the still water; and say to yourself: Perhaps the sands which cover
so many inland tracts were dropped by water, very near the shore of a
lake or sea, and by rapid currents. Perhaps, again, the brick clays,
which are often mingled with these sands, were dropped, like the mud
in the pond, in deeper water farther from the shore, and certainly in
stilt water. But more. Suppose once more, then, that looking and
watching a pond being cleared out, under the lowest layer of mud, you
found--as you would find in any of those magnificent reservoirs so
common in the Lancashire hills--a layer of vegetable soil, with grass
and brushwood rooted in it. What would you say but: The pond has
not been always full. It has at some time or other been dry enough
to let a whole copse grow up inside it?

And if you found--as you will actually find along some English
shores--under the sand hills, perhaps a bed of earth with shells and
bones; under that a bed of peat; under that one of blue silt; under
that a buried forest, with the trees upright and rooted; under that
another layer of blue silt full of roots and vegetable fibre; perhaps
under that again another old land surface with trees again growing in
it; and under all the main bottom clay of the district--what would
common sense tell you? I leave you to discover for yourselves. It
certainly would not tell you that those trees were thrust in there by
a violent convulsion, or that all those layers were deposited there
in a few days, or even a few years; and you might safely indulge in
speculations about the antiquity of the aestuary, and the changes
which it has undergone, with which I will not frighten you at
present.

It will be fair reasoning to argue thus. You may not be always right
in your conclusion, but still you will be trying fairly to explain