21 



There are few major faults, but those that do occur roughly 

 parallel the axis of the hills. The most important fault is 

 not exposed at the surface, but is a major structual feature 

 in the schist basement and the immediately overlying rocks. 

 This fault has been called the "San Pedro Fault" by subsurface 

 geologists, but Woodford, et^ al. (1954) have termed it the 

 "Palos Verdes Fault Zone". According to Woodring et^ al_. (1946) 

 the Palos Verdes Hills were uplifted with the San Pedro fault 

 (or the Palos Verdes fault zone) spearating the hills from the 

 Los Angeles Basin. This structural feature conceivably extends 

 far out into Santa Monica Bay (Fig. 4). 



The exact age of the major faulting along the northern 

 border of Palos Verdes Hills is still unknown, but the zone is 

 probably still active. The strongest deformation in the 

 Palos Verdes Hills took place during the Upper Pliocene. Less 

 marked deformation during the Middle Pleistocene, and still 

 weaker movements occurred near the close of the Pleistocene 

 period. Deformation has been so recent along the northern 

 border of Palos Verdes Hills that the lower marine terrace 

 and its associated deposits have been slightly to moderately 

 deformed. 



The basement rock is glaucophane schist and altered basic 

 igneous rocks of probable Jurassic age. Unconf ormably above 

 the basement rocks are several thousand feet of strata of 

 Miocene and Pliocene age and a relatively thin veneer of 

 terrace deposits of Pleistocene age. The rocks of Miocene 

 age are cherty, phosphatic, and silty shales, mudstones, 

 basaltic sills and tuffaceous beds. Pliocene rocks include 



