Mammals 1 7 



be hard to imagine. Several years ago Mr. G. T. Bruce found in 

 Cuchara sandstone of the Huerfano four well preserved teeth, 

 which we found to belong to Eohippus, — the name means horse 

 of the dawn. Later, Miss Louise Lacy found Eohippus teeth on 

 a small hill five miles from Rifle. These remains pertain to an 

 animal barely a foot high at the shoulder, looking something like a 

 small dog. It had four toes on the front feet and three on the 

 hind, a reduction from the primitive number of five toes on each 

 foot. The artist C. R. Knight, trying to picture it as in life, 

 represents it as spotted, but this is of course conjectural. It was 

 at all events a forest-living animal, with feet adapted to soft 

 ground. Why should this be called the horse of the dawn? It 

 was no more a horse than a monkey is a man; it does not even 

 belong to the same subfamily (Equinae) as the modern horse. 

 Yet between this creature and the true horse we have a series, 

 so nearly bridging the great gap that naturalists see in the Eohip- 

 pus, if not an actual ancestor of the horse, at any rate the repre- 

 sentative of a group from which the latter must have come. A 

 much later and more advanced type, the Parahippus, was found 

 fossil at Troublesome and on Pawnee Creek. In all, about seven- 

 teen species of fossil Equidae, members of the horse family, have 

 been discovered in Colorado, but before the time of Columbus 

 this race of animals was apparently quite extinct in America. 

 The wild horses mentioned in American history were the progeny 

 of the domesticated animals run wild.* 



The Elephantidae or elephants, coming from the Old World 

 by way of what is now Bering Strait, reached Colorado during 

 the Miocene. In 1 923 Osborn described a species (Rhynchotherium 

 rectidens) from the Middle Miocene near Pawnee Buttes. It was 

 based on the upper tusks. The year before, Harold Cook de- 

 scribed two species of the Mastodon group, Trilophodon hicksi 

 and T. paladentatus, from a despoit near Wray, Yuma County. 

 The specimens, consisting of lower jaws, are in the Colorado 

 Museum at Denver. Rhynchotherium is peculiar for the fact that 

 the end of the lower jaw is directed downward, perhaps to enable 

 the animal more readily to uproot trees with its lower tusks. In 

 Trilophodon this is much less conspicuous, though there is a 



♦Species of true Equus (E. complicatus and E. laurentius) did however exist in Colorado 

 in Pleistocene times (Hay, 1924). 



