ioo ICE RECESSION IN NEW ENGLAND 



of the ice very likely corresponded to the readvance at Claremont 

 and Lake Winnepesaukee, N. H., which occurred about years 

 6200 to 6500. 



When the ice edge again withdrew, the outlet of the Great 

 Lakes was shifted for the second time to the Mohawk Valley, 

 and Lake Lundy came into existence (Taylor, 1913, p. 309; 

 I 9 I 5> P- 399 and 406 and PI. 19; Fairchild, 1909, PI. 40). The 

 exact position of the ice barrier of the lake is not known, but it 

 was between the Niagara escarpment and the present shore of 

 Lake Ontario. The beaches of the lake have only moderate 

 strength and indicate a transition stage. As the ice retired and 

 lower outlets were uncovered, the waters fell, so that those over 

 Lake Ontario became separated from those in the Erie basin. 

 In the Ontario basin the transition stages to Lake Iroquois under- 

 went a number of changes of level caused by slight retreats and 

 readvances of the ice front (Taylor, 1913, p. 310; 1915, p. 444). 

 Finally the waters fell, owing to the opening of a lower outlet at 

 Rome, and Lake Iroquois was established. This lake endured 

 for a relatively long time. When the ice front had receded to 

 the northern side of the Adirondacks, Lake Iroquois emptied into 

 Lake Champlain, and the Rome outlet was abandoned (Peet, 

 1904, p. 660). The lake level sank as the ice withdrew, and 

 finally the sea, entering the submerged St. Lawrence Valley, 

 changed the glacial lake into a marine gulf. 



Before the marine stage could come into existence the ice had 

 receded beyond the St. Lawrence River. The transition stages 

 preceding Lake Iroquois and the lake itself, therefore, must 

 correspond to the ice recession in northern New England and 

 southeastern Canada. The pre-Iroquois oscillations of the ice 

 border may correspond to the repeated readvances of the ice, 

 which, as a reconnaissance study of the clays seems to show, 

 occurred in the zone between St. Johnsbury and the Canadian 

 frontier. 



Problems To Be Studied 



This memoir only treats the main features of the recession of 

 the last ice sheet in New England, while the details and a great 



