ON CUPRIFEROUS TUFFS. 



283 



CHEMICAL COMPOSITION. 



The followng analysis of the tuft' has been made by Mr. J. C. 

 H. Mingaye, F.O.S., Analyst and Assayer to the Department of 

 Mines : — 



Analysis. 

 - - - - ■ 5.32 



" This mineral was dotted over in places with minute specks of 

 metallic copper. Two large assays were made for gold and silver, 

 and neither of these metals f<:iund pi'esent." 



Assays of these cupriferous shales were made for the Department 

 of Mines by Mr. W. A. Dixon, F.C.S., seven were made for gold 

 and silver from the Holt-Sutherland shale, and one for gold and 

 silver from the Heathcote shale, and one from the Holt-Sutherland 

 shale was made for copper, gold and silver. The samples of shale 

 for assay from the Holt-Sutherland bore were selected by Mr. C. 

 S. Wilkinson, F.G.S., &c., and myself. The following is the 

 result : — 



No. 77. Purple and grey shale containing metallic copper. 



Copper 0.21. 



Gold (?) 9 dwts. 19 grs. per ton (?). 



Silver 11 dwts. 2 grs. 



It will be observed that the percentage of copper in this sample 

 was considei'ably higher than in that assayed by Mr. Mingaye. 

 As there was some doubt as to the correctness of the quantity of 

 gold contained in this assay, eight more assays were made for gold 

 and silver, with the following results : — 



No. 81 (a). Dark grey^shale shewing plates of native coppei', 

 and representing a length of six inches of core. 



Silver 8 dwts. 1 1 grs. 



Gold a trace. 



No. 82 (b). Representing a length of twelve inches of dark- 

 reddish grey shale showing flakes of metallic copper. 



Silver none. ^«.*r*"7r 



Gold none. y^^O^^ 



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