192 CRUISE OF THE NEPTUXE 



The rocks of the south coast of the strait westward from Cape 

 Chidley, as examined by Mr. Caldwell, show that large masses 

 of red and pink mica and mica-hornblende-granite, in a more or 

 less foliated condition, occupy the greater part of the coast area. 

 These granites are newer than the other crystalline rocks asso- 

 ciated with them, which they have inclosed and altered. 

 The older rocks are largely of basic igneous origin, and vary in 

 composition from anorthosites almost free from bisilicates, to 

 hornblendic and chloritic schists containing very little feldspar. 

 A series of light-coloured, high quartzose gneisses is also found, 

 and probably represents altered bedded rocks associated with 

 the basic igneous ones. 



The basic rocks and the light-coloured gneisses are pene- 

 trated by many large dikes of pegmatite from the granites. In 

 many places these dikes are very quartzose, and where they cut 

 the basic masses often contain pyrite and give indications of 

 other minerals. Associated with the lighter gneisses are large 

 long masses of rock, which carry in places considerable quanti- 

 ties of graphite, in others an impure iron ore. The study of 

 these bands has not been sufficient to pronounce as to whether 

 they are veins or beds. 



Ancient crystalline rocks occupy the entire coast-line from 

 the mouth of George river at Ungava bay to Cape Wolstenholme 

 at the eastern entrance to the strait. Mica-granite and, in less 

 quantities, mica-hornblende granite, both more or less foliated, 

 occur along the greater length of this coast. In many places 

 these granites are associated with other gneisses, which are 

 usually lighter in colour, finer in texture, and contain more 

 quartz than the eruptive granite. These lighter gneisses usually 

 are garnet-bearing, the crystals of that mineral being often of 

 large size. In a greater number of places the gneisses of these 

 two series are so closely mingled as to render a separation im- 

 possible ; but there are localities, notably along the west side of 



