Together these elements cover roughly 1.76 hectares, enclosed within ramparts that run approximately 200 metres from east to west and at least 88 metres north to south. What makes the site quietly remarkable is not its height but its position: early maps record the surrounding low-lying land as marshy, which would have made the reef read as a promontory in the landscape, accessible by dry ground only from the east. The marshy ground to the south may itself have served as a natural defence, which would explain why only a single rampart survives there.

The site came to fuller archaeological attention in the late 1990s when the Office of Public Works commissioned trial excavations ahead of construction of a new N22 link road between Ballycarty Cross and the Killarney road. The work was described in detail by Michael Connolly, County Archaeologist for Kerry, in a 1999 report. The reef itself is Waulsortian limestone, a distinctive Carboniferous formation noted for an unusually dense concentration of fossil material within its minimal soil cover. Connolly observed that the ramparts, built largely by scarping back into the natural breaks in the reef's slope, are continuous along the western half of the spur but become intermittent and harder to read toward the east. Sod-stripping during excavation revealed a rampart at the western end that had previously left no surface trace, suggesting the gaps in the eastern stretches may conceal further buried features. The ditch between the two northern ramparts averages 3.73 metres in width but is only 0.3 to 0.4 metres deep, most likely filled over time with material slipped from the inner rampart. From the spur's central position, two fording points on the River Lee and the principal passes through the flanking Stacks Mountains and Slieve Mish ranges would all have been visible, which goes some way toward explaining why someone judged this particular outcrop worth enclosing so carefully.