258 Canadian Record of Science. 
under the lake; the frequent dip of the Huronian as well; 
the re-appearance of these strata on opposite sides in the 
western half of the lake; the regular order of succession of 
Keweenewan rocks, Huronian rocks and gneiss, granite and 
crystalline schists on all sides when proceeding inland from 
the coast, and the parallelism between the courses of the 
Keweenawan belts on the north and south shores, and of the 
coast line with these belts. 
At the eastern end of the lake, Cambrian rocks overlie 
the Keweenawan and Huronian, and now form the rim over 
which the lake waters flow in their course to Lake Huron. 
It is conceivable that the submerged channel fractured 
through these rocks here was, for ages, the outlet of Lake 
Superior into the Trenton, Hudson River, and later seas, 
and that even in more recent times it joined the submerged 
river channel in Lake Huron, coursing its way across the 
sandstones, limestones, and shales of the north peninsula of 
Michigan by a connecting valley which subsequent eleva- 
tion of the land has cut off. 
Now, all these facts appear to effectually dispel the idea 
that Lake Superior has a glacial origin. It is undoubtedly 
the oldest of the Great Lakes, and has preserved its present 
general contour through vast periods and for countless ages 
before the glacial period. That glaciers prevailed on the 
mountains and hills on its coasts during the ice age, polish- 
ing and grooving the rocks and dotting the united inland 
sea with ice and icebergs at certain seasons is probable, but 
they merely added to the effect of previous ages in toning 
down the rough edges of these mountains and hills, and 
scattering the loose material thus produced over the broad 
surface of the bottom. Great areas of this lake’s bottom 
around the Apostle Islands, the west side of the Keweenaw 
Peninsula, and within and on the west side of White 
Fish Bay, are surfaced with sand derived undoubtediy from 
the wear of the sandstones of these localities, whilst the 
general character of the bed. of the lake, especially in its 
most profound depths, is clay. 
Dr. Selwyn thinks that the geological features of the 
