GREAT RIVERS OF THE UNITED STATES 



355 



pass to the sea. More tonnage passes through the " Soo " 

 canal between Lake Superior and Lake Huron than passes 

 through the Suez canal. Here pass the greatest fleets 

 bearing wheat, iron, and lumber that the world has ever 

 seen. 



The old river which once drained this region passed 

 through various vicissitudes before the present noble 



THE " Soo " CANAL AT SAULT STE. MARIE. 

 Notice the " whale-backs," a type of boat peculiar to the Great Lakes. 



waterway was formed. From Montreal to the sea it has 

 been drowned by a depression of the land. Its upper 

 basin has been enlarged in places by the action of the 

 glacial ice, and in other places it has been dammed, thus 

 causing lakes and falls. 



The Mississippi and its tributaries offer navigable water- 

 ways of about 9000 miles. It is the greatest navigable 

 river system in the world. From the Rocky Mountains 



