78 



University of California Publications in Geology [Vol. 8 



The unconformity was further marked by unmistakable mollusc 

 borings at this point. The limestone contains a few species of un- 

 doubted Eocene age. The following forms have been recognized : 



Of these forms Aturia mathewsonii has been reported from both 

 the Tejon and the Martinez. The genus Aturia is wholly restricted 

 to the Eocene, Oligocene, and Miocene. Fusus mathewsonii was 

 originally described from the Tejon. It also occurs in the basal beds of 

 the Martinez north of Mount Diablo. Paphia(f) clarki, n. sp., occurs 

 in the Martinez north of Mount Diablo. Surcula claytonensis was 

 first described from the upper portion of the Tejon, north of Mount 

 Diablo in strata above the Clark, or upper vein of coal. Phacoides 

 diaboli, n. sp., found here appears to be the same species as the 

 Phacoides, n. sp., found in the Eocene beds of San Pedro Point. The 

 stratigraphic evidence, together with a fauna of undoubted Eocene 

 age, indicate that these underlying beds are Martinez. The relation- 

 ship of these Martinez beds to the Chico has not been worked out. 

 One locality south of Mount Diablo where Chico fossils were found 

 is Curry Canon. Mr. Reginald Stoner determined the following from 

 this locality : 



Trigonia evansana Baculites, sp. 



Cucullaea truncata Cinulia obliqua 



Cardium annulatum Anchura calif ornica 



Venus varians Glycimeris veatchii 



Dentalium stramineum Ammonites, n. sp. 



Cyprinella tenuis Schloenbachia chicoensis 



Dentalium cooperi 



At the locality on the ridge between Pine Canon and Little Pine 

 Canon, the thickness of Martinez exposed cannot be more than two 

 hundred to three hundred feet, as the Franciscan schists and associated 

 serpentine are found only one-eighth of a mile away, and Cretaceous 

 strata probably occur between the two. 



It is seen from this description that the Martinez exhibits some 

 lithologic differences on the north and south sides of the mountain. 

 On the north side of the mountain, the beds — about seven hundred 

 feet thick — in descending order consist of : 



Dosinia lawsoni, n. sp. 

 Phacoides diaboli, n. sp. 

 Paphia(?) clarki, n. sp. 



Teredo, sp. 



Fusus mathewsonii Gabb 

 Surcula claytonensis (Gabb) 

 Aturia mathewsonii Gabb 



Venus(?) martinezensis, n. sp. 



