264 CORALS AND CORAL ISLANDS. 



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, tra- 

 cing 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 harbor, 

 page 246, 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. 



The whole Feejee Group, exclusive of coral islets, includes 

 an area of about 5,500 square miles of dry land ; while, at the 

 period when the corals commenced to grow, there were, at least, 

 as the facts show, 15,000 square miles of land, or nearly three 

 times the present extent of habitable surface. 



III. LAGOONS OF ATOLLS. 



We pass from these remarks on the channels and seas 

 within barrier reefs, to the consideration of the seas or lagoons 

 of coral atolls. The inference has probably been already made 

 by the reader, that the same subsidence which has produced 

 the distant barrier, if continued a step farther, would produce 

 the lagoon island. Nanuku is actually a lagoon island, with 

 a single mountain peak still visible ; and Nuku Levu, north 

 of it, is a lagoon island, with the last peak submerged. This 



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