328 Glacial Phenomena of Canada. 



enough to say that the descriptions given by previous writers ara 

 strictly correct. The whole country is literally covered with drift, 

 — to such an extent, indeed, that except in denuded water-courses 

 and deep gorges, like those of the Genesee and Niagara, it is only 

 in rare cases that the rock is exposed. Even railway-cuttings 

 rarely penetrate to the rocks below. It may be compared, in Eu- 

 rope, to the northern plains of Germany. In horizontal extension 

 it is the most widely spread of all deposits ; and even in thickness 

 it rises to the dignity of a great formation, having by Logan and 

 Hall been estimated in places at 500 and 800 feet in thicknessf . 

 In all cases the Laurentian boulders, which have often travelled 

 hundreds of miles, are mixed with fragments of the rocks that 

 Crop out northward towards the Laurentine hills, and with stones 

 from the strata of the immediate neighbourhood, — the number of 

 the component materials of the drift thus generally increasing to 

 the south/};, marking the fact that the lowlands as well as the 

 mountains have been subject to the denuding and transporting, 

 agency of ice. At a distance from the mountains, the boulders 

 become comparatively few ; and it is this admixture of calcareous 

 and other material, often lightened with sand, that fertilizes the 

 soil in the great plains that surround the lakes. 



The City of Ottawa stands on Trenton limestone ; and the surround- 

 ing country is strewn with boulders of Laurentian gneiss and Trenton 

 limestone itself, and of Potsdam sandstone, &c. 



Between Ottawa and Prescott on the St. Lawrence, the basement-rock 

 is rarely seen. The country is chiefly covered with gravel containing 

 boulders of gneiss from the hills, and of Silurian rocks from the plains. 

 Here and there are patches of sand containing pebbles and small bouldersj 

 generally rounded. In some places it has the appearance of blown 

 sand, — an effect that may have been produced as the land emerged from 

 the sea. 



The shores of Lake Ontario, in general, consist of low and shelving 

 slopes of drift ; but at Scarborough bold cliffs of sand, gravel, and clay 

 partly white with boulders, rise 320 feet above the lake. The terraces 

 of Toronto have been described by Sir Charles Lyell. They are like 

 those of the St. Lawrence and the Ottawa. The lower part of the city 

 stands on a very stiff boulder-clay, containing large and small boulders, 

 many of them scratched. Somewhat higher there are beds of beauti- 



f I had an opportunity of examining the drift in many places between* 

 Quebec and London (which lies between Lake Huron and Lake Erie) 

 about 500 miles from N.E. to S.W. in a direct line, and from north to> 

 south between Montreal and Ottawa, to Blossburgh and New York. 



% See Murray's Report, Geological Survey of Canada, 1856 k 



