The Monashee Complex contains orthogneisses and paragneisses which are exposed in the Frenchman Cap dome. Frenchman Cap is one of a series of domal structures, and, together with the Thor Odin, Valhalla and Pannacles domes comprises the core zone of the Omineca crystalline belt. Aphebian orthogneisses (Brown, 1980) predominate in the lowest part of the Monashee Complex, and are exposed in the core of the Frenchman Cap dome. These are overlain by an autochthonous cover or mantling succession of clastic and carbonate rocks.

Locally, kyanite may constitute 20 per cent of micaceous schists within the mantling succession, and individual crystals may be over three centimetres in length (Hoy, personal communication, 1987). North of Kirbyville Creek, on the north flank of Frenchman Cap dome pelitic horizons contain abundant, coarse kyanite, some sillimanite and locally, up to 30 per cent garnet. A distinctive amphibolite layer in the same are is reported to contain garnets ranging from 2 to 20 centimetres in size and randomly oriented clusters of kyanite (Scammell, 1985).