The Poett Nook showing is located on the south shore of Numukamis Bay, on the west side of Barclay Sound.
Two limestone bands of the Upper Triassic Quatsino Formation (Vancouver Group), up to 250 metres in width, extend westward for up to 1750 metres. The bands are separated by a mafic flow or sill. This sequence is overlain by black limestone and argillite of the Upper Triassic Parson Bay Formation (Vancouver Group). Bedding strikes 123 degrees and dips 65 degrees southwest.