112 FLINT IMPLEMENTS IN VALLEY OF THE SOMME. chap. vn. 



not been confined simply to subsidence, but have comprised 

 oscillations in the level of the land, by which marine shells 

 of the post-pliocene pex-iod have been raised some ten feet or 

 more above the level of the sea. 



Small as is the progress hitherto made in interpreting the 

 pages of the peaty record, their importance in the Yalley of 

 the Somme is enhanced by the reflection that, whatever be 

 the number of centuries to which they relate, they belong 

 to times posterior to the ancient implement-bearing beds, 

 which we are next to consider, and are even separated from 

 them, as we shall see, by an interval far greater than that 

 which divides the earliest strata of the peat from the latest. 



Flint Implements of the Post-pliocene Period in the Valley of 

 the Somme. 



The alluvium of the Yalle}' of the Somme exhibits nothing 

 extraordinary or exceptional in its position or external 

 appearance, nor in the arrangement or composition of its 

 materials, nor in its organic remains ; in all these characters 

 it might be matched by the drift of a hundred other valleys 

 in France or England. Its claim to our peculiar attention 

 is derived from the wonderful number of flint tools, of a 

 very antique type, which, as stated in the last chapter, 

 occur in undisturbed strata, associated with the bones of 

 extinct quadru2:)eds. 



As much doubt has been cast on the question whether the 

 so-called flint hatchets have really been shaped by the hands 

 of man, it will be desirable to begin by satisfying the reader's 

 mind on that j)oint, before inviting him to study the details 

 of sections of successive beds of mud, sand, and gravel, which 

 vary considerably even in contiguous localities. 



Since the spring of 1859, I have paid three visits to 

 the Valley of the Somme, and examined all the principal 



