1913] 



LouderbacTc: The Monterey Series 



191 



Relationships op Different Sections of the Series 



The foregoing table is a comparison of the general features 

 of several sections of the Monterey- Vaqueros series, the division 

 lines being drawn on a lithological basis — the only basis on 

 which actual divisional lines have been drawn in the areas repre- 

 sented. But a careful comparison of different sections of the 

 Santa Clara Valley region gives very suggestive evidence, as 

 explained above, that much of the terrigenous shale in the Sespe 

 district corresponds to diatomaceous shale south of the Santa 

 Clara Valley, and that much of the Modelo sandstones corre- 

 sponds to contemporaneous deposition of siliceous shales south 

 of the valley. 



A study of numerous sections along the coast to the north of 

 Point Conception has led the writer to similar conclusions for 

 other areas. In the Santa Maria district conglomerate at one 

 point is seen to take the place of sandstone within a few miles 

 (as in the region between Suey Creek and Huasna Creek) ; 

 sandstone at one point is replaced by terrigenous shales within 

 a moderate distance (as in the Casmalia Hills). The rapid fluc- 

 tuation in thickness of the terrigenous basal members of the 

 conformable series which grade into biogenic calcareous and 

 then siliceous shales, the terrigenous members retaining the same 

 faunal facies, indicates that the terrigenous material at one local- 

 ity is strictly contemporaneous with detrital material of a dif- 

 ferent grain and with biogenic material at others. This rela- 

 tionship is suggested practically everywhere that the series is 

 developed. 



In particular, it is frequently observable that the terrigenous 

 material is definitely related to older land masses in many local- 

 ities, and that the biogenic shale increases in amount in definite 

 directions — often in directions that point to greater distance 

 from an old shore line, as was brought out for the Santa Clara 

 region and will be indicated for several other localities in a later 

 part of this paper. 



