218 



in the mode of origin of the auriferous deposit at the Linda 

 better materials for forming an opinion : — 



Notes on Specimens of Minerals from Mount Lyell 



(Crotty's Claim). 



No. 7 (Ikon Blow, 56 Feet Wide). 



Composition. Per Cent. 



Iron Pyrites 77'75 



Barium Sulphate (Barytes) 19'85 



Water, etc., lost at a red heat 2 '40 



100-QO 

 Specimen of deep purplish colour, soft and pulverulent, 

 -with indications of lamination becoming apparent as the Iron 

 Peroxide dissolves out in Hydrochloric Acid. The residue 

 insoluble in acid consists of Crystalline Barytes more or less 

 regularly disseminated throughout the mass ; fine specks of 

 gold just visible to the naked eye present in residue. 



Iron Pyrites. — No. 9. 

 (2 chains wide, partly overlying No. 7). 



Composition. Per Cent. 



Iron Bisulphide (Pyrites) 83'0 



Barium Sulphate (Barytes) 17-0 



lOO'O 

 Specimen oxidised on exposed surfaces and in cracks, 

 easily cut with knife owing to the presence of the crystalline 

 Barium Sulphate diffused through it. The particles of this 

 barytes differ but little in appearance from those left on 

 treating with acid portions of the " Iron Blow." 



No. 11 (Cap of No. 10.) 

 Composition. 



Iron Peroxide 



Barium Sulphate 



Silica (Quartz) 



Water, &c, lost at red heat 



Per Gent. 



63-9 



2-2 



18-5 



15-4 



lOO'O 

 Specimen yellow from hydrated Iron Peroxide. 



No. 10 (East of No. 7). 



Quartz or Quartzite ? contained 3'6 per cent, of Barytes, the 

 remainder being chiefly Silica with a little Iron Oxide. This 

 specimen has a distinct schistozie structure and cleavage. 



Nos. 5 and 6— Footwall of lode. 



Two specimens of Hydromica. 



The darker colour of one specimen was due to the presence 

 of organic matter from decomposing vegetation. 



Mr. Ward also states : — " Prom results herewith (which are 



