268 GLACIAL GEAVELS OF MAINE. 



surfaces. They show greater numbers of rounded bosses, or roches 

 moutonndes, and many small rock basins. These depressions are glaciated 

 even to the bottom. I have not been able to find in granite areas surfaces 

 of preglacial weathering, except at certain cliffs facing the south. For 

 instance, at the southern brow of Russell Mountain, in Blanchard, there is a 

 steep cliff several hundred feet in height. The upper portion has been 

 shattered by the elements into a wall of bowlders of decomposition, most 

 of them still occupying their original relative positions. Some of the 

 largest of the upper tier of bowlders have been moved several feet south- 

 ward, so as almost to cause them to fall down the cliffs. The top and 

 northern slopes of the hill are intensely glaciated, and they so far bore the 

 brunt of the attack that the ice only partially succeeded in pushing these 

 bowlders from their places. Doubtless on that cliff in preglacial time there 

 rested many a bowlder which the ice was afterwards able to push over the 

 brink and carry away. The turrets and battlements of the castle as the 

 glacier found it have been cut off, and perhaps the upper stories, but 

 enough remains to remind us that the power of ice has some limit. 



The condition of the surface of the glaciated rock in Maine proves 

 that the behavior of a tliin glacier, such as the extremities of those of 

 Switzerland and Norway to-day, is very different from that of one a half 

 mile or more in thickness. Under the deep ice of the time of maximum 

 accumulation only here and there a small depression became filled by sub- 

 glacial till or by embayed ice, so that the glacier flowed over it as if it had 

 been solid rock. We have seen that the bottoms of most of the narrow 

 furrows were glaciated even when transverse to the direction of the motion. 

 It was very different during the last of the Glacial period, when the ice had 

 become thin. Thus, at one of the lime quarries at Rockland, in a north- 

 east and southwest valley, there is an earlier series of long, straight 

 scratches bearing S. 31° W. Later scratches are found which in places 

 have obliterated the earher ones. They bear S. 51° W. The smooth, 

 even surface of the limestone ledge gently inclines southwestward about 

 1 foot in 40. On this incline there is a steeper place where within 3 feet 

 there is a fall of 3 or 4 inches. The later scratches come up to the northern 

 edge of the steeper incline, when they disappear for about 3 feet, then begin 

 again near the foot of the steep incline and continue southward. The 

 steeper slope is beautifully glaciated, but the scratches were made during 



