﻿LAKE WINIPEG. 63 



sandstones, and trap rocks, similar to those which 

 occur on the northern acclivity of the Lake Superior 

 basin ; arid after passing the straits of Lake Wini- 

 peg, we have the granite rocks on the east shore, 

 and Silurian rocks (chiefly bird's-eye limestone) on 

 the west and north, the basin of the lake being 

 mostly excavated in the limestone. The two 

 formations approach nearest to each other at the 

 straits in question, where the limestone, sandstone, 

 epidotic slates, green quartz-rock, greenstone, gneiss, 

 and granite, occur in the close neighbourhood of 

 each other. 



The eastern coast-line of Lake Winipeg is in 

 general swampy, with granite knolls rising through 

 the soil, but not to such a height as to render the 

 scenery hilly. The pine forest skirts the shore at 

 the distance of two or three miles, covering gently- 

 risino; lands, and the breadth of continuous lake- 

 surface seems to be in process of diminution, in 

 the following way. A bank of sand is first drifted 

 up, in the line of a chain of rocks which may 

 happen to lie across the mouth of an inlet or deep 

 bay. Carices, balsam-poplars, and willows, speedily 

 take root therein, and the basin which lies be- 

 hind, cut off from the parent lake, is gradually con- 

 verted into a marsh by the luxuriant growth of 

 aquatic plants. The sweet gale next appears on 

 its borders, and drift-wood, nmch of it rotten and 



