The area is underlain by the Upper Triassic to Lower Jurassic volcanic and sedimentary succession of the Vancouver and Bonanza Groups and the cretaceous sedimentary cover. Middle Jurassic granodioritic stocks (e.g. Rupert stock), and quartz-feldspar porphyry dykes cut the succession. Hydrothermal alterations and mineralization are associated with the porphyry dykes in the Bonanza tuffs. The succession dips gently to the southwest. The Dawson (Holberg) fault cuts the claim block uplifting Karmutsen rocks adjacent to Bonanza.