UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 8, No. 15, pp. 299-304, pi. 29 Issued December 10, 1914 



NEW MOLLUSCAN SPECIES FROM THE 

 MARTINEZ EOCENE OF SOUTHERN 

 CALIFORNIA 



BY 



ROY E. DICKEKSON 



CONTENTS 



PAGE 



Introduction 299 



Description of New Species 300 



Crassatellites brainerdi, n. sp 300 



Saxidomus(f) noblei, n. sp 300 



Cerithium butterworthi, n. sp 301 



Molopophorus( ?) howardi, n. sp. 301 



Natica pinyonensis, n. sp 302 



INTRODUCTION 



The species described in the following note were all obtained from 

 the Martinez of southern California. Geographically, the Martinez of 

 southern California is separated from that of the San Francisco Bay 

 region by a distance of six or seven degrees of latitude. Although 

 there are two distinct basins of deposition, 1 the San Francisco Basin 

 and the Los Angeles Basin, there is only one Martinez fauna, an 

 assemblage of forms with unique characters. 



The collections obtained from the Santa Ana Mountains and from 

 the southern rim of the Mohave Desert at Rock Creek show a faunal 

 unity with those of the San Francisco Basin. Climatic influences due 

 to difference in latitude would be expected to produce some faunal 

 differences between the San Francisco and Los Angeles basins if the 



i Dickerson, R. F., Fauna of the Martinez Eocene of California, Univ. Calif. 

 Publ. Bull. Dept. Geo!., vol. 8, pp. 61-180, 1914. 



