PACIFIC AND BEERING’S STRAIT. 
189 
a Break of the sea, outside which the descent is very steep, 
a h Descent of the sides of several islands. 
i ditto ditto off the points which are shallower, 
s, s Soundings upon coral, 
o, o No bottom at these depths. 
Fig. 2. 
a a Habitable part of the island. 
b, b Greatest depth at which it is supposed the coral animals can commence their opera 
tions. 
All these islands are situated within the trade-wind, with the ex- 
ception ofOeno, which is only on the verge of it, and follow one general 
rule in having their windward side higher and more perfect than the 
other, and not unfrequently well wooded, while the other is only a 
half-drowned reef, or wholly under water. At Gam bier and Matilda 
Islands this inequality was very conspicuous, the weather side of both 
being wooded, and of the former, inhabited, while the other sides were 
from twenty to thirty feet under water, where they might be perceived 
equally narrow, and well defined. It is on the leeward side also that 
the entrances into the lagoons generally occur, though they are some- 
times situated in a side that runs in the direction of the wind, as at Bow 
Island ; but I do not know of any one being to windward. The fact, 
if it be found to be general with regard to other coral islands, is curious, 
and is not fully accounted for by the continued operation of the trade- 
wind upon its side, as the coincidence would suggest. After the reef 
has arrived at the surface of the sea, it is easy to conceive what would 
be the effect of the trade-wind ; but it does not seem possible that its 
influence could be felt so far under water as some of the reefs are 
situated. 
All the points or angles of these islands descend into the sea with 
less abruptness than the sides, and, I think, with more regularity. The 
Wedge-shaped space that the meeting of the two sides would form in 
the lagoon is filled up by the ledges there being broader ; in such 
places, as well as in the narrow parts of the lake, the coralline are in 
greater numbers, though, generally speaking, all the lagoons are more 
nr less incumbered with them. They appear to rise to the surface in 
CHAP. 
VIII. 
Feb. 
1826. 
