332 The Drift or Boulder Formation. 



The rock, in short, is a collection of great boulders and blocks of 

 sandstone, which were lying immediately on the strata from which 

 they were derived, when they became enveloped by the succeed- 

 ing formation. The whole is planed to a smooth tesselated sur- 

 face, and marked with parallel grooves. In the same vicinity, the 

 parallel grooves occasionally appear on the flat surfaces of 

 successive step?, formed by one layer of sandstone resting on 

 another. They, however, do not always come up to the vertical 

 sides of the steps, and these ungrooved parts are usuall}'- rough 

 and uneven, as if they had but recently been fractured or deprived 

 of their protecting cover. The Company's post stands on a point 

 ou the east side, which cuts the lake nearlv in two, at about eiofh- 

 teen miles from the head, and it is opposite a less prominent point 

 on the other side. These points approach to within a quarter of 

 a mile of one another. Both are composed of sand and gravel, 

 which on the east form a hill 130 feet hin-h. The southern 

 face of this hill runs in the bearing 65?, and the gravel towards 

 the eastward rests on flat sandstone strata, which have a smooth 

 and partially rounded surface. The gravel and the rock constitute 

 the north side of a deep bay. The polished rock surface exhibits 

 well marked grooves, which come from beneath the gravel hill, 

 neai-ly at right angles to the margin of the water. There is here, 

 as in some other instances, more than one set of parallel scratch- 

 es. Two of these sets cross one another in the directions 140 '? 

 and 196°. The gravel may once have been continuous across the 

 lake, and may have been broken or worn down for the escape of 

 the water, which now flows past in a gentle current through the 

 gaj). The mass is not unlike the remains of an ancient moraine, 

 and, combined with the smooth rounded surfaces and parallel 

 grooves and scratches, and the changes in their direction, the 

 circumstances of the case may well suggest that this part of the 

 valley of the Ottawa may have been the seat of an ancient glacier. 

 A difficulty appears to stand in the way of the hypothesis, in the 

 horizontality of the valley. There is little fall in it for seventy 

 miles, and the total height of the lake above the sea is only 612 

 feet. What descent there may be in the valleys which lead into 

 it on the north, having their origin in the watershed, about forty- 

 five miles distant, in which the ice behind might press on the ice 

 before, has not yet been ascertained, but it is not reported to be 

 very great. But as Professor J. D. Forbes appears to have 

 demonstrated, in his Travels through the Alps, that in glaciers 



