1913] 



Louderback: The Monterey Series 



205 



San Pablo and General, Merriam, 190 1. — In the same year, 

 J. C. Merriam 45 in "A Note on the Fauna of the Lower Miocene 

 in California" was careful to regard the distinction between 

 lithological types, faunal facies and faunal zones. He said : 

 "One of the most characteristic phases of the Miocene in Cali- 

 fornia is the Monterey shale. The fauna of this formation, as we 

 know it, is limited to foraminifera. radiolaria, fish, cetaceans, a 

 crustacean and a few mollusca. Among the last, Peeten pecli- 

 hami, the indefinite Tellina congesta and a Leda are the most 

 common forms. The fauna belongs to a deep water facies and 

 must not be confused with the faunas of sandy, shallow water 

 deposits. At many places where sandstone is interstratified with 

 the shales, a very sudden change of the fauna is noticed, nearly 

 all of the typical shale species dropping out, but reappearing 

 in shaly layers above" (p. 377). 



Depositional and Faunal Facies. — If we take this statement in 

 connection with the fact that in western Contra Costa County, as 

 had been shown by Lawson in the section quoted above, p. 199. 

 the Monterey series is made up of a succession of sandstones 

 (Vaquero type) and bituminous shales (Monterey type), and 



Mesozoic, possibly Jurassic), the sandstones and shales of Pt. San Pedro 

 (recently shown to be Eocene), the conglomerates and sandstones exposed 

 between Pescadero point and Pigeon point, said to be the best developed 

 part of the series and from which apparently it received its name (classed 

 in the Santa Cruz Folio, 1909, as Chico Upper Cretaceous), and various 

 other sandstones, including those called Vaquero by Arnold and Haehl. 

 From palaeontologieal evidence he considered the series partly Miocene 

 and largely Eocene (?). He was inclined to believe that the "Meta- 

 morphic" rocks of the San Francisco peninsula were part of the series, 

 but separated them as a concession to current geological opinion. He 

 also considered the Monterey (Miocene) and the Merced (Pliocene) as 

 forming a conformable series. 



Such a system which grouped together formations belonging to entirely 

 ditterent, and differently conditioned periods of sedimentation and so 

 widely separated in time and by widespread and important unconform- 

 ities, and which placed the chief division of all the formations from 

 Mesozoic to Quaternary in the midst of a conformable series (the Mon- 

 terey Series) was so evidently out of touch with the facts that it found 

 no adherents and had practically no direct effect on the development of 

 the understanding and nomenclature of the Tertiary formations. It may, 

 however, be looked upon as sowing the seed that led to the use of palaeon- 

 tologieal criteria for dividing the Monterey Series into two formations 

 and that bore its first fruit in the paper above discussed. 



Bull. Dept. Geol. Univ. Calif., vol. 3, no. 16, pp. 377-381, March, 

 1 904. This paper, treated here in the order convenient for logical dis- 

 cussion, was in reality the first paper on the California Miocene to appear 

 in 1904. 



