Minister of Mines Annual Report 1922 states that a gypsite deposit occurs on the east side of the North Thompson River near Louis Creek and practically adjoins the Canadian National Railway. The area of the deposit is not very large and the average depth of the pure material is only about 0.9 to 1.2 metres. A typical sample of the gypsite analysed: 89.7 per cent gypsum (CaSO4 + 2H2O), 0.9 per cent insoluble, 0.2 per cent organic matter, 9.1 per cent carbonate of lime and trace magnesia (Minister of Mines Annual Report 1922).

The area appears to be underlain by volcanic and sedimentary rocks of the Paleozoic Harper Ranch Group.