20 



composed entirely of eolian sands lying directly on the Palos 

 Verdes sand in most of the area, and that the sand dunes were 

 formed continuously as the sea regressed across the Palos Verdes 

 surface o 



Zielbauer and Davis (undated) note that the Palos Verdes 

 formation in the Hermosa-Manhattan Beach region is composed 

 mainly of sands and gravels which are similar to the overlying 

 coastal deposits, except that they occur somewhat farther inland 

 and include calcitic fragments. The formation is absent in 

 some of the region and its absence is attributed to marine and/ 

 or fluvial activity.. There is more or less continuous horizon 

 of relatively impervious deposits composed of silts, silty sand 

 stringers, sandy clays, and clays that lie directly below the 

 sand dune and coastal deposits „ This layer, called the "clay 

 cap", is unusually flat, varying from 10 feet above sea level 

 to about 10 feet below sea level, and reflects the underlying 

 structure which consists of transverse drainage channels. 

 The clay cap feathers out completely at the present strand 

 line, and it is absent in a well 800 feet inland. 



The drainage of the El Segundo Sand Hills (Fig, 3) shows 

 that only a narrow belt of that shoreline adjacent to Santa 

 Monica Bay drains into the bay. 



Palos Verdes Hills 



The Palos Verdes Hills, which form the southern and south- 

 eastern boundary of Santa Monica Bay, are a conspicuous uplift 

 along the southern border of the Los Angeles Basin. For the 

 most part, the hills have a relatively simple structure con- 

 sisting of broad gentle folds which from an anticlinal structure. 



