1914] Dickerson : Fauna of the Martinez Eocene of California 77 



beds were deposited. At Benicia an entire section of Martinez 

 appears to be present, and in the middle of the section forms else- 

 where associated with Trochocyathus zitteli are found in beds which 

 were not deposited in deep water, as is shown by the absence of 

 Trochocyathus zitteli and Schizaster lecontei. As none of the above- 

 mentioned forms occur here, difference in age appears to be the 

 principal cause of the faunal differences. 



Martinez and Tejon South op Mount Diablo 



During the field work of the last two University summer classes in 

 palaeontology we did not succeed in recognizing the Martinez group 

 south of Mount Diablo until the collections were correctly determined. 

 The base of the Tejon was found to be in unconformable contact with 

 the underlying beds in three different places six or more miles apart. 

 In one locality (University of California Locality 1308), the Tejon 

 rests unconformably on a gray limestone of Martinez age, in another 

 locality upon a dark gray sandstone of Chico age. 



In a locality on Little Pine Creek an angular unconformity was 

 observed between the overlying Tejon, strike N 20° W, dip 7° S, and 

 the underlying Chico strata, strike N 20° W, dip 7° N. On the divide 

 between Pine and Curry canons an angular unconformity between the 

 Chico and the Tejon was recognized, and mollusc borings were noted. 

 This unconformable contact was traced for over four miles east of this 

 divide. 



The underlying Chico yielded only fragments of Inoce ramus, but 

 the basal beds of the Tejon are very fossiliferous in many places. At 

 a locality on the ridge between Little Pine Creek and Pine Canon 

 (SE y 4 of NE V4 Sec. 4, T. 1 S, R. 1 W, M. D. B. & M.) both the 

 Tejon and underlying limestone are fossiliferous. The following 

 partial list shows the fauna which was found in the beds of the Tejon 

 a hundred and fifty to two hundred feet above the base. 



Solen parallelus Gabb Pecten, sp. 



Venericardia planicosta Lamarck Psammobia hornii (Gabb) 



Meretrix hornii Gabb Fusas mathewsonii Gabb 



Glycimeris, sp. Spirog]yphus( ?), sp. 



Leda gabbi Conrad Cylichna costata Gabb 



Cardium breweri Gabb Eimella canalifera Gabb 



Tapes conradiana Gabb Amauropsis alveata Gabb 



Tellina(?), sp. Fusus(?), sp. 



Aeila, sp. Surcula, sp. 



