d now to the transportation of plants of all
sorts, that had been uprooted in the riparian forests by torrents and
rivers, to lakes of wide extent or to estuaries. Not being able to enter
in this place into the details of the various hypotheses, or to thoroughly
discuss them, we shall be content to make known a few facts that have been
recently observed, and that will throw a little light upon certain still
obscure points regarding the formation of coal.

(1) According to the first theory, if the impressions which we often find
in coal (such as the leaves of Cordaites, bark of Sigillarias and
Lepidodendrons, wood of Cordaites, Calamodendrons, etc.) are but simple
and superficial mouldings, executed by a peculiar bitumen, formerly fluid,
now solidified, and resembling in its properties no other bitumen known,
we ought not to find in the interior any trace of preservation or any
evidence of structure. Now, upon making preparations that are sufficiently
thin to be transparent, from coal apparently formed of impressions of the
leaves of Cordaites, we succeed in distinguishing (in a section
perpendicular to the limb) the cuticle and the first row of epidermic
cells, the vascular bundles that correspond to the veins and the bands of
hypodermic libers; but the loose, thin-walled cells of the mesophyllum are
not seen, because they have been crushed by pressure, and their walls
touch each other. The portions of coal that contain impressions of the
bark of Sigillaria and Lepidodendron allow the elongated, suberose tissue
characteristic of such bark to be still more clearly seen.

Were we to admit that the bitumen was sufficiently fluid to penetrate all
parts of the vegetable debris, as silica and carbonates of lime and iron
have done in so many cases, we should meet with one great difficulty. In
fact, the number of fragments of coal _isolated_ in schists and sandstone
is very large, and _without any communication_ with veins of coal or of
bitumen that could have penetrated the vegetable. We cannot, then, for an
instant admit such a hypothesis. Neither can we admit that the penetration
of the plants by bitumen was effected at a certain distance, and that they
have been transported, after the operation, to the places where we now
find them, since it is not rare to find at Commentry trunks of
Calamodendrons, Anthropitus, and ferns which are still provided with roots
from 15 to 30 feet in length, and the carbonized wood of which surro