BY W. F. PETTERD, C.M.Z.S. 121 



quartz porphyry, as a thin powdery crust with molybdenite, 

 at the Blue Tier ; on white opaque quartz at the River 

 Iris, with the sulphide and cassiterite. 



215. MoNAZiTE (Phosphate of Cerium Metals). 



The late Professor Ulrich states (" Minerals of Tas- 

 mania," 1906) :—'' This rare monoclinic mineral occurs in 

 aggregations of small, ill-formed crystals of light-brown 

 colour, generally associated with wolframite, in the lode- 

 stone of the West Bischoff Tin Mine. Its discovery and 

 det-ermination are due to Professor Stelzner, of the Mining 

 School of Freiberg, Saxony, on specimens contained in a col- 

 lection of minerals from the Mt. Bischoff district sent to 

 Freiberg by Mr. Kayser." In the alluvial tin-wash of the 

 Stanley River a heavy sand occurs, which is left in the dish 

 by the ordinary process of prospect)ing. It is very fine, pale- 

 yellow in colour, and semi to quit-e transparent. Under the 

 microscope it is found to be subcrystalline, and much 

 waterwom. This is monazite, and the same remarks apply 

 to the mineral as found at the other localities mentioned. 

 At Salisbury, near Beaconsfield, it is extremely pale in 

 colour, almost white, but otherwise the same. At the south 

 side of Mt. Stronach, near Scottsdale, it occurs in fairly 

 large quantity, and an attempt was made to work the 

 deposit commercially, but it was found, upon analysis, that 

 it only contained about 2 per cent, of thorium oxide, which 

 is the valuable accessory substance that is required. The 

 use to which the thorium oxide is put is for the production 

 of thorium nitrate for the manufacture of incandescent 

 mantles for illumination. At the Fraser River, King 

 Island, an extensive deposit of fine alluvial material occurs, 

 gaid to be rich in monazite (reported to be also poor in 

 Th). It is associated with extrem.ely minute particles of 

 cassiterite and other heavy minerals, all in a remarkably 

 fine state of subdivision. At the Cleveland Tin Mine, situ- 

 ated at the foot of the Meredith Range, the mineral under 

 review is fairly plentiful in the tin-drift ; at the Briseis, 

 Pioneer, and South Esk Tin Mines it is not uncommon, 

 but not of any commercial importance. It occurs at and 

 near the Shepherd and Murphy Mine, Middlesex. In the 

 vicinity of Lottah some comparatively coarse specimens 

 have been obtained, but it does not appear to be plentiful 

 at this locality. At North Heemskirk a fine granular 

 monazite is somewhat plentiful in the alluvial tin drift. 

 It differs from that from most other localities, inasmuch as 

 it is darker in colour, approaching more to brown than the 



