102 
EDWARD S. SIMPSON, B.E., F,C.S. : 
Mount Francisco. — Manganocolumbite is moderately 
plentiful here in an albite pegmatite and in alluvium. 
Poonah. — Several fragments of detrital manganoco- 
lumbite weighing from 6 to 13 grammes have been picked 
out from steam tin ore. The specific gravity averaged 5.7 
and the content in Ta 2 0 5 varied from 17 to 25%. in 
Nb 2 0 5 from 65 to 57%. 
Lake Monger District. — A few fragments (weighing 
from 12 to 43 grammes) of iron columbite have been received 
from here. Average assay 'fa, O. , 20% ; Nb 2 0 5 , 62%. 
Londonderry. — Two large fragments of supposed tin 
ore found by Frazer 3 miles west of the famous Londonderry 
gold mine, in 1909 proved to be manganotantalite carrying 
49% Ta 2 0 5 and 34% Nb 2 0 5 . Both of these fragments 
were well crystallised. Later many more small detrital frag 
ments were obtained ranging in weight from 0.5 to 50 
grammes. They were mostly manganotantalite or mangano- 
columbite in about equal proportions. Several crystalline 
fragments contained much tin oxide as well as tantalic oxide. 
These are probably ixiolite. 
Victoria Rocks. — Mr. Frazer, the veteran prospector, 
reports that tantalite occurs at this locality and at intervals 
between here and his Londonderry find. 
Bellinger. — In a mica vein at this locality a little 
tantalum ore occurs ranging from ferro- tantalite to mangano- 
columbite in composition. 
Greenbushes.— High grade tantalite is moderately 
abundant in a greisen vein and in alluvium at the south end 
of this tinfield. Several tons have been raised for the 
market. The mineral rarely shows any trace of crystallisa- 
tion. On splitting some lumps of this ore one finds thin 
fracture fillings and surface replacements of the tantalite 
by a yellow resinous crystalline mineral. This is stibio- 
tantalite (tantalate and niobate of antimony), an extremely 
rare mineral first discovered in Greenbushes by our Hon' 
Treasurer (Mr. J. J. East), and only recently found at one 
other locality in the world. Stibiotantalite is also found in 
small quantities in the stream tin ore, as also is tantalite. 
Tantalum also occurs at Greenbushes in small amounts 
in solid solution in the clean cassiterite. A crystal from the 
South Cornwall lode had the following composition : — 
SnCL 97 ' 6 3 % 
Ta 2 () 5 1.76 
Fe 2 O, , etc .61 
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