Smith.] 



Islands of Southern California. 



213 



Its outlines are still sharp and clear, but it is only a remnant of its 

 original form ; for its width before it had been cut into by the 

 succeeding lower terraces could not have been greatly less than 

 that of the present submarine terrace, so that we may assume it to 

 have been at least two miles. If, then, the best developed and 

 preserved of the elevated terraces are at the present time compara- 

 tively mere remnants, as on the lower slopes of the ocean facing of 

 San Pedro Hill and San Clemente Island, where the angle of slope 

 was low (5 to 7 ), and the conditions in general more than usually 

 favorable to terrace development and preservation, we could scarcely 

 expect to find pronounced elevated terraces, or in most cases even 

 traces of terracing, where the original angle of slope was high 

 (25 or more). The present period of wave cutting has been a 

 long one, to judge from the development of the submarine platform, 

 so that there has been ample opportunity for the obliteration 

 through wave action of the comparatively narrow terraces which 

 would be formed on the rugged coast line. This submarine terrace 

 is pronounced off Santa Catalina Island, and in its development cliffs 

 have been produced running up to 1,000 feet or more in height. 

 In any case, it is certain that, whatever height the present actual 

 sea-cliff attains, on that shore no terraces can be found below its 

 upper edge. 



Other things being equal, cliff cutting is more rapid on the side 

 from which the greatest waves come. That this factor, however, 

 (beyond a certain minimum fetch of the waves whiHh must be 

 assumed in order that they may develop in sufficient size for active 

 cutting) is not so important as the slope of the surface on which 

 the cutting takes place, is seen on San Nicolas Island. Here the 

 side from which the greatest waves come exhibits only a narrow 

 submarine terrace, and no elevated terraces have been recorded on 

 this side of the island; while on the northern or landward side this 

 submarine terrace is of remarkable development (though here best 

 developed where there is the greatest exposure to the waves from 

 the open ocean). 



In the writer's opinion, whatever movements may have taken 

 place since the first elevation of San Clemente and San Nicolas, 

 these have been insufficient to prevent the possibility of terracing on 



