Geological Mop 



67 



slate, were found in Santa Monica Bay 

 (Terry, Keesling, and Uchupi, 1956). 



Geological Map 



The most useful method of presenting 

 lithological information is in the form of a 

 geological map. Preliminary versions pub- 

 lished in 1951 and 1954 have been brought 

 up to date inthe accompanying map (Fig. 

 62) which is based not only on the sea floor 

 samples but on data from the mainland and 

 islands. Sources for the latter are as follows: 

 Los Coronados (Emery, Butcher, Gould, and 



Shepard, 1952), San Clemente (Smith, 1898), 

 Santa Catalina (Smith, 1897; Woodford, 

 1924), Santa Barbara (Kemnitzer, 1933; 

 Grady, in preparation), San Nicolas (Kem- 

 nitzer, 1933; Norris, 1951), Anacapa (Yates, 

 1890; Scholl, 1959), Santa Cruz (Bremner, 

 1932; Rand, 1933), Santa Rosa (Kew, 1927; 

 Bremner, 1933), San Miguel (Bremner, 

 1933), and general northern islands (Red- 

 wine, 1952). 



Basement rock in the region is mostly 

 schist of Mesozoic or even pre-Cambrian 

 age. Granitic basement rocks are known 

 only on Santa Cruz Island. Thus, the dis- 

 tribution of these basement rock types 



Figure 62. Geological map of sea floor and adjacent land. Revised from Emery (1951, \954d, Fig. 1). 



