1914] 



Dickerson: Martinez of Bock Creek 



295 



THE FAUNA OF THE MARTINEZ 



Only the lower four hundred feet of the Martinez Group were 

 markedly fossiliferous and most of the collections were obtained from 

 these strata. 



List of Species Obtained from Rock Creek Martinez 



Cidaris, sp 



Terebratula, sp 



Crassatellites, ef. unioides Stanton 



Crassatellites, sp 



Cardium cooperi Gabb 



Cucullaea, cf. mathewsonii Gabb 



Glycimeris veatehi, var. major Stanton. 



Meretrix, sp 



Ostrea, sp 



Phacoides muirensis Dickerson 



Saxidomus noblei, n. sp 



Teredo, sp 



Dentalium cooperi Gabb 



Amauropsis martinezensis Dickerson ... 



Brachysphingus liratus Gabb 



Calliostoma, sp 



Natica pinyonensis, n. sp 



Lunatia hornii Gabb 



Molopophorus( ?) howardi, n. sp 



Turitella, sp 



Turritella pachecoensis Stanton 



Turritella martinezensis Gabb 



Loc. 



2245 



Loc. 

 2246 



Loc. 

 2247 



Loc. 

 2248 



Loc. 

 2249 



This fauna contains such characteristic Martinez species as Tur- 

 ritella pachecoensis, Turritella martinezensis, Brachysphingus liratus, 

 Amauropsis martinezensis, Glycimeris veatehi var. major. All of 

 these forms are restricted to the lower and middle portions of the 

 Martinez Group of northern California. 



MIOCENE (?) STRATA 



A formation consisting of fanglomerates, conglomerates and sand- 

 stone is exposed in the area known as the Devil's Punch-bowl in the 

 Rock Creek Quadrangle. Its superficial extent is approximately four 

 square miles, but it underlies most of the bolson area which is covered 

 by the Pleistocene fanglomerates on the west. The base of this forma- 

 tion is exposed along a small creek a mile southwest of Shoemaker. 



