598 GEOLOGY OF OLD HAMPSHIEB COUNTY, MASS. 



The tributaries on the south side have for the most part cut their way 

 through heavy glacial lake deposits, and their facies is thus extremely dif- 

 ferent from the north-side tributaries, as the former are bordered in their 

 upper courses by broad, heavy deposits of high-level sands and gravels in 

 which they have cut their terraces, while on the north the streams come 

 down in narrow gorges, and only in Coleraine does one widen to form any 

 considerable meadow. This in part explains why Conway and Ashfield 

 are more flourishing villages than the northern tier of towns from Leyden 

 to Monroe. 



THE CONWAY LAKE. 



Just at the Conway station the train crosses at a dizzy height the South 

 River where it enters the Deerfield. The station is about at the level at 

 which the waters stood at their highest flood after they had obtained free pas- 

 sage to the Connecticut. The Deei"field now runs in its rocky bed nearly 200 

 feet below, and the road from the station toils up over heavy sands another 

 hundred feet to a broad, level area of sand, bounded on the south, east, and 

 north by the South and Deerfield rivers, which, when the ice obstruction 

 (b^^, PI. XXXV, A) below was removed, cut down through these sands into 

 the rock so quickly that they did not wear back at all into the sands. A 

 great triangle between the rivers, bounded on the west by the road from the 

 South River to the Deerfield, and a mile on a side, is occupied by this great 

 body of sands (gl^; in its eastern and larger part it is quite horizontal, at 

 about 460 feet above sea, while in its western part the sand rises nearly 100 

 feet higher and is covered by till, as if, at an earlier stage of the lake, the 

 waters had stood above this higher level and brought up the sands to that 

 level, and then oscillations of the ice brought in a covering of till over part 

 of the area and determined then or later a lower level for the lake, down to 

 which its sands were terraced. The area requires more study than I could 

 give it. The sands at this lower level are continuous as a broad band south, 

 up the valley of the South River, widening over the area of the village of 

 Conway and receiving there a body of sands which extend up the South 

 River through Burkville, in that part of its valley which runs northwest. 



The South River enters the town running east, and holds this direc- 

 tion a mile (the latter part is an empty valley); then it bends south a 

 mile to Conway, and in this part it was occupied by a glacial current which 

 moved south to meet at Conway village the current moving south up the 



