490 W. M. DAVIS SUBSIDENCE OF REEF-ENCIRCLED ISLANDS 



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Submarine banks in the Pacific and Indian oceans 528 



The Seychelles bank 531 



Recent origin of great ocean depths 532 



Disappearance of detritus from deeply eroded islands 533 



Conditions of reef establishment 533 



Clif t islands in the coral seas 533 



Reefs around deeply eroded islands 534 



The submerged cliffs of reef-encircled islands 536 



Absence of reefs on coasts of emergence 537 



Reefless coasts in the Australasian archipelagoes 537 



The reefless coast of southeastern India 539 



Reefs on coasts of submergence 540 



Reefs on coasts of recent and continued submergence 542 



Smothered reefs on coasts of less recent submergence 542 



Reefs on coasts of emergence, afterward submerged 543 



The half-submerged cliffs of New Caledonia 545 



Unequal depths of lagoons and banks 549 



The requirements of the Glacial-control theory 549 



The expectable form of abraded platforms 550 



The requirements of the subsidence theory 552 



The smoothness and depth of lagoon floors 553 



Variations in the depth of submarine banks 555 



Banks around reef -free clif t islands 555 



The depth of barrier-reef lagoons ....'.... '558 



The volume of reefs 560 



Contrasts of the central and the western Pacific 560 



Average and individual values of lagoon depths 561 



The detailed form of island spur ends as evidence for intermittent subsi- 

 dence 562 



The origin of atolls 564 



Indirect evidence from barrier reefs 564 



The Funafuti boring 565 



The Bermuda boring 566 



Depths of atoll lagoons 568 



Regional or local subsidence , 569 



Molengraaff 's views as to the local subsidence of volcanic islands 571 



References 572 



Darwin's Verifications of the Theory of Subsidence 



unexplained confusion replaced by reasonable order 



It has sometimes been objected to Darwin's theory of npgrowing coral 

 reefs on intermittently subsiding foundations, that he gave no independ- 

 ent proof of the subsidence which he postulated ; but as a matter of fact he 

 brought forward three kinds of confirmatory evidence for it. He showed, 

 first, that the sequence of forms which includes fringing reefs, barrier 



