explain. These facts, for example, do not permit us to suppose that
coal is an accumulation of peaty matter, as some have held.

Again, the late Professor Quekett was one of the first observers
who gave a correct description of what I have termed the "saccular"
structure of coal; and, rightly perceiving that this structure was
something quite different from that of any known plant, he imagined
that it proceeded from some extinct vegetable organism which was
peculiarly abundant amongst the coal-forming plants. But this
explanation is at once shown to be untenable when the smaller and the
larger sacs are proved to be spores or sporangia.

Some, once more, have imagined that coal was of submarine origin; and
though the notion is amply and easily refuted by other considerations,
it may be worth while to remark, that it is impossible to comprehend
how a mass of light and resinous spores should have reached the bottom
of the sea, or should have stopped in that position if they had got
there.

At the same time, it is proper to remark that I do not presume to
suggest that all coal must needs have the same structure; or that
there may not be coals in which the proportions of wood and spores, or
spore-cases, are very different from those which I have examined. All
I repeat is, that none of the coals which have come under my notice
have enabled me to observe such a difference. But, according to
Principal Dawson, who has so sedulously examined the fossil remains of
plants in North America, it is otherwise with the vast accumulations
of coal in that country.

"The true coal," says Dr. Dawson, "consists principally of