398 The American Geologist. June, 1895 
lakes Iroquois and Hudson-Champlain thus merged in tlic glacial lake 
Si. Lawrence, which had a level about 250 feet below lake Iroquois and 
about 50 feet above the sea. 
7. Rapid melting of the border of the ice-sheet by the laving action of 
the lake St. Lawrence on the west and of the sea in the gulf of St. Law- 
rence on the east, finally cut through the ice-barrier, permitting the sea 
to come into the moderately depressed St. Lawrence, Ottawa and Cham- 
plain valleys, its southwestern limit being at the Thousand Islands, be- 
low the mouth of lake Ontario. 
Prof. C. H. Hitchcock, in the May number of the American Geolo- 
gist (pages 330-o35), cites abundant proofs of the transportation of drift 
from northwest to southeast across the highest mountains of New En- 
gland, which could have resulted only from the accumulation of the 
ice-sheet so thick as to fill the St. Lawrence valley and to have greater 
altitvide there and on the Laurentide highlands than on the mountain 
region south of the St. Lawrence. Eastward the ice had a lobate bor- 
der, with one lobe covering New Brunswick and Nova Scotia, while an- 
other extended from Labrador southeasterly over Newfoundland to the 
Grand Bank. An intervening tract, reaching northwesterly into the 
ice-sheet at least to the Magdalen islands, was exempted from glacia- 
tion.* 
Rain storms, sweeping northeasterly as now over the same region, 
melted away the southwestern border of the ice-sheet and caused it to 
recede chiefly from southwest to northeast; but farther eastward, when 
the storms within a half day, more or less, had advanced to distances 
of 100 to 200 m-iles upon the ice-sh<^et, their precipitation was doubtless 
changed to snow, causing the ice there to increase in thickness, and 
transferring the summit of the ice covering the St. Lawrence valley 
gradually farther and farther to the northeast. It seems thus very 
|)robable that the ice ma3' have remained latest as a barrier across this 
valley even as far northeastward as Metis, nearly 200 miles below Que- 
bec, which I think to be indicated by the glacial strite as these are de- 
scribed b}' Mr. Robert Chalmers. f The same predominairtly southwest- 
ward striation extends thence along the St. Lawrence \'alley, lakes On- 
tario and Erie, and onward to southern Illinois. Throughout this 
distance of more than 1,200 miles the glacial recession, as shown by the 
striae, was from southwest to northeast, and the barrier of ice holding 
the Laurentian glacial lakes was melted back from Chicago to Quebec, 
or perhaps even to the lower part of the present St. I^awrence estuary, 
previous to any opportunity for the sea to come into the valley. 
More than twenty years ago, Profs. N. H. Winchelland J. S. Newber- 
ry referred the Late Glacial submergence in the basins of the Red 
liver of the North and the river St. Lawrence to lakes held by the de- 
jiarting ice-sheet. Their opinion is well sustained, as tlie i^resent writer 
believes, b}' the observations which have since been gathered in more 
*Geologiral Survey of Canada, Report of Progress for 1879-80, Part G. American 
Geologist, vol. xv. pp. 198, 203, March, 189^ 
tAni. Journal of Science, III, vol. xlix, pp. 273-27?, April, 1895. 
