VIII NOTES BY THE EDITOR 



Georgia a mound ten acres in area, and Laving an average height 

 of live feet, chiefly composed of cast-away oyster shells, throughout 

 which arrow-heads, stone axes, and Indian pottery are dispersed. If 

 the neighboring river, the Alatamaha, or the sea which is at hand, 

 should invade, sweep away, and stratify the contents of this mound, it 

 might produce a very analogous accumulation of human implements, 

 unmixed perhaps with human bones. Although the accompanying 

 shells are of living species, I believe the antiquity of the Abbeville 

 and Amiens flint instruments to be great indeed if compared to the 

 times of history or tradition. I consider the gravel to be of fluvia- 

 tile origin, but I could detect nothing in the structure of its several 

 parts indicating cataclysmal action nothing that might not be due to 

 such river-floods as we have witnessed in Scotland during the last half- 

 century. It must have required a long period for the wearing down of 

 the chalk which supplied the broken flints for the formation of so 

 much gravel at various heights, sometimes one hundred feet above the 

 level of the Somme, for the deposition of fine sediment including 

 entire shells, both terrestrial and aquatic, and also for the denudation 

 which the entire mass of stratified drift has undergone, portions hav- 

 ing been swept away, so that what remains of it often terminates 

 abruptly in old river-cliffs, besides being covered by a newer unstrati- 

 fied drift. To explain these changes I should infer considerable 

 oscillations in the level of the land in that part of France, slow 

 movements of upheaval and subsidence, deranging but not wholly 

 displacing the course of the ancient rivers. Lastly, the disappear- 

 ance of the Elephant, Rhinoceros, and other genera of quadrupeds 

 now foreign to Europe, implies, in like manner, a vast lapse of ages, 

 separating the era in which the fossil implements were framed and 

 that of the invasion of Gaul by the Romans. Among the problems 

 of high theoretical interest w r hich the recent progress of Geology and 

 Natural History has brought into notice, no one is more prominent, 

 and, at the same time, more obscure, than that relating to the origin 

 of species. On this difficult and mysterious subject a work will very 

 shortly appear, by Mr. Charles Darwin, the result of twenty years of 

 observation and experiments in Zoology, Botany, and Geology, by 

 which he has been led to the conclusion, that those powers of nature 

 which give rise to races and permanent varieties in animals and 

 plants, are the same as those which, in much longer periods, produce 

 species, and, in a still longer series of ages, give rise to differences 

 of generic rank. He appears to me to have succeeded, by his inves- 

 tigations and reasonings, to have thrown a flood of light on many 

 classes of phenomena connected with the affinities, geographical distri- 

 bution, and geological succession of organic beings, for which no 

 other hypothesis has been able, or has even attempted, to account. 

 Among the communications sent in to this Section, I have received 

 from Dr. Dawson, of Montreal, one confirming the discovery which 



