Several limestone lenses of the Upper Triassic Nicola Group are exposed on the south slope of Promontory Hills. The lowest lens forms the top of a steep bluff 335 metres above Highway 8. Siliceous dark grey limestone veined with white calcite is exposed across 21 metres for 61 metres along a strike of 040 degrees. A sample taken across the width of the exposure analyzed 0.92 per cent Fe2O3, 0.107 per cent MnO, 1.06 per cent MgO, 45.92 per cent CaO, 0.042 per cent P2O5, 0.04 per cent S, 36.85 per cent Ig. Loss, 0.08 per cent H2O, 2.84 per cent R2O3 and 13.32 per cent Insol. (Minister of Mines Annual Report 1958). A second lens is found 91 metres higher up the hill, a third lens 152 metres higher and a fourth lens 91 metres above the third. All lenses form bare northeast trending mounds on flat terraces that break the general slope of the hill.