A sample of argillite was found to bloat well upon heating and may, therefore, be of use as a light-weight aggregate in the making of concrete (Minister of Mines Annual Report 1953, page 188). At the time the sample was taken the underlying rocks were reported to be part of the Malahat volcanic group. However, the area is now mapped as the Chert-Argillite-Volcanic Unit of the Jurassic to Cretaceous Leech River Complex (Formation), (Geological Survey of Canada Map 1553A).