The White Rock quarry is situated at the south end of a 13 kilo- metre long belt of Upper Triassic Quatsino Formation (Vancouver Group) limestone. The belt, up to 3 kilometres wide, is preserved along the axis of a broad northwest plunging syncline. The quarry lies approximately 200 metres southwest of the fault contact with underlying basaltic flows of the Upper Triassic Karmutsen Formation (Vancouver Group). Limestone in the quarry is white, massive and recrystallized with an average of over 97 per cent CaCO3 content and less than 1 per cent SiO2. Brightness is 88 to 96 (green filter). Faulting is evident with up to 12 metre offsets; small crosscutting mafic and intermediate dykes are also observed.

Ideal Cement Company Ltd. began quarrying limestone here in 1987. The company currently mines 25,000 to 30,000 tonnes of limestone per year for export to the United States (H. Diggon, personal communication, 1990). Production figures are included with the Ideal Cement (092F 395) deposit.