f)00 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 3, 



This curious discovery has necessarily led to the age of the beds 

 being more closely examined and questioned. M. Elie de Beaumont has 

 recently given the weight of his high authority in favour of their com- 

 paratively modern age, — of the age, possibly, of some of the peat-beds 

 of the Valley of the Somme, or of the Swiss lake-dwellings. I cannot 

 at all agree with this view, and it is this consideration that is more 

 particularly the cause of my laying the present paper before the 

 Society. In the first place, it is assumed that at the time of the 

 formation of the beds in question the valley had its present depth and 

 shape, and that the beds at Moulin Quignon result from a secular 

 wave of translation rushing in from the sea, or from the bursting of 

 lakes or the sudden melting of the snow of mountain-chains. The 

 hill at Moulin Quignon is 105 feet above the level of the sea, or 

 87 feet above the river. I have shown elsewhere how out of the 

 question it is to invoke any river-floods of the present day ; for as the 

 Valley of the Somme, between Amiens and Abbeville, is, at a rough 

 estimate, 6000 feet broad and 100 feet deep below the level of the 

 high-level valley-gravels, with which I would connect the beds at 

 Moulin Quignon, the sectional area of the valley at that height is to 

 the sectional area of the present river at periods of flood about 

 as 600,000 to 6000. Therefore, a supply of water 100 times greater 

 than that flowing off during ordinary floods at the present day 

 would be required to produce a flood rising to the level of Moulin 

 Quignon, — an occurrence, in the present climatal conditions, perfectly 

 impossible, as it would require the accumulated rainfall, not of one 

 month or of one year, but of several years, to fill the valley with 

 water, even in a state of rest. 



The sudden melting of snow on mountain-chains, or the bursting 

 of inland lakes, is equally untenable, inasmuch as the watershed 

 separating the Somme from the Oise is only six miles broad and 

 80 feet high, so that any flood coming from the interior would 

 almost inevitably transport the debris of one basin into the other, 

 whereas not a fragment of the oolitic and old rock- debris of the 

 Valley of the Oise has passed over into the Valley of the Somme. 

 With regard to a wave coming in from the sea and throwing up or 

 sweeping down debris of gravel of older Quaternary beds and of 

 the land-surfaces upon the hill-slopes against which it rose, let us 

 see what would be the consequences of such an action. If, as the 

 eminent geologist who offers this explanation supposes, such waves 

 of translation occurred within the Celtic or Boman times, then we 

 ought to have in these high-level valley-gravels remains of Man of 

 that date, whereas no such remains have ever been found. 



Secondly, whenever this inroad of the sea took place, the retiring 

 water, in sweeping down the slopes, besides lodging the gravel on 

 the higher ground, must necessarily have carried part into the 

 lower levels ; and it should be found intercalated with the alluvial 

 and peat-beds of the valley, whereas no such intercalated beds are 

 ever found, the valley-gravels always passing under the entire mass 

 of alluvium and peat. Thirdly, the debris of the extinct Mammalia 

 in such reconstructed beds would necessarily be more or less worn, 



