1916] Merriam: Fauna of Cedar Mountain Region 171 



In comparison with the Thousand Creek and Rattlesnake Pliocene, 

 the Cedar Mountain shows a wide difference in the horses and 

 camels. The presence of HypoJiippus and Merychippus with two 

 species of Merycoclus in the Cedar Mountain fauna indicates a much 

 earlier stage than that of either the Thousand Creek or Rattlesnake, 

 before the deposition of which these genera had disappeared. 



Table Illustrating Eelative Age op the Cedar Mountain Fauna Compared 

 with Other Faunas op the Great Basin Province 



, Columbia and 

 T,me scale | Middle Basin areas 



Mohave area 



Pliocene 



Upper 



Thousand Creek 

 Rattlesnake 



Eicardo 



Middle 



Lower 



Miocene 



Upper 



Cedar Mountain 

 Mascall 



Columbia Lava 



Barstow 



Middle 



Lower 



Relation of Cedar Mountain Fauna to that of the American Terti- 

 ary East of the Great Basin. — The age of the Cedar Mountain fauna 

 is best determined when this assemblage is considered in conjunction 

 with other like faunas of the Great Basin region. Considering the 

 similarity of this fauna to that of the Barstow beds, and the relation 

 of the latter to the Upper Miocene Santa Fe fauna of northern New 

 Mexico, there can be little doubt of the relation of the Cedar Mountain 

 to the Upper Miocene. 



Compared directly with the Santa Fe fauna, the Cedar Mountain 

 mammals in some respects show a closer resemblance than do those 

 of the Barstow. While the large aelurodons of the Santa Fe are 

 not as yet known in the Cedar Mountain, there is a noticeable simi- 

 larity in the camels, in the merycodonts, and in the presence of 

 rhinoceroses, the last group being absent from the Barstow. 



The Cedar Mountain fauna resembles that of the Upper Miocene 

 or Lower Pliocene Republican River beds of the northwestern Kansas 

 to a considerable extent, but seems less advanced in the canids, 

 which are exclusively large specialized forms at Republican River. 

 The Snake Creek fauna of western Nebraska also shows an interesting 



