Site 3776 (Indian Ocean) was reported by Brown (1983) and listed in 1985, and relates to two mythological narratives concerning the creation of Cockburn Sound and the offshore islands, especially Rottnest.

One dreamtime story was recorded by Armstrong in 1836 and the other by Moore in 1884.

Armstrong is quoted as follows:
They [the Aboriginal people] state, as a fact handed down to them from their ancestors, that Garden Island was formerly united to the main, and that the separation was caused, in some preternatural manner by the Waugal.

Moore observed in 1884:
The natives (sic) have a tradition that Rottnest, Carnac and Garden Islands once formed part of the mainland. …the ground split asunder with a great noise, and the sea rushed in between….

The ACMC (Resolution 2004/082) recently resolved to reassess and evaluate site 3776 (‘Indian Ocean’) as ‘Not a Site’ under the Aboriginal Heritage Act (1972), but further resolves that the site may be restored at any time if and when further supporting information comes to hand.

With its recent re-mapping (ACMC Resolution 2004/083), site 3776 now reaches the mean high water mark of the coastlines of Garden, Carnac and Rottnest Islands and of the corresponding mainland.