Massive andesite of the Lower Jurassic Hazelton Group is unconformably overlain by Upper Jurassic to Lower Cretaceous Bowser Group sediments. The contact strikes west and dips 70 degrees north. The volcanic sequence is hard and resistant whereas the shales, argillites and greywacke are soft and characteristically iron- stained. The upper surface of the andesite is irregular with depressions infilled with argillite and coarse greywacke composed mainly of rounded grains of andesite. Both the volcanic and sedi- mentary rocks are intruded by light colored quartz-feldspar porphyry dikes most of which range from 1 to 3 metres in width and from 150 to 300 metres in length. They contain up to 3 per cent 0.5 to 1.5 centimetre subangular sanadine crystals. One of these dikes inter- sects a vein at the portal of an adit indicating the dike intrusions were later than the fissuring.

At an elevation of 1400 metres, an adit was driven along a quartz-arsenopyrite vein and a 13 centimetre channel sample across the vein assayed 12.3 grams gold and 1.7 grams silver (Geological Survey of Canada Memoir 223, page 69).

Mineralization in the andesite appears to have a vertical zonation. The quartz-arsenopyrite veins and stringers change to lenses of black sphalerite and pyrrhotite cut by stringers of chalcopyrite along fissured zones.