in museums
specimens of this family, now so rare, all but extinct. And yet
fifty or a hundred different forms of the same type swarmed in the
ancient seas: whole masses of limestone are made up of little else
but the fragments of such animals.

But we have not landed yet on the dry part of the reef. Let us make
for it, taking care meanwhile that we do not get our feet cut by the
coral, or stung as by nettles by the coral insects. We shall see
that the dry land is made up entirely of coral, ground and broken by
the waves, and hurled inland by the storm, sometimes in huge
boulders, mostly as fine mud; and that, under the influence of the
sun and of the rain, which filters through it, charged with lime from
the rotting coral, the whole is setting, as cement sets, into rock.
And what is this? A long bank of stone standing up as a low cliff,
ten or twelve feet above high-water mark. It is full of fragments of
shell, of fragments of coral, of all sorts of animal remains; and the
lower part of it is quite hard rock. Moreover, it is bedded in
regular layers, just such as you see in a quarry. But how did it get
there? It must have been formed at the sea-level, some of it,
indeed, under the sea; for here are great masses of madrepore and
limestone corals imbedded just as they grew. What lifted it up?
Your companions, if you have any who know the island, have no
difficulty in telling you. It was hove up, they say, in the
earthquake in such and such a year; and they will tell you, perhaps,
that if you will go on shore to the main island which rises inside
the reef, you may see dead coral beds just like these lying on the
old rocks, and sloping up along the flanks of the mountains to
several hundred feet above the sea. I have seen such many a time.

Thus you find the coral being converted gradually into a limestone
rock, either fine and homogeneous, composed of coral grown into pulp,
or filled with corals and shells, or with angular fragments of older
coral rock. Did you never see that last? No? Yes, you have a
hundred times. You have but to look at the marbles commonly used
about these islands, with angular fragments imbedded in the mass, and
here and there a shell, the whole cemented together by water holding
in solution carbonate of lime, and there see the very same phenomenon
perpetuated to this day.

Thus, I think, we have got first from the known to the unknown; from
a t