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University of Calif ornw PxCbUcatio-ns in Geology [Vol. 12 



Nevada, and added to our knowledge of the Jurassic and Triassic 

 faunas. Following the discovery of a most extraordinary section 

 of early ]\Iesozoie rocks in Shasta County, California, by H. "W. 

 Fairbanks, and the recognition of the unusually well-preserved 

 Triassic remains in this section. Professor Smith began an epoch- 

 making series of studies on the West American Triassic. This investi- 

 gation, initiated in studies of the upper division of the Triassic of 

 northern California, was extended to the middle and lower Triassic 

 of Nevada and Idaho. The results of these researches have given us 

 a monumental work covering the most significant series of Triassic 

 deposits of the Western Hemisphere, and have also given us one of 

 the most important contributions to our knowledge of the Triassic 

 faunas and of the early Mesozoic Cephalopoda in the whole field of 

 palaeontological literature. 



Following the studies of Professor Smith on the earlier rocks of 

 the California section came the work of G. H. Ashley of Stanford 

 University on the Tertiary faunas, and that of Ralph Arnold of 

 Stanford University on the Pleistocene of the San Pedro region. 

 Arnold's study of tlie Pleistocene, beginning with the first assembling 

 of material by Delos Arnold, made a very significant addition to 

 our knowledge of the latest faunas of the Cenozoic, and furnished the 

 basis for study of the whole marine Pleistocene of the Pacific Coast 

 region. Arnold's study of the Pleistocene fauna was followed at 

 Stanford University and later on in the CTeological Survey by investi- 

 gations covering especially the middle and later Tertiary of southern 

 California. Arnold's paper on the Tertiary and Quaternary Pectens 

 of California represents the most important studj' of a group of 

 Tertiary invertebrates on the West Coast published up to tlie present 

 time. Numerous papers by Arnold, appearing mainly in the bulletins 

 of the United States Geological Survey, and representing the results 

 of excellent work on the oil producing formations of California, 

 include studies of the Oligocene, lower, middle, and upper Miocene, 

 the Pliocene, and the Pleistocene. These publications register a 

 distinct advance in study of Tertiary faunal sequence and in our 

 knowledge of the composition of the Tertiary faunas of the Pacific 

 Coast. Certain papers by Arnold were in part published with the 

 cooperation of George H. Eldridge, geologist of the Geological Survey, 

 and later with Robert Anderson, of the Geological Survey. 



Beginning with the second period and continuing up to the present 

 time, important investigations were carried on by F. M. Anderson 



