1913] 



Louderback: The Monterey Series 



201 



A few of the workers used the term Miocene instead of 

 Monterey, although all believed that it represented the same 

 series and displayed everywhere the same peculiar lithologic 

 types which up to that time were considered characteristic of 

 the Monterey period of deposition in the California coastal 

 province. 



Advantage of Loeal (Provincial) Name. — Even at that time 

 it was evident that the term Monterey was preferable to Miocene, 

 because the former designated definitely a series of deposits, 

 representing a depositional period in a certain province of sedi- 

 mentation, while the latter represents a time interval referred 

 to a far distant standard and not necessarily coextensive in time 

 with the period of deposition here under consideration. Its 

 determination as Miocene is dependent upon the estimated rela- 

 tion and meaning of faunal characteristics, the interpretation 

 of which has varied up to the present and will probably continue 

 to vary. Furthermore, J. C. Merriam had already in 1898 de- 

 scribed the San Pablo formation, 4 " which in Contra Costa County 

 and, as since determined, at many other localities, overlies the 

 Monterey. This series, originally referred by Merriam to the 

 "middle Neocene," has been considered by some to be Plio- 

 cene, and by others upper Miocene — this latter view being prob- 

 ably the prevailing one among palaeontologists at the present 

 time. Throughout the Coast region, wherever it comes in contact 

 with the Monterey, it is believed to rest upon the latter uncon- 

 formably, and over considerable areas the unconformity is very 

 marked and represents a considerable amount of orogenic dis- 

 turbance. If we accept the Miocene age of the San Pablo, there- 

 fore, the Monterey, the period of orogenic disturbance, and the 

 San Pablo would all be included under the designation Miocene. 



PERIOD OF 1904 TO THE PRESENT (1912) 

 Opening of the Period. — The year 1904 was very prolific of 

 publication on the California Miocene and marked the beginning 

 of the dismemberment of the Monterey series and the multi- 

 plication of formational names, both within the limits of this 

 series and throughout all the Tertiary terranes, so that after a 



-t" Bull. Dept. Geol. Univ. Calif., vol. 2. no. 4, May, 1898. 



