The whole group of the _Thousand Islands_, and indeed the greater part
of all those whose surfaces are flat, in the neighbourhood of the
equator, owe their origin to the labours of that order of marine worms
which Linnaeus has arranged under the name of _Zoophyta_. These little
animals, in a most surprising manner, construct their calcareous
habitations, under an infinite variety of forms, yet with that order and
regularity, each after its own manner, which to the minute inquirer, is
so discernable in every part of the creation. But, although the eye may
be convinced of the fact, it is difficult for the human mind to conceive
the possibility of insects so small being endued with the power, much
less of being furnished in their own bodies with the materials of
constructing the immense fabrics which, in almost every part of the
Eastern and Pacific Oceans lying between the tropics, are met with in
the shape of detached rocks, or reefs of great extent, just even with
the surface, or islands already clothed with plants, whose bases are
fixed at the bottom of the sea, several hundred feet in depth, where
light and heat, so very essential to animal life, if not excluded, are
sparingly received and feebly felt. Thousands of such rocks, and reefs,
and islands, are known to exist in the eastern ocean, within, and even
beyond, the limits of the tropics. The eastern coast of New Holland is
almost wholly girt with reefs and islands of coral rock, rising
perpendicularly from the bottom of the abyss. Captain Kent, of the
Buffalo, speaking of a coral reef of many miles in extent, on the
south-west coast of New Caledonia, observes, that "it is level with the
water's edge, and towards the sea, as steep to as a wall of a house;
that he sounded frequently within twice the ship's length of it with a
line of one hundred and fifty fathoms, or nine hundred feet, without
being able to reach the bottom." How wonderful, how inconceivable, that