282 



THE GEOLOGIST. 



main dip was north and the disturbed one south — the strike of the 

 rocks being nearly east and west. (Sec. 1 and 2). 



Dip South. Dip North. Dip South. 



Fig. 1.— Spring Bok Vontein. 



Dip North. 



Fig. 2.— Concordia. 



The ore is chiefly copper, with a good deal of iron, a little molyb- 

 denum (sulphuret), an occasional film of gold, and in one instance a 

 lump of tungstate of lime. Oxides, silicates, and carbonates occupied 

 the fissures and the upper parts of the pipe-veins, those, viz., where 

 the surface-action was greater. Black, purple, and yellow sulphurets 

 succeeded at first in good quantities ; but lower in the excavation the 

 gneiss became mere felspathic, less fissured, and at length assumed the 

 form of a felspathic granite, in which only specks of pyrites were 

 observable here and there. Meeting these saddles, whose anticlinal 

 line coincided, or nearly did so, with the strike of the rocks, were 

 twists of the strata, figs. 3 and 4, crossing the strike at various angles, 

 one of which, a horizontal section, appeared on the surface near its 

 junction with the metallic saddle of Koperberg, and had the appearance 



