The Malahat deposit is located 1 kilometre northwest of Devereux Lake, near the northwestern edge of Lot 201, 24 kilometres northwest of Victoria.

A limestone lens extends northwest from the north end of a small lake for 300 metres. The lens strikes 100 degrees and dips 45 to 80 degrees south. Exposed widths vary from 18 metres on the southeast end to 76 metres on the northwest end. The lens terminates to the northwest in a series of 6 metre high bluffs. The limestone appears to continue underneath the lake, to the southeast. The lens is bounded to the southeast by the Colquitz Gneiss; the Wark Gneiss lies to the northeast. The Wark and Colquitz gneisses are thought to be metamorphic equivalents of mafic and silicic units of the Paleozoic Sicker Group, respectively; the latest metamorphism took place in the Jurassic. The limestone is intruded by a few mafic dykes up to a metre wide that tend to parallel the strike of the lens.

The lens consists of fine to medium-grained, dark bluish grey to white limestone containing the occasional film of white siliceous material. A chip sample taken across a 51.8 metre long quarry face in 1956 contained 54.1 per cent CaO, 0.24 per cent MgO, 2.3 per cent insolubles, 0.10 per cent R2O3, 0.10 per cent Fe2O3, 0.002 per cent MnO, 0.019 per cent P2O5, 0.03 per cent sulphur, 42.8 per cent ignition loss and 0.12 per cent water (Bulletin 40, page 89, Sample 4). A total of 1,424 tonnes of limestone were produced from a single quarry between 1944 and 1950.