264 University of California Publications in Geology [Vol. 8 



while the Martinez has a strike of N 70° E, and a dip of 20° to the 

 north. Only the uppermost portion of the Martinez crosses the western 

 limb of the Chieo anticline. Mr. Edward Brainerd obtained very good 

 specimens of Turritella pachecoensis and other characteristic Martinez 

 fossils from these uppermost beds only a few feet from the Martinez- 

 Vaqueros contact. The Vaqueros lies unconformably upon the Mar- 

 tinez in this vicinity. The areal mapping shows the Martinez : Vaqueros 

 unconformity clearly. 



The most complete Martinez section was obtained in the area two 

 and one-half miles north of the Santiago Coal Mine. This section in 

 descending order is as follows : 



Pine-grained tan sandstone, 300 feet. 



Medium-grained concretionary sandstone, 100 feet. 



Thin-bedded fossiliferous sandstone which weathers to a tan color 

 and contains nodules of silicious limestone, 500 feet. 



Coarse gray, arkosic massive sandstone, 200 feet. 



Fine white, thin-bedded sandstone which weathers to a tan and 

 contains limestone nodules which are much more impure than similar 

 ones in the Chico, 200 feet. 



Coarse, light gray, subangular. quartzose, massive sandstone. 100 

 feet. 



Brown micaceous sandstone, 25 feet. 

 Total thickness, 1400 to 1500 feet. 



List of Martinez Species 



223a* 221!) 2218 2217 2216 2220 



Corbula, sp x 



Crassatellites unioides (Stanton) x 



Crassatellites, n. sp x x x 



Cardium cooperi Gabb x 



Dosinia ( ?), sp x 



Glycimeris veatclri var. major (Stanton) x 



Leda, cf. gabbi Conrad x 



Meretrix dalli Diekerson x x 



Meretrix stantoni Diekerson x x 



Modiolus ornatus (Gabb) x 



Meretrix, sp x 



Ostrea, sp. x 



Spisula ( ?) weaveri Packard x 



Tellina undulifera Gabb x 



Tellina kewi Diekerson x x 



Tellina, cf. herndonensis Diekerson x x 



Venericardia planicosta Lamarck x 



* The numbers at top of columns refer to University of California localities. 



