|Tyrannosaurus. Note the bird-like feet.|
By Barnum Brown
Man written records are the chronicles of events that are confined to the later chapters of the earth's history. In comparison they are no more than a page of the unwritten history found in the rocks. This earth book is accurate in its descriptions. In many places, however, leaves are torn out and sometimes translators disagree, but it is always due to faulty interpretation. One of the most interesting of the geologic stories is that of animal life.
Conditions have been favorable for the preservation of animal remains, during the different geological periods, in only a few restricted areas where they were covered by wind-drifted matter, river and lake mud, ocean ooze or volcanic ashes. Such places are found most abundant in the Western United States east of the Rocky Mountains, where the accumulated sediments are weathered into sculptured "bad lands." Some of these bad-lands have been thoroughly explored and all surface fossils collected, for the present at least, until more are uncovered by the action of rain and wind.
Many of the most interesting of the prehistoric animals are known only from fragments, consequently news of an unexplored region is received by scientists with delight; new fields invariably turn out a few or many forms new to science, and the pleasure of discovering an unknown fossil animal is greater than vouchsafed to a successful gold prospector, for each new discovery means one more brick added to the structural knowledge of life.
Information of a new locality often comes in the most unexpected and accidental way—for example, the Hell Creek region. A few years ago Dr. W. T. Hornaday, director of the Bronx Zoological Garden, was hunting deer in a wild section of Montana, near the Missouri River, north of Miles City. In the bad-lands he saw a pile of large bones, one of which was brought home for a paper weight. His companion on that expedition, Mr. L. A. Huffman, of Miles City, took a series of fine photographs. When shown to the writer the bone was recognized as part of a horn core of an extinct reptile known as Triceratops, while the photographs showed the similarity of these bad lands to a deposit in Wyoming from which all fossil bones had been collected.
|Tyrannosaur quarry on Hell Creek|
It was, therefore, with sanguine expectations that an expedition was planned for the following season. Our outfitting point and base of supplies was to be Miles City, Mont., a point on the railroad nearest to the bad-lands, about 130 miles away. Some time was spent in obtaining team, wagon and camp equipage, for everything must be freighted to the bad lands by wagon. A teamster, familiar with the surrounding country, is easily secured in almost any Western town, and nearly every ex-cowboy says he can cook—but really does well if he succeeds in boiling water without burning it. The hardships of camping in regions remote from settlements in the West are not so great as in early pioneer days, for now practically all vegetables, fruits, butter and milk are canned. One certainly gets tired of living on bacon and ham during the hot summer, and 1poks longingly at a fat beef, but the real hardship is the water, or lack of it. During the early spring it is plentiful, but toward the last of June rains are less frequent, the creeks dry up, and water that remains in pools becomes so strongly alkaline that the surrounding banks are covered by frostlike crystals. Yet even this looks good to a thirsty bone hunter who has ridden thirty miles without a drink, and he does not hesitate to use the Western water test; that is, to throw a stick in the pool. If the stick falls over it is water, but if the stick stands up it is mud and not fit to drink.
Our destination was Jordan, not far from Hell Creek. This association of names I learned later was not due to any especial irreverence on the part of those who christened the places. Jordan was named for its founder, while the creek was undoubtedly named by some cowboy who had failed to get thru the surrounding bad-lands.
Uncle Sam has few more desirable un-surveyed sections of country left than that part of Montana lying between the Yellowstone and the Missouri rivers, which is destined someday to support a dense population. The prairies, undulating like a vast tossing sea, are covered with short grasses. Shallow depressions where buffalo wallowed and a few of their bleaching bones are the mute reminders of the vast herds that vanished before the white pioneer. Then the cattle came, and in numbers nearly equaled the buffalo. They, too, are passing rapidly ; deep-channeled roadside trails wind over the plains as far as the eye can see, marking the course of great round-up drives, but few of the large cattle outfits like the hat X, X I, and L U brands are left. These run about 20,000 each.
Now canvas-covered sheep wagons dot the landscape marking the course of the living streams and the temporary homes of the shepherds, for this is the sheep-man's country. Like the nomads of old, they roam from place to place as the grass is eaten off. The bands of 3,000 head of closely herded sheep leave the ground nearly bare as they pass over it, consequently the camp must be changed often. The tinkle, tinkle, tinkle of many bells and the incessant bleating in various keys, with the lonesome hours spent following the bands, are said to "loco" the herder; certainly it loosens his tongue when given an opportunity to talk to fellow men. His one solace is his faithful dog, whose noisy welcome sounds our approach, for he, too, is glad of a sight of new faces.
|Another view of Tyrannosaur quarry|
Five days of travel over the boundless prairies, thru such scenes, brought us to the much-talked-of Jordan, where cowboys sometimes still "shoot up the town." I was quite surprised when the three log houses nestling among the cottonwood trees on the Big Dry were first pointed out me as Jordan, for they did not at all seem as important as the name. But time works rapid changes, even so far from the railroad, for in three years a dozen houses have been built in the village. There is no church, but the saloon keeper's sister teaches a Sunday school class, thus creating a social status for the community.
From Jordan the country is rolling part of the way, but suddenly, as we cross the divide near Hell Creek, a panorama of striking beauty spreads out before us. The whole country for a hundred miles up and down the river is cut into fantastic bad-lands. Canons two and three hundred feet deep, with nearly vertical sides, and short lateral cul-de-sac, make travel by horse difficult, sometimes almost impossible.
The somberness of these denuded areas is relieved by the bright-colored banded clays, the different layers of which can often be traced for miles on the same level. Scattered pine trees cover most of the hills, while the sheltered hillside pockets are filled with junipers, and on Seven Blackfoot Creek there are groves of fir trees marking the most eastern boundary of this Pacific variety. In the valleys the courses of the streams are marked by fringing cottonwoods.
Mr. Hornaday had found the bones mentioned near the Max Seiber ranch, so it was thither that we directed our course. This is near the head of Hell Creek canon, where the stream has cut thru yellowish sepia-colored sandstone. Harder spherical or irregular shaped sandstones of various sizes are scattered thru this layer, and it is in these harder sandstones that the bones are best preserved. Often a hillside will be strewn with clusters of immense rounded stones resembling a nest of eggs.
The various layers of earth show that they were deposited more or less uniformly, by wind-drift and water, on the flood plains of a river which in times of high water overflowed its banks, depositing successive layers over the inundated area. Many shallow lakes, bayous and marshes were thus formed. In the clays representing such localities we frequently find beds of shells, many species of which are extinct, but some nearly identical with those living today; all representing a Mississippi fauna, showing that this section of country was drained by the same great river system as at present. Layers of woody material, in the form of coal, impressions of leaves, grasses, beds of seeds and sections of trees are found scattered thru the different layers in more or less abundance, especially toward the top of the bad lands, which represent a later geological period. All of these are extinct species of plants, while the genera here congregated are now widely scattered. Here are leaves of the ginkgo, native of Japan, and cones of the sequoia, or big trees, of the Pacific Coast. In the lower beds are leaves of the sabal palm that proclaim the climate subtropical at that time.
Animals lived during that period; some aquatic types fed on the rushes and liliaceous plants, remaining in the water most of the time; others fed on the tree foliage and grasses of the higher ground; still others fed on their fellows. These creatures are called dinosaurs. They form a group of extinct reptiles, mostly of large size and of strange appearance. Some evidently mired down in the marshes, and in these cases the skeletons are often nearly complete, especially in those forms whose muscles were attached to the backbone by rod-like bony cartilage. These harder tissues held the skeleton together while it was gradually being covered over. Usually, however, the bones were scattered before turning to stone, either by the action of the water, which could easily dismember the loosely articulated bones as soon as the flesh began to decay, or by the flesh-eating dinosaurs. The carnivorous creatures tore their fellows to pieces while alive, or dismembered and scattered the decaying carcasses.
These great lizards must have swarmed thru the prehistoric everglades, for their bones are scattered throughout the clays in great numbers. Most numerous of all was the great Triceratops, a strange-looking beast with an immense skull ornamented by three horns, a long one over each eye and a shorter one over the nose. Its body was protected by flat bony plates set in the skin.
Nearly as numerous as these were the Hadrosaurs, a form with duck-like mouth, long hind legs and short fore legs, the latter so small that they could not be used in walking. This was a creature suited-to- the marshes, where it fed on tender juicy plants. So well preserved are its remains that in a recently discovered specimen the impression of the skin is perfect, even giving the exact contour of the tail.
Rarest of all these strange animals are the carnivorous or flesh-eating dinosaurs, only a few specimens of which have been discovered. They probably did not frequent the marshy grounds except to capture their food hence comparatively few of their skeletons have been entombed.
In the bayous and lakes were crocodiles, gavial-like champsosaurs, turtles and numerous scaly fishes. This was the close of the zenith of reptile life, in size, if not in variety.
Sometimes the collector finds a few separate teeth, a fractured limb bone, or a vertebra of a mammal, rarest of all the animal remains. These early representatives of the dominant animals of the present day had begun long before the cretaceous period, but were still small and probably few in number. The teeth and limb bones of the largest indicate an animal no larger than a house cat, while the smallest forms were of the size of bats and mice. These remains are usually associated with fish teeth and washed fragments of larger animals where they have been drifted by some water current. The association is fortunate, for the teeth are so small that they would otherwise be overlooked if it were not for some such indication. Curiously enough, the insignificant ant is the collector's best friend in such places; their cone-shaped houses are frequently located in drift material, where teeth have been brought up with the small pebbles. Thus separated from the finer sand they are more easily seen.
|Camp on Hell Creek|
We camped on Hell Creek, near the locality found by Mr. Hornaday, and before the cook's call for dinner, had located one of the most interesting fossils ever discovered. This was Tyrannosaurus, tyrant king of the dinosaurs. High up on a hillside were a number of large, rounded sandstones. Some had tumbled down the hillside and several contained bones. Tracing these scattered fragments up the side of the hill we at last found some running into the sand. Here, then, were the bones in position where they had originally been covered before turning to stone millions of years before. Each bone in this specimen was encased in a concretion of hard, flinty, blue sandstone nearly as hard as granite.
At first the sand was soft, but as the excavation proceeded beyond frost line it was firmly cemented and so hard that a pick made but slight impression on it. As the bones were scattered and the hillside steep the undertaking became a herculean task with the means at hand; but the rare bones were those of an unknown creature, so additional help was secured, and with plows and scrapers we attacked the hill. Soon, however, the sand became too hard to be plowed, and then it was necessary to send for dynamite and blasting powder. Each cut was blasted down nearly to the bone layer and the bones taken out separately. The work of removing the upper sand or clay can be done by any one, but as soon as a bone appears only one acquainted with the details of the work, an expert, is allowed to handle them.
Although turned to stone, these bones are usually delicate and brittle, and are nearly always cracked in all directions. If any attempt were made to lift them up as found they would fall to pieces. As soon as the surface of a bone is first seen, work with heavy tools ceases, a crooked awl is used to loosen up the sand or clay, and this is brushed away with a whisk broom and soft paint brushes. After the bone is partly freed shellac is poured over it, and filtering in thru the cracks holds all the pieces together as soon as dry. Then strips of burlap dipped in plaster of paris are wound around the broken bone in all directions. When the plaster has set and dried the bone can be taken up and packed in a box for shipment.
In this specimen there were several large blocks, one that weighed forty-one hundred pounds when crated. It took four horses to transport this block to the railroad.
Part of a second season was also spent in recovering the bones of this animal, and when the excavation was finally completed a hole in the hillside had been made thirty feet long, twenty feet wide and twenty-five feet deep. Unfortunately all of its bones were not present, but enough were recovered to determine nearly all of the anatomical features. The hind limbs, now mounted in the American Museum of Natural History of New York City, measure fifteen feet from the top of the hip brine to the floor, and they were hollow, like bird bones. Each enormous foot spreads over 7 1/2 square feet of surface, and had four toes, the first rudimentary and directed to the side and backward as in birds. The contour of these foot bones bears a striking resemblance to those of birds. The fore legs were very small, vestigial in size, but powerful, and were probably used in seizing and holding. The head was massive, 49 inches in length and proportionately deep. Each powerful jaw was armed with thirteen dagger-shaped teeth having saw-blade edges, the largest five inches long. As soon as one of these teeth was broken or lost another grew up from below to take its place. Thus, under each one that is functional, six teeth are found, one above another, forming a never-ending supply. The size and length of the tail are conjectural, as only two vertebrae from that part of the body were found, but it was probably long and heavy and used to balance the weight of the body when standing. From the hips forward all the vertebrae were recovered, together with vertebral and abdominal ribs, the latter, slender rods which completed the bony circle enclosing the body cavity.
Associated with the vertebrae of another individual of this same type were a number of irregular flattened bony plates that had been embedded in the skin and formed a dermal armor similar to that of the crocodile. In life this gigantic animal stood about twenty-two feet in height and was the largest carnivorous animal that has ever lived. Contemporaneous with and possibly the chief food of Tyrannosaurus were the Triceratops, or horned lizards, the largest herbivorous animals of that time. Although protected by three horns and a skin in which were set bony plates, these sluggish creatures might easily fall a prey to the more active Tyrannosaurus, king of the period and monarch of his race.
From The Independent Magazine, September 5, 1907.