366 Jhe Aiiierican Geologist. May, isos 
and the width of outcrop of the ore belt is usually a half mile to one 
mile and probably nowhere exceeds two miles, while the known length 
of outcrop in Minnesota is about 145 miles, from the Mississippi river 
at Pokegama falls east-northeast to the Canadian boundary at the west 
end of Gunflint lake. 
Slietch of Lhc CoasUd Topography of the North Side of Lake Superior 
with special reference to the abandoned Strands of Lake Warren. By 
Andrew C. Lawson, pp. 181-289,with 6 plates and 15 figures in the text. 
(Twentieth Annual Report, Geol. Survey of Minnesota.) An abstract of 
this paper, as given in the announcements of the Ottawa meeting of the 
Geological Society, has already appeared in this volume of the Geologist 
(March, pp. 177, 178), with citations of the opinions held on this subject 
by G. K. Gilbert and Warren Upham, who differ from Dr. Lawson and 
ascribe the formerly higher levels of lake Superior, as of the other 
Laurentian lakes, to the barrier of the waning ice-sheet. Continuous 
levelling along any of the shore lines of this ruggedly hilly and forest- 
covered coast of lake Superior has been impracticable,but the altitudes 
of the old shores liave been determined by levelling at forty-eight places 
from the west end of the lake at Duhith to its southeastern angle and 
outlet at the Sault Ste. Marie. In the vicinity of Duluth the highest 
shore is 535 feet above lake Superior, or 1137 feet above the sea; and 
the highest shore anywhere discovered is on Mt. Josephine, near Grand 
Portage, about 140 miles east-northeast from Duluth, having an altitude 
of 607 feet above the lake. At Jackfish bay, again about 140 miles far- 
ther east-northeast, and somewhat east from the middle of the north 
coast, nineteen shore lines were identified, the highest being 418 feet 
above the lake; and at Sault Ste. Marie the highest one of eight shores 
observed is at 414 feet. In total, at the forty-eight localities where Dr. 
Lawson examined tliis northern and eastern shore of the lake, he recog- 
nizes, as he believes, thirty-three distinct former lake levels shown by 
deltas, terraces, and beach ridges, their average vertical distance apart 
being therefore about 18 feet. Where the highest beach was found, on 
Mt. Josephine, seven of these old shores are discernible, being in descend- 
ing order at 607,587,509, 313, 226, 43, and 20 feet above the lake. Where 
the greatest number for any single locality was found, at Jacklish bay, 
their hights are 418, .391, 367, 317, 259, 238,228,176,158,136,128,119,103,85, 
57,46,33, 19,and 10 feet; and at the Sault Ste. Marie, 414,365,311,224,208, 
174, 150, and 49 feet. 
Dr. Lawson thinks that this ancient lake, which was named Lake War- 
ren by Prof. J.W. Spencer, was not held in by the retreating ice-sheet 
but by land barriers, the country on the south and east having been 
relatively higher than now, and that the differential subsidence of the 
land there and contemporaneous uplifting of the country about Hudson 
bay went forward without disturbance of the horizontality of the old 
shore lines north and east of lake Superior. On tlie west, however, it 
has been ascertained by Upham for the area of the glacial lal<e Agassiz, 
in the basin of the Red river and of lake Winnipeg, that it experienced a 
differential uplift increasing about one foot to the mile from south to 
north during the departure of the ice-sheet; and on the east Leverett has 
