230 CORAL AT^D ATOLLS 



I am quite convinced, as a reKSult of watching the Cocos- 

 KeeHng atoll for fifteen months, that these temporary phases 

 are misleading, for there is no evidence to show that they 

 represent the normal process of development. The observa- 

 tion can therefore carry no more weight when urged to support 

 the theory of solution than when it was used as evidence of 

 the reality of subsidence. 



With regard to the position of the islets on the reef, it will 

 be pointed out, in studying the development of the atoll, that 

 this is entirely the outcome of the force of the waves which 

 first raised the islets, and the subsequent seaward growth of 

 the reef edge. 



Since the examination of the fully developed atoll lends no 

 support to this theory, it is natural to inquire whether the 

 study of its earlier stages will yield any evidence in favour of 

 the theory that its lagoon is caused by solution. One of 

 the most important additions to the study of coral structures 

 was made by Admiral Sir W. J. L. Wharton, who pointed out 

 that the great reefs of the China Sea, and elsewhere, had an 

 atoll form when far below the surface of the sea. These 

 ringed reefs are not in reality "drowned atolls," but are reefs 

 in the process of development, but it is difficult to see how 

 solution can possibly produce the condition found in them. 



From my prolonged observations of the Cocos-Keeling 

 atoll, I am convinced that the theory of " solution " does not 

 at all account for its development, its present features, or its 

 future history. 



Not only does no feature of the atoll yield any support 

 to the theory, but a great many of them definitely contradict it. 

 The lagoon shore is steadily gaining on the lagoon, all round 

 the atoll ring. The lagoon is steadily shoaling by the deposition 

 of sand brought into the lagoon by currents. Calcium carbo- 

 nate is being deposited in the lagoon, making beach sandstone 

 and conglomerate, and causing the old dead fragments to 

 become harder, and heavier, than they were during life. The 

 dead colonies of coral are not dissolved and removed from the 

 lagoon, for it is definitely known that great numbers of such 



