﻿1848. ICE IN SLAVE LAKE. 159 



exist in the neighbourhood. They are referri- 

 ble, as has been mentioned above, to the Mar- 

 cellus shale. At the Stony Point, between Hay 

 River and Desmarais's Fishery, fragments of these 

 rocks form the beach, on which some very large 

 boulders of gneiss, sienite, and greenstone also lie. 

 At Desmarais's Fishery I observed the same kind 

 of beach, with the addition of blocks of basalt, 

 of a dull-red sandstone, a coarse conglomerate com- 

 posed of rounded pieces of sandstone cemented by 

 a basis of red clay strongly impregnated with iron. 

 The limestone fragments contained bivalves and 

 corals. On the 6th of July, in the following 

 year, the whole bay that we had traversed in this 

 day's voyage was filled with ice, not yet parted 

 from the shore ; and the lake is scarcely ever navi- 

 gable in this quarter before the beginning of the 

 month*, so that we were only a fortnight later than 

 we could have hoped to cross the lake, had the boats 

 advanced even to Isle a la Crosse the first season, 

 as they might have done under a very favourable 

 combination of circumstances. But this fortnight, 

 by enabling the expedition to be at the mouth of 

 the Mackenzie on the disruption of the ice of the 

 Arctic Sea, would have been of the very greatest 



* Dean and Simpson made tlieir way through it on the 

 24th of June ; the ice, however, was still adhering to the shore 

 at some points. 



