"THE VOYAGE OF THE BEAGLE" - читать интересную книгу автора (Darwin Charles)

over my collection I did not perceive the difference. The
globular extremities of the branches are of a pearly texture,
like the enamel of teeth, but so hard as just to scratch plate-
glass. I may here mention, that on a part of the coast of
Ascension, where there is a vast accumulation of shelly sand,
an incrustation is deposited on the tidal rocks by the water
of the sea, resembling, as represented in the woodcut, certain
cryptogamic plants (Marchantiae) often seen on damp
walls. The surface of the fronds is beautifully glossy; and
those parts formed where fully exposed to the light are of a
jet black colour, but those shaded under ledges are only grey.
I have shown specimens of this incrustation to several
geologists, and they all thought that they were of volcanic
or igneous origin! In its hardness and translucency -- in
its polish, equal to that of the finest oliva-shell -- in the
bad smell given out, and loss of colour under the blowpipe -- it
shows a close similarity with living sea-shells. Moreover, in
sea-shells, it is known that the parts habitually covered and
shaded by the mantle of the animal, are of a paler colour
than those fully exposed to the light, just as is the case with
this incrustation. When we remember that lime, either as a
phosphate or carbonate, enters into the composition of the
hard parts, such as bones and shells, of all living animals, it
is an interesting physiological fact [6] to find substances
harder than the enamel of teeth, and coloured surfaces as well
polished as those of a fresh shell, reformed through inorganic
means from dead organic matter -- mocking, also, in
shape, some of the lower vegetable productions.

We found on St. Paul's only two kinds of birds -- the
booby and the noddy. The former is a species of gannet,
and the latter a tern. Both are of a tame and stupid
disposition, and are so unaccustomed to visitors, that I could
have killed any number of them with my geological hammer.
The booby lays her eggs on the bare rock; but the tern makes
a very simple nest with seaweed. By the side of many of
these nests a small flying-fish was placed; which I suppose,
had been brought by the male bird for its partner. It was
amusing to watch how quickly a large and active crab
(Graspus), which inhabits the crevices of the rock, stole the
fish from the side of the nest, as soon as we had disturbed
the parent birds. Sir W. Symonds, one of the few persons
who have landed here, informs me that he saw the crabs
dragging even the young birds out of their nests, and devouring
them. Not a single plant, not even a lichen, grows
on this islet; yet it is inhabited by several insects and
spiders. The following list completes, I believe, the
terrestrial fauna: a fly (Olfersia) living on the booby, and
a tick which must have come here as a parasite on the birds;
a small brown moth, belonging to a genus that feeds on feathers;