Vol. IV] ANDERSON AND MARTIN— NEOCENE RECORD 47 



uplifts taking place at the close of Monterey time and continu- 

 ing during the early part of Santa Margarita (San Pablo) 

 time, followed by subsidence, resulted in the absence of the 

 lower beds in the areas that were elevated. In the San Juan 

 district where deposition was continuous the whole series is 

 present, while along the eastern slope of the Santa Lucia Range 

 only the middle and upper portion is represented. The charac- 

 ter of the sediments and the comparatively small thickness of 

 the beds at Santa Margarita agree in support of this explana- 

 tion. In the region of Mount Diablo and Pinole, if the San 

 Pablo is conformable upon the underlying beds, as it appears 

 to be, we have the same condition that is here described, and 

 the Santa Margarita of the San Juan district could be the 

 equivalent of the San Pablo. The following species were ob- 

 tained from the Santa Margarita of the San Juan district, and 

 warrant the approximate correlation of these beds with both : — 



Astrodapsis antiselli Conrad 

 Astrodapsis tmnidus Remond 

 Astrodapsis zvhitneyi Remond 

 Chione, sp., a 

 Chione, sp., h 

 Macoma nasuta Conrad 

 Ostrea panzana Conrad 

 Ostrea titan Conrad 

 Phacoides, sp. 

 Pecten crassicardo Conrad 

 Pecten estrellanus Conrad 

 Pecten sancti-ludovici, n. sp. 

 Trophon carisaensis Anderson 

 Turritella carrisaensis , n. sp. 

 Tamiosonia gregaria Conrad 



Etchegoin Group. — The occurrence of the Etchegoin group 

 within the limits of the San Juan district has not been recog- 

 nized, neither has it been disproved. A few miles to 

 the east of the San Juan ranch house there are thick beds of 

 clays, sands and gravels dipping to the westward that may in 

 part belong to this group. In their physical appearance they 

 are not unlike beds of Etchegoin age in the region of the 

 Kettleman Hills. These beds of possible Etchegoin age are 



December 30, 1914. 



