130 CORAL FORMATIONS. 
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, p. 118, 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 
coral commenced to grow, there was, at the least, as the facts show, 
15,000 square miles of land, or nearly three times the present extent 
of surface. 
B. Lagoons of Atolls. 
We pass from these remarks on the channels and seas within bar- 
rier 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 con- 
tinued a step further, would produce the lagoon island. Nanuku is 
actually a lagoon island, with a single 
Fig. 4. mountain peak still visible; and Nuku- 
ois 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 Caro- 
lines to the north. The Gambier Group, 
near the Paumotus, appears to have af- 
forded the philosophical mind of Mr. Dar- 
ete ae ea win the first hint with regard to the origin 
of the atoll; the contrast, and, at the same 
time, the resemblance, was striking; the conclusion was natural 
Dp? 
and most happy.* As some interest is connected with the history 
* Captain Beechey, in his voyage in the Pacific, implies this resemblance, when he 
says of the Gambier Group, which he surveyed, ‘“ It consists of five large islands and 
