236 THE JOURNAL OF GEOLOGY. 



dation between the Miocene uplift and the depression which permitted 

 the deposition on the lower flanks of the hill of the formations which 

 paleontologists recognize as of Pliocene age. The recovery from this 

 Pliocene depression is the uplift which is registered in the elevated 

 strands of the hill." The uplift following the Pliocene depression is 

 regarded as Pleistocene. This conclusion is of course warranted, if 

 the Pliocene strata involved are known to belong to the closing stages 

 of the Pliocene period. Otherwise it does not appear that the con- 

 clusion is a necessary one. Pleistocene strata are referred to as over- 

 lying the Pliocene, and as belonging to a recent stage of the uplift. 

 Between the Pliocene and the Pleistocene no evidence of subaerial 

 denudation exists. ~^ 



On the west side of San Clemente Island seventeen well marked 

 terraces occur, the highest at an elevation of 1320 feet. These ter- 

 races are from 200 to 1500 feet in width. There are less distinct ter- 

 races up to a height of 1500 feet. "The total amount of horizontal 

 sawing which has been effected on the slopes of the island by wave 

 action during its elevation through the last 1320 feet," is more than 

 two miles. 



Santa Catalina Island is of about the same size, trend, and height 

 as San Clemente. It has a position midway between San Pedro Hill 

 and San Clemente; but on Santa Catalina "there is no trace of an 

 elevated wave-cut terrace, sea-cliff, or strand line of any kind observ- 

 able." Furthermore, "The stream topography of the island is very 

 much more advanced, /. e., much more ancient than that of either San 

 Pedro Hill or San Clemente." 



The absence of terraces and sea-cliffs cannot be attributed to the 

 character of the rock, and their absence is in harmony with the con- 

 dition of the stream valleys, which indicate that the island has not 

 been below the sea in recent times ; that is, " Santa Catalina has not 

 been subjected to the uplift which has affected the two prominent 

 insular masses, one twenty-five miles to the north of it, and the other 

 twenty-five miles to the south of it." Not only has Santa Catalina not 

 been elevated while San Pedro and San Clemente were undergoing 

 the great uplifts which have been mentioned, but it is believed to have 

 actually sunk while these other land masses were being lifted. The 

 evidence of sinking is found in the drowned valleys of certain parts of 

 the coast, and in the falls and rapids which mark the termini of the 

 streams of other parts. Santa Catalina would appear to be situated in 



