At the Abby occurrence, a 1.5 metre thick phosphorite bed and a 0.35 metre thick phosphatic sandstone bed occur at the base of the Jurassic Fernie Group, overlying Triassic siltstone of the Sulphur Mountain Formation (Spray River Group). Overlying the phosphate horizon are phosphatic shale and shale. Phosphorite is pelletal with an average grain size of approximately 0.1 millimetre. Phosphate content of the phosphorite is 21.7 per cent P2O5 and of the sandstone, 7.43 per cent P2O5.

A sample analysed by X-ray fluorescence contained 7.56 per cent SiO2, 1.03 per cent Al2O3, 0.51 per cent Fe2O3, 0.40 per cent MgO, 46.99 per cent CaO, 0.30 per cent Na2O, 0.15 per cent K2O, 0.07 per cent TiO2, 0.01 per cent MnO, 31.15 per cent P2O5, 1.06 per cent sulphur, 2.97 per cent total carbon and 10.82 per cent ignition loss (Fieldwork 1989, page 490).