286 



THE SOMME VALLEY. 





-SiL 

 *>* 



c 



Fig. 139 gives a section across the 

 valley of the Somme at Abbeville, taken 

 from Mr. Prestwich's first paper.* We 

 should find almost the same arrangement 

 and position of the different beds, not 

 only at St. Acheul, but elsewhere along 

 the valley of the Somme, wherever the 

 higher beds of gravel have not been 

 removed by subsequent action of the 

 river. Even at St. Valery, at the pre- 

 sent mouth of the river, I found a bed 

 of gravel at a considerable height above 

 the level of the sea. This would seem 

 to show that at the period of these high 

 level gravels, the English Channel was 

 narrower than it is at present, as indeed 

 we know to have been the case even in 

 historical times. So early as 1605 our 

 countryman Verstegan pointed out that 

 the waves and tides were eating away 

 our coasts. Sir C. Lyellf gives much 

 information on this subject, and it ap- 

 pears that even so lately as the reign of 

 Queen Elizabeth, the town of Brighton 

 was situated on the site now occupied 

 ^ by the Chain Pier. 



| Mr. Prestwich has pointed out J that 

 I a section, similar to that of the Somme, 

 <k is presented by the Lark, Waveney, 

 1 Ouse, etc., while it is well shown also 

 ^ along the banks of the Seine. Probably, 

 indeed, it holds good of most of our 



* Phil. Trans. 1860. t See Principles of Geology, p. 315. 



J Phil. Trans. 1864. 



