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University of California Publications in Geology [Vol. 12 



whose paper on the San Pablo fauna represents the most minute 

 anal,ysis of a Cenozoie fauna of the West Coast appearing since the 

 publication of Arnold's monograph on the San Pedro Pleistocene. As 

 yet no other palaeontological study in California has given us such 

 detailed dissection of a stratigraphic sequence with such careful 

 discussion of the significance of sequence. This work is being con- 

 tinued in the upper portion of the Miocene below the San Pablo. 

 Dr. Clark has moreover made an exhaustive study of the Oligocene 

 of middle California, and an extensive publication on this fauna is 

 now in press. He has also carried out a study of the whole Oligocene 

 fauna of the West Coast to be presented in monographic form in the 

 near future. 



The Pliocene faunal problem of California has been attacked by 

 Bruce Martin, of the University of California, who explored widely 

 over tlie West Coast, and has made two significant contributions 

 through the University of California Publications : one, a description 

 of new species, the other, a general faunal study of the Pliocene of 

 middle and northern California, appearing in 1916. The work of 

 W. A. Engiisli on the Fernando Pliocene near Newhall, and especially 

 the recent studies of J. 0. Nomland on the Jacalitos and Etchegoin 

 of the Coast Range region have advanced our knowledge of the southern 

 Pliocene considerably beyond the stage to which it was carried by the 

 excellent work of Arnold and Anderson and F. M. Anderson. Nom- 

 land 's analysis of the Etchegoin Pliocene fauna and of the wonder- 

 ful 10,000 foot section in which it is found, contributed much to 

 understanding of the faunal composition of the Pliocene and of the 

 faunal sequence. 



The Pacific Coast Province has been assumed by the writer to be 

 divisible into two major parts : the California Area and the Puget 

 Area, the latter including the region of western Washington and 

 Oregon. In the Puget region, study of invertebrate faunas is much 

 less advanced than in the California Area, due largely to the smaller 

 number of local investigations. 



Following the early work of Conrad and others, comparatively 

 little was done in the region of the northwest until the first decade 

 of the present century in which we have an important reconnaissance 

 paper by Ralph Arnold on the faunas of the Pacific Coast region 

 of the Olympic Peninsula published in a bulletin of the Geological 

 Society of America in 1905. In 1909 W. H. Dall published a large 

 and very important study on the Miocene of Astoria and Coos Bay, 



