You find over great tracts of East Scotland, Lancashire, Norfolk,
etc., pure loose sand just beneath the surface, which looks as if it
was blown sand from a beach. Is it not reasonable to suppose that it
is? You find rising out of many lowlands, crags which look exactly
like old sea-cliffs eaten by the waves, from the base of which the
waters have gone back. Why should not those crags be old sea-cliffs?
Why should we not, following our rule of explaining the unknown by
the known, assume that such they are till someone gives us a sound
proof that they are not; and say--These great plains of England and
Scotland were probably once covered by a shallow sea, and their soils
made as the soil of any tide-flat is being made now?

But you may say, and most reasonably "The tide-flats are just at the
sea-level. The whole of the lowland is many feet above the sea; it
must therefore have been raised out of the sea, according to your
theory: and what proofs have you of that?"

Well, that is a question both grand and deep, on which I shall not
enter yet; but meanwhile, to satisfy you that I wish to play fair
with you, I ask you to believe nothing but what you can prove for
yourselves. Let me ask you this: suppose that you had proof
positive that I had fallen into the river in the morning; would not
your meeting me in the evening be also proof positive that somehow or
other I had in the course of the day got out of the river? I think
you will accept that logic as sound.

Now if I can give you proof positive, proof which you can see with
your own eyes, and handle with your own hands, and alas! often feel
but too keenly with your own feet, that the whole of the lowlands
were once beneath the sea; then will it not be certain that, somehow