BY W. F. PETTERD, C.M.Z.S. 27 



large quantity, with carbonate and sulphate of lead, above 

 the sulphide zone in the silver-lead mines. It is occasion- 

 ally highly argentiferous. The following mines have 

 afforded fine examples: — Comet, Adelaide Proprietary, 

 Silver Queen, Godkin, and Whyte River. 



46. BiSMUTosPHARiTE ( Bismuth Carbonate). 



The anhydrous bismuth carbonate is of uncommon occur- 

 rence. It occurs in spherical forms aggregated together, 

 with fibrous radiating structure. The colour is pale-yelbw 

 to grey. It is not known crystallised. Occurs sparingly 

 at the Shepherd and Murphy Mine, Bell Mount. 



47. BiOTiTE fOrthosilicate of Potassium, Magnesium^ 



Aluminium, and Iron). 



This is the common black or dark-coloured mica which 

 forms such an important essential in many rocks. It 

 crystallises in the monoclinic system with a pseudo-rhombo- 

 hedral habit, but often with an hexagonal outline, and is 

 abundant as irregular imbedded flakes or scales. It may be 

 transparent or opaque. Biotite is an abundant constituent 

 in crystalline rocks, such as gneiss, and is often associated 

 with muscovite. It is also common in eruptive rocks, such 

 as granit-e, syenite, trachyte, andesite, and others. It also 

 results from alteration in contact rocks, and may be 

 secondary to many mineral species. It is abundant of a 

 greenish colour at Mt. Heemskirk ; of a frondose form at 

 North Pieman ; in somewhat large plates on the east 

 central side of Flinders Island ; and many other localities 

 in its rock-forming character. 



48. Bi SMITE (Oxide of Bismuth). 



Of very rare occurrence. It is found as a thin yellowish 

 earthy coating on other bismuth minerals at Mt. Ramsay ; 

 in arborescent crystal groups, occurring in the cleavage 

 planes of country-rock, colour of a greenish-yellow, 

 Hampshire Silver Mine (W. R. Bell) ; West Cumberland 

 Tin Mine, Mt. Heemskirk: at the Curtin-Davis Mine, 

 Dundas, where it is highly argentiferous. 



49. Bismuth, Native. 



Abundantly distributed throughout a sub-crystalline 

 black hornblende or amphibole of massive structure that 

 occurs as an extensive lenticular formation at Mt. Ramsay. 

 The metal is freely distributed in small irregular particles 



