nd, furthermore, Mr. Wallace and
M. Pouchet have recently treated of ethnological questions from this
point of view. Let me, in conclusion, add my own contribution to the
same store.

I assume Man to have arisen in the manner which I have discussed
elsewhere, and probably, though by no means necessarily, in one
locality. Whether he arose singly, or a number of examples appeared
contemporaneously, is also an open question for the believer in the
production of species by the gradual modification of pre-existing
ones. At what epoch of the world's history this took place, again, we
have no evidence whatever. It may have been in the older tertiary,
or earlier, but what is most important to remember is, that the
discoveries of late years have proved that man inhabited Western
Europe, at any rate, before the occurrence of those great physical
changes which have given Europe its present aspect. And as the same
evidence shows that man was the contemporary of animals which are now
extinct, it is not too much to assume that his existence dates back
at least as far as that of our present Fauna and Flora, or before the
epoch of the drift.

But if this be true, it is somewhat startling to reflect upon the
prodigious changes which have taken place in the physical geography of
this planet since man has been an occupant of it.

During that period the greater part of the British islands, of Central
Europe, of Northern Asia, have been submerged beneath the sea and
raised up again. So has the great desert of Sahara, which occupies the
major part of Northern Africa. The Caspian and the Aral seas have been
one, and their united waters have probably communicated with both the
Arctic and the Mediterranean oceans. The greater part of North America
has been under water, and has emerged. It is highly probable that
a large part of the Malayan Archipelago has sunk, and its primitive
continuity with Asia has been destroyed. Over the great Polynesian
area subsidence has taken place to the extent of many thousands of
feet--subsidence of so vast a character, in fact, that if a continent
like Asia had once occupied the area of the Pacific, the peaks of its
mountains would now show not more numerous than the islands of the
Polynesian Archipelago.

What lands may have been thickly populated for untold ages, and
subsequently have disappeared and left no sign above the waters, it
is of course impossible for us to say; but unless we are to make the
who