216 University of California Publications in Geology [Vol- ^ 



way. The vertical movement involved was not great, and such 

 a movement might have extended over the deeper portions of 

 the area of deposition in Monterey time without effecting a suffi- 

 cient change in the depth of the water to alter the character of 

 the sediments" (p. 10). 



I have pointed out above that similar, oscillations did take 

 place in the Santa Clara Valley region, Los Angeles district and 

 Puente Hills. 



Santa Cruz Folio, Branner, Newsom, and Arnold, 1909. — 

 Considerable areas of rocks representing the Monterey series 

 have been mapped by Branner, Newsom, and Arnold in the Santa 

 Cruz quadrangle, the folio 03 for which appeared in 1909. They 

 are presented as two formations separated by an unconformity, 

 and presumably representing different time intervals in the 

 geologic scale. 



"The Vaqueros sandstone, of lower Miocene age, is one of 

 the most important formations of the quadrangle. . . . The sand- 

 stone varies in texture from fine grained beds to conglomerate, 

 but is usually medium grained. C4enerally it is brown or buff 

 in color. . . . The Vaqueros in general lies conformably above 

 the San Lorenzo formation, and there is often a gradual change 

 from one formation to the other. . . . Southwest of Ben Lomond 

 Ridge, Big Basin, and Butano Ridge the thin sandstone at the 

 base of the supposed Monterey shale, tentatively included with 

 the Vaqueros, overlaps unconformably the San Lorenzo, the 

 Butano and the pre-Cretaceous diorite" (p. -4). 



' ' The relation of the Vaqueros sandstone to the overlying 

 beds is not so clear" (?) "as are its relations to the underlying 

 strata. Around the northwest end of Butano Ridge the diato- 

 maeeous shale (supposed Monterey) rests directly on the Bu- 

 tano. and the thin sandstone (regarded as possibly Vaqueros) 

 is absent. Elsewhere in the quadrangle there is commonly a 

 marked difference in the dips of the Monterey strata and those 

 of the Vaqueros sandstone, and an unconformity is therefore 

 believed to exist generally between the two formations. Inas- 

 much, however, as the line of contact nearly always occurs in 

 densely wooded or chaparral-covered regions and where the rocks 



63 U. S. Geol. Surv., Santa Cruz Folio, California, no. 163 (1909). 



