92 RECORDS OF THE AUSTRALIAN MUSEUM. 



LE^vIs Ponds, Near Orange, New South Wales. 



This occurrence of angles! te is mentioned in the " Census of 

 New South Wales Minerals" drawn up by a Committee of the 

 Australasian Association for the Advancement of Science in 1 890," 

 where the locality is given as the New Lewis Ponds Silver Mine, 

 and it is said to be associated with cerussite and silver ores. On 

 the specimen in the Australian Museum numerous crystals of 

 anglesite are scattered over the surface of a crumbling, limonitous 

 gossan. Many of the crystals are greenish in colour, and 

 are said to contain copper. I was unable to prove the 

 presence or absence of copper definitely on the quantity 

 of material I felt justified in sacrificing, but it may be present 

 in small amount. Anglesite with a green or blue tinge is com- 

 monly observed, and this may perhaps be due to an isomorphous 

 mixtuie of anglesite with a small quantity of the anhrydrous 

 copper sulphate hydrocyanite, wliich crj^stallises in the ortho- 

 rhombic system with axes and angles not far from those of the 

 barite-anglesite group. 



The Lewis Ponds ciystals show two somewhat different habits ; 

 in one the predominant forms are c (001), m (110), and d (102), 

 and the crystals are elongated along the macro-axis (PI. xix., fig. 

 5) ; in the other, by increase in the size of c (111), m is reduced 

 to a narrow plane, and the crystal is almost acutely terminated 

 on the a and ^ axes ( PL xix., fig. 6). The crystals of the second 

 habit are much smaller than the othei's, the two shown in 

 PI. xix., figs. 5 and 6 measuring respectively 5 mm. X 8 nim. X 5 

 mm., and 3 mm. in diameter. Only the lai'ger crystals are 

 greenish, the smaller being colourless with a greasy lustre. The 

 table below gives the mean co-ordinate angles obtained from the 

 two figured crystals. 



Proc. Austr. Ass. Adv. Scl, ii., 1890, p. 207. 



