lOa EXPEDITION TO THE 



without having time to search for localities of minerals. 

 In this respect Dr. Bigsb}^ was more fortunate ; he has 

 kindly communicated several to us, and in mentioning 

 them we shall always state to whom we are indebted for 

 them. With this acknowledgment we beg leave to offer 

 to that gentleman our thanks for the liberal access he af- 

 forded us to his valuable collections, as well as for the in- 

 formation which he freely and kindly imparted. 



From Dr. Bigsby we heard that the line had not yet 

 been run ; the commissioners having hitherto been engaged 

 in making separate surveys west of Lake Superior. 



It appears that Rat portage is about nine or ten miles 

 from the northernmost extremity of the lake. The lake is 

 elevated about ten or twelve feet above Winnepeek river, 

 at the point where we left it. Its latitude, according to 

 M'Kenzie is 49° 37' and its longitude 94i° west. Dr. 

 Bigsby set it in latitude 49° 44' 22", probably from an ob- 

 servation of Mr. Thompson's. Previous to our arrival 

 at Rat portage, we observed that the rocks had again 

 changed to a slate, of which the stratification was very 

 distinctly directed from east-north-east to west-south-west. 

 The inclination was nearly a vertical one ; the colour of 

 the slate is a dark green ; it is very decidedly a micaceous 

 slate, at least on Rat portage. This produces the same fea- 

 ture which we had observed in Winnepeek river, above 

 Jack's fall, but which becomes more distinct in the Lake 

 of the Woods. The stream expands and includes an im- 

 mense number of islands. It is to this circumstance that 

 the lake owes its picturesque appearance and its name, as 

 every one of these islands is covered with trees. The as- 

 pect of the lake differs essentially from any other that we 

 had previously seen. At Rat portage our view was limit- 

 ed by an island which nearly closes the bay at which the 



