386 D. MAWSON AND T, H. LABY. 



Results. 

 A large collection of minerals was examined, and as 

 expected, only those containing uranium or thorium were 

 found to have measurable activity. The apparatus readily 

 detected an activity of iiu that of U a Oo. Among the 

 minerals tested and found to be inactive the following 

 are worthy of mention : — 



Columbite, Barrier Ranges, N.S.W. 

 Stibiotantalite, Greenbushes Tin-field, W.A. 

 Zircons ^ 



Tellurides 

 Bismuth ores 

 Tin stones 

 Barytes 



Various localities. 



As will be noticed in referring to the following table, 

 only two occurrences of uranium minerals have been 

 recorded, so far as we are aware, in Australia. In both 

 cases specimens at hand, up to the present time, are too 

 small to admit of complete investigation. The first is a 

 euxenite occurring with stream tin at the Marble Bar Tin- 

 fields, W.A., and is derived from the degradation of Pre- 

 Oambrian gneiss. The other specimen is a torbemite 1 

 occurring in small flakes adhering to decomposed eruptive 

 rock of intermediate character, and was collected by one 

 of the officers of the Mines Department at the cobalt mine, 

 Carcoar. The association of cobalt and uranium ores at 

 Joachimsthal in the Bohemian Erzgebirge, at Schneeberg 

 in Germany, and occurrence of slightly radio-active silver 

 cobalt ores at Temiscmaringue in Canada has already been 

 remarked by R. W. Brock. 2 This circumstance, however, 

 is regarded by the authors as accidental. 



1 Eecords Mines Dept. N.S.W., Vol. iv., p. 20. 

 3 Loc. cit. 



