1916] 



Dickerson: Tejon Eocene of California 



479 



Isocardia, Martesia, Cadulus, Caricella, Valuta, Volutilithes, Lyria, 

 Mitra, Exilia, Pseudoliva (f), and Scala (Epitonium) are Midway 

 genera which are represented in the Tejon but not present in the 

 Martinez. Most of these important genera are represented in the 

 Recent fauna of the tropics and hence the stage of evolution of the 

 Midway fauna is apparently nearer to the Recent than the Martinez 

 and, on the whole, is more closely related to the Tejon. 



Proposed Correlation 



Identical species, similar stages of generic evolution and the 

 mutations of Venericardia planicosta, all show a much stronger 

 relationship of the Tejon group to the three lower formations of the 

 Gulf Province, the Midway, Wilcox, and Claiborne, than was sus- 

 pected. Tejon time was long and was probably equivalent to 

 Midway (in part, at least), Wilcox, and Claiborne eons. The Jack- 

 son may be represented by the upper portion of the rhyolitie tuffs, 

 the clay rock of Turner. 



This study confirms and modifies somewhat the writer's conclu- 

 sion "that the Martinez is not only equivalent to a portion of the 

 Midway, but represents a still earlier stage of the Eocene as well". 

 The generic relations between the Tejon and Midway are so close 

 that it seems probable that they are correlative at least in part. 

 Possibly the Martinez is the marine eqttivalent of the Puerco and 

 Torrejon of New Mexico, that is, Paleoeene. 



Pacific Province Gulf Province 



Siphonalia sutterensis zone 1 ., 



„ , , „. . .... . ), Claiborne 



Balanophyllia variabilis zone f 



< D . „„ . . (Lower Claiborne 



Rimella simplex zone ) 



" " ^Wilcox 



Turbinolia zone Midway 



Tejon 



fSolen stantoni zone 

 zJ Trochocyathus zitte 

 [Meretrix dalli zone 



MartinezJ Trochocyathus zitteli zone], Puerco and Torrejon(?) 



GENERAL CONCLUSIONS 



(1) The Tejon group is both a stratigraphic and fauna] unit 

 which is very distinct from the groups above and below. 



(2) The Tejon group is unconformable upon the Martinez 

 Eocene and Chico-Cretaceous in the vicinity of Mount Diablo. 

 Unconformities are inferred in other areas as well. 



