Glacial Phenomena of Canada. 327 



Dorchester Street, correspond to Dr. Dawson's Leda-clay and 

 Saxicava-sand. 



Between the lowest terrace and the river there is a broad marsh, 

 including patches of recent freshwater shells. It is part of the old 

 course of the St. Lawrence ; and on its surface (the lighter drift 

 having been removed) the boulders that once studded the clay have 

 been concentrated. Similar terraces occur on the banks of the 

 Ottawa. The country is strewn with boulders of gneiss and meta- 

 morphic limestone, from the neighbouring Laurentine chain, mixed 

 with more local debris ; and here also it seemed, in several cases, 

 as if, by removal of the lighter material, the boulders were more 

 concentrated on the lower than on the highter terraces. Many 

 of the blocks are rounded ; in this respect differing markedly 

 from the majority of those on glaciers, in moraines, and probably 

 from those transported by icebergs, which, derived from glaciers 

 that reach the sea-level, obtaiu their debris by the fall of rocks 

 and stones on their surfaces from inland cliffs. In the American 

 hills which I saw, there are no signs of true glaciers like those of 

 the Alps having existed ; and the boulders have been transported 

 by floating ice from old sea-shores, where they had been long ex- 

 posed to the washing of the waves. 



At Hawksbury Mills I crossed the Ottawa with Sir William 

 Logan, and penetrated part of the Laurentine hills lying several 

 miles from the north bank of the river. Waterworn gravel here 

 and there rises nearly to their summits, now rarely more than 

 500 or 600 feet above the river. 



In the range about eight miles north of the Ottawa, there are 

 well-rounded and occasionally grooved surfaces of gneiss greenstone, 

 and quartz-rock, — the striations, where I saw them, running 10°. 

 and 20Q W. of S. 



In many places, among the hills, numerous half-rounded boul- 

 ders (of the same substances as those that strew the plains of the 

 Ottawa and the St. Lawrence) cover the ground, and appear as 

 if they had been waiting their turn for glacial transportation, ere 

 the country was raised above the sea. These general signs existing 

 in this chain, in latitude 45J Q N., gave me more perfect confidence 

 in the universal glacial abrasion of the hills on the coast of La- 

 brador in a latitude nearly 150 miles further north. 



Glacial Drift of the Plains ; Strim and Roches moutonnees. 

 — I need not indulge in repeated descriptions of the drift that 

 -covers the plains of Canada and the northern States, It is 



