layers were found with their wedges all pointing in one direction, we
should be able to judge that the currents were all from one direction,
and that, therefore, they were formed by a single river. But this is just
what we do not find, for instead of it the direction of the wedge-shaped
strata varies in almost every layer, and the current-bedding has been
brought about by currents travelling in every direction. Such diverse
current-bedding could only result from the fact that the spot where the
sand was laid down was subject to currents from every direction, and the
inference is that it was well within the sphere of influence of numerous
streams and rivers, which flowed from every direction. The only condition
of things which would explain this is that the sandstone was originally
formed in a closed sea or large lake, into which numerous rivers flowing
from every direction poured their contents.

Now, in the sandstones, the remains of numerous plants have been found,
but they do not present the perfect appearance that they do when found in
the shales; in fact they appear to have suffered a certain amount of
damage through having drifted some distance. This, together with the fact
that sandstones are not formed far out at sea, justify the safe
conclusion that the land could not have been far off. Wherever the
current-bedding shows itself in this manner we may be sure we are
examining a spot from which the land in every direction could not have
been at a very great distance, and also that, since the heavy materials
of which sandstone is composed could only be transported by being
impelled along by currents at the bed of the sea, and that in deep water
such currents could not exist, therefore we may safely decide that the
sea into which the rivers fell was a comparatively shallow one.

Although the present coal-fields of England are divided from one another
by patches of other beds, it is probable that some of them were formerly