128 GLACIAL GRAVELS OP MAINE. 



small brook no such stones appeared as 23art of tlie till. There is here no 

 proof of a landslide of till from the hillsides, and no proof that till dropped 

 down into a subglacial tunnel from above subsequent to the deposition of 

 the glacial gravel. The evidence strongly favors the following conclusions: 

 (1) The till was first (in order of time) deposited beneath the ice as a ground 

 moraine. (2) Subsequently part of this till was washed away by the glacial 

 river. (3) The fact that a considerable part of the till escaped denudation, 

 notwithstanding the large size of this glacial river, proves that it must have 

 2Dresented considerable resistance to erosion; and this conclusion follows 

 whether we consider that the osar river flowed in a subglacial tunnel or in 

 an ice canyon open to the aii*. (4) The fact, then, that the glacial gravels 

 often overlie uneroded till is not fatal to the theory that the kames and 

 osars were deposited in subglacial tunnels. The fact is, the ground moraine 

 was a very tough, compact mass, and not easily eroded even by a rapid 

 glacial stream. Besides, it is not proved that in all cases subglacial streams 

 wotild erode the till while those flowing in superficial channels would not. 

 (5) The absence of till overlying the osar leaves us without direct proof that 

 the osar river here flowed in a subglacial tunnel. 



At the south end of the Notch the gravel and cobbles spread out into 

 a fan-shaped plain about one-half mile long and half as broad. The plain 

 has been eroded by a small stream which flows southward through its cen- 

 ter, so that the plain of original deposition has been cut into two parallel 

 terraces separated by a valley of erosion. The lateral terraces are also 

 intersected by several transverse valleys of erosion, so that what must have 

 been originally a continuoiis plain is now a series of detached terraces and 

 mounds. The gravel is coarse at the north end of the plain and grows 

 much finer toward the south. It was a small delta, deposited either in a 

 glacial lake or in the sea. The plain is bordered by clay, and a sheet of 

 clay extends from this point all the way to the sea. I found marine fossils 

 in this clay at Kenduskeag Village, a few miles south of this place. It is 

 certain that the sea extended nearly to the Notch, but exactly how far I 

 have not been able to determine. If the clays that border the osar all the 

 way from the Notch southward are not Avholly marine, then we must regard 

 them as osar border clays toward the north, i. e., deposited in the broad- 

 ened osar channel at the sides of the jDreviously deposited glacial gravel. 



South of the gravel plain at the south end of the Notch there is an 



