52 B GEOLOGICAL SURVEY OP CANADA. 



Limestone are found dipping north-westward at an angle of 50°. This appears, 

 however, to be an abnormal attitude due to local disturbance, for what 

 is apparently the same zone of limestone runs south-westward to the 

 inner end of Harriet Island, and bending sharply round this, again 

 appears on the point at the west side of the harbour, and is here well 

 shown, dipping south-westward at an angle of 45°. The limestone is 

 .grey and cryptocrystalline, and holds cherty concretions together with 

 siliceous veins which stand out on weathered surfaces. The thickness 



Calcareous ash °^ ^ ne ^ e( l i s considerable, but is not completely shown. It is underlain 



rock ' by a peculiar material, which appears to be a felspathic ash rock 



containing a large proportion of calcareous matter. It is grey in colour, 

 speckled by the mixture of light and dark fragments, and shot through 

 with iron pyrites in small concretions and veins. The Bolkus Islands, 

 lying opposite the mouth of Harriet Harbour, in the centre of the 

 inlet, are for the most part composed of similar limestone to that just 

 described. In the bay on the east side of the largest or western island, 

 this is found to overlie a grey rock which evidently represents that 

 described as occupying a similar position in relation to the limestone 

 at Harriet Harbour. It here, however, simulates an amygdaloid in 

 appearance, but is probably similar in origin to the last. The calcareous 

 matter with iron pyrites has formed rounded concretionary masses. 

 This in turn rests upon a massive green amygdaloid of basic character. 

 The thickness of the overlying limestone as shown on this island is at 

 least 1500 feet. It includes some layers of flaggy limestone, and of a 

 dark grey rock of fine grain which may be called an impure limestone, 



rangeuient of an( ^ nas probably been a highly calcareous mud. There can be little 



rocks. doubt but that the limestones of the Bolkus Islands represent those of 



Harriet Harbour and vicinity, being the north side of an anticlinal 

 fold, the axis of which runs westward up the main channel. It is 

 further probable that the same band, leaving the east end of the Bolkus 

 Islands, runs across to the west end of the Copper Islands, and that 

 the bend thus made corresponds with that shown on the southern side 

 of the supposed anticlinal, in Harriet Harbour. The limestone now 

 described is also probably the same with that found in Houston 

 Stewart Inlet. 



Copper islands. The Copper Islands are largely composed of grey sub-cystalline 

 limestones, closely associated, and in some cases interbedded, with 

 greenish dioritic rocks, which are often compact, but occasionally 

 evident altered amygdaloids. The general strike is nearly east and 

 west, with prevailing northerly dips at angles of about 30°. In the 



Copper ore. dioritic rocks, copper ore, in the form of small irregular strings and 

 concretionary masses of copper pj^rites, occurs in many places. These 

 weather conspicuously green, and prove the cupriferous character of 



