312 The American Geologist. May, 1895 
ward elevation.* The Nipissing beach declines westward 
from an altitude of 50 feet at Savilt Ste. Marie to 25 feet be- 
low the present lake level at Duluth. But if the lake became 
independent before the eastward uplift began, then at that 
time its level was 75 feet lower than now at Duluth ; for the 
last or lowest beach of the independent lake before the east- 
ward uplift was formed about 50 feet below the Nipissing 
beach at Sault Ste. Marie. I have called this the Sault beach. 
One of the pretty questions which this study suggests is the 
possible identity of this beach on the north shore. If differ- 
ential northward elevation went on within the Superior basin 
after independence and before the eastward uplift, this beach 
would be found more than 50 feet below the Nipissing beach 
on the north shore. Along that part where the Nipissing 
beach is more than 70 or 80 feet above the lake, we might 
therefore expect to find the Sault beach, provided it was 
strongly developed. An examination of Prof. Lawson's de- 
scriptions with reference to this subject shows the presence 
of a beach which may ultimately prove to be the one referred 
to. It is at least tolerably persistent and lies about 60 feet 
below the Nipissing beach. At series 36 and 38 its altitudes 
are 28.4 and 33.7 feet respectively, and at series 42, 43 and 44 
its hight is 33.5, 40 and 39.7 feet respectively. These locali- 
ties are nearly in a straight line parallel with the isobases. 
The identity of this beach is of course uncertain on this show- 
ing alone, but the suggestion may be worthy of future consid- 
eration. 
Professor Lawson concluded that there is little or no defor- 
mation of the lower shore lines. His conclusion, however, 
depended upon two things : first, on the fact that his tracing 
was not continuous; and second, on his method of correlation, 
in which he assumed horizontality on insufficient evidence. 
His descriptions, however, are so clear and detailed that I be- 
lieve the Nipissing beach is traceable by them with a fair de- 
gree of certainty. 
In one of his recent papers Mr. Upham says that he finds 
reasons which "justify to a remarkable degree Dr. Lawson's 
opinion that the ancient shore lines of lake Warren in the 
*This point is fully discussed in the paper on the second lake Algon- 
quin referred to above. 
