UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 4, No. 4, pp. 89-100, Pis. 8-1 1 ANDREW C. LAWSON, Editor 



ARC AS OF THE CALIFORNIA NEOCENE. 



BY 



Vance C. Osmont. 



CONTEXTS. 



PAGE 



Introduction 89 



Area inicrodonta Conrad 90 



Description 90 



Occurrence and Associated Fauna <M 



Area irilineata Conrad 91 



Description 91 



Occurrence and Associated Fauna 92 



Area montereyana, new species 96 



Description 90 



Occurrence and Associated Fauna 96 



Area camuloensis, new species 98 



Description 9S 



Occurrence and Associated Fauna 98 



Area canalis Conrad 99 



Description 99 



Occurrence and Associated Fauna 99 



Conclusions 99 



INTRODUCTION. 



Among' the most characteristic fossils of the California Neo- 

 cene Ihe areas have an important place. They are widely dis- 

 trihuted, both horizontally and vertically, in the geological sec- 

 tion. They seem to have been present in all parts of the region 

 and at all depths in the water. The species, being generally 

 short lived, are especially useful for age determinations. Unfor- 

 tunately the species have not been well defined or figured, and 

 some of the most characteristic ones have not been described. In 

 the following paper the writer has presented a comparison of 



