384 GLACIAL GRAVELS OF MAINE. 



the ice after it had once retreated northward of this point. Any great 

 readvance wonld imply general or climatic increase of intensity of glacial 

 conditions. If so, we ought to find similar moraines all along the coast. 

 The few short moraines certainly demand pauses in the retreat of the ice, 

 and they may indicate a readvance. In either case the moraine must have 

 been formed while the ice was in motion. The conclusion follows that if 

 the ice was not stagnant at the time of the moraine it could not have been 

 at any time previous. Its motion at the time of the deposition of the 

 moraine was a continuation of the motion it had had previously and con- 

 tinuoLTsly. The situation of the place was here favorable to the continuance 

 of the flow up to the last. 



Three inferences are indicated. 1. The Waldoboro system of discon- 

 tinuous gravels was formed while the ice was in motion. 2. The osar 

 beneath the moraine proves that the thin ice of that time (less than 200 

 feet in thickness) could flow over gravel ridges or domes without pushing 

 them forward. 3. This gravel was probably deposited in a subglacial 

 channel. 



In the valley of Georges River, and also near Belfast, we find several 

 discontinuous systems of gravels. In these localities the direction of the 

 ice flow during the last part of the Grlacial period was many degrees different 

 from the earlier flow, as is conclusively proved by two or more series of 

 glacial scratches. The systems of lenticular eskers follow the direction of 

 the scratches last made. They date, then, from a late period, when the ice 

 could no longer flow over the higher hills, but was forced to flow around 

 them. 



The fact that the series of lenticular eskers are so nearly parallel with 

 the direction of ice flow favors the hypothesis that they were formed 

 beneath the ice by subglacial streams. In several places, as near Union, 

 the surface layers of the northern sides of the lenticular gravel hills are 

 crumpled and distorted, while beneath these layers the stratification is, in 

 the cases observed, perfect. Such surface distortion might result from the 

 direct pressure of ice flowing over the gravel hillock, or it may be due to 

 the settling of gravel deposited over ice. Thus it is possible that pieces of 

 ice containing morainal matter may break away from the roofs of timnels 

 and be rolled along for a time like stones. If such were deposited as a 

 part of a mass of glacial gravel, the melting of the ice subsequently would 



