Stac a' Chaisteal

About

When accurate plans were created as part of the STAC project, it became clear that the building is virtually identical to the "blockhouse" structures hitherto found in Caithness, Sutherland, Orkney and Shetland. This type of structure usually consists of a massive sub rectangular wall with intra mural galleries built across barring promontories, with a central defended entrance and less substantial buildings behind. It is thought to be a fore-runner of the broch; their design eventually being adapted to form massive walls in a complete circle. Although none have been excavated, it is thought to be of the period.200BC-200AD.

The survey also found evidence of earlier oval buildings running underneath the blockhouse, and a bee-hive shieling built over them.