Geol.— Vol. II.] ANDERSON— ST RATIGRAPHIC STUDY 1 89 



The exact line of separation between the Cahfornian prov- 

 inces of the later Neocene appears to follow very nearly the 

 line of the outer Coast Ranges as far south as the head 

 waters of the Salinas Valley drainage, and follows in turn 

 the axis of the Santa Cruz and the Santa Lucia ranges, 

 turning eastward to Pine Mountain and the Tehachapi 

 Range at the latitude of Moro Bay. The Pliocene beds of 

 the coastal valleys south of the Santa Lucia Range are 

 faunally more closely related than any of them are with the 

 Pliocene of the interior valleys. The interior basin of the 

 Pliocene includes not only the Great Valley, but the Salinas 

 and Carisa valleys and other small valle3's of the Coast 

 Ranges, probably extending as far north as Lake and 

 Tehama counties. 



Within these provincial limits a faunal and stratigraphic 

 correlation of Pliocene deposits, at least, is likely to be more 

 successful than are present attempts at a detailed correlation 

 of deposits within two or more provincial basins. 



In the Salinas Valley occur late Tertiary beds that can be 

 satisfactorily compared and correlated with those of the 

 Mount Diablo Range. At Santa Margarita and on the 

 Nacimiento River, at La Panza Springs, and on the Estrella 

 and San Lorenzo rivers, are beds that are entirelv similar. 

 At Santa Margarita these beds have been mapped and 

 described by H. W. Fairbanks' as the Santa Margarita For- 

 mation. 



It is quite likely that a correlation of the INIiocene beds, 

 or at least of some of them, will have to be restricted within 

 the same territorial limits. The Vaquero sandstones described 

 by Dr. H. W. Fairbanks as occurring within the drainage of 

 the Salinas River lack thus far any faunal description, and 

 his correlation of these with beds occurring south of the 

 Santa Lucia Range is not supported by any faunal evidence. 

 On the other hand the fauna occurring at the base of the 

 Miocene near San Luis Obispo is characteristic over the 

 whole extent of the coast border, especially south of that 

 point. 



1 San Luis Folio, U. S. Geol. Surv. no. 101. 



