A trachytic unit of alkali-feldspar porphyry, lithic tuff, tuff breccia and pyritic schist is structurally underlain by quartz-sericite schist, chlorite schist and interlayered meta- sediments of the Devonian to Mississippian Eagle Bay Formation.

A surficial deposit of bog manganese (wad) occurs as a subsoil deposit, of variable grade and thickness (up to 3 metres) over a 1200 metre northwest trend. The material is very hetero- geneous, comprising mainly rock fragments in a light to dark brown earthy ground mass consisting largely of limonite with small localized patches of wad. Assays up to 53 per cent manganese are reported (Annual Report 1929-224).

Higher on the hillside occurs a zone of altered rock mineralized with pyrite and siderite with minor mangano-siderite associated with calcite and quartz. Rocks of this type may have been the source of the manganese oxides.