probable to you. Its certainty has been proved by many different
men, labouring in many different parts of England, and of the
Continent also, and then comparing their discoveries together;
often, of course, making mistakes; but each working on patiently,
and correcting their early mistakes by fresh facts, till they have
at last got hold of the true key to the mystery, and are as certain
of the existence of the great island of the Weald, and its gradual
destruction by the waves and currents of an ancient sea, as if they
had seen it with their bodily eyes. You must take all this, of
course, as truth from me to-night; but you may go and examine for
yourselves; and see how far your own common sense and observations
agree with those of learned geologists.

The history of this great Wealden island to the south-east of us is
obscure enough; but a few general facts, which bear upon our gravel-
pit, I can give you.

I must begin, however, ages before the Wealden island existed; when
the chalk of which its mass was composed was at the bottom of a deep
ocean.

We know now what chalk is, and how it was made. We know that it was
deposited as white lime mud, at a vast sea-depth, seemingly
undisturbed by winds or currents. We know that not only the flint,
but the chalk itself, is made up of shells; the shell of little
microscopic animalcules smaller than a needle's point, in millions
of millions, some whole, some broken, some in powder, which lived,
and died, and decayed for ages in the great chalk sea.

We know this, I say. We had suspected it long ago, and become more