594 GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS. 



Westfield River througli the wildest gorge in Massachusetts, deeply rock 

 cut, and abounding in very large potholes. One is inclined to surmise tliat 

 some portion of this erosion maj' date from Glacial or early post-Glacial 

 time. 



THE WESTHAMPTON LAKE. 



A much more extensive and interesting lake than the one mentioned 

 in the last pai-agi-aph occupied, at a much lower level, all the eastern pai-t of 

 Westhampton, about the headwater.s of the Mauhan River (g P, PI. XXXV, B). 

 It wound sinuously among great islands of granite, and extended south into 

 Easthampton, where it passed over a rocky sluiceway, which fixed its level, 

 into the headwaters of the South Branch of the Manlian. From Loudville 

 south into Southampton, around the east flank of Great Mountain, the sands 

 of this lake extend out freely into the Connecticut Valle}', without rocky 

 support on the east, and end in a terrace scarp, below which a broad slope 

 of till extends down 170 feet to the normal high terrace of the Connecticut 

 Lake. It is plain that the ice of the Connecticut River glacier furnished 

 the bank of the lake within these limits (b^). This was at its greatest 

 size. Subsequently it seems to have persisted, with diminished boundaries, 

 and to have received the overflow from the Williamsbui'g Lake, farther 

 north, when the ice had retreated north so as to set this free, and so to have 

 for a long time retained connection with a long and complicated series of 

 watercoui'ses, which extended back north to the ^•alleY of the Deerfield River, 

 and ceased to be occupied when this valley was abandoned by the ice. 



So soon, however, as the ice set free the gorge at LoudA-ille the lake 

 was tapped in its upper portion, and the greater part of its area is now di-ained 

 through this channel. Two watersheds, however, developed in this area, 

 one at the south, setting off" a portion to be di*ained by the South Branch of 

 the Manhan, and another at the north, which di-ains through the Roberts 

 Meadow Brook into the Mill Riv6r. These streams, especially the middle 

 ones, have cut a fine set of upland terraces in the sands of the ancient lake, 

 and as one sees these brooks leave their upland meadows and plunge into 

 deep gorges on their way to the vallej^ below, one is inclined to ask how far 

 these gorges were preexistent and how far they have been cut by the streams 

 since the time of the lake. In some cases the disappearance of the lake may 

 have been due to such a cutting down rather than to the removal of an ice 

 bander or the sudden sealing up of the sonrces of the glacial waters. I have 



