FLOWER FLINT IMPLEMENTS. 55 



masses of gravel which now are seen resting on their banks, or for 

 the partial denudation of the adjacent hills. The Little Ouse is 

 formed by the confluence of three small streams, which take their 

 rise at a short distance from Thetford, and join each other just above 

 the gravel-terrace in question. It appears, from the map lately- 

 published under the superintendence of this Society, that during the 

 entire course of this river, for about forty miles, from its source to the 

 outfall at Lynn, the fall is but fifteen feet — a little over four inches 

 in the mile. At a short distance above the gravel-terrace the river 

 is about three feet deep and fifty wide ; while in order to fill the 

 valley only to the height of the gravel a stream of about sixtyfold 

 greater volume would be required, and this would very far transcend 

 the capacity of the watershed. 



In the paper before referred to, Mr. Prestvdch observes that it 

 would be impossible for the present rivers, even during their greatest 

 floods, to attain a height at all approaching to the high-level gravels, 

 and suggests that from the melting of the snow, independently of 

 any larger rainfall, the floods must formerly have been far greater, 

 and have given to the river a torrential character, and that thus the 

 ancient channels have been deepened. 



But, as applied to Thetford, the phenomena in question can hardly 

 be accounted for on this supposition. Snows do not give forth tor- 

 rents of water sufficient in volume and force for the transport of 

 such deposits as are here exhibited, unless in regions (at least to 

 some extent) mountainous ; and it is impossible to find any moun- 

 tainous, or indeed any high, land in the narrow watersheds of the 

 Waveney and the Oiise ; and to affirm that some such district once 

 existed, which has now disappeared, leaving no traces of its exist- 

 ence, would be a gratuitous assumption, remitting us to the region of 

 pure conjecture. 



In conclusion, I would venture to suggest that this and kindred 

 deposits may reasonably be accounted for without having recourse to 

 the river theory, which is attended with so many difficulties. Here 

 not only has aU the Boulder- clay on one side of the valley, and to 

 the extent of three-quarters of a mile in breadth on the other, been 

 carried away, together with large masses of the Chalk on which it 

 once reposed, but vast masses of the flint-gravel which, doubtless, 

 once covered the adjacent hills (and of which extensive traces still 

 remain) have also been removed. It is clearly impossible to ascribe 

 these results to the little gentle stream which finds its way in the 

 valley below, or to any other flowing in the same course; and if the 

 formation of the valley, and the partial denudation of the hills which 

 bound it, must be explained in some other way than by river- 

 action, why should not the contents of the valley come into the same 

 category, especially as they bear unmistakeable marks of violent 

 transport. The same law that induces water to find the lowest 

 level operates upon aU water-borne materials ; and if the excavation 

 of these wide valleys, and the partial removal of the drift from the 

 adjoining hills, may reasonably be attributed to the passage of some 

 great body of water over the surface of the land, the sands and gravel 



