Fourteen sequences of land snails were sampled by corer from the Emily Bay settlement site and four from Cemetery Bay. Thirty-nine samples of modern land snails were collected from six environmental zones on Norfolk Island. The modern fauna is depauperate compared to the prehistoric one, with loss occurring mostly among the larger species. We suggest this is due first to predation by Rattus exulans introduced by prehistoric Polynesians and later to habitat loss following European settlement. We consider we cannot use the land snail data to make any interpretation of direct human impact on the Norfolk Island environment. We note however that the density and diversity of snails is high in the prehistoric cultural layer and below it, showing that the settlement area probably provided a more vegetated and wetter environment for the earliest settlers than is now present.