VI 



THE OLD ICE-FLOOD 



HE was a bold man who first conceived the idea 

 of the great continental ice-sheet which in 

 Pleistocene times covered most of the northern part 

 of the continent, and played such a part in shaping 

 the land as we know it. That bold man was Agas- 

 siz, who, however, was not bold enough to accept 

 the theory of evolution as propounded by Darwin. 

 The idea of the great glacier did not conflict with 

 Agassiz s religious predilections, and the theory of 

 evolution did. It was a bold generalization, this of 

 the continental ice-sheet, one of the master-strokes 

 of the scientific imagination. It was about the year 

 1840 that Agassiz, fresh from the glaciers of the Alps, 

 went to Scotland looking for the tracks of the old 

 glaciers, and he found them at once when he landed 

 near Glasgow. We can all find them now on almost 

 every walk we take to the fields and hills; but until 

 our eyes are opened, how blind we are to them! 

 We are like people who camp on the trail of an 

 army and never suspect an army has passed, though 

 the ruts made by their wagons and artillery and 

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