A fosse is simply a ditch, often dug to reinforce a raised earthwork and make any approach more difficult. The combination of bank and fosse is the kind of arrangement typically associated with a promontory fort, a coastal defensive enclosure that uses a natural headland on two or three sides and a man-made barrier to close off the landward approach. The difficulty here is that no one has yet confirmed what these remains actually are.

As of 2003, when researcher Casey recorded the site, the earthworks had not been visited on the ground. The assessment at that point was cautious: the bank may simply be too slight to have ever functioned as a defensive structure, and the classification as a promontory fort remains tentative. Adding a further layer of quiet strangeness to the site, a circular enclosure at the lowest point of the island is recorded as having been used as a burial ground. Circular enclosures of this kind appear across Ireland in various forms and periods, from early medieval ecclesiastical sites to prehistoric monuments, and without closer examination it is not possible to say how old this one is or what relationship, if any, it bears to the earthworks above it.