428 University of California Publications in Geology [Vol. 9 



fauna is tentatively placed as the equivalent of this zone. The writer 

 is inclined to regard it as slightly higher than the typical locality ot 

 the Turbinolia zone owing to the large percentage of species which 

 are present in the type Tejon. 



FAUNA OF WHITE SANDSTONE MEMBER 



Just below the white shales of Eocene-Oligocene age there is a 

 richly fossiliferous sandstone stratum. This stratum is ordinarily 

 firmly cemented, but at one small cropping, surface waters had in 

 some way removed the cement and left the shells in a perfect state of 

 preservation. Sixty-seven species were obtained from this locality 

 alone. They are listed below under Univ. of Cal. locality 672. This 

 fauna is evidently related to the fauna of the type Tejon, although 

 it contains about fifteen new species. The large number of new spe- 

 cies would be very puzzling if it were not for the presence of Turri- 

 tella uvasana and other species typical of the Tejon group. Turritella 

 uvasana is a good guide fossil for the middle portion of the Tejon 

 group, but it is not known to occur in the Siphonalia sutterensis zone 

 of California, and, if present in the Turbinolia zone, is rare. 



A faunal list for the vicinity between Cantua and Domengine 

 creeks is given on pages 430-434. 



The fauna found at locality 672 when compared with that of the 

 lowermost strata in this region (locality 1817) illustrates the marvel- 

 ous unity of the entire Tejon fauna. The number of species in common 

 is quite remarkable when one remembers that stratigraphic distance 

 between them is at least 2000 feet. Does this unity mean that only a 

 short geologic time is represented by the intervening strata? The 

 writer does not regard shortness of time as a plausible explanation, 

 but is inclined to believe that uniformity in climatic conditions in 

 upper Eocene time retarded the development of new forms. 



Several workers in tins field report the existence of a well marked 

 unconformity in the middle of the section. The time represented by 

 this unconformity is difficult to evaluate. The only method at present 

 available is the faunal one, and as has been previously shown the 

 faunas from above and below the unconformity are as a whole quite 

 similar. There is no well marked difference in dip and strike reported 

 along the unconformable contact, but the evidence consists of a sharp 

 change in lithology and the penetration of the underlying strata by 

 crustacean bore-holes which are filled with sand of the overlying 



