264 Geological Gleanings. 



strata. East of the Hudson, the Lower Silurian rocks that form 

 the lower plain of Canada become gradually much disturbed 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 Appalatchian 

 Mountains to Gaspe, 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 escarpments 



" The whole 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 hill, 

 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 submergence of the country, the glacial sea in the valley 



