THE GREAT ICE AGE 349 



than thirty miles distant, from which they must have been 

 drifted to their present position. This boulder belt, which 

 extends from the lowest tide mark about fifty feet or more 

 upward, is sometimes piled in ridges and sometimes flattened 

 out into a rude pavement. It is a product of the modern 

 field ice, which, attaining a great thickness in winter, has 

 boulders frozen into its bottom, and floating up and down 

 with the tide, deposits these on the shore. At Little Metis, 

 two hundred miles below Quebec, where I have a summer 

 residence, I have from year to year cleared a passage through 

 the boulder belt for bathing and for launching boats, and 

 nearly every spring I find that boulders have been thrown into 

 the cleared space by the ice, while one can notice from year 

 to year differences in the position of very large boulders. 



If we pass inland from the shore belt of boulders, we shall 

 find similar appearances on the inland terraces at various 

 heights, up to at least 400 feet. These are inland boulder 

 belts belonging to old shores now elevated. Like the modern 

 boulder belt these inland belts and patches consist partly of 

 Laurentian rocks from the North Shore, partly of sandstones 

 and conglomerates in place near to their present sites. In 

 some places the stones are smaller than those of the present 

 beach, in other places of gigantic size. These boulders lie 

 not only on the bare rock striated in places with ice grooves 

 pointing to the north-north-east ; but on the old till or boulder 

 clay, which also abounds with boulders, and which is more 

 ancient than the superficial boulder drift. Locally we find 

 here and there masses of fossiliferous limestone which must 

 have been derived from the high ground to the south of the 

 St. Lawrence, and which have been borne northward either 

 by drift ice or by local glaciers. 



If now we study the polished and scored surfaces of rocks 

 in the St. Lawrence valley and the bounding hills, we shall 

 find that while the former testify to a great movement of 



