186 ON THE GEOLOGY AND PETROGRAPHY OF BATHURST, N.S.W., 



15. Sphene. — The sands, resulting from the decomposition of 

 the granites, are full of magnetic ironstone and titaniferous iron. 

 This material is so plentiful that after floods it will be found 

 deposited as black sand in the creeks to the south of Bathurst and 

 about Kelso. Mr. A. W. Howitt first drew my attention to it in 

 the micro rock-slices. I have since detected wedge-shaped crystals, 

 of a deep brown colour showing dark borders with transmitted 

 light, in slices of granite from near Mt. Stewart. The titaniferous 

 ironsand may be collected in large quantities by passing a magnet 

 through the dry sand in any of the creeks within the granite area. 

 In this sand I have frequently detected titanium by fusing the 

 mineral with bisulphate of potash until decomposed. The fused 

 mass is then warmed in water in just sufficient quantity to dissolve 

 the soluble material. A few drops of nitric acid are added to the 

 filtrate, and the latter diluted with six or seven times its bulk of 

 water and boiled. Titanic acid separates as a white powder. The 

 powder can be further tested before the blow-pipe in a bead of 

 microcosmic salt. 



16. Galena. — Is known to occur in veins and lodes in connection 

 with quartz reefs. So far as observed, it is unknown in granite 

 rocks, but is found at, or near, the junction of the slate and granite, 

 both to the north and south of the granite formation. A typical 

 occurrence of this mineral may be studied near the residence of Mr. 

 Suttor at Mt. Grosvenor, Peel. As has been found in other parts 

 cf the world, the galena here contains variable amounts of silver. 

 It is not found in such large quantities as to make it profitable 

 as a lead ore. The silver assays are always low, the highest not 

 exceeding 20 oz. per ton of ore. 



17. Phosphate of Lead. — Occurs sparingly as an incrustation on 

 decomposed galena ore on the Grosvenor Estate, near Peel. 1 

 have never detected the arsenical variety of this mineral referred 

 to by Mr. Stutchbury, ante p. 176. 



19. Limonite. — Limonite is found as veins filling cracks or 

 joints in the granite. It is clearly in these instances a secondary 



