1913] 



Louderback: The Monterey Series 



179 



PART I 



THE SANTA CLARA VALLEY REGION OP VENTURA 

 COUNTY AND ITS RELATIONSHIP TO THE 

 COASTAL REGION TO THE NORTH 

 AND WEST 1 



INTRODUCTION 



In the southern coastal region of California the Tertiary 

 formations are extensively developed and present many problems 

 of geological interest. Furthermore, on account of the remark- 

 able development of their petroleum contents that has taken 

 place in recent years, they have assumed a marked economic 

 interest. An understanding of the general relationships, corre- 

 spondences, and correlations of the rocks of the various districts 

 into which the region may be divided is therefore of importance 

 to the student of any of the various problems involving these 

 formations. 



As one after another of the West Coast Tertiary formations 

 has been more carefully studied there has gradually arisen what 

 may be looked upon as a standard depositional series applicable 

 to this coastal province, to which the formations in the more 

 newly studied localities are naturally compared and referred. 



During the summer of 1910 the writer had the opportunity 

 of studying the oil fields of Ventura and Los Angeles counties 

 and of comparing the formations there associated with the oil 

 with those of similar associations further north. In the reports 

 of the Geological Survey on these districts, 2 one formation name 

 previously used and originally applied in the central Coast 

 Ranges is found applied to the local Tertiary, but the associated 

 formations, both above and below, are all given new names — 



1 Presented before the Cordilleran Section, Geological Society of Amer- 

 ica, at the Berkeley meeting, April 1, 1911. 



2 Eldridge and Arnold, Bull. 309, U. S. Geol. Surv., 1907. 



