104 PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Fifthly, that the height of 70 feet, at which fossiliferous gravels now 

 stand above the level of the Somme, is much beyond the limit of 

 floods, and therefore that these gravels could only have been depo- 

 sited at St. Acheul before the river-channel was cut down to its pre- 

 sent level. 



The general effect of these assertions was to refer the remains of 

 man found in St. Acheul back to an indefinite date, separated from 

 the historical period by an interval during which valleys were ex- 

 cavated or deepened 40 or 50 feet. 



In a paper read before this Society in April 1866*, I suggested 

 that there was evidence of very Kttle weathering or atmospheric 

 action since the date of the drift containing human remains, and that 

 the age of these deposits was close to the Historical period, — also 

 that the upper and lower valley-gravels in the Somme were con- 

 tinuous and of one period. 



I afterwards read, in June 1866, a statement of what I believed to 

 be the correct interpretation of the Amiens and Abbeville sections, 

 reasserting the continuity of the gravel-deposits on gradual slopes 

 from the higher to the lower levels in the valley, except in rare cases 

 or isolated spots, where the continuity was interrupted or prevented 

 by some upstanding piece of the original rock out of which the valley 

 had been cut, in which case the gravel wraps round the base of the 

 upstanding knoll of chalk. I quoted the section at Montiers as one 

 that shows a direct sequence of gravel from above the railway to the 

 Somme, notwithstanding the version of that locality published by 

 Mr. Prestwich, in which chalk is represented in a position where I 

 could only find gravel. 



At the same time attention was drawn by me to the probability 

 of the brick-earth terrace sloping down to the Lea Marshes at Clap- 

 ton being of the same age as the similarly formed Loess terrace 

 sloping down to the Somme at Amiens. I also asserted that there 

 was good evidence in the direction and gradient of the terrace, in the 

 configuration of the gravel and brick-earth and of the London-clay 

 surface at Clapton, of the water having occupied the whole valley of 

 the Lea at the time of the formation of this Clapton terrace, and 

 also of the water of the river Lea or other rivers having reached very 

 much higher levels in the vicinity at that period, while the Stoke- 

 Newington and Highbury gravels and brick-earth were being depo- 

 sited. 



I still hold these opinions, and am prepared to demonstrate 

 their truth ; and I ask the attention of the Society to a restatement 

 of the exact geological facts to be seen in the Somme valley, and to 

 evidence quite independent of that which has been previously sub- 

 mitted to the Society, although to a certain extent going over the 

 same ground. 



The conclusions that I arrive at are extremely dissimilar to those 

 of Mr. Prestwich and Sir C. Lyell, and are as follows : — 



First, that" the surface of the chalk in the valley of the Somme 

 had assumed its present form prior to the deposition of any of the 

 * Quart. Journ. Greol. Soc. toI. xxii. p. 463. 



