The area is underlain by a flat-lying sequence of intensely metamorphosed and silicified andesite flows, tuffs, agglomerates, argillites, limestone and quartzites. This sequence has been intrud- ed by sill-like body of hornblende granite of the Coast Plutonic Complex. A number of different types of mineralization have been reported. The most common type is pyrite, pyrrhotite and small amounts of chalcopyrite, molybdenite and sphalerite in argillaceous skarns. Galena, sphalerite, chalcopyrite and occasional molybdenite are contained in quartz veins averaging about 0.6 metres wide in fractures in limy sediments. Fine-grained, disseminated pyrite, chalcopyrite and bornite are associated with shear zones in volcanics. Lenses of massive magnetite in volcanics contain chalcopyrite and bornite. Molybdenite, pyrite and chalcopyrite occur in shear zones in sericitized granite. Closely spaced jointing in the hornblende granite contains sericite, quartz, molybdenite and pyrite.