ms to be no more than the expressed
viscorous juice of the trees. Coal is a similar formation, but due to a
more ancient period. The mines of Pennsylvania occasionally furnish
specimens, in which the fibre of the wood is as distinctly visible as in
recently prepared charcoal. However these vast beds may have been
formed, no doubt whatever can exist in respect to their vegetable
origin.

Among animal remains found in the fossil state, shells and zoophytes are
the most abundant. They form the principal parts of rocks which often
occupy considerable districts. They are most frequent in calcareous
strata, from the transition limestones to the highest of the marles. A
remarkable fact is observed in respect to these shells, and the other
fossils which accompany them; those which are found in the oldest, or
transition formations, are more different from those that now exist,
than those in the more modern deposits. Thus the transition limestones
and slates contain terrebratulites, with encrinites, pentacrinites, and
trilobites; in those of the submedial and medial series we find
belemnites and the cornu ammonis; many of which are extinct genera, and
some of which are of families that are no longer found living on our
globe, while even where the genus is now to be met with, the species at
least has become extinct; while in the latest of the tertiary or
superior formations, we find ostracites, pectinites, buccinites,
chamites, and many other genera that are still abundant, and even types
of living species.

By far the greater part of the animals whose remains are found in the
older strata are aquatic, and the vast extents over which they are
distributed, show, that the waters must at one time have covered a very
great proportion of what is now dry land. Nor has this change been
produced by any gradual subsidence, for we find no coincidence in the
levels of those portions of the land that contain similar fossils; some
for instance are still lower than the level of the present ocean;
others, again, of similar character, rest upon the tops or sides of the
highest mountains. In Europe, the tops of the highest of the Pyrenees,
rising 11000 feet above the level of the sea, are of limestone,
containing numerous fossil remains, while Humboldt found a rock,
similarly characterized, among the Andes, at the height of 14000 feet.

The ancient philosophers, who, in other departments of physical science,
were far behind the moderns, seem in