230 FOSSIL MEN. 



subject. To give such a state of things as that im- 

 plied in these high-level gravels, we must suppose 

 that the Somme valley was flat and filled up with 

 detritus, presenting an alluvial plain over which the 

 river, at times of flood, could spread itself with great 

 ease, while the climate must have been sufficiently 

 severe to allow ice to float in spring freshets large 

 blocks of stone. This implies a lower level of the 

 country than at present, and probably a very recent 

 elevation out of the sea, followed by a condition of 

 much greater rainfall and more severe floods. Now, at 

 the mouth of the Somme there are beds of peat, the 

 bottom of which is below the level of the sea ; conse- 

 quently this modern peat began to be formed at a 

 time when the land was higher than it is at present ; 

 and the submerged forests with remains of man and 

 modern animals, at several points along the coasts of 

 France and England, give us the same indication. 

 First, then, we learn from the peat that immediately 

 before the historical period the Somme valley was 

 higher than now, and the circumstances more favour- 

 able than at present to its rapid cutting. But the 

 gravels must have been deposited before this in a 

 previous time of lower level. Now, that man existed 

 at this time of lower level, we have evidence elsewhere. 

 Nilsson has described certain skulls found in beds 

 holding marine shells on the coast of Sweden at an 

 elevation of 100 feet above the sea, and infers that the 

 men to whom they belonged were drowned when the 

 sea was at that height on the land. It has long been 



