away from the land. It
was seen, too, that each successive deposition of sand formed a
wedge-shaped layer, with the point of the wedge pointing away from the
source of origin of the sediment, and therefore of the current which
conveyed the sediment. Therefore, if in the coal-measure sandstones the
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
connected with others, and a very wide sheet of coal on each occasion was
laid down. The question arises as to what was the extent of the inland
sea or lake, and did it include the area covered by the co