The Beale's Quarry lies within metamorphosed sedimentary rocks ascribed to the Alexander Terrane. The Alexander Terrane is a fragmented belt dominated by plutonic rocks of the Coast Plutonic Complex. The Paleozoic to Tertiary Coast Plutonic Complex consists predominantly of crystalline rocks which exhibit a variety of fabrics ranging from pre-to post-kinematic. Interspersed within the plutonic complex are Paleozoic(?) paragneisses, younger deformed metasediments and volcanics related to the Stikinia Terrane.

A 180 to 300-metre wide vertically dipping bed of limestone extends northwestward for 1.6 kilometres from the head of a lagoon on the south side of Cunningham Island, 10 kilometres east-northeast of Bella Bella. The limestone lies within a roof pendant of greenstone enclosed in foliated granite and quartz diorite of the Coast Plutonic Complex. The limestone is intruded by mafic dikes and sills and the occasional tongue of granite, which become less common to the northwest.

The bed is comprised of white to bluish white coarse grained high calcium limestone that is occasionally siliceous and locally contaminated with serpentinite. Pyrite is formed near some of the dikes. The limestone tends to also contain streaks of disseminated pyrite on the east side of the deposit. A chip sample taken over a 30 metre width contained 54.59 per cent CaO, 0.23 per cent MgO, 1.00 per cent SiO2, 0.18 per cent Al2O3, 0.22 per cent Fe2O3 and 0.02 per cent sulphur (CANMET Report 811, p. 176).

Limestone was produced from two quarries and an underground chamber near the head of the lagoon on Lot 1333 between 1923 and 1934 (owned by J.F. Beale) and during 1948 and 1949. Between 1927 and 1949, 94,424 tonnes of limestone were quarried for the pulp mill at Ocean Falls.