198 



University of California Publications. 



[Geology 



THE RATTLESNAKE. 



The type specimens of the following' species are supposed to 



have been derived from the Rattlesnake beds : 



Neohipparion occidentale (Leidy)"-. 

 Neohipparion sinclairi ( Wortman) 

 Platygonus rex Marshos. 



To these should be added, from specimens in the University 

 of California collection Pliohippus supremus (Leidy), some inde- 

 terminate rhinoceros material, a large hog, a camel of the size 

 of Alticamelus alius, fragmentary remains of a smaller camel, 

 and portions of the carapace and plastron of a tortoise (Clemmys 

 hesperia Hay.) 



The known fauna of the Rattlesnake is too scanty to afford a 

 good basis for age determination or to serve satisfactorily for 

 purposes of correlation. It is evidently pre-Pleistocene, and as 

 the Rattlesnake is separated from the Mascall by a considerable 

 interval of erosion its age may be fixed with some degree of 

 probability as Pliocene. 



es ( ( jp rom ^5 ] oose gravels overlying the Cottonwood beds. ' ' Matthew. 

 Bull. Am. Mus., Vol. 12, p. 70. This reference was based on Wortman 's 

 recollection of his collections made twenty years previous to the publication 

 of Matthew 's list. Communicated by Dr. Matthew. 



03 Mr. L. S. Davis remembers collecting what he believes to be the type 

 specimen of this species from the Rattlesnake gravels. 



