A limestone lens of the Upper Triassic Brooklyn Formation forms a 120 metre high hill, 2 kilometres due south of Eholt. The lens strikes north-northeast for 600 metres and dips nearly vertical. Exposed widths vary up to 150 metres. The limestone is bounded to the west by granodiorite of the Middle Jurassic Nelson Intrusions.

The lens consists of coarse grained, white to pale blue, thick bedded, high calcium limestone that becomes siliceous and cherty towards the margins of the deposit. A few dykes intrude the limestone. A sample across a pure limestone bed on the south face of the hill contained 54.27 per cent CaO, 0.18 per cent MgO, 2.58 per cent SiO2, 0.04 per cent Al2O3, 0.38 per cent Fe2O3 and 0.01 per cent sulphur (Canada Bureau of Mines Report 811, p. 202, Sample 61).

A second lens of light grey, medium grained limestone forms a steep, 90 metre high bluff 200 metres west of Highway 3, 2.5 kilometres south of Eholt. Local concentrations of chert and other impurities are present. A sample of chips collected randomly across the top of the cliff contained 52.40 per cent CaO, 0.38 per cent MgO, 4.94 per cent insolubles, 0.38 per cent R2O3, 0.32 per cent Fe2O3, 0.03 per cent MnO, 0.04 per cent P2O5, 0.03 per cent sulphur and 41.75 per cent ignition loss (Minister of Mines Annual Report 1960, p. 143, Sample 4).