198 . Tertiary. 



ing, rounding, scratching and furrowiug of the ledges over which the 

 drift materials have passed, and unless these ledges have been decom- 

 posed upon their surfaces, they are covered with scratches or strise, 

 usually parallel to one another, and indicating the course of the drift 

 agenc3^ Ledges of talcose and argillaceous rocks preserve these mark- 

 ings the most distinctly. Were the rocks of Maine laid bai'e, fully half 

 the surface would show these marks of smoothing. 



■ The course of the striffi in Maine vary from north 70 deg. west to 

 north 80 deg. east. 



At the Lubec lead mines, a series of striae were observed upon the 

 side of a perpendicular wall, following the course of the wall around a 

 corner. The course of the striae ultimately varied at right angles from 

 their original directions. At several places at the sea shore the striae 

 have been noticed below high water mark, and others wei-e seen to run 

 under the ocean at low-water mark. The course of the striae upon the 

 lakes north of the Katahdin mountains have more of an easterly course 

 than those to the east and south of the same mountains. It looks as 

 if the mountains formed an obstruction around which the striating 

 agency operated, in preference to climbing the elevation. It is a curious 

 fact, in the same connection, that the striae are wanting on the sum- 

 mit of Katahdin. It appears also that there was another deflection of 

 the course of the striae in the valley of Sandy river. Mt. Abraham 

 maj' have arrested the drift current on the north and turned it into 

 Sandy river valley on the west, from which deflection it struck against 

 the Saddleback mountain range, continued to Mount Blue, and was 

 then directed toward French's Mountain in Farmington. 



Drift striae are never found upon the south side of mountains, unless 

 for a shoi't distance, where the slope is very small. It is comipon to 

 see difl"erent courses of striae intersecting one another, as on the south 

 side of Chamberlin lake, where striae north 70 deg. west and north 50 

 deg. west intersect, and north 17 deg. west and north 67 deg. west, in- 

 tersect. 



The only examples of glacial markings discovered, in Maine, are on 

 the St. John river, in its upper portion. Above the Lake of the Seven 

 Islands, on this river, there are no glacial markings, unless the 

 scratches upon the pavement of bowlders are to be referred to them. 

 The bed of the river is full of stones, and upon the banks below high- 

 water mark they are as firmly set as paving stones in the streets of a 

 cit^y. The scratches are not as constant and distinct as those of the 

 glacier below, and may possibly have been formed by ice freshets in 



