greatest service to the human race, even to the extent of favouring
the progress of its civilization.

The animal remains of this era are not numerous, in comparison with
those which go before, or those which come after. The mountain
limestone, indeed, deposited at the commencement of it, abounds
unusually in polypiaria and crinoidea; but when we ascend to the
coal-beds themselves, the case is altered, and these marine remains
altogether disappear. We have then only a limited variety of
conchifers and shell mollusks, with fragments of a few species of
fishes, and these are rarely or never found in the coal seams, but in
the shales alternating with them. Some of the fishes are of a
sauroid character, that is, partake of the nature of the lizard, a
genus of the reptilia, a land class of animals, so that we may be
said here to have the first approach to a kind of animals calculated
to breathe the atmosphere. Such is the Megalichthys Hibbertii, found
by Dr. Hibbert Ware, in a limestone bed of fresh-water origin,
underneath the coal at Burdiehouse, near Edinburgh. Others of the
same kind have been found in the coal measures in Yorkshire, and in
the low coal shales at Manchester. This is no more than might be
expected, as collections of fresh water now existed, and it is
presumable that they would be peopled. The chief other fishes of the
coal era are named palaeothrissum, palaeoniscus, diperdus.

Coal strata are nearly confined to the group termed the carboniferous
formation. Thin beds are not unknown afterwards, but they occur only
as a rare exception. It is therefore thought that the most important
of the conditions which allowed of so abundant a terrestrial
vegetation, had ceased about the time when this formation was closed.
The high temperature was not one of the conditions which terminated,