NOETH WATEEFOED BEANCH. 253 



very fine gravel. It skirts the western base of Pleasan , Mountain and the 

 eastern side of Kezar Pond and two other small ponds in Fryeburg. The 

 oi'igin of these ponds is discussed elsewhere. 



For 25 miles this great series is seldom less than one-fourth of a mile 

 wide, and it often has three or four times that breadth. No central domi- 

 nant ridge could be distinguished at the places examined. If such there 

 was, it has been covered by the sediments which were brought down by the 

 rush of the vast river which in later times swept down this broad thorough- 

 fare of waters. The great volume of the sediments is strongly in favor of 

 the hypothesis that there was an overflow from the Androscoggin Valley 

 southward through Bethel and Albany before the melting of the ice. 



It thus appears that at North Waterford there were two valleys widely 

 diverging and that glacial gravels were deposited in each valley. The val- 

 ley of Crooked River is not only a slope of natural drainage, but it is also 

 more nearly parallel with the general direction of the ice movement in that 

 region. Yet by far the larger overflow was southwest, along a route more 

 transverse to the glaciation and over a low divide, rather than down the 

 drainage slope. The breadth of the gravel plain along the Crooked River 

 is as great as that of the Kezar Brook series. Both series were deposited 

 in cliannels that were probably broad enough to carry off all the waters 

 that came from the north without the aid of the other cliannel. 



The history of the glacial gravels of this region is probably as follows: 

 Originally a large glacial river flowed from Albany (and perhaps from 

 Bethel and the Androscoggin Valley) south to North Waterford and along 

 the valley of Kezar Brook southwestward to Lovell and thence south to the 

 Saco River. At first this river flowed in a narrow channel within the ice. 

 Subsequently other ridges were deposited in channels near the original one. 

 By degrees these channels became confluent and the channel broadened, 

 and an osar-plain was laid down in the broad channel. During this time 

 the valley of Crooked River was blocked by ice, so that the glacial river 

 easily flowed southwest over the divide. But the time came, toward the 

 last of the Ice period, when the waters effected a passage from North Water- 

 ford eastward down the valley of Crooked River. At this time the melting 

 had proceeded so far that the valley was bare of ice from Sebago Lake 

 north to East Waterford. Hence glacial gravel was formed from North 



