BY W. F. PETTERD, C.M.Z.S. 23 



cupreous pyritic ore-body of the Mt. Lyell Mine, and is 

 r-emarkable for usually containing an appreciable quan- 

 tity of gold; so much so, that it is at times noticeable as 

 fine granular patches of fair extent. It is reported to be 

 occasionally extremely rich in the desirable metal. 



Mr. R, Sticht informs me that at the North Lyell Mine 

 a pale-green amorphous substance occurs, which might 

 outwardly be mistaken for this mineral. It is apparently 

 a mixture rich in alkalies. 



An analysis gave the following result : — 



Oxygen ratio, 24-85 : 20-44 or 1-21 : 1. 



40. Bauxite (Hydrated Oxides of Aluminium and Iron). 



The important ore of aluminium from which the metal 

 is commercially obtained. It usually occurs earthy and 

 clay-like, and is often discoloured by sesquioxide of iron. 

 The substance apparently originates from the alteration of 

 effusive igneous rocks rich in aluminium and low in silica. 

 A substance from the vicinity of Port Davey agrees fairly 

 well with the general characteristics of bauxite, although 

 no complete analysis has been made. 



41. Bellite (Chromoarsenate of Lead). 



This extremely interesting, and it may be said attract- 

 ive, new substance usually occurs in delicate tufts aggre- 

 gated together, and velvet-like coated surfaces thickly 

 lining and clustering in drusy cavities in somewhat soft 

 iron-manganese gossan. The coated surfaces are often met 

 with of reasonable size, and have been obtained covering 

 several square inches of the gossan, more especially where 

 vughs and fractures occur. More rarely bunches of galena 

 are wholly or partially covered by the substance. It is 

 often in crypto-crystalline incrustations, occasionally pul- 

 verulent, and more rarely in bunches of hexagonal crystals 

 of almost microscopic dimensions. The largest crystals so 

 far observed were but 3 millimetres in length, but the 

 r)utline was sharp and very distinct. The crystals are of 



