262 
throughout the rock. There is a good deal of indefinite chloritic 
matter in the slide, and some has developed in well formed flakes (ripido- 
lite ?). There are some scattered grains of quartz, and, rarer, brookite, 
probably derived from the clay-slate needles.* Secondary limonite occurs 
in places. 
The altered sandstones are reddish or vellowish-grey in colour, and 
show indistinct spots at times. They can be scratched with a knife. 
Plentiful muscovite flakes and small quartz grains can be seen in the hand 
specimens. 
The greater part of these rocks is composed of sand grains, which are 
sometimes enclosed in the larger muscovite flakes that have been developed 
by the contact metamorphism. There are small prisms of tourmaline that 
have evidently been developed in situ. Some are quite minute, and en¬ 
closed in the quartz, but can be recognised by their strong pleochroism. 
The finer parts of the rock are made up of small muscovite flakes, with 
plentiful chloritic material and quartz. There are fairly plentiful grains 
of brookite. 
Table showing the secondary minerals found iu the rocks examined 
from the Bendigo district:— 
—— 
Rocks at 290ft. 
Rocks below 
3,800ft. 
Rocks near 
Ravenswood. 
Grano-diorite. 
Quartz 
*X* 
* 
Sericite 
% 
• • • 
Muscovite 
• • > 
... 
*r 
Tourmaline 
• • < 
e • • 
•u. 
*7P 
Clay-slate needles 
* 
• • • 
Chlorite 
J£. 
•u. 
'A* 
•!<. 
•n* 
Brookite 
• - • 
* (rare) 
* 
Haughtonite 
• • • 
. . . 
* 
Pyroxene 
... 
• . . 
*. 
Cordierite (?) ... 
• . • 
Je. 
*w 
* Indicates occurrence of mineral. 
As a result of this examination, there can scarcely be any doubt that 
the rocks at 4.000 feet, in the Victoria Reef and New Chum Railway mines, 
are not within the zone of alteration produced by the' grano-diorite. The 
only mineral that suggests the slightest change due to thermo-metamorphism 
is the brookite, which occurs sparingly in one of the sandstones, and 
may have been produced by the heat from some neighbouring dvke. The 
rocks at 1,600 feet from the grano-diorite have been shown to be con¬ 
siderably altered, so it may be concluded that the deepest parts of the 
mines are at least 2,000 feet from the grano-diorite, probably a good 
deal more. 
[.Report sent in 3rd August, 1905.] 
* Harker. Researches on Thermal Metamorphism.—Science Progress, 1S90. 
