736 
Plate 64, Fig. 2. — PitcJistone. — Sheffield, Tasmania. E. L. Jack’s Collection. With polarizer 
only, magnified 42 diameters. 
Plate 65, Fig. 1. — Basalt. — Eussell Eiver, Queensland. E. L. Jack’s Collection. With. 
crossed nicohs, magnified 60 diameters. 
„ Fig. 2. — Auffite crystal showing twinning. Gympie, Queensland. W. H Bands’ 
' Collection. With crossed nicols, magnified 50 diameters.* 
Plate 66, Fig. 1. — Obsidian. — New Guinea. Sir W. Maogregor’s Collection, With crossed 
nicols, magnified 50 diameters, showing fluxion-structure and 
quartz crystals full of gas pores. 
„ Fig. 2. — Basalt, Burdekin, Queensland. A. W. Clarke’s Collection. With crossed 
nicols, magnified 27‘5 diameters. 
Plate 67, Fig. 1. — Hornblendio dyke running through the Durham Mine, Etheridge, Queens- 
land. E. L. J ack’.s Collection. With polarizer only, magnified 
27’5 diameters. 
„ Fig. 2. — Zeolitic mineral rein running rudely parallel to a calcspar vein in a red 
granite. Eainbow Claim, Charters Towers, Queensland. 
Natural size, drawn from a polished face 
Plate 68. — Daunton’s Hill, Upper Cape Eiver, Queensland. W- H. Bands’ Collection. 
Between crossed nicols, magnified 42 diameters. Mr. Bands 
states that quartz leaders running through this rook cease to 
carry payable gold. (No. 34 in Appendix.) 
Notes to Plate 67, Fig. 2. 
The Analysis of the red zeolite shown in this Plate is as follows : — 
SiOj 470 
H,0 13-7 
This hydrated silicate is common on the Charters Towers Gold Field, occuring in the 
joints of the granite. Various samples have been analysed. The following are selected trom 
many others : — 
1. From the Queen Block Extended, 700 feet vertical .f 
Silica ... ... ... ... ... ... ... ... 4G'23 
Alumina ... ... ... ... ... ... ... 27'33 
Iron ... ... ... ... ... ... ... ... Traces 
Lime ... ... ... ... ... ... ... ... 13'95 
Water (by ignition) ... ... ... ... ... ... 13'47 
101-02 
2. From the Mary Claim, occurring at a depth of 300 feet. 
SiOj 49-04 
Ab^Oj 26-64 
CaO 12-24 
HjO (byignition) ... ... ... ... ... ... 13-30 
Fe,,0, ... ... ... ... ... ... ... .., Traces 
101-22 
3. From the Mexican Claim, at a low depth. 
SiO^ 47-24 
AQO3 26-64 
CaO 12-95 
HjO 14-20 
Fe^Oj ... ... ... ... ... ... ... ... Traces 
101-03 
* Mr. Rands has favoured me with the following description of this rock, which he names Diabase- 
porphyrite : — 
“A dark -green, interbedded, amygdaloidal rook. Amorphous ground-mass, with porphyritic crystals 
sharply defined, and for the most part showing twinning. Magnetite in small grains, and calcite. Amygdules 
filled with carbonate of lime.” 
t Vide Proc. R. Soc. Queensland, 1887. 
