PROCEEDINGS 



OF THE 



CALIFORNIA ACADEMY OF SCIENCES 



Fourth Series 



Vol. VII, No. 7, pp. 193-196, 1 figure. July 30, 1917 



VII 

 CLIMATIC ZONES OF MARTINEZ EOCENE TIME* 



BY ROY E. DICKERSON 



Curator Department of Invertebrate Paleontology 



Strata of Martinez age occur in California in two distinct 

 basins, the San Francisco and Los Angeles basins. Of these, 

 the San Francisco basin is roughly outhned l)y the occurrence 

 at Lower Lake, Lake Co., Cal., at Martinez, on the San Fran- 

 cisco bay shore, Mt. Diabk) region, and San Pedro Point, San 

 Mateo Co., Cal The eastern extension of this Hne is influenced 

 by the character of the deposits in the vicinity of the Diablo 

 region as they were in large part laid down in waters of mod- 

 erate depth, whereas those of Lower Lake are evidently littoral 

 in the broad sense. The bases for the strand line of the Los 

 Angeles basin were determined from a study of Martinez strata 

 in the Simi hills, near Santa Susana, at Rock Creek in the 

 southern edge of the Mohave desert and in the Santa Ana 

 mountains. Although the Martinez fauna obtained from both 

 these basins has an essential unity, yet there are certain signi- 

 ficant differences which will be described later. The Martinez 

 sea, judging from absence of sediments of Lower Eocene age, 

 did not cover the great area between Mount Diablo and the 

 Tehachapi mountains. See Fig. 1. 



It is evident from the mapping that in the San Francisco 

 basin, the Tejon strand line is in general more easterly while 

 in the Los Angeles basin, this line is the more westerly. • 



Printed from the John W. Ilendrie Publication Endowment. 



July 30, 1917 



