At the Mount Broadwood showing, a 22 metre thick phosphatic interval occurs within a cyclic, overturned sequence of sandstone, siltstone and shale in the Permian Johnson Canyon Formation (Ishbel Group). The base of the sequence and formation is marked by a 30 centimetre thick phosphatic and chert conglomerate that contains 3.80 per cent P2O5 (Open File 1987-16). A number of beds containing phosphate nodules in amounts up to 40 per cent by volume occur in this section. These beds are 1 metre or less thick and contain less than 2 per cent P2O5. The sequence unconformably overlies cherty dolomite of the Pennsylvanian Kananaskis Formation (Spray Lakes Group).