100 



direction over most of the bay. Except for the uppermost few 

 inches, or feet in a few logs, most cores do not show good 

 core-to-core correlation. It is obvious that great variations 

 in sedimentation have taken place over most of the bay. Some 

 of the factors effecting the sedimentation in Santa Monica Bay 

 and the significance of these cheinges in deposition will be 

 discussed after considering the geologic structure and the 

 source and transportation of sediments. 



ROCK BOTTOM AREAS 



The rocks of Santa Monica Bay can be divided into three 

 groups; rocks in place (or bedrock), transported rock and 

 gravel, and authigenic rock. 



Rocks in Place 



The rock outcrops rise as irregular and scattered mounds 

 on the outer shelf south of Santa Monica Canyon, and occur in 

 an elongated tract close to the Malibu shore as shown in 

 Figure 13. The Appendix lists the samples of rock believed 

 to be in place and describes their lithology. In addition 

 to the samples obtained during the present survey, Emery and 

 Shepard (1945) obtained a few samples of rock from the walls 

 of both submarine canyons. The U, S. Coast and Geodetic 

 Survey "smooth sheets" show rocky bottom along the Malibu 

 coast and off Palos Verdes Hills. Johnson (1940b) made a 

 detailed chart of the rocky (bedrock and gravel) seafloor in 

 the nearshore zone along the coast of Malibu and Santa Monica. 

 No rocks were dredged along this part of the coast dviring the 



