Kyanite has been noted (Wheeler, 1965) in schists and gneisses south of Ratchford Creek and west of the headwaters of Perry River. In that area, kyanite occurs as crystals from 1 to 2 centimetres in length. Sillimanite is also present in some strata; fibrolite intergrown with biotite can comprise in excess of 10 per cent of the rock.

The schists and gneisses which outcrop in this area are part of the autochthonous cover succession, mantling the Frenchman Cup Dome.