﻿102 LENGTH OF THE MISSINIPI. June, 



to the brownish glassy sienite mentioned in a pre- 

 ceding page. 



The funnel-shaped arm named Deep River {La 

 Riviere Creuse) meets the northern point of the 

 lake at an acute angle, enclosing between it and 

 Clear Lake a triangular peninsula. Beaver Kiver, 

 the principal feeder of the lake, flows from Green 

 Lake, which lies directly to the southward, near 

 the valley of the Saskatchewan in the 54th 

 parallel of latitude. The winter path from Isle a 

 la Crosse to Carlton House ascends this river to 

 its great bend, whence it leads to the Saskatche- 

 wan plains, through an undulating country but 

 without any marked acclivity. I consider it proba- 

 ble, therefore, that Isle a la Crosse Lake and Carl- 

 ton House do not diff"er more than two hundred 

 feet from each other in their height above the sea. 

 The altitude of the latter I have judged to be 

 about eleven hundred feet ; and Captain Lefroy, 

 from his experiments with the boiling-water ther- 

 mometer, assigns an elevation of thirteen hundred 

 feet to the former. 



Churchill River, disregarding its flexures, has a 

 course to the sea from Isle a la Crosse Fort of five 

 hundred and twenty-five geographical miles, and 

 the length of the Saskatchewan below Carlton 

 House is six hundred and thirty miles. The 

 general descent of the eastern slope of the con- 



