262 GLACIAL GRAVELS OF MAINE. 



ranges of hills which then formed islands. A large part of the sands and 

 gravels of this region were deposited in the sea, mostly in the open sea in 

 front of the ice, but in part in broad channels opening on the sea-like bays 

 inclosed at the sides by ice. In this region the gravels are somewhat dis- 

 continuous, and many of the smaller deposits are more or less covered by 

 the marine clays ; they are therefore difficult to trace. I have only partially 

 explored the southern portion of York County. 



ACTONNORTH BERWICK SYSTEM. 



This series of gravels is provisionally described as a distinct system, 

 though this glacial river may have joined that which flowed down the 

 Mousam Valley. If so, it was earl)- in the Ice age, and late in that period 

 these streams poured into the sea b}:- widely separated mouths. The system 

 begins about a mile north of South Acton, on the southern slope of a high 

 hill. For about 2 miles it consists of two nearly parallel series situated 

 about one-fourth of a mile apart. One of them is a series of short ridges 

 and hummocks, forming a single line like the osars, with only a few out- 

 lying and reticulated ridges. These gravels run southeast across the valley 

 of a stream which flows eastward into the Mousam River. It then pene- 

 ti-ates a narrow pass through the hills southward over a divide not more 

 than 50 feet high. In this pass a small stream soon appears, which flows 

 southward past East Lebanon, and the gravel sj^stem follows the same val- 

 ley, most of the way as a narrow osar-plain, now much eroded by the 

 stream. It passes near Lebanon station of the Portland and Rochester 

 Railroad and about a half mile west of Bauneg Beg Mountain, and con- 

 tinues south and east through North Berwick into Wells. As already 

 stated, the system near South Acton is double. The more western gravels 

 begin near the other series, but keep about 100 feet above it on the hillside. 

 They take the form of a small two-sided ridge or osar with very steep lat- 

 eral slopes and a very meandering course. The material is but little water- 

 worn. Within about 2 miles it comes down the hill to near the other series 

 in the valley, and is then lost. No doubt it was deposited by a small tribu- 

 tary of the main glacial river. This little osar-ridge is situated 400 feet or 

 more above the sea, and the difference between its steep side slopes and the 

 low arch of the ridges found below 230 feet is very noticeable. 



From East Lebanon southward this system traverses a gently rolling 



