The lower two members of the Kunga Group, consisting of the Upper Triassic Sadler and Peril formations, represent the main limestone resource of the Queen Charlotte Islands, particularly the basal massive grey limestone comprising the Sadler Formation. Its thickness varies from less than 30 metres to more than 200 metres.

The Kunga Group, consisting of the limestone members and an overlying argillite member, rests conformably on the Karmutsen Formation, and may be overlain conformably by the Jurassic Maude Group or disconformably by the Middle Jurassic Yakoun Group.

The limestone outcrops along the south shore of Gillatt Arm, immediately west of Gordon Cove for 1300 metres. The beds strike 090 degrees and dip 50 degrees north. Drilling indicates the limestone is at least 29 metres thick. Limited surface examinations suggest the deposit contains a resource of 1.5 to 8 million tonnes of limestone that can be quarried from surface (Paulsen, 1982, page 3-7). The bed consists of dark grey to white, medium to coarse-grained limestone with minor quartz. It is cut by calcite veins and a few narrow fault breccia zones. Three drill holes averaged 51.96 per cent CaO, 0.12 per cent MgO and 4.73 per cent SiO2 (Assessment Report 16566). A surface sample assayed 54.50 per cent CaO, 1.91 per cent MgO, 1.25 per cent SiO2 and 42.44 per cent loss on ignition (Paulsen 1982, page 3-6). City Resources completed three diamond-drill holes in 1987 to test this limestone as a source of neutralizing medium for the Specogna epithermal gold deposit (103F 034).