Sect. II. RATE OF GROWTH. 101 



of thirty-four years, from being, as described by the 

 crew of a wrecked whaling vessel, a ' reef of rocks,' 

 into a lagoon-island fourteen miles in length, with 

 'one of its sides covered nearly the whole way with 

 high trees.' 1 The islets, also, on Keeling atoll, it has 

 been shown, have increased in length, and since the 

 construction of an old chart, several of them have 

 become united into one long islet : but in this case, 

 and in that of Matilda atoll, we have no proof that 

 the foundation of the islets, namely the reef, has 

 increased in breadth, although it must be allowed that 

 this is probable. 



I think, therefore, in regard to the possible rate of 

 outward growth of coral-reefs, but little importance 

 need be attached to the fact that, certain reefs in the 

 Eed Sea have not increased during a long interval of 

 time, or to other similar cases, such as that of Ouluthy 

 atoll in the Caroline group, where every islet, described 

 a hundred years before by Cantova, was found in the 

 same state by Lutke. 2 For it cannot be shown that, 

 in these cases, the conditions were favourable to the 

 vigorous and unopposed growth of the corals living 

 in the different zones of depth, and that a proper basis 

 for the extension of the reef was present. These 

 conditions must depend on many contingencies, and 

 a basis within the requisite depth can rarely be pre- 



1 Beechey's Voyage to the Pacific, ch. vii. and yiii. 



2 F. Lutke's Voyage autour du Monde. In the group Elato, how- 

 ever, it appears that what is now the islet Falipi, is called in Cantora's 

 Chart, the Banc de Falipi. It is not stated whether this has been 

 caused by the growth of coral, or by the accumulation of sand. 



