112 University of California Publications in Geology [VOL. 8 



than that of the Martinez, judging from the much greater abundance 

 of tropical forms represented in its fauna. For a discussion of the 

 Tejon climate the reader is referred to a recent paper by the writer 27 

 on the Eocene of the Marysville Buttes. 



RELATIONSHIP OF THE CHICO AND MARTINEZ FAUNAS 



The check-list given above shows that the following Chico species 

 range upward into the Martinez: Nucula truncata Gabb, Cylichna 

 costata Gabb, Dentalium cooperi Gabb, Dentalium stramineum Gabb. 

 All of these species appear practically identical with those of the 

 Chico, but unfortunately they represent genera whose species are 

 usually very persistent. Tellina cf . parilis Gabb which was found near 

 Lower Lake is nearly identical, as far as external form is concerned, 

 with T. parilis of the Chico. Meretrix(f) dalli, n. sp., is very similar 

 to M. fragilis Gabb of the Chico. Glycimeris veatchii var. major 

 (Stanton) is distinguishable from G. veatchi (Gabb) but it is evidently 

 a descendant of the Chico form. Amauropsis martinezensis, n. sp., is 

 allied to A. oviformis Gabb in the strata beneath. The Cretaceous 

 genera Ringinella and Anchura, are represented by E. pinguis Gabb, 

 A. englishi and A. gabbi, n. sp., respectively. 



This evidence indicates a much closer relationship between the 

 Eocene and the Cretaceous than is generally found. 



FAUNAL RELATIONSHIP OF THE MARTINEZ TO THE TEJON 



The relationship between the Tejon and the Martinez is shown by 

 the list given above. About twenty-five to thirty species range through 

 portions of both groups. About fifteen to twenty of these range from 

 the base of the Martinez to at least as high as the middle Tejon of 

 the Mount Diablo region, and some of these extend even to uppermost 

 Eocene at the Marysville Buttes. The following are species common 

 to both the Martinez and the Tejon: 



Schizaster lecontei Merriam Leda gabbi Conrad 



Cardium cooperi Gabb Modiolus merriami (Weaver) 



Crassatellites grandis (Gabb) Modiolus ornatus (Gabb) 



*Cuspidaria dolabraef ormis (Gabb)(?) Nucula (Acila) cf. truncata Gabb 



* Described by Gabb from his Cretaceous B (= Tejon). 



27 Dickerson, Koy E., Fauna of the Eocene at Marysville Buttes, California, 

 Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, p. 267, 1913. 



