342 FRA NK BURS LEY TA YL OR 



especially along the west slope of Hoosac mountain and on the 

 hills north of Williamstown. The latter, however, are very much 

 modified by the strong border drainage that was associated with 

 them. On this account they show a much greater proportion of 

 coarse sediment than usual and also a more varied topography. 



(4) Stoss moraines. — These are moraines that are banked up 

 on the stoss-side of hills or mountains which stood in sharp 

 re-entrant angles of the ice-front. They have the same general 

 character as the lateral moraines described above, and might 

 perhaps be included with them. Like them they are distinctly 

 submarginal and very smooth in expression and seldom well 

 developed. They differ, however, from the lateral moraines 

 somewhat in the manner of their occurrence and in their associa- 

 tions. Only a few good examples were seen, and none of these 

 appeared to have border drainage associated with them nor any 

 deposits of sand or gravel. The best example of this class was 

 found on the north slope of Miles mountain, a mile and a half 

 southwest of Ashley Falls. The north slope of this mountain is 

 covered with a heavy coating of bowldery till up to about 300 

 feet above the river, but here the till suddenly grows thin. 



All through the Berkshires the normal action of the glacier 

 on the steeper stoss-slopes of mountains was to rub them hard 

 and sweep them clean of all loose materials. Following this 

 rule, the steeper stoss-slopes of the mountains are usually bare 

 or only very thinly coated with drift. The drift sheet of the 

 valleys usually rises somewhat upon their lower flanks, but this 

 cannot be counted as a marginal deposit. However, where a 

 high stoss-slope which would normally be swept bare is found 

 to carry a heavy bank of bowldery till up to a certain height, 

 above which the hill is mostly bare, the explanation seems to be 

 that the bank of till was deposited just under the edge of the 

 ice when the ice-front rested there and was depositing, and hence 

 not sweeping heavily up the slope and over the hill. Stoss- 

 slopes are swept bare most effectively when situated under the 

 ice at some distance back from the edge and when the ice mass 

 is moving freely over the tops of the hills. On Day mountain,, 

 which rises south of Dalton, there is a similar deposit. 



