drawings from thin sections, B
*
Plate XXIII / B. Relations of pyrite and siderite in Tonopah andesite. Drawings from thin sections.
Pyrite (p) surrounding and probably secondary to siderite (s) in earlier andesite, Tonopah and California shaft. Incident light. Magnified 11 diameters.
ex Josiah Edward Spurr (1870-1950 *). Geology of the Tonopah Mining District, Nevada. U. S. Geological Survey, Professional Paper No. 42 / Series A. Economic Geology, 56; B. Descriptive Geology, 66. (1905)
a somewhat more like continents, adrift.
19 May 2013
tags: rounds; J. E. Spurr, Geology of the Tonopah Mining District, Nevada (1905)