55& Geological Society of London. 



Geological Society of London. — The opening meeting of this 

 Society took place on November 6, 1867. Warington W. Smyth, Esq., 

 M.A., F.E.S., President, in the chair. The only communication read 

 was " On the Amiens Gravel," by A. Tylor, Esq., E.L.S., F.G.S., 

 vp-hich, with the discussion which followed, occupied the entire even- 

 ing. The author referred first to the prevalent views respecting the 

 gravels of the Valley of the Somme, namely (1) that there are two 

 deposits of distinct age — the upper and the lower valley gravels ; 

 (2) that the former of these is the older ; (3) that the Valley of the 

 Somme has been excavated to the depth of forty or fifty feet since its 

 deposition ; (4) that both gravels contain bones of extinct animals 

 and implements of human manufacture, the lower gravels, however, 

 containing the greater number of species of moUusca, and the upper 

 the greater number of flint implements ; and (5) that the height 

 (70 feet) of the gravels at St. Acheul above the present level of the 

 Somme is much beyond the limit of floods, and that, therefore, they 

 could only have been deposited before the river-channel was cut 

 down to its present level. He then pointed out that the general 

 effect of these views is to refer back the remains of man found at 

 St. Acheul to an indefinite date separated from the historical period 

 by an interval during which the valley was excavated. 



In former papers Mr. Tylor stated his belief that the upper and 

 lower valley-gravels of the Somme are continuous and of the same 

 age, which he considered to be close to the historical period. In 

 this paper he stated facts, which appeared to him to demonstrate the 

 truth of his views, and described a number of sections near Amiens, 

 in which the levels were laid down from an exhaustive survey by 

 M. Guillom, Chief Engineer of the Northern Eailway of France. 



The conclusions he had thus been able to arrive at are the 

 following : — (1) 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 gravel or loess now to be seen there ; (2) that the whole of 

 the Amiens valley gravel is of one formation, of similar mineral cha- 

 racter, contains nearly similar organic remains, and belongs to a date 

 not much antecedent to the historical period ; (3) that the gravel in 

 the valley of the Somme at Amiens is partly composed of debris 

 brought down by the river Somme and by the two rivers the Celle 

 and Arve ; and partly of material from the higher grounds washed 

 in by land-floods ; (4) that the Quarternary gravels of the Somme 

 are not separated into two divisions by an escarpment of Chalk 

 parallel to the river, as has been stated; (5) that the evidence of 

 river-floods extending to a height of at least 80 feet above the pre- 

 sent level of the Somme is perfectly proved by the gradual slope and 

 continuity of the gravels deposited by them ; and (6) that many of 

 the Quarternary deposits in all countries, clearly posterior to the form- 

 ation of the valleys in which they lie, are of such great dimensions 

 and elevation that they indicate a pluvial period just as clearly as the 



