94 



GUIDEBOOK OF THE WESTERN U:NITED STATES. 



vatcd a valley about a mile wide and 100 feet deep in the marine deposit 

 and filled the trench with river deposits, the second Quaternary for- 

 mation. This in turn is covered by the alluvium of the present plain. 



Geologic formations in the oilfields of the coastal region of southern California, 



Era. 



"o 



N 

 O 



o 



O 



o 



63 



-a 



System or 

 period. 



Quater- 

 nary. 



Tertiary. 



Creta- 



ceous 



Series or 

 epoch. 



Recent 



Group or forniation. 



Pleisto- 

 cene. 



Pliocene. 



Alluvium, terrace deposits. 



Approxi- 

 mate 

 thickness, 

 in feet. 





1,000 



Pa.so Robles 

 formation. 



Fernando 

 formation. 



Pismo and Santa 

 Margarita for- 

 mations. 



1, 000 



Pliocene. 



Oligo- 

 cene. 



-LTnconformity 



Monterey group, including 

 Vaqueros sandstone. 



7,000 

 2,000 



10,000 



Sespe formation. 



Eocene. 



Upper 



Creta- 

 ceous . 



Tejon formation. 



Martinez 

 mation . 



for- 



Topatopa 

 forma- 

 tion. 



4,300 



5,000 



-Unconformity. 



4,000 



Chico formation 



-Unconformity 



4,000 



Jurassic? 



Lower 



Cretaceous 

 or Shasta. 



Knoxville formation. 



-Unconformity 



Franciscan group 



-Unconformity 



ScMst and limestone in 

 truded by granite. 



Quantity of oil aiid 

 quality (Baume). 



Large 

 oil; 



Also 

 turn. 



11^-19°. 

 awphal- 



Oil; 12^-35 



Good oil; 26''- 

 30°. Also 

 some heavier 

 oil. 



Some high-grade 

 oil; lower oil 

 horizon. 



