ALTITUDE OF LAKE SUPERIOR. 



17 



mouth of the French River to Montreal by the route sur- 

 veyed, is 430-76 miles, of which 35*18 miles is already 

 a good navigation, requiring no improvement. Of the 

 other 78*95 miles, 29*32 will require to be canal naviga- 

 tion, and 49*63 miles improved, so as to connect the whole 

 into a first class navigation for vessels drawing 12 feet of 

 water. 



The cost, exclusive of deepening the Lachine Canal and 

 Lake St. Louis, and apart from land damages and ex- 

 penses, is estimated at 12,026,351 dollars. 



This route would effect a saving of distance between 

 Chicago and Montreal, over the existing one by the 

 Welland Canal, of 343 miles ; but with an increased 

 lockage of 15 locks, and an additional rise and fall of 

 169*60 feet. The lake navigation by the existing route is 

 1145 miles in extent, and the inland or river 134 ; but 

 by the Ottawa, the former is 575 miles, and the latter 

 401 * 



The elevation of Lake Superior above the ocean 

 has been variously estimated by different observers. 

 Captain Bayfield considered it to be 627 feet above the 

 level of the sea, which altitude is adopted by the narrators 

 of Agassiz's tour in that region, and by Messrs. Foster and 

 Whitney, in their report on the geology of the Lake 

 Superior Land District. Sir William Logan, in his Geo- 

 logical Eeport for 1846-7, states that its surface is 597 

 feet above the ocean ; in Professor Hall's Geology of the 

 4th District, N. Y., 596 feet is its assigned elevation. Sir 

 John Eichardson assumed its level to be 641 feet above 

 the ocean. 



The altitude deduced by Mr. Keefer for the map pre- 

 pared for the Canadian Commissioners at the Paris Exhi- 



* Report of the Commissioner of Public Works, 1859 ; based on the report 

 of T. C. Clarke, Esq., C. E. Engineer Ottawa Survey. 



VOL. I. C 



