CHAP. IX. FLINT TOOLS NEAK BEDFOKD. 165 



valley was scooped out. It is a portion of the great marine 

 glacial drift of the midland counties of England, and contains 

 blocks, some of large size, not only of the oolite of the neigh 

 bourhood, but of chalk and other rocks transported from still 

 greater distances, such as syenite, basalt, quartz, and new red 

 sandstone. These erratic blocks of foreign origin are often 

 polished and striated, having undergone what is called 

 glaciation, of which more will be said by and by. Blocks 

 of the same mineral character, embedded at Biddenham 

 in the gravel No. 3, have lost all signs of this striation by 

 the friction to which they were subjected in the old river-bed. 

 The great width of the valley of the Ouse, which is some 

 times two miles, has not been expressed in the diagram. It 

 may have been shaped out by the joint action of the river and 

 the tides when this part of England was emerging from the 

 waters of the glacial sea, the boulder clay being first cut 

 through, and then an equal thickness of underlying oolite. 

 After this denudation, which may have accompanied the 

 emergence of the land, the country was inhabited by the 

 primitive people who fashioned the flint tools. The 

 old river, aided perhaps by the continued upheaval of the 

 whole country, or by oscillations in its level, went on 

 widening and deepening the valley, often shifting its channel, 

 until at length a broad area was covered by a succession 

 of the earliest and latest deposits, which may have cor 

 responded in age to the higher and lower gravels of the valley 

 of the Somme, already described, p. 130. Mr. Prestwich 

 has hinted that perhaps the drift of Biddenham, which is 

 thirty feet above the present level of the Ouse, and contains 

 bones of Elephas primigenius, and the shells above alluded 

 to, may be a higher level alluvium ; and the gravel on which, 

 the town of Bedford is built, which is at an inferior level 

 relatively to the Ouse, may be a lower deposit and con 

 sequently newer. But we have scarcely as yet sufficient data 



