SBBOOIS-KINGMAN-COLUMBIA SYSTEM. 101 



following considerations make it probable that both this plain and the one 

 north of Lead Mountain were deposited in glacial lakes rather than in the 

 sea : First, the contour of 240 feet lies several miles south of here, not 

 more than 3 or 4 miles north of Deblois Village ; second, no marine sands 

 or clays are found in the valley of the Narraguagus far to the noi-th of 

 Deblois, whereas the basin of Beddington Lake ought certainly to be cov- 

 ered with marine clay if the sea formerly extended north of Lead Mountain; 

 third, the fact that the plain south of Lead Mountain ends in a rather steep 

 bank on the west and south is most easily explained on the hypothesis that 

 a glacial lake was there bordered by walls of ice. At Upper Beddington 

 the osar-plain once filled the whole valley of the Narraguagus to a height 

 of 50 feet and a breadth of about one-eighth of a mile, though the river has 

 now deeply eroded the gravel along the axis of the valley. Going north- 

 ward a short distance, we find the glacial gravel leaving the valley and 

 keeping off to the west on ground 30 to 75 feet above the river. Above 

 this point there is but little gravel of any kind in the bed of the Narra- 

 guagus. The valley drift is scanty, and the stones it contains are plainly 

 tillstones, which have lost but little of their till shapes, a great contrast to 

 the very round stones of the osar-plain that fills the valley at Upper Bed- 

 dington. Now, if at the time the delta-plain north of Lead Mountain was 

 being deposited the sea occupied the valley of the Narraguagus as far north 

 as that place, then no reason can be given why the glacial gravel should 

 not spread across the open valley as it did at Upper Beddington, instead of 

 being deposited so abundantly to the west of the river and on land consid- 

 erably higher. These appearances are jiist as if, during the final melting 

 of the ice, a tongue of ice or a local glacier contiimed to flow down the 

 unobstructed north-and-south valley of the Narraguagus, while to the west, 

 in the lee of hills that obstructed the ice flow, the ice had already melted, not 

 being replenished from the north, like the glacier in the open valley. On 

 this theory the ridge of bowlderets and bowlders lying on the east side of 

 the plain north of Lead Mountain may in part be a water-washed lateral 

 moraine of the hypothetical valley glacier. 



The gravels of this series appear on the shores and islands of Bedding- 

 ton Lake and then expand into broad, ratlier level-topped i^lains that are 

 continuous with the great Deblois-Columbia plains, which will be described 



