2 On the Geography atid Geology 



Thompson, Esq.*, wlio constructed it in 1822, by order of the com- 

 mission to which he is attached, from draughts made with the 

 compass and Massey's patent log, and corrected by frequent ob- 

 servations, for latitude and longitude. I need scarcely add that 

 the maps of Lake Superior hitherto published are incorrect, both 

 as to the outlines of its shores, and its geographical position on 

 the globe. 



Lake Superior (also called Keetcheegahmi and Missisawgaiegon 

 in certain Indian dialects) is contained by the west longitudes 

 84° 18' and 92° 19'; and by the north latitudes 46° 26' and 

 49° r. It is placed to the south of, and near to, the ridge of 

 high lands, which, stretching from the Rocky Mountains to Lake 

 Superior, in broad diluvial plains and undulations, (now and then 

 discovering secondary rocks,) divides the waters flovying into the 

 Mexican Gulf from those of Hudson's Bay ; and which proceeds 

 from near Lake Superior, eastward to the coast of Labrador, in a 

 continuous range of hills, consisting of the older rocks, usually 

 denuded and shattered ; and then constituting the northern dividing 

 ridge of the Valley of the St. Lawrence. 



From near the west-end of the lake this ridge (Iiaving here 

 changed its character) is lost, on the south and east, in the ele- 

 vations of the United States ; but still affords a connected series 

 of successively-descending levels, for the St. Lawrence, its lakes, 

 and magnificent tributaries, the Ottav/a and Saguenay rivers, and 

 Lake Cham plain. 



Lake Superior occupies an irregularly oblong basin, whose 

 length lies east and west, and amounts to 541 miles t, as ascer- 

 tained by Mr. Thompson, with a patent log. This measurement 

 commences from Point Iroquois, at the mouth of the river St. 

 Mary, (communicating with Lake Huron,^ passes on the outskirts 

 of all bays, (except their breadth render the crossing dangerous,) 

 and circumnavigating Point Keevvawoonan, terminates at the mouth 



* Astronomer to tlie Boundary Commission, under the sixth and seventh 

 articles of the Treaty of Ghent, 

 t Always statute miles. 



