GLACIAL WATERS IN BLACK AND MOHAWK VALLEYS 17 



channels, from valley to valley, and parallel with the general land 

 slope, must occur over the west-facing and south-facing slope of 

 the high ground as far as to the Rome district. 



Deltas in Glenfield lake. During the previous stage a small 

 lake had been held in the valley of Deer river, along the summit 

 of the great ridge between the Black and Ontario valleys. The 

 escape of the Deer lake must have been westward through a summit 

 swamp, north of New Boston at about 1530 feet, into the ice- 

 border drainage noted above. One channel seems to lie through 

 Barnes Corners. When the ice barrier receded to the vicinity of 

 Harrisburg the Deer lake escaped eastward and so continued by a 

 series of small but distinct channels at falling levels until the Deer 

 lake was drained. These outlets of Deer lake built a delta of con- 

 spicuous size on the west shore of the Black waters near Harris- 

 burg, and five miles northwest of Lowville. Other deltas occur 

 where the Deer river dropped its detritus in the falling Glenfield 

 lake below High Falls and at Kings Falls. The reader should 

 observe that the Deer lake outlets are the only east-leading channels 

 on plate 4. 



FIFTH stage: lake IROQUOIS 



When the ice front receded from the promontory lying between 

 Watertown and Carthage the distinctive Black valley waters ceased 

 to exist and the Carthage district was occupied by the waters of the 

 great Lake Iroquois. The Iroquois beaches are found in conspicuous 

 form on the steep slope northeast of Watertown, at y;^;^ feet. East- 

 vvard toward Champion Huddle and Carthage the shore line features 

 are fragmentary, but the altitude is taken as 740 to 750 feet. The 

 plain of the Black river above Carthage is now 730 to 740 feet, 

 and the Iroquois waters at first probably extended some miles up 

 the valley, but soon filled with the river silt, becoming a swamp. 

 The real delta of the Black river in Lake Iroquois is the very ex- 

 tensive sand plain heading northwest of Carthage forming the " Pine 

 Plains," which extend to Black River, Felts Mills and Leraysville. 

 The head of the plain is about 735 feet, declining to 520 at 

 Leraysville. 



Until the quadrangle north of Carthage is mapped the Iroquois 

 features of the region can not be satisfactorily described. 



prewisconsin topography 

 The tract of country covered by the heavy channels in plate 4 

 exhibits many scarps, terraces and hollows which antedated the 

 river flow under discussion. Some of these are comparable to the 



