58 



term, and at both sides of the deposits the enclosing rock is impreg- 

 nated more or less with the pyritous matter. Though mining is thus 

 rendered somewhat difficult and uncertain on account of the absence 

 of the walls and irregularity in the distribution of the ore, so that there 

 is no means of knowing in what direction to drive the levels, this un- 

 certainty is more than compensated by the extent and massiveness of the 

 deposit when found. The ore bodies like the masses of diabase with which 

 they are so intimately associated are lens or pod-shaped and " pinch 

 out " in both directions. This structure is also characteristic of their 

 downward extension, and the deposits have been very truly likened to 

 a string of sausages, so that when one lenticular body of ore gives out 

 another commences close at hand, which in its turn gives place to 

 another, and though at the Copper Cliff they are down about 600 feet 

 on a slope of 45*^, the quantity and quality of the ore shows no diminu- 

 tion. I have occasionally found true veins of quartz holding this pyrr- 

 hotite, but such evidences of secondary action are extremely rare and 

 proves nothing in regard to the origin of the more massive deposits. 

 The ores and the associated diabase were therefore in all probability 

 simultaneously intJoduced in a molten condition, the particles of pyrit- 

 ous matter aggregating themselves together in obedience to the law of 

 mutual attraction. The ore bodies were, therefore, not contemporane- 

 ous with the stratified Huronian, although there is nothing to prove 

 that they do not belong to the close of the Huronian period. Mr, Fer- 

 rier of the Geological Survey has noticed the occurrence of this 

 nickeliferous pyrrhotite in a specimen of chloritic schist and gneissic 

 granite, which had been taken to show the contact between the two 

 rocks. The pyrrhotite is disseminated through both rocks, and its oc- 

 currence here in the Township of Dill at the junction of what has been 

 called Laurentian would seem to be another proof of the irruptive origin 

 of this gneiss. 



The ore itself is a mixture of pyrrhotite, a monosulphide of iron 

 (Fe7 Sg) and chalcopyrite, a sulphide of copper and iron (Cu Fe Sj). 

 The two minerals are not so intimately commingled as to form a perfect 

 homogeneous mass, but one may be described as occurring in pockets, 

 spots, bunches or threads in the other. The chalcopyrite is not so 

 closely intermixed with the pyrrhotite, but isolates itself rather in spots 



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