GEOLOGICAL SURVEY OF THE TERRITORIES. 105 



skinned monsters could wallow at pleasure. As we pass higher up in 

 the sediments, we find the remains of a great variety of land animals 

 mingled with those that were aquatic in their nature. In a bed of flesh- 

 colored marl which is visible for a great distance, like a broad band in 

 the sides of these washed hills, thousands of turtles were imbedded, and 

 are preserved to the present time with surprising perfection, the hard 

 portions of them being as complete as when they were swimming about 

 in these tertiary waters hundreds of thousands 'of years ago. They 

 vary in size from an inch or two in length across the back to three or 

 four feet. But one species has ever been discovered in this basin, and 

 so far as we know these reptiles made up in numbers what they lacked 

 in variety. Associated with the remains of the turtles, are those of a 

 number of ruminants, all belonging to extinct genera, and possessing 

 peculiar characters which ally them to the deer and the hog. Indeed, 

 Dr. Leidy calls them ruminating hogs. Like the domestic species, they 

 were provided with cutting teeth and canines, but the grinding teeth 

 are constructed after the same pattern as those of all living ruminants. 

 The feet of these animals were also provided with four toes as in the 

 hog, and none of them possessed horns or antlers. They appear to 

 have existed in immense numbers, and to have lived in great herds like 

 the bison of the West. Remains of more than seven hundred individuals 

 of one species have been already studied and described by Dr. Leidy. 

 Their enemies were numerous wolves, hysenodons and saber-tooth tigers. 



If we pass for a moment southward into the valleys of the Niobrara 

 and Loup Fork, we shall find a fauna closely allied, yet entirely distinct 

 from the one on White River, and plainly intermediate between that of 

 the latter and of the present period; one appears to have lived during 

 the middle or miocene tertiary period, and the other at a later time in 

 what is called the pliocene. In the later fauna were the remains of a 

 number of species of extinct camels, one of which was of the size of the 

 Arabian camel, a second about two-thirds as large, also a smaller one. 

 The only animals akin to the camels at the present time in the western 

 hemisphere are the llama and its allies in South America. Not less inter- 

 esting are the remains of a great variety of forms of the horse family, 

 one of which was about as large as the ordinary domestic animal, and 

 the smallest not more than two or two and a half feet in height, with 

 every intermediate grade in size. There was still another animal allied 

 to the horse, about the size of a Newfoundland dog, which was provided 

 with three hoofs to each foot, though the lateral hoofs were rudimental. 

 Although no horses were known to exist on this continent prior to its 

 discovery by Europeans, yet Dr. Leidy has shown that before the age of 

 man this was emphatically the country of horses. Dr. Leidy has re- 

 ported twenty-seven species of the horse family which are known to have 

 lived on this continent prior to the advent of man — about three times 

 as many as are now found living throughout the world. 



Among the carnivores were several foxes and wolves, one of which 

 was larger than any now living ; three species of Hysenodon — animals 

 whose teeth indicate that they were of remarkably rapacious habits ; 

 also five animals of the cat tribe were found, one about the size of a 

 small panther, and another as large as the largest wolf. Several of the 

 skulls of the tiger-like animals exhibited the marks of terrible conflicts 

 with the cotemporary Hysenodons. 



Among the rodents were a porcupine, small beaver, rabbit, mouse, &c. 



The pachyderms, or thick-skinned animals, were quite numerous and 

 of great interest, from the fact that none of them are living on this 

 continent at the present time, and yet here we find the remains of sev- 



