284 GEOLOGY OF TONOPAH MINING DISTRICT, NEVADA. 



The similarity of Redjang Lebong to Tonopah has been commented upon by 

 Mr. Percy Morgan," judging from the writer's earlier description of Tonopah b 

 and from reports concerning Redjang Lebong. This similarity was also called 

 to the writer's attention by Mr. L. Hundeshagen, who has personally visited both 

 districts. The discovery of selenium in the Tonopah ores, in somewhat the same 

 proportion as indicated in the above analysis, subsequent to the comparisons 

 made by these gentlemen, strikingly strengthens the resemblance. 



Five miles west of Redjang Lebong is a similar occurrence of gold ore in 

 altered andesite, at Lebong Soelit. 



In southeastern Borneo gold occurs in altered andesite/ 



The northern arm of Celebes is gold bearing. The mine at Palehleh is in 

 altered andesite, often having a dioritic aspect. The ore contains pyrite, galena, 

 zinc-blende, and copper pyrite, with a little antimony and arsenic, and carries 

 gold and silver, of which the sulphides contain gold about 4 ounces and silver 

 12 ounces to the ton/' Forty miles west of Palehleh, at Soemalata, the ore is in 

 andesite or u porphyrite." f The ore is like that at Palehleh heavy sulphides with 

 some quartz gangue, more often feldspar. Ten miles west of Palehleh, at Denuki 

 Bay, are ores similar to those at Soemalata, but containing more quartz, in altered 

 andesite. Analysis of the sulphides shows zinc, 31 per cent; lead, 8 per cent; 

 copper, 1 per cent; gold, 5.3 pennyweights to the ton; silver, 4.9 ounces to the 

 ton; arsenic, 2 to 4 per cent; antimony, 4 to 6 per cent. On the south coast of 

 the peninsula, at Totok, are heavy auriferous quartz veins in altered andesite; 

 also 6 miles southwest of Totok, at Kataboenan, where the andesite has been 

 intensely silicified on each side of a central fracture, forming a wide mass of ore 

 of the following average composition: Gold, 4 pennyweights per ton; silver, 1 

 ounce per ton; sulphides, 6 per cent; vein quartz, 3 per cent; the remainder 

 being altered andesite. 



Still farther along the Tertiary-Pleistocene volcanic zone lies New Zealand. 

 The late Eocene-early Miocene andesites of the Hauraki Peninsula, in the north 

 island of New Zealand, contain throughout veins bearing gold and silver. The 

 whole peninsula has produced $50,000,000. Near the veins the 'andesite has been 

 altered to calcite, chlorite, serpentine, quartz, and pyrite. The ore in the Thames 

 district is chiefly native gold alloyed with 30 to 40 per cent silver. Associated 

 minerals are dolomite, pyrite, chalcopyrite, zinc- blende, galena, stibnite and ruby 

 silver, arsenopyrite, and native arsenic/ Great masses of quartz are very low 

 grade, but bonanzas of very rich ore occur at the intersection of feeders with the 

 main vein. 



a Eng. and Min. Jour., May 4, 1905, p. 862. rtTruscott, loc. cit., pp. 66-67. 



t> Ibid., May 2, 1903. eTruscott, loc. cit., p. 68; also Suess, E., I>a face do la terre, vol. 8, p. 341. 



oTriuicott, 8. J., los. cit., p. 63. /Lfndgren, W., Eng. and M!n. Jour., Feb. 2, 1905, p. 218. 



