﻿158 ALLUVIAL BEDS. July, 



tioned above. The musk-ox does not come to the 

 south of the arctic circle. 



In the evening we pitched our tents on a small 

 island, being one of a group known as Desmarais's 

 Fishery, and from a party of Indians encamped on 

 a neighbouring point we obtained a supply of fish. 



The whole south shore of the lake, westward 

 from Slave River, is low and level, and is lined in 

 parts, and especially between Hay River and Des- 

 marais's Islands, by rafts of drift-timber, which, 

 pressed on shore by northerly winds, become water- 

 logged and covered with sand mixed with commi- 

 nuted wood and decaying grasses. As this buried 

 forest accumulates, willows and balsam poplars 

 spring up from its surface, and bind all together by 

 their roots. The swamps that extend backwards 

 from the lake appear to have originated very much 

 in this way ; and had the locality been one where 

 there was much drift-sand, the erect trees might in 

 parts have been swallowed up and killed by sand- 

 drifts, having their roots in the subjacent lignite or 

 shale. In Slave Lake, however, the sand does not 

 act so conspicuous a part as in Lake Winipeg. 

 The recent deposits conceal the limestone strata, 

 except at a very few places, but the numerous frag- 

 ments which line the beach show that a bitumin- 

 ous limestone, associated with a black shale having 

 a resinous streak, and a thin marly slate, must 



