Smith.] 



Islands of Southern California. 



20 1 



off China Point. Thus the development about San Clemente 

 corresponds with that of the elevated terraces, since they are best 

 developed on the southwestern facing, and but little developed on 

 the northeastern side of the island. From a map of San Clemente 

 on which the principal elevated shore lines have been plotted, it is 

 readily seen that during the various stages in the elevation of the 

 island the greatest width of the submarine platform has always 

 been, as now, at the extremities of the island. 



The platform is broadest on the landward side of San Nicolas, 

 where the slopes are gentle, and narrowest on the abrupt, ocean 

 side, where it averages between a mile and a half and two miles in 

 width. It reaches its maximum width off the salients at either end 

 of the island, being about fifteen miles wide at the end facing the 

 ocean, though considerably narrower than this off the landward 

 end. The submarine platform is wider about San Nicolas than 

 about any of the other islands. This is to be accounted for in part 

 by the greater exposure to wave action, and in part by the softness 

 of the rocks of which the island is composed. 



The average width of the platform about Santa Barbara Island 

 is between two and three miles. Its greatest development is on 

 the east and west, on the slopes away from the main axis, where 

 the cliffs are lowest. The maximum width is on the west, facing 

 the open ocean. 



In the case of all the islands of the northern group, the average 

 distance of the 600-foot contour from the shore is greater on the 

 north than on the south. The slopes of San Miguel Island are 

 most abrupt on the south. The submarine platform reaches a 

 maximum width of some thirteen miles to the northwest of this 

 island; while it is narrowest to the southwest of the western end of 

 the island, having a minimum width here of about three miles. 



The distance to the 600-foot contour on the north of Santa 

 Rosa Island ranges from about five to about eight miles. The 

 platform is narrowest on the southwest, where the range is from 

 two and a half to five miles. The maximum width is to the south- 

 east, where it is probably due to structural conditions. If Santa 

 Rosa and San Miguel Islands together constitute a faulted crust 

 block, as already suggested, with the fault scarp on the southwest, 



