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University of California. 



[Vol. i. 



independently of the petrographical character of the mass operated 

 upon. The bearing of this will be apparent when we come to con- 

 sider the case of Santa Catalina Island. 



Uplift.— The description of the physiographic features of San 

 Clemente will leave'no doubt in the mind of the appreciative reader as 

 to the interpretation which is to be placed upon the terraces of the 

 island. They are unquestionably sea terraces, and represent elevated 

 ocean strands. The character of the terraces, indicates that the 

 uplift progressed by stages, and that many of these stages represent 

 a long-continued practical permanency of the relations of land and 

 sea. There is no implication, however, that the passage from stage 

 to stage was per saltnm. The change from one stage to another 

 was probably gradual, and it is entirely compatible with the results 

 now observable that the actual progress of the uplift from stage to 

 stage was very slow. The full number of these stages is probably 

 greater than is now registered in the elevated strands of the island, 

 and many more strands remain to be discovered by more careful 

 examinations in future. No less than twenty-two strands have, 

 however, been recognized, as stated on a previous page. These 

 doubtless have very different values as regards the time occupied 

 in the recession of their respective sea-cliffs, the breadth of the sev- 

 eral terraces varying greatly. The partial obliteration of most of 

 the terraces, by the recession of the later cliffs below them, prevents 

 our obtaining any correct figures for the amount of horizontal cut- 

 ting done at any given stage, or for the total amount of cutting 

 done at all stages. That some general idea, however, of the work 

 done by the waves during the uplift of the island might be given, 

 the writer has measured the maximum widths of seventeen promi- 

 nent terraces shown on the Coast Survey map, and finds that their 

 sum is about two miles. Some of the outer portions of a few of 

 these terraces may, possibly, be slopes not properly to be regarded 

 as wave-cut, but the majority of them are but the remnants of once 

 much broader wave-cut terraces, which have been reduced by the 

 encroachment of cliffs of later stages of the uplift. Two miles is, 

 therefore, far within the minimum value of the total amount of hori- 

 zontal sawing which has been effected in the slopes of the island by 

 wave action during its elevation through the last 1,320 feet. If we 



