BY W. F. PETTERD, C.M.Z.S. 41 



other mines at Zeehan, and the Heazlewood mines have 

 one and all produced excellent examples, amorphous, sub- 

 crystalline, ajid of perfect crystallisation. It is always 

 an attractive mineral, and one such as soon arrests the 

 attention of visitors to the silver-lead localities, and thus 

 the most elementary collections are almost certain to con- 

 tain specimens. It frequently assays, in common with the 

 sulphate, high in silver, as is the case to a notable extent 

 at the Heazlewood and Magnet Mines. At the Heazle- 

 wood and Whyte River Silver-lead Mines, and to a lesser 

 degree at the Magnet Mine, small almost amorphous 

 masses of a peculiar gray lead carbonate have been found 

 to be remarkably rich in silver, so much so that assays 

 have been made giving returns equal to considerably over 

 1000 oz. of that metal per ton of lead. This result tends 

 to show that the hypothetical silver carbonate (selbite) 

 may have actual existence, and was answerable for the 

 gray, colouration, but tests generally, though not invari- 

 ably, result in proving an admixture of a haloid of the 

 metal. The selbite has never been isolated, so that its 

 occurrence in nature remains unsolved. 



Dr. C. Anderson has studied the Tasmanian crystals of 

 csrussite and states (Records of the Australian Museum, 

 Vol. VI., Part 5, 1907), referring to a specimen from Zee- 

 han, '' One specimen in the museum collection shows 

 several small but well- developed crystals, simple and 

 twinned, on a matrix of galena with patches of friable 

 limonite. A doublet on m was measured and yielded the 

 forms c (001) h (010) m (110) v. (130), .!• (012), k (Oil) 

 I (021) V (031)— z— (041) p (111). The faces in the zone 

 (010, 001) are striated and slightly interoscillating. A group 

 is made up of four individuals, of which I. and IL, also 

 III. and IV., are twinned to each other on m, while I. 

 is twinned to III. and II. to IV. on a possible face (760) 

 for which the colouration value of (^ is 62° 24'. This 

 form has not been recorded for cerussit'e, and it is just 

 possible that we have here merely a case of accidental 

 grouping ; but the measured angles given agree rather 

 well with the assumption that a new twinning law is in 

 operation." 



Respecting cerussite from the Washington Extended 

 Mine, Whyte River, Dr. Anderson writes: — "This is 

 represented in our collection by one specimen, in which 

 small crystals of cerussite occur in cavities in galena coated 

 with yellow limonite; in habit it is tabular on h, which is 

 slightly striated to prism and brachy-dome intersections." 



