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diff --git a/old/56303-0.txt b/old/56303-0.txt deleted file mode 100644 index 2f61454..0000000 --- a/old/56303-0.txt +++ /dev/null @@ -1,3353 +0,0 @@ -The Project Gutenberg EBook of Agate Fossil Beds National Monument, -Nebraska, by United States National Park Service - -This eBook is for the use of anyone anywhere in the United States and most -other parts of the world at no cost and with almost no restrictions -whatsoever. You may copy it, give it away or re-use it under the terms of -the Project Gutenberg License included with this eBook or online at -www.gutenberg.org. If you are not located in the United States, you'll have -to check the laws of the country where you are located before using this ebook. - -Title: Agate Fossil Beds National Monument, Nebraska - -Author: United States National Park Service - -Release Date: January 4, 2018 [EBook #56303] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK AGATE FOSSIL BEDS NATIONAL MONUMENT *** - - - - -Produced by Stephen Hutcheson and the Online Distributed -Proofreading Team at http://www.pgdp.net - - - - - - - - - - Agate Fossil Beds - - - Agate Fossil Beds National Monument - Nebraska - - Produced by the - Division of Publications - Harpers Ferry Center - National Park Service - - U.S. Department of the Interior - Washington, D.C. - - - The National Park Handbook Series - -National Park Handbooks, compact introductions to the great natural and -historic places administered by the National Park Service, are designed -to promote understanding and enjoyment of the parks. Each is intended to -be informative reading and a useful guide before, during, and after a -park visit. More than 100 titles are in print. This is Handbook 107. You -may purchase the handbooks through the mail by writing to Superintendent -of Documents, U.S. Government Printing Office, Washington DC 20402. - - - About This Book - -What was life like in North America 20 million years ago? Agate Fossil -Beds provides a glimpse of that time, long before the arrival of man, -when now-extinct creatures roamed the land which we know today as -Nebraska. Part 1 of this handbook introduces you to the park; Part 2 -brings life to the fossil specimens and examines the area’s geological -and ecological evidence; and Part 3 presents concise guide and reference -information. - - - Library of Congress Cataloging in Publication Data - - - United States. National Park Service. - Agate Fossil Beds National Monument, Nebraska. - (National park handbook; 107) Bibliography: p. - Includes index. - Supt. of Docs. no. I29.9/5:107 - 1. Vertebrates, Fossil. - 2. Paleontology—Miocene. - 3. Paleontology—Nebraska—Agate Fossil Beds National Monument. - 4. Natural history—Nebraska—Agate Fossil Beds National Monument. - 5. Agate Fossil Beds National Monument, Neb. - I. Title. - II. Series: United States. National Park Service. Handbook—National - Park Service; 107. - QE841.U59 1980 566′.09782′99 80-607119 - - - Contents - - Part 1 Welcome to Agate Fossil Beds 4 - Worlds of Past and Present 7 - Part 2 A Landscape Rich With Life 18 - _Text: James R. and Laurie J. Macdonald_ - _Illustrations: Jay H. Matternes_ - A Visit to the Past 23 - The Mark of Death Upon the Land 35 - The Geologic History of Agate 47 - Ecology: Change and Adaptation 53 - Part 3 Guide and Adviser 74 - Contents for this section 77 - - - - - 1 Welcome to Agate Fossil Beds - - - [Illustration: James H. Cook examines a fossil fragment at the - quarries near Agate Springs Ranch about 1918.] - - [Illustration: Besides fossils, Cook also collected Indian artifacts - and kept many of them on the walls of his study in the ranch house.] - - - Worlds of Past and Present - -Imagine that you are a healthy young man, raised conservatively in -Michigan several years after the end of the Civil War. You are a skilled -all-around hunter and trapper. The railroad has just spanned the -continent, and stories of the West, its dangers, its people, and its -opportunities come to you frequently. You and a friend decide you must -see this land for yourself, and you save your money carefully against -the day when you will be ready to go west. Around 1869, at age 12, that -day comes. - -At Fort Leavenworth, Kansas, you meet several cattlemen who tell you and -your friend where to get work as cattle herders. Before many years have -passed you have been a cowpuncher in Texas, you have fought Comanches, -and you have bossed a ranch crew for a wealthy Englishman. You go on to -fight the famous Apache Chieftain Geronimo as a scout with the U.S. -Cavalry, and you befriend a famous Sioux chief, Red Cloud. You marry, -buy a ranch in western Nebraska, and raise a family. And you become -something of a legend in your own time, your ranch known for its -hospitality to Indian, scientist, traveler—to one and all, rich or poor. - -A movie script? Not at all—these are the essentials of the life of James -H. Cook. Known as “Captain,” James Cook became the owner, in 1887, of -the Agate Springs Ranch, founded earlier by his father-in-law. Under -Cook’s watchful eye, the ranch prospered and became a second home both -for the Oglala Sioux and for paleontologists bent on excavating the -fossilized remains of the life of 20 million years ago, found here along -the Niobrara River in western Nebraska. - -This land, now encompassing Agate Fossil Beds National Monument, is -punctuated with low bluffs ascending westward toward the Rockies. It is -a land of sharp contrasts, of cool, inviting riverbanks and parched -ridges, the most famous of which are the fossil-bearing Carnegie and -University Hills. The surrounding grassy plains are a tapestry of wild -grasses—prairie sandreed, blue grama, little bluestem, and -needle-and-thread. The wildflowers lupine, spiderwort, western -wallflower, sunflower, and penstemon add touches of blue, purple, -orange, yellow, and red to the tapestry. In summer the dark green spears -of the small soapweed, a yucca, dot the brown grasses of the hillsides. -And just as they did more than 20 million years ago, cottonwoods and -willows provide shade and shelter for birds and other animals along the -river. - - [Illustration: Professor Othniel C. Marsh, back row center, of Yale - University and his students look as if they are equipped for a - frontier hunting expedition. But instead of looking for live animals - in the West, they were hunting for fossilized remains of ancient - beasts. Marsh and his crews made many such trips, and it was on one - early trip that Cook and Marsh met, in Sioux country.] - - [Illustration: Professor Marsh and the great Sioux chief Red Cloud - greet each other in New Haven in 1880.] - - [Illustration: Professor Edward Drinker Cope competed with Marsh for - the best fossils. He once made the mistake of reconstructing a - skeleton hind end foremost; Marsh never let him forget it.] - -Looking out over the rippling grasses, you grasp the fact that Nebraska -is larger than all of New England and feel the awesome spaciousness of -the Great Plains. The word “distance” has a different meaning here than -it does in the East. When James Cook came to the upper Niobrara River, -the closest town was Cheyenne, Wyoming—more than 160 kilometers (100 -miles) to the southwest. - -It was there, in Cheyenne, that Cook met Dr. Elisha B. Graham in 1879, -the year Graham selected this land for a cattle ranch as an investment -and as a summer retreat for his family. Graham named the place the 04 -Ranch, apparently because it is near the 104th meridian. Cook visited -the ranch often in the early 1880s and courted Elisha and Mary Graham’s -daughter Kate. They were married in 1886 and lived near Socorro, New -Mexico, for a year before returning to Nebraska with their newborn -child, Harold, and buying the ranch from Dr. Graham, who moved to -California. - -Cook began at once to make improvements to the ranch. He planted trees -by the hundreds and carried water to them faithfully to get them -started. As settlers failed to “prove up” their land claims over the -years, he added new lands to the ranch and changed the name to Agate -Springs Ranch in recognition of the native moss agates and the many -springs in the valley. He and Kate raised fine race horses as well as -cattle. - -The period in which the Cooks took over the ranch was one of transition -from the frontier days of migrations and Indian wars to more settled, -orderly lives. Ranching and farming became the dominant mode of life in -the eastern approaches to the Rockies. Even oil exploration played a -part in the development of the land. The transition was a difficult one -for many, Indian and settler alike. - -In some ways Kate Cook represented both the old and the new in Nebraska. -She was a fine horsewoman; one day she rode a bucking horse through the -streets of Cheyenne sidesaddle to win a bet for her husband. She was -refined, too, having taught herself French so she could read French -literature. Her mother, Mary Graham, became the first postmistress for -the small community around Agate. - -And James Cook was more than an adventuresome frontiersman. He was -actively interested in community and national affairs and in current -scientific questions. He became a patient, knowledgeable mediator -between the Indians and the settlers, and he was looked upon by the -Oglala Sioux as a friend and host, and sometimes employer. - -The Cooks became involved in a great scientific enterprise quite -accidentally around 1885, the year before their marriage. On a ride up -the conical buttes not far from the ranch house, a glitter under a rock -shelf caught Cook’s eye. They found fragments of bones scattered on the -ground. At first they assumed the bones were those of an Indian. But -Cook found instead “a beautifully petrified piece of the shaft of some -creature’s leg bone.” They carried it back to the house but didn’t -report the find until after they bought the ranch. Erwin Barbour of the -University of Nebraska was the first to respond to their reports and in -1892 became the first professional geologist to visit the area and do -some prospecting. - -The Cooks’ discovery thrust them and their ranch into a subtle battle in -the American West, a continuing struggle to find the best fossils with -which to reconstruct the ancient past. For centuries it had been thought -that life on our planet was only a few thousand years old, but by the -late 19th century science had evolved beyond that point of view. Now -paleontologists and their excavation teams were scouring the West in -search of fossils that might provide clues to the beginnings of life. - -The two most noted antagonists in this feverish search were Professors -Edward D. Cope of Philadelphia and Othniel C. Marsh of Yale University. -Cook knew them both, but the discoveries at Agate would wait for the -next generation of scientists. - - [Illustration: University Hill, left, and Carnegie Hill dominate the - Niobrara River Valley. The hills received their names from the - paleontological teams that worked them from the University of - Nebraska and the Carnegie Museum.] - -Cook had first met Marsh in 1874. Marsh had just arrived in Oglala Sioux -country to hunt fossils, but the Sioux Chief Red Cloud was suspicious. -Red Cloud was convinced Marsh and his men were just another party of -gold seekers. Cook, an able linguist, was then trailing cattle from -Texas to the northern railroads and reservations. He persuaded Red Cloud -that Marsh wanted only “stone bones” and averted a potentially -disastrous clash. This incident led to a lifelong friendship between -Cook and Red Cloud. And for Marsh this proved to be the last of many -expeditions as he relied on others to send him specimens from likely -fossil sites throughout the West. - - [Illustration: An upland sandpiper, one of many birds that can be - seen at Agate Fossil Beds, perches on a fence post.] - -Professor Cope and his crews often worked the same localities as Marsh. -Like Marsh, Cope tried to get the best specimens, and each occasionally -outbid the other for them, leaving bewildered farmers and ranchers to -puzzle over these men’s obsession with the past. Conflict also arose -over the naming of animals previously unknown to science. - -The hills of Agate Springs Ranch proved to be a rich archive of ancient -life. Dr. Barbour and his students confined their efforts to what soon -became known as University Hill. Thus began a quiet rivalry with Olaf -Peterson and his crew from the Carnegie Museum in Pittsburgh, -Pennsylvania, who worked what became known as Carnegie Hill. The most -numerous fossils these teams found at Agate are the remains of the -pony-sized rhinoceros _Menoceras_, but the site also is known for -fossils of the gazelle-like camel _Stenomylus_, the early small horse -_Miohippus_, and the corkscrew burrows of an ancient beaver, -_Palaeocastor_. - -Other distinguished scientists visited Agate over several decades. Among -them were Henry Fairfield Osborn and Albert Thompson of the American -Museum of Natural History in New York. The collections these men made at -Agate are still being studied and exhibited. - -James and Kate Cook’s older son Harold caught the fever, too. He became -a trained geologist and in 1910 married another geologist, Eleanor -Barbour, daughter of the distinguished Nebraska geologist. The new -generation of Cooks continued the tradition of hospitality and -scientific interest, encouraging further excavations of the fossil -treasures of Agate. Perhaps Harold Cook’s greatest moment of scientific -glory came in 1926, when he and other scientists participated in the -finds at Folsom, New Mexico, which proved to be a turning point in the -study of the human prehistory of North America. George McJunkin, a black -cowboy, had spotted the ribs of an animal protruding from the banks of -an arroyo. The Folsom spearpoint and the bones of an extinct form of -bison found there indicated that humans had lived on this continent for -more than 10,000 years, a startling revelation at that time though today -scientists put the figure at more than 40,000 years. - - [Illustration: Next to the fence stands a windmill, which once - provided water for excavation teams.] - - [Illustration: The narrow Niobrara River winds through the - surrounding tableland, carving out bluffs and exposing occasional - fossils.] - -In time the Cooks’ house became a repository for a substantial number of -Indian artifacts and natural history specimens. On summer weekends and -holidays tourists ventured out to the ranch to see the Cook Museum of -Natural History. James Cook personally guided many through the -collection, but usually the whole family participated, leading the -curious through three rooms and a small hallway. - -Harold Cook wanted Agate Springs Ranch to provide an enduring memorial -to the ancient past. Soon after his death in 1962 his second wife, -Margaret Crozier Cook, and friends began a campaign to add the fossil -beds to the National Park System. Their efforts succeeded in 1965, when -Congress authorized the establishment of Agate Fossil Beds National -Monument. - -Today you can walk about Carnegie and University Hills where the great -digs took place. You can see a few exposed fossil specimens, and you can -try to recreate in your mind the life and landscape of this part of -Nebraska 20 million years ago. To help you do that, we have asked -paleontologists James R. and Laurie J. Macdonald, in Part 2 of this -handbook, to take you on a journey to the past and then examine the -evidence. - - -Welcome to the worlds of past and present at Agate Fossil Beds National -Monument. - - - - - 2 A Landscape Rich With Life - - - _Text: James R. and Laurie J. Macdonald_ - _Illustrations: Jay H. Matternes_ - - [Illustration: This mural depicts life in the Agate Fossil Beds area - in the early Miocene Epoch, about 20 million years ago when the - story on the following pages takes place. The painting is a - composite of life at that time; if you had been there then, you - would not have been able to see all of these forms of life together - at any given moment! The original mural hangs in the fossil halls at - the Smithsonian Institution’s National Museum of Natural History in - Washington, D.C.] - - [Illustration: Key to mural] - - - 1/Moropus - 2/Promerycochoerus - 3/Menoceras - 4/Oxydactylus - 5/Daphoenodon - 6/Stenomylus - 7/Dinohyus - 8/Merychyus - 9/Palaeocastor - 10/Parahippus - 11/Syndyoceras - - - A Visit to the Past - -Come enter into our imaginations and return to a day along the Niobrara -River in western Nebraska 20 million years ago. Let’s go back and have -an imaginary look. To set the mood, think about the wild animal movies -made in modern Africa during the last 40 years. Think of a land swarming -with life, of extensive grasslands dotted with trees through which great -herds of grass- and leaf-eating animals are wandering. Look sharply into -the shadows under the trees and amid the high grass where the -meat-eaters are resting or stalking their prey. When you have this -picture of wildlife in mind we’re ready for our journey into the past. - -Projecting ourselves back those 20 millions of years, we find ourselves -in a landscape filled with animals. Some of the animals are not much -different from those living today, but others are so bizarre that you -may have a hard time believing they really existed. - -Dawn is building a new day, and those animals which hunt and feed at -night are disappearing into their lairs. There are so many kinds of -livings to be made that the day isn’t long enough for all animal -varieties to be about and active only in daylight. As the light spreads -over the land we see that it is an open, sunny place of mixed grasses -and trees—mostly grassland, but here and there single trees or small -clumps not big enough to be called groves. We would call it a savanna. - -A broad river runs through the land, and for lack of a better name we -can call it the Niobrara or “Running Water,” the name given by Indians -to the much smaller modern stream. This ancient Niobrara was a bold, -wide stream with deep pools and sandbars. It was not cutting a valley as -its modern counterpart is doing, but was carrying sand and silt down -from the then-young Rocky Mountains. It sometimes flooded, and as it -spread out over the wide, flat plain it deposited layers of sand and -silt that geologists today call the Harrison Formation. The ancient -Niobrara and other similar rivers spread the same sediments over nearby -areas in eastern Wyoming and southwestern South Dakota. In the -sediments, paleontologists would one day find millions of bones. - -Our ancient river was the center of life for untold numbers of animals. -They lived in it, along its banks, in the willow thickets that grew on -its more permanent sandbars, and on the broad, tree-dotted plains that -stretched to the horizon beyond the river’s normal course. Great herds -of small horses, rhinoceroses, camels, and other dwellers on the savanna -came to water holes to drink and perhaps to wallow in the cool and -refreshing pools. Although all else might be anticlimactic, let’s look -at the rhinoceroses first. - -We know that in the modern world rhinos belong in Africa and -southeastern Asia, not North America, yet this continent was the major -home of these strange beasts for millions of years. Rhinos did not -become extinct in North America until about 5 million years ago, during -the Pliocene (see geologic time chart on page 46). Along the ancient -Niobrara the rhino herds are not made up of the giant mammals we see in -zoos today. The ones we see moving slowly toward the river on this early -Miocene day are no larger than big domestic pigs. They are the first -among the rhinos to have horns—not one behind the other, but a pair near -the end of the nose, side by side. To scientists today these rhinos are -known as _Menoceras_. The name _Diceratherium_, once used both for these -small rhinos and a larger type of ancient rhino, now refers accurately -to just the large rhino. - - [Illustration: _Menoceras_] - -Look off to the south. There’s a herd moving slowly but purposefully -down to its favorite watering hole. You can see that the males have the -paired nose horns, and that the females, which are about the same size, -do not. Trotting amid the herd are fat little colts whose seriousness of -purpose belies their youth. The herd seems to be made up of about 50 -individuals moving through the tall grass like a flattened dark gray -cloud. Suddenly they are startled by a large cat or dog stalking through -the grass, and all the males on the side nearest the enemy bunch -together to face the hungry hunter. Most of the herd continues to flow -across the plain, and when the danger is past the guardian males catch -up in a lumbering gallop. - -Finally the herd reaches the river and spreads out through the shallows. -It is hot today, and the flies are biting even through the tough rhino -hides. Many of the adults go into deeper pools to roll and soak while -the young drop their serious attitudes and frolic in the shallows. - -As the day wears on, the herd leaves the river and feeds on the leaves -and stems of scattered trees and willow thickets along the river. When -twilight comes, the herd draws together, colts and females toward the -center and bulls around the edges. After a period of milling and -pushing, the herd finally beds down for the night, with only the -perimeter guards moving around on the edges. - -The daily routines of the other herds of grass- and leaf-eating animals -generally follow somewhat different patterns from that of the rhinos. Of -them, only the piglike oreodons wallow in the river. The others spend -nearly all their time out on the savanna, coming to the river only at -dawn or dusk to drink. - -Oreodons were among the most abundant medium-sized animals of the Middle -Tertiary. A strictly North American group, they have been described as -looking like a cross between a sheep and a pig. As small as a house cat -or as big as a domestic pig, these mammals reached a peak in abundance -and variety between the Middle and Late Oligocene (though they are known -from the Late Eocene through the Late Miocene). This peak probably has -never been equalled by any other group of mammals in such a size range. - -As we look out among the herds of animals dotting the plain, we can see -only a few small bands of oreodons. There’s a group coming toward us -now. These are some big, ugly ones with large triangular-shaped heads. -The backs of their cheek bones flare out far to the sides, so that with -their narrow snouts they are most peculiar looking. Their bodies are -long and rather nondescript, and their legs are short but slender. This -particular kind is known as _Promerycochoerus_ (“before ruminant hog”) -and is just about the largest of the oreodons. They are really a rare -sight here at Agate. Perhaps the large herds of _Menoceras_ fill their -ecologic niche locally, and the oreodons have found they cannot -successfully compete with the rhinos for food, water, and living space. -After all, not everything can fit into Paradise. - - [Illustration: _Promerycochoerus_] - -Look to the northeast: there’s a herd of _Miohippus_ (“Miocene horse”) -wading into the river to drink and browse in the willows along its -banks. Let’s walk toward the herd slowly and quietly. We should take an -especially good look at this herd—they are part of a doomed race! The -genus _Miohippus_ is making its last stand at this time. When conditions -change, well adapted species may restrict their ranges to what is left -of the old environment; they may adapt, if they are able, to the new -conditions; or they may not survive if they cannot adapt. - -_Miohippus_ did all these things. Some species of the genus became -extinct. Some evolved into something else. But the end result was the -complete termination of the genus _Miohippus_ as paleontologists -recognize it. Much of the environmental pressure coming to bear on the -genus _Miohippus_ was a result of mountain building to the west. As the -young Rockies rose, rain-bearing winds from the oceans far to the west -were wrung of their moisture. This same circumstance makes the high -plains a land of little rain today. - -The scattered trees and groves we see from our vantage point of long ago -will disappear and be replaced with a sea of drought-tolerant grasses. -In effect, the savannas will give way to prairies. _Miohippus_ will soon -be yielding its place to descendants which can eat grass as a steady -diet. Grass is much harsher on the teeth than the foliage that -_Miohippus_ eats. In eating grass, grazing animals pick up sand and silt -enough to quickly wear away teeth designed for leaf-eating. The -descendants of _Miohippus_ will become better runners, too, with longer -and more powerful legs. As the trees disappear there will no longer be -friendly clumps of greenery to hide behind when hungry meat-eaters are -on the prowl. From now on, fleetness of foot will be a most important -factor in horse survival. - -_Miohippus_ will also give rise to somewhat larger forest horses that -will survive on into the Pliocene in patches of woodland. They will be -little changed except in size (some came to be nearly as large as the -modern horse), and some of them will even cross the Bering Land Bridge -into Eurasia. This is the last time, however, that we’ll see these -primitive horses in large numbers here in North America. - -There’s another herd of small horses moving across the plain toward the -river from the south. These are feeding as they move across the savanna, -eating both leaves from the scattered trees and grass from the prairie. -They seem to be enjoying their mixed diet and thriving on it, so they -won’t be too badly hurt in the geologically near future when they have -to eat mostly grass. This is _Parahippus_ (“near horse”), a new kind of -horse just recently evolved from _Miohippus_. - - [Illustration: _Parahippus_] - -_Parahippus_ is a horse of destiny. For a long time some individuals of -_Miohippus_ carried a little extra wrinkle of enamel on the crowns of -their upper grinding teeth—and now the wrinkle occurs in all individuals -of _Parahippus_. Because of it, _Parahippus_ can eat grass without -wearing out its teeth before reaching breeding age, making it possible -for most individuals to reproduce before dying. The little wrinkle is -passed on. It’s only a small advantage, but such is the stuff that -survival and evolution are made of. _Parahippus_ is the forerunner of a -vast array of different three-toed, long-limbed prairie horses that will -be the most numerous members of their family until nearly the end of the -Pliocene. From one of their descendants will come the first one-toed -horse—the direct ancestor of our modern horses. - -More herds are moving in on the river as the morning grows. There’s a -group of something very small moving through the tall grass, but it’s -completely hidden. Only the swaying of the 60-centimeter-tall blades -shows that a number of animals are hurrying toward the river. Now -they’ve moved out into an area of cropped grass, and we can see a herd -of the diminutive deerlike _Nanotragulus_ (“dwarf goat”). Not a great -deal larger than a house cat, these little “deer” have tall grinding -teeth well adapted for grass-eating. Their ancestry goes back for -millions of years into the Late Eocene, when some of their ancestors -stood less than 15 centimeters (6 inches) high at the shoulder. But -their entire family is soon to become extinct. They are part of the -grazing community, although they eat leaves and softer vegetation just -as readily. We call them “deer” because they look just like miniature -deer, but the two families are really only distantly related. - -As this group scampers toward the river, we can see that they have a -peculiar crouching gait—their forelegs are so much shorter than their -hind legs that they seem to be running continuously downhill. They are -dainty little animals with small, delicate heads and short, slender -limbs. They can bound swiftly away if danger threatens, but they’d -rather hide in the thick brush. A few of the females have fawns with -them, tiny things less than 10 centimeters (4 inches) tall. Look at them -all scatter! The shadow of a hawk has passed over the group, and in -their fright they’ve dived for some nearby willows. Young _Nanotragulus_ -either learn to duck down at the sight of a passing shadow or they don’t -get a chance to learn at all. This time they all got away, and the hawk -will have to look elsewhere for a meal. - -Buteos or buzzard hawks are common along the Niobrara in the Early -Miocene, sailing on the warm updrafts on broad, short wings that let -them ride the lightest airs. They swoop down on the mice and pocket -gophers, young rabbits and beavers, baby “deer” and sometimes careless -birds that live on this savanna. All manner of meat-eaters depend on the -small animals for food, and the little _Nanotragulus_ are most -vulnerable as they move through the canopy of grass. - -There don’t seem to be any other herds moving into view just now; but -while we’re on the subject of birds, over there in that patch of short -grass is a bird rarely seen in North America anymore. It’s a guan, a -ground-living bird related to the grouse and sagehens. It must be far -from home this morning; most of its time is spent in the thick brush -farther back from the river. A heavy body and long neck and tail make -this animal easy to identify. - - [Illustration: _Oxydactylus_] - -Let’s look at some of the individuals and small groups that are moving -or resting within view. The camels with the very slender legs and long -necks are called _Oxydactylus_ (“sharp finger”). They are browsing on -the willows where the herd of Nanotragulus ran to hide. _Oxydactylus_ is -an important camel, standing about at the midpoint in the evolution of -this North American family of mammals. The camels will remain -stay-at-homes in the continent of their origin until they spread into -Eurasia and South America at the beginning of the Pleistocene Epoch, -some 17.5 million years after the rhinos died out at Agate. There are -many species of _Oxydactylus_; the one we are looking at stands about -1.2 meters (4 feet) high at the shoulder. Notice that they don’t have -humps on their backs; in this lush land there is no need to store fat -against a time of possible starvation. - - [Illustration: _Stenomylus_] - -Speaking of camels, here comes a herd of _Stenomylus_ (“narrow tooth”) -bounding through the tall grass on the south bank of the river. This is -a strange little long-neck camel that strayed off the main line of the -family’s evolution. Less than 60 centimeters (24 inches) high at the -shoulder, it looks very much like the living African antelope called the -gerenuk. _Stenomylus_, with its long and delicate legs and tall -cheek-teeth, is perfectly adapted for living in and eating the abundant -grass which billows on this tree-dotted plain. Yet many of the little -_Stenomylus_ are going to share a tragic time with hundreds of -_Menoceras_ only a year or so from this day we are visiting. Later, -we’ll move ahead to that time so you can see that natural disaster, now -preserved in rock, as it happened. - -When you travel back 20 million years in time you would expect to find -unbelievably bizarre animals. So far, we’ve seen some offbeat specimens, -but there has been nothing really out of this world. Now, if you look to -the north by the lone oak tree, you will see a real prize. Do you see -that hulk stepping out of the shade? No, it isn’t the Dragon of the -Ishtar Gate, though it might pass for a mythical beast. What a wonderful -animal! A head like a large horse’s, a neck somewhat slimmer, long front -legs, sloping back, short hind legs, and a little switch tail. Watch -with your field glasses when it moves out onto the bare ground. See the -feet? They don’t have hooves; each toe ends in a great curved claw! This -is one of the fabulous chalicotheres, a relative of the horses and the -rhinos. There were never very many of them living at one time, but the -family lived in Eurasia from the Eocene, some 55 million years ago, -through the Pleistocene; and here in North America from the Late Eocene -to the Middle Miocene. - - [Illustration: _Moropus_] - -This chalicothere is named _Moropus_ (“sloth foot”), and it is little -wonder that when paleontologists first discovered his foot bones -(without an associated skull) they thought they had found the feet of a -ground sloth. Let’s watch _Moropus_ as it ambles slowly across the -plain, its strange stilted walk a little like that of the modern -giraffe. Other animals move aside as _Moropus_ strides through the -grass. He’s a browser, an occasional grass-eater, and even a digger of -easily accessible roots and tubers. Like his cousins the rhinos, he -isn’t at all bright, and he has a very short temper. When he’s annoyed, -he kicks out with those claws and every animal with good sense leaves -him alone. He’s respected by meat-eaters and plant-eaters alike. He -walks by himself and everything else detours around him. - - [Illustration: _Dinohyus_] - -Look down toward the river, and we may see an exception. That two-meter -(six-foot) high “pig” walking away from the river, covered with mud, is -heading right toward the _Moropus_. His name is _Dinohyus_ (“terrible -pig”), and he’s just as short-tempered and stupid as _Moropus_. He looks -like a giant peccary, but his size and over-large head give him away as -an entelodont (“complete tooth”). These are pig-like animals, usually of -large size, that aren’t related to the domestic pigs at all. _Dinohyus’_ -skull is nearly one meter (three feet) long, and those tusks are as -thick as a man’s wrist. Though we missed seeing him earlier, he must -have been wallowing in the mud under the overhanging willows. Now he’s -heading away from the river in search of lunch. He’s not very choosy -about what he eats; it might be succulent leaves or fruits, or even the -carcass of a dead animal. _Dinohyus_ is an omnivore, eating almost -anything that has nourishment. - -Right now it looks as though he’s on a collision course with the -_Moropus_. He’s seen the larger animal, has stopped in his tracks, and -is pawing the ground with his front feet. Up goes his head—and listen to -that roar! He’s getting a good temper worked up. Off he goes at a full -gallop, right toward the _Moropus_. It’s hard to believe that an animal -as big as that pig could charge so fast. And look at the _Moropus_! He’s -finally realized in his dim way that he’s about to be attacked. Up he -goes on his hind legs, holding his front legs out ready for a downward -blow with all eight claws. But suddenly _Dinohyus_ shifts his course -just slightly, lets out another loud bellow as he avoids the _Moropus_, -and thunders off toward the open prairie. - -_Dinohyus_ has a smaller relative around here somewhere, a little fellow -just over one meter (three feet) high, called _Entelodon_. His head is -long and low and has flaring cheekbones and bumps along the underside of -the jaw like his larger cousin’s. Another pig that lives along the -Niobrara is _Desmathyus_ (“bond [filling a gap] pig”), a true North -American pig or peccary. Its appearance probably wouldn’t surprise -anyone; it looks very much like the peccaries that live in the American -Southwest today. Its distant cousin, the domestic pig, was domesticated -in the Old World from a European species of wild hog, and it was spread -throughout the world by European colonists. In America, peccary -evolution has run a long and conservative path. This group has changed -relatively little in the 35 million years since it first appeared in the -Late Eocene. - - [Illustration: _Syndyoceras_] - -Now for another weird and wonderful beast! Trotting daintily out of a -thicket on our left is a herd of something you might think were deer or -pronghorn. But if you look closely you’ll see that they have two pairs -of curving, unbranched horns on their heads, not the single pair of -prongs you’d expect on a pronghorn. These are _Syndyoceras_ (“together -horn”), members of a family of mammals found only in North America and -now extinct. Even on the Early Miocene day we’re visiting, they are -scarce, moving only in small herds. The rear pair of horns is not -remarkable, but the front ones, which rise from a large bump near the -nose, curl up and away from each other, ending in blunt tips. - -The first member of this family was _Protoceras_, which lived in the -hills and mountains of western South Dakota during the Late Oligocene, -just a few million years before the day we are visiting at Agate. -Paleontologists have found battered scraps of its skeletons in the White -River Badlands where perhaps they were washed by heavy spring rains -running off the hills to the west. _Protoceras_ had six bony bumps on -its head that presumably bore short horns; one pair was over the nose, -another was over the eyes, and a third was near the back of the skull. -Probably it was the direct ancestor of _Syndyoceras_. - -If _Syndyoceras_ fails somehow to qualify as grotesque, let’s jump a few -million years into the “future” and look at his Late Miocene descendant, -_Synthetoceras_ (“combined horn”). Here was an animal on a par with -unicorns and cyclopses. Like _Syndyoceras_ he had two tall horns at the -back of his head; but something had happened to the curved ones on his -nose. They had, during several million years of evolution, grown -together into a single shaft and then spread out again to the sides and -up. What a pity there were no little boys then, for here we have the -world’s first and only self-propelled slingshot! Tie a rubber band to -the tips of his nose horns, fill your pocket with pebbles, and saddle -up. - -You may be wondering by now about the smaller animals—the rodents and -small carnivores. We have not seen any of them so far. Most carnivores -work at night, but there should be a few about. Down by the river is a -pair of _Oligobunis_ (“little cusp”) hunting near the water’s edge. They -look something like modern badgers but are really more closely related -to the weasels. If you look just to the right of the herd of -_Stenomylus_ we were following earlier you might be able to catch a -glimpse of a stalking cat about the size of a mountain lion. It’s -probably either an advanced _Nimravus_ (“ancestral hunter”) or an early -_Pseudaelurus_ (“false cat”), but we’ll have to get a closer look before -we can be sure. Whichever it is, it’s on the main line of cat evolution -and will eventually end up in our familiar _Felis_ and the other living -cats. There should also be some sabretooth cats lurking about; they are -found in nearby deposits of the same age, though not at Agate itself. - - [Illustration: _Daphoenodon_] - -If you look very closely at the thicket just south of us on the hillside -you can see several fox-like dogs hunting rodents. This _Nothocyon_ -(“false dog”) seems to have filled approximately the fox niche during -the Early Miocene. Some coyote and wolf-sized dogs are in the area too. -_Daphoenodon_ (“blood-reeking tooth”) is about coyote size. _Temnocyon_ -(“cutting [tooth] dog”), is a little larger, probably substituted for -the wolf in the local fauna, and is characterized by its heavy head and -long, strong jaws. If we could get a close look at its teeth, we would -see that they are like those of the Cape Hunting Dog living today in -South Africa. - -Let’s move away from the river a half-kilometer (0.3 mile) or so and see -if we can find something different. That thicket ahead might produce a -couple of rabbits. Look, there at the edge of the thicket: a _Nothocyon_ -has caught something. It’s a _Meniscomys_ (“crescent mouse”), an early -relative of the living mountain beaver _Aplodontia_. Today, a single -species of _Aplodontia_, the last of the line, is found only in the -mountains of the West Coast. It’s the most primitive living rodent, not -related to the Canadian beaver, and sole survivor of a suborder which -was the earliest rodent group to evolve. _Meniscomys_ was one of the -most prominent members of the group during the Miocene. It had a round -furry body, a round head with protruding incisors a bit like a true -beaver’s, and no visible tail. - -Watch your step. There is the mound of a pocket gopher. It is neither -our familiar western gopher _Thomomys_ (“heap mouse”) or the “eastern” -pocket gopher of the Great Plains, _Geomys_ (“earth mouse”), but an -ancient relative, _Gregorymys_ (“Gregory’s mouse”). It must be pretty -successful as a burrowing animal, because we find it all over the -western United States in the Early Miocene. - - [Illustration: _Palaeocastor_] - -A hundred meters (300 feet) more and we’ll show you the surprise of the -day. Here we are in what looks like a prairie dog town. But those aren’t -prairie dogs. They’re a little larger, and quite unfamiliar by modern -standards. Can’t guess what they are? These are beavers—_Palaeocastor_ -(“ancient beaver”) to be exact. Here in the Early Miocene of North -America, beavers don’t build dams. In fact they live neither at the -water’s edge nor, like muskrats, in the water. They dig deep, spiral -burrows in well drained ground. Some of their burrows are 2.5 meters (8 -feet) deep, but 2 meters (6.5 feet) is about average. Down and around -and around the burrows go, like giant corkscrews, always ending in -straight shafts slanting slightly upward so that living chambers will -not be flooded by rainwater running down the burrows. - -Paleontologists have called the preserved burrows “devil’s -corkscrews”—_Daemonelix_—since the time they were first found. At first, -scientists thought they might be holes left by the giant tap roots of -some unknown plant. But when _Palaeocastor_ skeletons were found in the -bottoms of the spirals, almost everyone had to concede that they were -truly beaver burrows. Admittedly, the skeleton of a _Nothocyon_ was -found in one burrow; but this predator probably followed a beaver home -for supper and just stayed. Three other kinds of beavers lived around -Agate in the Early Miocene, but their bones have never been found in the -burrows. No one knows what they did for homes: perhaps their burrows -were much shallower or were in the river banks where running water soon -destroyed them. - -Near the river bank in some soft sand is a nest of tortoise eggs. The -hot sun has brought the babies out of their shells and they’re stumbling -off in all directions. Right now the biggest is only about twice the -size of a silver dollar; but when they’re grown they’ll be about 60 -centimeters (24 inches) across the shell, or perhaps even larger. -They’re strict vegetarians, grazing and browsing on soft plants and -leaves. There are probably some pond turtles around too, but we’ve never -seen any. - -A little farther up the bank, under the roots of that big walnut tree, -is a rabbit’s burrow. Several _Palaeolagus_ (“ancient rabbit”) live -there with their many offspring. Although they look very much like -cottontails, their ears are smaller and they haven’t the same leaping -and running ability. They’d much rather hide than flee their enemies. - - -These dwellers of the savanna, common during the Miocene Epoch, comprise -the major species found at the Agate Fossil Beds. Their discovery in the -late 1800’s and early 1900’s was highly important to the young science -of paleontology. In those decades of major discoveries, large gaps -remained in the story of evolution. Quarries like those at Agate helped -provide the missing pieces of the puzzle. In their time, the discoveries -at Agate were an important contribution toward understanding the world -far beyond the dawn of mankind. - -Today, advances in paleontology still depend primarily upon major field -discoveries, but paleontologists also make use of highly refined -analytical and measurement techniques. Closely connected with -paleontology are several other sciences, among them geology, zoology, -and botany. The paleontologist, for example, must depend on geology to -provide important answers about the age of fossil specimens. Fossil -botanical specimens, in turn, can provide answers about animal diets and -climate. Though paleontology may center on the study of fossil remains, -it is an interdisciplinary science. This fact will become increasingly -apparent in the following chapters, which reveal the strands of evidence -used in constructing the picture of Miocene Agate. - - - The Mark of Death Upon the Land - -Even in Paradise an occasional calamity can occur. Agate’s misfortune -appeared in the form of a drought. To the west of the plain built by the -ancient Niobrara River, the Rocky Mountains began to rise again. This -renewed uplift, after millions of years of relative quiet, eventually -led to an even drier climate and a replacement of the savanna with a -landscape of unbroken grasslands from the mountains to the Mississippi -River and beyond. Trees then could survive only on canyon slopes along -the courses of the few large remaining rivers that crossed the plains. -Those rivers flowed toward the central lowlands of North America, once -an embayment of the Gulf of Mexico. This Mississippi Embayment, as it is -called by geologists, extended as far north as the present location of -Cairo, Illinois. - -During the first rumbles of this upheaval there were occasional -instabilities in the weather of the Great Plains. From the fossil -evidence of Carnegie Hill, University Hill, and the _Stenomylus_ quarry, -we can see that drought touched the land. - -What happens when disaster stalks the land? That question, so pertinent -to an understanding of fossil deposition at Agate, can be answered best -by looking at the normal scheme of life. Animal populations are cyclic, -increasing rapidly to near the highest numbers which can be supported on -available food supplies. If times are good, animal populations can be -quite high. If the food supply decreases, massive dieoffs result. -Successive cycles of plenty and poverty then produce high populations -followed by dieoffs. - -The fossil evidence suggests that a prolonged drought occurred during -the Golden Age at Agate, resulting in death everywhere. The vast numbers -of rhino skeletons preserved at Carnegie Hill and University Hill -provide paleontological evidence that the drought must have lasted for -several years. - -Climates change slowly, and there are wet and dry cycles. Every rancher -and farmer discovers this when he plows new land during a wet cycle, for -sooner or later drier years catch up with him. He expects the optimum to -be the standard; but he is badly hurt during average times, and really -suffers when the dry years come. It is the same with populations of wild -animals. When the times are good and the grass and trees are lush, fat, -and green, more of the young survive and the whole population -flourishes. The plant-eaters expand their herds and the meat-eaters -increase to keep up with the better food supply the plant-eaters -provide. In each case the standards for survival are lowered, and the -less than perfect can survive and in turn produce young of their own. -But when the water fails and plants refuse to grow, the herbivores -starve and the carnivore population in turn declines. Nature is -indifferent—neither cruel nor kind. When times are bad every species is -improved, for the strongest and most tenacious survive to reproduce -themselves. There are benefits to hardship. - -So it was at Agate only a year or so after the day of our visit. The -river died for a while. As with many rivers much of its water flowed -beneath the surface, through the sand and gravel of the bed. When the -ancient Niobrara died there was still water moving through the sands and -filling the low spots in its bed. Some animals could dig down to it and -survive, others could stake claims to the diminishing water holes. So -the thirsty, suffering herds of _Menoceras_ went to the river and found -no water. The strong held the water holes. The smart dug into the sand -and made their own water holes. The rest died. They died by the -hundreds, and thousands. Mixed with the carcasses of _Menoceras_ were -other victims: occasional chalicotheres, giant pigs, oreodons, cats, -dogs, and a variety of equally thirsty smaller animals. Perhaps most of -the animals went farther up or down stream, or perhaps they chose not to -die at the river. Whatever the pattern of dying might have been, we know -that _Menoceras_ left untold numbers of skeletons on the broad, flat, -and dry bottom of the ancient Niobrara. - -Finally the rains fell in the mountains to the west. The river filled -with water again and ran in sheets across the plain. At Agate the -millions of _Menoceras_ bones and lesser numbers of the bones of other -animals were swept for a few hundred meters downstream and into some -sort of backwater or river lake—possibly a great meander, or an oxbow -lake. There, like a gigantic mass of jackstraws, they were piled in a -tangled mat 30 centimeters (12 inches) thick, covering an unknown number -of hectares. All we really know is that they were moved far enough to -get thoroughly jumbled, but not far enough to be badly broken or much -eroded by the action of the water. - -The mass of bones was soon buried by the sands and silts dropped by the -reborn river, and by wind-carried debris swept off the parched land. -Once buried, the bones were partially petrified by mineral water flowing -beneath the surface. The land was built up a few hundred meters by -sediments continually brought down from the mountains to the west. -Eventually, continued uplifts of the Rockies and the Great Plains -combined with erosional cycles to leave the modern Niobrara River. The -two erosional remnants known today as Carnegie and University Hills were -produced by the cutting of the modern river system. On the sides of -these hills were exposed the tangle of bones which marked the site of -ancient tragedy. - -But this wasn’t the only scene of mass death to be preserved here in the -fossil record. A few kilometers away an earlier drought took a toll of -many other animals. The little gazelle-like camel _Stenomylus_ tells the -same story in scores of skeletons east of the _Menoceras_ burial ground. - -These graceful little camels may have died at the edges of their -vanished water hole. The skeletons are mostly undisturbed except for a -few pulled apart by meat-eaters. Scores of their dried out, mummified -carcasses were buried about the same time as the rhinos on the river’s -dry bottom. Like the _Menoceras_, the camels lay there for millions of -years, intact in their death poses, the muscles in the backs of their -necks pulling their heads back sharply into an unnatural position. There -they lay until men discovered them. - -Our imaginary journey into the past has reached its end. We have seen a -day at Agate as it might have been 20 million years ago. We have watched -the animals going about their daily lives during times of plenty and -have seen it as it was later, when death’s heavy hand left a magnificent -fossil heritage. This unique place is a window into the past, a window -through which we can look back at any time and observe life at Agate -millions of years ago. - - - Excavations at Agate Springs - - The first fossils were collected in volume in 1904 by Olaf Peterson of - the Carnegie Museum in Pittsburgh. Excavations have continued, off and - on, to the present. As early as 1892, Erwin Barbour’s student F. C. - Kenyon had retrieved a few bones from the site but their significance - was overlooked. Rancher James Cook first picked some up in the 1880s - and may have first noticed such deposits, without particularly - recognizing them, in the 1870s. - - Other institutions soon joined Carnegie in extracting slabs of the - great _Menoceras_ bone-bed, and occasional _Moropus_ and _Dinohyus_ - specimens. The University of Nebraska opened a new quarry in 1905. - Henry Fairfield Osborn, president of the American Museum of Natural - History and one of the greatest popularizers and exponents of - evolutionary science, and his chief preparator Albert Thomson began - work in 1907. F. B. Loomis of Amherst College discovered the nearby - _Stenomylus_ quarry the same year. Yale University’s R. S. Lull soon - followed. - - From 1911 to 1923 the American Museum became the main excavator at - Agate, but increasingly their attention was drawn elsewhere, including - the later Miocene Snake Creek Beds 20 miles to the south. There, for - awhile, great excitement centered around a worn tooth thought to be - from an early human ancestor until the tooth was proven to be from an - ancient peccary. - - Until 1981, only occasional excavations for bonebed slabs and - _Stenomylus_ marked the next 50 years. Then, Robert M. Hunt Jr. of the - University of Nebraska reopened the main quarries and a little-known - side area, and found evidence of an extensive carnivore den of the - beardog _Daphoenodon_. - - In some cases, individual fossil bones were removed one by one, a very - slow and painstaking process but when possible large blocks of - fossil-bearing sediments were removed and shipped to laboratories for - cleaning and analysis. The tools, chemicals, and special conditions - necessary to extract the best specimens and most complete information - are available only in a laboratory such as the one which is shown on - pages 40 and 41 at the Carnegie Museum in Pittsburgh, Pennsylvania, in - 1905. Slabs from Agate Fossil Beds were taken there so paleontologists - could examine the evidence and figure out the past. - - See pages 86-87 for a listing of museums with specimens from Agate - Fossil Beds. - - [Illustration: Extracting a slab] - - [Illustration: Members of Peterson’s crew built a box around a slab - in the _Stenomylus_ quarry around 1908 in preparation for shipping - to the Carnegie Museum.] - - [Illustration: With a team of horses, O. A. Peterson’s field crew - moves dirt out of the _Stenomylus_ quarry around 1908. The boxes in - the foreground are resting on the quarry’s lower bone layer. Several - specimens to the left have been strengthened with plaster for - shipment to Pittsburgh.] - - [Illustration: Crates of prepared specimens had to be taken to - Harrison, 37 kilometers (23 miles) north of Agate for the rail trip - to the East. Note that the wagon is just a flat platform and that - the driver is using the largest crate as a seat.] - - [Illustration: Paleological laboratory.] - - - The Beginnings of Paleontology - - Paleontology is the study of ancient life through the fossil remains - of that life. Today, there are thousands of museums, societies, - professional groups, and academic institutions around the world - devoted to this study. Fossil remains are still being dug out of the - ground in a number of localities, such as Dinosaur National Monument - in Utah, but by far the great bulk of fossils now being studied were - excavated during the last 100 years. - - There are now about 250,000 known separate species of fossil plants - and animals. Biologists are still working to explore, find, and - classify all living species; they estimate that 4,500,000 species of - plants and animals are now living at our own brief moment in the - nearly five billion years of our planet’s history. As you can see, the - fossils now known represent only a tiny fraction of all the plants and - animals that have ever lived. Yet a great deal is now known about even - the simple forms of life more than three billion years ago. - - How has this come about? What has happened since the days of our - great-grandfathers to cause this vast increase in knowledge? Men must - have picked up and discussed fossils for tens or perhaps hundreds of - thousands of years. We have no way of knowing what the earliest men - thought about them. Their significance has been revealed slowly in the - way we tend to look at time, but perhaps not so slowly when we - consider how short a period man himself has been on Earth. - - Lucretius, a Roman writer of the first century B.C., thought that the - Earth was very young. He interpreted the fossils known to him as the - remains of monsters that had grown out of the Earth just after it came - into existence. Evidently he had seen partial fossils and believed - them to be whole, because he postulated that the Earth had brought - forth creatures that lacked one or more limbs or other body parts. - Lucretius assumed, as have many others, that the varieties of animals - he knew of were fixed for all time and did not change. But he did - recognize the principle of evolution, that things change as time goes - on, in his description of human history. - - Lucretius described four ages of human life, progressing from early - hunters up to the highly civilized life he knew under the Roman - Republic. His work was rediscovered during the European Renaissance, - when scholars once again began to inquire into the nature of seemingly - inexplicable things like fossils. - - Toward the end of the 18th century the confusion over the importance - of fossils and their relative antiquity forced a scientific showdown. - For hundreds of years, fossil bones of extinct animals unlike any ever - seen had been turning up, often with tools nearby that appeared to - have been shaped by human hands. A growing feeling that the Earth and - therefore the fossils were very old indeed was a topic of frequent - discussion in Europe and in the New World, despite the assertion by - Archbishop Ussher a century earlier that the Earth was not quite 6,000 - years old. - - Explorers and scientists had found fossils in deep layers of rock - widely separated by other layers of rock, leading many of them to - conclude that now-extinct forms of life had existed before the - Biblical flood. A pioneer French paleontologist, Georges Cuvier, tried - to solve this dilemma in the late 1700s by postulating that there must - have been several worldwide floods before the one described in the - Christian Bible. Finally, this solution collapsed under the weight of - new evidence as more and more studies proceeded. - - In the 1830s an English geologist, Sir Charles Lyell, popularized the - principle of uniformitarianism—the idea that processes we observe now, - such as the steady erosion of mountains, the gradual buildup of silt - as sediments in rivers, lakes, and oceans, have always occurred since - the origin of the Earth. This, he then reasoned, meant that the Earth - must be many millions of years old at least, instead of merely a few - thousand years old. - - A wave of interest in fossils and their antiquity swept communities - around the world in the 1840s and 1850s. Americans interested in - science from Thomas Jefferson on had advocated the collection and - study of fossils, and a feverish race to build up study collections - got underway that lasted into the 20th century. Today, scientists - believe the Earth is more than 4.5 billion years old, its life more - than 3 billion years old. - - [Illustration: Karl Von Linné, 1707-1778, is known as Linnaeus after - the Latin form of his name. A Swedish botanist, he established a - hierarchical system for classifying plants and animals that is still - in use in a modified form. His organizing principle was the degree - of complexity of the organisms he studied. This resulted in a system - with seven levels: Kingdom, Phylum, Class, Order, Family, Genus, and - Species, in descending order from the broadest category to the most - specific. Students remember the system by the sentence “King Philip - Crossed the Ocean For Good Soup.” Without realizing it, Linnaeus - prepared the ground for the evolutionists, who later were able to - demonstrate the gradual ascent of life forms from simple to complex - by using his scheme of classification.] - - [Illustration: Jean-Baptiste de Lamarck, 1744-1829, a French - physician and ex-military man, founded the modern study of animals - without backbones and coined the term invertebrates to describe them - as a group. When his battle wounds forced him to take up a new - career, he studied botany and published a study of French plants. He - later turned to invertebrates, and between 1815 and 1822 published - the classic _Histoire naturelle des animaux sans vertèbres_. He - applied his vast knowledge of living invertebrates to - paleontological work, greatly enhancing the knowledge of fossil - invertebrates. Lamarck was also an evolutionary theorist, and he - believed that a single characteristic acquired by an animal during - its lifetime could be passed on to its descendants by heredity - (modern genetic theory was unknown at that time). He saw that - evolution must have taken a long time to occur, and he supported the - principle which has since become known as uniformitarianism.] - - [Illustration: Georges Cuvier, 1769-1832, was a French anatomist and - paleontologist who specialized in the study of animals with - backbones, the vertebrates. He had a long and brilliant career as a - professor, eventually becoming France’s minister of the interior in - 1832. His skill as a comparative anatomist enabled him to understand - how vertebrate fossils should be reconstructed to form a complete - skeleton, and he was one of the first to use the small muscle scars - on fossil bones to reconstruct the extinct animal’s musculature. His - classic work _Récherches sur les Ossemens Fossiles de Quadrupèds_ - was published in 1812. He is known for his theory of a series of - natural catastrophes, each supposedly obliterating all extant life, - to account for the great variety of ancient fossils. This theory was - later supplanted by the theory of continuous evolution supported by - Darwin, Lyell, and others.] - - [Illustration: Charles Darwin, 1809-1882, is today a household name - that is still invoked in controversy as it was more than a hundred - years ago. An extraordinarily patient and insightful biologist, - Darwin contributed the idea of natural selection, the “weeding out” - of unfit individuals and species, and described it as the guiding - principle of the evolution of life on this planet. His book _On the - Origin of Species by Means of Natural Selection_, published in 1859, - is the most important landmark in evolutionary studies. This was the - culmination of decades of work, leading to conclusions startlingly - similar to those of his fellow Englishman, Alfred Wallace. Darwin - knew nothing of the genetic principle of biological heredity and - variation, which has now assumed equal importance with natural - selection in the study of the evolution of life. For - paleontologists, Darwin’s work meant they must look for transitional - forms of life and not content themselves with Cuvier’s assumptions - that past life forms had been static and unchanging. During his - travels in South America, Darwin contracted a disease, now known as - Chagas’ disease, and suffered intense pain and discomfort the rest - of his life. He died of a heart attack on April 19, 1882, and was - buried in Westminster Abbey in London a few days later.] - - [Illustration: Charles Lyell, 1797-1875, revolutionized the study of - geology partly by publicizing the earlier work of James Hutton, who - died the year Lyell was born in Scotland, and partly by infusing the - science with his own highly disciplined point of view. His greatest - contribution was the firm establishment of Hutton’s principle of - uniformitarianism, or uniformism, which became the foundation for - all modern geological work. Put simply, this is the principle that - the processes we see operating to form and shape the Earth today - have always operated in the past. Once this is admitted, it becomes - clear that past geological time is vast, not short, a truly stunning - notion for Lyell’s time but a commonplace fact today. The first - volume of his _Principles of Geology_ was published in 1830; in his - later works he championed Darwin’s own revolutionary point of view, - adding his own powerful arguments in support of the idea of natural - selection.] - - [Illustration: Alfred Wallace, 1823-1913, was the co-originator, - with Darwin, of the principle of natural selection, or “survival of - the fittest.” The main difference between the two was that Wallace - did not believe that natural selection explained things as well as - Darwin thought it did, which has been borne out to a large extent by - modern studies of genetic variation. Wallace worked in South - America, along the Amazon and Rio Negro rivers, and in East Asia. He - showed that the animals on either side of a line between Borneo and - the Celebes Islands are radically different in their makeup and - origin. Now known as “Wallace’s Line,” his work has been vindicated - by additional modern studies. Although Wallace did not become as - well known as Darwin, his brilliant, independent studies lent a - great deal of weight to the Darwinian view of evolution.] - - [Illustration: _The largest divisions of geologic time are eras, - shown above in chronological order from the oldest on the bottom to - the most recent on top. The scale at left shows the relative - duration of each era. As the chart shows, geologists further divide - time into periods and, in the Cenozoic Era, into epochs. The - fossilization of animals in the Agate Springs area of Nebraska took - place in the Miocene Epoch. Adjustments to this time chart are made - as new data becomes available, so it should not be thought of as an - unchanging reference. This diagram is adapted from one in The - Emergence of Man series published by Time-Life Books._] - - Geologic Time Chart - Period Epoch Time span (years before present) - - Cenozoic Quaternary Pleistocene 10,000 to 2 million - Tertiary Pliocene 2 to 5 million - Miocene 5 to 23 million - Oligocene 23 to 34 million - Eocene 34 to 55 million - Paleocene 55 to 65 million - Mesozoic Cretaceous 65 to 138 million - Jurassic 138 to 205 million - Triassic 205 to 240 million - Paleozoic Permian 240 to 290 million - Carboniferous 290 to 365 million - Devonian 365 to 410 million - Silurian 410 to 435 million - Ordovician 435 to 500 million - Cambrian 500 to 570 million - Precambrian 570 to 4,500+ million - - - The Geologic History of Agate - -Although the whole story of Agate Fossil Beds dates from the formation -of the Earth four and one half billion years ago, only the last 600 -million years is known in detail. It was about 600 million years ago -that many plants and animals began to have hard parts—parts likely to be -preserved as fossils. The few fossils contained in older rocks are often -folded, twisted, squeezed, and distorted so that their original -character is all but erased. That isn’t always the case, of course. Some -of these old rocks, the Belt Series in Montana, look as though they were -deposited only a few million years ago; they contain traces of algal -colonies indicative of the generally simple life forms on the primitive -Earth. The old rocks, deposited during the first four billion years of -Earth’s history, record the Precambrian Eons, spanning eight-ninths of -geologic time. - -The evolutionary development of skeletal remains has aided in the study -of geologic history. The last 600 million years have been divided into -units for ease of discussion and comparison. The three largest divisions -are the eras—Paleozoic (ancient life), Mesozoic (middle life), and -Cenozoic (recent life). We are viewing all this from our vantage point -at (what is now) the most recent episode of the Cenozoic. - -To begin at the known beginning, we only need go back to the start of -the Paleozoic Era some 600 million years ago. No Precambrian, Paleozoic, -or Mesozoic rocks can be seen around Agate, but we know from rocks found -in comparable areas about what to expect under the surface at Agate: -thousands of meters of sedimentary rocks, most of them laid down in an -ocean. During the Paleozoic and most of the Mesozoic eras, up until -about 70 million years ago, the west-central United States was covered -by seas. The area now occupied by the Rocky Mountains was then a long -north-south trough in which thick sediments collected. To the east, the -present Great Plains area was the floor of a shallower sea. Sediments -collected in the trough and on the sea bottom. Gradually, over a period -of 530 million years, the sediments accumulated to a thickness of over -2,100 meters (6,900 feet). A dynamic “give-and-take” process, this -sedimentation was the result of periods when the sea rose and fell -several times. - -If the Paleozoic sounds a little dull, it’s because we haven’t told the -whole story. During the Paleozoic Era, all the major groups of organisms -evolved. The seas swarmed with trilobites and shellfish of all kinds, -some weird and fantastic and some very like those alive today. With them -coexisted fish and sea-lilies, seaweeds and giant swimming “scorpions.” -For the first time, plants and then animals came out of the sea to live -on the land. These events and creatures are preserved in Paleozoic -rocks. The Mesozoic Era saw the development of mammals from reptiles, -the rule of giant dinosaurs, and the beginnings of flight. Strange -reptiles evolved and returned to the sea, or glided through the air on -motionless wings. The Sundance Formation, deposited in the northern -Rocky Mountains about the middle of the Mesozoic Era, is noted for the -masses of bullet-shaped squid shells found in it. Water, land, and air -were full of life. - -In the Middle Mesozoic, the trough drained and much of it became an area -of swamp and tropical forest extending from Montana to southern Utah. -This was the domain of our largest dinosaurs, giant reptiles whose bones -were preserved in impressive numbers. Como Bluff and Bone Cabin, -Wyoming; Morrison, Colorado; and Dinosaur National Monument and -Cleveland, Utah, are the sites of quarries where many fine specimens of -_Apatosaurus_, _Diplodocus_, _Stegosaurus_, and _Allosaurus_ have been -collected. These caches of bones have made our large museums showplaces -known throughout the world. - -During the last 65 million years of the Mesozoic, the trough fluctuated -up and down. During much of that time a broad, shallow sea covered -central North America from the Gulf of Mexico to the Arctic Ocean. The -sea was filled with fish like the giant _Portheus_ (3.5 meters/11.5 feet -long), with squid-like animals floating about in elaborate chambered -shells, and with reptiles which had gone back to the water. Where there -was a broad coastal plain, it swarmed with dinosaurs, the ones that make -Lance Creek, Wyoming and Hell Creek, Montana famous collecting grounds -for museum field parties. Yet at the end of the era the trough was a -seaway again, and in the Agate area a final blanket of black mud, the -Pierre Shale, was deposited in the sea. - -At the end of the Mesozoic Era a profound change came over the land. The -trough, with hundreds of meters of sediments accumulated on its bottom, -was drained and folded by pressures built up in the Earth’s crust. To -the south, the Colorado Plateau rose slowly and smoothly; to the north -folding and faulting built complex mountain ranges. This uplift is -called the Laramide Revolution because of the magnitude of the change it -made on the face of the continent. - -At the beginning of the Cenozoic Era, about 65 million years ago, the -Rockies and the Great Plains were slowly rising. Rains fell and rivers -carried the water, wearing away the old sediments. Some sediments were -carried west into the Pacific Ocean, or deposited on the land and -covered over by new sediments. Some sediments remained within the -Rockies, settling into basins during the early Cenozoic. Other sediments -were carried east by the rivers, beyond the Great Plains and into the -Mississippi Embayment. Mountain building and erosion tended to cancel -out one another in the Rockies, preventing the mountains from reaching -great heights. The mountain bases were perhaps no more than 300 meters -(1,000 feet) above sea level, and the crests perhaps 600 meters (2,000 -feet) above that. - -Before long, the basins within the Rockies filled with sediments. The -basins overflowed, and at last sediments began to cover the Great -Plains. This was near the end of the Eocene Epoch, about 35 million -years ago. Subtropical rivers, flowing sluggishly, rolled out over their -banks and left their loads of silt and clay on the featureless plain. - -The oldest part of the blanket of sediments, the White River Beds, -extended from Saskatchewan to Texas. Nearly 200 meters (650 feet) of -muds, clays, silts, and river gravels were laid down during the 11 -million years of the Late Eocene and Oligocene Epochs. Magnificent -exposures of these beds can be seen at Scotts Bluff National Monument in -the valley of the North Platte, in Toadstool Park north of Crawford, -Nebraska, and particularly in the Big Badlands of southwestern South -Dakota. - -The kind of floodplain deposition characteristic of the Oligocene on the -Great Plains ended about the beginning of the next epoch, the Miocene. -In Nebraska the process continued, but eventually erosion began wearing -away the accumulated sediments. The land to the west was uplifted a -little, and the streams flowed off the high ground fast enough to cut -down into what they had just deposited. On this eroded surface, the -layers of tan silts, fine sands, and clays known as the Gering Formation -were deposited. - -On top of the Gering Formation, in the Late Oligocene, is the Monroe -Creek Formation, the oldest formation actually exposed in the Agate -area. This formation is named for exposures in Monroe Creek Canyon north -of Harrison, Nebraska, and may be up to 75 meters (245 feet) thick. You -can see a little of the Monroe Creek Formation’s pinkish silts and -volcanic glass shards exposed in the valley of the Niobrara River. Where -it is more exposed by erosion than at Agate, the Monroe Creek Formation -forms magnificent cliffs along the Pine Ridge and similar areas of high -ground. The best local examples are at Fort Robinson State Park between -Harrison and Crawford, Nebraska. A close look can be obtained in Smiley -Canyon just west of the fort, where old U.S. Highway 20 is maintained as -a scenic drive. - -After the Monroe Creek interval, near the end of the Oligocene, -deposition of the famous Agate Fossil Beds began. Geologists have named -this sequence of grayish silts and sands the Harrison Formation for its -occurrence near Harrison, Nebraska. A short interval of erosion -separates it in some areas from the Monroe Creek Formation below, and -its coarser sands indicate increasing uplift of lands to the west. Wind -played a smaller role in deposition than in Monroe Creek times, though -that is certainly not true at the _Stenomylus_ quarry. The Harrison -Formation was the last of the truly widespread deposits seen in the -Miocene of the Great Plains. Many rivers flowing eastward from the -Rockies contributed sands to Wyoming, South Dakota, and Nebraska. - -Generally the Harrison Formation and the overlying Marsland Formation -are only moderately fossiliferous, but along the Niobrara River here at -Agate, Nebraska, the accumulation of rhinoceros and camel skeletons is -one of the wonders of the fossil world. Here, thousands of animals -perished in two droughts which coincided with conditions perfect for -preservation. About two kilometers (1.2 miles) east of the Monument -headquarters the dried-out, mummified bodies of perhaps a hundred or -more little camels, _Stenomylus hitchcocki_, were buried under windblown -sand during the first drought. - -Shortly after the camels were buried there was a brief period of erosion -and then the Marsland Formation began to be deposited. Named for a -little village east of Agate, the Marsland Formation consists of basal -river channel deposits followed by about 45 meters (150 feet) of -wind-blown tan-and-gray sands. It is in one of these river channel -deposits that the Agate rhinoceros quarries are located. - -The second drought occurred early in Marsland times and literally -hundreds of the little rhino, _Menoceras_, were preserved when their -carcasses were broken up by a reborn river and buried like a mat of -jackstraws in a river lake. - -After Marsland times there was more erosion, in some places by rushing -streams that cut down 91 meters (300 feet) through soft sediments, to -the top of the Monroe Creek Formation. In these channels the -Runningwater Formation was deposited because it filled in the stream -valleys and wound around the high spots. This channel deposit is not -found everywhere, but it does have an equivalent in southwestern South -Dakota. Other deposits of similar age are found in many parts of the -Great Plains, and they contain fossil animals like those found in the -Runningwater Formation. - -The turbulent streams which deposited the Runningwater Formation were -flowing off newly uplifted land to the west. This was the beginning of -the most recent major uplift of the Rocky Mountains, and it signalled a -great change in the pattern of deposition on the Great Plains. No longer -would broad blankets of sediments be deposited by sluggish streams -originating in the low, broad warp of the Rockies. - -This latest uplift is called the Rocky Mountain Revolution. It brought -on a period of alternating cycles of deep channel cutting and stream -deposition. Floodplain deposits were restricted to narrow ribbons in -river-cut valleys. Even more important than the changes in deposition -was the effect of this uplift on the climate. As the Rockies began to -rise to their present height, the climate became increasingly arid and -the tree-dotted savanna of the old Great Plains gave way to grasslands. - -Several kilometers south of Agate, the Sheep Creek Formation was laid -down during the Middle and Late Miocene. The appearance of the grazing -horse _Merychippus_ in these channel and floodplain deposits marked the -establishment of the grasslands as the newly dominant ecosystem of the -Great Plains. At that time the “modern” fauna began to replace the old, -and new patterns of life were established. - -Again rejuvenation of the stream system, probably reflecting further -uplift in the west, started another erosional interval that began to -wash away the beds just deposited. When deposition followed in the Late -Miocene, a new series of channel and floodplain deposits, the Lower -Snake Creek Beds, was laid down. On them was deposited the Upper Snake -Creek Beds, and together they span most of the Late Miocene and the -Early and Middle Pliocene epochs. Harold Cook collaborated with W. D. -Matthew of the American Museum of Natural History, publishing important -papers on the numerous finds from these fossiliferous deposits. Animals -new to science are still being discovered in the Snake Creek Beds. - -After Snake Creek times, the area immediately around Agate was left out -of the mainstream of events on the Great Plains. The continuing uplifts -of the Rocky Mountains were no longer recorded here in cycles of -downcutting and channel deposition. If the cycles continued here, all -traces have now been washed away—an unlikely possibility. The view from -the high plains above the valley of the Niobrara River reveals only the -rolling surface of the pre-Runningwater deposits. - -A more complete record is found in the river terraces of major streams, -the North Platte to the south and the White and Cheyenne Rivers to the -north. These terraces tell the story of continuing uplifts. To the -south, east, and northeast of the Platte the record is also written in -fossil bones, but these are outside the scope of our story. - -Northwestern Nebraska, northeastern Colorado, southeastern Wyoming, and -southwestern South Dakota today remain a promised land for -paleontologists studying mammal life in North America during the middle -and later Cenozoic Era. The fossil deposits in the Agate area are -surpassed in importance only by the Late Eocene and Oligocene deposits -of the Big Badlands and Pine Ridge in South Dakota. - - - Ecology: Change and Adaptation - -During the Age of Mammals (the Tertiary Period), three major -environments dominated western Nebraska. The first of these occurred -during the Paleocene, Eocene, and Oligocene epochs. This was a forest -system where trees were the major component of the flora. Meadows were -found only in scattered areas and can be considered a minor element. -There is no geologic or paleontologic record of the Paleocene and Eocene -in the Agate area, but when our present knowledge of the early Tertiary -Rocky Mountain floras is projected eastward a bit, a predominantly -forested landscape is indicated. - -It is in some ways ironic that while the Oligocene land-laid sediments -of southwestern South Dakota, western Nebraska, southeastern Wyoming, -and northeastern Colorado contain one of the best vertebrate fossil -records in the world, the plant record is almost non-existent. -Unfortunately the groundwater chemistry that was so right for the -preservation of bones was hostile to the preservation of plants. -Hackberries (_Celtis_) and walnuts (_Juglans_) are the only recorded -plant species from the Oligocene in this very large area. Because these -are such widespread and climatically tolerant types, they tell us almost -nothing about the environment. Indications of the flora at Agate may be -obtained, however, from the extraordinary Late Eocene flora found at -Florissant, Colorado, south of Denver. Although this deposit does -contain some upland species, it generally indicates a warm temperate -forest including such things as horsetail rushes, ferns, cattails, -grasses and sedges, poplar, willow, birch, oak, elm, serviceberry, -sycamore, maple, sumac, and—of course—hackberries and walnuts. - -During the Early Miocene, slightly changed climatic conditions brought -about by minor uplifts in the Rocky Mountain area transformed the -immediate area of western Nebraska into a savanna of mixed trees and -grasslands. This second system probably reached its climax just about -the time the Harrison Formation was being laid down during the Early -Miocene. This was a savanna with scattered clumps of trees, gallery -forests, and grasslands. The modern world’s richest and most diverse -fauna of hoofed mammals can be found on the savannas of east Africa. On -the savannas, grazing and browsing (grass eating and leaf eating) -adaptations of the larger plant eaters are represented. - - [Illustration: 35 million years ago] - - [Illustration: 25 million years ago] - - [Illustration: 15 million years ago] - - [Illustration: 35 million years ago, life along the Niobrara River - near Agate would have appeared something like this. Two oreodons (1) - have startled an alligator (2) and two hippopotamus-like - _Aepinacodons_ (3) along the river bank. Climbing a tree is an - opossum (4), one of the oldest forms of life in the world today. - Note the many familiar trees and plants, particularly the - cottonwood, willow, beech, dogwood, and cattail.] - - [Illustration: 25 million years ago, a savanna dominates the Agate - landscape. Copses of oak and pine are interspersed with open - grassland. In the foreground are several _Parahippus_ (1), an - ancestor of today’s horse, while _Oxydactylus_ camelids (2) move - away into the distance and, overhead, a hawk (3) searches for - rodents.] - - [Illustration: 15 million years ago, the Agate landscape has changed - to an open prairie. A small herd of _Merychippus_ horses (1) races - toward the arroyo in the distance, narrowly escaping ambush by a - large, leopard-like cat known as _Pseudaelurus_ (2). A few - cottonwoods, elms, sycamores, and willows grow along the river, but - cedars predominate in the arroyo in the middle ground, where they - are protected from winds that sweep across the plains. Though the - animals have changed, the landscape is essentially like this today.] - -In western Nebraska the savanna environment lasted for only a very short -time, in a geologic sense, before it gave way to a wave of advancing -grasslands, the third phase of Tertiary environment in the area. -Tallgrass prairie such as that still found 325 kilometers (200 miles) -east of Agate a century ago must have been first among the grassland -types. Trees, when present at all, were restricted to the borders of -streams. Then as the climate became even more arid the prairie or tall -grass retreated eastward, while the forest moved before it even farther -to the east and south, and the modern shortgrass of the plains took its -place. Today Agate lies in one of the valleys whose rivers are slowly -dissecting the High Plains. - -The modern plains are dominated by short, curly, sodforming buffalo -grass, a plant well adapted to the area’s light rainfall, periodic -droughts, low humidity, rapid evaporation, and high winds. The dominant -vertebrate animals are burrowers and grazers, and dogs are the primary -carnivores. Hoofed animals such as the pronghorn, the ultimate in the -running and bounding adaptation; jumpers and hoppers, such as -jackrabbits and jumping mice and rats; and burrowing mound builders, -such as the prairie dog (a large ground squirrel), the pocket gopher, -and harvester ants typify the major occupations of plains animals. - -The environmental type seen on the Great Plains of North America is -elsewhere best developed in the Pampas of Argentina, the Puztas of -Hungary, the Veld of Africa, and the Steppes of Russia. In the climatic -classification of the climatologist and geographer, the term _steppe -climate_ is applied to all these areas, the Great Plains included. - -If the savanna is the halfway station between forests and grasslands, -then the fossil fauna of the Early Miocene at Agate was a fauna in the -beginning of a serious transition. In the vicinity of Agate, the fauna -from the Late Oligocene was dominated by mammals with low-crowned teeth. -The crown is that part of the tooth which is above the roots and exposed -beyond the gums. Among the herbivores, the browsers can live a long life -with low-crowned teeth. But when any appreciable amount of grass, -particularly the short, tough grass of the plains and the abrasive dirt -and sand that accompanies it, becomes part of an herbivore’s diet, there -is a great increase in the rate of tooth wear. Teeth which have evolved -for browsing quickly wear down to the gums and the individual dies of -starvation. - -Accompanying the development of extensive grasslands came the evolution -of the high-crowned tooth. This process begins simply with the growth of -a taller crown that erupts completely from the gum right after the milk -or deciduous teeth fall out. Another step is the development of a longer -or higher crown most of which is held in the jaw and then slowly pushed -out as the chewing surface is worn down. This is the “mechanical pencil” -effect in that the “lead” may be pushed out as needed. Teeth of this -type are perhaps best seen in the later horses. From their appearance in -the Late Paleocene until the end of the Early Miocene, all horses had -low-crowned teeth. With these they could chew the soft leaves and twigs -of trees and shrubs, first in the forests and later in the groves and -clumps on the developing savanna. By Early Miocene (i.e., Harrison) -times, there was only a slight increase in crown height in _Parahippus_, -but it had evolved an increasingly complicated crown pattern which -served to lengthen the time it took for the tooth surface to wear down -flat. With the greater aridity of the changing climate, the teeth of -_Parahippus_ became higher and higher crowned, as the individuals with -the best teeth lived longest and had greater opportunity to produce -offspring than those with lower-crowned teeth. In some species, the -tooth material called cement, which ordinarily covers the roots of the -teeth, began also to cover the enamel of the crown and give additional -wearing strength to the teeth. Soon after the beginning of the Middle -Miocene, two species had developed cement-covered teeth whose crowns -were high enough to warrant placing them into two new genera of horses, -_Merychippus_ and _Protohippus_. These forms, first recognized in the -Lower Sheep Creek Beds in the Agate area, were the first horses to use -the mechanical-pencil effect, having cheek teeth that continued to rise -out of the jaw as the tooth was worn down. _Merychippus_ later gave rise -to a line of three-toed horses, which lived on into the Pliocene; -_Protohippus_ gave rise to a line which ultimately led to _Equus_, the -modern horse. - -The ultimate in high-crowned teeth occurs when roots do not ever form at -the base of the tooth; additional crown material is constantly added at -the bottom of the tooth as it is pushed out of the gum. This type of -growth resembles the foundry process of extrusion, where metal or -plastic is pushed through a mold to produce a continuous strand. This -extreme development is seen in the incisors or gnawing teeth of beavers, -gophers, and other Late Oligocene rodents, and in the grinding teeth of -only a few forms. The cheek teeth (the grinders) of modern pronghorns -(artiodactyls), gophers (rodents), and rabbits (lagomorphs) are typical -of this kind of development today. During the Middle Oligocene, only the -strange little fox terrier-sized, flat-headed oreodon _Leptauchenia_, -the tiny “deer” _Hypisodus_, and the rabbit _Palaeolagus_ had mechanical -pencil-type teeth. Some of the rhinos then had fairly tall crowns, but -these don’t really qualify as high-crowned teeth. It was not until later -on, when the grasslands took over completely, that high-crowned teeth -really came into their own. - -There was no dramatic change in the fauna at the beginning of the -Miocene, and many Oligocene genera carried over into the new epoch. Most -of the Eocene hold-overs, primitive animals that had survived in the -extensive forests, became extinct when the forests began to retreat; but -for the most part the record continued undisturbed. This is to be -expected where the deposition of sediments continues without -interruption. (Remember that the epochs, periods, and eras were -originally based on breaks in the European sedimentary record reflecting -local events which would not necessarily show up in North America’s -sediments.) - -By the time the Harrison Formation was deposited, the development of the -halfway world of the savanna was beginning to affect the fauna. Although -the Oligocene and the very earliest Miocene mammal faunas were highly -varied and rich in types of animals, much of this was due to the -continued presence of primitive and archaic forms, and to the explosive -development of rhinos and oreodons. With the savanna becoming the -dominant landscape, the shift to grazing and away from browsing became -evident. Or, at least, the presence of animals that both browsed and -grazed was indicative of changing times. As was mentioned earlier, -grazing and burrowing are characteristics of plains herbivores. In such -a transitional period we would expect to find an increase in burrowers -and grazers as grasslands became more common. - - - Evolutionary Change - - Animal species respond to environmental changes in a variety of ways. - Simply put, some species die off, some adapt physically, and some move - to a different habitat. On the next few pages are examples showing how - three species responded to long-term environmental changes in the area - around Agate Fossil Beds. The _Stenomylus_ line died off; _Miohippus’_ - evolutionary line remained a grazing animal but changed physically - over the years, eventually becoming the modern horse; and the - _Palaeocastor_ line moved from land to water, gradually evolving into - the beaver. - - Each of these three animals is portrayed here with partial skeleton, - musculature, and outer skin to help you see its general composition - and to emphasize certain physical features that developed in the - species over time. Paleontologists, of course, work this way. From - fragments and bones they reconstruct full skeletons, and from surmises - about muscular structure, often based on present-day animals, they - project the appearance of the animal. The artist, in this case Jay - Matternes, then brings together these bits of evidence to give us a - picture of life long ago. - - - Stenomylus - -A small, gazelle-like camel similar to the present-day gerenuk of - Africa. _Stenomylus_ is the second most common animal found in the - fossil beds at Agate. _Stenomylus_ had hard hooves like modern - antelopes and deer, unlike modern camels which have flesh-padded feet - adapted to desert terrain. The three-hued coat is inferred from the - coat of the modern gazelle, a similar form in adaptation. - _Stenomylus’_ evolutionary line eventually died out in North America - at the end of the Pleistocene. No one knows why both camels and horses - died out on this continent. - - The distance between grid lines represents five centimeters. - - [Illustration: 1 The ears moved in a parallel fashion, not - independently; the parallel movement is inferred from modern - llamoids, to which _Stenomylus_ is related. - - 2 _Stenomylus’_ musculature was adapted for high-speed running, - similar to the present-day pronghorn. - - 3 The back structure suggests that _Stenomylus_ would have made - short, choppy leaps, not the graceful, arcing leaps of a modern - impala. - - 4 Limbs were long in proportion to the body, allowing the animal to - run with great speed. - - 5 _Stenomylus_ had a hard, chitinous hoof, an adaptation for greater - running speed, and for sure footing on rough terrain.] - - - Miohippus - -Over the last 60 million years the horses have evolved from small, -terrier-sized animals to the diversity of size we know today, from the -huge Clydesdales to the diminutive Shetland ponies. The three-toed early -horse known as _Miohippus_ was about the size of a sheep. The -descendants of _Miohippus_ apparently went in two directions in their -evolution: One group continued to be forest-grazing, three-toed horses -that eventually reached the size of modern horses but died out later. -The other group, through such intermediate forms as _Parahippus_, became -grassland forms that led eventually to the modern one-toed horses. -Horses became extinct in North America at the end of the Pleistocene, -but no one knows why. They continued to evolve on other continents and -were re-introduced in historic times. - - The distance between grid lines represents five centimeters. - - [Illustration: 1 The back was straighter and stiffer than in earlier - horses, partly because of the increasing size of the animals and - partly to allow sustained open-plains running. - - 2 Limbs were long in proportion to the body, an evolutionary trend - in the horses for speed in open-plains running, rather than darting - about in forests. - - 3 Most of the weight of the animal was on the middle toe, which has - become a single toe in modern horses. This is an adaptation for - endurance and stability in open grasslands. - - 4 The upright mane is a primitive horse characteristic; wild horses - today have reverted to this trait. - - 5 The coat is shown as striped, a probable holdover from earlier - horses that dwelled in forests, where a striped coat would provide - camouflage. - - 6 A large, deep mandible supported teeth adapted to grazing and the - grinding of grasses and other wild plants. The teeth were - deep-rooted and continuously erupted as the surface was worn down by - the grit and dirt that came with the large quantities of plant food - consumed daily.] - - - Palaeocastor - -_Palaeocastor_ was an ancient beaver whose mode of life was like that of -a modern prairie dog—land-oriented instead of water-oriented. -_Palaeocastor_ was small, about 12 centimeters (5 inches) high, and -about 30 centimeters (12 inches) long. Its fossilized spiral burrows, -called _Daemonelix_, survive to tell us what its habitation was like, a -feature unique to _Palaeocastor_ among all the fossil beavers. The -_Daemonelix_ shown here dwarfs a member of Olaf A. Peterson’s field crew -from the Carnegie Museum. The bones of a _Palaeocastor_ and one of its -predators were found at the bottom of one such burrow, helping to prove -that _Palaeocastor_ was responsible for making these corkscrew holes in -the ground. - - The distance between grid lines represents five centimeters. - - [Illustration: 1 The powerful jaw and musculature allowed for - grazing on grasses and other plants, as well as masticating. The - teeth were deep-rooted and would continue to erupt as the surface - was worn down. - - 2 The complex musculature supported the use of the forelimbs in - burrowing. _Palaeocastor_ had a collarbone or clavicle, like us, for - greater agility in using the forelimbs. - - 3 The forelimbs were adapted to burrowing in the ground. - - 4 The tail is like that of a modern burrowing rodent, such as a - muskrat, whereas the modern beaver has a different, very specialized - tail.] - - [Illustration: Daemonelix] - -A grazing animal is fairly easy to recognize, but how can we recognize a -burrower? Some have radically adapted limbs and claws. Obvious cases are -the common garden mole and the armadillo. The mole has powerful -attachments for the muscles of the upper arm on the humerus, a bone so -flattened that its width has come to match its length. Moles also have -long, broad digging claws. The armadillo, which is also a digger but not -a burrower in the same way a mole or a gopher is, has large curved claws -for digging. Moles did start to become quite common in the Late -Oligocene, so we can assume that a good burrowing environment was -present. - -Another group which became extraordinarily common in the Late Oligocene -of western North America was that of the ancestral pocket gopher. Direct -proof that this group actually burrowed does not exist, but the -abundance of fossil gophers suggests that they might have lived -underground in colonies. - -A real surprise at Agate is the number of beaver burrows. The famous -_Daemonelix_ or “devil’s corkscrew” attests to the dense population of -_Palaeocastor_. By that relatively advanced stage of beaver evolution, -the animals might be expected to behave like the modern-day muskrat, -perhaps digging dens along stream borders and spending some of their -time in the water. The presence of skeletons in the spiral burrows, -however, indicates that _Palaeocastor_ was primarily a burrower, one -which perhaps lived very much like our present-day prairie dog. Despite -that, there is no apparent structural modification to indicate burrowing -abilities. - -Changing environmental conditions were pushing _Palaeocastor_ toward -extinction in the Early Miocene. The disappearance of that ancient -beaver, while not unusual, presents a problem for the careless observer -who might assume that ancient animals behaved like their modern -counterparts. The burrowing beavers of Miocene Agate certainly have no -modern counterparts. - -While we can delineate in a general way the prehistoric life of Agate, -we can’t describe the past in any detail. Plants most directly reflect -the effects of climate—and plant fossils are absent at Agate. As the -base of the food chain, plants carry the influences of climate on to the -plant-eating animals. From the numerous animal fossils found at Agate we -have learned most of what is known about the environment of that time. -Sediments tell a good part of the story, and floras from other -localities help, but much of Agate’s ancient ecology must be inferred -from the bones. - -Today, standing on the porch of the visitor center or walking along the -path to University and Carnegie Hills, visitors find themselves in the -midst of the shortgrass prairie. Five distinctive plant communities -share this prairie, coexisting in a dynamic relationship which depends -upon local climate variations. - -Even to the untrained eye, it is evident that the basic short-grass -pattern has been modified by the shape of the land and by the Niobrara -River. In the stream valley, along the tributaries, and on shaded -north-facing slopes, the shortgrass community is mixed with taller -grasses. If a dry cycle began, the short grasses would take over the -whole area by migrating downslope from the exposed prairies. Of interest -is the fact that over-grazing by either domesticated or wild animals -will have the same effect as a dry period in that taller grasses will be -replaced by short ones. - -Let’s examine the five communities present today so we can appreciate -the complexity of relationships between living things and the earth upon -which they depend. - -First, we can begin in the Niobrara River itself. The river’s -water-dwelling plant inhabitants include algae, which grow underwater. - -Between the river and the dry ground is a second community—the -marsh—which is often more wet than dry. The marsh has its own -characteristic plant association. Most familiar are the cattails, mints, -and willows, but just as important ecologically are arrowleaf, rush -sedge, marshweed and blue verbena. These are moisture-loving plants that -thrive on being thoroughly soaked during the wet part of the year. - -Beyond the marsh on the valley floor is a third community. Here the -water table (the top of the saturated soil and rock zone) is close -enough to land surface that the plants can easily send their roots down -into the saturated zone. Here, in what the plant ecologists call the -“sub-irrigated floor plain” we find a mid-grass community. Eighty-five -percent of the vegetation is slender wheatgrass. Its wheat-like heads -may, under favorable conditions, grow to a height of one meter (three -feet). At Agate it is seldom over knee high. Kentucky bluegrass takes -care of another 10 percent of the plant population. Imported from Europe -as a pasture grass in the 1600’s, it spread so rapidly that it often -beat the settlers onto new land as they moved westward. The remaining -five percent includes imported redtop and such native grasses as -switchgrass, foxtail barley, little bluestem, prairie cordgrass, and -inland saltgrass. Wildflowers such as Flodmon thistle, yarrow, heath -aster, salsify, and blue-eyed grass complete the community. - -Moving farther away from the stream, we rise up onto terraces within the -valley. These terraces represent levels where the stream paused in its -downcutting and cut sideways for awhile. At a drier level, on deep, -well-drained sandy soils, they support the fourth or mixed-grass -community. - -No exotics have yet appeared in this plant community. The grasses -include prairie sandreed, sand bluestem, blue grama, needle-and-thread -grass, and Indian ricegrass. Wildflowers include the prominent phlox, -penstemon, and lupine. Unwelcome (to man and his grazing animals) is -_Astragalus_, the selenium-concentrating plant better known as loco -weed. The brittle prickly pear and spiderwort cactus are found here too. - -At higher levels in the terrace community, slightly steeper slopes and -shallower soils cause some change in this mixed-grass assemblage. Here -the dominant grasses are little bluestem, threadleaf sedge, -needle-and-thread grass, and blue grama. Lupine disappears, and common -pricklypear becomes the only cactus. In this community is found the -yucca, its flowers a beautiful soft yellow in season and its spiny -leaves painful at any time of the year. Avoid this plant; yucca spines -break off under the skin and soon cause irritating festers. The yucca -moth, often seen flying around the yucca seed pods, lays eggs in the -plant’s lemon-sized fruits. Inside the fruit are long rows of flattened, -wedge-shaped seeds. When the yucca moth eggs hatch into caterpillars, -they eat their way through the seeds, killing them. On the other hand it -is the yucca moth with its long tongue that is solely responsible for -pollinating the yucca flower! If you find a yucca fruit in early summer, -you can (elsewhere than in the park) slice through it and see the -caterpillars at work. - -On the high bluffs and overgrazed terraces is the fifth community, the -short grass. This community too can be divided into two slightly -different parts. The bluffs support blue grama grass, needle-and-thread -grass, and Sandberg blue grass. Flowers and shrubs include _Eriogonum_, -brittle pricklypear cactus, pepperweed, penstemon, broom snakeweed, -fringed sagewort, and yucca. The other part of this community, the -overgrazed terraces, have threadleaf sedge, needle-and-thread grass, and -blue grama. Except for the familiar penstemon, all the flowers are -restricted to this community. Gronwell, menzania, and bee plant are -indicators of overgrazing. - -Certain cyclical variations are characteristic of these plant -communities. First, the shortgrass and mixed-grass areas ebb and flow -with changing moisture conditions from year to year. Second, grass -populations change with the seasons. Cool-season grasses (foxtail -barley, Indian rice grass, Kentucky bluegrass, needle-and-thread grass, -Sandberg blue grass, and slender wheatgrass) flourish during spring and -fall. During the warm summer the blue grama, inland saltgrass, little -bluestem, prairie cordgrass, prairie sandreed, and switchgrass -predominate. This natural adaptation to seasonal conditions uses the -greatest potential of the growing season and at the same time provides -species that will flourish in both wet and dry cycles. - -After reading this last section, you might look back at the section on -Early Miocene ecology. Comparison reveals that a great deal of -information can be obtained by examining living plants. In contrast, the -lack of fossil flora from the Early Miocene at Agate has resulted in a -scarcity of ecological information from that early epoch. Scientists -begin their reasoning by such comparisons; you can begin your own -exploration of the past in the same way. - - - - - 3 Guide and Adviser - - - [Illustration: Ask a ranger for directions to the protected example - of a Devil’s Corkscrew, the fossilized burrow of a small, - beaver-like animal called _Palaeocastor_. See pages 68-69 for more - information about this interesting animal.] - - - Visiting the Park - - - Contents of This Section - - Visiting the Park 77 - Location - Area - Climate - When to Visit - Visitor Center - Activities - Camping - Nearby Accommodations - Transportation - Establishment Date - Address - Access - Protection 80 - Park Regulations - Safety Tips - Birding Along the Niobrara 81 - Taking the Annual Count - Collections of Agate Springs Fossils 86 - NPS Areas With Fossil Exhibits 88 - Badlands - Dinosaur - Florissant - Fossil Butte - Petrified Forest - John Day - Hagerman - Nearby National Parks 90 - Badlands - Devils Tower - Fort Laramie - Jewel Cave - Mount Rushmore - Scotts Bluff - Wind Cave - Not So Nearby National Parks 92 - Bighorn Canyon - Little Bighorn - Rocky Mountain - Theodore Roosevelt - Armchair Explorations 93 - - - Location - -Northwestern Nebraska 69 kilometers (43 miles) north of Scottsbluff -along the Niobrara River. - - - Area - -1,116 hectares (2,762 acres). - - - Climate - -Temperatures range from winter lows of -38° C (-36° F) to summer highs -of 39° C (101° F). Winter temperatures average 1° C (33° F), and winter -snow averages 60 centimeters (2 feet) for the whole winter. However, -snowdrifts can be much higher. Summer nights are cool, with temperatures -averaging 10° C (50° F). Average annual precipitation is 41 centimeters -(16 inches), with most precipitation in April and May. - - - When to Visit - -Most people go to the park some time between June and August, but you -can avoid the high summer temperatures by visiting in the spring, fall -or—if you don’t mind the cold and snow—in the winter. Spring can be -blustery, but the fall is usually dry and the days are cool. Check ahead -on local weather conditions if you plan a winter visit. Museums and -tourist attractions in nearby Fort Robinson are open Memorial Day to -Labor Day. - - - Visitor Center - -A ranger is on duty to help you and answer your questions. Fossil -exhibits and part of James H. Cook’s personal collection of Indian items -are on display in the visitor center, and publications about the park, -paleontology, and history are on sale. - - - Activities - -A trail from the visitor center takes you on a tour to both University -and Carnegie Hills, with an interpretive display at each. The roundtrip -distance is three kilometers (two miles) and takes about one hour. You -may fish for German brown and rainbow trout in the Niobrara River if you -have a Nebraska fishing license. The park has several tables for -picnickers. - - - Camping - -The park has no camping facilities, but there are state campgrounds near -Harrison and near Fort Robinson, Nebraska, and a commercial campground -on Nebr. 26 between Mitchell and Scottsbluff, Nebraska. - - - Nearby Accommodations - -Hotels, motels, food stores, outdoor supply stores, and restaurants are -available in Scottsbluff, Nebraska. A motel, restaurant, gas station, -and grocery store are in Mitchell, Nebraska, 55 kilometers (34 miles) -south of the park. There are a motel, food store, drugstore, and -restaurant in Harrison, Nebraska, 37 kilometers (23 miles) north of the -park, and there are motels and restaurants at Fort Robinson, Nebraska, -37 kilometers (23 miles) east of Harrison, or 74 kilometers (46 miles) -northeast of the park. - - - Transportation - -Buses—The nearest bus connections are in Scottsbluff, Nebraska. -Airport—Scottsbluff, Nebraska, has an airport served by a scheduled -commercial airline. Rentals—Cars may be rented at the airport or at car -rental agencies in Scottsbluff. - - - Establishment of the park - -June 5, 1965. - - - Mailing Address - - - Agate Fossil Beds - National Monument, 301 River Road, - Harrison, NE 69346. - - - Access - - [Illustration: To reach the park from Scottsbluff, Nebraska, take - Nebr. 26 west to Mitchell, then Nebr. 29 north to the park. From - Fort Robinson, Nebraska, take Nebr. 20 west to Harrison, then Nebr. - 29 south to the park.] - - [Illustration: Plains states] - - - Protection - - [Illustration: The trail from the visitor center takes you across - the Niobrara River, up University Hill to the fossil layer, then to - the fossil exhibit on Carnegie Hill, and back to the visitor center. - The walk takes about one hour.] - - [Illustration: Two fishermen try their luck in the Niobrara.] - - - Park Regulations - -To ensure your safety and to protect the park’s natural and historical -resources, several regulations have been established by the National -Park Service. Collecting of fossils, rocks, plants, or other objects is -not permitted. Please be sure to leave everything as you find it along -the trails and throughout the park for others to enjoy. If you have any -questions about park regulations and policies, please ask the staff. The -rangers are here to help you and to enforce the regulations. - - - Safety Tips - -Though snakes are not prevalent, be sure to watch for rattlesnakes as -you walk about through the park, along the trails, and near the exhibits -at Carnegie and University Hills. Avoid them if you see them, but do not -harm them. As a general rule it is best to keep a good distance from any -wildlife you see, not only to protect yourself and your children, but to -avoid frightening or hurting the animal. It is best to observe wildlife -at a safe distance with field glasses. While walking about the park, do -not take chances by climbing on loose rock, or going into unauthorized -areas, and do not let your children go beyond your control. Park your -vehicle in authorized places and observe the normal rules of road safety -and courtesy while you are in the park, and when entering and leaving -it. - - - Birding Along the Niobrara - - - Taking the Annual Count - -One of the joys of visiting the national parks, author Freeman Tilden -once said, is having an unexpected, provocative experience. You go to a -park to see or do one thing, and you come across something else that -strikes your fancy as well. Tilden called it serendipity. At Agate -Fossil Beds National Monument, one such experience might be -birdwatching. In this piece, Doris B. Gates writes of her annual bird -surveys in this area. - - -In western Nebraska the northern part of the Great Plains ends at the -Pine Ridge, an escarpment circling from Wyoming across Nebraska’s north -edge and winding into South Dakota. A major grass of this mixed prairie -is little bluestem, Nebraska’s state grass, whose rusty-red hue in fall -and winter gives much of the state its characteristic color. - -These plains are rarely broken by cultivation and only a few houses with -their few trees break the landscape. The land’s major change comes where -the Niobrara River, here little more than a narrow creek, cuts a valley -whose rock outcroppings provide homes for rock wrens, chipmunks, and -bushy-tailed wood rats better known as pack or trade rats. - - [Illustration: Swainson’s hawk] - -Here, since 1967, near Agate Fossil Beds National Monument, my partner -and I have taken part in the annual Breeding Bird Survey for the U.S. -Fish and Wildlife Service. Part of one of our survey routes, Highway 29, -crosses the monument’s west end. We know the area—in June at least—quite -intimately, when there is nothing quite so beautiful as a sunrise over -these flower-dotted, green-grassed rolling hills along the Niobrara. - -We go many kilometers and make many bird counting stops, then we drop -into the little valley where the Niobrara flows and suddenly we hear and -see birds in such rapid succession that we have difficulty getting them -all named in the three minutes allowed us under the survey rules. -Actually, three stops are influenced by the river: on the south edge we -have found a common nighthawk, a lark sparrow, and a Say’s phoebe; on -the north end the rock wren sings its un-wrenlike song. Near the bridge, -where a narrow belt of shrubs and trees—mostly willows—hugs the river, -we have logged the following: common flicker, a red-headed woodpecker, -eastern and western kingbirds, western wood peewees, a blue jay, -black-capped chickadees, house wrens, a brown thrasher, robins, yellow -warblers, black-billed magpies, common grackles, black-headed grosbeaks, -American goldfinches, and the non-native house sparrow and starling. -Only once did we see or hear a black-billed cuckoo. - - _continues on page 85_ - - [Illustration: Red-winged blackbird chick] - - [Illustration: Long-billed curlew chick] - - [Illustration: Long-billed marsh wren] - - [Illustration: Canada geese] - - [Illustration: Long-billed curlew male] - - [Illustration: House wren] - - [Illustration: Nighthawk] - - [Illustration: Marsh hawk chicks] - - [Illustration: Killdeer] - - [Illustration: Great horned owl] - - [Illustration: Western meadowlark] - - [Illustration: American bittern] - - [Illustration: Pocket gopher] - - [Illustration: Jackrabbit] - - [Illustration: Hognose snake] - - [Illustration: Fence lizard] - - [Illustration: Coyote] - - [Illustration: Pronghorn] - -If we stop and peer into a large culvert under the highway we may scare -out a cloud of cliff swallows whose mud nests are stuck on culvert -walls. Barn and rough-winged swallows are more rarely seen—usually near -the Agate buildings. - -Near scattered farmhouses we may see logger-head shrikes; by one water -tank we usually find a few killdeer. These and such birds as the -long-billed curlew, upland sandpipers, and sharp-tailed grouse break the -near monotony of such prairie birds as western meadowlarks (Nebraska’s -state bird), lark buntings, horned larks, and chestnut-collared -longspurs. Lark buntings line the utility wires, taking off to sing -their territorial songs, and descending with butterfly-like motions. - -Hawks are here—red-tails, Swainson’s, ferruginous, marsh, and the little -American kestrel—but in small numbers. We search long rows of fence -posts for a burrowing owl and occasionally see one. Great-horned owls -frequent tall cottonwood trees around the Agate ranch buildings. This is -also the country of turkey vultures, golden eagles, and prairie falcons, -but we have not been lucky enough to see them yet. - -Mammals are more elusive. Cattle pasture conspicuously on land formerly -claimed by the buffalo (bison). We see pronghorns each year. A lone -coyote is the only other relatively large mammal we have logged. Check a -good mammal book and you will appreciate what lives here largely -invisible to the untrained eye: shrews, moles, bats, cottontails and two -kinds of jackrabbits, pocket gophers, prairie dogs, kangaroo rats, -voles, several kinds of mice, two kinds of ground squirrel, muskrats, -beaver, raccoons, minks, badgers, longtailed weasels, two kinds of -skunks, occasional porcupines and bobcats, white-tailed deer, and mule -deer. Consider yourself lucky if you see the swift fox, mountain lion, -and the rare black-footed ferret. - -Life abounds here in other forms less noticeable to eyes trained on the -Breeding Bird Survey: various species of amphibians, reptiles, fish, and -the numerous insects associated with grasslands. We hear perhaps too -much about rattlesnakes—western Nebraska has only the prairie rattler, -whose numbers are now much reduced. Other snakes include western -hognosed, blue racer, bullsnake, and the plains, wandering, and -red-sided garter snakes. - - - Collections of Agate Springs Fossils - - - Museums You Can Visit - -Many museums throughout the world have displays of fossils from the -Agate Fossil Beds. Very few of them actually collected their own -material. Museum curators are dedicated “horse traders” and -fossil-swapping is part of the business. When museums such as the -Carnegie Museum of Pittsburgh or the American Museum of Natural History -in New York make collections like the ones made at Agate earlier in this -century, they usually have some trading stock left over after completing -their study collections and exhibits. They then can trade an extra -_Menoceras_ slab, for example, for a dinosaur skeleton from some faraway -corner of the Earth. - -At several museums in this country you can see mounted skeletons of -several animals found at Agate, along with _Menoceras_ slabs (sections -of rock with the bones still imbedded) or models and dioramas of Agate -specimens. To the right are listed, in order of proximity to the park, -some of the museums and their specimens from Agate. - -The United States Museum of Natural History, Smithsonian Institution, -has many fossils that depict the life of the most recent 65 million -years and several murals by artist Jay H. Matternes showing the life of -each of the epochs. The Miocene mural, reproduced on pages 20-21 of this -handbook, is among these reconstructions. It depicts ancient life around -what is today known as Agate Fossil Beds National Monument. - - The Trailside Museum - Fort Robinson, Nebraska 69339. - _Menoceras_ slab, skeleton, and restoration - _Stenomylus_ skeleton on a slab, and a prepared limb - _Palaeocastor_ in a _Daemonelix_ - _Palaeocastor_ in a plaster cast - Museum of Geology, South Dakota School of Mines and Technology - Rapid City, South Dakota 57701. - _Menoceras_ slab, beautifully prepared - The Geological Museum - University of Wyoming, Laramie, Wyoming 82070. - _Menoceras_, mounted skeleton - _Stenomylus_ slab containing most of a skeleton - University of Nebraska State Museum - 101 Morrill Hall, 14th and U Streets, Lincoln, Nebraska 68508. - _Moropus_, mounted skeleton - _Palaeocastor_ skeleton in a _Daemonelix_; also, two other - _Daemonelix_ - _Menoceras_ slab - _Dinohyus_ skeleton - _Stenomylus_, a group of skeletons - Field Museum of Natural History - Roosevelt Road at Lake Shore Drive, Chicago, Illinois 60605. - _Menoceras_ slab - _Moropus_ skeleton - The University of Michigan Exhibit Museum - 1109 Geddes Rd., Ann Arbor, Michigan 48104. - _Menoceras_ slab and mounted skeleton - _Dinohyus_ eating dead Menoceras, a diorama - _Stenomylus_ skeleton and model - Carnegie Museum - 4400 Forbes Ave., Pittsburgh, Pennsylvania 15213. - _Promerycochoerus_ slab - _Menoceras_ slab and mounted skeleton - _Moropus_, mounted skeleton - _Dinohyus_, mounted skeleton - _Stenomylus_, three skeletons mounted in a group - The American Museum of Natural History - Central Park West and 79th St., New York, New York 10024. - _Moropus_ skeleton - _Menoceras_ slab and skulls, one used in a sequence showing - collecting and preparation techniques - _Dinohyus_ skull - _Stenomylus_, nine skeletons and a reconstruction of the group - in life - Museum of Comparative Zoology - Harvard University, Oxford Street, Cambridge, Massachusetts 02138. - _Menoceras_ slab - _Dinohyus_ skeleton - _Stenomylus_ skeleton - - - NPS Areas With Fossil Exhibits - -Several fossil sites in the United States are under the protection of -the National Park Service. Besides Agate, the major ones are: - - - Badlands National Park, South Dakota - - [Illustration: Badlands] - -Prominent deposits from the Oligocene Epoch, predecessor to the Miocene, -combine with a rugged, eroded landscape and abundant wildlife to make -Badlands a park where the natural processes of the past combine with -those of today. The National Park Service maintains a Fossil Exhibit -Trail at Badlands and presents fossil cleaning demonstrations. Prominent -fossils are those of ancient camels, giant pigs, sabertooth cats, -_Protoceras_, and _Brontotheres_. Mailing address: P.O. Box 6, Interior, -SD 57750. - - - Dinosaur National Monument, Colorado and Utah - - [Illustration: Dinosaur] - -The late Jurassic muds and sands of the Morrison Formation have been a -major source of dinosaur bones for more than a century. Steeply tilted -strata near Vernal, Utah, were the source of tons of bones for the -Carnegie Museum of Pittsburgh. This quarry site became the nucleus of -Dinosaur National Monument. The bone-bearing stratum has been exposed by -careful excavation, so that bones and partial skeletons of numerous -dinosaurs are exposed in high relief. The entire quarry face is covered -by a glass-walled structure that forms a large gallery. Mailing address: -4545 E. Hwy. 40, Dinosaur, CO 81610. - - - Florissant Fossil Beds National Monument, Colorado - -This site has long been famous for its fossils of insects and plants -preserved in fine-grained sediments. Specimens of _Brontothere_ indicate -an Eocene age for the deposits. Mailing address: P.O. Box 185, -Florissant, CO 80816. - - [Illustration: Florissant] - - - Fossil Butte National Monument, Wyoming - -Within the strata of this rock remnant of an ancient lake is one of the -most extensive concentrations of fossilized freshwater fish known to -science. The site is about 18 kilometers (11 miles) west of Kemmerer, -Wyoming. Mailing address: P.O. Box 592, Kemmerer, WY 83101. - - - Petrified Forest National Park, Arizona - - [Illustration: Petrified Forest] - -Here in the Late Triassic Chinle Formation are widespread deposits of -petrified logs. Some are nearly 2 meters in diameter and 60 meters long -(6.5 by 197 feet). Preserved in bright colors of opal and other -minerals, the most common trees are relatives of the living monkey -puzzle or Hawaiian star pine. Paleontologists believe many of the logs -floated to the area in Triassic rivers and became stranded. In the -museum are displays of various fossil plant species and animal fossils -from the same deposits. Mailing address: P.O. Box 2217, Petrified Forest -National Park, AZ 86028. - - - John Day Fossil Beds National Monument, Oregon - -With a total of about 5,700 hectares (14,100 acres) in several -noncontiguous units in north-central Oregon, this park provides an -extensive record of Earth history dating back at least 37 million years. -Plant and animal fossils are present in great variety. Mailing address: -HCR 82, Box 126, Kimberly, OR 97848. - - - Hagerman Fossil Beds National Monument, Idaho - -Within the banks of the Snake River are preserved the last vestiges of -late Pliocene life before the Ice Age and modern flora and fauna -appeared. Mailing address: P.O. Box 570, Hagerman, ID 83332. - - - Nearby National Parks - -While you’re in the Agate Fossil Beds area, why not see some other sites -in the National Park System? These parks offer a variety of experiences -from frontier history presentations to caving. - - -Badlands National Park is 97 kilometers (60 miles) southeast of Rapid -City, South Dakota. This wonderland of bizarre, colorful spires and -pinnacles, massive buttes, and deep gorges is open all year, though -blizzards may temporarily block roads in the winter. Campfire programs -and guided nature walks are presented. Backpackers will enjoy the park’s -wilderness area. The park has a herd of about 300 bison and some prairie -dog towns. Mailing address: P.O. Box 6, Interior, SD 57750. - - [Illustration: Devils Tower] - - -Devils Tower National Monument is 47 kilometers (29 miles) northwest of -Sundance, Wyoming. Known as Mato Tipila (Bear Lodge) to the Lakota, this -towering landmark looms over the Belle Fourche River in the northeast -corner of Wyoming. Here the Black Hills meet the plains grasslands, and -you will likely see prairie dogs, as well as other mammals and a variety -of birds. The park is open all year. Mailing address: P.O. Box 10, -Devils Tower, WY 82714. - - [Illustration: Fort Laramie] - - -Fort Laramie National Historic Site is 5 kilometers (3 miles) southwest -of Fort Laramie, Wyoming. The first fort on the site was built in 1834 -and soon became a lucrative center of the fur trade. The U.S. Army took -over in 1849, using the fort to protect the Oregon Trail. The fort was -abandoned by the Army in 1890. Several buildings are furnished as they -would have been during the Army years of the 1870s and 1880s. The park -is open all year. Mailing address: HC 72, Box 389, WY 82212. - - -Jewel Cave National Monument is located on U.S. 16, 24 kilometers (15 -miles) west of Custer, South Dakota. The cave’s name comes from the -myriads of jewel-like calcite crystals that adorn its walls. Tours are -conducted daily from mid-May through September. Tours, if any, the rest -of the year are irregular. Mailing address: RR 1, Box 60 AA, Custer, SD -57730. - - [Illustration: Mount Rushmore] - - -Mount Rushmore National Memorial is 40 kilometers (25 miles) southwest -of Rapid City, South Dakota. The mountain sculpture of Washington, -Jefferson, Theodore Roosevelt, and Lincoln is best viewed under morning -light. From June 1 to Labor Day the faces are illuminated at night. The -park is open all year. Mailing address: P.O. Box 268, Keystone, SD -57751. - - [Illustration: Scotts Bluff] - - -Scotts Bluff National Monument is 8 kilometers (5 miles) southwest of -Scottsbluff, Nebraska. This massive rock promontory rises 245 meters -(800 feet) above the valley floor, and it served as a landmark to -Indians, fur traders, and settlers traveling the Oregon Trail. It was -named for a fur trapper, Hiram Scott, and has remained a symbol of the -great overland migrations. The park is open all year. Mailing address: -P.O. Box 27, Gering, NE 69341. - - -Wind Cave National Park is 16 kilometers (10 miles) north of Hot Springs -in southwest South Dakota. Two worlds meet here: the underground world -of the cave and the life of the surface prairie. The cave gets its name -from the wind blowing into or out of the cave. Mailing address: RR 1, -Box 190, Hot Springs, SD 57747. - - - Not So Nearby National Parks - -By expanding your travel perimeter even farther beyond Agate Fossil -Beds, you can take in these other National Park System sites. - - -Bighorn Canyon National Recreation Area straddles the Montana-Wyoming -border, 67 kilometers (42 miles) from Hardin, Montana, and at Lovell, -Wyoming. Access to boat ramps and campgrounds is from both ends of the -long reservoir. Yellowtail Dam tours are given from Memorial Day to -Labor Day. The visitor centers are open all year. Mailing address: P.O. -Box 458, Fort Smith, Montana 59035. - - -Little Bighorn Battlefield National Monument is 24 kilometers (15 miles) -south of Hardin, Montana. Here on June 25, 1876, Lt. Col. George -Armstrong Custer and five 7th Cavalry companies attacked and were -surrounded and killed by Indians. Mailing address: P.O. Box 39, Crow -Agency, MT 59022. - - [Illustration: Rocky Mountain] - - -Rocky Mountain National Park is northwest of Denver and about 3 -kilometers (2 miles) west of the community of Estes Park, Colorado. The -park is one of America’s most accessible mountainous areas. Trail Ridge, -which crosses the Continental Divide, offers breathtaking views. Elk, -mule deer, bear, cougar, and bighorn sheep roam mountain crags, meadows, -and valleys. Mailing address: Estes Park, CO 80517. - - [Illustration: Theodore Roosevelt] - - -Theodore Roosevelt National Park is on Interstate 94 at Medora, North -Dakota. A separate unit is 90 kilometers (56 miles) north on U.S. 85. In -these magnificantly colored badlands along the Little Missouri River -Roosevelt had an open-range ranch and developed his practical -conservation philosophy. Both units have campgrounds. Mailing address: -P.O. Box 7, Medora, ND 58645. - - - Armchair Explorations - - - Some Books You May Want to Read - - Bartlett, Richard A., _Great Surveys of the American West_, University - of Oklahoma Press, 1962. - - Camp, Charles L., _Earth Song: A Prologue to History_, American West - Publishing Co., 1970. - - Colbert, Edwin H., _Evolution of the Vertebrates_, John Wiley and - Sons, Inc., 1969. - - Cook, Harold J., _Tales of the 04 Ranch_, University of Nebraska - Press, 1968. - - Cook, James H., _Fifty Years on the Old Frontier_, University of - Oklahoma Press, 1980. - - Gould, Stephen Jay, _Ever Since Darwin: Reflections in Natural - History_, W. W. Norton and Co., 1977. - - Howard, Robert West, _The Dawn-seekers_, Harcourt Brace Jovanovich, - 1975. - - Johnson, Kirk R. and Richard K. Stucky, _Prehistoric Journey: A - History of Life on Earth_, Roberts Rinehart, 1995. - - Lanham, Url, _The Bone Hunters_, Columbia University Press, 1973. - - Laporte, Léo F., _Evolution and the Fossil Record_, W. H. Freeman Co., - 1978. - - Larson, Robert W., _Red Cloud: Warrior-Statesman of the Lakota Sioux_, - University of Oklahoma Press, 1997. - - Mason, Stephen F., _A History of the Sciences_, Collier Books, 1970. - - Meade, Dorothy Cook, _Heart Bags & Handshakes: The Story of the Cook - Collection_, National Woodlands Pub. Co., 1994. - - Osborn, Henry F., _Cope: Master Naturalist_, Princeton University - Press, 1931. - - Paul, R. Eli, _Autobiography of Red Cloud: War Leader of the Oglalas_, - Montana Historical Society Press, 1997. - - Plate, Robert, _The Dinosaur Hunters: Othniel C. Marsh and Edward D. - Cope_, McKay Co., 1964. - - Raup, David M. and Steven M. Stanley, _Principles of Paleontology_, W. - H. Freeman Co., 1978. - - Romer, Alfred Sherwood, _Vertebrate Paleontology_, University of - Chicago Press, 1966. - - Schuchert, Charles and Clara Mae LeVene, _O.C. Marsh: Pioneer in - Paleontology_, Yale University Press, 1940. - - - Index - - _Numbers in italics refer to photographs, illustrations, charts, or - maps._ - - - A - _Aepinacodon_ _54-55_, 60 - Agate Fossil Beds National Monument 11, 14, 50; - animals at, _20-22_, 24-34, _84_; - birding at, 81, _82-83_, 85; - established, 17, 78; - geology of 23, 47-52; - museum specimen of, 38, _86-87_; - topography of, 7; - visitor information 77-80 - Agate Springs Ranch 7, 10, 17; - excavations at, 38, _39_; fossils from, _40-41_, 86-87 - Alligator _54-55_, 60 - American Museum of Natural History 14, 38, 52, 87 - _Aplodontia_ 32 - - - B - Badlands National Park, South Dakota _88_, 90 - Barbour, Erwin H. 11, 14, 38 - Big Badlands, South Dakota 49, 52 - Bighorn Canyon National Recreation Area, Montana-Wyoming 92 - Bittern, American _83_ - Blackbird, red-winged _82_ - Bone Cabin, Wyoming 48 - Breeding Bird Survey, U.S. Fish and Wildlife 81, _82-83_, 85 - Buteos (buzzard hawks) 28 - - - C - Cambrian period _46_ - Camels. _See_ _Oxydactylus_, _Stenomylus_ - Camping 78 - Carboniferous period _46_ - Carnegie Hill _12-13_, 14, 37, 77 - Carnegie Museum 14, 38, 39, _40-41_, 69, 87, 88 - Carnivores, small 32-34 - Cenozoic Era _46_, 47, 49, 52 - Chalicotheres. _See_ _Moropus_ - Cheyenne River 52 - Cleveland, Utah 48 - Colorado Plateau 49 - Como Bluff, Wyoming 48 - Cook, Eleanor Barbour 14 - Cook, Harold 10, 14, 17, 52 - Cook, James H. _6_, 8, 10-11, 14, 77; - buys Agate Springs Ranch, 7, 10; - discovers fossils, 11, 24, 38 - Cook, Kate Graham 10-11, 14 - Cook, Margaret Crozier 17 - Cook Museum of Natural History 17 - Cope, Edward Drinker _9_, 11, 14 - Coyote _84_ - Cretaceous period _46_ - Curlew, long-billed _82_ - Cuvier, Georges 42, _43_, 45 - Custer Battlefield National Monument. _See_ _Little Bighorn - Battlefield National Monument_ - - - D - _Daemonelix_ 33, _69_, 70, 86 - _Daphoenodon_ _20-21_, 22, 32, 38 - Darwin, Charles 43, _44_, 45 - Devil’s Corkscrew _76_ - Devils Tower National Monument, Wyoming _90_ - Devonian period _46_ - _Diceratherium_ 24. _See also_ _Menoceras_ - _Dinohyus_ _20-21_, 22, 30, 87 - Dinosaur National Monument, Colorado and Utah 42, 48, _88_ - Drought 35, 36, 50-51 - - - E - Ecology 53, 61-73 - _Entelodon_ 30 - Entelodont 30 - Eocene epoch 25, 27, 29, 31, _46_, 49, 53, 63, 88 - _Equus_ 63 - Excavations 38, _39_ - - - F - Field Museum of Natural History 87 - Flora 7, 10, 53, _54-59_, 60, 71-73 - Florissant Fossil Beds National Monument, Colorado 53, 88, _89_ - Folsom, New Mexico 14; - spearpoint, 17 - Fort Laramie National Historic Site, Wyoming _90_ - Fort Robinson State Park, Nebraska 50, 77 - Fossil Butte National Monument, Wyoming 89 - Fossils _38-41_, 47, 86-89 - - - G - Geological Museum, University of Wyoming 86 - Geology 35, _46_, 47-52 - Geese, Canada _82_ - Gerenuk 29 - Gering Formation 50 - Gopher, pocket _84_ - Graham, Elisha B. 10 - Graham, Mary 10-11 - Grasslands 26, 35, 51, 61, 71-72 - _Gregorymys_ 33 - Guan 28 - - - H - Hagerman Fossil Beds National Monument, Idaho 89 - Harrison Formation 23, 50, 63 - Hawk _56-57_, 60; - marsh _83_; - nighthawk _83_; - Swainson’s _81_ - Horses 62-63, _66-67_. _See also_ _Merychippus_, _Miohippus_, - _Parahippus_, _Protohippus_ - Hutton, James 45 - - - J - Jackrabbit _84_ - Jefferson, Thomas 42 - Jewel Cave National Monument, South Dakota 91 - John Day Fossil Beds National Monument, Oregon 89 - Jurassic period _46_ - - - K - Killdeer _83_ - - - L - Laboratory _40-41_ - Lamarck, Jean-Baptiste de _43_ - Laramide Revolution 49 - Linnaeus, Carolus _43_ - Little Bighorn Battlefield National Monument 92 - Lucretius (Titus Lucretius Carus) 42 - Lyell, Charles 42, 43, _45_ - - - M - Map _78_, _79_ - Marsh, Othniel C. _8_, _9_, 11 - Marsland Formation 50, 51 - Matthew, W. D. 52 - McJunkin, George 14 - Meadowlark, western _83_ - _Meniscomys_ 32-33 - _Menoceras_ 14, _20-21_, _22_, _24_, 25, 36, 38, 51, 86, 87 - _Merychippus_ 52, _58-59_, 60, 62-63 - _Merychyus_ _20-21_, 22 - Mesozoic era _46_, 47-49 - Miocene epoch _46_, 49-52, 71-73; - animals of 20-37, 62, 63, _64-69_, 70; - birds of 28 - _Miohippus_ 25-26, 27, 64, _66-67_ - Mississippi Embayment 35, 49 - Monroe Creek Formation 50 - Morrison, Colorado 48 - _Moropus_ _20-21_, 22, _29-30_, 86-87 - Mount Rushmore National Memorial, South Dakota _91_ - Museum of Comparative Zoology, Harvard University 87 - Museum of Geology, South Dakota School of Mines and Technology 86 - Museums, fossils at _86-87_. _See also_ _American Museum of - Natural History_, _Carnegie Museum_ - - - N - _Nanotragulus_ 27-28 - National Park Service 17, 88-92 - Nighthawk _83_ - _Nimravus_ 32 - Niobrara River 7, _16_, 23-24, 36, 37, 50, _54-55_, _60_ - North Platte River 52 - _Nothocyon_ 32, 33 - - - O - Oglala Sioux Indians 7, 11. _See also_ _Red Cloud_ - _Oligobunis_ 32 - Oligocene epoch 25, 31, _46_, 49, 50, 52, 53, 70, 88; - animals of 61, 63 - Opossum _54-55_, 60 - Ordovician period _46_ - _Oreodon_ 25, _54-55_, 60, 63 - Osborn, Henry F. 14, 38 - Owl, great horned _83_ - _Oxydactylus_ _20-21_, 22, 28, _56-57_, 60 - - - P - _Palaeocastor_ 14, _20-21_, 22, _33_, 64, _68-69_, 70-71, 77, 86 - _Palaeolagus_ 34 - Paleocene epoch _46_, 53 - Paleozoic era _46_, 47-48 - _Parahippus_ _20-21_, 22, _27_, _56-57_, 60, 62, 67 - Permian period _46_ - Peterson, O. A. 14, 38, 39 - Petrified Forest National Park, Arizona _89_ - Pigs 30-31 - Pine Ridge, South Dakota 52 - Pleistocene epoch 28-29, _46_, _64_, 67 - Pliocene epoch 24-25, 27, _46_, 52, 63 - _Portheus_ 48 - Precambrian era _46_ - _Promerycochoerus_ _20-21_, 22, 25, 87 - Pronghorn (artiodactyls) 63, _84_. _See also_ _Syndyoceras_ - _Protoceras_ 31 - _Protohippus_ 62, 63 - _Pseudaelurus_ 32, _58-59_, 60 - - - Q - Quaternary period _46_ - - - R - Red Cloud 9, 11 - Rhinoceros 24-25, 50, 51, 63 - Rocky Mountain National Park, Colorado 92 - Rocky Mountain Revolution 51, 52 - Runningwater Formation 51 - Rodents 32-34 - - - S - Sandpiper, upland _14_ - Scotts Bluff National Monument, Nebraska 49, _91_ - Sheep Creek Formation 52 - Silurian period _46_ - Smiley Canyon, Nebraska 50 - Snake, hognose _84_ - _Stenomylus_ 14, _20-21_, 22, _29_, 37, _39_, 50, _64-65_, 86, 87; - _hitchcocki_, 51 - Sundance Formation 48 - _Syndyoceras_ _20-21_, 22, _31_ - _Synthetoceras_ 31-32 - - - T - Teeth, high-crowned 62-63 - _Temnocyon_ 32 - Tertiary period _46_, 53 - Theodore Roosevelt National Park, North Dakota 92 - Thompson, Albert 14, 38 - Toadstool Park, Nebraska 49 - Tortoise 33-34 - Trailside Museum, Nebraska 86 - Triassic period _46_ - - - U - Uniformitarianism 42, 43, 45 - University Hill 7, _12-13_, 35; - digging at, 14; - formation of 37; - tourist facilities at, 77 - University of Nebraska State Museum 86 - - - V - Visitor information 77-80, 86-92 - Von Linne, Karl _43_ - - - W - Wallace, Alfred _45_ - White River 52; - Badlands 31; - Beds 49 - Wildflowers 7, 10 - Wind Cave National Park, South Dakota 91 - Wren, house _82_; - long-billed marsh _82_ - - - ★GPO: 1999—454-765/00504 - Reprint 1999 - - - - - National Park Service - - -The National Park Service expresses its appreciation to all those -persons who made the preparation and production of this handbook -possible. The Service also gratefully acknowledges the financial support -given this handbook project by the Oregon Trail Museum Association, a -nonprofit group that assists interpretive efforts at Agate Fossil Beds -National Monument. - - - Texts - -James R. and Laurie J. Macdonald, authors of “A Landscape Rich With -Life” in Part 2, are paleontologists who live in Sunnyvale, California, -and teach nearby. - -Doris B. Gates, writer of “Birding Along the Niobrara” in Part 3, is a -retired biology professor who lives in Chadron, Nebraska. - - - Maps - -R.R. Donnelly & Sons Co. 79. - - - Illustrations - - - Jay H. Matternes, who painted the wildlife panoramas and animal - features on the cover and in Part 2, is a paleontological - reconstruction artist who lives in Fairfax, Virginia. In Part - 2 his illustrations appear on pages 20-21, 24, 25, 27-33, - 54-59, 64-69. - American Museum of Natural History 9 Cope. - Greg Beaumont 14, 81-84. - Carnegie Museum 38-41. - Library of Congress 43-45. - James O. Milmoe 12-13, 15, 16, 76. - Peabody Museum of Natural History, Yale University 8. - All other illustrations are from the files of Agate Fossil Beds - National Monument and the National Park Service. - - - - - U.S. Department of the Interior - - -The mission of the Department of the Interior is to protect and provide -access to our Nation’s natural and cultural heritage and honor our trust -responsibilities to tribes. The National Park Service preserves -unimpaired the natural and cultural resources and values of the National -Park System for the enjoyment, education, and inspiration of this and -future generations. The National Park Service cooperates with partners -to extend the benefits of natural and cultural resource conservation and -outdoor recreation throughout this country and the world. - - - - - Agate Fossil Beds - - - _Through the remains of animals long extinct, excavated here at - this site, Agate Fossil Beds National Monument tells the story of - the Miocene Epoch—the Age of Mammals—that occurred 5 to 23 million - years ago. The scene on the front cover is from a mural by artist - Jay H. Matternes that depicts animals of the Early Miocene._ - - [Illustration: _In addition to fossils, the park has an extensive - collection of Plains Indian art and artifacts, such as this shirt - that belonged to Red Cloud._] - - - - - Transcriber’s Notes - - -—Retained publication information from the printed edition: this eBook - is public-domain in the country of publication. - -—Relocated all image captions to be immediately under the corresponding - images, removing redundant references like “preceding page”. - -—Silently corrected a few palpable typos. - -—In the text versions only, text in italics is delimited by - _underscores_. - -—Conjecturally restored one subsection of the index entry for “Agate - Springs Ranch” - - - - - - - -End of the Project Gutenberg EBook of Agate Fossil Beds National Monument, -Nebraska, by United States National Park Service - -*** END OF THIS PROJECT GUTENBERG EBOOK AGATE FOSSIL BEDS NATIONAL MONUMENT *** - -***** This file should be named 56303-0.txt or 56303-0.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/5/6/3/0/56303/ - -Produced by Stephen Hutcheson and the Online Distributed -Proofreading Team at http://www.pgdp.net - -Updated editions will replace the previous one--the old editions will -be renamed. - -Creating the works from print editions not protected by U.S. copyright -law means that no one owns a United States copyright in these works, -so the Foundation (and you!) can copy and distribute it in the United -States without permission and without paying copyright -royalties. 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