192 



The further association of these rare minerals at Radium Hill 

 is of special interest. The only known occurrences of carno- 

 tite are with roscoelite and other vanadium minerals. The 

 existence of mineral vanadates of uranium, such as carno- 

 tite, on theoretical grounds, should not be unexpected, as these 

 elements have a powerful mutual precipitating action. 



In the case of the American deposits, deposition has taken 

 place in fissures, and as a replacement in a Mesozoic sandstone 

 formation, evidently from percolating waters. The ore bodies 

 are wholly of aqueous or secondary origin. The South Aus- 

 tralian occurrence is the result of weathering of certain rare 

 and new minerals in pegmatite veins traversing Pre-Cam- 

 brian strata. This latter occurrence is specially interesting, 

 for the fact that the primary source of the uranium and 

 vanadium can be ascertained. 



A further and most notable fact is that the 

 element vanadium was first discovered by Seffstrom in 

 the titanic iron ore deposit of Taberg, south-west of Lake Wet- 

 ter, in Sweden. The Taberg ore is characterized by the pre- 

 sence of 0*12 per cent, to 0'40 per cent, oi vanadic acid. The 

 ore stock has also in its field relations much in common with 

 the Radium Hill lodes. ''^ 



No trace of gummite, as recorded in the official report, was 

 noted in any of the lode®, and its occurrence is extremely 

 doubtful. 



Pegmatite lodes, of the character of those at Radium 

 Hill, often carry tin and wolfram, though so far these sub- 

 stances have not been reported from the locality, and the 

 absence of even traces of them in the analyses suggests that, 

 likely, the ore body is a pegmatite of a basic rock, and that, in 

 all probability, such minerals will be found entirely absent. 



It may be mentioned that this type of ore deposit does 

 not usually develop pitchblende, but uraniferous titanates, 

 niobates, and tantatates, and thorium minerals may be ex- 

 pected. 



Monazite is found in the same district, in the lode at the 

 King's Bluff gold-mine, 28 miles north-west, which fact should 

 stimulate local interest in quest of thorium m.inerals, and re- 

 inforce the possibilities of the thorium content of the Radium 

 Hill ore. 



This body of radio-active ore is, in the matter of Quan- 

 tity, much the most important yet discovered in Australasia. 

 Its low grade, however, introduces serious difficulties to com- 

 mercial enterprise in this direction. The high value of vana- 

 dium for hardening steel, and the fact that the titanium. 



* Spe "The Nature of Ore Deposits," hv T>v. Py. Beok, trans, 

 by W. H. AVeed, p. 21, vol. i. 



