116 THE ICE AGE IN CANADA. 



boulders from the banks off the American coast, from 

 which I had previously recorded travelled stones taken 

 up by the hooks of fishermen which became fixed on 

 organisms growing on them. Off the ends of the Green- 

 land glaciers in Baffin's bay and elsewhere, such deposits 

 must be proceeding on a gigantic scale. The Keports of 

 the " Challenger " show, as already stated, that over vast 

 oceanic areas lying to the north of the antarctic continent, 

 deposits of stones and other debris falling from ice are so 

 abundant as to mask the organic accumulations. In like 

 manner immense deposits of submarine inorganic matter 

 are being deposited in the arctic seas in the track of the 

 icebergs and the drift floe-ice. 



If now we turn to the Pleistocene accumulations on the 

 land, I have shown that throughout the valley of the 

 lower St. Lawrence the old till or boulder-clay contains 

 marine shells, and in the overlying deposits, the upper 

 Leda clay and Saxicava sand, these are extremely abun- 

 dant. Both of these deposits contain far-travelled 

 boulders often of great size, and these have been carried 

 to great heights. On Montreal mountain marine shells 

 occur at an elevation of nearly 600 feet, and at a still 

 crreater height boulders which have been derived from the 

 Laurentian highlands to the north. On still higher 

 terraces, up to 1,200 feet, from Labrador * to the foot of 

 lake Ontario, there are shore beaches and boulders, 

 though in the west they have not afforded marine shells. 



To the southward, Upham has found marine shells in 

 the boulder-clay near Boston up to an elevation of 200 

 feet.-|- It is true this is in Drumlins or detached hills, 



* Richardson. 



t Am. Journal of Science, May, 1889. 



