xviii. ABSTRACT OF PROCEEDINGS. 
NOTES AND EXHIBITS. 
Prof. Liversrpcx exhibited some mineral specimens. Amongst 
them was a sapphire from Ceylon, which is of a fairly deep red or 
amethyst tint by candle or gas light, but of a blue colour by day- 
light, by the electric light and by magnesium light. The change 
in colour was exhibited to the members. These gems are being 
sold at Colombo as blue alexandrites(chrysoberyl). Many sapphires 
show this dichroism ; but good specimens are not common. He 
also showed the strongly marked fluorescence of some green fluor- 
spar (chlorophane) permeated with plates of native copper, col- 
lected by Mr. Edgar Hall, r.c.s., from the Bald Nob Copper Mine, 
Emmaville, which he is working. Mr. Hall states that the native 
copper occurs at a depth of about eighty feet, where the fluor is 
two feet wide. At lower depths the fluor carries molybdenite and 
above the fipor itis a deep blue colour carrying red oxide and the 
carbonates of copper. Cassiterite also occurs in the lode in a 
gangue of quartz and felspar; but it is there quite free from 
copper and copper minerals. Also some very good crystals of 
mispickel from New England, collected by Mr. D. A. Porter of 
Tamworth, and other specimens. 
Mr. E. F. Prrruay, Government Geologist, exhibited a number 
of specimens of “telluride ores” from Kalgoorlie, and gave @ brief 
description of the geology of those parts of Western Australia 
recently visited by him. The Perth artesian basin was described 
as consisting of deposits of very porous calcareous sandstone of 
wolian origin. The basin is a one-sided one, sloping from the 
flanks of the Darling Ranges on the east to the sea coast on the 
west, the total width of the section being about fifteen miles. The 
rain water collected in these porous rocks evidently leaks into the 
ocean. The Perth basin also differs from most other known 
artesian basins in that the porous rocks are not overlain by — 
impervious beds. It appears therefore that the rising of the 
water above the surface from the bore holes must be due to the 
resistance offered by the sand rock to its passage into the ocean. 
