1914] Dickerson: Fauna of the Martinez Eocene of California 89 



(Surculites) inconspicua Gabb, Ostrea weaveri, n. sp., Tellina kewi, 

 n. sp. This fauna was found in gray-green glauconitic sandstone 

 typical of the Trochocyathus zitteli zone. Although Chico jossils have 

 been found only a short distance away, no basal Martinez beds appear. 

 Evidently they were covered by the overthrust of the Chico upon them. 

 The Martinez sandstone containing fossils at Selby Smelter is one or 

 two hundred feet thick. Above this lie four or five hundred feet of 

 gray-green foraminiferal shale with a little interbedded sandstone. 

 This shale is in turn overlain unconformably by the Monterey. 

 Whether this shale at the contact is Tejon or Martinez is difficult to 

 determine, as it has thus far yielded only poorly preserved foramini- 

 fers. Good exposures are not common in this vicinity and the struc- 

 ture is complicated. One-quarter of a mile south of Selby, and about 

 two hundred feet from the Eocene-Monterey contact, the writer found 

 Urosyca caudata and one or two other Martinez species in sandstone 

 exposed in a road cut. This leaves but two hundred feet of strata 

 which could be assigned to the Tejon at this place. Since no Tejon 

 has been found along the Monterey contact for several miles to the 

 south, it appears that the shales underlying the Monterey are probably 

 Martinez. 



MARTINEZ AT LOWER LAKE, LAKE COUNTY 



TRANSITIONARY BEDS OF GABB 



Gabb 22 referred to the Transitionary Beds of Lower Lake as fur- 

 nishing some of the most important evidence indicating the continuity 

 between his "Cretaceous A" and "Cretaceous B." That author 

 stated that he found at a " locality near Clear Lake . . . within a space 

 of two feet .... an admixture of upper and lower forms proving the 

 existence of a transitionary bed or group of beds. ' ' 



Although geologists of the present day do not accept his view we 

 shall see in the discussion which follows that Gabb appreciated the 

 peculiarities of the fauna found here. His keen vision is particularly 

 worthy of note when we remember that he had no libraries or collec- 

 tions containing comparative material to consult. A virgin field was 

 his, with all the difficulties that usually confront the pioneer in science. 



22 Gabb., W. M., Proc. Cal. Acad. Nat. Sci., vol. 3, p. 302, 1866. 



