Correspondence. 
401 
cepting only the still higher shores of the Western Superior glacial lake, 
reaching from Duluth east to Marquette), and their eastern extension 
about the north part of lake Huron and of Georgian bay to lake Nipis- 
sing, are referable to Spencer’s lake Algonquin. On the other hand, I 
hold, with Dr. A. C. Lawson, that the high beaches around lake Supe¬ 
rior (excepting westward) belong to Spencer’s lake Warren; and I be¬ 
lieve that these shores are continuously traceable southward to the Ar- 
kona and Forest (or upper and lower Crittenden ) beaches of lake Warren 
in its earliest and most thoroughly explored portion, namely, in the lake 
Erie basin. 
Until the beaches thus differently correlated shall be traced continu¬ 
ously through the largely wooded country surrounding lake Huron, as I 
have continuously examined and mapped, with leveling, the beaches of 
lake Agassiz along more than a thousand miles, we cannot probably ap¬ 
peal to such demonstrative proof of either Mr. Taylor’s or my view as to 
admit no further possibility of doubt. Meanwhile, in support of my in¬ 
terpretation of the published data, we have fifteen, or more, distinct 
marginal moraines mapped by Leverett and others in Ohio, Indiana, 
and southern Michigan, while I have mapped twelve such moraines in 
Minnesota, the most northern of these, passing by the south side of 
Vermilion lake, being probably contemporaneous, or approximately so, 
with the maximum extent of the Western Superior glacial lake. The 
general northwest to southeast outline of the boundary of the ice-sheet 
during its retreat is thus very definitely ascertained, in parallelism with 
the farthest limit attained by the ice accumulation and outflow on the 
plains of North and South Dakota, Nebraska, and Kansas, during the 
maximum Kansan stage of the Glacial period. 
In the American Geologist for March, 1895 (vol. xv, pp. 162-179), 
Mr. Taylor argues that the northward differential uplift of these beaches 
and of the lake Superior and Huron basins mainly preceded their east¬ 
ward uplift; and this conclusion, with which (from other evidences) I 
concur, accords with the moraines in showing that the ice-sheet re¬ 
treated first from the region of the upper Laurentian lakes and later 
from the lake Ontario and Ottawa basins. As soon as the glacial reces¬ 
sion uncovered the land, it rose from its Late Glacial or Champlain de¬ 
pression . 
The Algonquin beach about the south part of lake Huron, as traced 
by Spencer, I cannot therefore correlate, until continuity shall be de¬ 
monstrated by continuous exploration and leveling, with the highest 
shore around the north part of this lake, on Mackinac island, and around 
the eastern two-thirds of lake Superior. That high water plane I refer to 
lake Warren, outflowing past Chicago to the Des Plaines, Illinois, and 
Mississippi rivers. When the glacial retreat subsequently opened an 
outlet from the Laurentian lake region past Rome to the Mohawk and 
Hudson, the ice-sheet still rested on the Ontarian and Lauren tide high¬ 
lands from near Toronto northward to the Ottawa basin and thence 
northeastward, as shown by the two glacial re-advances forming till de¬ 
posits above the stratified and fossiliferous interglacial beds of Toronto 
