66 MINERALS OF TASMANIA. 
Cascade in abundance, commonly in radiating bunches, which are 
occasionally intermixed with Pyrites and Cassiterite; Mount 
Ramsay, in the stanniferous granite abutting on to Amphibole 
rock. 
Green Tourmaline—This is a peculiar and local form 
characteristic of Mount Bischoff, where it practically often con- 
stitutes a rock mass which has erroneously been termed Chlorite. 
The prisms are, as a rule, thin, rather dull in lustre, and of various _ 
shades of pale-green in colour. The crystals rarely exceed one 
inch in length, being commonly quite minute; they some- 
times form small tufted masses, composed of fine acicular prisms, 
in cavities of the rock, but more often they are aggregated and 
intimately interwoven together, forming bunches of consider- 
able proportions. The more commonly distributed black schorl 
has not been found at Mount Bischoff. 
Brown Tourmaline —Obtained in small radiating prisms in 
a quartz matrix at Mount Ramsay; at Glenora; near the gap at 
Mount Heemskirk, in some abundance, of a rather dull hair-brown 
colour. 
Regarding the formation of Tourmaline in nature, the following 
remarks by Mr. A. W. Clarke, F.G.S., will be of considerable 
scientific interest, more especially as this learned gentleman’s 
observations are based upon a studied microscopical examination 
(Jack and Etheridge, jun., “The Geology and Pleontology of 
Queensland and New Guinea,” 1892) :—“ The interesting question 
arises, which of the two minerals ””—referring to this mineral and 
quartz—“is the first born. Rosenbusch says (‘ Microscopical 
Physiography,’ p. 184) that ‘Tourmaline is not directly secreted 
out of the eruptive magma in eruptive rocks, but resulted from 
the action of fumaroles carrying Fluorine and Boron on the 
eruptive rock, especially in its Felspar and Mica.’ Teall also 
alludes to the action of fumaroles in the genesis of Tourmaline. 
This would rather support the pre-existence of Quartz; on the 
other hand, the uniform orientation of the Quartz between and 
alongside of the broken prisms would lead orie to think that the 
reverse was the case. Could it be that the Tourmaline crystallized 
out in the Quartz by the action of fumaroles, as above, while the 
Quartz was viscous and under pressure, and that earth-stresses and 
dynamic metamorphism followed, separating the prisms, after 
which the Quartz proceeded to crystallize? ”’ 
227. TREMOLITE (a pale-coloured variety of Hornblende). 
A variety of a pale green to white colour, generally radiating 
in structure ; is common at Wombat Hill, about three miles from 
Mount Bischoff; radiating in bunches, and also massive, white, and 
shining; in profusion at a locality about three miles west-north- 
west of Mount Horror; at Heazlewood in vughs in the country 
rock; at the Vale of Belvoir it occurs pseudomorphed to Quartz, 
