The west face of a nunatak, Barbican Mount, contains porphyritic between the X and Bear Run glaciers contains porphyritic dacite flows intercalated with black limy argillite and slate of the Upper Triassic Tats Complex. Pyrite, pyrrhotite and chalcopyrite have been reported from this face. A sample of a calcite vein containing sulphides within a dacite unit, ran 3.7 grams per tonne silver, 955 parts per million copper, and 60 parts per billion gold.