10 Captain Bayfield on the 
land on whichits rivers have their sources. This is much 
mnore extensive than the space at present occupied by its 
waters, 
The summit level is ih some parts close to the lake, whilst, 
in others, itis distant 50 or 70 miles. All that is known, 
(and it is known imperfectly,) on this subject, may be seen 
by areference to the latest maps. The height of the sources 
of such rivers as have been visited by Mr. Schoolcraft and 
Doctor Bigsby, has been estimated at from 505 to 614 
feet above Lake Superior. ‘The summits of the Hills are 
much higher, both on the north and south side of the lake . 
We measured some of them geometrically, and we are cer- 
tain that the highest are at least 1500 feet above the lake ; 
and consequently upwards of 2100 feet above the sea—an 
elevation insignificant when compared with other mountaia 
chains, but very striking when compared with the general 
level of the Canadas. 
It must be remembered, that it is not our intention to 
give a minute account of the rock formations of Lake Su- 
perior, for that has been already ably done, by that zealous 
and indefatigable geologist Doctor Bigsby: 
We shall endeavour to give a concise and general view 
of the several formations, shewing the extent they occupy, 
and the connexion of one side of the lake with the other 
by means of the islands, &c, We shall then notice those 
other parts of the subject which have been left undone by 
Doctor Bigsby, or which may have escaped his notice. 
10. For the sake of perspicuity alone, we shall divide the 
rocks of this lake into three orders. 
First. The inferior order. 
In this order we comprise various granites, which almost 
always contain more or less hornblende, and sometimes 
hornblende and felspar alone. 
In this last state we have seen it of Jarge crystals of both 
minerals 
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