THE MINING AND QUARRY INDUSTRY I915 8l 



of the gangue are dolomite and lime-magnesia silicates, with 

 serpentine and talc as alteration products of the latter. 



The Edwards mine has a peculiar place in the zinc-mining in- 

 dustry at the present time, being the only representative of its type 

 in the country. Similar deposits of sphalerite occur in the Pre- 

 cambric limestones of eastern Canada and have contributed small 

 quantities of ore for smelting, but so far as known this is the only 

 active enterprise based on such deposits within the United States. 



The operations of the Northern Ore Co. are in charge of Justice 

 Grugan as manager. 



The belt of crystalline limestones in which the deposits lie 

 stretches to the southwest of Edwards in unbroken continuity into 

 the town of Fowler and is traceable beyond Sylvia lake, which 

 occupies a bowl-shaped depression in the same limestones. Pros- 

 pecting has been active in the district during the last year or two, 

 and many new localities for zinc ores have been discovered. 



Between Edwards and Fullerville there are showings of blende on 

 the farm of Woodcock Brothers, south of the highway, in a ledge 

 of limestone that contains bands of white quartz. Where un- 

 covered the blende is seen in streaks and disseminations that follow 

 the strike of the wall rock and occupy a zone several feet wide. 

 The outcrop is marked by rusty, hornblende material which, how- 

 ever, is of slight depth. The gneiss that limits the limestone belt 

 occurs within 50 feet of the ore. 



The McGill- farm, next on the southwest, has a prospect that 

 shows 2 or 3 feet of light brown blende, free of pyrite. The hang- 

 ing side of the deposit, in contact with the limestone, shows differ- 

 ential movements, with the formation of slip-fiber asbestos. 



On the H. Webb place the ore appears at approximately the same 

 horizon, close to the gneiss, along a ridge of limestone that follows 

 the general strike of the beds. It has been uncovered in several 

 places which seem to mark a more or less well-defined zone of 

 mineralization carrying sulphides in bands and as disseminated 

 grains. Shallow holes have been blasted into the ridge, following 

 the dip of the ore, which is 40 to 6o° northwest. The richer bands 

 are fairly well marked on the borders and attain a thickness of 

 6 to 8 feet. Altogether the ore outcrops and prospects cover a dis- 

 tance of 800 feet along the face of the ridge. The blende is light 

 in color and is admixed with less than the usual amount of pyrite. 

 A. J. Moore of Edwards has explored this part of the district. 



On the McGill farm farther southwest is a prospect with some 

 showings of blende in scattered bunches and disseminations. The 



