Niiiissing Beach on the JST. Superior Shore. — Taylor. 307 
lake." Behind the upper beach there is a broad expanse of marshy 
ground forming a lagoon. 
Series 16. Double Bay. From the modern sea-cliff a terrace reaches 
back a quarter of a mile, at its rear 32 feet above the lake. 
The Nipissing plane produced to this coast from the south- 
east, as shown in the map accompanying the paper on the 
second lake Algonquin, would strike between 25 and 30 feet 
above the lake at Grand Marais. This is in very close agree- 
ment with the strong continuous beach of 29.1 feet at that 
place and eastward to a point below Brule river, a distance of 
10 miles or more. "Westward from Grand Marais the terrace 
of 27.2 feet at Good Harbor bay, and that of 17.8 feet east of 
Poplar river, and that of 21.7 feet at Poplar river, 20 miles 
west of Grand Marais, are in all probability the same beach. 
So far as I am able to judge from Prof. Lawson's descriptions, 
this beach seems to correspond very closely in all respects 
with the Nipissing beach of the south shore. Its identity as 
a part of this beach may be fairly assumed for the present. 
Westward from Poplar river it does not appear to be recog- 
nizable, but by calculation the Nipissing beach should pass 
under the lake about at Beaver Bay, and 25 feet below it at 
Duluth. The boulder beach ridge of 38.6 feet at Horseshoe 
bay farther east is undoubtedly the same shore line, its 
greater hight being due to the fact that it is a beach ridge, 
while toward the west it is a cut terrace. Measurements of 
the same shore line often vary seven or eight feet, sometimes 
more, from this cause. Prof. Lawson's measurements are very 
precise, even to tenths of a foot. But it is not intended to 
convey the idea that the former water level can be so accu- 
rately determined. It can seldom be made out so closely as 
not to leave a possible error of at least one to two feet. The 
wide terrace of 32 feet at Double bay is probably the same 
beach as that mentioned above, although it is six and a half 
feet lower. This gives us a stretch of abandoned beach along 
about 40 miles of the coast and identified with fair probabil- 
ity as the Nipissing beach. The distance from Poplar river 
to Horseshoe bay on the line of maximum rise for the Nipis- 
sing plane is about 25 miles and the rise is from 21.7 feet at 
Poplar river to 38.6 feet at Horseshoe bay, making a rate of a 
little more than seven inches per mile, which is about one 
