Index No: NBM055760; Collected By: ; Sample Type: hand sample; Notes: Rock chip sample of partially welded, originally glassy ash flow tuff exposed in unmarked pit approximately 1m deep X 2 m wide in map unit Tau (of Byers et al., 1976). Porous tuff has been acid-leached, replaced by drusy quartz and vuggy silica. Drusy quartz along fractures and forming irregular veins, with silica filling of porosity near veins and fractures. No consistent vein orientation to measure here. -Weiss, 4/5/95.