oft in spite of his hard
shell, he lines them with a quantity of cocoa-nut fibre, picked out clean
and fine, just as if he was going to make cocoa-nut matting of it. And
being also a clean crab, as I hope you are a clean little boy, he goes
down to the sea every night to have his bath and moisten his gills, and
so lives happy all his days, and gets so fat in his old age that he
carries about his body nearly a quart of pure oil.

That is the history of the cocoa-nut crab. And if any one tells me that
that crab acts only on what is called "instinct"; and does not think and
reason, just as you and I think and reason, though of course not in words
as you and I do: then I shall be inclined to say that that person does
not think nor reason either.

Then were there many coral-reefs in Britain in old times?

Yes, many and many, again and again; some whole ages older than this, a
bit of which you see, and some again whole ages newer. But look: then
judge for yourself. Look at this geological map. Wherever you see a bit
of blue, which is the mark for limestone, you may say, "There is a bit of
old coral-reef rising up to the surface." But because I will not puzzle
your little head with too many things at once, you shall look at one set
of coral-reefs which are far newer than this bit of Dudley limestone, and
which are the largest, I suppose, that ever were in this country; or, at
least, there is more of them left than of any others.

Look first at Ireland. You see that almost all the middle of Ireland is
coloured blue. It is one great sheet of old coral-reef and coral-mud,
which is now called the carboniferous limestone. You see red and purple
patches rising out of it, like islands--and islands I suppose they were,
of hard and ancient rock, standing up in the middle of the coral sea.

But look again, and you will see that along the west coast of Ireland,
except in a very few places, like Galway Bay, the blue limestone does not
come down to the sea; the shore is coloured purple and brown, and those
colours mark the ancient rocks and high mountains of Mayo and Galway and
Kerry, which stand as barriers to keep the raging surf of the Atlantic
from bursting inland and beating away, as it surely would in course of
time, the low flat limestone plain of the middle of Ireland. But the
same coral-reefs once stretched out far to the westward into the Atlantic
Ocean; and you may see the proof upon that map. For in the western ba