224 WAKREN UrHAM, ESQ., ON CAUSES OF THE ICE AGE. 



a grand array of geologists who have been quite equal to dealing 

 with the magnificent phenomena with which that great continent 

 abounds, and we in Europe — in the old country — ai-e now deriving 

 the benefit of these new ideas coming across the Atlantic to us, 

 and getting us a little out of the rut into which we were falling. 



The two principal points that the author deals with in the 

 paper are, I think, briefly these. The first is as regards the 

 length of time — so many thousands of years — which was necessary 

 to bring into existence the great Ice Age, and to see it to its close ; 

 and the second is the question, on what phenomena are we to base 

 our conclusions as regards the origin of that great Ice Age. Yoit 

 will have seen from the paper that there are two extreme views as 

 regards the length of period — the one astronomical, of which Dr. 

 Croll may be considered the author, and the other geological, of 

 which I think I may say Lyell, followed by Dana, Le Conte and 

 equally by the author of the paper, ai'e the exponents. You have 

 seen that the differences in periodic lengths are enormous between 

 these two extremes ; and if I might be allowed, as an old geologist 

 myself, to some extent to give my own view, I might say I entirely 

 concur with the author of this paper as regards the length of time. 



I have visited, explored, and described glacial phenomena over 

 a very large portion of the British Isles, and it is impossible, I 

 think, to observe the freshness of the glacial strioe and terraces, 

 and the polishing of the rock surfaces, without coming to the 

 conclusion that the geological epoch is, comparatively speaking, 

 exceedingly recent. Just consider for a moment ; — the phenomena 

 that have been left by the old glaciers of the British Islands have 

 not yet entirely disappeared, nor have those of the former enormous 

 glaciers of the Alps and other ranges. They consist of boulders 

 and moraines on the one hand, and polishing of the rock surfaces 

 on the other ; and it seems to me unquestionable that if the period 

 since the disappearance of glaciers were of the enormous length 

 held by Dr. Croll and his followers Professor James Geikie and 

 others, that the whole of these evidences of the glacial period would 

 have entirely disappeared. The streams, torrents, and atmospheric 

 agents would have swept away these accumulations, and also have 

 completely obliterated the beautiful striations which we find on 

 the rock surfaces. In some districts, in fact, you. have only to 

 take the sod off, lift it off carefully, and there you find the surface 

 beautifully glaciated ; and if the period had been of such vast 



