The claims are underlain in part by a westward younging and perhaps westerly dipping succession which includes from east to west: basaltic and diabasic flows of the Pennsylvanian Sediment-Sill Unit of the Paleozoic Sicker Group; Pennsylvanian Buttle Lake Formation bedded chert, crinoidal marble, black meta-tuffaceous or argillaceous chert; and basaltic flows of the Upper Triassic Karmutsen Formation. This succession is truncated to the west by a major body of Middle Jurassic Island Intrusions granodiorite. Anomalous copper and gold is associated with pyritic fracture zones which crosscut the Buttle Lake Formation.