THE OONWAY LAKE. 599 



valley of South River from tlie station. It seems to me probable tliat when 

 the ice first melted out of the great triangle at the station it still filled the 

 deep valley at and north of Conway village, while the Connecticut glacier 

 dammed up the mouth of the Deerfield and held the waters up to a height of 

 jierhaps 550 feet. After this the ice abandoned the South River Valley as 

 far west as the first bend in the river mentioned, above a mile from the west 

 line of the town. Then the waters, passing down the two lobes of this val- 

 ley and joining where the ^•illage now is, filled the valley to the height of 

 the gx'ound where the academy stands, and all the area to the south (now 

 reemptied by erosion), and escaped southwardly by the narrow pass by 

 which the main road goes south into Whately. As one goes south from 

 Conway he sees the broad, level gravel plains, 100 feet above the village, 

 which surround the town and extend south, passing continuously and at the 

 same level into the flat, plainly waterworn bottom of the narrow canyon, 

 and it is clear that this canyon has fixed the level of the lake. We follow 

 this watercourse southward easily and find it expanding into a lake around 

 the headwaters of Roaring Brook, and branching to follow this valley 

 down a mile southeast, ending abru])tl}^ The Connecticut glacier would 

 seem to have still clogged this vallev, and I have so represented it (b", PI. 

 XXXV, A). The main stream channel contirmes south into Whately and, 

 reaching the headwaters of West Brook, widens considerably and then con- 

 tracts at West Whately, where it bends sharply west into Williamsburg. It 

 is quite remarkable that it should thus bend, for the open West Brook Val- 

 ley turns here toward the east, and, after 50 rods of empty valley way, 

 exjjands on either side of the brook's bed ; and 200 feet below the sands of 

 the above watercourse a great area of hea^^y sorted gravels begins, which 

 continues southeast with the brook for a mile, widening to above a half 

 mile and ending abruptlv with a great scarp which overlooks a broad, sand- 

 less valley. Remnants of ice on the east of the main-valley watercourse 

 must have kept it out of the Roaring Brook Valley, as above, and also 

 deflected it at West Whately (b'^), and the ice, being breached, let the 

 waters tlu-ough in a flood, which di'opped this great volume of gravel as 

 it expanded into the open valley after the manner discussed under the 

 section concerning high-level deltas (p. 605), or the ice may have erected 

 a later ban-ier lower down the valley (b'"). In Williamsburg the stream 

 expanded into another basin, now a broad sand plain, and escaped south 



