314 CLEMENTS 



are the wave-cut terraces so beautifully shown on the Palos Verdes Hills 

 and on all the present islands with the exception of Santa Catalina Island, 

 on which they are obscure. On Palos Verdes Hills there are 13 main 

 terraces and two minor ones, the highest being 1325 feet above sea level, 

 and the lowest 150 feet above (Woodring, 1935). Smith (1898) re- 

 corded 23 terraces on San Clemente Island, although Lawson (1893) 

 listed only 19. The highest of these is 1,500 feet above sea level, with 

 those higher than 1,320 feet rather indistinct. San Nicolas and Santa 

 Barbara islands are distinctly terraced, but being at present only 890 

 and 635 feet above sea level respectively, they must have been completely 

 submerged when the higher terraces were being cut on the other islands. 



The terraces on the northern group of islands have been less inten- 

 sively studied than those of the southern group, although all the islands 

 show obvious terracing. The highest recorded on Santa Cruz Island 

 is at 750 feet above sea level (Bremner, 1932). Since the summit of 

 Anacapa, which has an elevation of 930 feet above sea level, is a wave-cut 

 surface, it is logical to believe that all the northern islands were sub- 

 merged at least to that level, and probably to the highest level recorded 

 on any of the islands. Certainly Anacapa and San Miguel were com- 

 pletely submerged, and Santa Cruz and Santa Rosa greatly reduced in 

 size at the time of the cutting of the highest terraces. 



Only on Santa Catalina Island is there a question regarding the 

 presence of wave-cut terraces. Lawson (1893) declared that no ter- 

 races existed, and that this and the evident stream-cut topography indi- 

 cated a very different history for this island from that of San Clemente 

 or Palos Verdes Hills. In other words, he believed that Santa Catalina 

 Island had been emergent while the others had been submergent. Smith 

 seemed more or less in agreement with this in his earlier paper (1897), 

 although he pointed out some possible terracing. In a later paper (1933), 

 however, he came out vigorously for the idea that Santa Catalina had 

 been subjected to the same wave action as the others, and stated that 

 because of its more resistant rocks, the terraces developed were not as 

 striking in appearance as on other islands. Shepard, Grant, and Dietz 

 (1939) upheld Lawson's view. 



During World War II, the United States Army Engineer Corps 

 made new topographic maps of Santa Catalina Island on a scale of 

 1 :25,000, and with a contour interval of 50 feet. Carefully constructed 

 profiles at several places suggest terraces at a number of elevations 

 (Clements, 1948), with the highest at approximately 1,400 feet above 

 sea level. A study of aerial photographs of the island, furnished through 



