ORIGIN OF TUE BARRIER REEF. 2G3 



on the contrary, their non existence is incompatible with the 

 mode of action going on. They afford the strongest support 

 to the theory. 



A wide, flat reef, continuous over extensive reef-grounds, 

 could be formed only upon a nearly level bank, where there 

 were consequently no hills to pour in detritus and otherwise 

 retard growth over the interior portions ; and even then it 

 would be liable to be cut up by the action of currents, destroy- 

 ing growing corals over its interior parts. 



From these considerations it is evident that a barrier reef 

 indicates approximately the former limits of the land enclosed. 

 The Exploring Isles (Feejee chart), instead of an area of six 

 square miles, the whole extent of the existing land, once cov- 

 ered three hundred square miles ; and the outline of the for- 

 mer land is indicated by the course of the enclosing reef. A 

 still greater extent may be justly inferred. For a barrier, 

 as subsidence goes on, gradually contracts its area, o.ving to 

 the fact that the sea bears a great part of the material inward 

 over the reefs ; and, consequently, the declivity forming the 

 outer limit of the sub-marine coral formation has a steep angle 

 of inclination. 



In the same manner it follows that the island Nanuku, in- 

 stead of one square mile, extended once over tivo / undred 

 square miles, or had two hundred times the present area of 

 high land. Bacon's Isles once formed a large triangular 

 island of equal extent, though now but two points of rock 

 remain above the water. 



The two large islands in the western part of the group, 

 Vanua Levu and Viti Levu, have distant barriers on the west- 

 ern side. Off the north point of the former island, the reef be- 

 gins to diverge from the coast, and stretches off from the 

 shores till it is twenty and twenty-five miles distant ; then, 



