318 GLACIAL GEAVELS OF MAINE. 



constant renewal of the living glacier. Canj^ous cut in rock exhibit the cumu- 

 latiye ejffects of erosion on a fixed bed. But the ice-sheet of to-day is not 

 that of the last century. Pressing onward from age to age, jvist as new gener- 

 ations of men rise to do the world's work, the worn, rounded, and wasted 

 glacier loses itself at the glance of the sun, before its streams have time to 

 enlarge their channels very greatly, and is replaced by a new and unbroken, 

 youtliful glacier, eager to run its race. The slow inward flow of the ice 

 also assists in preventing enlargement of the channels of the streams. 



In addition to the small narrow ridges we find others broadening to an 

 eighth of a mile or more, with corresponding height, or expanding into 

 massive ridges or mounds one-half to three-fourths of a mile in breadth 

 and a mile or more in length, with a height of 100 to 150 feet. We find 

 hundreds of miles of osar terraces one-eighth to one-half a mile in breadth, 

 level in cross section or with a central ridge rishig above the rest of the 

 plain, going up and over hills or skirting- hillsides as terraces in a way 

 to prove they were at the time of deposition confined on one or both sides 

 by ice. We find cones, domes, mounds, and ridges of very small as well 

 as large size, but all in situations such that they must have been deposited 

 in channels or basins in the ice. We find osar border clay deposited in the 

 broadened channel of an osar river, which is in some cases probably marine — 

 i. e., an osar channel became a fiord in the ice. We find channels of the 

 ice one-fourth mile to a mile wide filled with deltas which at their distal 

 ends are marine. From a diminutive osar like one of the ridges near 

 South Acton or the little gravel hummocks near the Head of the Tide, 

 Belfast, up to the AVhalesback, Aurora, or the so-called "mountains" of 

 Greenbush, or the broad osar terraces of York and Oxford counties, the 

 distance is immense. Before the final disappearance of the ice-sheet it 

 was gashed and pierced and sliced by a complex system of channels, most 

 of the time of large size and irregular shapes. Is this self-destructive! If 

 so, it is no more suicidal than the behavior of a glacier could be exjjected 

 to be that was forced to supply water for its own destruction. The drainage 

 waters of ordinary Alpine glaciers immediately escape, but this ice-sheet 

 went over many transverse hills, and to the north of the hills there were 

 large permanent bodies of water which towai'd the last were eating out its 

 vitals. To complete its misfortunes the sea rose, and by the greater sub- 

 sidence to the northwest it found itself on a bed sloping against it over 



