Geology of Lake Superior. G 
forms the northern coast of Lake Huron, passes close to 
the northward of Lake Simcoe, is met with in ascending all 
the streams tributary to the Rice Lakes, and doubtless cros- 
ses the Ottawa River, at some point above Lake Chat. It 
is met with in ascending all the rivers which enter the St. 
Lawrence from the north, approaches close to that river at 
Cape Tourmente below Quebec, whence it continues in a 
north-easterly direction to the coast of Labrador. A spur 
from this great chain, there is little doubt, crosses the St.Law- 
rence at the Thousand Islands. To the north-west, sienitic 
granite supporting slate always highly inclined, some- 
times vertical, and having an east north east direction, 
has been traced as far as Lake Winnipec. The extent 
westward and south westward is not so well known. It 
is however certain, that it forms the table land full of the 
small lakes in which the Mississippi, St. Lawrence, and 
the rivers which run into Hudson’s Bay have their sources : 
and it is a singular fact, that these are so nearly on a level, 
that canoes, in very wet seasons, have passed from one to 
the other. Either this ridge, or another in connexion with 
it, curves round the sources of the St. Lawrence,* whence 
it proceeds eastward, (in a curve to the southward,) to Poiat 
Iroquois, which, together with Gros Cap, form the entrance 
of Lake Superior. ‘These opposite headlands, about 4 miles 
apart, form the gorge of its geological basin: and here it is 
that the barrier appears to have given way, and allowed a free 
passage for its waters to the Atlantic. 
These southern highlands separate the rivers which ran 
into Lake Superior, from those which are tributary to the 
Mississippi and Lake Michigan. ‘The Basin of Lake Superior, 
we consider to be bounded by the summit level or height of 
land 
* It will be perceived that we speak of the sources of the ri. 
ver St. Louis, as being also those of the St. Lawrence. We con- 
sider the St. Lawrence as running through the lakes to the sea, 
and the St. Louis, St. Mary’s, St. Clair, Detroit, and Niagara 
as merely local names for = parts of the same river. 
