Limestone was produced from two small quarries on Lot 492, 350 metres south of the east end of Priest Lake on northern Texada Island.

The Johnson Quarries are situated near the western margin of a 13 kilometre long belt of Upper Triassic Vancouver Group, Quatsino Formation limestone up to 3 kilometres wide that is preserved along the axis of a broad northwest trending syncline. The quarried limestone is the middle calcium member of the Quatsino limestone. Locally, the limestone is warped into a smaller southwest plunging syncline with a west limb striking 015 degrees and dipping 15 degrees northwest and an east limb dipping less than 10 degrees south. Two porphyritic dykes striking northeast and dipping vertically are exposed in the west quarry.

The limestone is fine-grained, dark grey to black with some light grey bands. Calcium limestone is predominant, with minor interbedded magnesian limestone. A chip sample taken across 11.6 metres of strata, in the southwest face of the west quarry, contained 52.70 per cent CaO, 1.68 per cent MgO, 1.86 per cent insolubles, 0.10 per cent R2O3, 0.16 per cent Fe2O3, 0.005 per cent MnO, 0.017 per cent P2O5, 0.06 per cent sulphur, 43.30 per cent ignition loss and 0.14 per cent water (Bulletin 40, page 78 - Sample 3).

Two small quarries were operated by Stanley Beale between 1945 and 1955.