20 A. P. BRIGHAM — GLACIAL FLOOD DEPOSITS. 



ther north and around the end of the range that comes up between Oris- 

 kany Falls and Waterville the kame merges imperceptibly with the 

 ground moraine rising above it. 



Numerous sections show the usual discordant structure. Sometimes 

 no trace of bedding appears, but the material is well water-worn, and till 

 sections or scratched fragments are almost never found in this and the 

 kame fillings of adjoining valleys except near the junction of the kame 

 with the ground moraine of the hill slopes. The inclination of beds is 

 commonly to the southwest, often at a high angle. The material for the 

 most part has been carried from two to four miles from its sources, sev- 

 eral Paleozoic outcrops being here crossed in rapid succession. 



Dr Harris believes that the kames were formed at the edge of the ice, 

 in a foot-lake which lay north of the col. I am led to question this as 

 the precise mode of their origin. No doubt sluggish streams and irregu- 

 lar, temporary lakelets at the margin often received material which 

 helped to make up the mass ; but if a foot-lake of considerable propor- 

 tions existed it was probably after the construction of the kames ; nor 

 does it seem possible that it could have discharged copiously or long at 

 Bouckville, since the frail hills of kame upon whose flanks its waters 

 must have risen do not afford evidence of its presence. Professor Cham- 

 berlin remarks that kames are associated with vigorous ice-action, and 

 that hence they represent chiefly marginal glacio-fluvial deposition.* 

 The case in hand is a particularly good illustration. The kames were 

 formed at the border of a massive tongue of ice, and continually grew 

 inward and northward, taking possession of the valley as the glacier va- 

 cated it. That the ice, though slowly receding, should still at times be 

 active is evident when we remember the great depth and breadth of the 

 Mohawk Valley depression. With a surface slope of but 30 feet to the 

 mile; the ice would have been 1,400 feet thick over the site of Utica 

 while the kames were forming at Oriskany Falls. Owing to the near- 

 ness of the Adirondacks, the slope and consequent depth of the ice may 

 have been greater. In any case both the topography of the region and 

 the great bulk of the kames show that the ice crowded down from the 

 heights, filling the Mohawk basin to its rim about Oriskany Falls, and 

 maintained a fluctuating margin there for a long period of time. It is 

 quite possible that this single kame area contains as much rock debris 

 as issues from the mouth of the Mississippi in a period of ten years. 



Areas about Hamilton. — About three miles north of Hamilton, border- 

 ing the west side of the valley for a mile and a half, is a minor belt of 

 kames of moderate relief, flanked by glacial ponds and a large swamp 

 on the east and succeeded by a terrace southward. An ice-tongue which 



* The Great Ice Age. Geikie. Glacial Phenomena of North America, p. 746. . 



