1913] 



Louderback: 



The Monterey Series 



239 



Smith has recently published most convenient lists of the inverte- 

 brate fauna of the Monterey series in his "Geologic Range of 

 Miocene Invertebrate Fossils of California" under the desig- 

 nation of "lower Miocene" faunas." 3 The reader interested in 

 the palaeontologic data is referred to this useful paper, and no 

 attempt will be made to present a faunal list here. 



As for the offshore (shale) fauna, it is meager and appar- 

 ently not so characteristic, and references of shale — especially 

 siliceous shale — facies to the Monterey series have to be made 

 with care, and either with regard to their association with char- 

 acteristically fossiliferous sandstone, or to their inclusion within 

 the limits of the sedimentary series of rather characteristic habit, 

 between the unconformities already described. 



Faunal Stages. — There appear to be at least two 94 widely 

 recognizable faunal stages in the Monterey littoral faunas, the 

 older of which is found only along the more immediate coast 

 region of the present time. If we accept these as representing 

 real stages and not merely distributional facies, they strengthen 

 materially the idea suggested by stratigraphic considerations and 

 geographic distribution of depositional types, that the invasion 

 of the Monterey sea was a gradual process, that during the earlier 

 part of the period (zone of Turritella hoffmanni or inezana) 

 deposition was confined to the present coastal region, and that 

 only during a later stage did it stretch over across the present 

 coast range country and cover part of what is now the San 

 Joaquin valley and Sierra Nevada foothills. And while coarse 

 terrigenous deposits were gathering along the Cantua-Coalinga- 

 Kern River-San Emigdio border region (the Temblor beds of 

 F. M. Anderson, Vaqueros formation of Arnold, Robert Ander- 

 son, Johnson, etc.), very pure diatomaeeous shales were forming 

 over most of the coastal Monterey-San Luis-Santa Barbara 

 region, and even over some of the interior — the McKittrick- 

 Temblor region — (Monterey shale or Monterey formation of 

 various authors). 



osProc. Cal. Acad. Sci., 4th Ser., vol. 3. pp. 161-182 (1912). 



•4 Merriam recognizes an upper zone in the Contra Costa County region 

 (see page 206 of this paper), but it is not discussed here, as it is either 

 absent or at least has not yet been definitely recognized in the other 

 Monterey areas. 



