Geology of Lake Superior. et 
from gales of wind, or any other cause, could form the three 
or four most elevated of these ridges, nor could the ice pro- 
duce this effect. It has evidently been done long since, as is 
proved by the trees and shrubs which we have mentioned. 
6. There is no regularly periodical rising or falling of 
the lakes, as has been asserted, whether it be, froin the in- 
fluence of the moon, or any other. They rise and fall ree 
gularly, from accidental causes, such as that of a very severe 
winter without the usual thaws. ‘The springs are then locked 
up all winter, and the whole accumulated snow remains, un- 
til the spring of the year, when the weather becoming sud- 
denly warm dissolves it all at once. Hence it will generally 
be found, that after a very severe winter, the waters of the 
Jakes will be much higher than at other times. 
Heavy gales of wind also rise the waters, in the upper parts 
of the lakes from which they blow, and also cause currents 
in various directions. The rise of water however, in any part 
of the Lakes Superior and Huron, from this or any other 
cause, neverexceeds afew feet. When Doctor Bigsby asserts 
that autumnal gales will raise the water 20 or 30 feet, at 
Michipicoten, Gargantua, or Otters Head,* we perceive, 
that he has been deceived, by the hyperbolical mode of speak- 
ing of the fur (raders, ‘The same thing was told to us at the 
first of these places, but upon cross questioning the narrator 
of this story, we found that he only meant the spray of the 
surf. But we have been encamped on the shores of this 
Lake, at all seasons, and have seen some as heavy gales as 
ever blew there, which rose the water only a few feet. 
7. Whether a gradual diminution of the waters of this 
lake be at present going on is a point upon which no one 
is at present qualified to give an opiuion. For no observa- 
tions have been made or recorded to ascertain this interest. 
ing 
* Journal of Science, Literature, and Arts, No. XXXV, pave 
8, Dr, Bigsby on the Geology and Geography of Lake Superior, 
