LAKE SUPERIOR. 191 



suing the canoe route may be considered as a type of the 

 whole. The surface of that tract is hilly, the granite 

 rising in rounded and sometimes in rugged knolls abruptly 

 from lakes or swamps, but only to small heights above 

 the general level. Here and there, but particularly to- 

 wards the summit of the ridge, there are considerable de- 

 posits of sand, gravel, and loam, with many boulders. 

 The term ridge is used with reference to its being a 

 height separating two depressions ; but its summit is a 

 marshy plateau of some extent, across which narrow 

 winding lakes afford a canoe navigation in a variety of 

 directions. * 



This summit of the water-shed, which, level as it is 

 with respect to its water communications, is rendered very 

 uneven by the protrusion of numerous granitic masses to 

 various but moderate heights, lies much nearer to Lake 

 Superior than to Lake Winipeg ; and in descending to- 

 wards the north, the same rocks appear in succession 

 which have been noticed as forming the bank of the 

 St. Lawrence valley, the " birds'-eye limestone " of the 

 Champlain division of the New York system being the 

 newest -deposit on the Winipeg Lake. 



If we trace the water-shed to the south-west, beyond 

 the head of Lake Superior, by the sources of the St. 

 Louis and head waters of the Mississippi, the uneven 

 marshy surface gradually merges in the sandy prairie 

 lands of the Red River, the Saskatchewan, and Missouri, 

 where the naked rocks disappear, or are to be found only 

 in the deep river channels. 



The manner in which an elbow of the " intermediate 

 primitive rocks," which form the nucleus of the water- 

 shed here spoken of, encloses the head of Lake Superior, 



* Vide map of the district in Franklin's Second Overland Journey. 



