Crandall — Santa Clara Valley Region in California. 53 



In northern California, the Horsetown overlaps the Knox- 

 ville and the Chico overlaps the Horsetown, but in the vicinity 

 of Mt. Diablo the Horsetown cannot be considered to overlap 

 the Knoxville. At the time of the movement or some time 

 during the Horsetown epoch, the large intrusions of serpen- 

 tine through the Coast Ranges must have taken place, as they 

 are found in numerous localities intruded into the Knoxville, 

 but not into the Chico beds.* 



At the end of the Horsetown period there was a gradual sub- 

 mergence of the whole coast, which allowed the transgression 

 of the Chico to the foot of the Sierras, in northern California, 

 and permitted the Chico sea to cover the present Sacramento Val- 

 ley. In southern California, the Chico shore line, as given by 

 the authorities previously quoted, is close to the present shore 

 line, indicating a fairly uniform subsidence of the coast, but 

 with the southern end of California relatively higher than the 

 northern, as were the conditions during Horsetown time. In 

 northern California, the Chico has transgressed nearly to the 

 JSTevacla State line, but in southern California the shore line, 

 from the present evidence, could only have been about as far 

 east as the base of the present San Jacinto range. 



Resume and conclusions. — In the Santa Clara Yalley region 

 there are scattered localities where the Cretaceous is present. 



The three horizons of the Cretaceous are represented among 

 these various localities. 



The Knoxville is present at fourteen, the Horsetown at five 

 and Chico at five. At three of the five localities where Horse- 

 town is present Chico is present also. 



The Knoxville and Chico are both on the east and west 

 sides of the Santa Clara Yalley. The Horsetown is found only 

 upon the east side in the vicinity of Mt. Diablo. 



The Knoxville and Chico extend farther south than the most 

 southerly of the localities considered in this paper. The Horse- 

 town is not known in any place farther south than the Arroyo 

 del Valle. 



The Cretaceous is represented at Mt. Diablo and Arroyo del 

 Yalle by about one-half the thickness of the maximum section on 

 Elder Creek. 



There is no unconformity between Horsetown and Knoxville 

 or Horsetown and Chico in this immediate region. 



There is nothing to show interrupted sedimentation at the 

 last mentioned localities. 



The continuity deposition of the Cretaceous series in northern 

 California, as advocated by Diller and Stanton, is accepted. 

 Continuity of deposition is considered true of the series at Mt. 

 Diablo and Arroyo del Valle. 



* F. M. Anderson, Cretaceous Deposits of the Pacific Coast, Proc. Cal. Acad. 

 Sci., 3d series, ii, 1, p. 54. 



