doorway and clustered shaft, pinnacle, and finial, and tapering spire."

On a nearer approach the illusion reluctantly vanishes, and all the fancied architecture is resolved into piles of hardened clay and sand. These rise from the bottom of the vale to the height of fifty, one hundred, and two hundred feet, showing along their vertical or sloping sides the varied courses of masonry of which they are composed. In the hundreds of towers and isolated masses that rise from this vale of solitude, the order of the courses is the same; and this agrees with the arrangement in the solid walls which circumscribe the valley. A thousand storms have washed the slopes, and furrowed them into the similitude of fluted shafts and clustered columns, which, at the top, bear sometimes a brown entablature of overhanging grass, or continue upward into tower and minaret. The bottom of the vale is an earth of chalky whiteness, baked by the sun, and utterly destitute of vegetation. The water which oozes out of the foundation-wall of the prairie is brackish and unpalatable. In winter, the wind and snow rush through the lanes and corridors of this city of the dead in eddying whirls, while the withered grasses and the voiceless and motionless solitude, together with the relentless frost and never-tiring storm, make the place the realization of utter bleakness and desolation. In summer the scorching sun literally bakes the clays which have been kneaded by the frosts and thaws of spring, and the daring explorer of the scene finds no tree or shrub to shelter him from the fervid rays poured down from above, and reflected from the white walls which tower around him, and the white floor which almost blisters his feet.

But the most impressive feature of the scene is the multitude of fossil bones which appear built into the massive masonry of this mimic architecture. The wearing and

crumbling of the elements roll them out of their long resting-places, and they lie strewn over the bottom of the valley. The traveler feels like one walking upon the floor of a long-deserted and ruined vault. Skulls, and jaws, and teeth, and thigh-bones lie scattered around. Death has indeed held carnival here, and this is the deserted scene of his ghastly repast. But what long ages have glided by since these flesh-covered bones were slain and gathered to the charnel-house! Scarcely a form familiar to the anatomist reveals itself. Here are, indeed, the forms of turtles, large and small, with all the sutures of their protecting carapaces distinctly preserved; but, though turtles, they are unknown species, and some attain a size which, in their present condition, must weigh nearly a ton. Here lie the bones of rhinoceroses-known certainly by their teeth-but different from any existing species. As for the rest of these remains, we do not even know the genera to which they belonged. They present us with strange combinations of characters. One seems intermediate between a tapir and a rhinoceros, while the canine and incisor teeth ally it likewise with the horse. One of the commonest skulls has the grinding teeth of the elk and deer, and the canines of a hog. It evidently belonged to a race which lived both on flesh and vegetables, and yet chewed the cud like our cloven-footed grazers. This has been named Oreodon. One of the most wonderful of the beings entombed here is the Titanotherium, first discovered by Dr. Prout, of St. Louis. It somewhat resembles a hornless rhinoceros, but is much more massive in its proportions. One of the jaws seen by Dr. Evans had a length of five feet along the crowns of the teeth, and the skeleton of another individual was eighteen and a half feet in length and nine feet in height. Of all the relics uncovered in this ancient cemetery, it is remarkable that but one carnivorous quadruped

has been noticed. The fauna of the period was eminently characterized by the presence of pachyderms and ruminants, and this in the same age when Europe was populated by a large admixture of the higher carnivores. I said this valley of death has the appearance of a subsidence in the wide extended plain. The suggestion is so natural that one almost irresistibly regards it as a vast sunken grave, where the slain of a geological convulsion have been gathered together and decently entombed, and the earth has at last settled down upon their crumbling remains. A better judgment, however, discovers the valley to be the work of excavating waters. Gigantic as the scale of such digging must appear, the geologist is acquainted with other examples immeasurably more sublime. They belong to the phenomena of the Post-Tertiary Age. These towers, then, have not been built up, but have been left in relief, like the figures on the sculptor's marble. Torrents of rain have wielded the instruments that have fashioned the Titanic architecture.

From this Golgotha, if we wend our way northward some hundreds of miles nearer the sources of the Missouri, we find ourselves standing again upon the deposits of a vast inland sea-a sea which was still remaining when the Bad Lands were drained. Around the shores of this far northern basin of water lived, in a later age, the rhinoceros, the elephant, the mastodon, the camel, the horse, the beaver, the wild-cat, the wolf, the land tortoise, and other genera of quadrupeds now extinct. In this lake the Missouri took its rise, while the Yellowstone and other rivers poured into it the drainage of the region beyond, and transported the relics of then existing races, with other sediments, to the burial-place from which they have recently been exhumed.

It gives me great pleasure to make known to the reader

that we are indebted for our knowledge of the details of the geology of these remote and wilderness regions to the energy and science of two young geologists, Messrs. Meek and Hayden, and especially to Mr. F. B. Meek, for the production of paleontological results which vie in thoroughness and exactitude with the best work ever done in any country. In the department of mammalian paleontology Dr. Leidy is our great authority-the Owen of America. These regions were first visited in 1850 by Mr. Thaddeus Culbertson, under the joint auspices of the Smithsonian Institution and his brother Alexander. Later researches were instituted by Professor James Hall, and by Dr. D. D. Owen while in charge of the geological survey of the Northwest, under the auspices of the general government.

Such are some of the phenomena of the Age of Mammals. It was an interval of time when, on all sides of the globe, progressive improvements had brought our earth to a condition suited for higher existences, and the reptiles which reigned in the preceding age were beckoned into the background or driven to extinction. Who that has observed the indications of gradual but systematic advance in animal forms through the ages of the world can resist the conviction that man was contemplated as the termination of the perfecting series?

It is a curious fact that so many genera now extinct from the continent, but living in other quarters of the globe, were once abundant on the plains of North America. Various species of the horse have dwelt here for ages, and the question reasonably arises whether the wild horses of the Pampas may not have been indigenous. Here, too, the camel found a suitable home; but he has disappeared before the intellect dawned which could domesticate him and utilize his instincts. On the Oriental continent the higher types of quadrupeds were now exist

ing, and it looked as if the apex of improvement would. first be reached in that quarter of the world.

The uplift of the American and European continents to

Fig. 79. D. D. Owen.

their present levels marked the close of the Tertiary Age. Europe had been an archipelago; but America had long possessed its destined outline, and lacked only the belt which was now added along the two oceans and the Gulf. The continent was now complete. What next could ensue but the creation of man, and the final consummation of the grand work of creation? Human judgment would now have proceeded to the finishing stroke; but Infinite Wis