350 N. Ji. JiDiner: 



tures tile following sequeuc-e : — Tlie quartz porphyry was intruded 

 t'roni some magma, probably at considerable distance below the 

 then surface, along a plane of weakness, namely, the zone of breccia- 

 tion. After sulidiheatinn, and probably while the dyke was still 

 hot, alkaline sulphide solutions Avere introduced along fissures in 

 the dyke, and these caused the extensive propylitisation. Finally, 

 the gold stibnite and (piarlz were introduced througli the same or en- 

 larged fissures. Contrasted with the above alteration, is the effect of 

 the present day vadose circulation. Pyrites is dissolved from the dyke, 

 and from the brecciated fault zones, and becomes oxidised, and is 

 redei^osited in the lower levels of the mine as hydrated iron oxide. 

 In abandoned and little-used Workings, as in the 'Uiiion mine, long 

 needles and hair-like crystals of epsomite are abundant. Green 

 vitriol (Fe SO^. 7 H^-O), also frequently occurs, due to the oxidation 

 of the pyrites. Where Avater has percolated down the hanging wall 

 of the dyke, considerable altei'ation of the dyke to a clayey material, 

 largely kaolin, has occiured. 



10. ^Additional Features. 



Locahsaf/on of values, evidence of secondnri/ eiiriclinicnf , etc. 



Owing to the rather limited stud}' of the occurrence of the gold, 

 the writer being largely concerned with the then working levels, 

 namely, the two bottoiu ones and the uppermost one, sufficient 

 data were not gained for the fixing of pay shoots of gold, although 

 there is little doubt that they do exist. According to evidence that 

 the Avriter has gained from the officials at the mine, there appear 

 to be two main shoots. 



1. North hanging wall or wliiiu shoot. 



2. South footwall shoot. 



Of these two shoots, the northern one is the richer, and is more 

 well defined lliaii the soutlierii one. They both pitch to the north, 

 tlie nortli one at a very steep angle, and the south one at about 45 

 deg., so that they incline towards one another, and in the 700 feet 

 level the two shoots are only 70 feet apart. The lengtli of the 

 shoots appears to be fairly uniform, and about ^TiO feet. With 

 respect to the cause of the shoots, the evidence is largely of a nega- 

 tive character. Mi-. Dunn,i in his examination of the Union mine, 

 was inclined to think that the shoots were due to the selective 

 infiuence of certain bands of the country roclv. Appearances at 

 the mine point against this, however. The best values occur when 



1 hiiiiii. <))). ('it. 



