Index No: MRTN103100; Collected By: Thomas B. Nolan; Sample Type: hand sample; thin section; Notes: Location taken from Tonopah Extension Mine shaft; White, somewhat granular to chalky groundmass, in part irregularly interspersed with a red-brown iron oxide. Elsewhere these hematite? Spots seem to have replaced feldspars. Pyrite is sparngly present. The rock shows sericite porphyritic texture of feldspar phenocrysts in a fine-grained, feldspathic groundmass. The phenocrysts are completely sericitizrd and many have irregular, dendritic patches of red iron oxides throughout the area of the old phenocrysts. (It is possible that these were femags, but feldspars seem more likely). There is one inclusion of a rock with coarser feldspars [...]