18 PLUTONIC ROCKS.—CASE III, 
(sce No. 6, Table of Analyses) proves it, however, clearly to be “ albite,” 
and the rock is therefore diorite, according to recent views on petro- 
graphical classification. 
The adjoining fossiliferous strata are not, or but 
very slightly, altered, and hand specimens can easily be obtained, in which 
one half consists of black slate, with well preserved graptolites, and the 
other of the porphyritic variety of the intrusive rock. The brecciated 
variety, apparently a mixture of chips of Silurian rock and of the 
dioritie paste, occurs in places only along the boundary ‘of the two 
formations. 
#71, Micacrous DIORITE. 
Castle Reef, Raspberry Creek, near 
Wood's Point. 
Dense, greenish-grey base, probably 
an intimate mixture of triclinic felspar 
and hornblende. ‘The mica occurs in 
silvery thin plates, and has a talcose 
appearance. It occurs as a dyke, in 
which rich auriferous quartz-veins are 
worked. 
*72) DIORITE (?) 
Same locality as 71. 
Probably No. 71, partially decom- 
posed. 
73. GREENSTONE (Diorite). y 
Near Bushy Creek, Hopkins’ Hill. 
Hard, dark-colored rock, composed of 
triclinic felspar and hornblende, 
74, GREENSTONE (Diabase). 
List No. R 125. 
Summit of Mount Camel, near 
Heathcote. 
Hard, black, fine-grained, crystalline 
rock. 
75. GREENSTONE (Diabase). 
List No. R 125. 
Summit of Mount Camel. 
Dark greenish-black rock, made up 
of crystals of hornblende, with a little 
felspar. i 
76. GREENSTONE (Diabase). 
List No. R 125. 
Mount Camel. : 
Containing crystalline veins of calcite. 
77 and 78. GREENSTONE (Diabase). 
List No. R 124. 
Blake’s Farm, 4 miles south of 
Mount Camel. 
This rock has the appearance of being 
horizontally stratified. It contains veins 
of calcite and alternate layers of greenish 
and reddish colored fibrous crystals of 
some pyroxenic mineral. 
79. SELWYNITE. List No. Rb 21B. 
This mineral is allied to “pyrosclerite,” 
but differs materially from it in its che- 
mical composition and physical proper- 
ties, and therefore forms a new mineral 
species. It occurs massive, as a vein, 
in the Upper Silurian rocks, 4 miles 
north of Heathcote, and is traversed by 
thin seams of tale. Its hardness is 3'5; 
specific gravity, 2°53; color, various 
shades of green to black. It was ori- 
ginally mistaken for a copper-ore. It 
is translucent on the edges, fracture 
uneven and splintery; lustre earthy ; 
takes a fair polish, and might, perhaps, 
beusedforornamental purposes. Before 
the blowpipe it becomes white, and fuses 
on the edges to a greyish-white, blebby 
glass; gives off water in a mattrass ; 
colors the beads Of borax and salt of 
phosphorus faintly chrome-green, and 
is only partially soluble in strong acids. 
A quantitative analysis by Mr.J.Cosmo 
Newbery gave the following results :— 
Silica... ye 47:15 
Sesqui-oxide of chromium 76l 
Alumina Xz; vee 3323 
Magnesia wo 84°56 
Water ... 6:23 
98°78 
80. SELWYNITE (in part). 
List No. Rb 21g. 
From the same locality as last. 
This specimen consists of a green and 
white mottled mixture of selwynite, tale 
and veins of a white mineral, or rather 
two minerals, of different degrees of 
hardness, 
. Those marked with an * occur as dykes (Elvans). 
