GO 



workable deposits. These sulphides are in no case present as dis- 

 seminations through the clastic rocks very distant from the diabase or 

 gabbro, which seems clear evidence that they have been brought up by 

 the latter. 



3rd. As segregated veins which may have been filled subsequently 

 to the irruption which brought up the more massive deposits. These 

 veins are not very common, although certain portions of the more 

 massive deposits may have been dissolved out and re-deposited along 

 certain faults and fissures. 



The composition of the ore varies according to the preponderance 

 of either the pyrrhotite or chalcopyrite in the specimen examined. The 

 pyrrhotite may be said roughly to be composed of 40% sulphur and 

 60% iron, with a varying proportion of the iron replaced by nickel, 

 while the chalcopyrite contains 35% sulphur, 35% copper and 30% 

 iron. The mines of the Canadian Copper Co'y, as the name of the 

 company indicates, were first opened for their copper contents, and it 

 was not until considerable work had been done that nickel was dis- 

 covered to be present in the ore. A large shipment of ore had been 

 made to New York, and a chemist there who was making a volumetric 

 determination of the copper contents by the Potassium Cyanide process, 

 was struck by the great variation in his results, which led him to make a 

 more minute examination of the ore, when he found that nickel was pre- 

 sent. The ore has now become of more value on account of its nickel than 

 its copper contents, and Dr. Peters himself greatly doubted if the mines 

 would pay to work for copper alone. The percentage of nickel and 

 copper varies greatly, as might be expected, but assays of nine samples 

 from the different mines of the Canadian Copper Co'y, made in Novem- 

 ber 1888, will show the usual percentage of these metals. These assays 

 were made by Mr. Francis L. Sperry, and show a range in the percentage 

 of nickel from 1.12% to 4.21%, with an average of 2,38%, while the 

 copper varied from 4.03% to 9.9^° Li ^^^h an average of 6.44%. A 

 minute proportion of cobalt also occurs in the pyrrhotite, usually about 

 ■g^j-th as much as the nickel present. Mr. G. C. HofTman assayed four 

 samples from this district which I collected last summer, and these 

 showed the nickel contents to vary from 1.95% to 3.10%, with an 

 ^verage of 2.25%. Three of these samples contained traces of cobalt, 



