N. W. Portion of Lake Huron. 257 
I believe (together with Dr. Mitchill of New-York) that 
it has been formerly salt, and that in the course e of time it 
has been diluted b rivers, rains, snow, and dews: a ~~ 
stant drain materially assisting. ‘The sturgeon, a sea fish, i 
frequent in this lake and in great perfection. The falls of Ni- 
agara prevent their access from the sea. The very immen- 
sity of the flood which has buried a continent, identifies it 
with the ocean. But I need not multiply proofs after Dr. 
Mitchill’s powerful sepa of evidences 
Many of the facts just stated, shew that the waters of Lake 
Huron | have been i in “much greater quantity than at present: 
marshy alluvions, and the exten- 
sive collections of sand around the bases of recipices, and 
on the sides of heights. Ancient beaches are not uncom- 
mon at some distance from the water, as on) 
Manitou. It is likewise evinced by the belts of rolled mass 
- es which gird one slope, and even mark the successive 
retreats of the la 
The dense spdecisicls which covers the islands and envi- 
rons of Lake Huron, restricts our geological inquiries in a 
great measure to the immediate edge of the water; a nar- 
row border Panos the nature and stratification of the rock 
are disguised by multitade of causes. 
The rocks of ais districts embraced in the tour of 1820. 
belong to the transition and secondary classes of Werner. 
he transition formation occupies the north shore of the 
lake and some of its subordinate islets, from lon. 83° 42! to 
the foot of Lake George. From the small portion submit- 
ted to examination, it is difficult to detect their relation with 
the rocks around them, and even their comparative ages I 
was unable to assign positively, from their never over-lying 
each other, and from their various and often indistinct ineli- 
nations. They sett to be eneotinediate ‘to -Ahe _primiti 
— north east being situated in inaccessible fastnesses, T am 
nt of their nature. On penetrating for two miles in 
Kes direction by means of a marshy creek, I found = 
limestone is universal. “Easterly they are bordered by : a 
very 9 ~ aa 4 ra which, as soy as my limited experi- 
Vo No. 
