That profile is not entirely natural. Somebody, at some point in the distant past, dug across it deliberately, converting the headland into a promontory fort by cutting a deep, wide fosse, essentially a defensive ditch, across that thin isthmus to isolate the promontory from the mainland and make it defensible on all sides.

Excavations carried out by O'Kelly in 1952 established the basic sequence of the site. The fosse appears to have been cut in at least two separate phases: an initial fortification at some earlier period, followed by a deliberate re-cutting of the same ditch during the late medieval period, when whoever held the headland evidently saw reason to reinforce it. What O'Kelly's work could not establish was what the fort was actually used for in its earliest phase. No evidence of occupation contemporary with that first fortification turned up during the dig, leaving the question of who built it, and why, without a clear answer. The promontory may have been a place of refuge during a threat, a territorial marker, or something else entirely. The silence of the archaeology on that point is itself telling.

Today the site is partially overgrown and continues to erode along its coastal edges, as Atlantic exposure steadily works on the headland. The fosse is still visible in the ground, and the narrow neck that once made this place worth fortifying is still apparent in the landscape, even if the details require some patience to read.