What makes it quietly anomalous is not just its scale but its ambiguity: this kind of linear earthwork resists easy classification, sitting somewhere between a fosse (a defensive or boundary ditch), a hollow-way (a sunken track worn into the ground by centuries of foot and animal traffic), and something whose original purpose has simply been forgotten.

The 1900 revision of the six-inch Ordnance Survey map recorded the feature as a fosse running approximately 80 metres before turning and continuing for around 150 metres, giving it a distinctive angled course rather than a straight line. About 1.5 kilometres to the north-west, a comparable broad deep trench runs immediately north of, and parallel to, a townland boundary, which suggests that features of this kind in the area may have had a role in marking or enforcing territorial divisions, though whether the Baurnafea earthwork shares that function is not certain. A modern roadway, running roughly north to south, has cut straight across the earthwork, and only the section to the east of that road now survives intact. The western portion has been lost, leaving the remaining stretch as a partial record of something whose full extent and original intention remain open questions.