191 



(5) : from the extracted matter, the bright black mineral (3) 

 appears to have had its origin. 



Another reef 10 yards to the east is characterized by con- 

 sisting chiefly of the heavy black minerals and abundant mica. 

 It has been opened to a depth of 18 feet. 



Still further east is another reef, chiefly composed of the 

 heavy black minerals and quartz. 



The portions of the lodes exposed by development show 

 ample stains of the lemon -yellow powdery substance deter- 

 mined by the Government Analyst to be rarnotife. It is 

 found coating the black minerals and insinuated into micro- 

 scopic cracks. Undoubtedly this substance is of secondary 

 origin, the field occurrence indicating a derivation by decom- 

 position of some primary constituent of the ore body ; no 

 doubt the black minerals referred to above. 



In one part of the main lode a secondary micaceous mine- 

 ral of a bright green colour is rather abundant, and, as it 

 re-acts strongly for vanadium, is no doubt roscoelife. 



Just as recorded in the cases of the Colorado and Utah 

 occurrences, a large variety of yellowish and greenish mine- 

 rals in various shades, both amorphous and crystalline, are 

 also met with in this material. Their very sparse develop- 

 ment has, so far, not allowed of sufficient quantities being 

 collected for analytical purposes. 



The bris^ht black mineral (3) is an entirely new type, 

 though details are not vet available for complete description. 

 We propose to name it davidite, after Professor T. W. E. 

 David, of Sydney University, whose personal ability, wise 

 counsel, and enthusiasm have done so much to further the 

 interests of the science and economic application of geology 

 in Australasia. 



Conclusions. 



Carnotite is known from one other locality only, namely, 

 as scattered occurrences in a Mesozoic sandstone for- 

 mation, distributed through an arid district com- 

 prising western Colorado and south-ea-stern Utah, 

 in the United States of America. Roscoelite has 

 been reported from three other localities only — Placerville, in 

 Colorado, and neighbouring locality, and Placei'\'ille. in Cali- 

 fornia, both in the United States of America,* and at 

 the Boulder Mine, eastern Coolgardie, Western Australia. f 



* "On Carnotite and Associated Vanadiferoii>; ]Minerals in 

 Western Colorado," bv W. F. Hillebrand and F. L. Ransome. p. 

 9. Bidl. No. 262, U.S.G.S. 



"Vanadium and Uranium in South-Eastern Ftali," bv J. M. 

 Boutwell. p. 200, Bull. Xo. 260, F.S.G.S. 



+ Se<^ W.A. Geol. Survey Reports. 



