64 Royal Society : — 



admit of explanation, except those of a flat ovoid shape, common at 

 Abbeville, which are unlike any instrument in use amongst any exist- 

 ing uncivilized tribes. 



Notwithstanding the probable severity of the climate, it was one by 

 no means unsuited to the existence of man, whilst the character of 

 the contemporaneous animal life cf the period was perfectly fitted for 

 his support and sustenance. 



A difficulty has been raised because hitherto no human bones 

 have been found in these gravels ; but when it is considered how 

 scanty is the population in northern latitudes, and how dispropor- 

 tionately numerous are the great herds of Deer, Oxen, and other 

 animals (fossil remains of which are yet comparatively rare), this 

 fact, taken in conjunction with the foresight of man, indicates 

 how small are the chances of finding his remains. Nevertheless 

 in other deposits probably of the age of these gravels, such as 

 some of the caves near Liege described by Schmerling, the scattered 

 bones of man have been found in association with a like mammalian 

 fauna. 



The Low-level Gravels. — Connected with this subject is the exca- 

 vation of the valleys, and the duration of that operation. The 

 author mentions how he hesitated to assign at first a much higher 

 antiquity to the higher gravels than to the lower gravels, or rather, 

 admitting a difference of age, to decide whether the excavation of the 

 valleys might not have been effected by some more powerful agency 

 acting through a short interval of time, and by so much contracting 

 the period by which the St. Acheul deposit preceded that of St. 

 Roch ; but after repeated visits to Amiens, and looking at the ques- 

 tion from every point of view, he finds himself unable to discover a 

 sufficient explanation in the direction first sought, and obliged to 

 adopt, in part, views differing materially in some points from those 

 he at first thought to be the more probable. The low-level gravels 

 have been frequently described, and the author confines himself 

 chiefly to pointing out the difference between them and the high- 

 level gravels. The climate at the one period has been described as 

 one of considerable severity ; but there is evidence to show that in 

 some part of the pliocene period, previous to that time, the cold 

 was still more severe. At the period referred to the greater part of 

 England was under the sea, whereas Switzerland and the greater 

 part of France had emerged at an earlier or a miocene period, and 

 there is no sufficient proof of their having been subsequently sub- 

 merged. This was the period of the wonderful extension of the old 

 European glaciers, which descended in the Swiss Alps, the Jura, 

 and the Vosges to within 1200 or 1000 feet of the sea-level, the 

 existing glaciers standing at 3400 to 3500 feet. M. Leblanc has cal- 

 culated that such a difference of level might be accounted for by a 

 reduction in the mean annual temperature of 12|° Fahr. ; but the 

 author questions this, as the gradients of the glacier beds were much 

 less after they had emerged from the mountain-passes. The growth 

 of the old glaciers is rather the result of the great cold than a mea- 

 sure of it. Still it can be conceived that their growth would be 



