DRUMLINS OF CENTRAL WESTERN NEW YORK 43 1 



district of low ground northeast and east of Syracuse (over Oneida 

 lake, Canastota, Oneida and eastward) we have an illustration of 

 nonmotion of the ground-contact ice. The almost bare hills of soft 

 Vernon shales in the region of Canastota have not been subjected to 

 the rubbing action of the ice from any direction. In form these clay 

 hills closely resemble moraine drift, and with their slight veneer of 

 glacial rubbish would at first be mistaken for moraine by even the 

 experienced geologist. This surface would have been sensitive to 

 any ice movement, the absence of which is explained as follows: 

 While the ice sheet was thick the flow was from the northward and 

 the ground-contact ice in this district, lying in the broad depression 

 between the Adirondack'massive on the north and the high plateau 

 on the south, was quiescent. With the waning of the ice sheet it 

 disappeared from the high ground to the north so that the stagnant 

 mass resting on the Canastota-Oneida district was not subjected to 

 any push from the northward. ' During the closing or drumlin-mak- 

 ing phase of the ice work in the Ontario basin the radially spreading 

 ice of the Ontarian mass did not reach this district. In brief, the 

 ground-contact ice over the Canastota-Oneida district, although occu- 

 pying a low tract on the edge of the drumlin area, did not at any 

 time receive horizontal impulse but was deserted and allowed to 

 quietly melt away, or perhaps to be lifted and rafted off in the 

 glacial lake waters which fronted the glacier. The extreme reach 

 of the drumlin-forming- activity in the Syracuse district was in the 

 form of a tongue or wedge of moving ice which was thrust south- 

 eastward along the Onondaga lake depression and over the site of 

 Syracuse, ending a few miles southeast of the city; and affecting only 

 the higher ground, or the summits of the island masses. 



Origin. It is certain that the - New York drumlins were con- 

 structed or built up by a plastering-on process. The ice did not 

 drop its drift burden in the depressions or low places but plastered 

 it on the obstructions. The plastic and adhesive character of the 

 shale-derived drift of central New York is probably one factor 

 accounting for the great number, hight and shape of the drumlins 

 of that district. 



The rocdrumlins, or shale hills with the peculiar drumlin form, 

 being shaped by a moderate amount of erosion of the soft rock 

 might suggest, at first thought, that erosion was the main factor in 

 drumlin formation. Possibly it may be in some regions; but vig- 



