from Meadoiv Valley Region, S. Nevada. 257 



very incomplete faunal representations occurring in the 

 later Cenozoic sediments of the Meadow Valley region 

 suggests that the Panaca beds and the Muddy Valley 

 deposits are not of same age. Furthermore, the beds in 

 Meadow Valley appear to be younger than those of 

 Muddy Valley in which fossil vertebrates have been 

 found. The occurrence of a large type of horse in the 

 Panaca beds favors the belief that these deposits are not 

 earlier in age than Pliocene, while the presence of a rhi- 

 noceros, possibly the genus Teleoceras, indicates a period 

 antecedent to the Pleistocene. The collection of ver- 

 tebrate remains from Muddy Valley is not large enough 

 to permit definite assertion as to age of the Muddy Valley 

 deposits. If the single incisor tooth belongs to a horse 

 related to Merychippus or to a closely allied form the sug- 

 gestion may be advanced that the Muddy Valley beds are 

 Miocene in age. Information obtained from a study of 

 the camel remains appears conformable to this view. 



Description of Vertebrate Remains. 

 Panaca Beds, Meadow Valley, Nevada. 



PlioJbippusl, sp. 



An unworn and fragmentary tooth, No. 24094,^ fig. 2, 

 locality 3548,^ measures approximately 14mm. in trans- 

 verse diameter across the hypoconid. This measurement 

 does not include the thickness of the outer layer of 

 cement. 



Elements of the limbs secured at locality 3547 are 

 shown in figs. 3 to 6. The limb materials indicate forms 

 larger than species of Pliohippus from the Lower 

 Pliocene of western North America. They approach in 

 size comparable structures of the Pleistocene Equus. 

 In specimens such as the median metapodial {^g. 4) and 

 the phalanges of digit 3 (figs. 5 and 6) a size is shown 

 which approximates closely that of limb elements of Plio- 

 hippus proversus from the Upper Etchegoin Pliocene of 

 California. 



^ Accession numbers refer to specimens in the collections of the Depart- 

 ment of Palaeontology, University of California. 



® University of California collecting localities. See descriptive list of 

 localities near the end of this paper. 



