Vol. 4] Weaver. — Palaeontology of the Martinez Group. 113 



The genera represented in both resembled most closely the fauna 

 of the Eanikot group. This group is supposed to belong to the 

 lower Eocene. The small number of common forms indicates 

 that there was probably no direct faunal connection between 

 India and the Western Coast of North America in Martinez 

 times. The same view is arrived at by Professor J. P. Smith*, in 

 which he states "in the upper Chico horizon of California and 

 Oregon the connection with India appears to cease," and "dur- 

 ing the early Tertiary or Tejon epoch in California we have no 

 evidence of any migration from Asia." The evidence seems 

 also to point to the fact that during this period the Martinez seas 

 were isolated from the regions of the southeastern United States. 

 Later, during the Tejon, a passage was possibly opened. 



Although these localities are widely separated, and only a 

 small proportion of the genera is common, yet there seem to be 

 sufficient distinctive forms not only to place the Martinez Group 

 in the Eocene, but also to show that it represents a portion or all 

 of the lower quarter of the Eocene. 



SUMMARY. 



From the foregoing discussion it is evident that the Martinez 

 represents a distinct division of time in the geological history of 

 Calfornia. It contains a fauna distinct from both the Chico 

 and the Tejon. On the average it is composed of about two thou- 

 sand feet of thick-bedded sandstones, together with some shales, 

 thin-bedded sandstones and conglomerates. Its geographical 

 extent as at present known is confined to southern Lake County 

 and a belt extending north and south across the Strait of Kar- 

 quines. Its position in the geological scale seems to correspond 

 most closely to a portion or all of the lower quarter of the Eocene. 



^Periodic Migrations between the Asiatic and the American Coasts of the 

 Pacific Ocean, by J. P. Smith. Am. Jour. Sci., Vol. XVII, p. 224, 1904. 



