1913] Dickerson: Fauna of Eocene at Marysville Buttes 263 



Resting- upon the Eocene are 500-600 feet of lone gravels and 

 sands. The two uppermost Eocene members, which are very 

 fossiliferous, can be easily recognized in the field by the bright 

 red, clay soil formed through their decay. The limestone con- 

 cretions, which are sometimes yellow, contain many small, dark 

 green to black, rounded grains. When these are carefully ex- 

 amined with a hand lens they are found to be foraminiferal casts 

 composed of glauconite. The green shales as well as the sand- 

 stone also contain glauconite and foraminifers. The strata are 

 lithologically similar to certain horizons in the Martinez, but the 

 character of the fauna here compels us to abandon the notion that 

 green glauconitic sandstone and shale are absolutely indicative 

 of the Martinez in the middle California region. Glauconitic 

 sandstone also occurs in the Tejon of the Mt. Diablo region. 



On the east side of South Butte the writer has mapped an- 

 other Eocene area which has about the same sequence as the 

 above. Thin strata of coal are reported by Watts" and later by 

 Lindgren 7 and Turner, from the lower portion of this section. 



According to H. Hannibal some of the area south of South 

 Butte mapped as lone is Cretaceous. 



List of the Fauna prom the Uppermost Eocene of 

 Marysville Buttes 



The writer found most of the following species at the locality 

 to which reference was made by Watts, and by Lindgren and 

 Turner. The species starred (*) were reported by Cooper, but 

 were not found by the writer. The single species marked by a 

 dagger (f) was found at a locality two miles east of South Butte. 

 The occurrence of each species is marked by an "x" in the 

 columns representing separate localities. 



o Watts, W. L., The Gas and Petroleum Yielding Formations of the 

 Central Valley of California. Bull. No. 3, California State Mining Bureau, 

 p. 9, Aug., 1894. 



7 Lindgren, W. and Turner, H. W., Marysville Folio, U. S. Geol. Surv. 

 Folio 17, p. 2, April, 1895. 



