At the Mutz Creek showing, a 3.1 metre thick section of phosphorite and phosphatic shale occurs near the base of the Jurassic Fernie Group. A conglomerate occurs at the base. These strata unconformably overlie calcareous siltstone and silty limestone of the Triassic Sulphur Mountain Formation (Spray River Group). The entire sequence is overturned and dips moderately to the west. The phosphate interval has an average of 0.68 per cent P205 across 3.1 metres (Open File 1987-16).