190 CRUISE OF THE NEPTUXE 



ARCHAEAN. 



Hudson Bay and Hudson Strait. 



The territory comprised in this group includes the islands 

 of Southampton, Coats, Nottingham, Salisbury, Charles and 

 Resolution, along with the shores of the northwest part of 

 Hudson bay, and the south shore of Hudson strait. 



The geological information concerning this group obtained 

 prior to the present voyage is contained in the reports of Dr. 

 Bell, Tyrrell and the writer. 



Crystalline gneisses, schists and granites occupy the eastern 

 and northern parts of Southampton, extending northward from 

 Seahorse point to Frozen strait at the northern end of the 

 island. The rocks near the junction of the Archaean with the 

 Silurian at Seahorse point are largely a very quartzose, light- 

 gray mica-gneiss, associated with bands of rusty-weathering, 

 fine-grained mica-gneiss holding graphite in small flakes, the 

 rusty colour being due to the decomposition of small grains of 

 pyrite disseminated through the rock. This rusty gneiss closely 

 resembles that found in the vicinity of Cape Wolstenholme at 

 the entrance to Hudson strait, and both appear to be similar to 

 the sillimanite gneiss of the Grenville series of southern 

 Canada. Both of the above rocks are cut and twisted by masses 

 of a coarser granite-gneiss pink to red in colour, with pearly 

 feldspar and smoky quartz. All are cut by dikes of f eldspathic 

 pegmatite containing much of the pearly feldspar. 



The only notes relating to the Archaean area to the north of 

 Seahorse point are those of Parry and Back, both of whom 

 mention the occurrence of granites and crystalline rocks in 

 several places to the northward. 



The band of Archaean rocks which crosses the eastern part of 

 Coats island has never been examined closely, and our know- 

 ledge of it is confined to observations made from the ship in 

 passing. 



