206 GLACIAL GKAVELS OF MAINE. 



washed by the rams or other means. At the base of the hill (after a fall of 

 about 100 feet) the gravel spreads out into a narrow fan-shaped series 

 of several ridges situated side by side. These ridges extend a short dis- 

 tance out into the valley of a small stream which flows southwestward into 

 the Androscoggin River. This valley is covered by a sheet of sedi- 

 mentary clay and coarse sand to a breadth of one-fourth of a mile. These 

 sediments overlie the glacial gravel ridges. On the south they are con- 

 tinuous with the high alluvial terraces of the Androscoggin. 



The ravine on the side of the hill must be accounted for. The till of 

 this portion of Franklin County is collected into a great number of long 

 lenticular masses with smooth outlines, and is remarkably free from steep 

 ridges or hummocks or depressions. This ravine has every appearance of 

 having been cut into the deep sheet of till which covei's the hillside. No 

 stream flows in this ravine except in time of rains, and the ravine reaches 

 to the top of the hill. The ridges at the bottom of the hill have steep 

 slopes on both sides, and could not be formed as a delta at its base by an 

 ordinary surface stream eroding the till on the hillside and sweeping the 

 eroded matter down into the valley. Usually the glacial gravel is piled 

 above the surrounding level, and there is no evident depression showing an 

 erosion of the till, betraying where the kame stuff came from. But here, 

 as in several other places, a channel with steep lateral banks is cut into the 

 till. A fair inference from all the facts is that a stream flowing between ice 

 walls here flowed down the hill and eroded the ravine in the till and carried 

 the material down into the valley. The terminal ridges must have been 

 formed between ice walls. Beyond the ridges the plain of alluvium in the 

 valley may be in part composed of the finer sediment brought down by 

 this small glacial stream, if the stream dates from a late period when the. 

 ice was retreating up the valley, as was probably the case. 



CANTON-AUBURN SYSTEM. 



A broad mountain cirque between high hills is situated in Weld, Car- 

 thage, Mexico, and Dixfield. This valley is drained southward into the 

 Androscoggin River at Dixfield. Considerable alluvium is found in the val- 

 ley, most of which appears to be valley drift, i. e., frontal overwasli, but 

 with some signs of an osar-plain along the axis of the valley ; and tlie same 

 can be said of the valley of Swift River in Byron, Roxbury, Rumford, 



