1904. 



HAEHL AND ARNOLD — THE MIOCENE DIABASE. 



19 



Miocene. — (^i) The Vaquero Sand- 

 stone. The lower Miocene of the 

 area consists of a series two or 

 three thousand feet thick of mas- 

 sive, coarse, yellowish sandstone 

 layers, interbedded with a few layers 

 of varying thickness of dark-colored 

 argillaceous shale, the whole overlain 

 by three or four hundred feet of thin- 

 bedded siliceous shales. The lower 

 part of this series of beds, including 

 most of the sandstone, appears to 

 have the same fauna and occupy the 

 same stratigraphic position as the 

 Vaquero sandstone of the Salinas 

 Valley.^ The name ''Vaquero" will, 

 therefore, be used to designate the 

 lower Miocene sandstone in the area 

 under discussion. The sandstone and 

 shale series is typically developed in 

 the region between the headwaters of 

 Stevens Creek and the lower portion 

 of Peters Creek. Fig. i shows a typi- 

 cal section of this area. 



The fauna of the Vaquero sandstone 

 series indicates its lower Miocene 

 age. The following fossils, most of 

 which are characteristic of the lower 

 Miocene, are among others found in 

 the Vaquero sandstone on Mindego 

 Creek, Langley Creek, at the head of 

 Stevens Creek, and at other points in 

 the area under discussion : 



5f D.r/, G 



^ The name for this sandstone was suggested by Mr. Homer Hamlin, and was 

 first used by Dr. Fairbanks in the San Luis folio. This sandstone is typically 

 developed in the Los Va(|ueros Valley, near the Salinas Valley, Monterey 

 County. 



