MAGNETIC ORE. 107 



ore, which analysis shows to be magnetite. It possesses some interest 

 from its position in the lower Cambrian rocks, but on account of the lim- 

 ited amount is of no economic value. Material dried at 104 C. yielded 

 Mr. J. E. Whitfield the following result: 



Per cent. 



Silica 5-29 



Titanic acid None 



Sulphuric acid -36 



Alumina -18 



Ferric oxide 64-69 



Ferrous oxide 18-96 



Mangauous oxide 1-16 



Lime -88 



Magnesia 5-X5 



Water.. 2-Bx 



Total 100-25 



Prospect Ridge. North of the Prospect and Eureka tunnels the main ridge 

 loses its simple anticlinal structure and a synclinal fold, much distorted and 

 broken, takes its place. From about the" line of these tunnels to the northern 

 end of Mineral Hill it is difficult to make out the structural features. The 

 Prospect quartzite, which is obscured for some distance by the overlying 

 limestone, reappears again along the west base of the ridge, curves around 

 on the north side of the small body of granite exposed at the north end of 

 Mineral Hill, and may be traced southward on the east side of Prospect 

 Ridge in a continuous body until terminating abruptly near the Eureka 

 tunnel, where it is cut off by a fault; its eastern extension is determined by 

 the sharp line of the Jackson fault. Overlying the quartzite comes the 

 Prospect limestone, forming the summit of Mineral Hill, with lines of 

 bedding, although much obscured, dipping into the ridge on both sides of 

 the hill. By reference to atlas sheet vu, the synclinal structure of Mineral 

 Hill may be readily understood, the quartzite coming in along the base of 

 the hill on both sides, with the limestone crushed and broken occupying the 

 crest of the ridge. 



That the small granite body at the northern end of Mineral Hill, directly 

 opposite Ruby Hill, exerted an influence in determining the structure of 

 Prospect Ridge, seems evident, but in just what manner it is difficult to 



