168 GLACIAL GRAVELS OF MAINE. 



CLINTON-ALNA SYSTEM. 



This notable gravel system appears to begin in the southeast part of 

 Canaan. It takes its course to Clinton Village by a line which in general 

 is quite straight, but has many minor meanderings. It is here a nearly 

 continuous osar. At Clinton it turns southwest and follows the valley of 

 the Sebasticook River for about 3 miles, and here it is somewhat discontin- 

 uous, either because it was so deposited or on account of .erosion by the 

 river. About halfway between Clinton Village and Benton Falls the 

 gravel leaves the valley of the Sebasticook and turns southward over a 

 rolling country in Benton, Winslow, and Albion, being osar-like in form, 

 but with several gaps at long intervals. From China southward the series 

 becomes conspicuously discontinuous, the short ridges being separated by 

 intervals up to more than a half mile in length. The system follows the 

 west shore of China Pond, passing a short distance west of South China, 

 and at Chadwicks Corner, in the south part of China, expands into a plain 

 near a mile long and more than half as broad. This plain ends in a rather 

 steep bank on all sides. A well 73 feet deep, dug at a point on the slope of 

 the plain, and probably 50 feet below the top, did not penetrate the sand 

 and gravel. Overlying this plain is a scattered drift closely resembling 

 till and containing many bowlders of shapes characteristic of the till. South 

 of this point is a series of lenticular domes separated by the usual intervals; 

 then a broad plain near a half mile wide extending from West Windsor to 

 a point 2 miles south of Windsor Village. This plain is rather level on 

 the top, except that here and there are shallow basins and one deep lake 

 basin. These plains are everywhere covered at the base by the marine 

 clays, and are sprinkled on the tops and flanks by angular bowlders. The 

 same sort of bowlders are scattered over the clays, though not so abun- 

 dantly as on the higher gravel hills. They are probably of ice-floe origin. 

 In Whitefield the gravel takes the form of a discontinuous series of short 

 narrow ridges separated by numerous intervals of the usual length. It 

 approaches the Sheepscot River near North Whitefield, follows this valley 

 for several miles, and then in the southern part of Whitefield and northern 

 part of Alna it expands into a delta-like plain three-fourths of a mile in 

 breadth and nearly twice that length. This plain is situated on the tops of 

 the hills, 50 to 100 feet above the Sheepscot River. South of this plain 



