Islands and Coral-reefs of the Fiji Group. 237 



eitlier its volcanic or coral (elevated reef) origin : the shape of 

 the atoll being entirely due to mechanical action, and not 

 being connected in any way with the growth of the corals 

 which have found a footing upon reef-flats formed by atmo- 

 spheric agencies or by the action of the sea. 



So that, as far as we can judge from the case of the Fiji 

 Islands, the shape of the atolls and of the barrier reefs is due 

 to causes which have acted during a period preceding our 

 own. The islands of the whole group have been elevated, 

 and since their elevation have, like the northern part of 

 Queensland, remained nearly stationary and exposed to great 

 and prolonged denudation and erosion, which has reduced the 

 islands to their present height ; the platforms upon which the 

 barrier-reef corals have grown being merely the flats left by 

 the denudation and erosion of a central island of greater size 

 than that now left, while the atolls are similar flats from the 

 interior of which the islands have been eroded and the lagoons 

 of which have been continually scoured by the action of the 

 sea, the incessant rollers pouring a huge mass of water into 

 the lagoon, which finds its way out through the passages 

 leading into it. 



In the Fiji Islands the atolls and islands or islets, sur- 

 rounded in part or wholly by barrier reefs, have not been 

 formed by the subsidence and disappearance of this central 

 island, as is claimed by Dana and Darwin. The Fiji Islands 

 are not situated, as was supposed, in an area of subsidence, 

 but, on the contrary, they are in an area of elevation, so that 

 the theory of Darwin and of Dana is not applicable to the 

 islands and atolls of the Fiji group. 



What the age of the elevated reef of the Fiji is I am unable 

 to state ; its aspect and position show it to be of considerable 

 age, probably antecedent to the present period. In many ways 

 it resembles some of the late Tertiary elevated limestones 

 Avhich I have seen on the northern and southern coasts of 

 Cuba. The great thickness which the elevated coral-reefs 

 attain in this group, at least 800 feet, also shows that they 

 may have been deposited originally during a period of subsi- 

 dence, but not a period of subsidence taking place in our 

 epoch or which could have had any eftect in shaping the out- 

 line of the islands of the Fiji group and their accompanying 

 reefs. 



Whether the elevation of the Fiji group corresponds in time 

 with that of Northern Queensland I am unable to state. I 

 can only suggest that it is not improbable that the elevation 

 of Queensland and of the Pacific islands to the east, New 

 Caledonia, the Loyalty Islands, the Solomon, New Hebrides, 



