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EDWARD S. SIMPSON, B.E., F,C,S, : 
Cerium Group of Metals — This group includes four rare 
metals, viz. : — 
Cerium Neodymium 
Lanthanum Praseodymium. 
Of these, so far as we know, cerium, the first to be dis- 
covered (1803), is the most abundant, praseodymium the 
least. None of the metals have any practical application and 
the only compounds in use are the oxide of cerium, which 
is used in small quantities in the Welsbach mantle, and the 
oxalate of cerium, which is used medicinally. 
Cerium is suspected to be somewhat widely distributed 
in very small amounts as an original constituent of granites 
and allied rocks. Monazite, phosphate of cerium, etc., 
can usually be detected in the beds of streams draining 
granitic areas. Together with more or less of the other 
three metals of the group, cerium forms a large proportion 
of several minerals found in pegmatite veins, chief of which 
are monazite (phosphate of cerium, etc.), and allanite 
(silicate of iron, cerium, etc.), both of which are known to 
occur in this State. Details of these occurrences follow. 
Moolyella.* * — Monazite. Plentiful in alluvium in 
brown opaque pebbles ranging in weight from 0.05 to over 
4.0 grammes, average about 0.15 gramme. The pebbles are 
often crystallised, but are mostly sub-angular or rounded 
The composition of this mineral is given below. 
Cooglegong.* — Monazite occurs here in considerable 
amount and similar in every respect to the Moolyella mona- 
zite, but in larger fragments, up to 10 grammes, the average 
being about 0.6 gramme. Analysis given below . Fergus- 
onite, euxenite and gadoliniie containing a little cerium, etc.,, 
see pages 9, 22. 
Shaw Tinfield (near Cooglegong). — A little brown 
monazite in stream tin ore. 
Wodgina. — Traces of cerium metals present in Mackin- 
toshite, Thorogummite and Pilbarite. See page 10b. 
Pooxah. — A few small fragments of monazite in 
stream tin ore. 
Fraser Range. — A few masses of allanite have been 
received from this locality. 
Greenbushes. — A few small fragments and crystals 
of monazite in stream tin ore and zircon sands, see page 16. 
Donnelly River. — Small quantities of monazite sand 
in some of the tributaries of this river. 
Most of the black sands of the South-West Division 
yield traces of monazite. 
* E. S. Simpson : ‘Further Occurrences of Tantalum and Niobium 
in Western Australia.” 
* G. S. W. A. Bull 48 :The Occurence of Monazite at 
Cooglegong and Moolyella. 
