Vol. 6] Merriam: Virgin Valley and Thousand Creek. 



203 



with the collections which are commonly brought together in 

 most of the series of mammal beds which have been investigated 

 in this country. In Virgin Valley the number of localities where 

 even fragments of bone are common is small. In the Thousand 

 Creek Basin loose bones are quite abundant in many places. 



In all of the exposures visited in this region the material 

 consists almost entirely of scattered remains. Neither complete 

 skeletons nor skulls could lie obtained, though most careful search 

 was made for them. Even when specimens were obtained in place 

 in the rock they were found to consist entirely of isolated parts. 

 There seems to be no question but that the bones were generally 

 widely scattered, and usually in an advanced stage of disintegra- 

 tion before they were finally buried, which may be interpreted 

 as a suggestion that the deposits represent in a large part dry 

 land accumulations rather than those formed in lakes or swamps. 



In the first publication of results of the work in the mammal- 

 bearing beds of northwestern Nevada, the faunas of Virgin Valley 

 and Thousand Creek were referred to collectively under the name 

 of Virgin Valley fauna. More recent study has shown that the 

 faunas of the formations at Virgin Valley and Thousand Creek 

 are very different, and it is desirable to consider them separately 

 before entering upon a discussion of their relative age. 



After completion of the following paper it was the writer's 

 privilege to compare the fauna here described with the most 

 nearly related forms represented in other museums. For the 

 free use of specimens desired for comparison, and for courtesies 

 extended in the course of this examination, the writer is par- 

 ticularly indebted to Mr. J. W. Gidley and Mr. C. W. Gilmore 

 of the National Museum ; to Professor Henry F. Osborn, Dr. W. 

 D. Matthew, and Mr. Walter Granger, of the American Museum 

 of Natural History ; and to Dr. W. J. Holland of the Carnegie 

 Museum. 



All of the drawings used in illustration of this paper were 

 prepared by Mrs. Louise Nash. 



