l82 CALIFORNIA ACADEMY OF SCIENCES [Proc. 30 Ser. 



among those collected by Watts the following species were 

 identified by Dr. J. G. Cooper: 



Anodonta decurtata Conrad Margaritana subangulata Cooper 



Anodonta nuttaliana Lea Physa costata Newcomb 



Amnicola turbiniformis Tryon Planorbis tutnens Carpenter 



Carmifex newberryi Lea Sphaeriuni dentaiutn Hold. 

 Goniobasis occata Hinds 



Their classification as Pliocene is perhaps supported only 

 by their conformable position on the Etchegoin claj'S, but in 

 view of the fact of their fresh-water origin, the determination 

 is not conclusive. 



Similar beds are also described by Watts ^ from the vicinity 

 of McKittrick (Sec. 34, T. 30 S., R. 22 E.) where the 

 following species were obtained : 



Anodonta nuttaliana Lea 

 Carinifex newberryi Lea 

 Poinatiopsis intei'media Tryon 



It has been suggested that these beds might be correlated 

 in part or whole with the Orindan beds described by Dr. 

 Lawson^ from the Berkeley Hills and other points in Contra 

 Costa County. If such be the case their occurrence is prob- 

 ably continuous along the whole western border of the 

 Great Valley, and probably also to the north of the Straits 

 of Carquinez. 



Stratigraphic Relations. 



With few exceptions, notably that of the later sedimentary 

 beds desiffnated as the Tulare Formation, the entire collec- 

 tion of stratified rocks described in the foregoing pages is 

 essentially marine. While the coal beds of the Eocene may 

 represent a condition somewhat different, it is evident that 

 these beds are local and have not a great stratigraphic range. 



In the case of all the later series, beginning with the Creta- 

 ceous, there is a considerable uniformity of strike and dip in 

 many parts of the range. From stratigraphic evidence alone 



1 Bull. no. 3, Calif. State Min. Bur. 1894, p. 49. 



2 Bull. Dept. Geol. Univ. Calif, v. 2, pp. 371 et seq. 



