BY W. F. PETTERD, C.M.Z.S. 65 



tricts is often composed of an irregular mixture of brown- 

 spar, siderite, and calcite, with a limited quantity of 

 quartz, most of which is more or less stained with the 

 oxides of chromium and nickel. At Dundas a blue-coloured 

 variety has been obtained associated with galena. The 

 massive form occurs at Mt. Claude, near Mt. Pelion, 

 Heazlewood, and Dundas. 



A somewhat unusual occurrence, in the form of small 

 attached, doubly-curved, or saddle-shaped crystals, which 

 are opaque and white (Magnet Silver Mine, Magnet). 

 Analysis of the pure white form from the Magnet Mine 

 (F. O. Hill): — 



Ca O 31 -72 per cent. = Ca C03 56*64 y)er cent. 



MgO 15-60 „ = Mg C03 32-76 „ 



Fe 3-92 „ = FeCog 8-26 „ 



Mn 1-80 „ = Mn C03 3-76 „ 



101-42 



109. DuFRENiTE f Phosphate of Perojide of Iron). 



Occurs as a thin, irregular encrustation, of an olive to 

 blackish-green colour, on siderite at the Bell's Reward 

 Mine, Heazlewood. 



110. DuFRENOYSiTE ( Sulpkarsenite of Lead). 



This mineral was obtained as thick orthorhombic crys- 

 tals, which are deeply grooved longitudinally, colour lead- 

 grey, highly polished, and occur implanted on and in the 

 cavities of crystalline siderite. Several of the beautifully 

 developed crystals exceeded 1 inch in length and |-inch in 

 width. 



Locality: Block 291, North-East Dundas. 

 Analysis: — 



Per cent. 



Pb = 32-88 



Cu = 9-08 



As = 21-60 



Sb = 8-53 



Fe = 6-42 



S = 21-79 



As: = 0-22 = 73oz. 3dwt.llgr. perton. 



100-52 



