90 



RECORDS OF THE AUSTRALIAN MUSEUM. 



The crystals described in this paper are from the Wianamatta 

 Shale at St. Peters, near Sydney. There are three specimens 

 from this locality in the Museum collection, each carrying a 

 number of crystals, but specimens sufficiently good for guniumetric 

 determination are found on only one. The crystals are either 

 tabular on the basal pinacoid, or prismatic by extension parallel 

 to the brachy-axis. The combinations are comparatively simple : 

 of two crystals measured one showed the forms c (001), m (110), o 

 (Oil), d (102), the other (PI. xix., fig. 2) the forms c (001), b 

 (010), m (110), o (Oil), d (102), z (111). This latter crystal 

 measures approximately 3 mm. X 2| mm. on the basal pinacoid, 

 and, like all the well formed specimens is quite transparent and 

 colourless. The faces of b (010) are very small and were measured 

 in the position of maximum illumination. Only one reliable 

 measurement of the f omi z (111) was obtained. Below are the 

 measured angles. 



ANGLESITE. 



Maestrie's Mine, Dundas, Tasmania. 



Mr. W. F. Petterd says of this occurrence* " many of the 

 crystals obtained at this mine are large and beautifully developed, 

 occurring in masses of considerable size, sometimes containing 

 massicot in the interstices and as a base. Commonly large lumps 

 of galena are coated with anglesite, cerussite and massicot, pre- 

 senting an appearance that has become fairly characteristic of 



" Petterd — Min. Tasmania, 1893, p. 7. 



