THE HADLEY LAKE BOTTOM. 673 



especially opposite the entrance of streams. At times, however, especially 

 where the water stood against older sand deposits and where there was little 

 cmTent, a very gradual slope goes down to the lake bottom from the old water 

 surface notched in these sands, and no sharp line of demarcation exists. 



In the northern part of the Montague Lake the filling was nearly 

 complete and the lake bottom is at a high level, and the deepest portion of 

 it, the thread of the old stream, has been removed by the later erosion of the 

 river. Beers plain, in Northfield, is the principal area of the old lake bot- 

 tom (or here, rather, river bottom) in this northern portion It is separated 

 by the great delta of Millers River from the deep, unfilled depi'ession in 

 which lies the village of Montague. The latter is a deep hollow, sur- 

 rounded on three sides by rock, while on the north the great scarp of tlie 

 above delta forms its boundary. The many streams which join and run 

 across the bottom of this small basin have obliterated most of the old sur- 

 face of the lake bottom. 



There is a certain curious parallelism in many orographic features 

 between this basin and the much larger Amherst basin. The village of 

 Plain^■ille, in this latter basin, has the same relative position as Montague 

 village. To the west of each rises a great hill, which stood as an island in 

 the lake, and around the north side of wliich runs a stream draining the 

 basin. To the southeast a sharp notch between the Trias and the crystal- 

 line rocks passes into the next basin south. To the south the Connecticut 

 cuts tlu-ough the Trias in a naiTow gorge, and to the southwest, in each case 

 extends the broad lateral valley once occupied by the flooded river. 



THE HADLEY LAKE BOTTOM. 



Here, as compared with the preceding liasin, the conditions are wholly 

 reversed, and the space occupied by the high terrace is, especially along the 

 east side of the basin, very small as compared with that covered by the lake 

 bottom. The real disproportion will appear more clearly if one imagines 

 the color of the lake bottom (1 b t) on the map extended across the succes- 

 sion of shades (t 1-4) which represent the later erosion terraces cut in this 

 lake bottom by the Connecticut and its tributaries. This disproportion is 

 as striking in a vertical as in a horizontal sense, since the imdulating lake 

 bottom is over liroad areas raised only a few feet above the present flood 

 plain of the Connecticut. 

 MON xxix 43 



