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The best example of a marginal deposit is at Creighton, 

 where one of the largest bays of the norite edge has fur- 

 nished the greatest nickel mine worked in the district or 

 in the world up to the present. The Creighton mine began 

 as an open pit, which is now nearly 300 feet deep, with/ 

 lower levels worked by underground mining. The country 

 rock is granitoid gneiss and the ore body which rests upon 

 it dips 34 degrees inwards towards the central line of the 

 nickel basin. The ore is unusually rich, containing about 

 6 per cent, of nickel and copper, the latter making up a 

 quarter of the whole, and specimens showing pentlandite 

 are often found. It may be distinguished from the enclosing 

 pyrrhotite by its octahedral cleavage and brassy color as 

 compared with the bronze of the more common mineral. 

 The greenish yellow of the chalcopyrite is more easily 

 recognised. 



It is interesting to find that the dikes of fresh diabase 

 cutting the rock and ore in various directions are glassy 

 against the ore, which was a good conductor of heat, and 

 only fine grained against norite or gneiss where the chilling 

 was not so rapid. 



The best examples of offset deposits are at Copper Cliff, 

 where a large bay of norite narrows toward the southeast 

 into a dike-like band of norite and ore which ends in the 

 great columnar ore deposit of No. 2 mine. The open pit 

 gives a good opportunity to see the shape of a characteristic 

 offset deposit, which has been followed downwards for more 

 than 6oo feet. 



A quarter of a mile to the south is the once renowned 

 Copper Cliff mine, a still better example of this tvpe, which 

 reached nearly 1,300 feet in depth on an incline of 77 

 degrees to the east, and for years supplied the richest ore 

 in the district, averaging nearly 9 per cent. Most offset 

 mines are richer in copper than the marginal mines and the 

 Copper Cliff ore contained more copper than nickel, justi- 

 fying its name. 



Two other deposits have been worked to the southwest 

 and south at intervals of a quarter of a mile and of three 

 quarters of a mile, but they were of minor importance. All 

 of these ore bodies are associated with some norite spotted 

 with blebs of ore, but they show no surface connections 

 with one another or with the main mass of norite and must 



