will he so used in these pages.

The only races of men that we could expect to find in Europe
during the Glacial Age would be Paleolithic tribes, and it is
equally manifest that we must find traces of them in beds of
this age, or in association with animals that are characteristic
of this age, or else we can not assert the existence of man at
this time. The valley of the river Somme, in Northern France,
has become classical ground to the student of Archaeology, since
it was there that such investigations as we have just mentioned
were first and most abundantly made. It is now well known that
the surface features of a country--that is, its hills and dales,
its uplands and lowlands--are mainly due to the erosive power of
running water. Our rivers have dug for themselves broad valleys,
undermined and carried away hills, and in general carved the
surface of a country, until the present appearance is the
result. It must be confessed that when we perceive the slow
apparent change from year to year, and from that attempt to
estimate the time required to produce the effects we see before
us, we are apt to shrink from the lapse of time demanded for its
accomplishment. Let us not forget that "Time is long," and that
causes, however trifling, work stupendous results in the course
of ages.


Picture of Paleolithic Flints.--------


But a river which is thus digging down its channel in one place,
deposits the materials so dug away at other and lower levels, as