MINTKAItKltCAI. NdTKS AN' DKWSON. 



•>'t 



onos fo. tl.e la.v ir.r, gav. values for ./. of ir IM «-? 1^^ ^''^ '('^ -''f "' 

 11 1<.') ana for , 45^ 34' au.l 45^ :U' (calonlated 45° ^: ')■ J^'' '^^" '»- 

 r,r,lthe .neanof^ix measurements gave ^, 45 ' 1' p S2 'lU (calenlated 

 45° 0' Hl°57') In another crystal the faces of tl.e octahedron are 

 larger', and two very narrow planes of a possibly "^w tetrahexahedro,. 

 , (307) were observed, the values obtained for p being 23 10 and 2., IS 

 (cVlcnlated 23° 12'). These two forms require conhrmation before they 

 are accepted. 



Angles : 



Mount Bonnie, Northern Territory. 



(PI. viii., figs. 5, 6, 7.) 



The Mount Bonnie Mine is in the Margaret ^]^f\^l Jj;^ 

 Wo-gaman Province, about four miles south of the point wheie tl e 

 Darwin to Pine Creek railway crosses the Margaret River. According to 

 U^ H I. Jenseir^i the lode may be regarded as a gash vein formed by 

 strong movements on two fissure directions, and the surface «^o^« ^^^^^ 

 gossany ironstone outcrop containing small amounts of lead gold, and 

 silver In a fifty feet shaft very good carbonated lead ore was 

 e lountered in a /ed vughy gossan. A tunnel was ^f-^^- ^^^^^^^^^^^ 

 cutting the lode two hundred feet below the outcrop, but apparently the 

 primary sulphide ore has not yet been reached. 



The mimetite occurs in a reddish or yellowish f "^^f^"' *^« J»,^^^ 

 crystals being found in vughs which are sometimes lined with botryoidal 



:n Jensen-Bull. North. Terr., No. 16, 191(i, pp. 3(i. 37. 



