228 



University of California. 



[Vol. 2. 



San Clemente, San Pedro Hill, Santa Cruz, and Santa Rosa all 

 probably existed as islands, or in the case of Santa Cruz and Santa 

 Catalina, as two or more small islands. At this level the ocean 

 remained, cutting away the tops of these islands, till, in the case of 

 San Pedro Hill and perhaps of Santa Rosa, also, they were prob- 

 ably wholly truncated, leaving submarine banks, like those of the 

 region to-day. It is possible that San Nicolas was also above sea 

 level at that time, and has since been planed off to its present 

 lower level. Of San Clemente there remained a small nucleus, near 

 the center of the northern half of the island. Santa Catalina was 

 reduced to a small island lying to the north of the center of the 

 present larger division of the island, with, probably, one or more 

 distant rocks or smaller islands, toward the present extremities of 

 the island. Santa Cruz, at that time, probably existed as a single 

 narrow island, or a line of islands, with a length of at least seven 

 miles, and formed from the northern ridge of the western or main 

 division of the present island. Then, as now, Santa Cruz was 

 probably the highest, if not the largest, of the existing islands. 



This depression was followed by a post-Pliocene elevation, as 

 shown both by the present elevation of the Pliocene deposits, and 

 by the elevated coastal terraces. Dr. Lawson*has described one 

 general elevation of the coast in post-Pliocene times, while two 

 such elevations, both greater than the present, and with a depres- 

 sion of 1,200-1,500 feet between them, have been advocated by 

 Dr. Fairbanks.! A more thorough knowledge of the geology of 

 the coast as a whole can alone decide between these two hypoth- 

 eses. The writer is inclined, from present information, to the view 

 of one general elevation of the California coast in post-Pliocene 

 times, accompanied by minor oscillations, and by local differential 

 movements, such as that called for, for example, in the formation 

 of San Francisco Bay. According to Fairbanks, \ re-excavation 



*The P> 'St-Pliocene Diastrophism of the Coast of Southern California, 

 Bull. Dept. Geol., Univ. Calif., Vol. I, No. 4, 1893; and The Geoni' >rphogeny 

 of the Coast of Northern California, Bull. Dept. Geol., Univ. Calif., Vol. I, 

 No. 8, 1894. 



t Oscillations of the Coast of California during the Pliocene and Pleistocene, 

 Am. Geol., Vol. XX, October, 1897, pp. 213-245. 

 % Loc. cit., p. 245. 



