vegetation still bespeaks a climate considerably more genial, mild, and
equable than that of modern England.

It was in this basking world of the chalk and the Eocene that the great
mammalian fauna first took its rise; it was in this easy world of
fruits and sunshine that the primitive ancestors of man first began to
work upwards toward the distinctively human level of the palæolithic
period.

But then, in the mid-career of that third day of the geological drama,
came a frost--a nipping-frost; and slowly but surely the whole arctic
and antarctic worlds were chilled and cramped, degree after degree, by
the gradual on-coming of the Great Ice Age. I am not going to deal here
with either the causes or the extent of that colossal cataclysm; I
shall take all those for granted at present: what we are concerned with
now are the results it left behind--the changes which it wrought on
fauna and flora and on human society. Especially is it of importance in
this connection to point out that the Glacial epoch is not yet entirely
finished--if, indeed, it is ever destined to be finished. We are living
still on the fringe of the Ice Age, in a cold and cheerless era, the
legacy of the accumulated glaciers of the northern and southern
snow-fields.

If once that ice were melted off--ah, well, there is much virtue in an
_if_. Still, Mr. Alfred Russel Wallace seems to suggest somewhere that
the sun is gradually making inroads even now on those great
glacier-sheets of the northern cap, just as we know he is doing on the
smaller glacier-sheets of Switzerland (most of which are receding), and
that in time perhaps (say in a hundred thousand years or so) warm ocean
currents may once more penetrate to the very poles themselves. That,