Index No: NBM053630; Collected By: ; Sample Type: hand sample; Notes: Rock chip sample of altered tuff, leached, silicified ,heavily stained by reddish and yellowish brown iron oxide, weak vuggy silica texture. Rock is representative of much of upper part of ridge: leached and variably silicified (+/- local alunite), lithic-rich tuff (silicic?). Clasts are quartz-replaced fragments of unit Td(?) Many of ledges to north are gently east-dipping. -Weiss, 6/24/95.