226 CORALS AND CORAL ISLANDS. 



From these considerations it is evident that a barrier reef 

 indicates approximately the former limits of the land inclosed. 

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

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

 covered three hundred square miles ; and the outline of the 

 former land is indicated by the course of the inclosing reef. 

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

 subsidence goes on, gradually contracts its area, owing 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 incUnation. 



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

 stead of one square mile, extended once over two hu?idred sqyi?LYt 

 miles, or had two hundred times the present area of high land. 

 Bacon's Isles once formed a large triangular island of equal ex- 

 tent, 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 western 

 side. Off the north point of the former island, the reef begins 

 to diverge from the coast, and stretches off from the shores till 

 it is twenty and twenty-five miles distant ; then, after a narrow 

 interruption, without soundings, the Asaua islands commence 

 in the same line, and sweep around to the reef which unites 

 with the south side of Viti Levu ; and, tracing the reef along 

 the south and east shores, we find it at last nearly connecting 

 with a reef extending southward from Vanua Levu. Thus 

 these two large islands are nearly encircled in a single belt ; 

 and it would be doing no violence to principles or probabilities 

 to suppose them once to have formed a single island, which 

 subsidence has separated by inundating the low intermediate 

 area. The singular reef of Whippey harbour, page 210, is fully 

 explained by the hypothesis. We may thus not only trace out 

 the general form of the land which once occupied this large 

 area (at least 10,000 square miles), but may detect some of its 

 prominent capes, as in Wakaia and Direction Island. The 

 present area is not far from 4,500 square miles. 



