THE "GREAT ICE AGE." 161 



But this negative anomaly is not all. The ancient glacial 

 deposits are not only remarkable on account of the absence of 

 the most characteristic of modern glacial deposits, but in con- 

 sisting mainly of something which is quite different from any 

 of the deposits actually formed by any of the modern glaciers 

 of Switzerland or any other country within the temperate 

 zones. 



I have seen nothing either at the foot or the sides of any 

 living Alpine or Scandinavian glacier that even approximately 

 represents the ll till " or " boulder clay," nor any description 

 of such a formation by any other observer ; and have met with 

 no note of this very suggestive anomaly by any writer on gla- 

 ciers. Yet the till and boulder clay form vast deposits, cover- 

 ing thousands of square miles even of the limited area of the 

 British Isles, and constitute the main evidence upon which we 

 base all our theories respecting the existence and the vast ex- 

 tent and influence of the " Great Ice Age." 



Although so different from anything at present produced by 

 the Alpine or Scandinavian glaciers, this great deposit is un- 

 questionably of glacial origin. The evidences upon which this 

 general conclusion rests are fully stated by Mr. Geikie, and 

 may safely be accepted as incontrovertible. Whence, then, 

 the great difference ? 



One of the suggestions to which I have already alluded as 

 afforded by reading Mr. Geikie's book was a hypothetical solu- 

 tion of this difficulty, but the verification of the hypothesis 

 demanded a revisit to Norway. An opportunity for this was 

 afforded in the summer of 1874, during which I travelled round 

 the coast from Stavanger to the Arctic frontier of Russia, and 

 through an interesting inland district. The observations there 

 made, and strengthened by subsequent reflections, have so far 

 confirmed my original speculative hypothesis that I now ven- 

 ture to state it briefly as follows : 



That the period appropriately designated by Mr. Geikie as the 

 " Great Ice Age" includes at least two distinct periods or 

 epochs the first of very great intensity or magnitude, during 

 which the Arctic regions of our globe were as completely gla- 

 ciated as the Antarctic now are, and the British islands and a 

 large portion of Northern Europe were glaciated as completely, 

 and nearly in the same manner, as Greenland is at the present 

 time ; that long after this, and immediately preceding the 

 present geological epoch, there was a minor glacial period, 

 when only the now existing valleys favorably shaped and situ- 



