Coflein description of this Iron Age hillfort sited upon the coast – ar lan y Mor – beside Cardiff International Airport.... not in Cardiff, of course, but at Porthkerry, Rhoose:
‘An enclosed trapezoidal area measuring 230m (N-S), 250m along N, tapering to 120m on S (4.1ha) is defended on the S by cliffs and elsewhere by three close-set banks and accompanying ditches well preserved on the W but reduced to terraces on the other three sides. Entrance on W side.
The camp occupies a blunt promontory, opening onto level ground to the west. Excavations behind the western ramparts, in 1968, identified a sequence of three rectangular buildings, occupied up to the late third or fourth century CE. Early twelfth century pottery occurred in the topsoil.‘