LEWISTON-DUEHAM SEEIES. 



205 



The length of the Lewiston series is 9 miles; that of the West Durham 

 series, 5 miles. 



HILLSIDE BSKERS IN JAY AND WILTON. 



About 1^ miles south of Beans Corner, in Jay, is a good specimen of 

 the short sidehill systems as they appear in a region of granite rock. Four 

 parallel ridges begin on the rather steep southern slope of a hill and extend 

 about one-fourth of a mile southward to the base of the hill, where they 

 expand into low broad ridges and then appear to end in a dome of coarse 

 matter. To the south and east are some rather level till-covered fields, and 

 then the great clay-covered jjlain of Ja}^ and Chesterville, but I could trace 

 the glacial gravel no farther in that direction. The ridges are composed of 

 a mixture of gravel and 

 large stones of all sizes, 

 up to bowlders 3 feet in 

 diameter. The finer de- 

 tritus has been washed 

 away, but the stones are 

 hardl y more rounded 

 than those of the terminal 

 moraines of the local 



Fig. 22. — Stratification of lenticular gravel, a, a, very obscurely stratified 

 portions of kame, almost pellmeU in structure. 



Grilead and Shelburne. 

 The hillside systems usu- 

 ally become finer in composition at their south ends, where they terminate 

 in a sort of delta, but in this case the ridges are composed of coarse matter, 

 even to their extremities. The large size of the contained bowlders favors 

 the interpretation that these ridges were deposited beneath the ice. 



Another short system begins at the top of the hill which lies directly 

 south of Wilton Village, and extends for somewhat more than a mile south- 

 ward, into Jay, on the slopes of a long hill. Its course lies along the bot- 

 tom of a ravine 100 to 150 feet wide, which is bordered by steep banks of 

 till 10 to 30 feet high. The gravel forms a terrace lying against and upon 

 the till which forms the eastern bank of the ravine. On the west side the 

 bottom of the ravine is quite level and covered with soil finer in composi- 

 tion than the surface till of the surrounding country. It is either a very 

 clayey till or a sedimentary clay into which some tillstones have been 



