1912] Clark: Neocene Section at Kirker Pass 59 



petrographic similarity. No fossils have been found in these 

 tuffs at Kirker Pass, and it is a question whether they are land 

 or water deposits. 



Orindan 



Above the Pinole Tuff is a series of light-yellow to gray, 

 medium-fine sandstones, and clays. In this region it is difficult 

 to get good outcrops in these beds, and the writer has given very 

 little attention to them. They are provisionally called Orindan, 

 chiefly because of their stratigraphic position. These beds have 

 been folded with all the other formations, and dip gently to 

 the northeast. They extend out into the valley, where they are 

 covered with terrace material. 



General Section 

 General Statement of Section as seen about One Mile to the West 



of Kirker Creek 



Orindan 



Pinole Tuff 



Yellow sandstones and clays. 



{Tuff with gravel and sand. 

 Basalt flow. 

 Massive tuff beds. 



San Pablo 

 Upper Division 



250 ft. 



Bright blue vivianitie sandstones alternating 

 with layers of clay. Estuarine deposits, 

 200 ft. 



Fossil wood zone, coarse, massive cross- 

 bedded sandstones 50 ft. 



San Pablo 

 Lower Division 



350 ft. 



' Coarse, massive, very much cross-bedded 

 sandstones. Eolian (?) deposits, 100 ft. 



Medium to coarse grained fossiliferous sand- 

 stones, thin layers of fine and coarse con- 

 glomerate, tuffaceous cross-bedded sand- 

 stones, coarse gray conglomeratic fossil- 

 iferous sandstones and basal conglomerate, 

 250 ft. 



Monterey 



1600 ft. 



Tuffaceous sandstones, shaly ash beds with 

 leaves and thin layers of cross-bedded 

 sandstones, 400 ft. 



Carbonaceous sandstones alternating with 

 shales and clays, 1000 ft. 



Diatomaceous shale, 200 ft. 



