THE GORGE TERRACE OF DRY BROOK HILL. 601 



In connection witli the second ])oint, we may call to mind (see p. 718) 

 that arctic plants are found in the clays of the Hadley Lake to their top; 

 this indicates a cold climate at an even later time than the one contemplated 

 here, which would permit the ice to remain buried ;dmost indetinitely. 



As to the tirst point, the area covered by the gravels in question, except 

 toward the west, be}'Oud Moody Comers, was left filled nearly to the 

 present level by the ice, and a great body of gravel was swept into this area 

 through the notches of the Holyoke range, and last of all, the last floods 

 passing through the Belchertown notch spread these gravels and carried 

 them south and blended them with the finer contributions of the Chicopee 

 River. It does not seem improbable that floods rising 40 feet above the level 

 of the confluent deltas of the Hadley Lake may have occun-ed many times, 

 even after the ice had retreated wholly from this lake basin; but it seems 

 more probable that the southern basin was set free from the ice so long 

 befiire the northern that the operations here under consideration had been 

 in the main completed before the ice finally retreated from the greater 

 portion of the Hadley basin. 1 may refer, also, to the proofs of a readvance 

 of the ice in this basin given below. 



A further consideration, to which we now turn, will show that the floods 

 through the Belchertown notch continued until after the ice had set free the 

 Holyoke notch, through which the river now runs. 



THE " GORGE TERRACE " OF DRY BROOK HILL, SOUTH OF HOLYOKE NOTCH, IN 

 THE NORTH PART OF SOUTH HADLEY. 



•The terrace of Dry Brook Hill, in South Hadley, is the most remark- 

 able terrace in the valley, and was the type of a class in President Hitch- 

 cock's classification of terraces.^ If the deposits removed by the erosion of 

 the brooks in the north of Granby and South Hadley be restored in imagi- 

 nation, what seems an old river com'se may be followed tlu'ough the Belcher- 

 town notch and along south of the Holyoke range — and it was held to be 

 an old river bed by President Hitchcock^ — until just south of the Mountain 

 House it bends south on a great drumlin southwest of Moody Comers and 

 then runs south as a well-defined river chaimel, skii-ting this hill on the east 

 and bounded on the west by the marked construction escarpment of a long 

 flat-topped hill of coarse stratified sand, the Dry Brook Hill, which, abutting 



' Surface Geology, p. 5. 



"' fteniinisfeuces of Amlierst College, p. 279, ami map. 



