of the sea. This consisted principally
of pines. This shows that probably all Northern Europe was covered
with somber forests of pine. In the same section he found, buried under
volcanic ash, a vegetation consisting mostly of deciduous trees--maples,
alders, poplars, willows, elms, and ashes. As this was growing at the
height Of about twenty-three hundred feet in Cantal France, it probably
represents the vegetation of Britain and Northern Germany. Finally, the
vegetation of Central and Southern France, as well as Northern Italy,
was intermediate in character between the luxuriant evergreen forests
of the Miocene Age and that now growing there. The tropical character of
the vegetation was evidently passing away. The climate over a large part
of Europe was now temperate, though probably warmer than at present.<55>

In the Mammalia we have to notice the disappearance of some species, and
the arrival and spread of some others. The apes living as far north as
Germany in the Miocene Age were restricted to Southern France and Italy
in the Pliocene, and, at its close, vanished altogether from Europe.
The first living species of mammals is found in the remains of the
hippopotamus that frequented the rivers of Pliocene times. The mastodon
of Miocene times was still to be seen, but along with it was a species
of true elephants. The hipparion survived into this epoch, but the horse
also makes its appearance. Great quantities of deer roamed over the
land; and, as might be expected where they were so abundant, the
carnivorous animals allied to the bears and wolves, panthers, linxes,
and tigers, were also to be found. "At night," says Mr. Dawkins, "the
Pliocene forests of Central France echoed with the weird laughter of the
hyena."

The gradual lowering of the climate is also shown by the remains of the
mollusks deposited in beds of marine or sea formation during different
eras of this age. It is found that the earlier the bed, the more
southern mollusks are found in it. This shows us that, all through the
Pliocene Age, the waters of the seas surrounding England were gradually
growing cooler, thus compelling the retreat of those mollusks fitted
only for a warm climate, and allowing a gradual increase in those
species fitted for cold or northern latitudes. We also find, in deposits
made near the close of Pliocene times, numbers of stone which show
all evidence of having been borne thither by means of ice. So we may
conclude that raft