406 University of California Publications in Geology [Vol. 9 



rhyolite and consequent upturning and faulting of Cretaceous and 

 Eocene strata and outpouring of rhyolitic flows and ash deposits 

 (the Sutter formation) upon these faulted and folded sedimentaries ; 

 (6) a period of erosion during which a large portion of the Sutter 

 formation was removed; (7) an intrusion into these older formations 

 mentioned above and outpouring of andesitic materials from a great 

 central volcano; (8) a long erosion interval during which short 

 streams consequent upon the lava slope cut through the andesitic 

 lava into the softer underlying deposits. Of these deposits the soft- 

 est is the Sutter. The pass between the towns of West Butte and 

 Sutter City was cut in this material. The "secondary craters" 

 described in the Marysville Buttes Polio appear to be erosion valleys 

 formed in the Sutter formation by subsequent tributaries of con- 

 sequent streams. 



In conclusion, there does not appear to be any formation in the 

 Marysville Buttes except the Tejon Eocene strata which could pos- 

 sibly be the equivalent of the lone of the Sierran foothills. It has 

 been shown above that these Eocene strata are the off-shore 

 equivalents of the inshore lone. 



SUMMAEY OF FAUNA OF THE SIPHONALIA SUTTEKENSIS ZONE 



The discovery of several new areas in which the Siphonalia sut- 

 terensis zone was represented and large additions to the faunas 

 modify the previous conclusions of the writer concerning this zone. 

 Many of the forms which were thought to be characteristic have 

 been found at lower horizons and several more species characteristic 

 of the middle and lower portions of the Tejon group are now re- 

 ported from this zone. The list of species obtained from this zone 

 is given below. 



List of Species From Localities in the Siphonalia Sutterensis Zoxe 



1853 1856 692 2225 2365 



Nodosaria, sp x 



Balanophyllia variabilis Nomland x x 



Coral, sp. a x 



Flabellum, sp x 



Stephanophyllia californica Nomland x 



Trochocyathus (?) perrini Dickerson x 



Schizaster lecontei Merriam x 



Acila gabbiana, n. sp x — - x x 



Area hornii Gabb x x 



Avicula pellucida Gabb x 



