GLACIAL DRIFT. 261 



nying heliotype. The two upper figures show the opposite sides of the 

 same pebble — nearly of the natural size — of a mica slate, not of remote 

 origin. On one side the stria: run at a small angle with the longer axis 

 of the pebble. On the reverse side the lines are irregularly disposed. 

 The lower left-hand view shows an argillaceous schist, derived from 

 ledges five or six miles distant, of oblong shape, three inches long, and 

 the strice on both sides are approximately parallel to the longer axis. 

 The whole surface on every side has been glaciated, some of the depres- 

 sions being deeper than the others. The other view is of a Huronian 

 schist, derivable from ledges three to twenty miles away, 12 inches long, 

 7 wide, and 3 thick. The upper end has been partially encrusted with 

 carbonate of lime of more recent origin than the strize. The opposite 

 flat sides are scratched parallel to each other, and the longer axis of the 

 stone. The ends are rough. This represents the shape and peculiarity 

 of the striation of a majority of glaciated boulders. 



The following varieties of material have been found in company with 

 these heliotyped boulders upon the north side of Mink brook, about a 

 mile east of the brick church at Mill Village: Hornblende schist, dia- 

 base, blue and gray quartzite, clay slate, serpentine, red quartz, red sand- 

 stone, and gneiss. The cliff is 40 feet high, the upper ten feet of upper 

 till containing limestone. 



These boulders must have been brought by the south-east current, 

 some of them 65 or 70 miles. I think there is a notable absence of the 

 Bethlehem gneiss among them. In the north part of the town the drift is 

 very thick on the northern slopes. On following Mink brook to its source, 

 in the south-east corner of the town, other similar ground-moraines occur. 

 The same are more abundant south of Hayes hill in the edge of Leba- 

 non. A tributary of the Mascomy has cut through this deposit, produc- 

 ing by erosion terraces of till. The surfaces of all these moraines are 

 smooth, indicating the sliding of a glacier over them. Between Prospect 

 and Corey hills is a smooth depression rising gradually to the curved 

 water-shed between the stream flowing west and Mink brook. Scarcely 

 any boulders occur on this basin ; but after beginning the descent to Mill 

 Village, coarse moraines and large rough boulders, twelve and fifteen feet 

 through, abound. It would seem that the glacier broke off the fragments 

 from the ledges of the smooth area, carried them to the brink of the 

 VOL. III. 34 



