OP WESTERN NORTH AMERICA. 49 



The fauna, as originally determined and subsequently (February, 

 1906) reexamined by Matthew from the very small American Museum 

 collection, is as follows: 



Lower Huerfano fauna and equivalents. 

 [X=species represented; (X)— genus represented.] 



Lower 

 Huer- 

 fano. 



Wasatch. 



Wind 

 River. 



Coryphodon sp. cf. ventanus . 

 Lambdotherium popoagicuni 



Eohippus (Pliolophus) sp 



?Phenacodus cf. wortpiani . . . 



Trigonolestes sp 



Oxysena huerfanensis 



Didymictis cf. altidens 



Viverravus cf. dawkinsianus. 



?Didelphodus 



Hyopsodus, large sp 



X 

 X 

 X 

 (?) 

 X 

 X 

 X 

 X 

 (?) 

 X 



(X) 



X 



X 

 (X) 

 ^X) 



X 



X 



X 



The Eohippus is more advanced than anything in the Wasatch, 

 but distinctly more primitive than the most primitive Orohippus of 

 the Bridger in our collections. The lower part of the Huerfano is, 

 on this showing, homotaxial with a portion of the Wind River. 



UPPER PART OF HUERFANO FORMATION; ?UINTATHERIUM ZONE. 



(Homotaxis, lower (?) Bridger.) 



West of Huerfano Canyon the so-called variegated marls, claj^s, 

 soft shales, and sands aggregate only 800 to 1,000 feet in thickness, 

 are nearly horizontal in position, and constitute the ''upper series" 

 of the typical Huerfano lake deposits of Hills. To the west of 

 Gardner all the mammal remains were found in these sands, clays, 

 and marls, varying from red, purple, gray, or green to yellow or whitish 

 in color, the upper arenaceous clays containing the richest deposits. 

 These deposits have not been examined lithologically ; it is quite 

 possible that they are largely composed of volcanic ash. Although 

 the fossils are nowhere numerous, they are all of Bridger age, namely, 

 Paldsosyops, Hyrachyus, Tillotherium, and Glyptosaurus. 



Upper Huerfano fuana and equivalents. 



Upper 

 Huer- 

 fano, 



Wasatch 



Wind 

 River. 



Bridger. 



Tillotherium sp 



Paramys 



Microsyops sp 



Patriofehs sp. ind 



?Hyrachyus small sp . . . 

 Amblypoda, n genus of? 



X 

 X 

 X 

 X 

 X 



(X) 



X 

 X 

 X 



(X) 

 X 



a The Amblypoda are represented by a tibia of small size which may have belonged to Uintatherium. 

 56092— Bull. 361—09 4 



