145 
ected in the centre of an altered mass. The rock was thus, in all likelihood, 
g nally a typical dolerite. It is not surprising that igneous rocks so ancient should 
Undergone much alteration. 
,, Strathmore Creek, on Pelican Creek from Mount Bellavista downwards, and 
O'dal^ River at the north end of the coalfield, the rock is exceedingly amygdal- 
tho ’ cavities, sometimes of considerable size, filled up with prehnite, 
msonite, analcime, or laumonite. With the prehnite, carbonate of copper is frequently 
Q, some specimens of the ore being quite good enough to work if sufficient 
u ities could be obtained. The ore, however, so far as I was able to see or learn, 
occurs in lodes. 
“'C' Samuel Allport, P.G-.8., thus reports* 
%iclote roek”froi 
Mr. Hughes’s) : 
a Must have been originally as scoriaceous as any recent lavas, but now forms 
in r Mass of zeolitic mineral matter. All the cavities are filled with prehnite 
exa • groups of crystals, which exhibit a magnificent display of colours when 
Cent polarised light. One cavity is lined with the radiating prehnite, and the 
oj,j . * portion partly filled with calcite and partly with carbonate of copper. Of the 
oonstituents nothing is left except the magnetite. The forms of felspar 
renl sharp and distinct; but the original substance has been removed and 
brovva^'^ prehnite, differing in no respect from that filling the cavities. The reddish- 
grains and patches scattered through the base probably represent the augite.” 
the B ^ Mount Toussaint and Mount Macedon Eanges, as well as in the bed of 
Unfvo River and Pelican Creek, geodes of opal, agate, and chalcedony are not 
fiuently met with. 
on the microscopic aspect of 
from the “ Bowen Eiver, near McDougal’s head station ” (Birallee, 
J. 
£ 
Quart. Journ. Geol. Soc., xxxviii., p. 315. 
