270 
by M. Boucher de Perthes, it would appear that there must 
have been, at one time, lake habitations in the neighbourhood 
of Abbeville. He found considerable platforms of wood, 
with large quantities of bones, stone implements, and handles 
closely resembling those which come from the Swiss lakes. 
These weapons cannot for an instant be confounded with the 
ruder ones from the drift gravel. They are ground to a 
smooth surface and a cutting edge, while the more ancient 
ones are merely chipped, not one of the many hundreds 
already found having shown the slightest trace of grinding. 
Yet, though the former belong to the stone age, to a time so 
remote that the use of metal was apparently still unknown 
in Western Europe, they are separated from the earlier 
weapons of the upper level drift by the whole period necessary 
for the excavation of the Somme Valley to a depth of more 
than 100 feet. 
If, therefore, we get no definite date for the arrival of man 
in these countries, we can at least form a vivid idea of his 
antiquity. He must have seen the Somme running at a 
height of, in round numbers, a hundred and fifty feet above 
its present level. From finding the hatchets in the gravel up 
to a level of a hundred feet, it is probable that he dates back 
in Northern France almost, if not quite, as long as the rivers 
themselves. The face of the country must have been indeed 
unlike what it is now. Along the banks of the rivers ranged 
a savage race of hunters and fishermen, and in the forests 
wandered the mammoth, the two-horned woolly rhinoceros, 
a species of tiger, the musk ox, the reindeer, and the urus. 
Yet the geography of France cannot have been very different 
from what it is at present. The present rivers ran in their 
present directions, and the sea even then lay between the 
Somme and the Adur, though the channel was not so wide as 
it is at present. Gradually the river deepened its valley; 
ineffective, or even perhaps constructive, in autumn and 
