THE EOCENE OF EUROPE AND NORTH AMERICA 



135 



by Cope (1884), is distinguished by its relatively elongate head, very slender 

 limbs and digits, and the marked simplicity of its grinding teeth. The 

 horse of the Huerfano country appears (Cockerell) to correspond with this 



Fig. 45. — Tlie Wind Kiver Eocene four-toed horse, or Eohippus. As a forest-living form 

 the animal is represented as spotted. The indication of a short mane is entirely conjectural. 

 After original by Charles R. Knight in the American Museum of Natural History. 



species both in its measurements and in the simple character of the crowns 

 of its grinding teeth. 



The lophiodonts are still represented by the Wasatch Heptodon, a slender- 

 limbed animal. 



Tapirs have not yet been discovered, but they undoubtedly existed at 

 this time. 



The family of hyracodonts makes its first appearance here, its presence 

 being indicated by a single specimen of the genus Hyrachyus. 



Fishes of the Green River Shales and Other Eocene Formations^ 



While the terrestrial life of the close of the Lower Eocene is so well por- 

 trayed in the Wind River Formation, the fluviatile, lacustrine, and plant life 

 is equally well kno^\^l through the shale deposits in the Green River Lake 

 to the south (Fig. 35). 



1 Cope, E. D., The Vertebrata of the Tertiary Formations of the West. 

 Surv. Terr., Vol. Ill, 1883 (1884). 



Rept. U.S. Geol. 



