Index No: NBM055820; Collected By: ; Sample Type: hand sample; Notes: Rock chip sample of silicified bedded tuff with complete silica replacement, from unmarked shallow decline on south flank of Sleeping Butte. Essentially 100% replacement, probably originally opal, now chalcedony, red, white, clear, and gray. Relict quartz phenocrysts and pumice holes can be seen. Ledge trends ~N65E, 35NW. -Weiss, 4/7/95.