BY \V. F. PETTERD, C.M.Z.S. 131 



able as to the quantity thus obtained, as it is the custom to 

 dispose of the mineral to private buyers. 



Mr. L. Keith Ward, B.A., Assistant Government 

 Geologist, in his report, entitled '' The Tinfield of North 

 Dundas " (1909), thus refers to the occurrence of osmirid- 

 ium in the vicinity of the Pieman River :^ — -'"The creeks 

 which carry the largest proportion of the osmiridium are 

 those which traverse a broad belt of serpentine .... 

 at a distance of about a mile from the junction of the Pie- 

 man and Huskisson Rivers .... In mineralogical 

 character the serpentine does not appear to differ essen- 

 tially from the other occurrences of the rock in the dis- 

 trict. It varies in colour from dark-green to a dull green- 

 ish-yellow, and from the weathered surfaces crystals of 

 chromite sometimes stand out in relief. The surface of 

 much of the serpentine is entirely covered by a dense crust 

 of residual limonite, a fact which led to the pegging of 

 the whole outcrop in the boom days by inexperienced pros- 

 pectors, who thought the iron oxide to be the gossan of a 

 large lode-formation. . . The extraordinary feature 



of these ' alluvial deposits ' is the almost complete absence 

 of ' wash.' The creeks have for the most part clean smooth 

 beds, with occasional deposits of sedimentary material an 

 inch or two in depth. The osmiridium is recovered by 

 scraping up the bottoms of the creeks, which consist, as a 

 rule, of soft decomposing serpentine. There are numerous 

 limonite-stained crevices in the bottoms of the creeks, 

 and these act as natural riffles and hold the osmiridium. 

 Especial care is therefore taken to clean out these crevices." 



232. Pargasite (Silicate of Calcium, Magnesium, Iron, 



d:c.) 



Occurs massive, forming a large lenticular rock-mass at 

 Mt. Ramsay. The rock is fine to fairly coarse subcrystal- 

 line in structure, of a black colour with a dull lustre. It in 

 many respects resembles an analagous formation at Big- 

 genden, Queensland ; there is also a strong resemblance as 

 regards the associated minerals, both containing the metal 

 bismuth, pyrites of various kinds, and gold. In the Big- 

 genden Mine the metallic minerals occur of a more oxid- 

 ised or secondary character than at Mt. Ramsay, but both 

 have many striking points of resemblance to each other. 

 The same variety of rock is also abundant at the Hamp- 

 shire Hills, but without many of the minerals common 

 to the Queensland locality and Mt. Ramsay; columnar 

 hornblende occurs at a locality about 6 miles east of the 



