238 GLACIAL GRAVELS OF MAINE. 



lake, and this disproves the theory that the lake or the sea stood at this ele- 

 vation. This clay is probably osar border clay deposited in a ver}^ broad 

 channel within the ice at a very late period of the Ice age. 



This system lies in a region where the rocks are chiefly granitic and 

 the till is very abundant. Although not long, it contains a very large 

 amount of gravel. 



GKAY-NORTH WINDHAM SERIES. 



On the eastern side of Little Sebago Lake is a high range of hills 

 which extends continuously northward to Poland. At a point about west 

 of Gray Village a discontinuous series of short ridges of glacial gravel 

 begins near the eastern base of this high range. At the north end the 

 gravel is but little waterworn, and it is separated from the Gray-New 

 Gloucester plains by a hill more than 100 feet high. For these reasons I 

 regard this series as distinct from the Portland system, although the two 

 series are onlj^ 2 or 3 miles apart in Gray. This series extends southwest- 

 ward, passing about one-fourth of a mile west of West Gray. It soon 

 becomes a continuous osar-plain, and when approaching North Windham 

 rapidly broadens into a delta-plain. Near North Windham it is difficult to 

 distinguish the gravels of this series from those brought down by the large 

 glacial river from Casco and Raymond. Whether this series should be con- 

 sidered a branch of the Casco system is uncertain. If the stream which 

 deposited it began to flow in early glacial time, it would naturally flow into 

 the larger glacial river, but if, as is more probable, it dates from the very 

 last part of the Ice age, then it may have flowed into the sea at North 

 Windham near where the other glacial river also poured into the sea, yet 

 have been distinct from it. 



GENERAL NOTE ON THE GLACIAL GRAVELS OF SOUTHWESTERN MAINE. 



The systems of glacial gravels thu'i far described are not so closely 

 connected with one another in any part of their coiu'ses but that it is rela- 

 tively easy to distinguish them. Most of the gravels remaining to be 

 described are connected with one another not only at the great marine 

 delta-plains which were deposited at elevations from 175 to 230 feet above 

 the sea, but also by transverse branches connecting the broad plains of 

 reticulated ridges found above 230 feet. Some of them are also connected 

 by lateral branches at points north of the plains of reticulated kames in 



