422 S. E. Howorth—A Great Post- Glacial Flood. 



the freshwaters in the way supposed may be doubted." (Silliraan's 

 Journal, 3rd ser. vol. 13, p. 384). 



It seems to me most clear, in fact, that the fluviatile or lacustrine 

 theories, whatever modification of it is appealed to, and under what- 

 ever conditions, as applied to the valley terraces, breaks down at every 

 point. Where, then, are we to find an adequate explanation ? It is 

 clear that such an explanation must postulate some physical cause of 

 an abnormally potent nature, which is not in operation at present. We 

 cannot doubt that water was the means by which the materials of the 

 terraces were, in many cases, sifted and redeposited. We cannot doubt, 

 therefore, that this water must have reached to at least the level 

 of the upper terraces. These seem inevitable factors. If so, are 

 we not justified in having recourse to the same overwhelming cause 

 which we have quoted so often in these papers — a vast and sudden 

 rush of waters operating on a large scale ? Assuredly such a flood 

 would admirably explain the facts. It is perfectly consistent with 

 the valley terraces being composed, as we find them, of subaerial 

 materials, and containing no fluviatile shells, etc., and with their 

 having been subsequently rearranged and transported, "remanies," 

 as the French call it. It is consistent with these deposits being 

 found in continuous sheets in certain places, continuous too with the 

 loams covering the high plateaux, and distributed independently 

 of the drainage of the country. It explains how these deposits 

 should occur in the lateral valleys up to their very heads. It 

 explains the occurrence of the skeleton of the Ehinoceros de- 

 scribed by M. Baillon at Menchecourt with its leg a little 

 distance away, as if wrenched off by a violent blow, as we 

 described in a former paper, just as the same kind of flood 

 explains, as we have tried to show, the similar entombments in 

 Siberia and in the Loess. It explains the occurrence of mixed bands 

 with sea shells occurring with the subaerial loams and gravels we 

 are discussing, at points near the sea, as at Menchecourt. The 

 course of the great wave of waters having, no doubt, been largely 

 up the rivers, and having, therefore, not only washed the loose 

 materials up into the heads of the lateral valleys, but also mixed 

 with the surface deposits at the outlets of the main valleys products 

 of the sea with those of the land. 



It explains the presence in the terraces of the Somme of masses of 

 grey wether sandstone, several feet long, having generally their 

 edges unworn, and, as Lyell says, when spherical, owing their shape 

 to an original concretionary structure, and not to trituration in a 

 river bed. These grey wethers are accompanied by broken chalk 

 of every size from a fine powder up to fragments as large as a man's 

 head. "Many of these fragments," says J)x. Andrews, "though 

 soft enough to write with upon a blackboard, have preserved with 

 absolute perfection the sharp angles and edges which they had at 

 the time they were broken from the Cretaceous strata. It does not 

 seem possible," he adds, that " they could have been rolled a hundred 

 feet in the bed of a stream without losing their sharpness " (op. cit. 

 183). Ice has been the easy refuge for those who have needed a 



