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

A band of limestone 500 - 600 metres wide extends eastward from Gordon Cove along the south shore of Gillatt Arm for 2500 metres. The limestone strikes 070 degrees and dips approximately 50 degrees northwest. The bed contains minor volcanic flows or sills. A sample assayed 53.09 per cent CaO, 1.75 percent MgO, 3.22 per cent SiO2 and 41.41 per cent loss on ignition (Paulsen 1982, page 3-4).

This occurrence was briefly evaluated by Consolidated Cinola Mines in 1982 as a source of neutralizing medium for the Specogna epithermal gold prospect (103F 034).