The human bones discovered are yet more convincing
testimony. Excavations have yielded some which may date from the very
earliest period of the existence of man upon the earth. They have been
found in caves and in the river drift, beneath the mounds of America
and the megalithic monuments of Europe, in the ice-clad districts of
Scandinavia and of Iceland, and in the burning deserts of Africa,
but not one of them owes its existence to men of a type different
from those of historic times or of our own day.[48] MM. Quatrefages
and Hamy in their magnificent work "Crania Ethnica," have been
able to distinguish prehistoric races and indicate the area they
occupied. These races are still represented, and their descendants
of to-day retain the characteristics of their ancestors.

One final conclusion is no less interesting. These absolutely
countless flints, these monuments of imposing size, these stones
of immense weight often brought from afar, these marvellous mounds
and tumuli, bear witness to the presence of a population which was
already considerable at the time of which we are endeavoring to make
out the traces. A long series of centuries must have been needed
for a people to increase to such an extent as to have spread over
entire continents. And time was not wanting. Whatever antiquity may
be attributed to the human race, whatever the initial date to which
its first appearance may be relegated, this antiquity is but slight,
this date is but modern, if we compare it with the truly incalculable
ages of which geology reveals the existence. At every turn we are
arrested by the immensity of time, the immensity of space, and yet
our knowledge is still confined to the mere outer rind of the earth,
and science cannot as yet even guess at the secrets hidden beneath
that rind.