The Montgomery showing occurs in rocks of the Lower Jurassic Unuk River Formation, Hazelton Group. Mineralization consists of malachite, pyrite and molybdenite hosted by fine to medium-grained andesitic tuff. This andesitic tuff has been intruded by a barren monzonitic porphyry. A network of quartz veinlets within the an- desitic tuff have been reported to occur adjacent to the mineralized area (Personal Communication, J.M. Britton).