268 CORALS AND CORAL ISLANDS. 
The fact that the submerged reef is often much prolonged 
from the capes or points of a coral island, accords well with 
these views. These points or capes correspond to points in 
the original land, and often to the lme of the prominent 
ridge; and it is well known that such ridge limes often ex- 
tend a long distance to sea, with slight inclination compared 
with the slopes or declivities bounding the ridge on either 
side. 
The derivation of the forms of reef islands from a former 
mountain range is further sustained, according to Darwin, by 
the occurrence of coral islands or reefs in chains, like the peaks 

20 of an ind to a mile. 
MENCHICOFF ATOLL. 
of such a range. He gives as an example Menchicoff atoll, of 
the Caroline Archipelago, which consists of three long loops 
or lagoon islands, united by their extremities, and which fur- 
ther subsidence might reduce to three islands. 
Darwin, in his account of the Maldives, points out indica- 
tions of a breaking up of a large atoll into several smaller 
atolls. The land with many summits or ranges of heights 
may at first have had its single enclosing reef; but as it sub- 
sided, this reef, contracting upon itself, may have encircled 
separately the several ranges of which the island consisted. 
