ADELAIDE MINE. 407 



Quartzite, which seems to be somewhat irregular in foim and of Hmited 

 extent. The ore occurs both above this body, between it and the White 

 Porphyry, and below it, or at its contact with the Parting Quartzite. A 

 fragment of unreplaced Blue Limestone is also found resting on the Part- 

 ing Quai-tzite and separating it from the overlying White Porphyry. This 

 would seem to indicate the possibility that many, if not all, of the' ore 

 bodies are the replacement of similar fragments of limestone left by the 

 irregular cutting of the porphyr}-. 



The so-called Adelaide Discovery is a tunnel about fifty feet east of the 

 smelter, adjoining Stray Horse gulch Here was an outcrop of three or 

 four feet of hard carbonate ore, dipping 15° to 20° to the southeast and 

 resting on Parting Quartzite. The tunnel, which starts in a little above the 

 outcrop, ran into Blue Limestone, and a winze from its end is said to have 

 struck the qwartzite below. 



The most important developments in the mine have been made in the 

 Ward shaft This was sunk first through 170 feet of White Porphyry, 

 which was nuich decomposed and for a considerable distance stained a 

 brilliant red, apparently by anhydrous oxide of iron. At this depth was 

 a layer of carbonate of lead, below which were 20 feet of decomposed 

 Gray Porphyry and a second layer of ore resting on coarse-grained Part- 

 ing Quartzite 15 feet in thickness. Below the quartzite was 20 feet of 

 White Porphyry, and again five to six feet of quartzite, representing the 

 balance of the Parting Quartzite formation. Below the quartzite the shaft 

 passed through 75 feet of a very hard, jaspery material, consisting mostly 

 of silica, with only about 5 per cent, of oxide of iron, which is a replacement 

 of the White Limestone. When this material was freshly taken out it con- 

 tained in seams and cavities a reddish gelatinous substance that resembled 

 gelatinous silica in the process of deposition, which would indicate that the 

 replacement of limestone and deposition of silicious matter are still going 

 on. Below this the Gray Porphyry, very much decomposed, was penetrated 

 to a depth of 57 feet. Almost all the decomposed ii-on-stained material 

 taken from the shaft would assay one to five ounces of silver to the ton. 

 At a depth of 330 feet from the surface the porpln-ry was impregnated for 

 some eight feet with silicate and carbonate of copper; some red ox'de and 

 a little native copi)er w^ere also found. The ore pockets found occurring 



