Are they two ringforts built in close proximity, or something rather more complicated? The question is not purely academic. What looks, on one level, like a straightforward double ringfort may actually preserve the ground plan of an Anglo-Norman ringwork castle, a type of fortification built not from stone but from earth and timber, consisting of a roughly circular enclosure defended by a bank, ditch, and scarp rather than a masonry tower.

The southern enclosure, a roughly circular platform around 25 metres in diameter, is the older presence on the maps: it appears on the 1837 Ordnance Survey six-inch edition as a simple circular monument. By the time the revised 25-inch map was drawn in 1913, the full complexity of the site had become legible. Beside the circular southern ringfort sits a D-shaped enclosure to the northeast, measuring approximately 48 metres by 45 metres, its flat side oriented to the southwest. The arrangement is telling. In a motte and bailey castle, a motte is the raised mound carrying the main fortification, while the bailey is an adjoining enclosed courtyard; here, the outer enclosing bank of the southern ringfort also functions as the enclosing element of the D-shaped platform, a shared boundary that is characteristic of Anglo-Norman motte and bailey construction. Oblique aerial photographs taken in July 1966 confirmed this shared outer element clearly. When the site was described on the ground in 1975, the picture grew more layered still: the interior of the southern ringfort is crossed by post-medieval cultivation ridges, evidence of later agricultural use, while the northern enclosure carries a complex series of low earth and stone banks across its interior. Three further ringforts lie within 220 metres of the monument, making this corner of Corkan an unusually dense cluster of early medieval and possibly medieval earthwork activity.