these semi-metaphysical phrases.

It has seemed advisable to take this further glance at the general
principles and current theories of evolution before we extend our own
procedure into the Tertiary Era. The highest types of animals and plants
are now about to appear on the stage of the earth; the theatre itself is
about to take on a modern complexion. The Middle Ages are over; the new
age is breaking upon the planet. We will, as before, first survey the
Tertiary Era as a whole, with the momentous changes it introduces, and
then examine, in separate chapters, the more important phases of its
life.

It opens, like the preceding and the following era, with "the area
of land large and its relief pronounced." This is the outcome of the
Cretaceous revolution. Southern Europe and Southern Asia have risen, and
shaken the last masses of the Chalk ocean from their faces; the whole
western fringe of America has similarly emerged from the sea that had
flooded it. In many parts, as in England (at that time a part of the
Continent), there is so great a gap between the latest Cretaceous
and the earliest Tertiary strata that these newly elevated lands must
evidently have stood out of the waters for a prolonged period. On their
cooler plains the tragedy of the extinction of the great reptiles comes
to an end. The cyeads and ginkgoes have shrunk into thin survivors of
the luxuriant Mesozoic groves. The oak and beech and other deciduous
trees spread slowly over the successive lands, amid the glare and
thunder of the numerous volcanoes which the disturbance of the crust has
brought into play. New forms of birds fly from tree to tree, or linger
by the waters; and strange patriarchal types of mammals begin to move
among the bones of the stricken reptiles.

But the seas and the rains and rivers are acting with renewed vigour
on the elevated lands, and the Eocene period closes in a fresh age of
levelling. Let us put the work of a million years or so in a sentence.
The southern sea, which has been confined almost to the limits of our
Mediterranean by the Cretaceous upheaval, gradually enlarges once more.
It floods the north-west of Africa almost as far as the equator; it
covers most of Italy, Turkey, Austria, and Southern Russia; it spreads
over Asia Minor, Persia, and Southern Asia, until it joins the Pacific;
and it sends a long arm across the Franco-British region, and up the
great valley which is now the German Ocean.

From earlier cha