564 GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS. 



basin, in Greenfield, the ice was thrust into the valley and lingered there 

 until the period of flooding had passed its climax and the waters had begun 

 to recede. 



Finallv, from the shoreward (western) edge of the high sand terrace 

 on the western side one passes immediately onto the bare ledges of rock 

 or onto the coarse till of the uplands, and not, as one often may on the 

 east side, onto sands which stretch continuously many hundred feet above 

 the level of the former Connecticut Lake. Only in exceptional cases, as 

 noted above, where a valley dips northward, has the ice clogged its mouth 

 and aided in the accumulation of glacial lake deposits on this side also. 

 These are here of limited extent and importance. 



On the east side of the great longitudinal valley of the Connecticut 

 the land rises rapidly to a height of 800 or 900 feet and then slowly 

 merges into the plateau of Worcester County. It is a hilly country, and as 

 the rocks strike north and south, it is cut into a series of jiarallel ranges by 

 north-south vallevs; onlv two transverse valleys, occu])ied by the Chicopee 

 and Millers rivers, cut back bevond the front range of hills. The tribu- 

 taries of both these extend back far l)e3"ond the limits of the county and 

 branch out over the western half of the Worcester County hig-hland. 

 From the southern line to the middle of the State, in the latitude of 

 Amherst, the front range is broken ouly by the long gorge of the Chicopee. 



Pelham Brook in Amherst and Locks Pond Brook in Montague break 

 through the front range, but no other stream does this except Millers River, 

 alreadv mentioned, before we reach the north line of the State. Just over 

 this line Perchee Brook sets back through the front range and drains the 

 liroad vallev east of it in Warwick. 



The order of the formation of these lakes must have been from south- 

 east to northwest, as already stated, and we have thus to discuss the deposits 

 found in the southeast portion of the area first, and then 2)roceed north and 

 west. Where the Chicopee River extends eastward bevond the limits of 

 the county the longitudinal vallevs are less pronounced, the whole area is 

 elevated and flat, and the conditions were less favorable for the formation 

 of glacial lakes, and for some distance eastward no trace of them is to be 

 found, so far as I have seen. It is a broad, high area of undisturbed till, 

 not covered by any later deposit. Faither east distinct and extensive kame 

 ridges run north aud south across the area and seem to replace the lake 

 sands discussed below. 



