The DRD showing is underlain by rocks of the Mississippian to Triassic Cache Creek Group which, in the vicinity of Williams Lake, is dominated by marine sedimentary rocks and metabasalt. Within this assemblage is an ultramafic body composed of serpentinized dunite and peridotite. Chrysotile asbestos occurs within more competent masses of serpentinized dunite and within more strongly deformed ultamafics, now serpentinite schist. Trenching has indicated that the extent of asbestos-bearing rocks is limited and that the asbestos is of too low a grade to constitute ore.