172 



CALIFORNIA ACADEMY OF SCIENCES [Proc. 30 Ser. 



Kreyenhagen Wells. 



Astrodapsis nierrianii n. sp. 

 Pecten discus Conrad 

 Pecten estrellanus Conrad 

 Turritella ocoyana Conrad 

 Agasoma graviduni Gabb 

 Neverita callosa Gabb 

 Mactra densata Conrad 

 Venus {Chione) tanblorensis n. sp. 

 (rel. C. guidia.) 



Zirphaea sp. 



Natica sp. 



Mactra {Spisula) sp. 



Ostrea sp. 



Hemifiisus wilkesana n. sp. 



Lticina acutilmeaia Conrad 



Area moiitereyana Osmont 



Balla?ius sp. 



Sulphur Springs, Zapata Chino Creek. 



Mactra densata Conrad 

 Mactra sp. 



Area montereyana Osmont 

 Tapes sp. 



Lucina sp. 



Venus ( Chione) temblorensisn. sp. 



Astrodapsis merriami n. sp. 



The species given in the preceding lists are characteristic 

 of the Lower. Miocene as it occurs in the Great Valley of 

 California, and perhaps that of all the interior valleys of the 

 State. 



The more northerl}^ belt of Miocene rocks in the Coalinga 

 district begins a few miles to the northwest of Coalinga, on 

 the north side of Sec. 2, T. 20 S., R. 14 E., and extends in 

 a broad curve northeasterly, northerly, and northwesterly for 

 many miles, or quite beyond the Cantua Creek. 



It is fairly well shown on the Coalinga geologic map pre- 

 pared for this paper (PL xxxv). The dip of the strata is 

 always toward the Great Valley at angles varying from 20° 

 to 35°, and in directions normal to the strike. In a few cases 

 only, and notably in one or two cases, is the structure com- 

 plicated. In the main the structure of all the Tertiar}^ rocks 

 is monoclinal. But on the S. E. % of Sec. 20, T. 19 S., 

 R. 15 E,, the Miocene rocks are exceedingly crushed and 

 distorted by compression, and to some extent this distortion 

 extends also to the Eocene and the Pliocene rocks. 



Two members of the Miocene have been detected in the 

 Coalinga district proper, but possibly others occur a few 

 miles to the northwest. For the most part the Temblor Beds 

 are not present, and the following members only are in 



