220 GEOLOGY. 



um had a long thigh, free from the body, a forefoot capable of be- 

 ing set down flat, and a form of lower iaw and teeth, similar to 

 that of the lower modern monkeys. The form of the humerus and 

 its relative length to the femur, resembles that of the lemurs. * * 

 " The greatest difference is that of the increased number of teeth, 

 which related them in this respect to the ancient carnivora and un- 

 gulata," all of which had more teeth than their modern congeners. 

 (Cope). The genus Anaptomorphus represents a' group more nearly 

 related to the existing types of Madagascar and South Africa. 

 None of these quadrumana of the Fort Bridger Group are typical 

 forms, and all are much more generalized than existing families.* 



The above species represent only a very small number of the 

 extinct species found in this group, but they will serve to give some 

 idea of the remarkable life that flourished during those times 

 times " when the existing orders of the mammalia were yet in pro- 

 cess of differentiation, and were scarcely distinctly defined." 



UINTA GROUP. 



South of the Uinta Mountains there is a small group of Ter- 

 tiaries, about five hundred feet thick, which constitute the closing 

 deposits of this period. They have been called the Uinta Group 

 by King. The materials at the bottom are gritty, rough conglom- 

 erates, shading upward into finer grained sandstone, and at certain 

 points into beds of creamy, impure limestone. "The strata seem 

 to form an unbroken line from the region of the Wasatch east- 

 ward through the length of Uinta Valley, across Green River, 

 into the valley of tha White River. The animal remains which 

 are. found in this group, especially in White River Valley, belong 

 to a more advanced Eocene period than the Bridger series. They 

 contain sonTfc forms approximating to the lowest Miocene types." 

 (King.) It is not improbable that these beds represent the transition 

 period between the Eocene and Miocene. Among the important 

 vertebrates of this series are the following: 



Hyopsodus gracilis was a small animal, related in many of its 

 characters to the hog family. It was of small size, and retained 

 some tapiroid elements. Epihippus Uintensis and E. gracilis were 

 small, horse-like animals of this period, closely related to the oro- 

 hippus of the Bridger beds, but showing a structure approximat- 

 ing to the Mesohippus of the next or lowest Miocene period: 



*For a full technical description of the extinct mammalian species of the Eocene of the 

 Rocky Mountains, the reader is referred to the reports of Leidy, Marsh and Cope. 



