JV. 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 of time it 

 has been diluted by rivers, rains, snow, and dews : a con- 

 stant drain materially assisting. The sturgeon, a sea fish, is 

 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 arrangement of evidences. 



Many of the facts just stated, shew that the waters of Lake 

 Huron have been in much greater quantity than at present ; 

 and to them may be added the marshy alluvions, and the exten- 

 sive collections of sand around the bases of precipices, and 

 on the sides of heights. Ancient beaches are not uncom- 

 mon at some distance from the water, as on the Lesser 

 Manitou. It is likewise evinced by the belts of rolled mass- 

 es which gird every slope, and even mark the successive 

 retreats of the lake. 



The dense vegetation v^•hich 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 where the nature and stratification of the rocks 

 are disguised by a multitude of causes. 



The rocks of the districts embraced in the tour of 1820. 

 belong to the transition and secondary classes of Werner. 



The transition formation occupies the north shore of the 

 lake and some of its subordinate islets, from Ion. 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 incli- 

 nations. They appear to be intermediate to the primitive 

 regions on the north and the secondary on the south. 



With respect to the surrounding rocks, those on the north 

 and north east being situated in inaccessible fastnesses, I am 

 ignorant of their nature. On penetrating for two miles in 

 that direction by means of a marshy creek, I found no 

 change. On the north west the transition is succeeded by 

 the first slaty sandstone. On the west and south horizontal 

 limestone is universal. Easterly they are bordered by a 

 very extraordinary rock which, as far as my limited experi- 

 VoL. HI No. 2. 33 



