Research to document Aboriginal occupation across the Dampier Archipelago has also encountered the earliest archaeological evidence for the presence of American whalers in North West Australia. Inscriptions in the form of rock engravings made by the crews of the whaling ships Connecticut (1842) and Delta (1849) have been discovered on Rosemary and West Lewis Islands. These maritime inscriptions are uniquely superimposed over earlier Indigenous rock art motifs, appearing to represent distinct mark-making practices by the whalers on encountering an already-inscribed landscape, and thus providing insight into the earliest phases of North West Australia's colonial history.