The Tertiary Formations of the 



[March, 



190 



what greater. The Truckee beds of Oregon have, according to 

 Marsh, a depth of from 3000 to 4000 feet, and King estimates the 

 j deposit exposed in the Hawsoh 



, Nevada, at 2300 feet. 1 

 deposit exposed 

 in the region of the Cajon pass, 

 Southern California, is suspect- 

 ed, by King, to belong to the 



% J 



H 



6 The fauna of this epoch is 



1 widely different from that of the 



"g Eocene in its more modern char- 



E acteristics. These are the pres- 



1 ence of various types of Rodentia, 

 •S of true Carnivora, of Dicotylidse, 

 il Elotherium, Oreodontidce, Poebrc- 

 4 therium and Rhinocerontidce. All 

 o the especially Eocene groups are 

 £ absent, except Leptictidce and a 

 g few Hycenodontid<z. These give 

 E it a more ancient character than 

 o the Miocenes generally, so that 

 J it is frequently referred to as 

 « " Oligocene." 



% The following diagram repre- 



«* sents without much detail, the 



*? section in Eastern Colorado, 



^ along the Horse Tail creek, from 



2 the Chalk bluffs southward. 



At both localities the lower 



beds carry the bones of the 



' gigantic Menodontidcs, Meno- 



^~JJ k Y dus in Nebraska, and Symboro- 



5 I y don with Menodns in Colorado. 



S . g ' 1 But few other types occur in 



3 | 5 this bed in Colorado, the great 



lumber of genera and species being found in bed B, in which 



: did not discover any fragments of Chalk otheriida among a large 



»L. c p. 423; i.e., p. 4'S. 



