THE WILLIAMSBURG LAKE. 595 



for the most })art used the latter as a working- hypotliesis. In several 

 jjlaces, as in the Coinieeticut gorge above the mouth of Millers River, much 

 erosion of the rocks has taken place since the time of the lakes. 



THE WILLIAMSBURG LAKE. 



The Mill River at Williamsburg village has cut its ten-aces in a great 

 body of coarse sand, whose flat surface is 33 feet above the stream. TTntil 

 the ice had so far melted back that the Deerfield River was open, the over- 

 flow of the Ashfield and Conway lakes, described below, reached this lake 

 by way of Mill River and Joe Wright's brook, respectively, though, as the 

 waters left in their passage through these narrow gorges no deposits to attest 

 their former presence, there is on the map an apparent break in the conti- 

 nuity of the deposits between them, of considerable extent in the case of Mill 

 River. The proof of this former continuity is given in the description of 

 the other lakes. 



The sands of this lake (g \\ PI. XXXV, A) can be followed down South 

 street to the south line of the town, where they divide, one band going- 

 south to join the Westhampton Lake, the other southeast in Northampton to 

 where it widened into the Roberts Meadow Lake, whose waters regained the 

 valley of the Mill River at Leeds, and also passed south into the A-alley of 

 the Connecticut, down the deep, empty gorge west of Roberts Hills. This 

 gorge has, as in so many other cases, a brook heading in its l)ottom and 

 running north, and another brook heading farther south and running south, 

 while the gorge is continuous and of uniform size and depth from the 

 Roberts Meadow basin to the open Connecticut Valley. It seems to me a 

 product of subglacial drainage or of the obstructed post-Glacial drainag-e I 

 am here tracing. 



THE BEAVER BROOK LAKE ABOVE LEEDS. 



This small lake lay encircled by high hills in the east part of Williams- 

 bm-g and was drained by a deep gorge through which the brook above 

 named now flows to join the Mill River at Leeds. 



THE DEERFIELD RIVER LAKES. 



The obstructed drainage south of the Deertield River (PI. XXXV, A) 

 was most curious and complex. That it was, mutatis mutandis, the counter- 

 part of the drainage south from the Millers River (p. 573) comes out very 

 clearly. The ice melted back across the high, irregular area south of the 



