Late Pleistocene to Recent weathering of Tertiary Sooke Gabbro produced a yellow ocherous clay, or impure bog-iron ore (laterite), which has been preserved locally. It is traceable for about 200 metres along De Mamiel Creek, having an average width of about 12 metres and an exposed thickness of 1.2 metres. The deposit consists of a very fine-grained clay, with which is mixed fairly uniformly, bog-iron ore or limonite.

The deposit was of initial interest for its potential as a base in the manufacturing of coloured paints (Geological Survey of Canada Memoir 13, page 198). Later, the deposit created excitement when analysis showed that the material resembled bauxite. A typical analysis of the material is: 13.4 per cent loss on ignition, 30.7 per cent isolubles 30.0 per cent Al2O3, 23.0 per cent Fe2O3, 0.4 per cent CaO, trace titanium and nil MgO (Minister of Mines Annual Report 1923, page 269).