A Carboniferous limestone lens forming a narrow north-trending ridge outcrops over a length of 230 metres with an average width of 40 metres on the north side of the South Thompson River, 14 kilometres due east of Kamloops. The lens lies within argillite and quartzite of the Devonian to Triassic Harper Ranch Group. Possible bedding strikes 170 degrees and dips steeply east.

The deposit consists of fine grained, light to dark grey limestone with scattered patches and irregular bands of chert. A chip sample taken across a 21.3 metre wide section free of chert analysed 54.65 per cent CaO, trace of MgO, 2.2 per cent insolubles and 42.63 per cent ignition loss (Minister of Mines Annual Report 1959, page 170, Sample 1).