The occurrence is on Cracroft Island near the boundary of the Coast Crystalline Belt and the Insular Belt.

The west side of the island is underlain by andesite and tuff of the Upper Triassic Vancouver Group, Karmutsen Formation which have undergone regional greenschist facies metamorphism.

The Clam Bay occurrence on the Tidewater claim (formerly the G claim), consists of disseminated chalcopyrite, bornite and pyrite in tuff and andesite. Malachite and azurite are also present.

Selected samples assayed 0.82 to 2.13 per cent copper and associated silver values range between 1.85 to 3.09 grams per tonne silver (Assessment Report 14230, Figure 2A).