Ch. yi. distribution of coral-reefs. 
169 
the belief that these islands have recently subsided ; 
though not proving the fact. At Keeling atoll, however, 
I have described certain appearances, which seem 
directly to show that the surface subsided there during 
the late earthquakes. In the Caroline Archipelago, 
the island of Pouynipete (Plate I. fig. 7), from being en- 
circled by a great barrier-reef, must have subsided, in 
accordance with our theory ; and in the New South 
Wales Lit. Advert. Feb. 1835, there is an account of 
this island, (subsequently confirmed by Mr. Campbell,) 
in which it is said, * At the N.E. end, at a place called 
Tamen, there are ruins of a town, now only accessible 
by boats, the waves reaching to the steps of the houses.’ 
Hence it would appear that the island must have sub- 
sided since these houses were built. Mr.Halesalso states, 
from information acquired during the U.S. Exploring 
Expedition, that certain buildings on this island are 
now in the water: ‘what were once paths are now 
passages for canoes, and when the walls are broken down 
the water enters the enclosures.’ 1 Vanikoro, according 
to the Chevalier Dillon, is often violently shaken by 
earthquakes, and there, the unusual depth of the channel 
between the shore and the reef, the wall-like structure 
on the inner side of the reef, the small quantity of low 
alluvial land at the foot of the mountains, and the almost 
entire absence of islets on the reef, all seem to show 
that this island has not remained long at its present 
level. 2 At the Society Archipelago, on the other hand, 
1 Professor Dana also concludes from these facts that the island 
is subsiding ; see Corals and Coral Islands, 1872, p. 330. 
2 See Captain Dillon’s Voyage in search of La Peyrouse. M. 
