l6 NEW YORK STATE MUSEUM 



FOURTH stage: GLENFIELD lake; COPENHAGEN-CHAMPION outlets 



The remarkable series of west-leading channels shown in plate 4 

 are the outlets of this water. 



This lake did not have a permanent level but a series of falling 

 levels as new outlets were opened on the north-facing slopes south- 

 west of Carthage. The primitive and highest level was something 

 over 1200 feet, the present altitude of the bottom of the highest 

 channel, a mile northwest of Copenhagen. The lowest level was a 

 blending into the waters of Lake Iroquois at about 740 feet. The 

 lowest scourways seem to lie through West Carthage, a well-defined 

 channel west of the village being 760 feet. 



At the beginning of this stage the waters extended up the valley 

 to Boonville, but the area diminished as the surface fell by the 

 opening of successively lower outlets until only the lower or northern 

 part of the valley was flooded, probably only the stretch from 

 Carthage to Glenfield. This stage is called the Glenfield, as that 

 village is the most northerly in the axis of the valley. 



The northern part of the eastern shore of the lake is on territory 

 not yet mapped, being the quadrangle east of the Carthage and 

 north of the Port Leyden (Lowville sheet). 



The curving course of the outlet channels shows how the ice 

 front curved about the higher ground and deployed on the low 

 ground, thus forcing the drainage against the convex slope. The 

 earliest flow must have passed along the ice front east of Adams 

 and finally reached the primitive Iroquois waters farther south, 

 perhaps at Sand Bank or Williamstown, or possibly as far as Cam- 

 den. All the subsequent drainage found its base level in Lake Iro- 

 quois at Adams, where an extensive delta was built, with altitude 

 620 to 630 feet and fronted by the Iroquois beach. The higher 

 channels were cut in Lorraine shales, the lower in limestones. 



When the ice front lay higher on the land slope there must have 

 been a similar drainage past the ice margin of the local waters and 

 such channels of the earlier time are indicated on the map, east 

 and southeast of Adams, in the towns of Rodman and Lorraine, 

 lying along the general slope with a southward direction. This 

 local drainage probably ultimately reached the early Iroquois farther 

 south ; but the local drainage of a still earlier time must have fol- 

 lowed along the ice margin until it reached the Mohawk waters in 

 the vicinity of Rome (see page 34). No attempt is here made to 

 fully map the high-level ice-border drainage, it being represented 

 on plate 4 only where casually found. However, the cross-ridge 



