CHANNEL ISLAND REGION 321 



Nicolas and Santa Barbara Islands were completely submerged (see 

 Plate II). Santa Catalina Island may have remained high, a considerably 

 larger island than at present, although if the somewhat obscure terraces 

 have been properly interpreted in the earlier pages of this paper, it was 

 partially submerged like the others. 



Presumably it was during this inundation that dwarfing of the ele- 

 phants on the northern islands occurred, and the highest terraces were 

 cut on Palos Verdes, San Clemente, and Santa Catalina. This probably 

 was not later than the early part of late Pleistocene (Palos Verdes age), 

 perhaps during the Sangamon interglacial. 



As the Wisconsin ice sheets developed, sea level again fell, probably 

 accompanied once more by actual rise of the land. During intervals of 

 stillstand in the general emergence, the numerous terraces were cut and 

 remain as mute witnesses to the presence of the former shorelines. The 

 Palos Verdes (late Pleistocene) fossils from the lowest terrace indicate 

 that the withdrawal of the sea was also accomplished in late Pleistocene 

 time, before the end of the Wisconsin glacial age. 



With the melting of the Wisconsin ice sheets, the beginning of which 

 is variously estimated at from 11,000 to 25,000 years ago, and which is 

 presumed to be still in progress, sea level should again be rising. On the 

 other hand, the Channel Island region itself may also be rising. Recent 

 seismic activity in the area (Clements and Emery, 1947) indicates cer- 

 tainly that it is by no means quiescent. Whether or not the region is 

 rising faster than sea level can be answered only in the future. 



LITERATURE CITED 



Arnold, R. 



1903. The paleontology and stratigraphy of the marine Pliocene and Pleisto- 

 cene of San Pedro, California. Calif. Acad. Sd. Mem. vol. 3, 420 pp. 



Bailey, T. L. 



1943. Late Pleistocene Coast Range orogenesis in southern California. Geol. 

 Soc. America. Bull. vol. 54, pp. 1549-1568. 



Bowers, S. 



1890. San Nicolas Island. Calif. State Min. Bur. Ann. Report No. 9, pp. 57-61. 



Bremner, C. St. J. 



1932. Geology of Santa Cruz Island, Santa Barbara County, California. 

 Santa Barbara Mus. Nat. Hist. Occas. Paper 1, 33 pp. 



1933. Geology of San Miguel Island, Santa Barbara County, California. 

 Santa Barbara Mus. Nat. Hist. Occas. Paper 2, 23 pp. 



Chaney, R. W. and H. L. Mason 



1934. A Pleistocene flora from Santa Cruz Island, California. In Studies of 

 the Pleistocene Paleobotany of California. Carnegie Inst. Washington. 

 Pub. No. 415 (Contrib. Paleontology), pp. 1-24. 



