A northwest trending mass of Upper Triassic Vancouver Group, Quatsino Formation limestone occurs just west of the Strathcona Park Boundary, 58 kilometres southwest of the town of Campbell River. The mass is up to 1000 metres wide, outcropping for 5 kilometres along the top of White Ridge. The limestone is underlain by basaltic flows of the Upper Triassic Vancouver Group, Karmutsen Formation.