Geology of Lake Superior. 19 
on the south-east coast of that lake: also at the south point 
of Sagana bay. 
At the Falls of Niagara and below them, it supports fetid 
limestone similar to some of the limestone of the Manitoulins, 
also at the Oswego and Genessee rivers on lake Ontario. 
Tn opposition to this supposition, however, it must be re« 
marked, that we have often seen the junction of the limestone 
of Lake Huron with the granite, gneiss, and quartz rock, 
and in every instance it laid immediately upon them, without 
any rock intervening. 
We are of opinion that it requires much more elaborate in- 
vestigation than has yet been bestowed to render jit certain 
that the sandstone of Lake Superior, and thatof the exten- 
sive tracts of country which we have mentioned are the same 
formation, for the sandstone of the northern parts of New- 
York, contain gypsum and rock salt, and would therefore ac- 
cording to the generally received opinions of geologists, belong 
toa younger order of rocks, On the other hand, great quanti- 
ties of gypsum are found on the St. Martins Islands near 
Michilimakinac, in the immediate vicinity of which large slabs 
of sandstone occur, so little injured, that they must be very 
near their parent rock. 
15. Having made all the observations which appear to us 
likely to throw any light upon this subject, we proceed to give 
our reasons for terming the sandstone of Lake Superior the 
old red. These are, its position immediately on the granite, 
its structure and component parts. The two last have been 
fully described by Doctor Bigsby, it will therefore only be 
necessary to observe, that it is principally composed of fine 
graioes of quartz aod small fragments of felspar, containing 
disintegrated particles of all the older rocks of the lake, When 
it is so coarse as to become a conglomerate, which very fre- 
quently is the case, it contains fragments of the trap or overly. 
ing rocks, as well as of the inferior order. It.is in some districts 
C2 simply 
