BY W. F. PETTERD. 49 
“This mineral occurs in a dyke of intrusive rock, Quartzose, 
Felspathic, and apparently Porphyritic, containing in the joints 
Millerite, which shows various shades of yellow, in_ brittle 
capillary crystals, with other Sulphides” ; reported to occur at the 
Penguin River with Galena and other minerals. 
157. NICCOLITE (Arsenical Nickel). 
This species is of doubtful identification. I am informed that 
it was found in limited quantity with Galena and Pyrites, at the 
Penguin River. As the mines at this locality have been shut 
down for some time it is impossible to obtain an example for 
examination. It is probable that nickelliferous Pyrrhotite has been 
mistaken for this mineral. An assay made by Mr. Cosmo 
Newberry in 1870, of mixed Arsenides and Sulphides, gave a 
return of 5 per cent. Cobalt and 3 per cent. Nickel (Just, 
“Tasmaniana,” 1879). 
158. NATROLITE (Hydrated Silicate of Alumina and Soda, 
variety—Radiolite). 
A Zeolite occurring as thin white films, with radiating structure, 
in clefts of the diabase rock at Launceston. The identification is 
doubtful. 
159. ORTHOCLASE ( Potash Felspar). 
Exceptionally beautiful crystals of Felspar occur in the neighbour- 
of Kilicrankie Bay, Flinders Island (Gould, Proceedings Royal 
Society Tasmania, 1871). Abundant in fine crystals which are 
often three inches in length, of a milky-white to yellow-brown 
colour, which occur embedded and implanted in a siliceous 
magma at the Great Republic mine, Ben Lomond ; plentiful about 
George’s Bay ; Mount Heemskirk, in the porphyry and granite 
of the locality ; massive and highly crystalline, flesh-red in colour, 
on the east bank of the Mersey River above Gad’s Hill; in 
dykes, of a white to pale green colour, on the west side of the 
Mersey, distant about two miles above the crossing, in large yellow 
crystals, forming a broad band in Granite rock. A dyke composed 
of a solid compact subcrystalline Felsite rock, yellowish-brown in 
colour, occurs on Ben Lomond, which penetrates and crosses the 
Granite near the Great Republic mine. This mass is impregnated 
with a considerable quantity of Galena which is irregularly 
dispersed throughout the mass in flaky particles and solid patches. 
The concentrated Sulphide assays fairly well in Silver, and also 
contains a small quantity of gold; a variety occurs at Harman’s 
Rivulet, near the Parson’s Hood as a band in the Granite in 
somewhat angulated crystals of a dull white: it probably belongs 
to the variety Albite; at Port Cygnet a white variety is plentiful, 
which is found in rather thin crystals about one inch in length. 
They are implanted in a grey magma in Porphyry. 
Felspars of less defined character occur at several other localities. 
