THE BUILDING OF AN ISLAND. 95 



evidence regarding the lesser ones is very obscure, so that we have here our 

 first direct knowledge of tremendous crustal movements. 



"The whole uplift took place during the latter half of September, 1899, 

 being practically continuous during that time, with occasional sharp shocks; 

 it caused great waves in the bay, probably as the water rushed out from it, for 

 its bottom also was raised, as is proven by the appearance of new reefs and 

 islands in its confines. Today one may walk for miles along its shores, over 

 dry beaches, high above the reach of the highest storm wave, crunching under 

 foot the yet undecomposed seaweed and the whitened barnacles clinging still 

 to the rocks on which they once grew, and around which the surf once rolled 

 continuously. The evidence of the uplift is complete. Old sea caves and 

 wave-cut cliffs, areas where the plants have not yet had time to gain a foothold, 

 all help to tell the story. If one has wondered how the sediments of old sea 

 bottoms may form the summits of the highest mountains, here is an illustra- 

 tion of a force at work adequate to lift them to such a height. 



" The two weeks during which this uplift occurred was a period of almost 

 uninterrupted earthquakes in the Yukutat Bay vicinity. As reported by the 

 missionary at the Indian Settlement at the mouth of the bay, and by prospectors 

 encamped near by, some of the shocks were of great violence." 



To the evidence of such examples may be added that of the raised beaches 

 found in several parts of the world, which show that elevations have taken 

 place in quite recent geological times. 



The raised beaches of Norway are well-known examples, and a recent 

 writer has given an account of several such beaches near Taltal, in the north 

 of Chili, where he found three very distinct levels, namely, at fifteen feet, eightv 

 feet and two hundred feet, respectively, above the present sea level, which 

 were marked bv the presence of boulders, well-preserved sea-shells, and caves 

 of wave-erosion, pointing evidently to three successive upliftings of the coast 

 at the place named. 



We must remember, too, that an elevation sufficient to balance the wearing 

 down of an island might take place without its being possible to observe it. 

 Geological processes are for the most part extremely slow, we have seen that 

 four centuries would probably be required to lower St. Croix by a single inch ; 

 where would the means be found to measure a rise of an inch at the end of 

 that time, should it have taken place ? If it were two inches, there would be 

 a balance in favour of the island ; it would be rising, but how could that be 

 discovered ? 



The earlier geologists supposed that the processes by which the earth's 

 crust has been built up had been formerly very active, but had in the present 

 day nearly ceased. Sir Charles Lyell, in his " Principles of Geology," by 

 calling attention to the nature of geological processes and by pointing out 

 similar changes that are taking place at the present time, showed that this view 

 was erroneous, but he probably went too far in the opposite direction in con- 

 cluding that the story had been always the same since the dawn of geological 



