ORIGIN OF THE A TOLL. 



227 



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 facis 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 



GAMBIEK ISLANDS. 



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 

 mode of origin may evidently be true of all atolls ; for, with 

 the exception of the points of high land in the inner waters, 

 there is no one essential character distinguishing many of the 

 eastern Feejee Islands from the Carolines to the north. The 

 Gambier Group, near the Paumotus, appears to have afforded 



Q 2 



