Limestone is exposed in the vicinity of the BB group of claims on Silver Creek, just north of its confluence with Vital Creek, 160 kilometres northwest of Fort St. James (see 093N 014).

The deposit lies within a 200 kilometre long, northwest-trending belt of massive Permian-Pennsylvanian limestone with minor chert and argillite assigned to the Carboniferous to Jurassic Cache Creek Complex. The limestone is bound to the east by the north-northwest striking Pinchi fault zone and overlain to the west by a sequence of chert, argillite, quartzite and greenstone (andesite) also assigned to the Cache Creek Complex. Locally, the belt is up to 760 metres in width.

The limestone is variably dolomitized along the Pinchi fault zone due to hydrothermal alteration. A sample of blue-grey limestone outcropping on the BB claims analysed 55.46 per cent CaO, 0.27 per cent MgO, 0.11 per cent SiO2, 0.20 per cent Fe2O3+Al2O3 and 0.41 per cent insolubles (Geological Survey of Canada Memoir 252, page 36, sample 14).