KING — GLACIAL AND POST-GLACIAL DEPOSITS. 



171 



were considerably eroded by glaciers during the close of the Pliocene 

 period. 



Before entering on the next subject, it is necessary for me to men- 

 tion that I wish the greater part of the insertions in the table to be 

 taken in an approximate sense ; a few of them, such as " Irish Round 

 Towers," are offered suggestively. 



Remarks on the Phenomena of the Glacial and Post- Glacial periods 

 noticed in the Table. 



The two periods under immediate consideration are strongly dif- 

 ferentiated both by their physical and organic features. It is unne- 

 cessary to add more to what has already been stated on the former. 

 The Glacial period was characterized by the presence of species of the 

 genera Elephas, Rhinoceros, and Hippopotamus, doubtless as amply 

 protected against a severe frigid climate as the Bear, Walrus, Musk 

 Buffalo, Balene Whale, now inhabiting the ice-bound regions of the 

 Arctic Circle. The Post- Glacial period appears to have been always 

 marked by the absence of the genera above named, at least in the 

 area of the British Isles. The shells special to the glacial period are 

 such as still inhabit the Arctic seas : a few, but very few, may have 

 become extinct. Whether any new species have come into existence 

 during the Post- Glacial period is a question which I am unable to an- 

 swer ; but it would appear that a few are special to this term, if we 

 confine our observations to the British and adjacent seas, — the fol- 

 lowing species, Lima excavata, Ilaliotis tuberculata,Fusus Berniciensis, 

 and Litorina litoralis, being unrecorded in Glacial and Pliocene de- 

 posits. The genus Homo belongs to both the glacial and post-glacial 

 period : it was represented as early as the close of the subaqueous 

 epoch or the beginning of the second subaerial division of the Glacial 

 period by a low form or extinct species, — a view strongly countenanced 

 by the Neanderthal skeleton, as well as the rudely-chipped flint-imple- 

 ments occurring in the elephant gravels of Amiens, lioxne, and other 

 places. Probably a higher type existed at the same time, as indicated 

 by the skulls found in the Engis caves near Liege. The " Borreby 

 people " of the Post-Glacial period appear to have descended from the 

 Neanderthal race. How far back in geological time it was that the 

 genus made its first appearance on our planet is a question yet to be 

 solved. There is no reason, however, to doubt that it was repre- 

 sented by species during the Pliocene, or even the Miocene period. 



The line of demarcation between any two epochs, also between 

 the Glacial and Post- Glacial periods, I assume as being formed by 

 terrestrial and oceanic conditions corresponding to the present re- 

 lative level of land and sea. 



Glacial Period. 



First (subaerial) epoch. — The elevation of the British area, although 

 the land is assumed to have been thirteen hundred feet { — 2'20 

 fathoms) higher than it is at present, is not, in my opinion, to be 

 regarded as the cause of the severe climatic conditions of this epoch. 



