78 THE MINERALS OF TASMANIA. 



degree) and argentiferous. They are, apparently, the re- 

 sult of metasomatic replacement. The arsenides and 

 sulph-arsenides are but sparsely represented in variety, but 

 are occasionally abundant individually. Arsenopyrite is 

 very characteristic of the mineral field in the vicinity of the 

 Scamander River, and leucopyrite occvirs in the Colebrook 

 Mine, in company with axinite and pyrrhotite, and also con- 

 taminates the ores of the North-East Dundas district. At 

 Barn Bluff, zones of the older schists occur, impregnated 

 with pyrrhotite and cupriferous pyrite. A noticeable 

 feature in this last-mentioned district is that, on the ex- 

 posure of the freshly-taken-out mineralised rock, it is quickly 

 coated with an efflorescence of white and yellow iron sul- 

 phates. At the McKimmie Mine, near the junction of the 

 serpentine and Silurian slates, some qiiantity of massive 

 pure niccolite was obtained and exported, but it is not now 

 accessible. The compounds of CI, Br, and I are but 

 sparsely represented; the superficial portions of some of the 

 silver-lead lodes occasionally contain appreciable quantities 

 of cerargyrite, embolite, and, still more rarely, iodyrite. A 

 very impure Halite, occurs at the Salt Pans, east of Oat- 

 lands, and atacamite has been observed in comparatively 

 small spangles on the outcrop of the Comet Mine. The 

 most noticeable discovery in this group is a species recently 

 described under the "name of petterdite, and collected in the 

 siiicious outcrop of the Britannia Mine, near Zeehan. It 

 is a chloride of lead, containing AsjO^, and PgO,, with 

 a smaller quantity of SboO;^. It occni's in implante 

 groups of quasi-hexagonal plates of somewhat large size and 

 attractive appearance. 



Of the fluorine compounds, fluorite is abundant at the 

 Mount Bischoff Mine, where, also, prosopite — a hydrous 

 fluorite of aluminium and calcium — also occurs as a second- 

 ary product. At the Republic Tin Mine, Ben Lomond, 

 as well as at the Mount Black Mine, fluorite is obtained 

 from white to a dark purple colour, sometimes in well-cut 

 but small cubes. Its variety, chlorophane, occurs at 

 Bischoff and Hampshire in amorphous and crystalline 

 bunches. 



In the assemblage containing the oxides of the gold, iron, 

 and tin groups, the number is naturally somewhat exten- 

 sive, and, individually, often exists in considerable quantity, 

 such as asbolite (occasionally cobaltiferous) ; hematite — that 

 at the Blythe River being of remarkable purity, and practic- 

 ally inexhaustible abundance — limonite, pyrolusite, &c. 

 Among the more noticeable are the fine crystal develop- 

 ments of cuprite in the vicinity of Mount Lyell. Its lovely 



