156 PROCEEDINGS OP THE PACIFIC COAST SECTIOK 



MAMMALIAN FAUNA OF THE PLEISTOCENE BEDS AT MANIX. IN THE 

 MOHAVE DESERT REGION 



BY JOHN P. BUWALDA 



( Abstract) 



A list of the mammalian forms represented in the collections obtained from 

 the lacustrine deposits at Manix, in the eastern Mohave desert region. A 

 statement of the age of the fauna and its import in establishing the date of 

 the latest deformation of that region. 



OCCURRENCE OF MAMMALIAN REMAINS AT RAN C HO LA BREA 

 BY E. C. STEONER 



(Abstract) 



In the recent excavations at Rancho la Brea it is clear that the bones occur 

 in rather deep, narrow pits; that during the accumulation of these deposits 

 the different tar pools commonly remained distinct, due to the slow exudation 

 of the tar ; that the pockets represent a gradual accumulation built up along 

 with the surrounding Pleistocene deposits. It is further shown that a number 

 of the pockets contained several tons of bones massed together representing 

 thousands of individuals and scores of species. Since the bones are found 

 only in connection with the tar pools, it is evident that their accumulation and 

 preservation was due to the presence of the tar. 



CORRELATION OF THE TERTIARY FORMATIONS OF THE PACIFIC COAST AND 

 BASIN REGIONS OF WESTERN UNITED STATES 



BY J. C. MEEEIAM 



VERTEBRATE FAUNA OF THE ORINDAN AND SIESTAN FORMATIONS 



BY J. C. MEEEIAM 



(Abstract) 



The Orindan and Siestan formations occurring in the hills immediately to 

 the east of Berkeley form the larger part of a thick accumulation of fresh- 

 water and alluvial beds resting unconformably on the marine Miocene. The 

 Orindan formation is the lower portion of these beds, and comprises a great 

 thickness of clays, shales, sands, conglomerates, and tuffs, with occasional beds 

 of limestone. The Orindan is followed by a series of igneous rocks consisting 

 mainly of andesite and basalt. The Siestan rests on the lavas covering the 

 Orindan, and is in turn covered by a volcanic series made up largely of basalt. 



The section from the base of the Orindan to the top of the lavas above the 

 Siestan contains no marine fossils. It shows scattered through it a few re- 

 mains of fresh-water mollusca and Crustacea, land mollusca, land plants, and 

 land or fresh-water vertebrates. The accumulation as a whole is evidently the 

 result of deposition in a basin which was at times occupied, at least in part, 

 by fresh water, and at other times may have received purely alluvial deposits. 



The mammalian remains known from both the Orindan and Siestan up to 

 the present time all represent forms such as might be expected in the late 

 Miocene or in the earliest Pliocene ; but it will be necessary both to have better 

 material from the Orindan and Siestan and to have well known faunas of 

 western Miocene and Pliocene for comparison before the last word on the age 

 determination can be pronounced. 



