34 



Case 52. character. Tlie strata in wliicli they occur constitute bedded 

 deposits of early Palaeozoic age, and comprise volcanic tuffs and 

 radiolarian-bearing clierts, in addition to the ore-body itself. 

 The ore-body itself is a bed of bigbly metamorphosed rock, 

 charged with pyrites, largely arsenical : tliere is no lode at all. 

 9045, in case 109, shows the junction between the chert and the 

 ore-body ; 9074, the original bedding in the chert. 9044 and 

 9221 are characteristic specimens of the ore-body ; their dark 

 green colour being due to shreds of hornblende scattered through 

 the mass, while the presence of calcite is indicated by the glassy 

 lustre. 



At Brown's Creek, Blayney is another remarkable occurrence of 

 gold . Near the surface, the ore consists of copper- and iron-stained 

 chalcedonic or opaline silica. In this gold is sometimes visible 

 (2439). At somewhat deeper levels a wollastonite garnet rock 

 (6482, assaying 5 dwt. of gold to the ton) and massive magnetic 

 pyrites (6504, assaying 3 dwt. gold per ton) occur. The deposit 

 does not appear to be a lode formation. The white mineral is 

 wollaslonite, the brown garnet. 



To the courtesy of Mr. Warneford Lock, late manager of the 

 "Wentworth Proprietary Mine, the Museum is indebted for the 

 carefully-selected specimens exhibited here. Many of these are 

 accompanied by statements of the composition of the ore and the 

 value of the gold. The rock most directly associated with the 

 gold is serpentine. This serpentine has resulted from the altera- 

 tion of an intrusive igneous rock containing much augitc. The 

 minerals of most frequent occurrence in the ore are calcite, iron 

 and arsenical pi/rites, onagnetic pyrites, native antimony, and 

 antimonite. 9236, a pretty specimen, in which free gold has been 

 deposited along the cleavage planes of the calcite. (See also 9235.) 

 Arsenical pyrites frequently shows gold freely; at other times 

 the assay value may be very high without gold being visible. 

 6710, arsenical pyrites cut and polished to show the manner in 

 which the free gold ramifies through the pyrites. 



