ion. Ere passing to the
luxuriant carboniferous flora, I shall make but one other remark. The
existing plants whence we derive our analogies in dealing with the
vegetation of this early period, contribute but little, if at all, to
the support of animal life. The ferns and their allies remain untouched
by the grazing animals. Our native club mosses, though once used in
medicine, are positively deleterious; the horse tails, though harmless,
so abound in silex, which wraps them round with a cuticle of stone, that
they are rarely cropped by cattle; while the thickets of fern which
cover our hill-sides, and seem so temptingly rich and green in their
season, scarce support the existence of a single creature, and remain
untouched in stem and leaf, from their first appearance in spring, until
they droop and wither under the frosts of early winter. Even the insects
that infest the herbaria of the botanist almost never injure his ferns.
Nor are our resin-producing conifers, though they nourish a few beetles,
favorites with the herbivorous tribes in a much greater degree. Judging
from all we yet know, the earliest terrestrial flora may have covered
the dry land with its mantle of cheerful green, and served its general
purposes, chemical and others, in the well-balanced economy of nature;
but the herb-eating animals would have fared but ill even where it
throve most luxuriantly; and it seems to harmonize with the fact of its
non-edible character, that up to the present time we know not that a
single herbivorous animal lived among its shades. From all that
appears, it may be inferred that it had not to serve the purposes of the
floras of the passing time, in which, according to the poet,

"The world's bread depends on the shooting of a seed."

[Illustration: Fig. 13.

FERN? of Lower Old Red Sandstone. Orkney.

(Nat. Size.)]

The flora of the Coal Measures was the richest and most luxuriant, in at
least individual productions, with which the fossil botanist has formed
any acquaintance. Never before or since did our planet bear so rank a
vegetation as that of which the numerous coal seams and inflammable
shales of the carboniferous period form but a portion of the
remains,--the portion spared, in the first instance, by dissipation and
decay, and in the second by the denuding agencies. Almost all our
coal,--the stored up fuel of a world,--forms but a comparatively small
part of the produce of this wonderful flora. Amid much that