Canmore suggests this may have been a vitrified fort, but evidence is not conclusive:
This islet is one of a small group about 300 yards NW of Dun Scaich (NG51SE 1) and about 200 yards from the shore. Its triangular crest is surrounded by the tumbled remains of a stone wall, the debris averaging from 6 to 10ft in width. As there is an unusually large proportion of small stones, the wall could not have stood very high. Here and there a foundation course of larger stones can be traced, indicating the general outline. There are indications of internal shelters against the E side. As some small lumps of stone show distinct traces of fusion by fire, it has been assumed that this has been a vitrified fort. But such pieces are loose and sporadic in occurrence and have probably been brought to the spot. The local belief is that there was once a smithy on the island.
No certain evidence of vitrifaction was seen. Visited by OS (A C) 26 June 1961