Several small lakes on the rolling plateau surface north of Kamloops and west of the North Thompson River contain concentrated brines in which magnesium sulphate predominates. The area appears to be underlain by argillite of the Jurassic Ashcroft Formation or Upper Triassic Nicola Group.

One of the lakes (lake 7) contained brine which analysed 20.8 per cent total solids and a specific gravity of 1.1895 at 16 degrees Celsius (October, 1937). The composition of solids assayed 84.0 per cent MgSO4, 14.7 per cent Na2SO4, 1.0 per cent Na2CO3, 0.2 per cent NaCl and trace CaSO4. The lake is slightly over 0.8 hectare in area and occupies a sharp basin-like depression. The depth of brine in the centre probably exceeds 1.5 metres; the quantity of salts in solution is approximately 725 tonnes per 0.3 metre of depth. The only crystal noted was in the form of thin films of interlocking epsomite crystals occupying depressions along the shore (Bulletin 4).

Another small lake about 2.4 kilometres to the south was sampled and analysed 6.0 per cent total solids and a specific gravity of 1.049 at 16 degrees Celsius. The composition of solids assayed 65.0 per cent MgSO4, 31.0 per cent Na2SO4, 1.4 per cent Na2CO3, 2.4 per cent CaSO4 and trace NaCl.