloping heap of débris thus formed may still be seen advancing like a
+headland into the waters of the lake. A terrible flood-wave, produced
+by the deluge of stones, reached the opposite shores of the lake and
+swept away all the inhabitants. Every town and village on the banks,
+from Morges to Vevay, was demolished, and they did not begin the work
+of rebuilding till the following century. Some say, however, that the
+disaster was caused by a landslip which fell from the Grammont or
+Derochiaz across the valley of the Rhone, just above the spot where
+it flows into the Lake of Geneva. Hundreds of such falls have taken
+place within the Alps and neighbouring mountains within historic
+times.
+
+Two out of the five peaks of the Diablerets fell down, one in 1714
+and the other in 1749, covering the pastures with a thick layer
+of stones and earth more than three hundred feet thick, and by
+obstructing the course of the stream of Lizerne, formed the three
+lakes of Derborence. In like manner the Bernina, the Dent du Midi,
+the Dent de Mayen, and the Righi have overspread with ruin vast
+tracts of cultivated land. In Switzerland the most noted Bergfalls
+are those from the Diablerets and the Rossberg. The former mountain
+is a long flattish ridge with several small peaks, overhanging very
+steep walls of rock on either side. These walls are composed of
+alternating beds of limestone and shale. Hence it is easily perceived
+that we have here conditions favourable for landslips, because if
+anything weakens one of these beds of shale the overlying mass
+might be inclined to break away. The fall in the year 1714, already
+referred to, was a very destructive one.
+
+  [Illustration: THE MATTERHORN. FROM A PHOTOGRAPH BY MR. DONKIN.]
+
+   "For two whole days previously loud groaning had been heard to
+   issue from the mountain, as though some imprisoned spirit were
+   struggling to release himself, like Typhoeus from under Etna;
+   then a vast fragment of the upper part of the mountain broke
+   suddenly away and thundered down the precipices into the valley
+   beneath. In a few minutes fifty-five châlets, with sixteen
+   men and many head of cattle, were buried for ever under the
+   ruins. One remarkable escape has indeed been recorded, perhaps
+   the most marvellous ever known. A solitary herdsman from the
+   village of Avent occupied one of the châlets which were buried
+   under the fallen mass. Not a trace of it remained; his friends
+   in the valley below returned from their unsuccessful search,
+   and mourned him as dead. He was, however, still among the
+   living; a huge rock had fallen in such a manner as to protect
+   the roof of his châlet, which, as is often the case, rested
+   against a cliff. Above this, stones and earth had accumulated,
+   and the man was buried alive. Death would soon have released
+   him from his imprisonment, had not a little rill of water
+   forced its way through the débris and trickled into the châlet.
+   Supported by this and by his store of cheese, he lived three
+   months, labouring all the while incessantly to escape. Shortly
+   before Christmas he succeeded, after almost incredible toil, in
+   once more looking on the light of day, which his dazzled eyes,
+   so long accustomed to the murky darkness below, for a while
+   could scarcely support. He hastened down to his home in Avent,
+   and knocked at his own door; pale and haggard, he scarcely
+   seemed a being of this world. His relations would not believe
+   that one so long lost could yet be alive, and the door was shut
+   in his face. He turned to a friend's house; no better welcome
+   awaited him. Terror seized upon the village; the priest was
+   summoned to exorcise the supposed demon; and it was not till he
+   came that the unfortunate man could persuade them that he was
+   no spectre, but flesh and blood."[14]
+
+  [14] Bonney.
+
+The valley is still a wild scene of desolation, owing to the
+enormous masses of stones of every shape and size with which its bed
+is filled.
+
+In September of the year 1806, the second fall of the mountain
+Rossberg took place, after a wet summer. It is underlaid by beds of
+clay which, when water penetrates, are apt to give way. The part
+which fell was about three miles long and 350 yards wide and 33 yards
+thick. In five minutes one of the most fertile valleys in Switzerland
+was changed to a stony desert. Three whole villages, six churches,
+120 houses, 200 stables or châlets, 225 head of cattle, and much land
+were buried under the ruins of the Rossberg; 484 persons lost their
+lives. Some remarkable escapes are recorded.
+
+In the year 1618 the downfall of Monte Conto buried 2,400 inhabitants
+of the village of Pleurs, near Chiavenna. Excavation among the
+ruins was subsequently attempted, but a few mangled corpses and a
+church-bell were all that could be reached.
+
+Geologically these phenomena, appalling as they are from the human
+point of view, possess a certain interest, and their effects deserve
+to be studied.
+
+There is yet another danger to which dwellers in mountains are
+occasionally exposed; namely, the earthquake. It seems to be an
+established fact that earthquake shocks are more frequent in
+mountainous than in flat countries. The origin of these dangerous
+disturbances of the earth's crust has not yet been fully explained.
+They are probably caused in various ways; and it is very likely
+that the upheaval of mountain-chains is one of the causes at work.
+Earthquakes have for many years been carefully studied by scientific
+men, and some valuable discoveries have been made. Thus we find that
+they are more frequent in winter than summer, and also happen more
+often by night than by day. Day and night are like summer and winter
+on a small scale, and so we need not be surprised at this discovery.
+Some have maintained that there is a connection between earthquakes
+and the position of the moon; while others consider that the state
+of the atmosphere also exerts an influence, and that earthquakes
+are connected with rainy seasons, storms, etc. Earthquakes are very
+often due to volcanic eruptions, but this is not always the case (see
+chapter vi., page 199).
+
+
+
+
+CHAPTER IV.
+
+MOUNTAIN PLANTS AND ANIMALS.
+
+   The high hills are a refuge for the wild goats, and so are the
+   stony rocks for the conies.--_Psalm civ. 18._
+
+
+There must be few people who have neither seen nor heard of the
+beauty and exquisite colours of Alpine[15] flowers. They are first
+seen on the fringes of the stately woods above the cultivated
+land; then in multitudes on the sloping pastures with which many
+mountain-chains are robed, brightening the verdure with innumerable
+colours; and higher up, where neither grass nor loose herbage can
+exist, among the slopes of shattered fragments which roll down from
+the mountain-tops,--nay, even amidst the glaciers,--they gladden the
+eye of the traveller and seem to plead sweetly with the spirits of
+destruction. Alpine plants fringe the vast hills of snow and ice of
+the high hills, and sometimes have scarcely time to flower and ripen
+a few seeds before being again covered by their snowy bed. When
+the season is unfavourable, numbers of them remain under the snow
+for more than a year; and here they safely rest, unharmed by the
+alternations of frost and biting winds, with moist and springlike
+days. They possess the great charm of endless variety of form and
+colour, and represent widely separated divisions of the vegetable
+kingdom; but they are all small and low-growing compared to their
+relatives grown in the plains, where the soil is richer and the
+climate milder. Among them are tiny orchids quite as interesting
+in their way as those from the tropics; liliputian trees, and a
+tree-like moss (_Lycopodium dendroideum_) branching into an erect
+little pyramid as if in imitation of a mountain pine; ferns that peep
+cautiously from narrow rocky crevices as if clinging to the rock
+for shelter from the cold blasts; bulbous plants, from lilies to
+bluebells; evergreen shrubs, perfect in leaf and blossom and fruit,
+yet so small that one's hat will cover them; exquisite creeping
+plants spreading freely along the ground, and when they creep over
+the brows of rocks or stones, draping them with curtains of colour
+as lovely as those we see in the forests; numberless minute plants
+scarcely larger than mosses, mantling the earth with fresh green
+carpets in the midst of winter; succulent plants in endless variety;
+and lastly the ferns, mosses, and lichens which are such an endless
+source of pleasure and delight to the traveller. In short, Alpine
+vegetation presents us with nearly every type of plant life of
+northern and temperate climes, chastened in tone and diminished in
+size.
+
+  [15] The word "Alpine" is used in a general sense to denote the
+  vegetation that grows naturally on the most elevated regions of
+  the earth; that is, on all high mountains, whether they rise up
+  in hot tropical plains or in cooler northern pastures.
+
+It is not difficult to account for the small size of these plants;
+for in the first place we cannot expect a large or luxuriant growth
+where the air is cold, the soil scanty, and the light of the sun
+often obscured by clouds, and where the changes of temperature are
+rapid,--which is very unfavourable to most plants. Again, in the
+close struggle for existence which takes place on the plains and low
+tree-clad hills, the smaller forms of plant life are often overrun by
+trees, trailing plants, bushes, and vigorous herbs; but where these
+cannot find a home, owing to the severity of the winter and other
+causes, the little Alpine plants, covered up by snow in the winter,
+can thrive abundantly. And lastly, like the older and conquered races
+of men who have been driven to the hills (see chap. i., p. 28) and
+find shelter there, so there are both plants and animals living in
+the mountains which man will not suffer to live in the plain where
+he grows his crops, pastures his cattle, or builds his cities. We
+would also venture to suggest that possibly some plants have been
+ousted from plains by newer and more aggressive types, which came and
+took their place. If so, vegetable life would afford an illustration
+of a process which has so often taken place in human history. This
+is only a speculation, but still it might be worth following up. If
+Alpine plants, or any considerable number of them, could be shown
+to belong to more ancient types, such as flourished in the later
+geological periods, that would afford some evidence in favour of
+the idea. Whether this is so or not, plant life on the mountains is
+almost entirely protected from the destroying hands of men with their
+ploughs and scythes, as well as from many grazing animals. As Mr.
+Ruskin quaintly says:
+
+   "The flowers which on the arable plain fell before the plough
+   now find out for themselves unapproachable places, where year
+   by year they gather into happier fellowship and fear no evil."
+
+It is clear that the climate of a mountainous region determines the
+character of the vegetation. Now, the climate will be different in
+different parts of a mountain-range, and will depend upon the height
+above the sea and other causes.[16] Some writers upon this subject
+have attached too much importance to absolute height above the sea,
+as though this were the only cause at work. It is a very important
+cause, no doubt, but there are others which also have a great
+influence, such as the position of each locality with respect to the
+great mountain masses, the local conditions of exposure to the sun
+and protection from cold winds, or the reverse. However, in spite of
+local irregularities there are in the Alps certain broad zones or
+belts of vegetation which may be briefly described as follows:--
+
+  [16] The following remarks are largely taken from the
+  Introduction to Ball's well-known "Alpine Guide."
+
+1. _The Olive region._--This region curiously illustrates what has
+just been said about other causes besides height influencing the
+climate and vegetation. For along the southern base of the Alps, the
+lower slopes and the mouths of the valleys have a decidedly warmer
+climate than the plains of Piedmont and Lombardy. Thus, while the
+winter climate of Milan is colder than that of Edinburgh, the olive
+can ripen its fruit along the skirts of the mountain region, and
+penetrates to a certain distance towards the interior of the chain
+along the lakes and the wider valleys of the Southern Alps. Even up
+the shores of the Lake of Garda, where the evergreen oak grows, the
+olive has become wild. The milder climate of the Borromean Islands,
+and some points on the shores of the Lago Maggiore, will permit many
+plants of the warmer temperate zone to grow; while at a distance of a
+few miles, and close to the shores of the same lake, but in positions
+exposed to the cold winds from the Alps, plants of the Alpine region
+grow freely, and no delicate perennials can survive the winter. The
+olive has been known to resist a temperature of about 16° F. (or
+16° below the freezing point of water), but is generally destroyed
+by a less degree of cold. It can only be successfully cultivated
+where the winter frosts are neither long nor severe, where the mean
+temperature of winter does not fall below 42° F., and a heat of 75°
+F. during the day is continued through four or five months of the
+summer and autumn.
+
+2. _The Vine region._--The vine, being more tolerant of cold than the
+olive, can grow at a higher level; and so the next zone of vegetation
+in the Alps may be called "the Vine region." But to give tolerable
+wine it requires at the season of ripening of the grape almost as
+much warmth as the olive needs. Vines can grow in the deeper valleys
+throughout a great part of the Alpine chain, and in favourable
+situations up to a considerable height on their northern slopes.
+On the south side, although the limit of perpetual snow is lower,
+the vine often reaches near to the foot of the greater peaks. But
+the fitness of a particular spot for the production of wine depends
+far more on the direction of the valley and of the prevailing winds
+than on the height. And so it happens that in the Canton Valais, the
+Valley of the Arc in Savoy, and some others on the north side of the
+dividing range, tolerable wine is made at a higher level than in the
+valleys of Lombardy, whose direction allows the free passage of the
+keen northern blasts. It is a curious fact that in the Alps the vine
+often resists a winter temperature which would kill it down to the
+roots in the low country; and we must explain it by the protection
+of the deep winter snow. Along with the vine many species of wild
+plants, especially annuals, characteristic of the flora of the south
+of Europe, show themselves in the valleys of the Alps.
+
+3. _The Mountain region, or region of deciduous trees._--Many writers
+take the growth of corn as the characteristic of the colder temperate
+zone, corresponding to what has been called the mountain region of
+the Alps. But so many varieties, all with different requirements,
+are in cultivation, that it is impossible to take the growth of
+cereals in general as marking clearly any natural division of the
+surface. A more natural limit is marked by the presence of deciduous
+trees (trees which shed their leaves). Although the oak, beech, and
+ash do not exactly reach the same height, and are not often seen
+growing side by side in the Alps, yet their upper limit marks pretty
+accurately the transition from a temperate to a colder climate that
+is shown by a general change in the wild, herbaceous vegetation. The
+lower limit of this zone is too irregular to be exactly defined, but
+its upper boundary is about 4,000 feet on the cold north side of the
+Alps, and often rises to 5,500 feet on the southern slopes, which of
+course get more sunshine and warmth. The climate of this region is
+favourable to the growth of such trees as the oak, beech, and ash,
+but it does not follow that we should see them there in any great
+numbers at the present time; for it is probable that at a very early
+date they were extensively destroyed for building purposes, and to
+clear space for meadow and pasture land, so that with the exception
+of the beech forests of the Austrian Alps, there is scarcely a
+considerable wood of deciduous trees to be seen anywhere in the
+chain. In many districts where the population is not too dense, the
+pine and Scotch fir have taken the place of the oak and beech, mainly
+because the young plants are not so eagerly attacked by goats, the
+great destroyers of trees.
+
+4. _The region of Coniferous trees._--Botanically this region is
+best distinguished by the prevalence of coniferous trees, forming
+vast forests, which if not kept down by man (and by goats) would
+cover the slopes of the Alps. The prevailing species are the common
+fir and the silver fir. In districts where granite abounds, the
+larch flourishes and reaches a greater size than any other tree.
+Less common are the Scotch fir and the arolla, or Siberian fir.
+In the Eastern Alps the dwarf pine becomes conspicuous, forming
+a distinct zone on the higher mountains above the level of other
+firs. The pine forests play a most important part in the natural
+economy of the Alps; and their preservation is a matter of very great
+importance to the future inhabitants. But in some places they have
+been considerably diminished by cutting. This has especially happened
+in the neighbourhood of mines; and in consequence the people of the
+unfrequented communes have become so alive to this that some jealousy
+is felt of strangers wandering among the mountains, lest they should
+discover metals and cause the destruction of the woods. Their fears
+are not unreasonable; for the forests, besides exerting a good deal
+of influence on rainfall and climate, form natural defences against
+the rush of the spring avalanches (see chapter iii., page 93). It is
+recorded that after the war of 1799, in which many of those near the
+St. Gothard Pass were destroyed, the neighbouring villages suffered
+terribly from this scourge. Hence the laws do not allow of timber
+being cut in certain forests called "Bannwalde;" and in most places
+the right of felling trees is strictly regulated, and the woods are
+under the inspection of officials.
+
+In spots high up among the mountains, to which access is difficult,
+the timber is converted into charcoal, which is then brought down
+in sacks by horses and mules. There are two ways in which timber is
+conveyed down from the forest: either it is cut up into logs some
+five feet long, and thrown into a neighbouring torrent, which brings
+it down over cliff and gorge to the valley below; or else trough-like
+slides are constructed along the mountain-sides, down which the
+trunks themselves are launched.
+
+It is this region of coniferous trees which mainly determines the
+manner of life of the population of the Alps. In the month of May the
+horned cattle, having been fed in houses during the winter (as they
+are in the Scotch Highlands, where the cowsheds are called "byres"),
+are led up to the lower pastures. The lower châlets, occupied in May
+and part of June, generally stand at about the upper limit of the
+mountain region. Towards the middle or end of June the cattle are
+moved up to the chief pastures, towards the upper part of the region
+of coniferous trees, where they usually remain for the next two or
+three months. But there are some available pastures still higher up,
+and hither some of the cattle are sent for a month or more.
+
+5. _The Alpine region._--This is the zone of vegetation extending
+from the upper limit of trees to where permanent masses of snow first
+make their appearance; so that where the trees cease, the peculiar
+Alpine plants begin; but we still find shrubs, such as the common
+rhododendron, Alpine willow, and the common juniper, which extend
+up to, and the latter even beyond, the level of perpetual snow. The
+limits of this interesting and delightful botanical region may be
+fixed between 6,000 and 8,000 feet above the sea, and at least 1,000
+feet higher on the south slopes of the Alps, which get more sunshine.
+It is used to some extent for pasture; and in Piedmont it is not
+uncommon to find châlets at the height of 8,500 feet, and vegetation
+often extends freely up to 9,500 feet. Here and there, at levels
+below this zone, many Alpine species may be found, either transported
+by accident from their natural home, or finding a permanent
+refuge in some cool spot sheltered from the sun, and moistened by
+streamlets descending from the snow region. But it is chiefly here
+that those delightful flowers grow which make the Alps like a great
+flower-garden,--great anemones, white and sulphur-coloured; gentians
+of the deepest blue, like the sky overhead; campanulas, geums, Alpine
+solanellas, and forget-me-nots; asters, ox-eyed daisies, pale pink
+primulas, purple heartsease, edelweiss, saxifrages, yellow poppies,
+Alpine toad-flax, monkshood, potentilla, and others too numerous to
+mention. Says Professor Bonney,--
+
+   "Who cannot recall many a happy hour spent in rambling from
+   cluster to cluster on the side of some great Alp?--the scent of
+   sweet herbage or of sweeter daphne perfuming the invigorating
+   air, the melody of the cattle-bells borne up from some far-off
+   pasture, while the great blue vault of heaven above seems
+   reflected in the gentian clusters at his feet. The love of
+   flowers seems natural to almost every human being, however
+   forlorn his life may have been, however far it may have missed
+   its appointed mark. It may well be so; they at least are fresh
+   and untainted from their Maker's hand; the cry of 'Nature red
+   in tooth and claw' scarce breaks their calm repose. Side by
+   side they flourish without strife; none 'letteth or hindereth
+   another,' yet so tender and delicate, doomed to fade all too
+   soon, a touch of sadness is ever present to give a deeper
+   pathos to our love."
+
+6. _The Glacial region._--This comprehends all that portion of the
+Alps that rises above the limit of perpetual snow. But a word of
+explanation is necessary. The highest parts of the Alps are not
+covered by one continuous sheet of snow; otherwise we should never
+see any peaks or crags there. Some are too steep for the snow to
+rest upon them, and therefore remain bare at heights much greater
+than the so-called "limit of perpetual snow," and that limit varies
+considerably. Still this term has a definite meaning when rightly
+understood. Leaving out of account masses of snow that accumulate in
+hollows shaded from the sun, the "snow-line" is fairly even, so that
+on viewing an Alpine range from a distance, the larger patches and
+fields of snow on adjoining mountains, with the same aspect, are seen
+to maintain a pretty constant level.
+
+  [Illustration: ON A GLACIER.]
+
+Vegetation becomes scarce in this region, not, as commonly supposed,
+because Alpine plants do not here find the necessary conditions for
+growth, but simply for want of soil. The intense heat of the direct
+rays of the sun (see chapter iii., pages 76-77) compensates for the
+cold of the night; and it is probable that the greater allowance of
+light also stimulates vegetable life. But all the more level parts
+are covered with ice or snow; and the higher we ascend, the less the
+surface remains bare, with the exception of the projecting rocks
+which usually undergo rapid destruction and breaking up from the
+freezing of whatever water finds its way into their fissures.
+
+Nevertheless, many species of flowering plants have been found even
+at the height of eleven thousand feet.
+
+It is in this region that plants are found whose true home is in the
+arctic regions (see chapter ii., pages 64-65).
+
+For the sake of those who love ferns, lycopods, and other cryptogamic
+or flowerless plants, a few words may be said here. Of the
+polypodies, the beech fern and oak fern are generally common, so is
+the limestone polypody in places where limestone occurs. Another
+species (_P. alpestre_) very like the lady fern grows plentifully
+in many places. The parsley fern, familiar to the botanist in Wales
+and other parts of Great Britain, is common, especially on the
+crystalline rocks, and ascends to above seven thousand feet. The
+holly fern is perhaps the most characteristic one of the higher Alps.
+It is abundant in almost every district from the Viso to the Tyrol,
+ranging from about five thousand feet to nearly eight thousand feet.
+The finest specimens are to be found in the limestone districts.
+Nestling down in little channels worn out of the rock, it shoots out
+great fronds, often more than eighteen inches long, which are giants
+compared to the stunted specimens seen on rockwork in English gardens.
+
+_Asplenium septentrionale_ is very common in most of the districts
+where crystalline rocks abound. The hart's tongue is hardly to be
+called a mountain fern. The common brake is confined to the lower
+slopes.
+
+_Cistopteris fragillis_ and _C. dentata_ are common, and the more
+delicate _C. Alpina_ is not rare. The noble _Osmunda regalis_ keeps
+to the warmer valleys. The moonwort abounds in the upper pastures.
+
+The club-mosses (_Lycopodium_), which are found in Great Britain,
+are common in most parts of the Alps, especially the _L. selago_,
+which grows almost up to the verge of the snows. Lower down is the
+delicate _L. velveticum_, which creeps among the damp mosses under
+the shade of the forest. Many of the smaller species stain with
+spots of crimson, orange, and purple the rocks among the snowfields
+and glaciers, and gain the summits of peaks more than eighteen
+thousand feet above the sea, reaching even to the highest rocks in
+the Alpine chain. For the sake of readers who are not familiar with
+that wonderful book, "Modern Painters," we will quote some exquisite
+passages on lichens and mosses, full of beautiful thoughts:--
+
+  "We have found beauty in the tree yielding fruit and in the herb
+  yielding seed. How of the herb yielding no seed,--the fruitless,
+  flowerless[17] lichen of the rock?
+
+    [17] Flowerless in the ordinary, not the botanical sense.
+
+  "Lichens and mosses (though these last in their luxuriance are deep
+  and rich as herbage, yet both for the most part humblest of the
+  green things that live),--how of these? Meek creatures!--the first
+  mercy of the earth, veiling with trusted softness its dintless rocks,
+  creatures full of pity, covering with strange and tender honour
+  the scarred disgrace of ruin, laying quiet finger on the trembling
+  stones to teach them rest. No words that I know of will say what
+  these mosses are; none are delicate enough, none perfect enough, none
+  rich enough. How is one to tell of the rounded bosses of furred and
+  beaming green; the starred divisions of rubied bloom, fine-filmed, as
+  if the Rock Spirits could spin porphyry as we do grass; the traceries
+  of intricate silver, and fringes of amber, lustrous, arborescent,
+  burnished through every fibre into fitful brightness and glossy
+  traverses of silken change, yet all subdued and pensive, and framed
+  for simplest, sweetest offices of grace? They will not be gathered,
+  like the flowers, for chaplet or love token; but of these the wild
+  bird will make its nest and the wearied child his pillow.
+
+  "And as the earth's first mercy, so they are its last gift to us.
+  When all other service is vain, from plant and tree the soft mosses
+  and grey lichen take up their watch by the headstone. The woods, the
+  blossoms, the gift-bearing grasses, have done their parts for a time,
+  but these do service for ever. Tree for the builder's yard--flowers
+  for the bride's chamber--corn for the granary--moss for the grave.
+
+  "Yet as in one sense the humblest, in another they are the most
+  honoured of the earth-children; unfading as motionless, the worm
+  frets them not and the autumn wastes not. Strong in lowliness, they
+  neither blanch in heat nor pine in frost. To them, slow-fingered,
+  constant-hearted, is entrusted the weaving of the dark, eternal
+  tapestries of the hills; to them, slow-pencilled, iris-dyed, the
+  tender framing of their endless imagery. Sharing the stillness of
+  the unimpassioned rock, they share also its endurance; and while the
+  winds of departing spring scatter the white hawthorn blossom like
+  drifted snow, and summer dims on the parched meadow the drooping
+  of its cowslip,--gold far above, among the mountains, the silver
+  lichen-spots rest, star-like, on the stone; and the gathering
+  orange-stain upon the edge of yonder western peak reflects the
+  sunsets of a thousand years."
+
+Alpine and arctic plants are met with in Great Britain, but Scotland
+has a much more extensive arctic-Alpine flora than England, Wales,
+or Ireland, the reason being the greater altitude of its mountains.
+The combined flora of the United Kingdom contains only ninety-one
+species of arctic-Alpine plants, and of these eighty-eight--that is,
+all but three--are natives of Scotland. Of these three the first is
+a gentian (_Gentiana verna_), which is to be found on the hills of
+West Yorkshire, Durham, Westmoreland, and other parts. It comes from
+the Alps. The second is _Lloydia serotina_,--a small bulbous plant
+with white flowers, which is found on the hills of Carnarvonshire,
+in Wales. The third, well known in English gardens, is London pride
+(_Saxifraga umbrosa_), which is only to be found on the southwest
+Irish hills.
+
+Of the ninety-one arctic-Alpine species, just about half are also
+natives of England and Wales, but only twenty-five belong to Ireland.
+If we examine the lists of the flora of Arctic Europe we find that
+all these, except about six, are found in arctic regions; and if we
+travel farther north till we come actually to polar regions, we find
+nearly fifty of these species growing there near the sea-level. The
+Grampian Mountains are the chief centre of the Scottish arctic-Alpine
+flora. The two principal localities for such flowers in that range
+are the Breadalbane Mountains in Perthshire, and the Cænlochan and
+Clova Mountains of Forfarshire. There are also a goodly number on the
+mountains of the Braemar district.
+
+The history of the arctic-Alpine flora of Europe is a very
+interesting one. These plants, whose true home is in the arctic
+regions, living high up on the mountains of Europe, give unmistakable
+evidence of a time, very far back, when Northern Europe was overrun
+by glaciers and snowfields so as to resemble in appearance and in
+climate the Greenland of the present day. This period is known to
+geologists as the "Great Ice Age." The moraines of glaciers, ice-worn
+rock surfaces, and other unmistakable signs may be well seen in
+many parts of Great Britain. How long ago this took place we cannot
+say; but judging from the considerable changes in geography which
+have undoubtedly taken place since then, we must conclude that many
+thousands of years, perhaps two hundred thousand, have intervened
+between this period and the present time.
+
+When arctic conditions prevailed over this wide area, the plants
+and animals which now live in arctic latitudes flourished in Great
+Britain; but as the climate gradually became more genial, and the
+snow and ice melted, the plants and animals mostly retreated to
+their northern home. A certain number doubtless became extinct; but
+others took to the highest parts of the mountains, where snow and
+ice abound; and there they remain to the present day, separated from
+their fellows, but still enjoying the kind of climate to which they
+have always been accustomed, and testifying to the wonderful changes
+which have taken place since the mammoth, whose bones are found
+embedded in our river-gravels, wandered over the plains of Northern
+Europe.
+
+
+_Animal Life._
+
+The rocky fastnesses of the Alps still afford a home to some of the
+larger wild animals which in other parts of Europe have gradually
+disappeared with the advance of civilisation. During the latter part
+of the "Stone Age," long before history was written, when men used
+axes, hammers, arrow-heads, and other implements of stone, instead of
+bronze or iron, Switzerland was inhabited by animals which are not to
+be seen now. The gigantic urus (_Bos primigenius_), which flourished
+in the forests of the interior during this prehistoric human period,
+and gave its name to the canton of Uri, has become extinct. The marsh
+hog was living during the period of the Swiss lake-dwellers. These
+people made their houses on piles driven in near the shore, and were
+acquainted with the use of bronze, and therefore later than the men
+of the "Stone Age." The remains of these strange dwelling-places
+have been discovered in several places, as well as many articles of
+daily use. The marsh hog has disappeared; and its place is taken by
+the wild boar and domestic hog, which afford sport and food to the
+present population. But taking Switzerland as it now is, we will say
+a few words about the more interesting forms of animal life dwelling
+in the Alps, beginning with those which are highest in the animal
+kingdom. Chief among these is the brown bear, still occasionally
+found, but it is exceedingly rare, except in the Grisons and in the
+districts of the Tyrol and Italy bordering on the canton, where it
+still carries on its ravages.[18] Some also believe that it still
+lingers in the rocky fastnesses of the Jura Mountains, to the east of
+the Alps. There is properly only one species of bear in Switzerland,
+but the hunters generally speak of three,--the great black, the
+great grey, and the small brown. The second of these is merely an
+accidental variety of the first; but between the grey and the small
+brown bears there is a good deal of difference. They assert that
+the black bear is not only considerably larger than the brown, but
+is also different in its habits. It is less ferocious and prefers a
+vegetable diet,--feeding on herbs, corn, and vegetables, with the
+roots and branches of trees. It has a way of plundering bee-hives and
+also ants' nests; it delights in strawberries and all kinds of fruit,
+plundering the orchards, and even making raids on the vineyards,
+but always retreating before dawn. As a rule it does not attack
+human beings. The brown bear is much more formidable, prowling by
+night about the sheepfolds, and causing the sheep by their fright to
+fall down precipices. Goats, when alarmed, leap on the roofs of the
+châlets, and bleat, in order to arouse the shepherds; so that when
+Bruin rears himself up against the wall he often meets his death.
+There are many stories on record of fierce fights for life between
+man and bear. The bear passes the winter in a torpid state, and eats
+little or nothing then.
+
+  [18] We are again indebted to Professor Bonney's "Alpine Regions
+  of Switzerland" for the information here given.
+
+The wolf, though still lingering in several lonely parts of the
+Alps, is rapidly becoming rare. It is most frequent in the districts
+about the Engadine and in the Jura Mountains. Only in winter-time,
+when hard pressed by hunger, does it approach the haunts of man. It
+takes almost any kind of prey it can get,--foxes, hares, rats, mice,
+birds, lizards, frogs, and toads. Sheep and goats are its favourite
+prey. The wolf is an affectionate parent, and takes his turn in
+looking after the nurslings, which is a necessary precaution, as his
+friends and relations have a way of eating up the babies.
+
+The fox is common in many parts of the Alps, but not often seen
+by travellers. Instead of taking the trouble to burrow, he
+frequently manages by various cunning devices to take possession
+of a badger's hole. As Tschudi quaintly observes, "He has far too
+much imagination and poetic sentiment to like so monotonous and
+laborious an occupation as burrowing." Like the wolf, the mountain
+fox eats whatever he can catch, even beetles, flies, and bees. Those
+in the valleys live more luxuriously than their relations on the
+mountains,--plundering bee-hives and robbing orchards. As it was in
+Judæa in the days of Solomon, so it is now in Switzerland among the
+vineyards; and a peasant might well say, "Take us the foxes, the
+little foxes that spoil the vineyards."
+
+The lynx is only occasionally found in the Alps, which is fortunate
+for the shepherds, for they can play terrible havoc with the sheep.
+
+Wild-cats still linger in the most unfrequented parts. Their fur is
+valuable, and the flesh is sometimes eaten. The badger is far from
+common, though rarely seen by day. It is very cunning in avoiding
+traps, and so is generally either dug out of its hole drawn by
+dogs, or pulled out by a pole with nippers or a hook at the end.
+Passing on to less ferocious beasts, we find the otter common along
+the borders of rivers and lakes. The polecat, weasel, and stoat
+are often too abundant for keepers of poultry. The squirrel is
+common enough in the forests, but varies greatly in colour. It is
+doubtful whether the beaver still lingers by some lonely Alpine
+stream. It is last mentioned in a list of Swiss mammals, published
+in 1817, as found, though rarely, in some lonely spots. Rabbits are
+common, but hares rather scarce; of these there are, as in Scotland,
+two varieties,--the brown hare, which is seldom found at heights
+greater than four thousand to five thousand feet, and the blue
+hare, which ranges up to nine thousand feet. The latter changes
+colour: its fur in summer is of a dull bluish-grey, and in winter it
+becomes perfectly white, and so affords a striking illustration of
+"protective mimicry," for with snow lying on the ground it would be
+very hard to see the creature.
+
+The marmot is common in all the higher Alpine regions. These
+interesting little creatures are very watchful, and easily scent
+danger. When an intruder approaches, a sentinel marmot utters a
+long shrill whistle, which is often repeated two or three times,
+and then they all make for their burrows; but it is not easy to
+distinguish them from the grey rocks among which they live. The fur
+is a yellowish or brownish grey, with black on the head and face,
+and a little white on the muzzle; the tail is short and bushy with a
+tipping of black. They have different quarters for summer and winter.
+The summer burrows are in the belt of rough pasture between the
+upper limits of trees and the snows; towards the end of autumn they
+come down to the pastures which the herdsmen have just abandoned
+and there make their winter burrows, which are much larger than the
+summer ones. Like rabbits, they frequently make a bolt-hole, by which
+they may escape from an intruder. In winter the holes are plugged up,
+and the marmots, rolling themselves up in a ball, go to sleep for six
+months or more. Sometimes hunters dig them out; but so soundly do
+they sleep that, according to De Saussure, they may often be taken
+out, placed in the game-bag, and carried home without being aroused.
+They wake up about April.
+
+The chamois, a very favourite subject with the wood-carvers, is the
+only member of the antelope family in Western Europe; it is found
+in almost every part of the Alps, but is now much rarer than it was
+formerly. A full-grown chamois in good condition weighs about sixty
+pounds. The hair is thick, and changes colour with the season, being
+a red yellowish-brown in summer and almost black in winter. The
+horns, which curve backwards, rise from the head above and between
+the eyes to a height which rarely exceeds seven inches. When the
+kid is about three months old, the horns make their appearance, and
+at first are not nearly as hook-shaped as they afterwards become.
+When full-grown, it stands at the shoulder about two feet from the
+ground. The hind-legs being longer than the fore-legs, its gait is
+awkward on level ground, but they are admirably suited for mountain
+climbing. When at full speed, it can check itself almost instantly,
+and can spring with wonderful agility. Its hoofs are not well adapted
+for traversing the ice, and therefore it avoids glaciers as far as
+possible. Having a great fear of concealed crevasses, it is very
+shy of venturing on the upper part of a glacier; and the tracks
+which it leaves in these places often show by their windings and
+sudden turnings that the animal has exercised great caution. And so
+travellers often use this as a useful clue to getting safely over
+a glacier. Its agility is something extraordinary. It can spring
+across chasms six or seven yards wide, and "with a sudden bound leap
+up the face of a perpendicular rock, and merely touching it with its
+hoofs, rebound again in an opposite direction to some higher crag,
+and thus escape from a spot where, without wings, egress seemed
+impossible. When reaching upwards on its hind-legs, the fore-legs
+resting on some higher spot, it is able to stretch to a considerable
+distance, and with a quick spring bring up its hind-quarters to a
+level with the rest of the body, and with all four hoofs together,
+stand poised on a point of rock not broader than your hand."[19] The
+chamois feed on various mountain herbs, and on the buds and sprouts
+of the rhododendron and latschen (a pine). At night they couch among
+the broken rocks high upon the mountains, descending at daybreak
+to pasture, and retreating, as the heat increases, towards their
+fastnesses. When winter comes, they are forced down to the higher
+forests, where they pick up a scanty subsistence from moss, dead
+leaves, and the fibrous lichen which hangs in long yellowish-grey
+tufts from the fir-trees and bears the name of "chamois-beard."
+While browsing on this, they sometimes get their horns hooked in a
+bough, and so, being unable to disentangle themselves, perish with
+hunger. The senses of hearing, smell, and sight are exceedingly
+acute; so that the hunter must exercise all his craft to approach
+the animals. Pages might be filled with the hair-breadth escapes and
+fearful accidents which have befallen hunters; and yet they find the
+pursuit so fascinating that nothing will induce them to abandon it. A
+young peasant told the famous De Saussure (the pioneer of Alpine
+explorers) that though his father and grandfather before him had met
+their death while out on the hunt, not even the offer of a fortune
+would tempt him to change his vocation. The bag which he carried with
+him he called his winding-sheet, because he felt sure he would never
+have any other. Two years afterwards he was found dead at the foot of
+a precipice.
+
+  [19] Bonar on Chamois-hunting in Bavaria.
+
+The bouquetin, or steinbock, once abundant throughout the greater
+part of the Alps, is now confined to certain parts where it is
+preserved by the King of Italy. De Saussure observes that in his
+time they had ceased to be found near Chamouni. Its whole build is
+remarkably strong, giving it quite a different appearance from the
+slender and graceful chamois.
+
+  [Illustration: RED DEER. AFTER ANSDELL.]
+
+The roe, the fallow deer, and the red deer have, it is said, quite
+disappeared from the French and Swiss Alps, but all of them occur in
+the Bavarian and Austrian highlands. They frequent the forests which
+clothe the lower slopes, and do not often wander into the more rocky
+districts. The wild boar only now and then appears across the Rhine,
+although it is common in the Subalpine forests farther east; but we
+can hardly consider it a true Alpine quadruped.
+
+Passing on to the birds which frequent the Alps, we must first notice
+the bearded vulture, the lämmergeier of the Germans, which once was
+common, but now only holds its own here and there in some lonely
+mountain fastness. Although preferring living prey to carrion, still
+in many ways it is closely allied to the true vulture. The upper part
+of the body is a greyish-brown hue, the under side white, tinged with
+reddish brown. The nest, built on a high ledge of rock, consists of
+straw and fern, resting on sticks, on which are placed branches lined
+with moss and down. It is a rare thing for the traveller to obtain
+a view of this monarch of the Alpine birds. Like the true vulture,
+its digestive powers are marvellous. According to Tschudi ("Les
+Alpes"), the stomach of one of these birds was found to contain five
+fragments of a cow's rib, a mass of matted wool and hair, and the
+leg of a kid perfect from the knee downwards. Another had bolted a
+fox's rib fifteen inches long, as well as the brush, besides a number
+of bones and other indigestible parts of smaller animals, which
+were slowly being eaten away by the gastric juice. Sheep, goats,
+full-grown chamois, and smaller quadrupeds are eagerly devoured by
+this voracious bird. It is said to be bold enough to attack a man,
+when it finds him asleep or climbing in any dangerous place. Tschudi,
+in his book on the Alps, gives several instances of young children
+being carried off. One of these happened in the Bernese Oberland, as
+follows: Two peasants, making hay upon the pastures, had taken with
+them their daughter Anna, a child about three years old. She quickly
+fell asleep on the turf near the hay châlet; so the father put his
+broad-brimmed hat over her face, and went to work some little way
+off. On his return with a load of hay the child was gone; and a brief
+search showed that she was nowhere near. Just at this time a peasant
+walking along a rough path in the glen was startled by the cry of a
+child, and going towards the place whence it came, saw a lämmergeier
+rise from a neighbouring summit and hover for some time over a
+precipice. On climbing thither in all haste, he found the child
+lying on the very brink. She was but little injured; some scratches
+were found on her hands and on the left arm, by which she had been
+seized; and she had been carried more than three quarters of a mile
+through the air. She lived to a good old age, and was always called
+the Geier-Anna, or Vulture's Annie, in memory of her escape. The
+particulars are inscribed in the registers of the parish of Habkeren.
+
+The golden eagle is not uncommon in most parts of the Alps, although
+travellers rarely obtain a near view. It is said to be very fond
+of hares, chasing and capturing them very cleverly. As in Great
+Britain, it is accused of carrying off children; but this is at least
+doubtful. The kite, buzzard and falcon are occasionally seen. There
+are at least ten species of owls, among which is the magnificent
+eagle-owl. The raven is found in the lonelier glens, and is often
+tamed. Its thieving propensities are very amusing. Alpine birds
+of prey correspond very closely with British. The jackdaw is also
+common. It would be impossible within our short limits to give
+a complete list of Swiss birds, but we may mention among others
+the nutcracker, the jay, the white-breasted swift, the wheatear,
+the common black redstart, the beautiful wall-creeper, and the
+snow-finch, which mounts to the borders of the snow. Of game-birds
+we may mention the capercailze, the black grouse, and the hazel
+grouse, all of which are common in many of the forests. The ptarmigan
+haunts the stony tracts on the borders of perpetual snow. In winter
+it turns white, and in summer greyish-brown, though a good deal of
+white remains.
+
+Pheasants and partridges cannot be said to be Alpine birds; but the
+Greek partridge may be so considered.
+
+Numbers of the mountain streams and tarns contain excellent trout,
+and most of the larger lakes are well stocked with fish. Some of the
+trout of the Swiss and Italian lakes are of great size. The pike
+frequently weigh twelve to fifteen pounds.
+
+Reptiles are not numerous. The common frog, which is said to be found
+as high as ten thousand feet above the sea, swarms in some parts of
+the Rhone Valley. Of true lizards, five species have been recognized.
+The blind-worm (which is not a snake), so common on many of our
+English heaths, is often met with. Among the true snakes we find the
+English ringed snake--quite harmless--and two adders. The common
+adder is found at a height of seven thousand feet above the sea.
+
+Lower forms of life not possessing a backbone (invertebrates) abound
+in this region; but they are far too numerous to be considered here.
+Butterflies and moths are abundant; and many of those which are rare
+in England are common in the Alps, so that the entomologist finds
+a happy hunting-ground. The beautiful swallowtail and the handsome
+apollo, coppers, painted ladies, fritillaries, and many other
+Lepidoptera thrive in these regions, and are less easily frightened
+than at home in England.
+
+
+
+
+PART II.
+
+HOW THE MOUNTAINS WERE MADE.
+
+
+
+
+Part II.
+
+HOW THE MOUNTAINS WERE MADE.
+
+
+
+
+CHAPTER V.
+
+HOW THE MATERIALS WERE BROUGHT TOGETHER.
+
+    These changes in the heavens, though slow, produce
+    Like change on sea and land.
+
+    MILTON
+
+
+Probably every mountain climber, resting for a brief space on a loose
+boulder, or seeking the shade of some overhanging piece of rock, has
+often asked himself, "How were all these rocks made?" The question
+must occur again and again to any intelligent person on visiting a
+mountain for the first time, or even on seeing a mountain-range in
+the distance. He may well ask his companions how these great ramparts
+of the earth were built up. But unless he possesses some knowledge
+of the science of geology, which tells of the manifold changes which
+in former ages have taken place on the earth, or unless, in the
+absence of such knowledge, he chance to meet with a geologist, his
+question probably remains unanswered. Such questions, however, can
+be very satisfactorily answered,--thanks to the labours of zealous
+seekers after truth, who have given the best part of their lives
+to studying the rocks which are found everywhere on the surface of
+the earth, and the changes they undergo. Geology is a truly English
+science; and Englishmen may well cherish gratefully the memories of
+its pioneers,--Hutton, Playfair, Lyell, and others, who have made the
+way so clear for future explorers.
+
+The story of the hills as written on their own rocky tablets and on
+the very boulders lying loose on their sloping sides, and interpreted
+by geologists, is a long one; for it takes us far back into the dim
+ages of the past, and like the fashionable novel, may be divided into
+three parts, or volumes. To those who follow the stony science it
+is quite as fascinating as a modern romance, and a great deal more
+wonderful, thus illustrating the force of the old saying, "Truth is
+stranger than fiction."
+
+The three parts of our story may be best expressed by the three
+following inquiries:
+
+   I. How were the materials of which mountains are built up
+   brought together and made into hard rock?
+
+   II. How were they raised up into the elevated positions in
+   which we now find them?
+
+   III. How were they carved out into all their wonderful and
+   beautiful features of crag and precipice, peaks and passes?
+
+A mountain group, with its central peak or spire, its long ridges,
+steep walls, towers, buttresses, dark hollows, and carved pinnacles
+standing out against the sky, has well been compared to a great
+and stately building such as a cathedral or a temple. Mountains
+are indeed "a great and noble architecture, giving first shelter,
+comfort, and rest, but covered also with mighty sculpture and painted
+legend;" and to many they are Nature's shrines, where men may offer
+their humble praises and prayers to the great Architect who reared
+them for His children. We have introduced this illustration because
+it will help us in our inquiry. Suppose we were standing in front of
+some great cathedral, such as Milan, with all its marble pinnacles,
+or Notre Dame, with its stately towers, or the minsters of York or
+Durham in our own country, and trying to picture to ourselves how
+it was built. No one has lived long enough to watch the completion
+of one of these great buildings; but for all that, we know pretty
+well how it was made, even by watching the builder's operations for
+a short time, or by following, as we often may, the various stages
+in the construction of a small house. So it is with Nature's work.
+We cannot, in our little lives, witness the rearing of a great
+mountain-chain, or even the carving of a single hill; but we can
+observe for ourselves the slow and continuous operations which in the
+course of thousands and thousands of years produce such stupendous
+results. We may learn how the building operations are conducted,
+though the final results will only be manifested in the far-distant
+future.
+
+But to return to our cathedral. If we try to picture to ourselves
+the long years during which it was covered with scaffolding and
+surrounded by a busy army of workers, we shall soon perceive that
+the operations may be broadly divided into three heads. _First_, we
+must inquire how the separate stones of which it is composed were
+brought together into one place, and we shall at once picture to
+ourselves groups of men working in stone-quarries,--perhaps a long
+way off,--busy with their crowbars and hammers, breaking off large
+blocks of stone, and following the natural divisions of the rock
+that their rough labour may be lessened; for all rocks will split
+more easily along certain lines than along others. Sometimes it is
+easier to follow the "bedding," or natural layers in which the rock
+was formed; at other times the "joints," or cracks subsequently
+formed as the rocky materials hardened and contracted in bulk, afford
+easier lines for the workmen to follow. Others are busily engaged in
+placing the stony blocks on trollies drawn by horses, that they may
+be borne along the roads leading from the quarry to the site of the
+future cathedral. And so, taking a bird's-eye view, we seem to see
+horses and carts slowly moving on from many a distant quarry, but
+all converging like the branches of a river to one main channel, and
+finally depositing their burdens in the stone-yard where the masons
+are at work. Perhaps bricks are partly employed, in which case we can
+easily picture to ourselves the brickyards, where some are digging
+out the soft clay, others moulding it into bricks with wooden moulds,
+while others again lay them down in rows on the ground to dry, before
+they are baked in the ovens. And when the bricks are ready for
+use, the same means of transportation are employed; and cart-loads
+of them are borne along the country roads until they so reach their
+destination.
+
+Now, all this may be summed up in the one word "transportation;"
+and we shall presently inquire how the rocky matter of which the
+mountains are built was transported.
+
+_Secondly._ We have to inquire how the bricks and stones were raised
+up. The analogy is not quite perfect in this case; for the mountains
+were raised up _en bloc_, not bit by bit and stone by stone, as in
+the case of the cathedral. Still they have been raised somehow.
+Analogies are seldom complete in every detail; but for all that, our
+illustration serves well enough, and will help us in following the
+various processes of mountain building. In these days, the raising of
+the stones is mostly effected by steam-power applied to big cranes
+and pulleys. In old days they used cranes and pulleys, but the ropes
+were pulled by hand-power. In either case the work proceeds slowly;
+and we can easily picture to ourselves the daily raising of the
+stones of which the cathedral is composed. "What were the forces
+at work which slowly raised the mountains?" This question we will
+endeavour to answer later on (see next chapter). This work may be
+included in the one word, "elevation."
+
+_And lastly._ We must inquire how the carving of the stately building
+was effected, how its pinnacles received their shape, and how all
+those lovely details received their final forms; how the intricate
+traceries of its windows were made, and the statues carved which
+adorn its solemn portals. This question is easily answered, for we
+are all more or less familiar with what goes on in a stone-mason's
+yard. Under those wooden sheds we see a number of skilled labourers
+at work, busy with their chisels and mallets, cutting out, according
+to the patterns made from the architect's detailed drawings, the
+portions of tracery for windows, or the finials, crockets, and other
+features of the future building. In another part of the yard may be
+seen the stone-cutters, working in pairs and slowly pulling backwards
+and forwards those long saws which, with the help of water and sand,
+in time cut through the biggest blocks. All this work then may be
+summed up under the one word, "ornamentation," for it includes the
+cutting and carving of the stone.
+
+Our three lines of inquiry may now be summed up in these three words,
+which are easily remembered:--
+
+    _Transportation_,
+    _Elevation_,
+    _Ornamentation_.
+
+Taking the first of these subjects for consideration in the present
+chapter, we have now to inquire into the nature of the materials of
+which mountains are composed and the means by which they have been
+brought together and compacted into hard rock.
+
+First, with regard to the nature of the materials which Mother Earth
+uses to build her rocky ramparts: they are the same as the ordinary
+rocks of which the earth's crust is composed; and the greater part of
+them have been formed by the action of water. These are the ordinary
+"stratified" rocks, which in one form or another meet us almost
+everywhere, and may be said to be aqueous deposits, or sediments
+formed in seas and inland lakes. They are always arranged in layers,
+known to geologists as "strata," because they have been gently laid
+down, or strewn (Latin, _stratum_), at the bottom of some large body
+of water. There were pauses in the deposition of the materials,
+during which each layer had time to harden a little before the next
+one was formed. This accounts for the stratification. In this way
+great deposits of sandstone, clay, and limestone, with their numerous
+varieties, have been in the course of ages gradually piled up, till
+they have attained to enormous thickness, which at first sight seem
+almost incredible; but the bed of the seas in which they formed was
+probably undergoing a slow sinking process that kept pace with the
+growth of these deposits, otherwise the sea might have been more or
+less filled up.
+
+And these processes are still going on. In fact, it is entirely by
+watching what goes on now that geologists are able to explain what
+took place a very long time ago when there were no human beings on
+the earth to record the events that took place. And so we argue
+from the present to the past, from the known to the unknown. In
+other words, geology is based upon physical geography, which tells
+us of the changes now in progress on the earth. Thus, sandstone,
+as frequently met with in different parts of Great Britain, and
+largely used for building purposes, such as the familiar old red
+sandstone[20] of South Wales, Hereford, and the north of England and
+different parts of Scotland, was once soft sand in no way at all
+different from the sand of the seashore at the present day, or of the
+sandy bed of the North Sea. In process of time it became hardened,
+and acquired its characteristic red colour, which is due to oxide of
+iron. In some places numerous fossil fishes have been discovered in
+this interesting formation, so intimately associated with the name
+of Hugh Miller, who first thoroughly explored it; these and other
+remains entombed therein tell us of the strange forms of life which
+flourished on the earth during that very old-fashioned period of
+the world's history; and by putting together all kinds of evidences
+derived from the rock itself, geologists are able to form a very good
+idea of the way in which this rock-deposit was accumulated, always,
+however, basing their conclusions on a thorough knowledge of what
+goes on at the present day in seas, rivers, and inland lakes.
+
+  [20] The reader will find an account of the old red sandstone in
+  the writer's "Autobiography of the Earth" (Edward Stanford, 1890).
+
+In the great series of stratified rocks forming what is commonly
+called the crust of the earth (an unfortunate term which has survived
+from the time when the interior of the earth was generally believed
+to be in a fiery molten condition, and covered by a thin coating of
+solid rock at the surface), there are besides the sandstones, of
+which we have just spoken, great deposits of dark-coloured clays,
+shales, and slates. All these can be accounted for by the geologist.
+They are simply different states of what was once soft mud. The
+slates tell us that they have been subjected to very severe pressure,
+which squeezed their particles till they were elongated and all
+arranged in one direction, and this is the reason why they split up
+into thin sheets.
+
+Others, again, represent vast deposits of carbonate of lime,
+thousands of feet thick and now occupying hundreds of square miles
+of the earth's surface. Limestone rocks are as abundant in our own
+country as the sandstones, shales, or slates. The chalk of which
+the North and South Downs are composed is a familiar example. It is
+seen again forming Salisbury Plain, in Hampshire and the Isle of
+Wight, and then it may be traced running up the country in a long
+band through the counties of Oxford, Cambridge, Lincoln, until it
+reaches the coast at Flamborough Head in Yorkshire. Then we have the
+Bath Oölites so much used in building, for they form an admirable
+"freestone" that can be easily carved and cut in any direction (hence
+the term "freestone"); and lastly, the great mountain limestone so
+well developed in South Wales, Yorkshire, and the Lake country. All
+these were slowly built up at the bottom of the seas which existed
+in past ages; great beds of gravel formed at the mouths of rivers,
+and long banks of pebbles and rounded stones collected on the shore
+of primeval seas, and were ground against each other as now by
+the action of the waves, until all their corners were rubbed off.
+Pebble-beds, called by geologists conglomerates, are met with among
+the stratified rocks; and their story is easily read by studying
+what takes place at the present day on our seashores.
+
+  [Illustration: CHALK ROCKS, FLAMBOROUGH HEAD. FROM A PHOTOGRAPH
+  BY G. W. WILSON.]
+
+Now, the sandstones, clays, gravels, and pebble-beds all represent,
+as will presently be explained, so much material worn away from the
+surface of the land and swept into the ocean (or in some cases into
+inland seas and lakes) by streams and rivers, which are the great
+transporting agents of the world. Hence such deposits of débris,
+supplied by the constant wear and tear of all rocks exposed to the
+atmosphere, are truly sedimentary and have a purely mechanical
+origin. But it is not so with the limestones. The latter were never
+transported, but grew at the bottom of the sea in very wonderful
+ways. They have nothing to do with the wear and tear of the land to
+which the others owe their existence, but represent vast quantities
+of carbonate of lime extracted from sea water. Sea water contains
+a certain amount of this substance in a dissolved state, or "in
+solution," as a chemist would say; and the way in which this is
+extracted by the agency of various creatures, such as coral polypes
+and little microscopic creatures that build their shells of
+carbonate of lime, of great beauty, forms one of the most interesting
+subjects presented to the student of physical geography. Hence,
+since limestone can only be accounted for by the agency of living
+organisms,[21] it is rightly termed an _organic deposit_, and the
+others are said to be _mechanical deposits_. But both are called
+"aqueous rocks," because they are formed under water. It is important
+to distinguish clearly between these two very different methods of
+rock-formation.
+
+  [21] The flints usually found in limestone are also of organic
+  origin.
+
+But although water plays such a very important part in the making of
+the common rocks around us, yet there are others which have quite a
+different origin,--rocks which have come up from below the surface of
+the earth in a heated and molten condition, such as the lavas that
+flow from volcanoes in active eruptions and the showers of ashes
+and fine volcanic dust which often attend such eruptions (see chap.
+viii., pp. 271-272). Some highly heated rocks, though they never rise
+to the surface to form lava-flows, are forced up with overwhelming
+pressure from below, and wedge themselves into the sedimentary rocks
+that overlie them, thus forming what are known as volcanic dykes, and
+intrusive masses or sheets of once molten rock. In this category we
+include such rocks as basalt, felstone, pitchstone, and other rocks
+of fiery origin that have flowed from volcanoes as lava, as well as
+those like granite, which have cooled and become solid _below_ the
+surface, and are Plutonic, or deep-seated, igneous rocks. Granite
+may be exposed to the surface of the earth when the rocks which once
+overlaid it have been worn away or "denuded." It is frequently seen
+in the central regions of mountain-chains, where a vast amount of
+erosion has been effected. Thus we see that heat has played its part
+in the making of rocks; and for this reason such rocks as we have
+just mentioned are called _igneous_. Fire and water are therefore
+very important geological agents; but we should say heat rather than
+fire, because the latter word might convey a false impression. No
+rocks can be burned except coal, which may be considered rather as a
+mineral deposit than as a rock. Some rocks may be heated, and undergo
+many and various changes in their mineral composition; but they are
+not capable of combustion.
+
+So far, then, we have learned that the rocks exposed to view on
+the surface of the earth may be divided into two classes; that is,
+aqueous and igneous. There is yet a third class, which, though of
+aqueous origin, has in course of time suffered considerable from
+the internal heat of the earth and the enormous pressure due to the
+weight of overlying rocks. Such rocks have been greatly changed
+from their original condition, both in appearance and in mineral
+composition, and are said to be "metamorphic," a word which implies
+change. Thus chalk, or other limestone rock, has been metamorphosed
+into marble; shales and slates into various kinds of "schists,"[22]
+such as mica-schist, and even into gneiss, which closely resembles
+granite. And it is quite possible that even granite may in some cases
+be the result of the melting and consolidation under great pressure
+of certain familiar stratified rocks. It is quite conceivable that
+slate might be converted into granite, for their chemical composition
+is similar, only the minerals of which it is composed would require
+to be rearranged and grouped into new compounds. This would seem
+quite possible; but at present we have no direct proof of such a
+change having taken place. Even igneous rocks are found in some
+places to have suffered very considerable change.
+
+  [22] Schists are so named from their property of splitting into
+  thin layers. Their structure is crystalline; and the layers, or
+  folia, consist usually of two or more minerals, but sometimes
+  of only one. Thus mica-schist consists of quartz and mica, each
+  arranged in many folia, but it splits along the layers of mica.
+
+In some inland seas, like the Caspian Sea, deposits of rock salt and
+gypsum may be formed by chemical precipitation, owing to evaporation
+from the surface.
+
+The various kinds of rock known to geologists may be conveniently
+arranged as follows:
+
+                    {                 { Clay, shale, slate, etc.
+                    { I. Sedimentary. { Sandstones.
+                    {                 { Conglomerates.
+                    {
+    Rocks of        {                 { Limestones.
+    aqueous         { II. Organic.    { Flint.
+    origin.         {                 { Coal.
+                    {
+                    { III. Chemical.  { Rock salt.
+                    {                 { Gypsum, etc.
+
+                    { I. Volcanic.    { Lavas.
+    Rocks of        {                 { Volcanic ashes, etc.
+    igneous origin. {
+                    { II. Plutonic.   { Basalt.
+                    {                 { Granite.
+
+    Metamorphic rocks                 { Marbles.
+    of aqueous and                    { Various kinds of schists.
+    igneous origin.                   { Gneiss, etc.
+
+So far we have only attempted to state very briefly the different
+kinds of rocks, and to point out that they were formed in various
+ways. We must now consider the question of rock-making more closely,
+and see what we can learn about the wonderful ways in which rocks are
+made; and it may be instructive to glance at the conflicting opinions
+on this subject which learned men held not very long ago.
+
+At the end of the last century a great controversy took place on
+the question of the origin of rocks, and the learned men of the day
+were divided into two parties. One of these parties, following the
+teaching of Werner, professor of mining at Freyburg, who inspired
+great enthusiasm among his disciples, declared that all rocks were
+formed by the agency of water. This was a very sweeping and of course
+rash conclusion. But whenever they examined rocks, they found so many
+clear evidences of the action of water that a powerful impression
+of the importance of this agency was naturally made on their minds.
+They found rocks uniformly arranged in great layers which extended
+for long distances, and containing the remains of animals which must
+undoubtedly have lived in the seas or estuaries. These layers were
+further divided into smaller layers, such as clearly were formed
+by the slow settling down of sand and mud. Others again contained
+gravels and rounded pebbles, testifying in no uncertain way to
+the action of water. Even the little grains of sand are obviously
+water-worn. This teaching was quite sound so long as they confined
+their attention to clays, sandstones, and limestones; but when they
+came to basalt and granite, a blind adherence to the views of their
+master caused them to shut their eyes to the clear evidences of the
+action of heat, presented by such rocks. The crystalline structure
+of such rocks; their irregular arrangement, often so different
+from the uniform disposition of the stratified rocks (although it
+must be admitted that ancient lava-flows often lie very evenly
+between aqueous rocks), and the way in which they burst through
+overlying rocks, thus proving their former molten condition; the
+signs of alteration exhibited in the aqueous rocks into which they
+intruded themselves (changes which are obviously due to the action
+of heat),--these and other evidences were entirely overlooked, and
+Werner declared that basalt had been found as a sediment under water.
+
+This school of geologists, believing so strongly in the all-powerful
+influence of Father Neptune, received the not inappropriate title of
+"Neptunists."
+
+On the other hand, the party who happened to be in districts where
+granite, basalt, and such igneous rocks abounded were equally
+impressed with the importance of the powerful agency of heat. To
+them nearly every rock they met with seemed to show some signs of
+its action. And since Pluto was the classical deity of the lower
+regions, and the earth shows evidences in places of greater heat
+below the surface, this party received the title of "Plutonists;"
+and so the battle raged hotly for some time between the Neptunists,
+with their claims for cold water, and the fiery Plutonists of the
+rival school of Edinburgh, with their subterranean heat. Fire and
+water are never likely to agree; and they did not do so in this case.
+But now that the battle is over, and both sides are found to have
+been partly right and partly wrong,--though the Neptunists have the
+advantage,--we can afford to smile at the fierceness of the contest,
+and wonder how it was that each side thought they were so entirely in
+the right.
+
+Let us now consider the aqueous rocks, and see if we can gain a clear
+idea of the ways in which they were formed; and first, we will take
+those of a purely sedimentary origin,--the sandstones, pebble-beds,
+gravels, and clays. These, as the reader has already probably
+guessed, have all been transported by means of streams and rivers,
+and settled down quietly in seas at the mouths of rivers or in inland
+lakes. There is no trace of the action of heat in the forming of
+these rocks, though they often show signs of having suffered more or
+less change from contact with highly heated igneous rocks of later
+date which forcibly intruded themselves from below; and if the change
+thus effected were considerable, we should call the rocks so altered
+metamorphic. But we are now dealing with their original state and how
+they were made; and of that there is no possible doubt whatever. So
+for the time being we may call ourselves Neptunists.
+
+Streams and rivers are the great transporting agents whereby the
+never-failing supply of débris from the waste of the land is
+unceasingly brought down from the mountains and hills, through the
+broad valleys and along the great plains, until finally it is flung
+into the sea. The sea is the workshop where all the sedimentary
+rocks are slowly manufactured from the raw material brought to it
+by the rivers. But for the present we must confine our attention to
+the question of transport. Referring back to our illustration of the
+cathedral, we may say that streams and rivers play the part of cart
+and horses. They bring the materials down from the quarry to the
+scene of action,--the workshop where they are wanted. The quarries,
+in this case, may be said to be almost everywhere. For wherever rocks
+and soil are exposed to the action of wind and weather, there is
+certain to be more or less decay and crumbling away. But it is among
+the hills and in the higher parts of the mountains that the forces
+of destruction are most active. How this is brought about will be
+discussed in the seventh chapter, on the carving of the hills. The
+frequent slopes covered with loose stones are sufficient evidence of
+the continual destruction that takes place in these regions.
+
+The transporting powers of rivers are truly prodigious. Looking at
+a stream or river after heavy rain, we see its waters heavily laden
+with mud and sand; but it is difficult to realise from a casual
+glance the vast amount of material that is thus brought down to lower
+levels. If we could trace the sediment to its source, we must seek it
+among the rocks of mountains far away. Step by step we may trace it
+up along the higher courses of the river, then along mountain streams
+rushing over their rocky beds, tumbling in cascades over broken
+rocks, or leaping in waterfalls over higher projections of rock,
+until we come to the deep furrows on the sides of mountains along
+which loose fragments of rock come tumbling down with the cascades of
+water that run along these steep channels after heavy rain, leaving
+at the base of the mountain great fan-shaped heaps of stones.
+
+    "Oft both slope and hill are torn
+    Where wintry torrents down have borne,
+    And heaped upon the cumbered land
+    Its wreck of gravel, rocks, and sand."
+
+These accumulations are gradually carried away by the larger mountain
+streams, which in hurrying them along cause a vast amount of wear
+and tear; so that their corners are worn off, and they get further
+and further reduced in size, becoming mere round pebbles lining
+the bed of the stream, and finally by the time they reach the large
+slow-moving rivers of the plains are mainly reduced to tiny specks
+of mud or grains of sand. So then the rivers and streams not only
+transport sediment, but they manufacture it as they go along. And
+thus they may be considered as great grinding-mills, where large
+pieces of stone go in at one end, and only fine sand and mud come out
+at the other.
+
+The amount of land débris thus transported depends partly on the
+carrying power of rivers, which varies with the seasons and the
+annual rainfall; partly on the size of the area drained by a river;
+and again, partly on the nature of the rocks of which that area is
+composed.
+
+A stream, moving along at the rate of about half a mile (880 yards)
+an hour, which is a slow, rate, can carry along ordinary sandy soil
+suspended in a cloud-like fashion in the water; when moving at the
+rate of two thirds of a mile (about 1,173 yards) an hour, it can roll
+fine gravel along its bed; but when the rate increases to a yard
+in a second, or a little more than two miles an hour, it can sweep
+along angular stones as large as an egg. But streams often flow much
+faster than this, and so do rivers when swollen by heavy rain.
+
+A rapid torrent often flows at the rate of eighteen or twenty miles
+an hour, and then we may hear the stones rattling against each other
+as they are irresistibly rolled onward; and during very heavy floods,
+huge masses of rock as large as a house have been known to be moved.
+
+These are the two principal ways in which streams and rivers act as
+transporting agents: they carry the finer materials in a suspended
+state (though partly drifting it along their beds); and they push
+the coarser materials, such as gravel, bodily along. But there
+is one other way in which they carry on the important work of
+transportation, which, being unseen, might easily escape our notice.
+Every spring is busily employed in bringing up to the surface mineral
+substances which the water has dissolved out of the underground
+rocks. This invisible material finds its way, as the springs do, to
+the rivers, and so finally is brought into that great reservoir, the
+sea. Rain and river water also dissolve a certain amount of mineral
+matter from rocks lying on the surface of the earth. Now, the
+material which is most easily dissolved is carbonate of lime. Hence
+if you take a small quantity of spring or river water and boil it
+until the whole is evaporated, you will find that it leaves behind
+a certain amount of deposit. This, when analysed by the chemist,
+proves to be chiefly carbonate of lime; but it also contains minute
+quantities of other minerals, such as common salt, potash, soda,
+oxide of iron, and silica, or flint. All these and other minerals are
+found to be present in sea water.
+
+The waters of some of the great rivers of the world have been
+carefully examined at different times, in order to form some idea of
+the amount of solid matter which they contain, both dissolved and
+suspended; and the results are extremely important and interesting,
+for they enable us to form definite conclusions with regard to their
+capacity for transport. This subject has been investigated with great
+skill by eminent men of science. The problem is a very complicated
+one; but it is easy to see that if we know roughly the number of
+gallons of water annually discharged into the sea by a big river,
+and the average amount of solid matter contained in such a gallon
+of water, we have the means of calculating, by a simple process
+of multiplication, the amount of solid matter annually brought
+down to the sea by that river. But we must also add the amount of
+sand, gravel, and stones pushed along its bed. This may be roughly
+estimated and allowed for. These are some of the results:
+
+The amount of solid matter discharged every year by that great river,
+the Mississippi, if piled up on a single square mile of the bed of
+the sea,--say, in the Gulf of Mexico, where that river discharges
+itself,--would make a great square-shaped pile 268 feet high. But the
+Gulf Stream, sweeping through this gulf, carries the materials for
+many and many a mile away; so that in course of time it gradually
+sinks and spreads itself as a fine film or layer over part of the
+great Atlantic Ocean. The mud brought down by the great river
+Amazon spreads so far into the Atlantic Ocean as to discolour the
+water even at a distance of three hundred miles. The Ganges and the
+Brahmapootra, flowing into the Bay of Bengal, discharge every year
+into that part of the Indian Ocean 6,368,000,000 cubic feet of solid
+matter. This material would in one year raise a space of fifteen
+square miles one foot in height. The weight of mud, etc., that these
+rivers bring down is sixty times that of the Great Pyramid of Egypt,
+or about six million tons.
+
+Or, to put the matter in another way, if a fleet of more than eighty
+"Indiamen," each with a cargo of fourteen hundred tons of solid
+matter, sailed down every hour, night and day, for four months, and
+discharged their burdens into the waters of the Indian Ocean, they
+would only do what the mighty Ganges does quietly and easily in the
+four months of the flood season.
+
+It is probable that even the Thames, a small river compared to
+those just mentioned, manages to bring down, in one way or another,
+fourteen million cubic feet of solid matter. These few figures may
+suffice to give the reader some idea of the enormous amount of
+rock-forming materials brought down to the seas at the present day.
+
+Of course they are spread out far and wide by the numerous ocean
+currents, some of which flow for hundreds of miles; and so the bed of
+the sea can only be very slowly raised by their accumulation. Still
+the geologist can allow plenty of time, for there is no doubt that
+the world is immensely old; and if we allow thousands of years, we
+may easily comprehend that deposits of very considerable thickness
+may in this way accumulate on the floors of the oceans. Also the
+coasts of continents and islands suffer continual wear and tear at
+the hands of sea waves; and thus the supply of sediment is increased.
+
+When the geologist comes to study the great rock-masses--hundreds,
+and even thousands, of feet in thickness--of which mountain-ranges
+are composed, he finds all those kinds of rock which we have
+just been considering,--sandstones, shales (or hardened clays),
+pebble-beds, and limestones,--and endeavours to picture to himself
+their gradual growth in the ways we have described. In so doing, he
+is driven to the conclusion that many thousands of years must have
+been occupied in their construction.
+
+We must now say a few words about those other aqueous rocks which
+have an organic origin, of which limestone is the chief. It is indeed
+a startling conclusion that deposits of great thickness, and ranging
+for very many miles over the earth's surface, have been slowly built
+up through the agency of marine animals extracting carbonate of lime
+from the sea. Yet such is undoubtedly the case. Of this important
+process of rock-building coral reefs are the most familiar example.
+The great barrier reef along the northeast coast of Australia is
+about 1,250 miles long, from ten to ninety miles in width, and rises
+at its seaward edge from depths which in some places certainly exceed
+eighteen hundred feet. It may be likened to a great submarine wall.
+Now, all this solid masonry is the work of humble coral polypes (not
+"insects"), building up their own internal framework or skeleton
+by extracting carbonate of lime from sea water. Then the breakers
+dashing against coral reefs produce, by their grinding action, a
+great deal of fine "coral-sand" and calcareous mud, which covers the
+surrounding bed of the sea for many miles.
+
+Now, geologists find that some limestone formations met with in the
+stratified rocks have certainly been formed in this way; for example,
+certain parts of the great "mountain limestone." This is proved by
+the fossil corals it contains, and by tracing the old coral reefs;
+but it is also largely formed by the remains of other graceful
+calcareous creatures known as encrinites, or "sea-lilies," with long
+branching arms that waved in the clear water. Such creatures still
+exist in some deeper parts of the sea, and look more like plants
+than animals. In former ages they existed in great abundance, and so
+played an important part as rock-formers,--for their stems, branches,
+and all are made of little plates of carbonate of lime, beautifully
+fitting together like the separate bones, or vertebræ, composing
+the backbone of a fish; and when the creatures died, these little
+plates no longer held together, but were scattered on the floor
+of the sea-bed. Shell-fish abounded too, and their shelly remains
+accumulated into regular shell-beds in some places. But at times mud
+and sand would come and cover over all these organic deposits.
+
+But of all rocks that have an organic origin, chalk is the most
+interesting. Geologists were for a long time puzzled to know how this
+rock could have been formed; but some soundings made in the Atlantic
+Ocean previous to the laying of the first Atlantic cable led to a
+very important discovery, which at once threw a flood of light on
+the question. Samples of the mud lying on the bed of this ocean at
+considerable distances from the European and American coasts, and
+at depths varying from one thousand to three thousand fathoms, were
+brought up by sounding apparatus.
+
+Little was it thought that the dull grey ooze covering a large part
+of the Atlantic bed would bring a message from the depths of the sea,
+and furnish the answer to a great geological problem. Yet such was
+the case; for under the microscope this mud was seen to be chiefly
+composed of very minute and very beautiful shells, now known as
+_foraminifera_, and much prized by microscopists. These tiny shells
+are found at or near the surface of the sea; and after the death of
+the creatures that inhabit them (which are only lumps of protoplasm
+with no organs of any kind), the shells slowly sink down to the bed
+of the ocean. Now, these creatures multiply at so inconceivable a
+rate that a continuous shower of dead shells seems to be taking
+place, and the result is the slow accumulation over vast areas of the
+Atlantic and Pacific oceans of a great deposit of calcareous ooze,
+which if raised above the sea-level would harden into a rock very
+similar to chalk.
+
+  [Illustration: MICROPHOTOGRAPHS ILLUSTRATING ROCK FORMATION.
+
+  I. Foraminifera. II. Section of Granite. III. Nummulitic
+  Limestone.]
+
+But this process only takes place in the deeper parts of our seas,
+far removed from land, where the supply of land-derived materials
+fails,--for even the finest mud supplied by rivers probably all
+settles down before travelling two or three hundred miles from its
+native shores.
+
+Thus we learn that when one agency fails, Nature makes use of another
+to take up the important work of rock-building. How the other rocks
+which we mentioned in our list were formed,--such as granite, basalt,
+and the metamorphic rocks,--we must explain in a future chapter
+dealing with volcanoes and their work.
+
+
+
+
+CHAPTER VI.
+
+HOW THE MOUNTAINS WERE UPHEAVED.
+
+   The notion that the ground is naturally steadfast is an
+   error,--an error which arises from the incapacity of our senses
+   to appreciate any but the most palpable, and at the same time
+   most exceptional, of its movements. The idea of _terra firma_
+   belongs with the ancient belief that the earth was the centre
+   of the universe. It is, indeed, by their mobility that the
+   continents survive the increasing assaults of the ocean waves,
+   and the continuous down-wearing which the rivers and glaciers
+   bring about.--PROFESSOR SHALER.
+
+
+We have found out the quarries which supplied the rocky framework of
+mountains, and have learned how the work of transporting these vast
+quantities of stone was accomplished by the agency of ever-flowing
+glaciers, rivers, and streams.
+
+We must now consider the second stage of the work, and inquire how
+the mountains were raised up. Referring back to our illustration
+of the cathedral (see pages 143-147), it will be remembered that
+this work was included under the head of _Elevation_. But perhaps
+some one might ask: "How do you know that the mountains have been
+elevated or upheaved? Is it not enough to suppose that they owe their
+height entirely to the fact that they are composed of harder rock,
+and so have been more successful in resisting the universal decay and
+destruction?" Now, such an objection contains a good deal of truth,
+for mountains _are_ formed of hard rocks; but at the same time we
+know that the agents of denudation are more active among them than on
+the plains below, so that, in the higher mountain regions at least,
+the work of demolition may actually proceed faster than it does on
+low ground.
+
+Mountains are higher than the rest of the world, not merely because
+they are built of more lasting material, but also because they have
+been uplifted for thousands of feet above the level of the sea; and
+the evidence of their upheaval is so plain as to be entirely beyond
+doubt.
+
+Let us inquire into the nature of this evidence. We have seen that
+the rocks of which mountains are composed were for the most part
+formed at the bottom of the sea. When the geologist finds, as he
+frequently does, buried in mountain rocks the fossil remains of
+creatures that must have lived in the sea (and often very similar to
+those living there now), he is compelled to think of the gigantic
+upheavals that must have taken place before those remains could
+arrive at their present elevated position.
+
+Numerous examples might be given; but we will only mention three. In
+the Alps marine fossils have been detected at a height of 10,000 feet
+above sea-level, in the Himalayas at a height of 16,500 feet, and in
+the Rocky Mountains at a height of 11,000 feet.
+
+Again we must take it for granted that all the stratified or
+sedimentary rocks (see pages 148-149) with some trivial exceptions,
+such as beds of shingle and conglomerates, have been formed in
+horizontal layers. This is one of the simple axioms of geology to
+which every one must assent.
+
+Now, if we find in various parts of the continents, and especially
+among the mountains, such strata sloping or "dipping" in
+various directions, sometimes only slightly, but sometimes very
+steeply,--nay, even standing up on end,--the conclusion that they
+have been upheaved and pushed or squeezed into these various
+positions by some subsequent process is irresistible. But this is
+not all; for in every mountain region we find that the rocks have
+been crumpled, twisted, and folded in a most marvellous manner. Solid
+sheets of limestone may be seen, as it were, to writhe from the
+base to the summit of a mountain; yet they present everywhere their
+truncated ends to the air, and from their incompleteness it is easy
+to see what a vast amount of material has been worn away, leaving,
+as it were, mere fragments behind. The whole geological aspect of
+the Alps (for example) is suggestive of intense commotion; and they
+remain a marvellous monument of stupendous earth-throes, followed by
+prolonged and gigantic denudation (see diagrams, chap. ix., p. 307).
+
+There are certain features found in all mountain-chains which must
+be carefully borne in mind, especially when we are considering the
+explanations that have been suggested with regard to their upheaval.
+These may be briefly stated as follows:--
+
+   1. Mountain-chains tend to run in straight or gently curving
+   lines.
+
+   2. Their breadth is small compared to their length, and their
+   height smaller still.
+
+   3. They rise sharply and are clearly marked off from the
+   country on either side.
+
+   4. They form the backbones of continents.
+
+   5. The rocks of which they are composed have been greatly
+   disturbed, folded, and contorted.
+
+   6. There is often a band of crystalline rocks (granite, gneiss,
+   etc.) running along the centre of a high range.
+
+   7. They are connected with lines of volcanoes.
+
+   8. They are frequently affected by earthquakes.
+
+Having arrived at the conclusion that the mountains show evident
+signs of upheaval, let us proceed to inquire whether any movements,
+either upward or downward, are taking place now on the earth, or can
+be proved to have done so within comparatively recent times. On this
+question there is ample evidence at our disposal.
+
+More than one hundred and thirty years ago, Celsius, the Swedish
+astronomer, was aware, from the unanimous testimony of the
+inhabitants of the sea-coasts, that the Gulf of Bothnia was
+constantly diminishing both in depth and extent. He resorted to
+measurements in order to prove (as he thought) that the waters of
+the Baltic were changing their level. This was a mistaken idea; and
+we now understand that the level of the sea does not change, except
+under the influence of the daily rise and fall of the tide, which is
+easily allowed for. However, that was the idea then; and it survived
+for some time. But if the sea-level were continually sinking, the
+water, which, owing to the influence of gravitation, must always
+remain horizontal, would equally retreat all round the Scandinavian
+peninsula and on all our seashores. But this is not the case. Again,
+it would be impossible on this theory to explain the curious fact
+that in some parts of the world the sea is gaining on the land, while
+in other places it is as surely retreating; for we cannot believe
+that in one part the sea-level is rising, while in another (not far
+off in some cases) it is sinking. No body of water could behave in
+this irregular fashion; and the sea could not possibly be rising and
+falling at the same time.
+
+Hence we may take it for granted that any change that we may notice
+in the relative level of land and sea _must_ be due to upward or
+downward movements in the land.
+
+But to return to Celsius. Old men pointed out to him various points
+on the coast, over which during their childhood the sea was wont to
+flow, and besides, showed him the water-lines which the waves had
+once traced out farther inland. And besides this, the names of places
+which implied a position on the shore, former harbours or ports now
+abandoned and situated inland, the remains of boats found far from
+the sea, and lastly, the written records and popular songs, left no
+doubt that the sea had retreated; and it seemed both to themselves
+and to the astronomer that the waters were sinking. In the year 1730
+Celsius, after comparing all the evidence he had collected, announced
+that the Baltic had sunk three feet, four inches, every hundred
+years. In the course of the following year, in company with Linnæus,
+the naturalist, he made a mark at the base of a rock in the island
+of Leoffgrund, not far from Jelfe, and thirteen years afterwards was
+able to prove, as he thought, that the waters were still subsiding
+at the same rate, or a little faster. In reality, he had proved, not
+that the sea was sinking, but that the land was rising.
+
+Similar observations show that nearly the whole of Scandinavia is
+slowly rising out of the sea. At the northern end of the Gulf of
+Bothnia the land is emerging at the rate of five feet, three inches,
+in a century; but by the side of the Aland Isles it only rises three
+and one quarter feet in the same time. South of this archipelago it
+rises still more slowly; and farther down, the line of shore does not
+alter as compared with the level of the sea.
+
+But it is a curious fact that the extreme southern end of this
+peninsula is subsiding, as proved by the forests that have been
+submerged. Several streets of some towns there have already
+disappeared, and the coast has lost on the average a belt of land
+thirty-two yards in breadth.
+
+The upward movement of the Scandinavian peninsula must have been
+going on for a long time, if we assume that it was always at the same
+rate as at present; for we find beds of seashells of living species
+at heights of six or seven hundred feet above the level of the sea.
+Great dead branches of a certain pink coral, found in the sea at a
+depth of over one hundred and fifty to three hundred fathoms, are
+now seen in water only ten or fifteen fathoms deep. It must have
+been killed as it was brought up into the upper and warmer layers of
+water. This is striking testimony.
+
+The pine woods too, which clothe the hills, are continually being
+upheaved towards the lower limit of snow, and are gradually withering
+away in the cooler atmosphere; and wide belts of forest are composed
+of nothing but dead trees, although some of them have stood for
+centuries.
+
+Geologists have proved that the Baltic Sea formerly communicated
+by a wide channel with the North Sea, the deepest depressions of
+which are now occupied by lakes in the southern part of Sweden; for
+considerable heaps of oyster-shells are now found in several places
+on the heights commanding these great lakes. Then we have in Denmark
+the celebrated "kitchen-middens," heaps of rubbish also largely
+composed of oyster-shells which the inhabitants, in the "Stone
+Age," collected from the bottoms of the neighbouring bays. At the
+present day the waters of the Baltic, into which rivers bring large
+quantities of fresh water, do not contain enough salt for oysters to
+grow there; but the oyster-shells prove that the Baltic Sea and these
+inland lakes were once as salt as the North Sea is now. This can only
+be explained by supposing that the Baltic was not so shut in then as
+it is in these days. The bed of the old wide channel has risen, and
+what once was sea is now land.
+
+Again, it is very probable that the great lakes and innumerable
+sheets of water which fill all the granite basins of Finland have
+taken the place of an arm of the sea which once united the waters of
+the Baltic to those of the great Polar Ocean. And so there must have
+been upheaval here as well.
+
+The old sea-beaches, now above the level of the highest tides, that
+are found in many parts of the Scandinavian, Scottish, and other
+coasts, furnish plain evidence of upheaval.
+
+At the present day, between the lines of high tide and low tide, the
+sea is constantly engaged in producing sand and shingle, spreading
+them out upon the beach, mingling them with the remains of shells
+and other marine animals, and sometimes piling them up, sometimes
+sweeping them away. In this way a beach often resembles a terrace.
+When the land is upheaved rapidly enough to carry up this line
+of beach-deposits before they are washed away by the waves, they
+form a flat terrace, or what is known as a "raised beach." The old
+high-water mark is then inland; its sea-worn caves become in time
+coated with ferns and mosses; the old beach forms an admirable
+platform on which meadows, fields, villages, and towns spring up; and
+the sea goes on forming a new beach below and beyond the margin of
+the old one.
+
+The Scottish coast-line, on both sides, is fringed with raised
+beaches, sometimes four or five occurring above each other, at
+heights of from twenty-five to seventy-five feet above the present
+high-water mark. Each of these lines of terrace marks a former lower
+level at which the land stood with regard to the sea; and the spaces
+between them represent the amount of each successive rise of the
+land. Each terrace was formed during a pause, or interval, in the
+upward movement, during which the waves had time to make a terrace,
+whereas, while the land kept on rising, they had no time to do so.
+Thus we learn that the upheaval of the country was interrupted by
+considerable pauses.
+
+Sometimes old ports and harbours furnish evidence of upheaval. Thus,
+the former Roman port of Alaterva (Cramond) in Scotland, the quays of
+which are still visible, is now situated at some distance from the
+sea, and the ground on which it stands has risen at least twenty-four
+feet. In other places the scattered débris shows that the coast has
+risen twenty-six feet. And by a remarkable coincidence, the ancient
+wall of Antoninus, which in the time of the Romans stretched from sea
+to sea, and served as a barrier against the Picts, comes to an end at
+a point twenty-six feet above the level of high tides. In the estuary
+of the Clyde there are deposits of mud, containing rude canoes and
+other relics of human workmanship, several feet above the present
+high-water mark.
+
+Raised beaches are found on many parts of the coast of Great Britain.
+Excellent examples occur on the coasts of Devon and Cornwall. On the
+sides of the mountainous fiords of Norway similar terraces are found
+up to more than six hundred feet above the sea; and as some of these
+rise to a greater height at a distance of fifty miles inland, it
+seems that there was a greater upward movement towards the interior
+of Norway than on the coasts.
+
+There is a celebrated raised beach on the side of a mountain in
+North Wales, known as Moel Tryfaen, where the writer gathered a
+number of marine shells at a height of 1,357 feet.
+
+But Scandinavia and Great Britain are not the only parts of Europe
+where an upward movement has taken place, for the islands of Nova
+Zembla and Spitzbergen show evidence of the same kind; and the coast
+of Siberia, for six hundred miles to the east of the river Lena, has
+also been upraised. On the banks of the Dwina and the Vega, 250 miles
+to the south of the White Sea, Murchison found beds of sand and mud
+with shells similar to those which inhabit the neighbouring seas, so
+well preserved that they had not lost their colours.
+
+Again, the ground of the Siberian _toundras_ is to a large extent
+covered with a thin coating of sand and fine clay, exactly similar
+to that which is now deposited on the shores of the Frozen Ocean.
+In this clay, the remains of the mammoth, or woolly elephant, now
+extinct, are preserved in great numbers.
+
+Parts of Northern Greenland have also risen; while at the southern
+end of this frozen land a downward movement is still taking place.
+
+The best-known example of these slow movements within historic times
+is the so-called Temple of Serapis in the Bay of Baie, near Naples.
+The ruins of this building, which was probably a Roman bath, consist
+of a square floor paved with marble, showing that it possessed a
+magnificent central court. This court, when perfect, was covered with
+a roof supported by forty-six fine columns, some of marble, others
+of granite. There is still a hot spring behind, from which water was
+conducted through a marble channel. All the columns but three were
+nearly buried in the soil which covered the whole court, when the
+ruins were first discovered. Now, each of the three marble columns
+that are still standing shows clear evidence of having been depressed
+below the sea-level, for they all exhibit a circular row of little
+holes bored by a certain marine shell-fish, known as _Lithodomus
+dactylus_, at a height of twelve feet from the floor; each row is
+about eight feet broad. The shells may still be seen inside the
+little pear-shaped holes which the shell-fish bored for themselves;
+and the same shell-fish still live in the waters of the Mediterranean
+and bore holes in the limestone rocks.
+
+It is therefore quite clear that these columns must have been under
+water to a depth of twenty feet or so, and also that they must have
+remained under water for some considerable time, during which the
+shell-fish made these borings. Then an upheaval took place whereby
+the whole building was elevated to its present level. But underneath
+the present floor, at a depth of five feet, were discovered the
+remains of an older floor. This probably belonged to an earlier
+building which had in like manner been depressed below sea-level. We
+thus learn that the land in this spot had been sinking for a long
+time, and that at some subsequent time it rose. The fallen columns
+suggest the idea that they were thrown down by earthquakes. At the
+present time the land here is again sinking at the rate of one inch
+in three or four years.
+
+But the first example of upheaval within comparatively recent times,
+and one which is instructive as throwing some light on the subject of
+the present chapter,--namely, the upheaval of mountain-chains,--is to
+be found along the western mountainous coast of South America. Here
+we have the magnificent ranges of the Andes running along the whole
+length of this continent. The illustrious Charles Darwin, during
+his famous trip in the "Beagle," discovered numerous raised beaches
+along this coast, and at once perceived their importance to the
+geologist. The terraces are not quite horizontal, but rise towards
+the south. On the frontier of Bolivia, they are seen at heights of
+from sixty-five to eighty feet above sea-level; but nearer the higher
+mass of the Chilian Andes they are found at one thousand feet, and
+near Valparaiso, in Chili, at thirteen hundred feet above the sea.
+Darwin also discovered that some of the upheavals thus indicated took
+place during the human period; for he found in one of the terraces
+opposite Callao, in Peru, at a height of eighty feet, shells with
+bones of birds, ears of wheat, plaited reeds, and cotton thread,
+showing that men had lived on the terrace. These relics of human
+industry are exactly similar to those that are found in the _huacas_,
+or burial-places, of the ancient Peruvians. There can be no doubt
+that the island of San Lorenzo, and probably the whole of the coast
+in its neighbourhood, have risen eighty feet or more since the Red
+Man inhabited the country.
+
+Callao probably forms the northern limit of the long strip of coast
+that has been upheaved, and the island of Chiloe the southern limit;
+but even thus the region of elevation has a length from north to
+south of about 2,480 miles.
+
+We noticed in the case of Scandinavia that the upward movement is
+greater in the interior of the mountain-range than at or near the
+coast; and it is interesting to find that the same difference has
+been observed in the case of the Andes. The upheaving force, whatever
+its nature, acts with more energy under the Chilian Andes than under
+the rocks of the adjacent coast.
+
+In New Zealand we have also evidences of upheaval; and if we trace
+out on the map a long line from the Friendly Isles and Fiji, through
+the Eastern Archipelago, and then on through the Philippine Islands,
+and finally to Japan and the Kurile Islands, we shall find scattered
+regions of elevation all along this great line, which is probably a
+mountain-chain, partly submerged, and along which numerous active
+volcanoes are situated.
+
+Putting together all the evidence that has been gathered on this
+subject, of which only a very small part is here given, we are
+warranted in concluding that taking the world generally, regions
+where active volcanoes exist are generally regions where upheaval is
+taking place. There is also a very interesting connection between
+mountain-chains and lines of volcanic action. From this it seems to
+follow, if lines of volcanic action are also lines of upheaval, that
+mountain-chains are undergoing upheaval at the present time. This
+is a conclusion in favour of which a good deal may be said. It is
+certainly true in the cases of the Scandinavian range, and also of a
+very large part of the Andes, to which we have already referred. The
+Highlands of Scotland and Scandinavia form the northern end of an old
+line of volcanic action running down the Atlantic Ocean through the
+Azores, Madeira, Cape Verde Islands, Ascension, St. Helena, right
+down to Tristan d'Acunha.
+
+In many other parts of the world we have evidences from submerged
+forests, the positions of certain landmarks with regard to the sea,
+and in some cases submerged towns, that movements of a downward
+nature are taking place.
+
+It is important to distinguish from these evidences the changes that
+take place where the waves of the sea are rapidly washing away the
+coast-line. Putting aside these cases, however, it has been clearly
+proved that in many regions a slow sinking of the land is going on.
+
+The eastern side of South America has not been so thoroughly observed
+as its western side; but there is still good reason to believe that
+a large part of this coast is sinking. So it appears that a see-saw
+movement is affecting South America, and that while one side is going
+up, the other is going down; and it is interesting to observe other
+examples of the same thing,--such as are afforded by Greenland and
+Norway.
+
+  [Illustration: THE SKAEGGDALFORS, NORWAY.
+
+  FROM A PHOTOGRAPH BY J. VALENTINE.]
+
+Again, while part of Labrador is rising, parts of the eastern coast
+of North America, as far down as Florida, are slowly sinking. Thus
+along the New England coast between New York and Maine, and again
+along the Gulf of St. Lawrence, we find numerous submerged forests
+with quantities of trees standing upright with their roots in old
+forest-beds, but with the tops of their stumps some feet below the
+level of high tide. In the case of New Jersey the subsidence is
+probably taking place at the rate of two feet in a hundred years.
+
+Before passing on to consider upward movements of a more rapid
+nature, such as are frequently caused by earthquakes, we may pause
+for a few moments to consider certain very slight, but nevertheless
+very interesting little movements, such as _slight pulsations_ and
+tremors, which have been observed to take place in the earth's crust
+(as it is called), and which of late years have been carefully
+studied.
+
+Professor Milne, a great authority on earthquakes, has noticed slight
+swayings of the earth, which though occupying a short time--from a
+few seconds to a few hours--are still too slow to produce a shock of
+any kind. These he calls "earth pulsations." They have been observed
+by means of delicate spirit-levels, the bubbles of which move with
+very slight changes of level at either end of the instrument. At
+present only a few experiments of this kind have been made; but they
+tell us that the surface of the earth (which is apparently so firm
+and immovable) is subject to slight but frequent oscillations. Some
+think that they depend upon changes in the weight of the atmosphere.
+If this is so, the balance between the forces at work below the
+earth's surface and those that operate on its surface must be
+very easily disturbed. Still we cannot see that this is a serious
+objection; on the contrary, there is much reason to think that any
+slight extra weight on the surface, such as might be caused by an
+increase of the pressure of the atmosphere, and still more by the
+accumulation of vast sedimentary deposits on the floor of the ocean,
+may be quite sufficient to cause a movement to take place. Moreover,
+Mr. G. H. Darwin has shown that the earth's crust daily heaves up and
+down under the attraction of the moon in the same kind of way that
+the ocean does; so that we must give up all idea of the solid earth
+being fixed and immovable, and must look upon it as a flexible body,
+like a ball of india-rubber (see chap. ix., pp. 314-315).
+
+Slight movements of rather a different kind have been noticed, to
+which the name of "earth-tremors" has been given. These are very
+slight jarrings or quiverings of the earth, too slight to be observed
+by our unaided senses, but rendered visible by means of very delicate
+pendulums and other contrivances. Now wherever such observations
+have been made it has been discovered that the earth is constantly
+quivering as if it were a lump of jelly. In Italy, where this subject
+has been very carefully studied, the tremors that are continually
+going on are found to vary considerably in strength; for instance,
+when the weather is very disturbed and unsettled, the movements of
+the pendulum are often much greater. Again, before an earthquake the
+instrument shows that the tremors are more frequent and violent.
+
+Another way of observing these curious little movements is by burying
+microphones in the ground. The microphone is a little instrument
+invented of late years which is capable of enormously magnifying the
+very slightest sounds, such as our ears will not detect. By its means
+one can hear, as some one said, "the tramp of a fly's foot," if he
+will be so obliging as to walk over it. It has thus been proved in
+Italy that the earth sends forth a confused medley of sounds caused
+by little crackings and snappings in the rocks below our feet.
+
+In this way it will be possible to predict a serious earthquake,
+because it will give warning some days before, by the increase of the
+little tremors and sounds; and it is to be hoped that by this simple
+means human lives may be saved.
+
+Now, these disturbances are of precisely the same nature as
+earthquakes,--in fact, we may call them microscopic earthquakes. To
+the geologist they are of great interest, as they seem to afford
+some little insight into the difficult question of the upheaval of
+mountains, and to show us something of the constant _working_ of
+those wonderful forces below the surface of the earth by means of
+which continents are raised up out of the sea, and mountain-chains
+are elevated thousands of feet. It is probable that both are due to
+the working of the same forces, and are accomplished by the same
+machinery.
+
+We now pass on to consider those more violent movements of the solid
+land known as earthquakes. This kind of disturbance is such as might
+be produced by a sudden shock or blow given below the ground, from
+which waves travel in all directions. First comes a rumbling noise
+like the roar of distant artillery; then come the earthquake waves
+one after another, causing the ground to rise and fall as a ship does
+on the waves of the sea; the ground is frequently rent asunder, so
+that chasms are formed, into which in some cases men and animals
+have been hurled alive. In the case of a very violent earthquake
+the waves travel long distances. Thus the great earthquake by which
+Lisbon was destroyed in the year 1755 disturbed the waters of Loch
+Lomond in Scotland. In this fearful catastrophe sixty thousand human
+beings perished. If the disturbance takes place near the sea, great
+sea waves are formed, which cause fearful destruction to life and
+property. This happened in the case of the Lisbon earthquake; and
+in the year 1868, when Ecuador and Peru were visited by a fearful
+earthquake, a great sea wave swept over the port of Arica, and in a
+few minutes every vessel in the harbour was either driven ashore or
+wrecked, and a man-of-war was swept inland for a quarter of a mile.
+
+Earthquakes bring about many changes on the surface of the earth. For
+example, on mountain-slopes forests are shattered, and large masses
+of soil and débris are shaken loose from the rock on which they
+rested, and hurled into the valleys; streams are thus choked up, and
+sometimes lakes formed, either by the damming up of a river or by
+the subsidence of the ground.
+
+It is frequently found after an earthquake that the level of
+the ground has been permanently altered; and this effect of
+earthquakes is important in connection with the subject we are now
+considering,--namely, how mountains are upheaved. Sometimes, it is
+true, the movement is a downward one; but more generally it takes
+place in an upward direction. As an example of this, we may mention
+the Chilian earthquake of 1835, which was very violent, and destroyed
+several towns on that coast, from Copiapo to Chile. It was afterwards
+found that the land in the Bay of Conception had been raised four or
+five feet. At the island of Santa Maria, to the southwest of this
+bay, the land was raised eight feet, and in one part ten feet; for
+beds of dead mussels were seen at that height above high water, and
+a considerable rocky flat that formerly was covered by the sea now
+became dry land. It was also proved by means of soundings that the
+sea round the island was shallower by about nine feet.
+
+Now the question arises, "How are earthquakes caused?" Various
+suggestions have been made; but it is pretty clear that all
+earthquakes are not produced in the same way. For instance, volcanic
+eruptions are frequently attended by earthquakes. Violent shocks of
+this nature generally precede and accompany a great eruption, as is
+frequently the case before an eruption of Mount Vesuvius.
+
+Steam plays a very important part in all volcanic eruptions; and
+these earthquakes are probably caused by great quantities of pent-up
+steam at a high pressure struggling to escape. It is also possible
+that when molten rock is forcibly injected into the crevices and
+joints of overlying rocks earthquake shocks may be produced by
+the concussion. The old Roman poet and philosopher, Lucretius,
+endeavoured to solve this problem, and concluded that "the shakings
+of the surface of the globe are occasioned by the falling in of
+enormous caverns which time has succeeded in destroying." But
+though the explanation might possibly apply to a few cases of small
+earthquakes, it is not a satisfactory one, for it is not at all
+likely that many large cavities exist below the earth's surface,
+because the great weight of the overlying rock would inevitably crush
+them in.
+
+We have already pointed out that earthquakes frequently happen in
+mountainous regions; and this fact alone suggests that perhaps the
+same causes which upheave mountains may have something to do with
+earthquakes. But there are other reasons for believing that the same
+force which causes earthquakes also upheaves mountain-chains. The
+reader will remember the case of the Chilian earthquake that raised
+part of the Andes a few feet in height.
+
+Now, it is quite clear that the rocks of which mountains are composed
+have suffered a great deal of disturbance. We have only to look at
+the crumbled and contorted strata to see that they have been forced
+into all kinds of positions, sometimes standing bolt upright (see
+diagrams, chap. ix., p. 307). And as we cannot believe, for many
+reasons, that these movements were of a very sudden or violent kind,
+we must consider that they took place slowly on the whole; but
+besides being folded and twisted, the rocks of mountains frequently
+exhibit clear signs of having been split and cracked. The fractures
+are of all sizes, from an inch or more up to hundreds or even
+thousands of feet. They tell us plainly that the rocks were once
+slowly bent, and that after a certain amount of bending had taken
+place, the strain put upon them became greater than they could bear,
+and consequently they snapped and split along certain lines. This is
+just what might be expected. For instance, ice on a pond will bend a
+good deal, but only up to a certain amount; after that, it cracks in
+long lines with a remarkably sharp and smooth fracture. But suppose
+the pressure came from below instead of from above, as when a number
+of people are skating on a pond. Should we not see the ice forced
+up in some places, so that some sheets stood up above the others
+after sliding past their broken edges? This is just what the rocks
+in different places have frequently done. After a fracture has taken
+place the rock on one side has slid up over the other, and the two
+surfaces made by the fracture--like two long walls--are no longer
+seen at the same level. One has been pushed up, while the other has
+gone down (see diagram of the ranges of the Great Basin, chap. viii.,
+p. 273).
+
+Now, it is almost impossible to conceive of these tremendous
+fractures taking place in the rocks below our feet without causing
+sudden jars or shocks. Here, then, we seem to have a clue to the
+problem. Even if the movements took place only a few inches or a few
+feet at a time, that does not spoil our theory, but rather favours
+it; for in that case the upheaval of a mountain-chain will have
+taken a very long time (which is almost certain), and may have been
+accomplished bit by bit. Hundreds and thousands of earthquake shocks,
+some slight, and others severe, may have attended the upheaval of a
+mountain-range.
+
+This explanation is accepted by many authorities. It does not exactly
+imply that mountains were upheaved by earthquakes; but it means that
+the same forces that elevate continents, heaving them up out of the
+sea into ridges and very low arches, have been at work to crumple and
+fold their rocks in some places into stupendous folds, such as we now
+find form part of the general structure of mountains; and that in so
+doing they caused fearful strains, too great for the rocks to bear,
+so that they split over and over again, and in so doing produced jars
+and shocks that must have been very similar to, if not identical
+with, earthquake shocks as we know them at the present day.
+
+Such an explanation is in striking harmony with what we have
+already learned about the operations of Nature. It was from the
+long-continued operation of rain and rivers that the materials now
+forming mountains were transported to the seas in which they were
+slowly formed. It was also by the ordinary operations of frost,
+heat and cold, snow and ice, streams, rain, and rivers that the
+mountains received their present shapes (see chapters v. and vii.).
+And now we learn that the gigantic work of upheaval took place in a
+tolerably quiet and uniform manner,--with perhaps only an occasional
+catastrophe of a more violent kind, but still according to the same
+law of uniformity which is the very basis of modern geology, and by
+means of which so much can be explained.
+
+We could give other proofs of the gradual elevation of mountains
+if they were wanted. But at least enough has been said to give
+the reader a glimpse into the methods employed by geologists in
+endeavouring to explain how mountains were upheaved; and to show that
+it is only by a careful study of all that is taking place now on the
+earth that we can ever hope to solve the difficult questions that
+present themselves to all who study those stony records on which the
+earth has written for our enlightenment the chapters of her ancient
+history.
+
+In conclusion, it may be asked what is the nature of the force that
+accomplishes all this titanic work of upheaval. Although the question
+has been much discussed, and some very ingenious suggestions brought
+forward, we cannot say that any of them are entirely satisfactory.
+But we know that the earth is a cooling body which loses so much heat
+every year; and it may be that the shrinking that takes place as it
+cools, by leaving the crust of the earth in some places unsupported,
+causes it to settle down, to adapt itself to a smaller surface below,
+and in so doing it would inevitably throw itself into a series of
+folds, or wrinkles, like those on the skin of a dried apple. Many
+think that mountain-ranges may be explained in this way.
+
+
+
+
+CHAPTER VII.
+
+HOW THE MOUNTAINS WERE CARVED OUT.
+
+            And surely the mountain fadeth away,
+    And the rock is removed out of its place,
+    The waters wear away the stones:
+    The overflowings thereof wash away the dust of the earth.
+
+    _Job xiv. 18._
+
+
+The mighty fortresses of the earth, which seem so imperishable, so
+majestic in their strength, and have from time immemorial received
+their title of "the everlasting hills," are nevertheless undergoing
+constant change and decay. They cannot abide for ever. Those waste
+leagues around their feet are loaded with the wrecks of what once
+belonged to them; they are witnesses to the victory of the hostile
+forces that are for ever contending with them, and pledges of a final
+triumph. To those who will read their story, mountains stand like old
+dismantled castles, mere wrecks of ruined masonry, that have nearly
+crumbled away, telling us of a time when all their separate peaks
+and crags were one solid mass, perhaps an elevated smooth plateau
+untouched by the rude hand of time.
+
+Let us now inquire how the work of destruction is accomplished.
+Referring back to our illustration of the cathedral, given in chap.
+v., pp. 143-147, the question we have now to consider is, how the
+mountains were carved out into all these wonderful features of crag
+and precipice, peak and pass, which are such a source of delight
+to all who care for scenery. This work we included in the one word
+"ornamentation." What, then, are the tools which Nature uses in this
+work of carving out the hills? What are her axes and hammers, her
+chisels and saws?
+
+This question, like many others, must be answered by observing what
+takes place at the present day. It is scarcely necessary to say that
+mountains and mountain-ranges are not simply the result of upheaval,
+though they have been upheaved. If that were so, they would probably
+appear as long smooth, monotonous ridges, with no separate mountain
+masses, no peaks, no glens or valleys; in some cases they might
+appear as simply elevated and smooth plateaux. Such mountains, if
+we may so call them, would be almost as uninteresting as the roof
+of a gabled house down which the rain finds its way in one smooth
+continuous sheet.
+
+Mountains, reaching as they do into the higher regions of the
+atmosphere, where the winds blow more fiercely than on the plains
+below, storms rage more violently, and the extremes of heat and cold
+are more severe,--in fact, where every process of change and decay
+seems quickened,--suffer continually at the hands of the elements.
+
+   "Death must be upon the hills, and the cruelty of the tempests
+   smite them, and the thorn and the briar spring up upon them;
+   but they so smite as to bring their rocks into the fairest
+   forms, and so spring as to make the very desert blossom as the
+   rose."[23]
+
+  [23] Modern Painters.
+
+Nature never leaves them alone, never gives them a brief armistice in
+the long war that she wages against them. She is a relentless enemy,
+ever on the move, and ever varying her methods of attack. Now she
+assails them openly with her storm-clouds, and pelts them furiously
+with driving rain; now we hear the thunder of her artillery, as she
+pierces their crests with strange electric darts of fire; now she
+secretly undermines their sides with her hidden sources of water,
+till whole villages are destroyed by some fearful fall of overhanging
+rocks (see chapter iii., pages 96-101). Her winds and gentle breezes
+are for ever at work on their surfaces, causing them to crumble into
+dust much in the same way as iron turns to rust.
+
+Again, she heats them by day and then chills them suddenly at night,
+under the cold starry sky, so that they crack under the strain of
+expanding and contracting. Now she splits them with her ice-wedges;
+now she furrows their sides with the dashing torrents and running
+streams; and yet again she wears them gently down with her glaciers,
+and carries away their débris--the token of her triumph--on those icy
+streams, as conquering armies carry the spoils in procession.
+
+This is, briefly, her mode of warfare; these are some of her tools,
+_wind_, _rain_, _frost_, _snow_, _heat_ and _cold_, _streams_,
+_rivers_, and _glaciers_. Lightning does occasionally break off
+portions of a cliff or a mountain-peak; but compared to the others,
+this agent is not very important.
+
+Let us first inquire into the effects produced by the atmosphere.
+The air around us is composed mainly of two well-known gases;
+namely, oxygen and nitrogen. There is also a small proportion (about
+one in ten thousand) of carbonic acid gas; a variable quantity of
+water-vapour, and in the neighbourhood of towns, traces of other
+noxious gases, such as sulphurous acid and chlorine.
+
+Now, the nitrogen plays a very unimportant part, as it merely
+serves to dilute the powerful gas, oxygen, which has such important
+life-sustaining properties. We live by breathing oxygen; so do all
+animals; and the more pure air we can contrive to get into our
+lungs, the better. But undiluted oxygen would be too strong for us,
+and so its strength is diminished by being mixed with four parts of
+nitrogen; that is to say, the air only contains about one fifth by
+volume, or bulk, of oxygen and four fifths of nitrogen.
+
+Now, oxygen, being always ready to combine chemically with some other
+element, is a great agent of change and decay. It attacks all the
+metals except gold and platinum. Iron, we all know, oxidises, or
+rusts, only too quickly; but copper, lead, silver, and other metals
+are more or less attacked by it. So it is with all the rocks exposed
+at or near the surface of the earth. Oxygen will, if it can, pick
+out something to combine with and so bring about chemical changes
+which lead to decay. But a much more powerful agent is the carbonic
+acid gas in the atmosphere; although there is so little of it, there
+is enough to play a very important part in causing rocks to crumble
+away, and in some cases to dissolve them entirely. The supply of this
+gas is continually being renewed, for all living animals breathe out
+carbonic acid, and plants give it out by night. Under the influence
+of sunlight plants give out oxygen, so that gas is supplied to the
+air by day.
+
+Both oxygen and carbonic acid gas are dissolved by rain as it falls
+through the air; and so we cannot separate the effects of the dry
+air by itself from those of rain and mist, which are more important
+agents. The action of rain is partly mechanical, partly chemical, for
+it not only beats against them, but it dissolves out certain mineral
+substances that they contain.
+
+All rocks are mixtures of two or more kinds of minerals, the
+particles of each being often invisible to the naked eye. Thus
+granites are essentially mixtures of felspar, quartz, and mica;
+ordinary volcanic rocks ("trap-rocks") of felspar and augite;
+sandstones consist mainly of particles of silica; limestones of
+carbonate of lime; shales and slates of silicate of alumina, the
+principal substance in clay. These grains are usually joined together
+by a cement of some mineral differing more or less from the other
+particles. Lime is found in many of the rocks as the cement that
+binds their particles together; while oxide of iron and silica serve
+this purpose in many other instances. Now, if the lime or iron or
+silica is dissolved by water, the rock must tend to crumble away. Any
+old building shows more or less manifold signs of such decay, and
+this process is called "weathering." All this applies merely to the
+surfaces of rocks; and if there were no other forces at work, their
+rate of decay would be very slow.
+
+But there are other forces at work. In the first place, sudden
+changes of temperature have a destructive influence. If the sun
+shines brightly by day, the rocks--especially in higher mountain
+regions--are considerably expanded by the heat they receive; and if
+a hot day is followed by a clear sky at night, the free radiation of
+heat into space (see chap. ii., p. 39) causes them to become very
+cold, and in cooling down they contract. In this way an internal
+strain is set up which is often greater than they can bear, and so
+they split and crack. Thus small pieces of rock are detached from a
+mountain-side. An Alpine traveller told the writer that one night
+when sleeping on a mountain-side, he heard stones rattling down at
+frequent intervals. Livingstone records in his journal that when
+in the desert he frequently heard stones splitting at night with a
+report like that of a pistol. But sometimes the expansion by day is
+sufficient to cause fragments of rock to be broken off.
+
+Frost, however, is responsible for a vast amount of destruction among
+rocks. When water freezes, it expands with tremendous force; and this
+is the reason why water-pipes so frequently burst during a frost,
+though we don't find it out until the thaw comes,--followed by long
+plumbers' bills. Rocks, being traversed in several directions by
+cracks, allow the water to get into them, and this in freezing acts
+like a very powerful wedge; and so the rocks on the higher parts of
+the mountains are continually being split up by Nature's ice-wedge.
+
+The amount of rock broken up in this way every year is enormous.
+Stone walls and buildings often suffer greatly from this cause during
+a long frost, especially if the stone be of a more than usually
+porous kind, that can take up a good deal of rain water.
+
+Where trees, shrubs, etc., grow on rocks, the roots find their way
+into its natural divisions, widened by the action of rain soaking
+down into them; and as they grow, they slowly widen them, and in time
+portions are actually detached in this manner. Moreover, the roots
+and rootlets guide the rain water down into the cracks, or joints, as
+they are called. Even the ivy that creeps over old ruined walls has a
+decidedly destructive effect.
+
+At the base of every steep mountain may be seen heaps of loose
+angular stones; sometimes these are covered with soil, and form long
+slopes on which trees and shrubs grow. Every one of the numerous
+little gullies that furrow the mountain-sides has at its lower
+end a similar little heap of stones. Sometimes a valley among the
+mountains seems half choked with rocky fragments; and if these were
+all removed, the valley would be deeper than it is. In some hot
+countries, where the streams only flow in winter, this is especially
+the case; for example, every valley, or "wady," in the region of
+Mount Sinai and Mount Horeb is more or less choked up with boulders
+and stones of every size, because the stones come down faster than
+they can be carried away.
+
+But the main work of carving out the hills and mountains of the
+world is done by streams, rivers, and glaciers; and so we now pass
+on to consider how they perform their tasks. Water by itself, even
+when flowing fast, would be powerless to carve gorges and valleys
+in the solid rock; but the stones which torrents and streams carry
+along give them a marvellous grinding power, for with such material
+a stream continually wears away its rocky bed. Moreover, the stones
+themselves are all the while being rubbed down by each other, until
+finally they are ground down to fine sand and mud, which help in the
+work of erosion.
+
+Every mountain stream or torrent runs in a ravine or valley of some
+sort; and any traveller who will take the trouble to watch what goes
+on there may easily convince himself that the ravine, gorge, or
+valley has been carved out by the stream, aided by the atmospheric
+influences to which we have already alluded.
+
+But perhaps some may be inclined to look upon the ravine as a chasm
+produced by some violent disturbance from below, whereby the rocks
+were rent asunder, and that the stream somehow found its way into the
+rent. A little inquiry will dispel this idea. In the first place,
+such catastrophes are quite unknown at the present day; and as we
+have more than once pointed out, the geologist's method is to apply
+a knowledge of processes now in operation to the phenomena of the
+rocks, in order to read their history. Secondly, no conclusion can be
+accepted which is not supported strongly by evidence.
+
+If such a rending of the rocks had taken place, there would assuredly
+be some evidence of the fact. We should expect to find a great crack
+running all along the bed of the stream; but of this there is no
+sign. Go down in any weather when the stream is low, and look at
+the rocks over which it flows, and you will search in vain for such
+evidence. Instead of being broken, the rocks extend continually
+across. You would also expect to find the strata "dipping," or
+sloping away from the stream on each side, if they had been rent
+by such an upheaval; but here again we are met by a total want of
+evidence. Thirdly, a crack might be expected to run along more or
+less evenly in one direction. But look at the ravine, follow it
+up for some miles, and you will see that it winds along in a very
+devious course, not in a straight line.
+
+For these reasons, then, we must conclude that the ravine or
+valley has been carved out by the stream; but perhaps the most
+convincing arguments are afforded by the furrows and miniature
+ravines so frequently met with on the sides of all mountains; and
+it is impossible to examine these without concluding that they have
+in every case been cut out of the solid rock by the little rapid
+torrents that run along them after heavy rain. If we are fortunate
+enough to see them on a thoroughly rainy day, we may derive much
+instruction from watching the little torrents at work as they run
+down the mountain-side, here and there dashing over the rocks in
+little cascades, and bringing down to the base of the hill much of
+the débris that forms higher up. In this way Nature gives us an
+"object lesson," and seems to say: "Watch me at work here, and learn
+from such little operations how I work on a larger scale, and carve
+out my ravines and big valleys. Only give me plenty of time, and I
+can accomplish much greater feats than this."
+
+The question of time is no longer disputed; and all geologists are
+willing to grant almost unlimited time, at least periods of time that
+seem to us unlimited. Most streams have been flowing for thousands
+of years; and when once we grant that, we find no difficulty in
+believing that all valleys are the work of rain and rivers. Surely
+no one would argue that the furrows on a mountain-side are all rents
+which have been widened by the action of water; for if they were
+rents, each must have been caused by some disturbance of the rocks
+composing the mountain, and we should of course be able to see the
+cracks for ourselves, and to find that the rocks had in some way been
+disturbed and rent open.
+
+Even the rain which falls on the road in a heavy shower teaches the
+same simple but important lesson, as it runs off into the gutters
+on each side; and we may often find the road furrowed by little
+miniature rivers, that carve out for themselves tiny valleys as they
+run off into the gutter, bringing with them much débris in the form
+of mud and sand.
+
+Sometimes a stream encounters in its course a layer of rock that is
+harder than the rock underlying it. In this case the softer rock
+is worn away faster, and the hard layer forms a kind of ridge at a
+higher level; the result is a waterfall. Waterfalls are frequently
+found in mountain streams. In this case, it is easy to trace the
+ridge of harder rock running unbroken across the path of the stream,
+showing clearly that it has not been rent in any way. First it showed
+merely as a kind of step, but gradually the force of the falling
+water told with greater effect on the softer rock below, wearing it
+away more rapidly than that above, and so the depth of the waterfall
+went on increasing year by year; and at the same time the hard layer
+was slowly worn away until the stream sawed its way through.
+
+Some river valleys are steep and narrow; others are broad, with
+gently sloping sides. A careful study of the different valleys in
+any large country such as Great Britain, shows that their forms vary
+according to the nature of the rocks through which rivers flow. Where
+hard rocks abound, the valleys are steep and narrow; where soft rocks
+occur, the valleys are broad and low. This is only what might be
+expected, for hard rocks are not easily worn away; a river must cut
+its way through them, leaving cliffs on either side that cannot be
+wasted away by rain. But in a district where clay or soft sandstone
+occurs, the rain, as it finds its way to the valley, will wash them
+away and give a smooth gentle slope to the sides of the valley.
+
+It is very instructive to notice how the scenery of any district
+depends on the nature of its prevailing rocks. Hard rocks give bold
+scenery with steep hills and rocky defiles; while soft rocks make the
+landscape comparatively flat and tame, though often very beautiful
+in its way, especially where a rich soil abounds, so that we see
+pleasant woods, rich pasture-land, and heavy crops in the fields.
+
+Compare, for instance, the scenery of Kent or Surrey with that
+of the Lake District or the west of Yorkshire. The difference
+is due chiefly to the fact that in Kent and Surrey we have rocks
+that succumb more easily to the action of rain and rivers, and
+consequently are worn away more rapidly than the harder rocks in the
+north country. Geologists have a word to express the effects of this
+wear and tear; namely, "denudation," which means a stripping off, or
+laying bare.
+
+In Kent and Surrey the agents of denudation (rain and rivers, aided
+by the effects of the air, of heat and cold, and so on) wear away the
+whole surface of the county in a tolerably even and uniform manner,
+because there are no hard rocks for them to contend with. In this
+case rain washes away the sides of the valleys faster than the river
+can carve its bed, consequently the valleys are shallow compared to
+their width. And so the streams have broad valleys, while the hills
+are smooth and gently rounded. Chalk, clay, and soft sandstone abound
+there. The two latter rocks are washed away with comparative ease,
+and the chalk is dissolved; whereas in the Lake District we have very
+much harder and older rocks, that require to be split up and broken
+by the action of frost, while every stream carves out for itself a
+steep valley, and great masses of hard rock stand out as bold hills
+or mountains, that seem to defy all the agents of denudation. Here
+the opposite is the case, and the valleys are deepened faster than
+they are widened. But for all that, a vast amount of solid rock has
+been removed from the surface there, of which the mountains are, as
+it were, but fragments that have escaped the general destruction.
+Moreover, the rocks in this region have been greatly disturbed and
+crumpled since they were first formed, and thereby thrown into
+various shapes that give certain peculiar structures more or less
+capable of resisting denudation.
+
+Very effective illustrations of the power of rain by itself are
+afforded by the "earth pillars" of the Tyrol, and "cañons" of
+Colorado. The material of which they consist is called conglomerate,
+because it is composed of stones and large blocks of rock with stiff
+earth or clay between. All the taller ones have a big stone on the
+top which protects the softer material below from being washed away
+by heavy rains; and it is easily perceived that each pillar owes its
+existence to the stone on the top, which prevents the soft materials
+below it from being washed away. When, after a time, the weathering
+of the soft strata diminishes the support of the capping boulders,
+these at last topple over, and the pillar, thus left unprotected,
+becomes an easy prey to the rain, and is rapidly washed away. Some
+of the pillars are over a hundred feet in height. But it is only in
+places where heavy rains fall that these interesting monuments of
+denudation are to be seen.
+
+By way of contrast we may turn now to a district in which very little
+rain falls, but where the streams have a considerable slope, and so
+can wear away, or erode, their valleys much faster than rain and
+frost, etc., can bring down the rocks of which the sides are composed.
+
+The river Colorado of the West, which runs from the Rocky Mountains
+to the Gulf of California, flows for nearly three hundred miles at
+the bottom of a profound chasm, or cañon, being hemmed in by vertical
+walls which in some places are more than a mile in depth. The
+tributary streams flowing into the river run through smaller ravines
+forming side cañons; and there is no doubt that these wonderful
+chasms have been, in the course of ages, slowly carved out by the
+river Colorado and its numerous tributary streams. Sometimes the
+walls of the cañon are not more than fifty yards apart, and in height
+they vary from three thousand to six thousand feet.
+
+Far above the level of the highest floods patches of gravel are found
+here and there on the sides, which must have been left there by the
+river when it had not cut its way so far down. These cañons afford
+striking testimony to the erosive power of running water, of which
+they are the most wonderful illustration in the world.
+
+But water, even when in the form of ice, has more or less power to
+wear away solid rock; and the glaciers that we see in Switzerland,
+Norway, and other countries must slightly deepen the rocky valleys
+down which they flow. Let us see how this can be accomplished.
+
+The snow that falls in the High Alps, impelled by the weight of fresh
+layers of snow overlying it, and by the slope of the mountain-sides,
+gradually creeps down into the valleys. Owing to the pressure thus
+put upon it, and partly to the melting power of the sun's rays, it
+assumes the form of ice; and glaciers are composed of solid ice. The
+downward motion is so slow that a glacier appears quite stationary;
+and it is only by putting in stakes and watching them change their
+positions that it can be shown to be moving.
+
+In all respects except speed, glaciers flow like rivers, for ice is
+a viscous body, behaving partly like a fluid and yet partly like
+a solid substance; but it will not endure a sharp bend without
+snapping. Hence, a glacier in traversing a valley frequently gets
+split. The cracks thus formed widen by degrees until they expand
+into chasms, or "crevasses." Like rivers, glaciers transport a large
+amount of rocky matter to lower levels, and at the same time wear
+away and deepen their rocky channels.
+
+Let us see how they do this twofold work of transportation and
+erosion. In the first place, a large amount of débris falls onto the
+sides of a glacier from the peaks, precipices, and mountain-side
+along which it flows. Some stones, however, fall down crevasses, and
+so reach the bottom, where they become cemented in the ice. In this
+way they are slowly carried down over the rocky floor of the valley,
+until at last they reach the end of the glacier, where in the warmer
+air the ice melts just as fast as it creeps down; and there they will
+be left to form a heap of stones, sand, and mud.
+
+Large blocks of stone, quite different from the rocks on which they
+lie, are very numerous, and are called "erratics," since they are
+evidently wanderers from a distance. Sometimes such blocks can be
+proved to have been brought many miles from their home among the
+higher peaks. The long lines of stones and mud seen on the sides of
+a glacier are called "moraines," and at the end of every glacier we
+find a big heap known as a "terminal moraine." But the stones of
+which they are composed are probably not to be entirely accounted
+for in this way. Can we not conceive that the weight and pressure of
+a descending glacier may be sufficient to break off many protruding
+portions of the rocky bed over which it flows, and then to drag them
+along with it? This seems reasonable. Let us therefore consider
+the materials of which moraines are composed to be derived partly
+from the rocks beneath and partly from those above the glacier. But
+whatever their origin, such materials must inevitably find their way
+to the end of the glacier and be added to the big heap there. The
+work of transportation is then taken up by the stream which always
+flows from the end of a glacier. Such streams are in summer-time
+laden with fine sediment, which gives them a milky and turbid
+appearance.
+
+Thus a glacier wears away the rocks over which it flows; rock
+fragments become embedded in the ice, and these are the tools with
+which a glacier does its work. It must be granted that the downward
+movement of a great mass of ice is irresistible, and consequently
+that as the moving glacier slowly creeps along, it must inevitably
+cause the stones which it thus holds to grind over the surface of
+the rock. It is easy to imagine the effects of this grinding action.
+If sand-paper, rubbed for a minute or two over wood, wears down and
+smooths its surface, what must be the result of all these stones,
+together with sand and mud, grinding over the rocky bed?
+
+The answer to this question is found in examining the rocks over
+which glaciers once flowed. Now, the Swiss glaciers once extended
+far beyond their present limits; and the rocks in the lower parts of
+their present valleys, now free from ice, show unmistakable signs
+of having been considerably worn down. The corners and angles of
+projecting pieces of rock have been worn away until the once rugged
+outline has become wavy and round, so much so as to produce more or
+less resemblance to the backs of sheep lying down. Hence the name
+_roches moutonnées_, by which rocks of this shape are known. They
+frequently retain on their surface peculiar markings, such as long
+scratches and grooves which must have been made as the old glacier,
+with its embedded angular fragments of rock, slowly ground over
+their surfaces. Such markings are called "striæ." But besides these
+glacial records graven on the rocks, we have other evidence, in the
+form of great moraines in some of the valleys of Switzerland, and
+especially at those places where side valleys open out into a main
+valley. Any one may learn by a little observation to recognise these
+peculiar heaps of stones, mud, and sand, deposited long ago by the
+old glaciers of Switzerland.
+
+It will be perceived that the evidence for the erosive power of
+glaciers is of two kinds,--first, there is the testimony of the
+smoothed and striated rocks, which is very convincing; secondly,
+the equally strong proofs from the moraines, both great and small.
+These old rubbish heaps give us a very fair idea of the amount of
+wear and tear that goes on under a glacier, for there we see the rock
+fragments that tumbled down the mountain-side onto the surface of the
+glacier (together with those which the glacier tore off its rocky
+bed), all considerably smoothed, worn down, and striated. But a still
+better idea of the work done is afforded by the gravel, mud, and sand
+in which these stones are embedded. All this finer material must have
+been the result of wear and tear. This kind of action may well be
+compared to what takes place on a grindstone as one sharpens an axe
+on it. The water poured on the stone soon becomes muddy, owing to the
+presence of countless little grains of sand worn off the grindstone.
+But a good deal of the mud thus formed is carried away by the little
+stream that runs out from the end of every glacier; so that there is
+more formed than we see in the moraine.
+
+  [Illustration: THE MER DE GLACE AND MONT BUET. FROM A PHOTOGRAPH
+  BY MR. DONKIN.]
+
+We have already alluded in former chapters to the "Ice Age" in
+Britain, when great glaciers covered all our high mountains, and
+descended far and wide over the plains. Now, the evidence for the
+former existence of these glaciers is of the same kind as that which
+we have just described. In Wales and Scotland we may soon learn
+to recognise the _roches moutonnées_, the old moraine heaps, and
+the erratic boulders brought down by these old glaciers. Besides
+these proofs, there is also the evidence of the arctic plants now
+flourishing in the highlands (see chapter iv., pages 123-124).
+
+There can be no doubt, then, that glaciers have an erosive action,
+and therefore must be regarded as agents of denudation. But it is
+important to bear in mind that their powers in this direction are
+limited; for it is manifest that a mountain stream is a much more
+powerful agent, and will deepen its little valley much more rapidly,
+than a cumbrous, slow-moving glacier, advancing at the rate of a
+few inches a day. It has been found by careful measurements that
+the Mer de Glace of Chamouni moves during summer and autumn at the
+average daily rate of twenty to twenty-seven inches in the centre,
+and thirteen to nineteen and one half inches near the side, where
+friction somewhat impedes its course. This seems very slow compared
+to the rapid movement of a mountain stream; but then, a glacier
+partly makes up for this by its great weight.
+
+In considering a glacier as an agent of erosion, we must not forget
+that probably a good deal of water circulates beneath glaciers. If
+this is so, the water must have a considerable share in producing the
+effects to which we have already alluded. It would be extremely rash
+to conclude, as some students of glaciers have done, that valleys
+can be carved out _entirely_ by glaciers; and we must be content
+with believing that they have been somewhat deepened by ice-action,
+and their features more or less altered, but no more. The valleys of
+Switzerland, of Wales, and Scotland, were probably all in existence
+before the period of the "Ice Age," having been carved out by streams
+in the usual way; but the glaciers, as it were, put the final touches
+and smoothed their surfaces.
+
+Having learned how the three agents of denudation--namely, rain,
+rivers, and glaciers--accomplish their work, let us now take a wider
+view of the subject and consider the results of their united efforts
+both in the present and in the past.
+
+We have already alluded to the enormous amount of solid matter
+brought down to the sea every year by rivers (see chap. v., pp.
+166-168), and we pointed out that all this represents so much débris
+swept off the land through which the rivers flow; also that it comes
+down in three ways, one part being suspended in the water as fine
+mud, another part being pushed along the river-bed as gravel, etc.,
+while a third part is the carbonate of lime and other mineral matter
+in a dissolved state, and therefore invisible.
+
+Now, it is quite plain that rain and rivers, in sweeping away so much
+solid matter from the surface of the land, must tend in the course
+of time to lower its general level; and it therefore seems to follow
+that after the lapse of ages any given continent or large island
+might be entirely washed away, or in other words, reduced to the
+level of the sea. This would certainly happen were it not that the
+lands of the world seem to be slowly rising, so that the denudation
+going on at the surface appears to be counterbalanced by continued
+upheaval.
+
+But, supposing no upheaval took place, how long would it take for
+rain and rivers to wear away a whole continent? Let us see if there
+is any way of answering this difficult question, for if it can be
+even partially solved, it will help us to realise the enormous length
+of time that must have been required to bring about the results of
+denudation that we see all around us.
+
+Although the calculations that have been made on this subject are
+very complicated, yet the principle on which they are based is quite
+simple. For an answer to our question we must go to the rivers again,
+and measure the work they do in transporting solid matter down to
+the sea. Let us take the Mississippi as a typical big river, for
+it has been more carefully studied than any other, and it drains a
+very extensive area, embracing many varieties of climate, rock, and
+soil. As the result of many observations carried on continuously at
+different parts of the river for months together, the engineers who
+conducted the investigation found that the annual discharge of water
+by this river is about nineteen thousand millions of cubic feet,
+and that on the average the amount of sediment it contains is about
+a 1/1500th part by weight. But besides the matter in suspension,
+they observed that a large amount of sand, gravel, and stones is
+being constantly pushed along the bottom of the river. This they
+estimated at over seven hundred and fifty millions of cubic feet.
+They also calculated that the Mississippi brings down every year
+more than eight hundred thousand million pounds of mud. Putting the
+two together, they found (as before stated) that the amount of solid
+matter thus transported down to the Gulf of Mexico may be represented
+by a layer 268 feet high, covering a space of one square mile; that
+is, without allowing for what is brought down dissolved in the water,
+which may be neglected in order to prevent any exaggeration.
+
+Now, it is quite clear that all this débris must have come from the
+immense area that is drained by the Mississippi. It could not have
+been supplied by any rivers except those that are its tributaries.
+And so if we can find out what is the extent of this area, it is not
+difficult to calculate how much its general surface must have been
+lowered, or in other words, how much must have been worn away from
+it in order to supply all the material. This area is reckoned at
+1,147,000 square miles; and a very simple calculation tells us that
+the general surface would thus be lowered to the extent of 1/6000th
+part of a foot. That of course means that one foot would be worn away
+in six thousand years. On high ground and among mountains the rate of
+denudation would of course be much greater; but we are now dealing
+with an average for the whole surface.
+
+The next thing we require to finish this calculation is the average
+or mean height of the American continent. This was reckoned by the
+celebrated Humboldt at 748 feet. Now if we may assume that all this
+continent is being worn down at the same rate of one foot in six
+thousand years (which is a reasonable assumption), we find, by a
+simple process of multiplication, that it would require about four
+and a half millions of years for rain and rivers to wash it all away
+until its surface was all at the sea-level (with perhaps a few little
+islands projecting here and there as relics of its vast denudation).
+This is a very interesting result; and if the above measurements are
+reliable, they afford us some idea of the rate at which denudation
+takes place at the present time.
+
+By a similar process it has been calculated the British Isles might
+be levelled in about five and a half millions of years. Geologists
+do not pretend to have solved this problem accurately; that is
+impossible with our present knowledge. But even as rough estimates
+these results are very valuable, especially when we come to study
+the structure of the land in different countries, and to find out
+therefrom, by actual measurement, how much solid rock has been
+removed. We will now give some examples of this; but perhaps a simple
+illustration will make our meaning clearer.
+
+Suppose we picked up an old pair of boots, and found the soles worn
+away in the centre. It would be easy to find out how much had been
+worn away over the holes by simply measuring the thickness of leather
+at the sides, where we will suppose that they were protected by
+strong nails. Geologists apply a very similar kind of method in order
+to find out how much rock has been removed from a certain region of
+the earth. One of the simplest cases of this kind is that of the area
+known as the Weald of Kent, Surrey, and Sussex (see illustration,
+Fig. 1). A great deal of denudation has taken place here, because
+there is ample evidence to prove that the great "formation" known
+as the Chalk (now seen in the North and South Downs) once stretched
+right across; and below this came the lower greensand and Weald clay.
+They spread over this area in a low arch of which we now only see the
+ruins.
+
+  [Illustration: Fig. 1. SECTION ACROSS THE WEALD OF KENT AND
+  SURREY.]
+
+  [Illustration: Fig. 2. THE HIGHLANDS OF SCOTLAND ON A TRUE SCALE
+  (after GEIKIE).]
+
+The dotted lines in the figure show us their former extent; but
+the vertical height is exaggerated, for otherwise the hills would
+scarcely be seen.
+
+These lines simply follow out the curves taken by the strata at each
+end of the denuded arch, and therefore rightly indicate its former
+height. By making such a drawing on a true scale, geologists can
+easily measure the former height of the surface of this old arch,
+or "anticline," of chalk, greensand, and other strata, just as an
+architect might restore the outlines of an old traceried window from
+a few portions left at the sides.
+
+This very useful and instructive method is much employed in drawing
+sections through mountain-chains, in order to gain some idea of the
+amount of denudation which they have suffered.
+
+Let us see how much has been removed from the present surface of
+the Weald. First there is the chalk, which we may put down at six
+hundred feet at least; then there is the lower greensand, say, eight
+hundred feet; and below that, and forming the lowest ground in the
+Weald, is the Weald clay, which is one thousand feet thick, and being
+softer, was more rapidly borne away. Along the centre runs a ridge
+of Hastings sand, forming higher ground on account of its greater
+hardness, but this formation is not much denuded. However, adding
+together the thicknesses of the others, we arrive at the conclusion
+that about twenty-four hundred feet of chalk and other strata has
+been removed from the present surface of the Weald. And all this
+denudation has probably been effected by rain and rivers, for it is
+very doubtful whether the sea had any share in this work.
+
+But in other parts of our own country we find proofs of denudation
+on a much grander scale than this; for example, in North Wales there
+are rocks now lying exposed at the surface which are of a very much
+greater antiquity than any that may be seen in the Wealden area,
+belonging to the very ancient periods known as the Cambrian and
+Silurian. These have evidently been exposed for a much longer time
+to the action of denuding forces; and the Welsh hills, as we now
+see them, are but fragments of what they once were. After carefully
+mapping out the rocks in the neighbourhood of Snowdon, noting their
+thickness, the directions in which they slope, or "dip," so that
+the structure of this region might be ascertained, as in the case
+of the Weald, it was found, on drawing sections of the rocks there,
+and putting in dotted lines to continue the curves and slopes of the
+strata as known at or near the surface, that from fifteen thousand
+to twenty thousand feet of solid rock must have been removed (see
+diagrams, chapter ix., p. 307). Applying the same method to the Lake
+District, it has been calculated that the amount of denudation which
+that beautiful country has suffered may be represented by twenty-six
+thousand feet. Turning to the other side of the Atlantic, we find
+the American geologists estimate that a thickness of five miles has
+been removed from a large part of the Appalachian chain of mountains
+(near their east coast), and that at least one mile has been eroded
+from the entire region between the Rocky and Wahsatch Mountains (see
+chapter ix.).
+
+In conclusion, we must bear in mind that mountains, in spite of the
+enormous erosion they have suffered, are more capable of resisting
+the ever active agents of denudation than the softer rocks that form
+the plains and lowlands, and consequently stand out in bold relief
+from other features of the earth's surface. This truth has been
+beautifully expressed in the following passage:--
+
+   " ... In order to bring the world into the form which it now
+   bears, it was not mere sculpture that was needed; the mountains
+   could not stand for a day unless they were formed of materials
+   altogether different from those which constitute the lower
+   hills and the surfaces of the valleys. A harder substance had
+   to be prepared for every mountain-chain, yet not so hard but
+   that it might be capable of crumbling down into earth, fit to
+   nourish the Alpine forest and the Alpine flowers; not so hard
+   but that in the midst of the utmost majesty of its enthroned
+   strength there should be seen on it the seal of death, and the
+   writing of the same sentence that had gone forth against the
+   human frame, 'Dust thou art and unto dust thou shalt return.'
+   And with this perishable substance the most majestic forms were
+   to be framed that were consistent with the safety of man, and
+   the peak was to be lifted and the cliff rent as high and as
+   steeply as was possible, in order yet to permit the shepherd
+   to feed his flocks upon the slope, and the cottage to nestle
+   beneath their shadow."[24]
+
+  [24] Modern Painters.
+
+
+
+
+CHAPTER VIII.
+
+VOLCANIC MOUNTAINS.
+
+    'Tis said Enceladus' huge frame,
+    Heart-stricken by the avenging flame,
+    Is prisoned here, and underneath
+    Gasps through each vent his sulphurous breath;
+    And still as his tired side shifts round,
+    Trinacia echoes to the sound
+    Through all its length, while clouds of smoke
+    The living soul of ether choke.
+
+    VIRGIL: _Æneid iii._
+
+
+In some parts of the world we meet with mountains of a very different
+kind from any we have yet considered,--mountains that are known
+at times to send forth fiery streams of glowing lava, and to emit
+with terrific force great clouds of steam. Such mountains have
+long been known, in popular but unscientific language, as "burning
+mountains,"[25]--a term which is unfortunate, because they do not
+burn in the proper sense of the word, like candles or gas-jets. They
+are better known as volcanoes. There are about three hundred and
+fifty known active volcanoes; and if we include all mountains that
+once were in that state, the number is about one thousand.
+
+  [25] See papers by the writer on Volcanoes and Volcanic Action
+  in "Knowledge" for May and June, 1891, on which this chapter is
+  partly based.
+
+Such mountains are connected in a curious way with those upheaved
+ridges of the world known as mountain-chains (see chap. vi., p.
+191). And not only are many mountains more or less penetrated and
+intersected by rocks of an igneous origin (see chap. v., p. 155),
+but some have been largely formed by the action of old volcanoes.
+In fact, there are hills in Great Britain and parts of Europe, in
+America, and other countries, that once were actual volcanoes (see
+page 277).
+
+We must briefly consider these strange mountains so different from
+others, and see what we can find out about them. Let us first inquire
+how a volcano is made, then consider what a volcano does; that is, we
+must view it as a geological agent that has a certain definite part
+to play in the economy of the world. And lastly, we may glance at
+some of the old volcanoes, and see what they were doing in those long
+ages of the world during which the great series of the stratified
+rocks were formed,--which rocks are, as it were, the book in which
+the earth has written her autobiography.
+
+In old days volcanoes were regarded with superstitious awe; and any
+investigation of their actions would have been considered rash and
+impious in the highest degree. Mount Etna, as Virgil tells us, was
+supposed to mark the spot where the angry gods had buried Enceladus,
+one of the rebellious giants. Volcano, a certain "burning mountain"
+in the Lipa Islands, was likewise called the forge, or workshop,
+of Vulcan (or Volcan), the god of fire. And so it comes about that
+all "burning mountains" take their name from this one Mediterranean
+island, and at the same time tell us of the mythological origin of
+the word. It has been said that words are "fossil thoughts;" and we
+have here an old and very much fossilised thought,--a kind of thought
+long since extinct among civilised peoples, and one which is never
+likely to come to life again.
+
+A volcanic mountain consists of alternating sheets of lava and
+volcanic ashes, mantling over each other in an irregular way,
+and all sloping away from the centre. In the centre is a pit or
+chimney, widening out towards the top so as to resemble a funnel or
+cup; hence the name "crater," which means a cup. In the centre of
+this crater a very small cone ("minor cone") is frequently found;
+and it is interesting to find that many of the moon's volcanic
+craters possess these "minor cones." A number of cracks or fissures
+intersect the volcano. These frequently spread out from the centre
+of the mountain in all directions, like the spokes of a wheel.
+They generally get filled with lava that wells up from below, thus
+forming "dykes," which may be regarded as so many sheets of igneous
+rock, such as basalt, that have forced their way while still liquid
+in among the layers of lava and ashes. The word "ash" is used by
+geologists in a special sense; and volcanic ash is not, as might
+be supposed, a deposit of cinders, but mostly of dust of various
+degrees of fineness, and sometimes it is very fine indeed. Pieces
+of pumice-stone may be embedded in a layer of volcanic ash, and
+sometimes great blocks of stone that have been shot out of the
+volcano as from a big gun, but these only form a small part of the
+layer. Dykes strengthen the mountain, and tend to hold it together
+when violently shaken during an eruption.
+
+The shape and steepness of a volcano depend on the nature of the
+materials ejected. The finer the volcanic ash, the steeper and more
+conical is the mountain. The building up of a volcano may be fairly
+illustrated by the little cone of sand formed in an hourglass as the
+sand-grains fall. These settle down at a certain slope, or angle,
+at which they can remain, instead of falling down to the bottom, as
+they do directly this slope is exceeded. Some volcanoes are built up
+almost entirely of volcanic ash and its embedded blocks. Vesuvius,
+Teneriffe, Jorullo, in Mexico, and Cotopaxi, in the Andes, are
+examples of steep volcanic cones built up in this way. Others, less
+steep and more irregular in shape, are chiefly formed of successive
+lava-flows. Little minor cones are frequently formed on the side of
+a volcano; and these during an eruption give rise to small outbursts
+of their own. They are easily accounted for by the dykes which are
+mentioned just now; for when molten rock forces its way through
+fissures, it sometimes finds an outlet at the surface, and being full
+of steam, as soda-water is full of gas, it gives rise to an eruption.
+The great opening in the centre of a volcano, with its molten lava,
+is like a very big dyke that has reached the surface and so succeeded
+in producing an eruption.
+
+The opening of a soda-water bottle not infrequently illustrates a
+volcanic eruption; for when the pent-up carbonic acid cannot escape
+fast enough, it forces out some of the water, even when the bottle is
+held upright.
+
+Every volcano has been built up on a platform of ordinary stratified
+rocks; and at some period _after_ these had been laid down in water
+and raised up into dry land, molten rock found its way through them,
+and so the volcano was built up by successive eruptions during many
+years. It is probable that earthquake shocks, preceding the first
+eruption, cracked up these strata, and so made a way for the lava to
+come up.
+
+The main point we wish to emphasize is that _volcanoes are never
+formed by upheaval_. In this way they differ from all other
+mountains. They have not been made by the heaving up of strata, but
+have been gradually piled up, something like rubbish heaps that
+accumulate in the Thames barges as the dustmen empty their carts into
+them, only in the case of volcanoes the "rubbish" comes from below.
+It is not necessary to suppose that the reservoir down below, from
+which the molten rock is supplied, exists at any very great depth
+below the original land surface on which the volcano grows up.
+
+The old "upheaval theory" of volcanoes, once advocated by certain
+authorities, instead of being based on actual evidence or on
+reasoning from facts, was a mere guess. Moreover, if the explanation
+we have given should not be sufficiently convincing, there is good
+proof furnished by the case of a small volcano near Vesuvius, the
+building of which was actually witnessed. It is called Monte Nuovo,
+or the New Mountain. It is a little cone 430 feet high, on the bank
+of Lake Averno, with a crater more than a mile and a half wide at the
+base. It was almost entirely formed during a single night in the year
+1538, A. D. We have two accounts of the eruption to which it owes
+its existence; and each writer says distinctly that the mountain was
+formed by the falling of stones and ashes.
+
+
+One witness says,--
+
+   "Stones and ashes were thrown up with a noise like the
+   discharge of great artillery, in quantities which seemed as if
+   they would cover the whole earth; and in four days their fall
+   had formed a mountain in the valley between Monte Barbaro and
+   Lake Averno, of not less than three miles in circumference, and
+   almost as high as Monte Barbaro itself,--a thing incredible
+   to those who have not seen it, that in so short a time so
+   considerable a mountain should have been formed."
+
+
+Another says,--
+
+   "Some of the stones were larger than an ox. The mud (ashes
+   mixed with water) was at first very liquid, then less so, and
+   in such quantities that with the help of the afore-mentioned
+   stones a mountain was raised one thousand paces in height."
+
+(The writer's astonishment led him greatly to exaggerate the height.)
+
+These accounts are important as showing how in a much longer time
+a big volcano may be built up. From such small operations we learn
+how Nature works on a large scale. The great volcano in Mexico known
+as Jorullo was probably built up in a very similar way. There is a
+tradition among the natives that it was made in two or three days;
+but we can hardly believe that. Volcanoes, as they get older, tend
+to grow taller and bigger; but every now and then a large portion may
+be blown away by some great eruption, and they have, as it were, to
+begin again.
+
+  [Illustration: THE ERUPTION OF VESUVIUS IN 1872. FROM AN
+  INSTANTANEOUS PHOTOGRAPH.]
+
+Let us now consider volcanoes as geological agents, and see what
+they do. A volcanic eruption may be described in a general way
+as follows: Its advent is heralded by earthquakes affecting the
+mountain and the whole country round; loud underground explosions
+are heard, resembling the fire of distant artillery. The vibrations
+are chiefly transmitted through the ground; the mountain seems
+convulsed by internal throes, due, no doubt, to the efforts of the
+imprisoned steam and liquid rock to find an opening. These signs are
+accompanied by the drying up of wells and disappearance of springs,
+since the water finds its way down new cracks in the rocks, caused
+by the frequent shocks and quiverings. When at last an opening has
+been made, the eruption begins,--generally with one tremendous
+burst that shakes the whole mountain down to its foundations. After
+this, frequent explosions follow with great rapidity and increasing
+violence, generally from the crater. These are indicated by the
+globular masses of steam which are to be seen rising up in a tall
+column like that which issues from the funnel of a locomotive. But
+sometimes the whole mountain seems to be more or less engaged in
+giving out steam, and thus to be partly enveloped in it. This is
+illustrated by our engraving from an instantaneous photograph of
+Vesuvius in eruption in the year 1872. The steam and other gases, in
+their violent ascent, hurl up into the air a great deal of solid rock
+from the sides of the central opening, after first blowing out the
+stones which previously stopped up the orifice.
+
+Blocks of stone falling down meet with others coming up; and so a
+tremendous pounding action takes place, the result of which is that
+great quantities of volcanic dust and ashes are produced, generally
+of extreme fineness. Winds and ocean currents transport these light
+materials for long distances. The observations made during the
+famous and fruitful voyage of H. M. S. "Challenger" showed that
+fine volcanic dust is carried by wind and marine currents to almost
+all parts of the oceans. The darkness so frequently mentioned in
+accounts of eruptions--sometimes at a very great distance from the
+volcano--is entirely caused by clouds of volcanic dust hiding the
+light of the sun. Perhaps the best example of this is the case of the
+eruption of Krakatoa (in the Strait of Sunda, between Sumatra and
+Java) in 1883. Its explosions were heard in all directions for two
+thousand miles, and a perceptible layer of volcanic dust fell at all
+places within one thousand miles; while the finest dust and vapour,
+shot up fifteen or twenty miles high, were spread all over the globe,
+causing, while still suspended in the atmosphere, the peculiar red
+sunsets noticed in all parts of the world for some months after the
+eruption.
+
+Again, those very curious deposits of "red clay" found in the very
+deepest parts of the Pacific and Atlantic oceans (at depths of about
+four thousand fathoms, or twenty-four thousand feet) have been shown
+to be chiefly composed of volcanic dust, their red colour being due
+to oxidised iron.
+
+But there is another way in which a good deal of fine volcanic dust
+is made; and it is this: the lava is so full of steam intimately
+mixed up with it that the steam, in its violent effort to escape,
+often blows the lava into mere dust.
+
+Another interesting phenomenon may be thus described: Portions of
+liquid, or half liquid, lava are caught up by the steam and hurled
+into the air. These assume a more or less round form, and are known
+as "bombs." At a distance they give rise to the appearance of
+flames. And here we may remark that the flaring, coloured pictures
+of Etna or Vesuvius in eruption, which frequently may be seen, are
+by no means correct. The huge flames shooting up into the air are
+quite imaginary, but are probably suggested by the glare and bright
+reflection from glowing molten lava down in the crater.
+
+So great is the force of the pent-up steam trying to escape that it
+frequently blows a large part of the volcano bodily away; and in some
+cases a whole mountain has been blown to pieces.
+
+Finally, torrents of rain follow and accompany an eruption,--a result
+which clearly follows from the condensation of large volumes of
+steam expanding and rising up into the higher and cooler layers of
+the atmosphere. Vast quantities of volcanic ash are caught up by the
+rain, and in this way very large quantities of mud are washed down
+the sides of the mountain.
+
+Sometimes the mud-flows are on a large scale, and descending with
+great force, bury a whole town. It was mostly in this way that the
+ancient cities of Herculaneum and Pompeii were buried by the great
+eruption of Vesuvius in the year 79 A. D., in which the elder Pliny
+lost his life. The discoveries made during excavations at Pompeii are
+of very great interest as illustrating old Roman life. The Italians
+give the name _lava d'acqua_, or water-lava, to flows of this kind,
+and they are greatly dreaded on account of their great rapidity. An
+ordinary lava-stream creeps slowly along, so that people have time
+to get out of the way; but in the case of mud-flows there is often
+no time to escape. No lava-stream has ever reached Pompeii since it
+was first built, although the foundations of the town stand upon an
+old lava-flood. Herculaneum is nearer to Vesuvius, and has at times
+been visited by lava-streams. Mud-lavas, ashes, and lava-streams have
+accumulated over this city to a depth of over seventy feet.
+
+Lava-streams vary greatly in size; in some cases the lava, escaping
+from craters, comes to rest before reaching the base of the slopes of
+the volcano; in other cases a lava-flow not only reaches the plains
+below, but extends for many miles over the surrounding country.
+Hence lava-streams are important geological agents. Let us look at
+some famous instances. The most stupendous flow on record was that
+which took place from Skaptar Jökull in Iceland, in the year 1783.
+In this case a number of streams issued from the volcano, flooding
+the country far and wide, filling up river gorges which were in some
+cases six hundred feet deep and two hundred and fifty feet broad, and
+advancing into the alluvial plains in lakes of molten rock twelve to
+fifteen miles wide and one hundred feet deep. Two currents of lava
+which flowed in nearly opposite directions spread out with varying
+thickness according to the nature of the ground for forty and fifty
+miles respectively. Had this great eruption taken place in the south
+of England, all the country from the neighbourhood of London to
+that of Gloucester might have been covered by a flood of basalt of
+considerable thickness.
+
+Sometimes, when the lava can only escape at a point low down on the
+mountain, a fountain of molten rock will spout high into the air.
+This has happened on Vesuvius and Etna. But in an eruption of Mauna
+Loa, in the Sandwich Islands, an unbroken fountain of lava, from two
+hundred to seven hundred feet high and one thousand feet broad, burst
+out at the base of the mountain; and again in April, 1888, the same
+thing happened on a still grander scale. In this case four fiery
+fountains continued to play for several weeks, sometimes throwing
+the glowing lava to a height of one thousand feet in the air. Surely
+there can be no more wonderful or awful sight than this in the world.
+
+The volcanoes of Hawaii, the principal island in the Sandwich
+Islands, often send forth lava-streams covering an area of over
+one hundred square miles to a depth of one hundred feet or more;
+but they are discharged quite quietly, like water welling out of a
+spring. Repeated flows of this kind, however, have in the course of
+ages built up a great flat cone six miles high from the floor of the
+ocean, to form this lofty island, which is larger than Surrey; and
+it is calculated that the great volcanic mountain must contain enough
+material to cover the whole of the United States with a layer of rock
+fifty feet deep.
+
+But it is not only on the surface of the land that volcanic eruptions
+take place; for in some cases the outbreak of a submarine eruption
+has been witnessed, and it is highly probable that in past geological
+ages many large eruptions of this nature have taken place. In the
+year 1783, an eruption took place about thirty miles off the west
+coast of Iceland. An island was built up from which glowing vapour
+and smoke came forth; but in a year or less the waves had washed
+everything away, leaving only a submerged reef. The island of
+Santorin, in the Greek Archipelago, is a partly submerged volcano.
+
+But in some cases enormous outpourings of lava have taken place,
+not from volcanoes, but from openings of the ground here and there,
+and more usually from long fissures or cracks in the rocks lying at
+the surface. In many cases so much lava has quietly welled out in
+this way that the old features of the landscape have been completely
+buried up, and wide plains and plateaux formed over them. Sir A.
+Geikie says,--
+
+   "Some of the most remarkable examples of this type of volcanic
+   structure occur in western North America. Among these that of
+   the Snake River plain in Idaho may be briefly described.
+
+   "Surrounded on the north and east by lofty mountains, it
+   stretches westward as an apparently boundless desert of sand
+   and bare sheets of black basalt. A few streams descending into
+   the plain from the hills are soon swallowed up and lost. The
+   Snake River, however, flows across it, and has cut out of its
+   lava bed a series of picturesque gorges and rapids.
+
+   "The extent of country which has been flooded with basalt in
+   this and adjoining regions of Oregon and Washington has not
+   yet been accurately surveyed, but has been estimated to cover
+   a larger area than France and Great Britain combined. Looked
+   at from any point on its surface, one of these lava plains
+   appears as a vast level surface, like that of a lake bottom.
+   This uniformity has been produced either by the lava rolling
+   over a plain or lake bottom, or by the complete effacement of
+   an original, undulating contour of the ground under hundreds of
+   feet of lava in successive sheets. The lava, rolling up to the
+   base of the mountains, has followed the sinuosities of their
+   margin, as the waters of a lake follow its promontories and
+   bays."
+
+A few further examples of mud-lavas may be mentioned here. Cotopaxi,
+a great volcano in Ecuador, South America, with a height of 17,900
+feet, reaches so high into the atmosphere that the higher parts are
+capped with snow. In June, 1877, a great eruption took place, during
+which the melting of snow and ice gave rise to torrents of mud and
+water, which rushed down the steep sides of the mountain, so that
+large blocks of ice were hurried along. The villages around to a
+distance of about seventy miles were buried under a deposit of mud,
+mixed with blocks of lava, ashes, pieces of wood, etc.
+
+Sometimes a volcano discharges large quantities of mud directly
+from the crater. In this case the mud is not manufactured by the
+volcano itself, but finds its way through fissures and cracks from
+the bed of the neighbouring sea or rivers to the crater. Thus, in
+the year 1691, Imbaburu, one of the Andes of Quito, sent out floods
+of mud containing dead fish, the decay of which caused fever in the
+neighbourhood. In the same way the volcanoes of Java have often
+buried large tracts of fertile country under a covering of volcanic
+mud, thus causing great devastation.
+
+Vast quantities of dust are produced, as already explained, by the
+pounding action that takes place during an eruption, as portions
+of rock in falling down meet others that are being hurled into the
+air. Striking instances of this have occurred not far from Great
+Britain. Thus in the year 1783, during an eruption of Skaptar Jökull,
+so great was the amount of dust thus created that the atmosphere in
+Iceland was loaded with it for several months. Carried by winds, it
+even reached the northern parts of Scotland, and in Caithness so
+much of it fell that the crops were destroyed. This is remarkable,
+considering that the distance was six hundred miles. Even in Holland
+and Norway there are traces of this great shower of dust from the
+Icelandic volcano.
+
+During the fearful eruption of Tomboro, a volcano in the island of
+Sumbawa, in the Eastern Archipelago, in 1815, the abundance of ashes
+and dust ejected caused darkness at midday at Java, three hundred
+miles away, and even there the ground was covered to a depth of
+several inches. In Sumbawa itself the part of the island joining
+the mountain was entirely desolated, and all the houses destroyed,
+together with twelve thousand inhabitants. Trees and herbage were
+overwhelmed with pumice and volcanic dust. The floating pumice on the
+sea around formed a layer two feet, six inches thick, through which
+vessels forced their way with difficulty. From such facts as these
+it is clear that if in past ages volcanoes have been so powerfully
+active as they are now, we should expect to find lava-flows, dykes,
+and great deposits of volcanic ash deposited in water among the
+stratified rocks; and such is the case. Many large masses of rock
+familiar to the geologist, and often forming parts of existing
+mountains, are to be accounted for either as great lava-flows, or
+dykes that have forced their way in among the strata, or as extensive
+deposits of volcanic ash.
+
+But perhaps the reader would like to know what the inside of a
+volcanic crater is like during an eruption. Let us, then, take a peep
+into that fearful crater of Kilauea, in the Sandwich Islands. For
+this purpose we cannot do better than follow Miss Bird's admirable
+description of her adventurous expedition to this crater:--
+
+   "The abyss, which really is at a height of four thousand feet,
+   on the flank of Mauna Loa, has the appearance of a pit on
+   a rolling plain. But such a pit! It is quite nine miles in
+   circumference, and at its lowest area--which not long ago fell
+   about three hundred feet, just as ice on a pond falls when
+   the water below is withdrawn--covers six square miles. The
+   depth of the crater varies from eight hundred to one thousand
+   feet, according as the molten sea below is at flood or ebb.
+   Signs of volcanic activity are present more or less throughout
+   its whole depth, and for some distance round its margin, in
+   the form of steam-cracks, jets of sulphurous vapour, blowing
+   cones, accumulating deposits of acicular crystals of sulphur,
+   etc., and the pit itself is constantly rent and shaken by
+   earthquakes. Grand eruptions occurred with circumstances
+   of indescribable terror and dignity; but Kilauea does not
+   limit its activity to these outbursts, but has exhibited its
+   marvellous phenomena through all known time in a lake or lakes
+   on the southern part of the crater three miles from this side.
+
+   "This lake--the _Hale-mau-mau_, or 'House of Everlasting Fire,'
+   of the Hawaiian mythology, the abode of the dreaded goddess
+   Pele--is approachable with safety, except during an eruption.
+   The spectacle, however, varies almost daily; and at times the
+   level of the lava in the pit within a pit is so low, and the
+   suffocating gases are evolved in such enormous quantities, that
+   travellers are unable to see anything. There had been no news
+   from it for a week; and as nothing was to be seen but a very
+   faint bluish vapour hanging round its margin, the prospect was
+   not encouraging.... After more than an hour of very difficult
+   climbing, we reached the lowest level of the crater, pretty
+   nearly a mile across, presenting from above the appearance
+   of a sea at rest; but on crossing it, we found it to be an
+   expanse of waves and convolutions of ashy-coloured lava, with
+   huge cracks filled up with black iridescent rolls of lava only
+   a few weeks old. Parts of it are very rough and ridgy, jammed
+   together like field-ice, or compacted by rolls of lava, which
+   may have swelled up from beneath; but the largest part of the
+   area presents the appearance of huge coiled hawsers, the ropy
+   formation of the lava rendering the illusion almost perfect.
+   These are riven by deep cracks, which emit hot sulphurous
+   vapours....
+
+   "As we ascended, the flow became hotter under our feet, as well
+   as more porous and glistening. It was so hot that a shower of
+   rain hissed as it fell upon it. The crust became increasingly
+   insecure, and necessitated our walking in single file with the
+   guide in front, to test the security of the footing. I fell
+   through several times, and always into holes full of sulphurous
+   steam so malignantly acid that my strong dogskin gloves were
+   burned through as I raised myself on my hands.
+
+   "We had followed the lava-flow for thirty miles up to the
+   crater's brink, and now we had toiled over recent lava for
+   three hours, and by all calculation were close to the pit; yet
+   there was no smoke or sign of fire, and I felt sure that the
+   volcano had died out for once for our special disappointment....
+
+   "Suddenly, just above, and in front of us, gory drops were
+   tossed in the air, and springing forwards we stood on the brink
+   of _Hale-mau-mau_, which was about thirty-five feet below
+   us. I think we all screamed. I know we all wept; but we were
+   speechless, for a new glory and terror had been added to the
+   earth. It is the most unutterable of wonderful things. The
+   words of common speech are quite useless. It is unimaginable,
+   indescribable; a sight to remember for ever; a sight which
+   at once took possession of every faculty of sense and soul,
+   removing one altogether out of the range of ordinary life.
+   Here was the real 'bottomless pit,' 'the fire which is not
+   quenched,' 'the place of Hell,' 'the lake which burneth with
+   fire and brimstone,' 'the everlasting burnings,' 'the fiery
+   sea whose waves are never weary.'[26] There were groanings,
+   rumblings, and detonations, rushings, hissings, splashings,
+   and the crashing sound of breakers on the coast; but it was
+   the surging of fiery waves upon a fiery shore. But what can
+   I write? Such words as jets, fountains, waves, spray, convey
+   some idea of order and regularity, but here there was none.
+   The inner lake, while we stood there, formed a sort of crater
+   within itself; the whole lava sea rose about three feet; a
+   blowing cone about eight feet high was formed; it was never the
+   same two minutes together. And what we saw had no existence
+   a month ago, and probably will be changed in every essential
+   feature a month hence.... The prominent object was fire in
+   motion; but the surface of the double lake was continually
+   skimming over for a second or two with a cooled crust of a
+   lustrous grey-white, like frosted silver, broken by jagged
+   cracks of a bright rose-colour. The movement was nearly always
+   from the sides to the centre; but the movement of the centre
+   itself appeared independent, and always took a southerly
+   direction. Before each outburst of agitation there was much
+   hissing and throbbing, internal roaring, as of imprisoned
+   gases. Now it seemed furious, demoniacal, as if no power on
+   earth could bind it, then playful and sportive, then for a
+   second languid, but only because it was accumulating fresh
+   force.... Sometimes the whole lake ... took the form of mighty
+   waves, and surging heavily against the partial barrier with
+   a sound like the Pacific surf, lashed, tore, covered it, and
+   threw itself over it in clots of living fire. It was all
+   confusion, commotion, forces, terror, glory, majesty, mystery,
+   and even beauty. And the colour, 'eye hath not seen' it! Molten
+   metal hath not that crimson gleam, nor blood that living
+   light."[27]
+
+  [26] Perhaps these Scripture phrases were suggested long before
+  the Bible was written, by the sight of some crater in active
+  eruption.
+
+  [27] The Hawaiian Archipelago.
+
+Continued observation of volcanoes, together with evidence derived
+from history, teaches that there are different stages of volcanic
+action. There are three pretty well-marked phases. First, the state
+of permanent eruption; this is not a dangerous state, because the
+steam keeps escaping all the time: the safety-valve is at work, and
+all goes smoothly. The second state is one of moderate activity, with
+more or less violent eruptions at brief intervals; this is rather
+dangerous, because at times the safety-valve does not work.
+
+And thirdly, we have paroxysms of intense energy, alternating with
+long periods of repose sometimes lasting for centuries. These
+eruptions are extremely violent, and cause widespread destruction;
+the safety-valve has got jammed, and so the boiler bursts.
+
+No volcano has been so carefully watched for a long time as Vesuvius.
+Its history illustrates the phases we have just mentioned. The first
+recorded eruption is that of A. D. 79, a very severe one of the
+violent type, by which Herculaneum, Pompeii, and Stabiæ were buried.
+We have an interesting account by the younger Pliny. Before this
+great eruption took place, Vesuvius had been in a state of repose
+for eight hundred years, and if we may judge from the Greek and Roman
+writings, was not even suspected of being a volcano. Then followed
+an interval of rest until the reign of Severus, the second eruption
+taking place in the year 203. In the year 472, says Procopius, all
+Europe was covered more or less with volcanic ashes. Other eruptions
+followed at intervals, but there was complete repose for two
+centuries; that is, until the year 1306. In 1500 it was again active,
+then quiet again for one hundred and thirty years. In 1631 there took
+place another terrific outburst. After this many eruptions followed,
+and they have been frequent ever since. Vesuvius is therefore now in
+the second stage of moderate activity.
+
+But geologists can take a wider view than this. They can sum up the
+history of a volcanic region of the earth; and the result is somewhat
+as follows: Volcanoes, like living creatures, go through different
+periods or phases, corresponding roughly to youth, middle age, old
+age, and finally decay. The invasion of any particular area of the
+earth's surface by the volcanic forces is heralded by underground
+shocks, or earthquakes. A little later on cracks are formed, as
+indicated by the rise of saline and hot springs, and the issuing of
+carbonic acid and other gases at the surface of the earth. As the
+underground activity becomes greater, the temperature of the springs
+and emitted gases increases; and at last a visible rent is formed,
+exposing highly heated and glowing rock below. From the fissure thus
+formed, the gas and vapours imprisoned in the molten rocks escape
+with such violence as to disperse the latter in the form of pumice
+and volcanic ash, or to cause them to pour out as lava-streams.
+
+The action generally becomes confined to one or more points along the
+line of action (which is a line of fissures and cracks). In this way
+a chain of volcanoes is formed, which may become the seat of volcanic
+action for a long time.
+
+When the volcanic energies have become somewhat exhausted, so that
+they cannot raise up the lava and expel it from the volcanic crater,
+nor rend the sides of the volcano and cause minor cones to grow up
+on their flanks, small cones may be formed at a lower level in the
+plains around the great central chain. These likewise are fed from
+fissures.
+
+Later on, as the heated rock below cools down, the fissures are
+sealed up by lava that has become solid; and then the volcanoes
+fall, as it were, into the "sere and yellow leaf," and remain in a
+peaceful, quiet state befitting their old age.
+
+After this they begin to suffer from long exposure to the atmospheric
+influences of decay, and rain and rivers wash them away more or less
+completely.
+
+But still the presence of heated rocky matter at no great depth
+below is proved by the outbursts of gases and vapours, the forming
+of geysers and ordinary hot springs. Gradually, however, even these
+signs of heat below disappear; and the cycle of volcanic phases is at
+an end. Such a series of changes may require millions of years; but
+by the study of volcanoes in every stage of their growth and decline
+it is possible thus to sketch out an outline of their history.
+
+It must be confessed that in the present state of scientific
+knowledge no full and complete explanation of volcanic action is
+possible. Geologists and others are as yet but feeling their way
+cautiously towards the light which, perhaps before long, will
+illumine the dark recesses of this mysterious subject. Many theories
+and ideas have been put forward, but in the opinion of the writer the
+most promising explanation is one that may be briefly expressed as
+follows:
+
+There are below the crust of the earth large masses of highly
+heated rock that are _kept solid_ by the enormous pressure of the
+overlying rocks, or otherwise they would melt,--for it is a known
+fact that pressure tends to prevent the melting of a solid body. But
+when earth-movements taking place within the earth's crust--such
+as the upheaving of mountain-chains--take off some of the weight,
+the balance between internal heat and the pressure from above is no
+longer maintained; and so these highly heated rocks run off into
+the liquid state, and finding their way to the surface through the
+fissures mentioned above, give rise to volcanic action. There is
+much to be said in favour of this view. It rightly connects volcanic
+action with movements of upheaval, with mountain-chains and lines of
+weakness in the earth's crust.
+
+There is very good reason to believe that the earth was once in a
+highly heated state, and has been slowly cooling down for ages. The
+increase of temperature observed in penetrating mines tells us that
+it still retains below the surface some of its old heat. We need not
+therefore be surprised at the existence of heated masses of rock down
+below, or seek, as some have done, an entirely different source for
+the origin of volcanic heat than that which remains from the earth's
+once molten condition. It would take too long to state the reasons
+on which this idea of the former state of our planet is based, and
+moreover, it would bring us into the region of astronomy, with which
+we are not concerned at present.
+
+In various parts of Great Britain and Ireland we meet with old
+volcanic rocks,--lavas, intrusive dykes, and sheets of basalt, etc.,
+together with vast deposits of volcanic ash, which, sinking into
+the old neighbouring seas, became stratified, or arranged in layers
+like the ordinary sedimentary rocks. In some cases we see embedded
+in these layers the very "bombs" that were thrown out by the old
+volcanoes (see page 253). And besides these purely volcanic rocks, we
+often meet in these areas with great bosses of granite, which must
+have been in some way connected with the old volcanoes, and probably
+were in many cases the source from which much of the volcanic rock
+was derived. But more than this, in a few instances we have the site
+of the old volcano itself marked out by a kind of pipe, or "neck,"
+now filled with some of its volcanic débris in the shape of coarse,
+rounded fragments (see page 277).
+
+During a very ancient period, known to geologists as the Silurian
+Period, great lava-flows took place from volcanoes situated where
+North and South Wales and the Lake District now are; and by their
+eruptions a vast amount of volcanic ash was made, which fell into
+the sea and slowly sank to the bottom, so that the shell-fish living
+there were buried in the strata thus formed, and may now be seen in a
+fossilised condition.
+
+  [Illustration: Fig. 1. THE RANGES OF THE GREAT BASIN, WESTERN
+  STATES OF NORTH AMERICA, SHOWING A SERIES OF GREAT FRACTURES AND
+  TILTED MASSES OF ROCK.]
+
+  [Illustration: Fig. 2. SECTION THROUGH SNOWDON.]
+
+Thus Snowdon, Cader Idris, the Arans, Arenig Mountain, and others,
+are very largely made up of these ancient volcanic materials. The
+writer has picked up specimens of fossil shell-fish near the summit
+of Snowdon from a bed of fine volcanic ash that forms the summit.
+Fig. 2 represents a section through Snowdon, from which it will be
+seen that we have first a few sedimentary strata, _S_, then a great
+lava-flow, _L_; and that volcanic ashes accumulated on the top of
+this, of which _A A_ are patches still left. _B_ is an intrusive dyke
+of a basaltic rock that forced its way through afterwards. Again, in
+the Lake District there is a well-known volcanic series of stratified
+rocks of the same age, consisting mostly of lavas and ashes, the
+total thickness of which is about twelve thousand feet (known as the
+"Green Slates and Porphyries"), so that a large part of some of the
+mountains there have also been built up by volcanic action; but no
+traces of the old volcanoes remain.
+
+Going farther north we find abundant proof that volcanic action on
+a prodigious scale took place in Scotland during the very ancient
+period of the Old Red Sandstone, with which the name of Hugh Miller
+will always be associated. In Central Scotland we see lava-flows and
+strata formed of volcanic ash, with a thickness of more than six
+thousand feet, fragments of which, having escaped the destructive
+agents of denudation, now form important chains of hills, such
+as the Pentland, Ochil, and Sidlaw ranges. Nor was the volcanic
+action confined to this region. In the district of the Cheviot
+Hills similar volcanic rocks are to be seen. But here again the old
+volcanoes have long since been swept away, leaving us only portions
+of their outpourings buried in the hills.
+
+There can be no doubt that the present area of the Grampian Hills was
+once the site of a considerable number of volcanoes, only at a much
+higher level than their present surface, elevated though that is to
+the region of the clouds; but in this case subsequent denudation has
+been so enormous that the old mountain surface has been planed away
+until all we can now see is a series of separate patches of granite,
+that were once in a fused and highly heated state far below the
+surface, and formed part of the subterranean reservoirs from which
+the volcanoes derived their great supplies of lava and steam. It is
+indeed difficult to imagine the enormous amount of denudation which
+has taken place in the Highlands of Scotland, and to realise that the
+magnificent range of the Cairngorms, for instance, has been for ages
+worn down until now they are but a remnant of what they once were.
+
+In this region we see the once boiling and seething masses of
+rock which fed the old volcanoes, now no longer endowed with
+life-like power by the force of steam, but lying in deathlike cold
+and stiffness, with their beautiful crystals of mica and felspar
+sparkling in the sun. The volcanic fires have died out; but the
+traces of their work are unmistakable, among which we must not forget
+to reckon the beautiful minerals made by the action of heated water
+upon the surrounding rocks.
+
+The beautiful cairngorm stones are still sometimes found on the
+mountain from which they take their name, and in all volcanic regions
+minerals are plentiful.
+
+The well-known hill called Arthur's Seat, close to Edinburgh, marks
+the site of an old volcano. The "neck," or central opening, may be
+seen at the top of the hill, but choked up with volcanic rocks and
+débris. The crater has long since disappeared, but Salisbury Craigs
+and St. Leonard's Craigs are formed of a great sheet of basalt that
+intruded itself among the stratified rocks that had been formed
+there, and so belong really to a great intrusive dyke. In the Castle
+Rock we see the same basalt again.
+
+During a much later age, known as the Miocene Period (see chap. x.,
+p. 324), enormous outpourings of lava took place in Western Europe,
+covering hundreds of square miles. Of these the most important is
+that which occupies a large part of the northeast of Ireland, and
+extends in patches through the Inner Hebrides and the Faröe Islands
+into Iceland. These eruptive rocks, unlike those above referred to,
+must have poured out at the surface, and have taken the form of
+successive sheets, such as we now see in the terraced plateaux of
+Skye, Eigg, Canna, Muck, Mull, and Morven. These, then, are patches
+of what once formed a great plain of basalt. During later times
+this volcanic platform has been so greatly cut up by the agents of
+denudation that it has been reduced to mere scattered fragments;
+thousands of feet of basalt have been worn away from it; deep and
+wide valleys have been carved out of it; and in many cases it has
+been almost entirely stripped off from the wide areas it once
+covered. Where, as in the Isle of Eigg, the lava has been piled up
+in successive sheets, with some layers of volcanic ash between, the
+latter has been worn away rather faster than the hard layers of
+basalt, and each lava-flow is clearly marked by a terrace. These
+volcanic eruptions have thus had a great influence in moulding the
+scenery of this region. In Ireland the old basalts are well seen at
+the Giant's Causeway, and on the Scottish coast we see them again at
+the well-known Fingal's cave at Staffa. This island, like the others,
+is just a patch of the old lava-streams.
+
+Its curious six-sided columns illustrate a fact with regard to the
+subsequent cooling of lava-flows. Some internal forces, analogous to
+that which regulates the shapes of crystals, have caused it to crack
+along three sets of lines, so placed with regard to each other as to
+produce six-sided columns.
+
+In Ireland the basalts attain a thickness of nine hundred feet; in
+Mull they are about three thousand feet thick. It has been clearly
+proved that Mull is the site of one of the old volcanoes of this
+period, but very few others have as yet been detected. Perhaps the
+eruptions took place mainly from large fissures, instead of from
+volcanic cones, for it is known that the ground below the lava-sheets
+has been rent by earthquakes into innumerable fissures, into which
+the basalt was injected from below.
+
+In this way a vast number of "dykes" were formed. These have been
+traced by hundreds eastwards from this region across Scotland,
+and even the north of England. In this case the molten rock was
+struggling to get through the overlying rocks and escape at the
+surface; but apparently it did not succeed in so doing, for we do not
+find lava-flows to the east and south. These basalt dykes are found
+as far south as Yorkshire, and can be traced over an area of one
+hundred thousand square miles.
+
+It is thus evident that in the Miocene Period a great and extensive
+mass of molten basalt was underlying a large part of the British
+Isles, and probably the weight of the thick rocks overlying it was
+sufficient to prevent its escape to the surface. If it had succeeded
+in so escaping and overflowing, how different the scenery of much of
+Scotland and Northern England might have been!
+
+  [Illustration: COLUMNAR BASALT AT CLAMSHELL CAVE, STAFFA. FROM A
+  PHOTOGRAPH BY J. VALENTINE.]
+
+
+
+
+CHAPTER IX.
+
+MOUNTAIN ARCHITECTURE.
+
+    The splendour falls on castle walls
+      And snowy summits old in story;
+    The long light shakes across the lakes,
+      And the wild cataract leaps in glory.
+    Blow, bugle, blow, set the wild echoes flying;
+    Blow, bugle; answer, echoes, dying, dying, dying.
+
+    TENNYSON.
+
+
+The dying splendours of the sun slowly sinking and entering the
+"gates of the West" may well serve as a fitting emblem of the
+mountains in their beautiful old age, awaiting in silent and calm
+dignity the time when they also must be brought low, and sink in the
+waters of the ocean, as the sun appears daily to do. Yes, they too
+have their day. They too had their rising, when mighty forces brought
+them up out of their watery bed. Many of them have passed their
+hey-day of youth, and their midday; while others, far advanced in old
+age, are nearing the end of their course.
+
+But as the sun rises once more over eastern seas to begin another
+day, so will the substance of the mountains be again heaved up after
+a long, long rest under the sea, and here and there will rise up from
+the plains to form the lofty mountain-ranges of a distant future.
+
+Everywhere we read the same story, the same circle of changes. The
+Alpine peak that proudly rears its head to the clouds must surely
+be brought low, and finally come back to the same ocean from which
+those clouds arose. It is in this way that the balance between land
+and water is preserved. In passing through such a great circle of
+changes, the mountains assume various forms and shapes which are
+determined by:--
+
+   1. Their different ages and states of decay.
+
+   2. The different kinds of rocks of which they are composed, and
+   especially by their "joints," or natural divisions.
+
+   3. The different positions into which these rocky layers have
+   been squeezed, pushed, and crumpled by those stupendous forces
+   of upheaval of which we spoke in chapter vi.
+
+Let us therefore glance at some of these external forms, and then
+look at the internal structure of mountains.
+
+In so doing we shall find that we have yet a good deal more to learn
+about mountains and how they were made; and also we shall then be in
+a better position to realise not only how very much denudation they
+have suffered, but also how greatly they have been disturbed since
+their rocks were first made.
+
+Every one who knows mountains must have observed how some are smooth
+and rounded, others sharp and jagged, with peaks and pinnacles
+standing out clearly against the sky; some square and massive, with
+steep walls forming precipices; others again spread out widely at
+their base, but the sloping sides end in a sharp point at the top,
+giving to the mountain the appearance of a cone. Their diversities of
+shape are so endless that we cannot attempt to describe them all.
+
+First, with regard to the general features of mountains. Looked
+at broadly, a mountain-range is not a mere line of hills or
+mountains rising straight up from a plain on each side, such as
+school-boys often draw in their maps; very far from it. Take the
+Rocky Mountains, for instance. "It has been truly said of the Rocky
+Mountains that the word 'range' does not express it at all. It is a
+whole country populous with mountains. It is as if an ocean of molten
+granite had been caught by instant petrifaction when its billows were
+rolling heaven high."[28]
+
+  [28] "The Crest of the Continent," by Ernest Ingersoll, Chicago,
+  1885.
+
+It has often been observed by mountain climbers that when they get
+to the top of a high mountain, and take a bird's-eye view of the
+country, all the mountain-tops seem to reach to about the same
+height, so that a line joining them would be almost level. For this
+reason, perhaps, writers so often compare them to the waves of an
+ocean. This feature is very conspicuous in the case of the Scotch
+Highlands.
+
+Sir A. Geikie has well described what he saw from the top of Ben
+Nevis:--
+
+   "Much has been said and written about the wild, tumbled sea of
+   the Highland Hills. But as he sits on his high perch, does it
+   not strike the observer that there is after all a wonderful
+   orderliness, and even monotony, in the waves of that wide
+   sea? And when he has followed their undulations from north to
+   south, all round the horizon, does it not seem to him that
+   these mountain-tops and ridges tend somehow to rise to a
+   general level; that, in short, there is not only on the great
+   scale a marked similarity of contour about them, but a still
+   more definite uniformity of average height? To many who have
+   contented themselves with the bottom of the glen, and have
+   looked with awe at the array of peaks and crags overhead, this
+   statement will doubtless appear incredible. But let any one get
+   fairly up to the summits and look along them, and he will not
+   fail to see that the statement is nevertheless true. From the
+   top of Ben Nevis this feature is impressively seen. Along the
+   sky-line, the wide sweep of summits undulates up to a common
+   level, varied here by a cone and there by the line of some
+   strath or glen, but yet wonderfully persistent round the whole
+   panorama. If, as sometimes happens in these airy regions, a
+   bank of cloud with a level under-surface should descend upon
+   the mountains, it will be seen to touch summit after summit,
+   the long line of the cloud defining, like a great parallel
+   ruler, the long level line of the ridges below. I have seen
+   this feature brought out with picturesque vividness over the
+   mountains of Knoydart and Glen Garry. Wreaths of filmy mist had
+   been hovering in the upper air during the forenoon. Towards
+   evening, under the influence of a cool breeze from the north,
+   they gathered together into one long band that stretched for
+   several miles straight as the sky-line of the distant sea,
+   touching merely the higher summits and giving a horizon by
+   which the general uniformity of level among the hills could be
+   signally tested. Once or twice in a season one may be fortunate
+   enough to get on the mountains above such a stratum of mist,
+   which then seems to fill up the irregularities of the general
+   platform of hill-tops, and to stretch out as a white phantom
+   sea, from which the highest eminences rise up as little islets
+   into the clear air of the morning.... Still more striking
+   is the example furnished by the great central mass of the
+   Grampians, comprising the Cairngorm Mountains and the great
+   corries and precipices round the head of the Dee. This tract
+   of rugged ground, when looked at from a distance, is found to
+   present the character of a high, undulating plateau."[29]
+
+  [29] Scenery of Scotland page 130, new edition.
+
+This long level line of the Highland mountain-tops may be seen very
+well from the lower country outside; for example, from the isles of
+Skye and Eigg, where one may see the panorama between the heights of
+Applecross and the Point of Ardnamurchan showing very clearly the
+traces of the old table-land.
+
+How are we to explain this curious fact, so opposed to our first
+impressions of a mountain region? It is quite clear that the
+old plateau thus marked out cannot be caused by the arrangement
+or position of the rocks of which the Highlands are composed. If
+these rocks were found to be lying pretty evenly in flat layers,
+or strata, undisturbed by great earth-movements, we could readily
+understand that they would form a plateau. But the reverse is the
+case: the rocks are everywhere thrown into folds, and frequently
+greatly displaced by "faults;" yet these important geological
+features have little or no connection with the external aspect of the
+country. It is therefore useless to look to internal structure for
+an explanation. We must look outside, and consider what has been for
+ages and ages taking place here.
+
+As already pointed out, an enormous amount of solid rock has been
+removed from this region--thousands and thousands of feet. It was
+long ago planed down by the action of water, so that a table-land
+once existed of which the tops of the present mountains are isolated
+fragments. No other conclusion is possible. To the geologist every
+hill and valley throughout the whole length and breadth of the
+Highlands bears striking testimony to this enormous erosion. The
+explanation we are seeking may therefore be summed up in one word,
+"denudation." The valleys that now intersect the table-land have been
+carved out of it. If we could in imagination put back again onto
+the present surface what has been removed, we should have a mental
+picture of the Highlands as a wide, undulating table-land; and this
+rolling plain would suggest the bottom of the sea. The long flat
+surfaces of the Highland ridges, cut across the edges of inclined
+or even upright strata, are the fragments of a former base-line of
+erosion; that is, they represent the general submarine level to which
+the Highlands were reduced after exposure to the action of "rain and
+rivers," and finally of the sea. As the sea gradually spread over it,
+it planed down everything that had not been previously worn away, and
+so reduced the whole surface to one general level like the sea-bed of
+the present day. But it is not necessary to suppose that the whole
+region was under water at the same time, and it is probable that
+there were separate inland seas or lakes. In these the rocks of the
+Old Red Sandstone were formed; and they in their turn have suffered
+so much denudation that only patches and long strips of them are left
+on the borders of the Highlands.
+
+Before we speak of individual mountains and their shapes, it is
+important to bear in mind another fact about mountain-chains;
+namely, that they are very low in proportion to their breadth and
+length. The great heights reached by some mountains produce such a
+powerful impression on our senses that we hardly realise how very
+insignificant they really are. It is only by drawing them on a true
+scale that we can realise this. The surface of the earth is so vast
+that even the highest mountains are in proportion but as the little
+roughnesses on the skin of an orange. Fig. 2 (see chap, vii., p. 236)
+represents a section through the Highlands, drawn on the same scale
+for height as for length.
+
+
+What has been said about the Highland plateau applies equally well
+to many other mountain-ranges. Mr. Ruskin observed something rather
+similar in the Alps. He says,--
+
+   "The longer I stayed in the Alps, and the more closely I
+   examined them, the more I was struck by the one broad fact of
+   there being a vast Alpine plateau, or mass of elevated land,
+   upon which nearly all the highest peaks stood like children set
+   upon a table, removed, in most cases, far back from the edge
+   of the plateau, as if for fear of their falling; ... and for
+   the most part the great peaks are not allowed to come to the
+   edge of it, but remain like the keeps of castles, withdrawn,
+   surrounded league beyond league by comparatively level fields
+   of mountains, over which the lapping sheets of glaciers writhe
+   and flow, foaming about the feet of the dark central crests
+   like the surf of an enormous sea-breaker hurled over a rounded
+   rock and islanding some fragment of it in the midst. And the
+   result of this arrangement is a kind of division of the whole
+   of Switzerland into an upper and a lower mountain world,--the
+   lower world consisting of rich valleys, bordered by steep but
+   easily accessible, wooded banks of mountain, more or less
+   divided by ravines, through which glimpses are caught of the
+   higher Alps; the upper world, reached after the first steep
+   banks of three thousand or four thousand feet in height have
+   been surmounted, consisting of comparatively level but most
+   desolate tracts of moor and rock, half covered by glacier, and
+   stretching to the feet of the true pinnacles of the chain."
+
+He then points out the wisdom of this arrangement, and shows how it
+protects the inhabitants from falling blocks and avalanches; and
+moreover, the masses of snow, if cast down at once into the warmer
+air, would melt too fast and cause furious inundations.
+
+All the various kinds of rocks are differently affected by the
+atmospheric influences of decay, and so present different external
+appearances and shapes, so that after a little experience the
+geologist can recognize the presence of certain rocks by the kind
+of scenery they produce; and this knowledge is often of great use
+in helping him to unravel the geological structure of a difficult
+region. Thus granite, crystalline schists, slates, sandstones, and
+limestones, all "weather" in their own ways, and moreover split up
+differently, because their joints and other natural lines of division
+run in different ways.
+
+Thus granite is jointed very regularly, some of the joints running
+straight down and others running horizontally, so that the rain and
+atmosphere seize on these lines and widen them very considerably; and
+thus the granite is weathered out either in tall upright columns,
+like those seen at Land's End, or else into great square-shaped
+blocks with their corners rounded off, presenting the appearance
+of a number of knapsacks lying one over the other. In this way
+we can account for the well-known "Tors" of Devonshire, and the
+"Rocking Stones." Granite weathers rapidly along its joints, and
+its surfaces crumble away more rapidly than might be expected,
+considering how hard a rock it is; but the felspar which is its chief
+mineral constituent is readily decomposed by rain water, which acts
+chemically upon it. The deposits of China clay in Devonshire are
+the result of the decomposition and washing away of the granite of
+Dartmoor.
+
+Granite mountains are generally rounded and "bossy," breaking now
+and then into cliffs, the faces of which are riven by huge joints,
+and present a very different appearance from those composed of
+crystalline schists with their sharp crests and peaks. Ben Nevis and
+the Cairngorms are partly composed of granite.
+
+Gneiss is a rock composed of the same minerals as granite; namely,
+mica, quartz, and felspar. And yet mountains composed of this rock
+have quite a different aspect, and sometimes, as in the Alps, produce
+very sharp and jagged pinnacles. The reason of this is that gneiss
+splits in a different way from granite, because its minerals are
+arranged in layers, and so it is more like a crystalline schist.
+
+Mica-schist is another rock very abundant in mountain regions. This
+rock is composed of quartz and mica arranged in wavy layers. The
+mica, which is very conspicuous, lies in thin plates, sometimes
+so dovetailed into each other as to form long continuous layers
+separating it from those of the quartz; and it readily splits along
+the layers of mica. This mineral is easily recognised by its bright,
+shiny surface. There are, however, two varieties,--one of a light
+colour and the other black.
+
+Mica-schist and gneiss are often found in the same region, and are
+the materials of which most of the highest peaks in Europe are
+composed. We find them abounding in the district of Mont Blanc; and
+all the monarch's attendant _aiguilles_, with the splintered ridges
+enclosing the great snowfields in the heart of the chain, consist
+mostly of these two rocks. The Matterhorn, Weisshorn, Monte Viso, the
+Grand Paradis, the Aiguille Verte and Aiguille du Dru are examples of
+the wonderful forms produced by the breaking up and decay of these
+two rocks.
+
+The different varieties of slate split in a very marked way. Slates
+are often associated with the schists, and exert their influence in
+modifying the scenery.
+
+Limestone ranges, though less striking in the outlines of their
+crests than those composed of slates and crystalline schists, and not
+reaching to such heights, are nevertheless not at all inferior in the
+grandeur of their cliffs, which frequently extend for miles along the
+side of a valley in vast terraces, whose precipitous walls are often
+absolutely inaccessible. The beauty of limestone mountains is often
+enhanced by the rich pastures and forests which clothe their lower
+slopes. The dolomitic limestone of the Italian Tyrol, being gashed by
+enormous vertical joints and at the same time having been formed in
+rather thin layers which break up into small blocks, produces some
+very striking scenery. But wild as these mountainous ridges may be,
+their forms can never be confounded with those of the crystalline
+schists; for however sharp their pinnacles may appear at first sight,
+careful examination will always show that their outline is that
+of ruined masonry, suggesting crumbling battlements and tottering
+turrets, and not the curving, flame-like crests and splintered peaks
+of the crystalline schists.[30]
+
+  [30] Bonney.
+
+It has already been explained that all sedimentary rocks have been
+formed under water in layers or strata, and it must be obvious
+that the stratification of such rocks has an important influence
+on scenery; and very much depends on whether the strata have been
+left undisturbed, with perhaps just a slight slope, or whether they
+have been folded and crumpled; for the position of the strata, or
+"bedding," as it is called,--whether flat, inclined, vertical, or
+contorted,--largely determines the nature of the surface. Undoubtedly
+the most characteristic scenery formed by stratified rocks is to be
+seen in those places where the "bedding" is horizontal, or nearly so,
+and the strata are massive. A mountain constructed of such materials
+appears as a colossal pyramid, the level lines of stratification
+looking like great courses of masonry. The joints that cut across the
+strata allow it to be cleft into great blocks and deep chasms; so
+that, as in the case of the dolomitic limestone above mentioned, we
+find a resemblance to ruined buildings.
+
+We cannot find a better example of this in our own country than the
+mountains of sandstone and conglomerate (of the Cambrian age) that
+here and there lie on the great platform of old gneiss in the west of
+Sutherland and Ross. Sir A. Geikie says,--
+
+   "The bleak, bare gneiss, with its monotonous undulations,
+   tarns, and bogs, is surmounted by groups of cones, which for
+   individuality of form and independence of position better
+   deserve to be called mountains than most of the eminences to
+   which that name is given in Scotland. These huge pyramids,
+   rising to heights of between two thousand and four thousand
+   feet, consist of dark red strata, so little inclined that
+   their edges can be traced by the eye in long, level bars on
+   the steeper hillsides and precipices, like lines of masonry.
+   Here and there the hand of time has rent them into deep rifts,
+   from which long 'screes' (slopes of loose stones) descend into
+   the plains below, as stones are detached from the shivered
+   walls of an ancient battlement. Down their sides, which have in
+   places the steepness of a bastion, vegetation finds but scanty
+   room along the projecting ledges of the sandstone beds, where
+   the heath and grass and wildflowers cluster over the rock in
+   straggling lines and tufts of green; and yet, though nearly as
+   bare as the gneiss below them, these lofty mountains are far
+   from presenting the same aspect of barrenness. The prevailing
+   colour of their component strata gives them a warm red hue,
+   which even at noon contrasts strongly with the grey of the
+   platform of older rock.... These huge isolated cones are among
+   the most striking memorials of denudation anywhere to be seen
+   in the British Isles. Quinag, Canisp, Suilven, Coulmore, and
+   the hills of Coygoch, Dundonald, Loch Maree, and Torridon are
+   merely detached patches of a formation not less than seven
+   thousand or eight thousand feet thick, which once spread
+   over the northwest of Scotland. The spaces between them were
+   once occupied by the same dull red sandstone; the horizontal
+   stratification of one hill, indeed, is plainly continuous with
+   that of the others, though deep and wide valleys, or miles
+   of low moorland, may now lie between. While the valleys have
+   been worn down through the sandstone, these strange pyramidal
+   mountains that form so singular a feature in the landscapes of
+   the northwest highlands have been left standing, like lonely
+   sea-stacks, as monuments of long ages of waste."[31]
+
+  [31] Scenery of Scotland, page 201, new edition.
+
+Again, the vast table-lands of the Colorado region illustrate on
+a truly magnificent scale, to which there is no parallel in the
+Old World, the effects of atmospheric erosion on undisturbed and
+nearly level strata. Here we find valleys and river gorges deeper
+and longer than any others in the world; great winding lines of
+escarpment, like ranges of sea cliffs; terraced slopes rising at
+various levels; huge buttresses and solitary monuments, standing like
+islands out of the plains; and lastly, great mountain masses carved
+out into the most striking and picturesque shapes, yet with their
+lines of "bedding" clearly marked out.
+
+On the other hand, where, as is almost always the case in
+mountain-ranges, the stratified rocks have been folded, crumpled,
+twisted, and fractured by great "faults," we find a very different
+result. In these cases the rocks have generally been very much
+altered by the action of heat. For here we find crystalline schists,
+gneiss, granite, and other rocks in the formation of which heat has
+played an important part; and very often the igneous rocks have
+forced their way through those of sedimentary origin and altered them
+into what are called metamorphic rocks (see chapter v., page 156).
+Thus they have lost much of their original character and structure.
+
+The repeated uplifts and subsidences of the earth's crust, by which
+the continents of the world have been raised up out of the sea
+to form dry land, have, broadly speaking, thrown the rocky strata
+into a series of wave-like undulations. In some extensive regions
+these undulations are so broad and low that the curvature is quite
+imperceptible, and the strata appear to lie in horizontal layers, or
+to slope very slightly in a certain direction. This is, in a general
+way, the position of the strata of which plains and plateaux are
+composed.
+
+But in the longer and comparatively narrow mountain regions that
+traverse each of the great continents, forming, as it were, backbones
+to them, the undulations are very much more frequent, narrower, and
+higher. Sometimes the rocks have been thrown into huge open waves, or
+the folds are closely crowded together, so that the strata stand on
+their ends, or are even completely overturned, and thus their proper
+order of succession is reversed, and the older ones actually lie on
+the top of the newer ones.
+
+As we approach a great mountain-chain we observe many minor ridges
+and smaller chains running roughly parallel with it, and, as it
+were, foreshadowing the great folds met with in the centre of the
+chain and among its highest peaks. These small folds become sharper
+and closer the nearer we get to the main chain, and evidently were
+formed by the same movements that uplifted the higher ranges beyond;
+but the force was not so great. Thus we find the great Alpine chain
+flanked to the north by the smaller ranges of the Jura Mountains; and
+on the south, side of the Himalayas we find similar smaller ranges of
+hills.
+
+Ruskin thus describes his impression of the Jura ranges, which he
+very aptly compares with a swell on the sea far away from a storm,
+the storm being represented by the wild sea of Alpine mountains:--
+
+   "Among the hours of his life to which the writer looks back
+   with peculiar gratitude, as having been marked with more
+   than ordinary fulness of joy or clearness of teaching, is
+   one passed, now some years ago, near time of sunset, among
+   the masses of pine forest which skirt the course of the Ain,
+   above the village of Champagnole, in the Jura. It is a spot
+   which has all the solemnity, with none of the savageness, of
+   the Alps; where there is a sense of a great power beginning
+   to be manifested in the earth, and of a deep and majestic
+   concord in the rise of the long low lines of piny hills,--the
+   first utterance of those mighty mountain symphonies, soon to
+   be more loudly lifted and wildly broken along the battlements
+   of the Alps. But their strength is as yet restrained; and the
+   far-reaching ridges of pastoral mountain succeed each other,
+   like the long and sighing swell which moves over quiet waters
+   from some far-off stormy sea.
+
+   "And there is a deep tenderness pervading that vast monotony.
+   The destructive forces and the stern expression of the central
+   ranges are alike withdrawn. No frost-ploughed, dust-encumbered
+   paths of ancient glacier fret the soft Jura pastures; no
+   splintered heaps of ruin break the fair ranks of her forests;
+   no pale, defiled, or furious rivers rend their rude and
+   changeful ways among her rocks. Patiently, eddy by eddy, the
+   clear green streams wind along their well-known beds; and under
+   the dark quietness of the undisturbed pines there spring up,
+   year by year, such company of joyful flowers as I know not the
+   like among all the blessings of the earth."
+
+Long faults, or fractures, where the strata have been first bent
+and then broken, and afterwards have been forced up or have slid
+down hundreds or even thousands of feet, are very numerous in
+mountain-ranges; and by suddenly bringing quite a different set of
+rocks to the surface, these faults cause considerable difficulty to
+the geologist, as he goes over the ground and endeavours to trace the
+positions of the different rocks.
+
+In these vast folds it sometimes happens that portions of older (and
+lower) strata are caught up and so embedded among those of newer
+rocks. It will therefore be readily perceived that to unravel the
+geological structure of a great mountain-chain is no easy task.
+We need not then be surprised if in some cases the arrangement of
+the rocks of mountains is not thoroughly understood. The wonder
+is, when we think of the numerous difficulties which the geologist
+encounters,--the arduous ascents, the precipices, glaciers,
+snowfields obscuring the rocks from his view, the overlying soil
+of the lower parts, and the steep crests and dangerous ridges that
+separate the snowfields,--that so much has already been discovered in
+this difficult branch of geology.
+
+However, the general arrangement of the rocks of which many
+mountain-chains are composed has been satisfactorily made out in not
+a few cases. Let us look into some of these and see what has been
+discovered.
+
+You will remember the structure of the Weald, described in chap.
+vii., pp. 235-238, and how we showed that a great low arch of chalk
+strata has been entirely removed over that area, so that at the
+present time only its ends are seen forming the escarpments of the
+North and South Downs. This area, then, is now a great open valley,
+or rather a gently undulating plain enclosed by low chalk hills. Now,
+an arch of this kind is called an "anticline," and it might have been
+expected that it would have remained more or less unbroken to the
+present day. Why, then, has it suffered destruction?
+
+In the first place, chalk is a soft rock, and one that rain water can
+dissolve; but more than that, its arch-like structure was against it,
+and its chance of preservation was decidedly small. In architecture
+the arch is the most firm and stable structure that can be made; but
+not so with strata, and this is the reason. Such an arch was not made
+of separate blocks, closely fitting and firmly cemented together;
+on the contrary, the arch was stretched and heaved up from below.
+It therefore must have been more or less cracked up; for rocks are
+apt to split when bent, although when deeply buried under a great
+thickness of overlying rocks, they will bend very considerably
+without snapping. But this was not the case here. And so the forces
+of denudation set to work upon an already somewhat broken mass of
+rock. Try to picture to yourself this old low arch of chalk as it was
+when it first appeared as dry land. Probably some of it had already
+been planed away by the waves of the sea, and what was left was by
+no means well calculated to withstand the action of the agents of
+denudation. If you look back to the figure, you will see the dotted
+lines showing the former outline of this anticline, or arch, and you
+perceive at once that the strata must have been sloping outwards away
+from the middle. Now, this one fact greatly influenced its fate, for
+an anticline cannot be regarded as a strong or stable arrangement
+of strata. It is easy to see why; suppose a little portion were cut
+away on one side at its base by some stream. It is clear that a kind
+of overhanging cliff would be left, and blocks of chalk would sooner
+or later come rolling down into the valley of the little stream.
+When these had fallen, they would leave an inclined plane down which
+others would follow; and this would continue to take place until the
+top of the arch was reached. The same reasoning applies to the other
+side. It is very seldom that arches, or anticlines, can last for a
+long time. The outward slope of the strata and their broken condition
+are against them.
+
+But when the rocks dip _inwards_, to form a kind of trough or basin,
+it is just the opposite. Such basins are known as "synclines;" and
+a structure of this kind can be shown to be much more stable and
+permanent than an anticline. The strata, instead of being stretched
+out and cracked open, have been squeezed together.
+
+It is very important to bear this in mind, and to remember how
+differently anticlines and synclines are affected; for this simple
+rule is illustrated over and over again in mountain-ranges:--
+
+   Anticlines, being unstable, are worn away until they become
+   valleys.
+
+   Synclines, being stable, are left and frequently form mountains.
+
+Now look at the section through the Appalachian chain (see Fig.
+1), and you will see that each hill is a syncline, and the valleys
+between them are anticlines. This happens so frequently that almost
+every range of mountains furnishes examples; but as every rule has
+its exceptions, so this one has, and we may find an example in the
+case of the Jura Mountains outside the Alps.
+
+It will be seen from the section that the ridges are formed by
+anticlines, and the valleys by synclines. But on looking a little
+more closely, we see that the tops of the former have suffered a
+considerable amount of erosion (as indicated by the dotted lines).
+Now, the reason why they have not been completely worn down into
+valleys is that these rocks were once covered by others overlying
+them, so that this outer covering of rocks had first to be removed
+before they could be attacked by rain and rivers. These wave-like
+ridges of the Jura are being slowly worn down; and the time must
+come when they will be carved out into valleys, while the synclines
+between them will stand out as hills. It is simply a question of
+time. But many mountain-chains have a far more complicated structure
+than that of the Appalachians, and consist of violently crumpled and
+folded strata (see section of Mont Blanc, Fig. 3).
+
+  [Illustration: SECTIONS OF MOUNTAIN-RANGES, SHOWING THEIR
+  STRUCTURE AND THE AMOUNT OF ROCK WORN AWAY.]
+
+It might naturally be asked how such sections are made, considering
+that we cannot cut through mountains in order to find out their
+structure; but Nature cuts them up for us, gashing their sides with
+ravines and valleys carved out by streams and rivers, and in steep
+cliffs and precipices we find great natural sections that serve our
+purpose almost equally well. Sometimes, however, we get considerable
+help from quarries and railway-cuttings.
+
+Take, for example, one of the synclinal folds in the Appalachian
+chain. Its structure is ascertained somewhat as follows. Suppose you
+began to ascend the hill, armed with a good map, a pocket-compass, a
+clinometer,--a little instrument for measuring the angles at which
+strata dip or slope,--and with a bag on your back for specimens
+of rocks and fossils. At the base of the hill you might notice at
+starting a certain layer of rock--say a limestone--exposed by the
+side of the stream. It will be so many feet thick, and will contain
+such-and-such fossils, by means of which you can identify it; and
+it will dip into the interior of the hill at a certain angle, as
+measured by the clinometer. As you rise higher, this rock may be
+succeeded by sandstone of a certain thickness, and likewise dipping
+into the hill; and so with the other rocks that follow, until you
+reach the summit.
+
+By the time you have reached the top of the hill, you know the nature
+of all the rocks up that side, and the way they dip; and all your
+observations are carefully recorded in a notebook. Then you begin
+to descend on the other side, and in so doing you find the same set
+of rocks coming out at the surface all in the same order; only this
+order is now reversed, because you are following them downwards
+instead of upwards. Of course they are hidden in many places by soil
+and loose stones; but that does not matter, because at other places
+they are exposed to view, especially along ravines, carved out of
+the mountain-side. Also rocks "weather" so differently that they can
+often be distinguished even at a distance.
+
+In this kind of way you can find out the structure of a mountain,
+and draw a section of it when you get home, by following out and
+completing the curves of the strata as indicated at or near the
+surface; and you find they fit in nicely together.
+
+Fig. 3 (see page 307) represents what is believed to be the general
+arrangement of the rocks of Mont Blanc. The section is greatly
+simplified, because many minor folds and all the faults, or
+dislocations, are omitted. Now, in this case we have an example of
+what is known as the "fan-structure." It will be seen at once that
+the folds have been considerably squeezed together; and the big fold
+in the centre indicated by dotted lines has been so much compressed
+in the lower part--that is, in what is now Mont Blanc--that its sides
+were brought near to each other until they actually sloped inwards
+instead of outwards.
+
+You may easily imitate this structure by taking a sheet of paper,
+laying it on the table, and then, putting one hand on each side of
+it, cause it to rise up in a central fold by pressing your hands
+towards each other. Notice carefully what happens. First, you get a
+low arch, or anticline, like that of the Weald. Then as you press it
+more, the upward fold becomes sharper and narrower; then continue
+pressing it, and you will find the fold bulging out at the top, but
+narrowing in below until you get this fan-structure.
+
+This is just what has happened in the case of the Alps. A tremendous
+lateral pressure applied to the rocks heaved them up and down
+into great and small folds, and in some places, as in Mont Blanc,
+fan-structure was produced. Imagine the top of the fan removed, and
+you get what looks like a syncline, but is really the lower part of a
+very much compressed anticline.
+
+Now, it is believed that all mountain-ranges have been enormously
+squeezed by lateral pressure; and the little experiment with the
+sheet of paper furnishes a good illustration of what has happened. A
+table-cloth lying on a smooth table will serve equally well. You can
+easily push it into a series of folds; notice how they come nearer
+as you continue pushing. You see also that in this way you get long
+narrow ridges with valleys between. These represent the original
+anticlines and synclines of mountain-ranges, which in course of time
+are carved out, as explained above, until the synclines become hills
+and the anticlines valleys.
+
+Every mountain-chain must originally have had long ridges like these,
+which in some cases determined the original directions of the streams
+and valleys; and it is easy to see now why mountain-chains are long
+and narrow, why their strata have been so greatly folded, and why
+we get in every mountain-chain long ranges of hills roughly parallel
+with each other (see chapter vi., pages 177-178).
+
+The reason why granite, gneiss, and crystalline schists are
+frequently found in the central and highest peaks of mountain-ranges
+is that we have the oldest and lowest rocks exposed to the surface,
+on account of the enormous amount of denudation that has taken place.
+There may be great masses of granite underlying all mountain-chains;
+but it is only exposed to view when a very great deal of overlying
+rock has been removed.
+
+It was thought at one time that granite was the oldest of all rocks,
+and that mountain-chains had been upheaved by masses of granite
+pushing them up from below; but we know now that both these ideas
+are mistaken. Some granites are certainly old geologically, but
+others are of later date; and it is certain that granite was not the
+upheaving agent, but more likely it followed the overlying rocks as
+they were heaved up by lateral pressure, because the upward bending
+of the rocks would tend to relieve the enormous pressure down below,
+and so the granite would rise up.
+
+  [Illustration: MONT BLANC. SNOWFIELDS, GLACIERS. AND STREAMS.]
+
+We now pass on to a very different example, where mountains are the
+result of huge fractures and displacements; namely, the numerous
+and nearly parallel ranges of the Great Basin, of Western Arizona,
+and Northern Mexico. The region between the Sierra Nevada and the
+Wahsatch Mountains, extending from Idaho to Mexico, is composed
+of very gently folded rocks deeply buried in places by extensive
+outflows of lava.
+
+Now, in this case the earth-movements caused great cracks, or splits,
+doubtless attended by fearful earthquakes. We find here a series of
+nearly parallel fractures, hundreds of miles long, and fifteen to
+thirty miles apart. These traverse the entire region, dividing the
+rocks into long narrow blocks. There is evidence to show that the
+whole region was once much more elevated than it is now, and has
+subsided thousands of feet. During the subsidence along these lines
+of fracture, or faults, the blocks were tilted sideways; and the
+uptilted blocks, carved by denudation, form the isolated ranges of
+this very interesting region (see illustration, chap. viii., p. 273,
+Fig. 1). The faults are indicated by arrows pointing downwards; and
+the dotted lines indicate the erosion of the uptilted blocks.
+
+But this must be regarded as a very exceptional case, for we do not
+know of any other mountain-range formed quite in the same way. Why
+the strata, although only slightly bent, should have snapped so
+violently in this case, while in other mountain-ranges they have
+suffered much more bending without so much fracture and displacement,
+we cannot tell, but can only suggest that possibly it was because
+they were not buried up under an enormous thickness of overlying
+rocks, which would exert an enormous downward pressure, and so tend
+to prevent fracturing.
+
+There are many other deeply interesting questions with regard to the
+upheaval of mountains which at present cannot be answered.
+
+We have already learned to alter our preconceived ideas about the
+stability and immovable nature of the earth's crust, and have seen
+that it is in reality most unstable, and is undergoing continual
+movements, both great and small. But here we have an equally
+startling discovery, which quite upsets all our former ideas of the
+hard and unyielding nature of the rocks composing the earth's crust;
+for we find that not only can they be bent into innumerable folds
+and little puckerings, but that in some cases they have been drawn
+out and squeezed as if they were so much soft putty. The imagination
+almost fails to grasp such facts as these.
+
+Of late years geologists in Switzerland and in Great Britain have
+discovered that in some parts of mountains rocks have been enormously
+distorted and crushed, so that they have assumed very different
+states from those in which they were made, and curious mineral
+changes have taken place under the influence of this crushing.
+
+In the very complicated region of the Northwest Highlands of
+Sutherland and Ross, the structure of which has only lately been
+explained, some wonderful discoveries of this nature have been
+made. Certain of the crystalline schists found there have been
+formed by the crushing down and rearrangement of older rocks that
+once presented a very different appearance. In this district,
+where the rocks have been squeezed by enormous lateral pressure,
+the dislocations sometimes have assumed the form of inclined or
+undulating planes, the rocks above which have been actually pushed
+over those below, and in some cases the horizontal displacement
+amounts to many miles.
+
+Not only have the rocks been ruptured, and older, deep-seated masses
+been torn up and driven bodily over younger strata (that once were
+_above_ them), but there has been at the same time such an amount
+of internal shearing as to crush the rocks into a finely divided
+material, and to give rise to a streaky arrangement of the broken
+particles, closely resembling the flow-structure of a lava. In the
+crushed material new minerals have been sometimes so developed as to
+produce a true schist.[32]
+
+  [32] Geikie.
+
+
+
+
+CHAPTER X.
+
+THE AGES OF MOUNTAINS, AND OTHER QUESTIONS.
+
+    O Earth, what changes hast thou seen!
+
+    TENNYSON.
+
+
+It might naturally be asked at what period in the world's primeval
+or geological history some particular mountain-range was upheaved;
+whether it is younger or older than another one perhaps not very
+far away; and again, whether the mountain-chains of the world have
+been uplifted all at once, or whether the process of elevation was
+prolonged and gradual?
+
+Questions such as these are deeply interesting, and present to the
+geologist some of the most fascinating problems to be met with in the
+whole range of this science. And though at first sight they might
+seem hopelessly beyond our reach, yet even here the prospect is by no
+means unpromising; and it is quite possible to show that they can be
+answered to some extent. Here we shall find our illustration of the
+cathedral (see chapter v., pages 143-147) holds good once more.
+
+It is perhaps hardly necessary to explain that by looking at a
+Gothic cathedral one can say at what period or periods it was built.
+Perhaps it has a Norman nave, with great pillars and rounded arches.
+Then the chancel might be Early English, with pointed windows and
+deep mouldings, and other features that serve to mark the style of
+the building, and therefore its date,--because different styles
+prevailed at different periods. Other parts might contain work easily
+recognised as belonging to the "Perpendicular" period.
+
+Now, as there have been periods in the history of architecture and
+art, so there have been periods in the history of our earth. What
+these periods were, and how we have learned to recognise them, we
+must first very briefly describe.[33]
+
+  [33] For a fuller account see the writer's "Autobiography of the
+  Earth."
+
+There are two simple rules by which the age of an ordinary
+sedimentary rock may be ascertained. This is fixed (1) By its
+position with regard to others; (2) By the nature of its embedded
+animal or vegetable remains, known as fossils.
+
+These rules may easily be illustrated by a reference to the methods
+of the antiquary. For instance, suppose you were going to build
+a house, and the foundations had just been dug out; you might on
+examining them find several old layers of soil, showing that the site
+or neighbourhood had been formerly occupied. You might find in one
+layer stone implements, in another Roman or early British pottery,
+and yet again portions of brick or stonework, together with tools
+or articles of domestic use, belonging, say, to the time of Queen
+Elizabeth. Now, which of these layers would be the oldest? It is
+quite clear that the lowest layers must have been there the longest,
+because the others accumulated on the top of them.
+
+The explorations made of late years under Jerusalem have led to the
+interesting discovery that the modern city is built up on the remains
+of thirteen former cities of Jerusalem, all of which have been
+destroyed in one way or another. Here, again, it is quite clear that
+the oldest layer of débris must be that which lies at the bottom, and
+the newest will be the one on the top.
+
+Again, you know that the "Stone Age" in Britain came before the Roman
+occupation. Those old stone implements were made by a barbarous race,
+who knew very little of agriculture or the arts of civilisation. Then
+in succeeding centuries various arts were introduced, many relics of
+which are found buried in the soil; and hence, since different styles
+of art and architecture prevailed at different periods, the works of
+art or industry embedded in any old layers of soil serve to fix the
+date of those layers.
+
+These layers of soil and débris correspond to the layers or strata of
+the sedimentary rocks, in which the different chapters of the world's
+history are recorded. Geology is only another kind of history; and
+the same principles which guide the archæologist searching buried
+cities also guide the geologist in reading the stony record. As the
+illustrious Hutton said, "The ruins of an older world are visible
+in the present state of our planet." The successive layers of ruin
+in this case are to be seen in the great series of the stratified
+rocks; and we may lay it down as an axiom that the lowest strata are
+the oldest, unless by some subsequent disturbance the order should
+have been reversed, which, fortunately, is a rare occurrence, though
+examples are to be found in some mountain-chains with violent
+foldings.
+
+But it often happens that neither the strata which should come
+above nor those that lie below can be seen. Then our second rule
+comes in: We can determine the age of the rock in question by its
+fossils. The reason of this has perhaps already been guessed by the
+reader. It is that as different kinds of plants and animals have
+prevailed at different periods of the world's history, so there have
+been "styles," or fashions, in creation, as well as in art. At one
+geological period certain curious types of fishes flourished which
+are now almost extinct, only a few old-fashioned survivals being
+found in one or two out-of-the-way places. At another period certain
+types of reptiles flourished vigorously, and were the leaders in
+their day; but they have altogether vanished and become extinct. So
+one type after another has appeared on the scene, played its humble
+part in the great drama of life; and then--"exit!" another takes its
+place.
+
+In the oldest and lowest of the series of rocks we find no certain
+trace of life at all. In the next series we find only lowly
+creatures, such as shell-fish, corals, and crab-like animals that
+have no backbone. In a higher group of rocks fishes appear for the
+first time. Later on, we come across the remains of amphibious
+creatures for the first time. Then follows (after a long unrecorded
+interval) an era when reptiles and birds existed in great numbers.
+After another long interval we come to strata containing many and
+diverse remains of mammals or quadrupeds. So we have an "Age of
+Fishes," an "Age of Reptiles," and an "Age of Mammals." Some tribes
+of these creatures died out, but others lived on to the present day.
+Thus we see that there has been a continuous progress in life as the
+world grew older, for higher types kept coming in.
+
+To the geologist fossils are of the greatest possible use, since they
+help him to determine the age of a particular set of strata, for
+certain kinds of fossils belong to certain rocks, and to them only.
+
+But the classification of the stratified rocks has been carried
+farther than this. Practical geologists, working in the field, use
+fossils as their chief guide in working out the subdivisions of a
+group of rocks, for certain genera and species of old plants and
+animals are found to belong to certain small groups of strata. In
+this way a definite order of succession has been established once
+for all; and, except in the case of inverted strata already alluded
+to, this order is invariably found to hold good.
+
+This great discovery of the order of succession of the British
+stratified rocks, established by their fossil contents, is due to
+William Smith, the father of English geology. After exploring the
+whole of England, he published in 1815 a geological map, the result
+of his extraordinary labours. Before then people had no idea of a
+definite and regular succession of rocks extending over the country,
+capable of being recognised to some extent by the nature of the
+rocks themselves,--whether sandstones, clays, or limestones, etc.,
+but chiefly by their own fossils. They thought the different kinds
+of rocks were scattered promiscuously up and down the face of the
+country; but _now_ we know that they do not show themselves in this
+haphazard way, but have definite relations to each other, like the
+many volumes of one large book.
+
+By combining the two principles referred to above, geologists have
+arranged the great series of British stratified rocks into certain
+groups, each indicating a long period of time. First, they are
+roughly divided into three large groups, marking the three great eras
+into which geological time is divided. Secondly, these eras are
+further divided into certain periods. These periods are again divided
+into epochs, indicated by local divisions of their rocks. In this way
+we have something like a historical table. Omitting the small epochs
+of time, this table is as follows, in descending order:--
+
+_Table of the British Stratified Rocks._
+
+       ERA.         PERIOD.           PREVAILING TYPE.
+
+               { Recent.
+    Cainozoic, { Pleistocene,
+       or      {    or
+    Tertiary.  { Quaternary.          Mammals.
+               { Pliocene.
+               { Miocene.
+               { Eocene.
+
+               { Cretaceous.
+    Mesozoic,  { Neocomian.
+       or      { Jurassic.            Reptiles.
+    Secondary. { Triassic.
+               { Permian.
+
+               { Carboniferous.       Fishes.
+               { Devonian, and
+    Palæozoic, { Old Red Sandstone.
+       or      { Silurian.            Creatures without
+    Primary.   { Cambrian.            a backbone
+               { Archæan,[34]          (invertebrates).
+               {    or
+               { Pre-Cambrian.
+
+  [34] The Archæan rocks are frequently placed in a separate group
+  below the Palæozoic.
+
+The total thickness of all these rocks has been estimated at about
+one hundred thousand feet, or not far from twenty miles. These
+names have been given partly from the region in which the rocks
+occur, partly from the nature of the rocks themselves, and partly
+for other reasons. Thus the Old Red Sandstone is so called, because
+it generally, though not always, appears as a dark red sandstone.
+But the Silurian rocks, which we find in North Wales, receive
+their name from the Silures, an ancient Welsh tribe; the Cambrian
+rocks take theirs from Cambria, the old name for North Wales. The
+Cretaceous rocks are partly composed of chalk, for which the Latin
+word is _creta_; and so on. The terms "Palæozoic," "Mesozoic," and
+"Cainozoic" mean "ancient life," "middle life," and "recent or new
+life," thus indicating that as time went on the various types of
+life that flourished on the earth became less old-fashioned, and
+more like those prevailing at the present time. These used to be
+called "Primary," "Secondary," and "Tertiary;" but the terms were
+unfortunate, because the primary rocks, as then known, were not the
+first, or oldest. We have therefore included the Archæan rocks,
+since discovered, in this primary group. Only one fossil has been
+found in these rocks, and that is a doubtful one; hence they are
+sometimes called "Azoic," that is, "without life." The Mesozoic rocks
+are, as it were, the records of the "middle ages" in the world's
+history; while the Palæozoic take us back to a truly primeval time.
+
+We have now learned how the geological age of any group of rocks
+may be determined. Thus, if a series of rocks of unknown age can be
+shown to rest on undoubtedly Silurian rocks in one place, and in
+another place to be overlaid or covered by undoubtedly Carboniferous
+rocks, they will probably belong to the Old Red Sandstone Period. If
+afterwards we find that they contain some of the well-known fossils
+of that period, the question of their age is settled at once. But we
+want more evidence than this. Suppose, now, we find somewhere on the
+flanks of a mountain-range a series of Permian and Triassic rocks,
+resting almost horizontally on disturbed and folded Carboniferous
+strata. Does not that at once prove that the upheaval took place
+before the Permian Period? Clearly it does, because the Permian rocks
+have evidently _not_ been disturbed thereby. So now we can fix the
+date of our range of hills; namely, after the Carboniferous Period
+and before the Permian Period.
+
+It is by such reasoning that the age of our Pennine range of hills,
+extending from the north of England into Derbyshire, has been fixed;
+for the Permian and Triassic strata lie undisturbed on the upheaved
+arch of Carboniferous rocks of which this chain is composed. Its
+structure is that of a broken and much denuded anticline, which
+stands up to form a line of hills only because the Carboniferous
+limestone is so much harder than the "coal measures," or coal-bearing
+rocks, on each side of it, that it has not been worn away so fast. In
+time, this great anticline will be entirely worn away like that of
+the Weald. It is called the Great Mountain Limestone, because it so
+often rises up to form high ground. The Mendip Hills in Somersetshire
+are of about the same date, and they too are largely composed of this
+great limestone formation.
+
+Of course, a certain amount of up and down movement took place after
+the hills were upheaved, otherwise the Permian and Triassic rocks
+could not have been deposited on their sides; but these movements
+were slight and of a more general kind than those by which strata are
+thrown into folds.
+
+The main upheaval, by which the rocks now forming the Highlands of
+Scotland were lifted up and contorted, took place after the Lower
+Silurian Period, and before that of the Old Red Sandstone; and there
+is clear evidence that even before the latter period they had not
+only been greatly altered, or "metamorphosed," by subterranean heat,
+but that they had suffered enormous denudation. And the work of
+carving out these mountains has gone on ever since; for even in Old
+Red Sandstone times they were probably not entirely covered by water.
+The Highland Mountains are therefore older than the Pennine range.
+
+Geologically Scotland belongs in great part to Scandinavia; and
+the long line of Scandinavian Mountains is a continuation of the
+Highlands, and so is of the same age.
+
+Mountain-chains and hill-ranges have been upheaved at various
+geological periods; and some are very old, while others are much
+younger.
+
+Turning to the southeast of England, we find the ranges of chalk
+hills forming the North and South Downs (see page 237). As explained
+previously, these owe their existence to the upheaval and subsequent
+denudation of the low arch, or anticline, of the Weald. They are
+called "escarpments," because they are like lines of cliffs that are
+being gradually cut back. Now, it is clear that these hills are much
+newer than either of those we have just considered. Look at the table
+on page 324, and you will see that the Cretaceous rocks (chalk, etc.)
+belong to the Mesozoic era. The chalk was the last rock formed during
+the Cretaceous Period.
+
+So the Wealden arch must have been heaved up after the chalk was
+formed; that is, ages and ages later than the date of the Pennine
+range or the Scotch Highlands. From other evidences it has been shown
+that this anticline was heaved up in the early part of the Cainozoic
+Era, perhaps during the Miocene Period.
+
+Let us now take the case of the Alps. And here we have an instructive
+example of a great mountain system formed by repeated movements
+during a long succession of geological periods. We cannot say
+that they were entirely raised up at any one time in the world's
+past history. In the centre of this great range we find a series
+of igneous and metamorphic rocks, such as granite, gneiss, and
+crystalline schists. Some of these may belong to the very oldest
+period,--namely, the Archæan; others are probably Palæozoic and
+Cainozoic deposits greatly altered by heat and pressure.
+
+The ground from Savoy to Austria began to be an area of disturbance
+and upheaval towards the close of the Palæozoic Era, if not before;
+so that crystalline schists and Carboniferous strata were raised
+up to form elevated land around which Permian conglomerates and
+shingle-beds were formed,--as on the seashore at the present day.
+
+During the early part of the Mesozoic Era local fractures and certain
+up and down movements occurred. After this there was a long period
+of subsidence, during which a series of strata known as Oölites and
+Cretaceous were deposited on the floor of an old sea.
+
+Towards the close of this long era, a fresh upheaval took place along
+the present line of the Alps,--an upheaval that was prolonged into
+the Eocene Period. It was during this latter period that a very
+extensive formation known as the "Nummulitic limestone" was formed in
+a sea that covered a large part of Europe and Asia. We have already
+referred (see chap. v., pp. 169-171) to the way in which limestones
+have been formed. Nummulites are little shells that were formed by
+tiny shell-fish.
+
+But after this, the greatest upheaval and disturbance took place,--an
+upheaval to which the Alps as we now see them are chiefly due. By
+this means the older Cainozoic strata, once lying horizontally on the
+floor of the sea, were raised up, together with older rocks, to form
+dry land, and not only raised up, but crumpled, dislocated, and in
+some cases turned upside down.
+
+So intense was the compression to which the Eocene rocks were
+subjected that they were converted into a hard and even crystalline
+state. It seems almost incredible that these highly altered rocks
+which look so ancient are of the same date as our London clay and
+the soft Eocene deposits of the south of England; but in our country
+the movement that raised up those strata was of the most feeble and
+gentle kind compared to the violent disturbances that took place in
+Switzerland.
+
+And here we may point out that the Alps are only a portion of a
+vast chain of mountains stretching right across Europe and Asia in
+a general east and west direction, beginning with the Pyrenees and
+passing through the Alps, the Carpathians, the Caucasus, and the
+range of Elbruz to the Hindoo-Koosh and the high plateau of Pamir,
+called "the roof of the world," which stands like a huge fortress,
+fifteen thousand feet high. Thence it passes to the still higher
+tracts of Thibet, great plains exceeding in height the highest
+summits of the Alps, being enclosed between the lofty ramparts of
+the Himalayas on the south and the Kuen-Lun Mountains on the north;
+and thence the mountain wall is prolonged in the Yuen-Ling, In-Shan,
+Khin-Gan, and other ranges till it finally passes to the Pacific
+Ocean at Behring's Strait.
+
+All these ranges are, as it were, the backbone of the great
+continental plateau of the Old World, and doubtless are chiefly due
+to those earth-movements by means of which the Alps were upheaved.
+The last grand movement, which raised the Mont Blanc range, was
+probably rather later, and seems to have taken place as late as the
+Pliocene Period.
+
+At the present day no great movements are taking place in the Alps;
+but now and then earthquakes visit this region, and serve to remind
+us that the process of mountain-making is still slowly going on.
+
+Probably there have been times in the history of all these
+mountain-ranges when movements took place of a more violent and
+convulsive kind than anything with which we are familiar at the
+present day; and the age we live in may be one of comparative
+repose. This is of course somewhat a matter of speculation; and we
+only allude to it because there has been a tendency on the part of
+some to carry the theory of uniformity in all geological operations
+much farther than Hutton or Lyell ever intended. But at the same
+time there is no need to go back to the old teaching of sudden
+catastrophes and violent revolutions. We only wish to avoid either of
+these two extremes and to take a safe middle course.
+
+How rapidly some of these great earth-movements took place it is
+impossible at present to say; but in several cases it can be shown
+that they were quite slow, as indicated by the testimony of the
+rivers. Thus, the rise of the great Uintah Mountains of the Western
+States was so slow and gradual that the Green River, which flowed
+across the site of the range, so far from being turned aside as they
+rose up, has actually been able to deepen its cañon as fast as the
+mountains were upheaved. So that the two processes, as it were, kept
+pace with each other, and the river went on cutting out its gorges
+at the same time that the ground over which it flowed was gently
+upheaved; and as the land rose the river flowed faster, and therefore
+acquired more power to cut and deepen its channel. This is a valuable
+piece of evidence; but in this case we have only a few big broad
+folds, instead of the violent folding seen in the Alps. However,
+certain Pliocene strata lying on the southern flanks of the Himalayas
+show that the rivers still run in the same lines as they occupied
+before the last great upheaval took place.
+
+We have seen how the substance of the mountains was slowly
+manufactured by means of such quiet and gentle operations as may
+be witnessed at the present day; how the rivers of old brought
+down their burdens as they do now, and flung them into the sea; how
+the sea spread them out very slowly and compacted them into level
+layers, to form, in process of time, the hard rocky framework of
+the plateaux, hills, and mountains of the world; how vast marine
+accumulations were also slowly manufactured through the agency of
+countless generations of humble organisms, subtracting carbonate of
+lime from sea water to form the limestones of future ages; how by
+slow earth-movements these marine deposits were reared up into dry
+land; how they have frequently been penetrated by molten rocky matter
+from below, which occasionally forced its way up to the surface
+and gave rise to various volcanic eruptions, by means of which the
+sedimentary rocks were often considerably baked and hardened, and new
+fissures filled up with valuable metallic ores and precious stones;
+how lava-flows and great deposits of volcanic ash were mingled with
+these sedimentary rocks.
+
+Then we endeavoured to follow the history of these rocky layers after
+their upheaval, and learn how they are affected by the ceaseless
+operations of rain and rivers and other agents of destruction, so
+that finally the upheaved ridges of the lands are carved out into all
+those wonderful features of crag and pinnacle and precipice that give
+the mountains their present shapes and outlines. All this we were
+able to account for, without the aid of any imaginary or unnatural
+causes.
+
+And, lastly, we have seen that even where such causes might seem
+at first almost indispensable,--when mountains tell us of mighty
+internal forces crumpling, folding, and fracturing their rocky
+framework,--yet even there we can account for what we see without
+supposing them to have been torn and tossed about by any very violent
+convulsions.
+
+  [Illustration: MOUNTAIN IN THE YOSEMITE VALLEY.]
+
+Although the question of the cause, or causes, of earth-movements,
+whereby continents are upheaved, and the contorting, folding, and
+crumpling of the rocks of mountains produced, is not at present
+thoroughly explained, it may perhaps be worth our while to consider
+briefly some of the views that have been put forward on this
+difficult subject. The words "upheaval" and "elevation," in reference
+to movements of the earth's surface, are somewhat misleading, but are
+used for want of better terms. They would seem to imply that the
+force which produced mountains was a kind of upward push; whereas, in
+most cases, and perhaps in all, the force, whatever it was, did not
+act in an upward direction. So it should be understood that we employ
+these terms only to indicate that the rocks have somehow been carried
+up to a higher level, and not as suggesting _how_ the force acted by
+which they were raised.
+
+It seems pretty clear that in the case of mountain-chains, at least,
+the force acted in a horizontal direction, as a kind of side-thrust.
+
+This we endeavoured to illustrate in chapter ix. by means of a simple
+experiment with a sheet of paper; and it was shown how folds similar
+to those of which Mont Blanc is composed could be imitated by simply
+pressing the sides of a sheet of paper inwards with one's two hands
+as it lies on a table. Such lateral pressure, it is thought by many,
+must be caused by the shrinking of the lower and hotter parts of the
+earth's crust as they cool, leaving the outer crust unsupported, so
+that it gradually settles down onto a smaller surface below, and in
+so doing must inevitably be wrinkled and throw itself into a series
+of folds (see chapter vi., page 204).
+
+The interior of the earth is hotter than the outside; and since there
+is good reason to think that the whole earth was once upon a time in
+a highly heated and perhaps half molten condition, we are compelled
+to believe that it always has been, and still is, a cooling globe.
+Now, almost all known substances are found to contract more or less
+on cooling; and so if the materials of which the earth is mainly
+composed are at all similar in their nature and properties to those
+which we find on its surface, it follows that the earth must be
+contracting at the same time that it is cooling, just as a red-hot
+poker will contract on being taken out of the fire.
+
+Moreover, we find that hot bodies contract faster than those that are
+merely warm, so that a red-hot poker contracts more during the first
+few minutes after it is taken out of the fire than it does after
+it has passed the red-hot stage. Hence it is easy to see that the
+interior portions of the earth, which are hotter, must be contracting
+at a greater rate than its external parts, for they evidently have
+very little heat to lose. This may seem rather puzzling to the reader
+at first; for it might be argued that the heat from below _must_ pass
+through the external layers, or crust, as it is often called. But it
+should be remembered that this is not the only way in which the earth
+loses heat. Think of the vast amount of heat given out from the earth
+every year by volcanic eruptions, and you will see at once that much
+of the cooling takes place in this way, and not as a direct flow of
+heat from the interior, as in the case of the poker. A single big
+lava-stream flowing out from a volcano, and cooling on the surface
+of the earth, represents so much heat lost forever; and so do the
+clouds of steam emitted during every eruption; so, again, do even the
+hot springs that are continually bringing up warm water. If, then,
+the lower portions of the earth are slowly contracting, they must
+tend to leave the outer portions of the crust unsupported, so that
+they would be compelled by their own enormous weight to settle down.
+Now, we know that something like this happens in coal mines; and as
+long passages are hollowed out below, the ground begins to "creep,"
+or slowly sink. Think what would be the effect of a slow sinking of
+any portion of the earth down towards the centre; it would inevitably
+be curved up and down into numerous folds, as it endeavoured to get
+itself onto a smaller space, much in the same way that a table-cloth,
+when thrown onto a table in a kind of arch, settles down in a series
+of waves, or folds. And this, it is thought, is the way in which
+it happens that the pressure comes, as we said just now, sideways,
+instead of from below upwards. It is on this theory that many
+geologists account for the enormous side-pressure to which rocks have
+in many cases been subjected.
+
+The evidences of such pressure are many. In some cases fossils
+have been thereby pulled out of shape and appear considerably
+distorted; in others, even hard quartz pebbles have been considerably
+elongated (see chap. ix., pp. 315-316). Then again, we have the
+little crumplings of all sizes so frequently seen in mica-schists.
+And lastly, the peculiar property that slates possess of splitting
+up into thin sheets is found to be due to the same cause; namely,
+lateral pressure. Slates were originally formed of soft dark mud, and
+on being subsequently squeezed, by earth-movements, have assumed
+a structure known as "cleavage," whereby their tiny mud-particles
+were elongated, and all assumed the same direction, thus giving to
+the rock this peculiar property of splitting. It can be proved that
+the pressure came in a direction opposite to that of the planes
+of cleavage; and it is found that the direction of the cleavage
+corresponds in a general way with the direction, or trend, of a
+mountain-chain which is composed partly of slates, as in North Wales.
+And this discovery helps and harmonises with what we have already
+said about the cause of the folds in mountain-chains, for the same
+force, acting sideways, produced the cleavage and the folding, etc.
+
+It has been already stated that in a large number of cases a
+mountain-range has a central axis, or band, of granite or other
+crystalline rock. This led some people to suppose that the granite
+had been driven up from below, and in so doing had thrust up the
+overlying rocks seen on either flank of the chain; in other words,
+they believed granite to have been the upheaving agent. And even now
+we often find unscientific writers speaking of the volcanic forces of
+upheaval.
+
+Having very little idea of the true structure of mountains, they
+believed them to consist of a kind of core, or axis, of this igneous
+rock, with sedimentary rocks sloping away from it on each side.
+This was a very simple theory of mountain-chains, but unfortunately
+it will not bear examination. It takes no notice of the folding
+which is so characteristic of mountain strata, and is quite out of
+agreement with the facts of the case; so it must be buried among the
+archives of the past. Mountain-chains are now known to have a much
+more complicated structure than this,--thanks to the labours of many
+subsequent observers.
+
+That illustrious astronomer, the late Sir John Herschel, threw out
+a bold suggestion on this subject, which in the light of recent
+discoveries with regard to the delicate adjustment between the
+internal and external forces affecting the earth's surface, is
+worthy of careful consideration. His idea was that the mere weight
+of a thick mass of sediment resting on any portion of the earth's
+crust might cause a certain amount of sinking; and that this would
+cause portions on either side to swell up. It is certain that as
+great deposits of sedimentary materials accumulate on the floor of
+an ocean, that floor slowly sinks, otherwise the sea would become
+choked up, and dry land would take its place. Now, it is found that
+every great mountain-chain consists of many thousands of feet of
+strata thus formed; and more than this: it turns out that a greater
+thickness of such materials has been formed in regions where we
+now see mountain-chains than in those continental regions that lie
+farther away from them. This is an important fact, which was not
+known in Sir John Herschel's time. One striking example may be
+mentioned here. In the complicated region of the Appalachian chain
+the strata are estimated to have a total thickness of eight miles;
+while in Indiana, where the same strata are nearly horizontal, they
+are less than one mile thick. Hence it is not impossible that in the
+mere accumulation, through long periods of time, of vast masses of
+strata many thousands of feet thick, we may find a potent cause of
+earth-movements.
+
+The marginal regions of oceans, where most deposition takes place,
+seem to undergo slow subsidence, while the continents seem in most
+places to be as slowly rising. Modern geologists are inclined to
+think that as denudation wears down a continental surface, removing
+from it a great quantity of solid rocky matter (see chap. v., pp.
+161-163), the pressure below is somewhat lessened, or in other words,
+so much weight is taken off; but that, on the other hand, as this
+extra amount of material accumulates on the bed of a neighbouring
+ocean the pressure is increased by a corresponding amount, and so the
+balance between internal and external forces is upset, and movements
+consequently take place. We have already seen that the external parts
+of the earth are much more subject to movements than might have been
+expected; and for our part, we are willing to believe that in this
+simple way upheaving forces might be called into play sufficient to
+account for even the elevation of mountain-chains. For suppose a
+great mass of strata to continue sinking as they were formed, for
+long periods of time; what seems to follow? The downward movement
+would go on until a time would come when the strata, in endeavouring
+to settle down at a lower level, would (as by the contraction
+theory above explained) be forced to fold themselves into ridges,
+and in this way long strips of them might even be elevated into
+mountain-ranges.
+
+Another ingenious idea was suggested by the late Mr. Scrope, whose
+work on volcanoes is well known. His idea was that when a large
+amount of sedimentary material has accumulated on any large area
+of the bed of the ocean, it somewhat checks the flow of heat from
+within, and therefore the temperature of the rocks forming part of
+the earth's crust below will be increased, much in the same manner as
+a glove checks the escape of heat from the hand and keeps it warm.
+The consequence of this would be expansion; and as such expansion
+would be chiefly in a horizontal direction, the area would bulge
+upwards and cause elevation of the strata resting on it. But there
+are several difficulties which this theory fails to explain.
+
+And lastly, Professor Le Conte, holding that the contraction theory
+is unsatisfactory, accounts for earth-movements of all kinds by
+supposing that some internal parts of the earth cool and contract
+faster than others. Those parts that cool fastest, according to this
+theory, are those that underlie the oceanic basins or troughs; while
+the continental areas, not cooling so rapidly, are left standing up
+in relief. This theory, which does not seem very satisfactory, is
+based upon the idea that some parts of the earth's interior may be
+capable of conducting heat faster than others. We know that some
+substances, like iron, are good conductors of heat, while others are
+bad conductors; and it is therefore conceivable that heat may be
+flowing faster along some parts of the earth than along others; and
+if so, there would be differences in the rate of contraction.
+
+
+There are various theories with regard to the nature of the earth's
+interior. One of these already referred to, but now antiquated,
+supposes our planet to consist of a thin, solid crust lying on a
+molten interior, so that the world would be something like an egg
+with its thin shell and liquid, or semi-liquid, interior. Now, there
+are grave reasons for refusing to accept this idea. In the first
+place, a certain slow movement of the earth known as "precession,"
+because it causes the precession of the equinoctial points on the
+earth's orbit, could not possibly take place as it does if the
+earth's interior were in this loose and molten condition. That is
+a matter decided by mathematical calculation, on which we will not
+dwell further. Secondly, we obtain some very valuable evidence on
+this abstruse subject from the well-known daily phenomenon of the
+tides, caused, as the reader is probably aware, by the attractions of
+the sun and moon; but much more by the moon, because she is nearer,
+and so exerts a greater pull on the ocean as each part of the world
+is brought directly under her by the earth's daily rotation on its
+axis. The waters of our oceans rise up twice each day as they get
+in a line with the moon, and then begin to fall again. Thus we get
+that daily ebb and flow seen on our shores. Now, it has been clearly
+proved by Sir William Thomson, and others, that if any considerable
+portion of the interior of the earth were in a fluid condition, it
+too would rise and fall every day as the ocean does. So we should in
+that case have a tide _below_ the earth as well as on its surface,
+and the one would tend to neutralise the other, and the ocean tide
+ought to appear less than it actually is. Even if the earth's crust
+were made of solid steel, and several hundreds of miles thick, it
+would yield so much to the enormous pulls exerted by both the sun
+and moon that it would simply carry the waters of the ocean up and
+down with it, and we should therefore see no appreciable rise and
+fall of the water relatively to the land. As a matter of fact, there
+_is_ a very slight tide in the solid earth below our feet, but so
+slight that it does not practically affect the tide which we see
+every day in the ocean. But we wish to show that were the interior of
+the earth in anything approaching, to a fluid or molten condition,
+the phenomena of the tides would be very different from what they
+actually are.
+
+All geologists are therefore agreed that we must consider our earth
+as a more or less solid body, and not as being something like an
+india-rubber ball filled with water.
+
+The only question is whether it is entirely solid throughout. Some
+authorities consider this to be the case. But others venture to think
+that while the great mass of the globe is solid, there may be a thin
+liquid layer lying somewhere below the surface. Sir William Thomson
+calculates that there must be a solid crust at least two thousand or
+twenty-five hundred miles thick (the diameter of the earth is about
+eight thousand miles) and that the mass of the earth "is on the whole
+more rigid certainly than a continuous solid globe of glass of the
+same diameter."
+
+
+One other question with regard to the earth's interior may be
+mentioned in conclusion. Astronomers have calculated the weight of
+our planet, and the result is curious; for it turns out to be _at
+least twice as heavy as the heaviest rocks that are found on or near
+the surface_. It is about five and a half times as heavy as a globe
+of water of the same size would be, whereas most rocks with which
+we are acquainted are about two and a half, or at most three times
+heavier than water. This fact seems to open out curious consequences;
+for instance, it is quite possible that metals (which are of course
+much heavier than water) may exist in the earth's interior in
+considerable quantities. The imagination at once conjures up vast
+quantities of gold and silver. What is the source of the gold and
+silver, and other metals found in mineral veins? This question cannot
+as yet be fully answered. Very small quantities of various metals
+have been detected in sea-water; and so some geologists look upon the
+sea as the source from which metals came. But it is possible that
+they were introduced from below,--perhaps by the action of steam and
+highly heated water during periods of volcanic activity,--and that
+their source is far down below in the depths of the earth.
+
+But perhaps we have already wandered too far into the regions of
+speculation.
+
+Such are some of the interesting problems suggested by the study of
+mountains, and they add no small charm to the science of geology.
+
+And as we leave the mountains behind us, refreshed by their bracing
+air, and strengthened for another season of toil and labour by
+a brief sojourn among their peaks and passes, we come away with
+a renewed sense of the almost unlimited power of the unhasting
+operations of Nature, and the wisdom and beneficence of the Great
+Architect of the Universe, who made and planned those snowcapped
+temples as symbols of His strength, who was working millions of years
+ago as He is working to-day, and to whom a thousand years are as one
+day.
+
+
+
+
+INDEX.
+
+
+    Agents of transportation, 161.
+
+    Ages of strata, how determined, 317-333.
+
+    Air, composition of, 209.
+
+    Alpine animals, 124. plants, 103, 114.
+
+    Alps, the history of, 330.
+      (See also Ruskin.)
+
+    Ancients, the, their dread of the mountains, 3.
+
+    Andes, the, elevation of, 189.
+
+    Animals, behaviour of, before an avalanche or earthquake, 95.
+
+    "Anticline," 237, 303, 327.
+
+    Appalachian Mountains, denudation of the, 239, 305-309.
+
+    Aqueous rocks, 154.
+
+    Archæan Era, 324.
+
+    Arctic flora, 121.
+
+    "Arthur's Seat," 277.
+
+    Ashes, volcanic, 245, 251, 260.
+
+    Atlantic ooze, 172.
+
+    Atmosphere, effects produced by the, 209.
+      rarefaction of, 79.
+
+    Avalanches, 89.
+
+
+    Badger, the, in Alps, 128.
+
+    Baltic Sea, changes in, 182.
+
+    Barrier reef, of Australia, 170.
+
+    Basalt, of Hebrides, 278.
+      of Snowdon, 272.
+
+    Basin, the Great, of United States, 313.
+
+    Bear, brown, 125.
+      black, 126.
+
+    Beaver, the, in Alps, 128.
+
+    Bergfalls, 97.
+
+    Bernina, the, fall of rocks from, 98.
+
+    Bird, Miss (Mrs. Bishop), on eruption of Kilauea, 262.
+
+    Birds, of Alps, 134.
+
+    Blueness of the sky, 75.
+
+    Bombs, volcanic, 253.
+
+    Bonney, Prof., on mountain legends, 23.
+      on effects of the Alps in Europe, 48.
+      on wind on mountain-tops, 84.
+      on Alpine plants, 115.
+      on forms of mountains, 294.
+
+    Boulders, erratic, 225.
+
+    Bouquetin, the, in Alps, 133.
+
+    Britain, Great, rainfall of, 42.
+
+    Building up of mountains, 174.
+
+    Butterflies, in Alps, 138.
+
+    Buzzard, the, in Alps, 136.
+
+
+    Cader Idris, volcano rocks of, 272.
+
+    Cainozoic Era, 324.
+
+    Callao, 189.
+
+    Cambrian rocks, 296, 324.
+
+    Canisp Mountain, 297.
+
+    Cañons of Colorado, 221.
+
+    Carbonic acid in atmosphere, 210.
+
+    Carboniferous Period, 324.
+
+    Catastrophes, 215.
+
+    Caves, human remains, etc., in, 31.
+
+    Celsius, on elevation of Gulf of Bothnia, 178.
+
+    Chalk, Cretaceous rocks composed of, 325.
+      origin of. See Limestones.
+
+    Challenger, H. M. S., expedition of, 251.
+
+    Chamois, the, in Alps, 130.
+
+    Characteristics of mountain races, 14.
+
+    China clay, 292.
+
+    Classification of rocks, 157.
+
+    Cleavage of slates, 151, 340.
+
+    Coniferous trees, region of, 111.
+
+    Contortions in strata, 298, 311.
+
+    Contraction and expansion of rocks, 208.
+
+    Contraction theory of earth-movements, 338.
+
+    Coral reefs, 170.
+
+    Cotopaxi, 259.
+
+    Crystalline schists, 312.
+
+
+    Darwin, Charles, on elevation of the Andes, 189.
+
+    Deciduous trees, mountain region of, 110.
+
+    Dent de Mayen, 99.
+
+    Dent du Midi, fall of rock from, 98.
+
+    Denudation, 220, 229, 288, 312.
+
+    Devonian rocks, 324.
+
+    Diablerets, fall of rock from, 98.
+
+    Dislocations of mountain rocks, 313, 315.
+
+    Dust, volcanic, 245, 260.
+
+    Dykes, 245.
+
+
+    Eagle, the golden, 136.
+
+    Earth-pillars in Tyrol, 221.
+
+    Earthquakes, 95, 102, 196.
+      effects of, 198, 336.
+      causes of, 198, 200.
+      Lucretius on, 199.
+
+    Earth-tremors, 194.
+
+    Elevation of mountains, 146, 200, 202, 299, 336.
+      continents, 298-299.
+
+    Encrinites, 171.
+
+    Eocene Period, 324.
+
+    Equador and Peru, earthquake of, 197.
+
+    Eras, geological, 324.
+
+    Eruptions, volcanic, 247.
+
+
+    Fairies, 5.
+
+    Falcon, the, in Alps, 136.
+
+    "Fan-structure," 310.
+
+    "Faults" and fractures, 200, 313.
+
+    Features characteristic of mountains, 177.
+
+    Ferns, 118.
+
+    Fishes, Age of, 322.
+
+    Fissures, 268.
+
+    Föhn, the, 84.
+
+    Foraminifera, 172.
+
+    Fox, the, in Alps, 127.
+
+    Frog, the, in Alps, 137.
+
+    Frost, effects of, on mountain rocks, 212.
+
+
+    Game-birds, in Alps, 137.
+
+    Ganges and Brahmapootra, 167.
+
+    Geikie, Sir A., on influence of Scottish scenery, 21.
+      on the Highland plateau, 284.
+      on the mountains of West Sutherland, 296.
+
+    Giant's Causeway, basalt of, 279.
+
+    Glace, Mer de, 229.
+
+    Glacial drifts, 227.
+
+    Glacial region of vegetation in Alps, 116.
+
+    Glaciers, erosive power of, 228.
+
+    Glare from snow in Alps, 76.
+
+    Gneiss, 156, 292.
+
+    Gold and silver in mountains, 61.
+      in the earth, 350.
+
+    Grampians, 276.
+
+    Granite, 210.
+      weathering of, 291.
+      in mountain-chains, 312.
+
+    Greenland, elevation of, 186.
+
+    Green slates and porphyries, 275.
+
+    Gulf Stream, 42.
+
+
+    Hare, the, in Alps, 128.
+
+    Hawaii, 256.
+
+    Heat, effects of, on rocks, 154, 156, 160.
+      underground, of the earth, 338, 345.
+
+    Hebrides, former volcanic action in, 278.
+
+    Height, influence of, on vegetation, 107.
+
+    Herculaneum, 254.
+
+    Highest cluster of houses in the world, 79.
+
+    Highlands of Scotland, 284.
+
+    Himalayas, description of, 6.
+
+    Hutton, 142, 320.
+
+
+    Iberian, or pre-Celtic race, 30.
+
+    Ice Age, the, 65, 123.
+
+    Ice, as a geological agent, 223.
+
+    Igneous rocks, 155.
+
+    Imbaburu, eruption of mud from, 259.
+
+    Implements of stone, 31.
+
+
+    Jackdaw, the, in Alps, 136.
+
+    Jura Mountains, 300, 306.
+
+    Jurassic rocks, 324.
+
+
+    Kilauea, eruption of. (See Bird, Miss.)
+
+    Kite, the, in Alps, 136.
+
+    Krakatoa, 252.
+
+
+    Labrador, elevation of, 192.
+
+    Lake District, denudation of, 220.
+      volcanic rocks of, 275.
+
+    Lakes, origin of, 47.
+
+    Lateral pressure, applied to mountains, 310, 315, 337.
+
+    Lichens and mosses. (See Ruskin.)
+
+    Limestones, origin of, 151, 153, 169.
+
+    Lisbon, earthquake at, 197.
+
+    Livingstone, on splitting of rocks, 212.
+
+    Lizard, the, in Alps, 137.
+
+    Lyell, Sir Charles, 333.
+
+    Lynx, the, in Alps, 128.
+
+
+    Mal de montagne, 80.
+
+    Mammals, age of, 322.
+
+    Marmot, the, in Alps, 129.
+
+    Mauna Loa, eruption of, 256.
+
+    Mendip Hills, 327.
+
+    Mer de Glace. (See Glace.)
+
+    Metals, precious, 60.
+      in the earth, 349.
+
+    Metamorphic rocks, 156, 157, 298, 330.
+
+    Mica-schist, 156, 293.
+
+    Miller, Hugh, 150.
+
+    Milne, Prof., on earth-pulsations, 193.
+
+    Minor cones of volcanoes, 246.
+
+    Miocene Period, 278, 324.
+
+    Mississippi, denudation by the, 232.
+
+    Moel Tryfaen, raised beach in, 186.
+
+    Mont Blanc, 310.
+
+    Monte Conto, downfall of, in 1618, 101.
+
+    Monte Nuovo, 248.
+
+    Moraines, 225.
+
+    Mountain limestone, 152.
+
+    Mountains, as barriers between nations, 26.
+      as reservoirs of water, 43.
+      human wants supplied by, 58.
+      influence of, on climate, 62.
+      causing movements in the atmosphere, 65.
+      as backbones of continents, 67.
+      floras of, 103-124.
+      forms of, how determined, 282.
+      general features of, 177, 283.
+      structure of, how determined, 308.
+      elevation of, 174, 313.
+      formed by huge dislocations, 313.
+      Ruskin on uses of, 68.
+        " on a scene on the Jura, 300.
+        " on flowers of, 107.
+
+    Mud-flows from volcanoes, 259.
+
+
+    "Needles," the, of Colorado, 221.
+
+    Neptunists and Plutonists, 160.
+
+    New England, elevation of, 192.
+
+    New Zealand, elevation of, 190.
+
+    Nummulites, 331.
+
+
+    Old Red Sandstone, 150, 324.
+
+    Olive region, the, 107.
+
+    Organically formed rocks, 157.
+
+    Ornamentation of mountains, 147.
+
+    Oxygen, in air, 209.
+
+
+    Palæozoic Era, 324.
+
+    Permian rocks, 324.
+
+    Pleistocene rocks, 324.
+
+    Pliocene, 324.
+
+    Plutonists, 160.
+
+    Pompeii, buried up, 254.
+
+    Precious stones in mountains, 277.
+
+    Primary Era, 324.
+
+    Pulsations of the earth. (See Milne.)
+
+
+    Quinag, 297.
+
+
+    Rabbit, the, in Alps, 128.
+
+    Raised beaches, 185.
+
+    Raven, the, in Alps, 136.
+
+    Red clay, of Atlantic Ocean, 252.
+
+    Reptiles, Age of, 323.
+
+    Righi Mountain, fall of rock from, 99.
+
+    Rivers, transporting power of, 161-168.
+
+    Roches Moutonnées, 227.
+
+    "Rocking Stones," 292.
+
+    Ross and Sutherland, mountains of, 315.
+
+    Rossberg, the, fall of rock from, 99-101.
+
+    Ruskin, on effect of tourists in Switzerland, 21.
+      on effects of scenery on mythology, 22.
+      on uses of mountains, 50.
+      on formation of soil, 55.
+      on lichens and mosses, 119.
+      on the Alps, 289.
+      on a scene in the Jura Mountains, 300.
+
+
+    Santorin, island of, 257.
+
+    Scandinavia, elevation of, 180.
+
+    Scenery, influence of rocks on, 219.
+
+    Schists. (See Mica-schist.)
+
+    Scotland, former volcanic action in, 275.
+
+    Sea-beaches, 183.
+
+    Sea-level, constancy of, 179.
+
+    Secondary Era, 324.
+
+    Serapis, Temple of, 187.
+
+    Silurian Period, 324.
+      volcanic rocks of, 272.
+
+    Shearing of rocks in mountains, 316.
+
+    Skaptar Jökull, lava-flow from, 255, 260.
+
+    Smith, William, 323.
+
+    Snake River Plain, 258.
+
+    Snow, lambent glow of, 77.
+
+    Snowdon, volcanic rocks of, 272.
+      denudation of, 239.
+
+    Spectre of the Brocken, the, 78.
+
+    Stability of the earth, 174, 314.
+
+    Stanley, Dean, on capture of Canaan, 32.
+
+    Stone Age, 31.
+
+    Storms on mountains, 81.
+
+    Stratified rocks, table of, 324.
+      how formed, 148, 176.
+
+    Striæ, glacial, 227.
+
+    Submerged forests, 192.
+
+    Suilven Mountain, 297.
+
+    Sunsets, 71.
+
+    Sutherland, West, mountains of, 296.
+
+
+    Taurentum, destroyed by downfall of rocks, 97.
+
+    Thames, solid matter transported by, 168.
+
+    Thunder-storms, in Alps, 86.
+
+    Tomboro, eruption at, 260.
+
+    "Tors," 292.
+
+    Tourmente, the, 83.
+
+    Transportation by rivers, 161, 166-169.
+      by glaciers, 224.
+
+    Triassic Period, 324.
+
+    Types of plants and animals at different periods, 106.
+
+
+    Upheaval theory of mountains, 247.
+
+    Uses of mountains, 33.
+
+
+    "Valleys, how carved out, 214-230.
+
+    Vesuvius, history of, 250.
+
+    Vines, the region of, in Alps, 109.
+
+    Volcanoes, number of active, 242.
+      old ideas about, 244.
+      structure of, described, 244.
+      volcanic rocks of Great Britain, 271.
+
+    Vulture, the bearded, 134.
+
+
+    Wall of Antoninus, 185.
+
+    Waterfalls, origin of, 218.
+
+    Water-vapour, in air, 34.
+      condensation of, by mountains, 34.
+
+    Waves of population, 30.
+
+    Weald, the denudation of, 235-239.
+      structure of, 303.
+
+    Werner, 158.
+
+    Wild-cat, in Alps, 128.
+
+    Wolf, the, in Alps, 126.
+
+
+    Zones of climate on the earth, 63.
+
+Transcriber's note:
+    A "List of Illustrations II" has been added to the text, for the
+    convenience of the reader, to display Illustrations that were
+    not included in the original "Illustrations" section. The original
+    spelling of words, especially for place names, has been retained.
+
+
+
+
+
+End of Project Gutenberg's The Story of the Hills, by H. N. Hutchinson
+
+*** END OF THE PROJECT GUTENBERG EBOOK 43826 ***