1 68 CALIFORNIA ACADEMY OF SCIENCES [Proc. 30 Ser. 



least suspected by Gabb, as shown in Whitney's' discussion 

 of the region. 



The stratigraphic members of the Eocene, then, are the 

 following : 



Domijean Sands 



Kreyenhagen Shales 



Avenal Sandstone 



The lack of continuity of these members along the entire 

 range is to be attributed partly to their nature and manner of 

 origin, and partly to their degradation previous to the laying 

 down of the succeeding Miocene or Pliocene strata ; naturally, 

 therefore, this lack affects chiefly the lower and upper mem- 

 bers, while the intermediate member is more uniform in its 

 character and at the same time more persistent in its occur- 

 rence. 



The preceding lists of fossils contain representative Eocene 

 species such as indicate that the beds are to be correlated 

 rather with the Tejon than with the Martinez division of the 

 Eocene, and this accords with the fact that the latter horizon 

 has been considered local in its occurrence, or extending 

 only northward from the latitude of Mount Diablo, and also 

 with the fact that the Tejon Beds are found at New Idria and 

 other points only a few miles north of the limits of our own 

 observations. 



Miocene Formations. 



Rocks of the Miocene period do not enter extensively into 

 the stratigraphy of the San Carlos Division of the range 

 north of Alcalde Creek, but south and east of this stream 

 they are more in evidence. Miocene strata occur in some- 

 what disconnected belts running parallel with the Eocene, 

 and to some extent parallel with the Cretaceous. The 

 greatest thickness of Miocene rocks found in any part of the 

 range is near McKittrick and Temblor, although thicker 

 aggregations of strata are found elsewhere, as on the western 

 border of the Carisa Valley. 



1 Geo!. Surv. Calif. Geol. v. i, p. 57. 



