NEOCENE STRATIGRAPHY. 307 



Eocene at Mount Diablo. In Alum Rock Canon, near 

 San Jose, a piece of float rock was found to contain what 

 were thought to be Nummulites, though only cross sec- 

 tions could be obtained. The genus Nummulina, though 

 known to exist from the Carboniferous to the present, is 

 only known to have attained a considerable size and to 

 have been of any geological importance in one age, the 

 Eocene. The evidence of the fucoids near Haakerville 

 is of only minor importance, but must be taken into con- 

 sideration. 



If, as the structure suggests, the conglomerate in the 

 Pescadero section is near the top of the series, it would 

 seem possible that the great thickness of strata below 

 represent not only the deposition of the Miocene, but 

 possibly also of the Eocene. 



In conclusion, it may be stated that below the White 

 Miocene shale or Monterey series of the Miocene, there 

 has been found to lie, unconformably, a series of sand- 

 stones, shales or shaly sandstones and conglomerates, 

 having a thickness of several thousand feet, in part, at 

 least, of older Miocene age, and possibly extending back 

 through the Eocene. 



THE MONTEREY-MERCED PERIOD. 



The Monterey series was among the earliest of forma- 

 tions described in California. It was assigned to the 

 Miocene, and later investigations have not modified that 

 decision. 



The first mention of the Merced series was by Whitney, 

 who merely mentions the finding by Gabb and Remond 

 of Pliocene strata on Seven-Mile Beach.* These beds 

 seem to have commanded little attention until recently. 

 They were recently described more in detail by Professor 



* Geol. Surv. of Cal., Geology, vol. i, p. 79. 



