Talc is found southwest of Mount Attwood, on both sides of two large 'knockers' of Permo-carboniferous chert of the Knob Hill Group, which are contained within a Cretaceous serpentinized ultramafite body. The talc forms a three metre high bluff and generally contains disseminated magnetite, but with streaks and lenses 15 to 25 centimetres long, of pure talc (Church, 1986).