either downwards or upwards, within a period not geologically remote.
It would appear also, that the elevatory and subsiding movements follow
nearly the same laws. Throughout the spaces interspersed with atolls,
where not a single peak of high land has been left above the level of
the sea, the sinking must have been immense in amount. The sinking,
moreover, whether continuous, or recurrent with intervals sufficiently
long for the corals again to bring up their living edifices to the
surface, must necessarily have been extremely slow. This conclusion is
probably the most important one which can be deduced from the study of
coral formations;--and it is one which it is difficult to imagine how
otherwise could ever have been arrived at. Nor can I quite pass over
the probability of the former existence of large archipelagoes of lofty
islands, where now only rings of coral-rock scarcely break the open
expanse of the sea, throwing some light on the distribution of the
inhabitants of the other high islands, now left standing so immensely
remote from each other in the midst of the great oceans. The
reef-constructing corals have indeed reared and preserved wonderful
memorials of the subterranean oscillations of level; we see in each
barrier-reef a proof that the land has there subsided, and in each
atoll a monument over an island now lost. We may thus, like unto a
geologist who had lived his ten thousand years and kept a record of the
passing changes, gain some insight into the great system by which the
surface of this globe has been broken up, and land and water
interchanged.
[1] These Plants are described in the Annals of Nat. Hist., vol. i.,
1838, p. 337.
[2] Holman's Travels, vol. iv. p. 378.
[3] Kotzebue's First Voyage, vol. iii. p. 155.
[4] The thirteen species belong to the following orders:--In the
Coleoptera, a minute Elater; Orthoptera, a Gryllus and a Blatta;
Hemiptera, one species; Homoptera, two; Neuroptera a Chrysopa;
Hymenoptera, two ants; Lepidoptera nocturna, a Diopaea, and a
Pterophorus (?); Diptera, two species.
[5] Kotzebue's First Voyage, vol. iii. p. 222.
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