ANOTHER POSSIBLE CAUSE OP THE GLACIAL EPOCH. 155 



view which seems the more reasonable one.* At the same 

 time I agree with Prof. Geikie in doubting that the oscilla- 

 tions of land of the Pleistocene period were to any great 

 extent (if at all) due to the weight of accumulated snow (or 

 its removal), as supposed by Dana. In the view of the 

 occurrence of two cold epochs with an intervening warmer 

 (or interglacial) stage, I have long been a believer, and 

 maintain that it is borne out by the glacial phenomena of 

 the Bi'itish Isles, as I endeavoured to show many years 

 ago,t but such movements were probably not dissimilar in 

 their origin and cause to those of former geological periods 

 to which the crust of the earth has been accustomed. 



Postscript. 



Although it is some time ago since I received the follow- 

 ing letter bearing upon the subject I have taken up in my 

 paper, yet the author is so recognised an authority on Arctic 

 matters that with his permission I quote it. 



Col. H. W. Feildex, F.G.S., writes to me, December 13th, 1896:— 



" I am inclined to think that there is mnch force in your view 

 that the so-called Glacial epoch was due in a great measure to some 

 deflection of the warm current from the Polar Basin. 



" If Professor Spencer is correct the elimination of the Gulf of 

 Mexico would deprive the northern Atlantic of its chief heating 

 apparatus, and might induce glacial conditions over Scandinavia. 

 If a system of glaciation sets in anywhere, where the precipitation 

 exceeds the melting forces, there is no saying where it may end, 

 given sufficient lapse of tirae. 



" There is, however, another side of the proposition, about which 

 I should like your opinion. 



* See on this point a more recent paper by Professor Spencer on 

 " The Continental Elevation of the Glacial Period," Geological Magazine, 

 January, 1898. In this paper the author extends his observations on 

 the great continental uprise to the eastern and northern coasts of the 

 Atlantic, suggesting changes regarding the European and British area far 

 in excess of those referred to by myself for these regions. 



t Physical History of the British Isles, ch. xiii, plates 13 and 14 (1882). 



