190 PHYSICAL GEOGRAPHY. 



feet above the water surface, and the distance of its crest 

 from the margin of the lake at from 20 to 50 miles. 



Many mining stations have been granted to adventurers 

 by the Canadian legislature, but workings are carried on 

 in three only ; viz. one in Pigeon Bay, one among the 

 islands of Nipigon Bay, and the third in Mica Bay. At 

 the last named 100 miners were employed in 1849, when 

 the establishment was broken up by a foray of Chippe- 

 ways, who thought that their territorial rights were in- 

 vaded.* But little ore has as yet been shipped from the 

 Canadian side of the lake. The export of native copper 

 from the United States shore is considerable. In 1849 

 1,114 tons of pure copper were transshipped at Saut Ste. 

 Mary, f 



Our limits will not allow us to dwell longer on the 

 St. Lawrence basing; but with respect to the general 

 character of the ridge which divides it from the Winipeg 

 excavation, the aspect of the country traversed in pur- 



* Narrative, Vol. I. p. 73. 



f The Detroit Free Press states that, in 1850, the shipments ex- 

 ceeded 4,000 tons, and it is calculated that they will equal the whole 

 consumption of the United States, which is 6,000 tons in 1851. There 

 are twenty-two copper companies in operation on the Michigan 

 shores, employing 800 men. The masses of native copper on Kewa- 

 woonan Point are enormous ; but, from their very purity, they can 

 neither be blasted nor hewn out in the ordinary way. The method 

 adopted at present is to use long iron chisels, which are turned slightly 

 by the hand at each blow of the hammer. In this way large slabs 

 weighing two tons or more are cut out, to which not above five per 

 cent, of quartz rock and other impurities adhere. On this point 

 there are said to be parallel ridges of trap rising through beds of 

 sandstone. Among these the native copper lies in walls or veins 

 which have two directions, one running across the trap ridges in 

 N.W. 6 N. i N. direction, the other parallel to the ridges and strike 

 of the sandstone. 



I Professor Agassiz has devoted a large volume to the natural 

 history of Lake Superior alone, which is full of interesting facts and 

 comprehensive general views. 



