The 367 area is underlain by rock of the Lower Jurassic Unuk River Formation, Hazelton Group. These rocks consist of sandstone, wackes and shale overlain by lapilli-tuff of andesitic composition. The Brucejack fault and associated splay faults cut the country rock in a north-south to northwest direction. North of Brucejack Lake, the fault system is bounded on the east by rocks of the Lower Jurassic Unuk River Formation, Hazelton Group. A variety of Jurassic hornblende syenites and alkali feldspar syenites occur in the area.

The 367 showing is a zone of tectonically brecciated andesite with a matrix of vuggy quartz, quartz veins and carbonate veins. It occurs in a cross-fracture zone with 50-degree trend adjacent to the first north-south fault west of the Brucejack fault. The zone occurs mainly between north-south faults, crosscutting, but fading out across the fault. The breccia matrix and veins contain minor arsenopyrite and galena. The wallrock is slightly sericitized (Bridge, D. and Melnyk, W., 1982).

Refer to West (104B 193) for details of related mineralization and work history.