1858.] that have influe^iced the Scenery of Canada. 523 



chain. The upper plain is chiefly formed of Upper Silurian and 

 Devonian strata. East of the Hudson, the Lower Silurian rocks 

 that form the lower plain of Canada become gradually much dis- 

 turbed and metamorphosed, and at length rising into bold hills 

 trending north and south, form in the Green Mountains part of the 

 chain that stretches from the southern extremity of the Appalachian 

 Mountains to Gasp^, on the Gulf of St. Lawrence. Between the 

 plains of the lakes and this range, the steep terraced mass of the 

 Catskills, formed of old red sandstone, lies above the Devonian 

 rocks facing east and north in a grand escarpment. 



The whdle of America south of the lakes, as far as latitude 40% 

 is covered with glacial drift, consisting of sand, gravel, and clay, 

 with boulders, many of which, during the submergence of the country, 

 have been transported by ice several hundred miles from the 

 Laurentine chain. Many of these are striated and scratched in a 

 manner familiar to those conversant with glacial phenomena. 

 When stripped of drift all the underlying rocks are evidently ice- 

 smoothed and striated, the striations generally running more or 

 less from north to south, indicating the direction of the ice-drift 

 during the submergence of the country at the glacial period. The 

 banks of the St. Lawrence, near Brockville, and all the Thousand 

 Islands, have been rounded and moutonnee by glacial abrasion 

 during the drift period. 



The submergence of the country was gradual, and the depth it 

 attained is partly indicated in the east flank of the Catskill moun- 

 tains. This range, near Catskill, runs north and south, about 10 

 or 12 miles from the right bank of the Hudson. The undulating 

 ground between the river and the mountains is seen to be 

 covered with striations wherever the drift has been removed. These 

 have a north and south direction ; and ascending the mountains 

 to Mountain House, the speaker observed that their flanks are 

 marked by frequent grooves and glacial scratches, running not 

 down liill, as they would do if they had been produced by glaciers, 

 but north and south horizontally along the slopes, in a manner that 

 might have been produced by bergs grating along the coast 

 during submergence. These striations were observed to reach 

 the height of 2850 feet above the sea. In the gorge, where the 

 hotel stands at that height, they turn sharply round, trending 

 nearly east and west ; as if at a certain period of submergence, the 

 floating ice had been at liberty to pass across its ordinary course in 

 a strait between two islands. During the greatest amount of sub- 

 mergence of the country, the glacial sea in the valley of the Hudson 

 must have been between 3000 and 4000 feet deep, and it is pro- 

 bable that even the highest tops of the Catskills lie below the 

 water. 



In Wales, it has been shown that during the emergence of the 

 country in the glacial epoch, the drift in some cases was ploughed 

 out of the valleys by glaciers ; but though the Catskill mountains 



