1916] 



Merriam: Fauna of Cedar Mountain Region 



163 



of the material and for subsequent assistance in packing and trans- 

 porting the collection. 



The drawings used in illustration of the Cedar Mountain fauna 

 were all prepared by Mrs. Louise Nash. 



OCCURRENCE 



As represented on plate 8, the Cedar Mountain region lies a little 

 more than fifty miles east of the western border of Nevada and near 

 the middle of the state on a north-south line. It is east and southeast 

 of Walker Lake, and northeast of the town of Mina. 



The deposits in which the mammalian fauna occurs are spread 

 over an area not less than fifteen miles in diameter, in lone Valley 

 and in Stewart Valley, but all seem to represent the same formation. 



The geology of the Cedar Mountain deposits in which the mam- 

 malian fauna occurs has been admirably discussed by J. P. Buwalda. 1 

 The Tertiary sediments of the Cedar Mountain region are considered 

 by Buwalda to represent a portion of the Esmeralda formation 

 described by Turner 2 from the Silver Peak region immediately to 

 the south. 



The Tertiary beds representing the Esmeralda formation in the 

 Cedar Mountain region consist of lacustral accumulations with inter- 

 calated beds of terrestrial origin. The formation here has a thick- 

 ness of not less than one thousand feet. 



The lacustral deposits consist in a large part of sandstones with 

 shales, cemented tuffs, conglomerates, limestones, and cherts. The 

 terrestrial beds comprise fanglomerates, sandstones, and pumiceous 

 tuffs. Within the lacustral beds at several localities are lithoid tufa 

 domes similar to those occurring in the Pleistocene deposits of Lake 

 Lahontan. 



The Esmeralda formation of the Cedar Mountain region rests in 

 very marked unconformity upon pre-Tertiary series which were greatly 

 deformed and eroded before accumulation of the Esmeralda. 



Between the Tertiary beds of the Cedar Mountain region and the 

 older, much disturbed sediments are local rhyolitic and andesitic lavas 

 markedly unconformable upon the older series, and also apparently 

 not conformable with the Esmeralda. So far as observed the rhyolite 



i Buwalda, J. P., Univ. Calif. Publ. Bull. Geol. vol. 8, pp. 335-363, pis. 

 32-38, 1914. 



^ Turner, H. W., Amer. Geol. vol. 25, p. 168, 1900. Also U. S. Geol. Surv. 

 Twenty-first Annual Report, part 2, pp. 192-224, 1900; and Bull. Geol. Soc. Amer., 

 vol. 20, p. 243, 1909. 



