COMPARISON WITH SIMILAR ORE DEPOSITS ELSEWHERE. 285 



At Karangahake the ore is argentite, with a little pyrite and free gold, in 

 drusy, fine-grained quartz; stibnite and calcite, with some siderite and a little 

 nickel and cobalt, also occur. At the Waihi mine, which up to the end of 1903 

 had produced $15,000,000, the ores are in altered andesitic rock, and have been 

 covered by later rhyolitic flows. The oxidized quartz contains argentite and free 

 gold, with black oxide of manganese, and oxides of nickel and cobalt; the sulphide 

 ores contain pyrite and blende, with a little nickel, cobalt, and selenium. The 

 country rock is altered, the secondary products including pyrite, carbonate (calcite?), 

 and serpentine. In the veins and veinlets the gangue minerals are quartz, calcite, 

 and adularia. 



There are two distinct flows of rhyolite overlying the andesite, of which the 

 older has a remarkable flow structure, giving it a brecciated appearance." There 

 has been a later period of mineralization, producing gold-bearing lodes in rhyolite.* 



Mr. Lindgren calls attention to the striking similarity between the Waihi mine 

 and the De Lamar mine, in Idaho, described by him a mine already likened to 

 Tonopah by the writer (see p. 271). Mr. Morgan, judging from a personal knowl- 

 edge of Waihi and the writer's description of Tonopah, c calls attention to the close 

 resemblance of these two districts. 



Tellurium occurs in some of the New Zealand districts, varying from traces 

 up to 12 ounces per ton, in picked samples. Samples from various districts show 

 the following types of ores in regard to gold, silver, and tellurium: Coromandel, 

 25 per cent mispickel, gold 200 ounces, silver 90 ounces, a little tellurium; Tapu, 

 2i ounces gold, 250 ounces silver, 7 ounces tellurium; Waiomo, gold 15 ounces, 

 silver 600 ounces, tellurium 12 ounces; Waiomo, Monawai, gold 2 ounces, silver 

 40 ounces, tellurium 4 ounces. No tellurium was detected in samples from 

 Waihi, Jubilee, Komata, Karangahake, and Great Barrier, in which the gold 

 and silver bore the following proportions: Gold 24 ounces, silver 760 ounces; 

 gold 8 ounces, silver 150 ounces; gold 600 ounces, silver 160 ounces; gold 2 

 ounces, silver 256 ounces; and gold 2 ounces, silver 200 ounces. Thus tellurium 

 has been found in a line stretching from Coromandel to Maratoto, but nowhere 

 to the east. rf 



Besides the selenium noted above in the Waihi mine, Mr. Allen found selenium 

 in the ore at Great Barrier. In this New Zealand region selenium and tellurium 

 have not been proved to be present in the same district. This is especially 

 interesting in comparing New Zealand with the Nevada region, where selenium 



"Compare the description of the Tonopah rhyolite dacite, p. 41. 



ftLindgren, ut supra; also Morgan. Percy, Eng. and Min. Jour., May 4, 1905; Trans. Austral. Inst. Min. Eng., pp. 1&1-187. 



cEng. and Min. Jour., May 2, 1903. 



d Allen, F. B., Trans. Austral. Inst. Min. Eng., vol. 7, p. M. 



