16 PLUTONIO ROCKS.—OASE III. 
*53. HORNBLENDE PORPHYRY. 
Upper Yarra. 
The upper face of this specimen ap- 
pears to be a vein, composed of a base of 
felspar, with hornblende crystals and 
a little white mica. The under side is 
the rock in which it occurs: a base of 
felspar, with greenish-black mica. 
54. FELSPAR Porpuyry. 
Black Mountain, Snowy River, 
Gippsland. 
Brown, felspathic base, with quartz 
and felspar crystals, and enclosed frag- 
ments of a black, probably hornblendic 
mineral. 
55. APHANITE (?). 
List No. Rs 31. 
Mount Dryden, Glenorchy. 
Hard, light-green rock, composed of 
soda-felspar and silica, 
56. GREENSTONE. List No. Rs 35. 
Same locality as last, 
Base of No. 55, with felspar crystals, 
partly decomposed. 
57. GREENSTONE. 
Same locality. 
Greenish rock, having a felspathic 
base, with triclinic felspar crystals and 
a green mineral, $ 
List No. Rs 34. 
58. GREENSTONE. 
Same locality. 
Dense, hard, dark-colored rock, com- 
posed of triclinic felspar and probably 
hornblende. 
List No. Rs 30. 
59. PORPHYRITIC DIORITE. 
Map No. R 24. 
East of Lancefield. } sheet 5 8.E. 
Grey base, with crystals of triclinic 
felspar, hornblende and occasionally ar- 
senical pyrites. Very hard and heavy. 
60. DENsE DIORITE. 
East of Lancefield. } sheet 5 S.E. 
Dense, hard, dark-colored, hornblen- 
dic rock. (See “Building Stones,” Nos. 
11, 12, 13, and 14.) 
Note.—The greenstone (diorite) composing the range to the east of 
the parish of Lancefield,is very variable in its lithological character. Mount 
William, at the extreme northern and highest part of the range, and at 
its junction with the Great Dividing Range, is composed of a very hard, 
dark-greenish-black, dense rock (aphanite), closely resembling a basalt, 
and with a metallic ring, when struck, like clinkstone; passing south- 
wards to a lighter green, hard rock, with crystals of triclinic felspar, some- 
times having the appearance of a greenish-white rock, with black dendritic _ 
(hornblendic) markings. . This stone (see “ Building Stone Cubes,” R 30, 
31, and 32), were it not for its extreme hardness, and consequent difficulty 
and expense in quarrying and working up, would make a very hand- 
some stone for building or ornamental purposes. Further south it 
passes‘into a black, highly crystalline, hornblendic rock, and then again to 
a dark-green dense rock, with specks of iron pyrites.. Near the centre of 
this range (see 4 sheet 5 S.E.) is a fault cutting off the greenstone. Its 
place is supplied by a very rich and heavy brown iron-ore, or hematite 
(see Mineral Collection, Case 18, No. 36). The greenstone weathers 
externally to a rusty-brown color. The unfossiliferous Silurian shales, 
resting as small outliers on the top of this greenstone range (probably 
the remains of a denudation of the sandstone upheaved by it), and also 
the contiguous rocks on the west side, are all highly metamotphosed, the 
shales being converted into a hard jaspery porcelanite. About a mile 
N.E. of Mount William is the site (locally called “The Native Toma- 
hawk Quarries”), whence the aboriginal tribes of the neighboring districts 
have procured the greenstone used by them for making tomahawks. 
From the amount of broken stone covering a large area, this quarry must 
have been in use for a very lengthened period. 
Those marked with an * occur as dykes (Elvans). 
o 
