SUBSIDENCE OF THE PACIFIC 



its features so tame, its supply of fresh water so small, 

 and of salt water so large, that whoever should build his 

 cottage on one of them would probably be glad, after a 

 short experience, to transfer it to an island of larger 

 dimensions, like Tahiti or Upolu, one more varied in 

 surface and productions; that has its mountains and pre- 

 cipices ; its gorges and open valleys ; leaping torrents not 

 less than surging billows; and forests spreading up the 

 declivities, as well as groves of palms and corals by the 

 shores. ' ' 



Subsidence in the Pacific 



The changes of level at the bottom of the Pacific Ocean 

 are discussed in the fifth chapter of Corals and Coral 

 Islands : 



" It has been shown that atolls, and to a large extent 

 other coral reefs, are registers of change of level. From 

 the evidence thus afforded the bottom of a large part of 

 the Pacific Ocean is proved to have undergone great os- 

 cillations in recent geological time. In this direction, 

 then, we find the grandest teachings of coral formations. 

 The facts surveyed give us a long insight into the 

 past, and exhibit to us the Pacific once scattered over 

 with lofty lands, where now there are only humble monu- 

 mental atolls. Had there been no growing coral, the 

 whole would have passed without a record. These per- 

 manent registers exhibit in enduring characters some of 

 the oscillations which the ' stable ' earth has since under- 

 gone. 



" From the actual size of the coral reefs and islands, 

 we know that the whole amount of high land lost to the 

 Pacific by the subsidence was at the very least fifty thou- 

 sand square miles. But since atolls are necessarily smaller 

 than the land they cover, and the more so the further 

 subsidence has proceeded ; since many lands, owing to 

 their abrupt shores, or to volcanic agency, must have had 

 no reefs about them, and have disappeared without a 

 mark; and since others may have subsided too rapidly 

 for the corals to retain themselves at the surface, it is 

 obvious that this estimate is far below the truth. It is 

 apparent that, in many cases, islands now disjoined have 

 been once connected, and thus several atolls may have 



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