56 



University of California Publications in Geology [Vol. 11 



The writer 7 formerly accepted the term Astoria as a general name 

 for the marine Oligocene of the West Coast and applied the same to 

 the so-called Oligocene beds of middle California, but after visiting 

 the type section of the Astoria in the summer of 1917, it is his con- 

 clusion that this name should not be used for the marine Oligocene 

 of the West Coast. Some of the reasons for this are as follows : The 

 most fossiliferous portion of the type section of the Astoria, the part 

 from which Conrad undoubtedly obtained the most of his fossils (see 

 review of literature on page 57) is the upper sandstones, which are 

 apparently Lower Miocene in age. The black shales below this fossil- 

 iferous sandstone have been referred to the Oligocene by Dall. 8a Appar- 

 ently this age determination was based principally upon the presence 

 of Aturia angustata Conrad in the lower beds, the genus Aturia being 

 taken as characteristic of the Oligocene. One other species, which 

 is probably characteristic of the Oligocene, was listed from these 

 beds; that is Miopleiona indurata Conrad. The genus Aturia is now 

 known to be present in the Lower Miocene of California. F. M. 

 Anderson reports finding it in the Astoria sandstones mentioned 

 above. At the present time the outcrops of these lower shales, from 

 which originally the so-called Oligocene fossils were obtained, have 

 been covered by sand which was pumped in from the river during 

 the dredging of the channel and it is impossible to get more faunal 

 evidence as to the age of the beds. Under the circumstances it would 

 seem best not to use the name Astoria as a general name for the marine 

 West Coast Oligocene. 



Both names, Clallam and San Lorenzo, were first used as forma- 

 tional names by Arnold- '' in the year 1916 ; the latter name, however, 

 precedes the former by several months and should therefore have 

 preference in use. 



ACKNOWLEDGMENTS 



The writer is especially indebted to Professor J. C. Merriam, who 

 has made possible the work of which the results are presented in this 

 paper ; he is also indebted to him for many suggestions and criticisms. 



Acknowledgment is due to F. M. Anderson and Dr. R. E. Dicker- 

 son, curators of Palaeontology of the California Academy of Sciences, 



' Clark, B. L., Astoria series, Oligocene, in the region of Mount Diablo, Middle 

 California, Bull. Geol. Soe. Amer., vol. 28, pp. 227-229, 1917. 



s« Dall, W. H., The Miocene of Astoria and Coos Bay, Oregon, U. S. Geol. 

 Surv., Prof, paper 59, p. 9, 1909. 



86 Arnold, Ralph, Tertiary and Quaternary pectens of California, U. S. Geol. 

 Surv., Prof, paper 47, pp. 15-16, March, 1906; Geologic reconnaissance of coast 

 of Olympic Peninsula, Bull. Geol. Soc. Amer., vol. 17, p. 461, September, 1906. 



