11 



Coastal Plain to the east, and the Palos Verdes Hills to the 

 south. That part of the Los Angeles Coastal Plain nearest 

 to shore can be further sub-divided into the Santa Monica 

 Plain, Ocean Park Plain, Ballona Creek Gap, and the El Segundo 

 Sand Hills (Poland, et al , , 1945; and McGill, 1954). Because 

 the topography, drainage, structure, and rock composition in 

 the provinces and sub-provinces have played an important role 

 in the submarine geologic history of the adjacent continental 

 shelves and borderland, each area is briefly. described. 



Santa Monica Mountains 



The Santa Monica Mountains vary in elevation from 1,200 

 feet in the east to more than 3,000 feet at their western end. 

 The rocks in the mountains range in age from Mesozoic to 

 Recent and the sedimentary sequences total more than 26,000 

 feet in thickness. Many varieties of rock occur including 

 slate, schist, quartz diorite, basalt and andesite flows, 

 tuffs, breccias, basaltic breccia, rhyolite, trachyte, sand- 

 stones, shales, and conglomerates (Hoots, 1931; Durrell, 1954; 

 and Bailey, 1954). 



The complex structure of the Santa Monica Mountains is 

 shown on geological maps by Durrell (1954) and Bailey (1954). 

 The major faults in the Santa Monica Mountains along the 

 northern part of Santa Monica Bay are shown in Figure 2. The 

 Malibu fault trends east-west along the base of the mountains 

 close to the shore line, and crosses the coast west of Point 

 Dume and Las Flores Canyon, From available data (Bailey, 1954, 

 and Hill, 1954) it is believed that the Santa Monica Mountains 



