218 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



to the above section and of about the same thickness. It is as 



follows : 



Conglomerate and coarse sand beneath soft Tulare strata. 



Oil sands, 



Clay and marly shale. 



Oil sand and conglomerate. 



Hard cemented coarse gray sand with fragmental shells. 



Granite pebbles and coarse sand. 



Light shaly oil stained beds. 



Gray sand. 



Beneath the gray sand is a great thickness of organic 

 shales. 



STRATIGRAPHY 



Like the Tulare, the Etchegoin forms both flanks of an 

 eroded anticline in the South-End McKittrick area, and is in 

 general more steeply inclined than the Tulare with some small 

 variances in strike. Along the south flank it is partly covered 

 by wash from the overlapping Tulare and on the north flank 

 is locally faulted. A good example of this faulting, which is 

 very complex, is found near the south line of Sec. 27 and in 

 the northern part of Sec. 34. This faulting is i)robably the 

 southward continuation of the faulted zone which in the Mc- 

 Kittrick field has thrown a part of the shale series (Santa 

 Margarita or Monterey) across the top of the oil bearing zone, 

 from which, in one well at least. Etchegoin fossils have been 

 found. 



RELATION TO PETROLEUM 



Directly overlying the great masses of organic shales the 

 sands of the Etchegoin have acted as storage reservoirs for 

 the oil. As is shown in the sections, the oil sands lie scattered 

 throughout the whole of the exposed Etchegoin, being closely 

 associated with fossils of that age. This condition is true of 

 most of the West Side fields as will be mentioned later. In 

 the South-End McKittrick area the surface exposures show- 

 ing the relation of the oil to the Etchegoin are good, but un- 

 fortunatey little drilling has been done in that immediate 

 neighborhood. A few wells, principally in Sec. 34, formerly 

 known as the Belgian wells, have produced some oil. Nearly 

 everywhere in this district that Etchegoin strata are exposed, 

 oil sand or oil seepages are found associated with them. The 



