Ch. VI. DISTRIBUTION OF CORAL-REEFS. 
165 
On the distribution of the different classes of reejs. 
■ — Having made the foregoing preliminary remarks, I 
will now consider how far the distribution of the dif- 
ferent kinds of coral-islands and reefs corroborates our 
theory. A glance at the map shows that the reefs 
which are coloured blue and red, and which are believed 
to owe their origin either to widely different move- 
ments, or in the case of the red to a stationary condition, 
are not indiscriminately mingled together. Atolls and 
barrier-reefs, as may be seen by the two blue tints, 
generally lie near each other ; and this would be the 
natural result of both having been produced by the same 
movement of subsidence. Thus, all the Society Islands 
are encircled by barrier-reefs ; and to the N.W. and 
S.E . there are several scattered atolls. To the eastward 
lies the great Paumotu or Low Archipelago consisting 
entirely of atolls ; and still further to the N.E., we meet 
with the Mendana or Marquesas Islands, which, from 
their abrupt and deeply indented shores, Dana 1 be- 
lieves have probably subsided ; though hardly any coral- 
reefs exist there, which might have afforded additional 
evidence of subsidence. In the midst of the Caroline 
atolls, there are three fine encircled islands. The 
northern point of the barrier-reef of New Caledonia 
apparently forms, as before remarked, a great atoll. 
The Australian barrier is described as including both 
atolls and small encircled islands. Captain King 2 
1 Corals and Coral Islands, 1872, p. 325. 
2 Sailing Directions, appended to vol. ii. of his Surveying Voyage 
to Australia. 
