dergrowth
beneath was composed, in large proportion, of creeping plants of the
gourd and melon order. From the middle or Miocene flora of the Tertiary
division,--of which we seem to possess in Britain only the small but
interesting fragment detected by his Grace the Duke of Argyll among the
trap-beds of Mull,--most of the more exotic forms seem to have been
excluded. The palms, however, still survive in no fewer than thirty-one
different species, and we find in great abundance, in the place of the
other exotics, remains of the plane and buckthorn families,--part of a
group of plants that in their general aspect, as shown in the Tertiary
deposits of the Continent, not a little resembled the vegetation of the
United States at the present day. The nearer we approach to existing
times, the more familiar in form and outline do the herbs and trees
become. We detect, as has been shown, at least one existing _order_ in
the ferns of the Coal Measures; we detect at least existing _genera_
among the Coniferae, Equisetaceae, and Cycadaceae of the Oolite; the
acacias, gourds, and laurels of the Eocene flora, and the planes,
willows, and buckthorns of the Miocene, though we fail to identify their
species with aught that now lives, still more strongly remind us of the
recent productions of our forests or conservatories; and, on entering,
in our downward course, the Pleistocene period, we at length find
ourselves among familiar _species_. On old terrestrial surfaces, that
date before the times of the glacial period, and underlie the boulder
clay, the remains of forests of oak, birch, hazel, and fir have been
detected,--all of the familiar species indigenous to the country, and
which still flourish in our native woods. And it was held by the late
Professor Edward Forbes, that the most ancient of his five existing
British floras,--that which occurs in the south-west of Ireland, and
corresponds with the flora of the northwest of Spain and the
Pyrenees,--had been introduced into the country as early, perhaps, as
the times of the Miocene. Be this, however, as it may, there can rest no
doubt on the great antiquity of the prevailing trees of our indigenous
forests.

The oak, the birch, the hazel, the Scotch fir, all lived, I repeat, in
what is now Britain, ere the last great depression of the land. The
gigantic northern elephant and rhinoceros, extinct for untold ages,
forced their way through their tangled branches; and the British tiger
an