Cii. VI. 
RECAPITULATION. 
195 
marginal and central reefs in the Maldiva atolls — the 
union of some atolls as if by a ribbon — the apparent 
disseverment of others — the ordinary outline of groups 
of atolls and their forms — are all thus explained. We 
thus understand the occurrence in both atolls and 
barrier-reefs of portions, or of the whole, in a dead and 
submerged condition, though still retaining the outline 
of a living reef. The existence of breaches through 
barrier-reefs in front of valleys, though separated from 
them by wide spaces of deep water, can be similarly ex- 
plained. It confirms our theory that we find the two 
kinds of reefs formed through subsidence generally situ- 
ated near each other and at a distance from the spaces 
where fringing-reefs abound. On searching for other 
evidence of the movements assumed by the theory, 
we find marks of change in atolls and in barrier-reefs, 
and of subterranean disturbances beneath them ; but 
from the nature of things, it is scarcely possible to 
find direct proofs of subsidence, although some appear- 
ances are strongly in favour of it. On the fringed 
coasts, however, the frequent presence of upraised 
marine remains belonging to a recent epoch, plainly 
shows that these coasts have been lately elevated. 
Finally, when the two great types of structure, 
namely barrier-reefs and atolls on the one hand, 
and fringing-reefs on the other, are laid down on a 
map, they offer a grand and harmonious picture of 
the movements w'hich the crust of the earth has 
undergone within a late period. We there see vast 
areas rising, with volcanic matter every now and then 
