192 University of California Publications in Geology [ VoL - 7 



CONCLUSION 



It results from these relationships that in the region observed 

 the "Vaqueros" is merely a depositional facies, as is also the 

 "Monterey shale," the former type including the lower sand- 

 stone and conglomerate and intercalated shale, according to the 

 usage of Fairbanks and Hamlin, the latter the predominant clay 

 shales, limestone and diatomaceous beds. Eldridge, Arnold, and 

 R. Anderson throw the usually intermediate strata — predomi- 

 nately terrigenous shale and limestone — into the Vaqueros type. 

 In 1he territory mapped by Fairbanks (San Luis Folio) we 

 must hold that Vaqueros sandstone of one portion corresponds 

 to Monterey shale of an adjoining portion, and the same holds 

 in the Santa Clara district mapped by Eldridge and the Santa 

 Maria district mapped by Arnold, Anderson, and Johnson. 



The use of these terms as "formations" representing definite 

 time intervals is misleading and gives a wrong picture of this 

 great depositional series as a whole. The correlations usually 

 put forward are merely formal and not real. Stratigraphically 

 the one thing we can generally recognize definitely is the series, 

 the lower portion of which, from several feet to several thousand 

 feet, is usually terrigenous and is distinguished from underlying 

 beds, either by unconformity, distinctive fauna, or marked change 

 in depositional type. It was brought to a close by an Uncon- 

 formity representing important orogenic movements throughout 

 the whole California coastal region, or at least throughout the 

 whole region in which its deposition had taken place. It repre- 

 sents, in fact, a depositional cycle, and emphasis should be placed 

 on the series as a whole, and a single name shoidd be used to 

 designate it. It represents historically, areally, and economically 

 one of the important periods of deposition in West Coast geologic 

 history, and to be appreciated it should be presented as a major 

 stratigraphic unit — which it is. Its most important relation- 

 ships and essential characteristics are lost when it is presented 

 merely as two or more different "formations." The name 

 "Monterey Series" was proposed some years ago 20 by Lawson, 



20 Univ. of Calif. Bull. Dept. Geol., vol. I, pp. 1-59 (1893). 



