The result is a site with a shallow V-shaped profile, half earthen bank on the flat, half dry-stone wall clinging to exposed bedrock above, as though two different builders had met in the middle and agreed to differ.

The geological feature at the centre of all this is Rosky Hill, a waulsortian mudmound, a type of ancient limestone reef formed in warm shallow seas during the Carboniferous period, hundreds of millions of years before any human put a stone on top of it. Prehistoric communities in the Lee Valley near Tralee appear to have found these reef outcrops significant, because an almost identical complex sits 385 metres to the west. At Rosky Hill, the main enclosure bank on the lower, improved ground is a substantial 7.5 metres wide at its broadest point, though it has been largely flattened over time and survives to only 0.48 metres externally. As it transitions onto the south-facing slope of the reef, the bank narrows to around 1.2 metres and shifts entirely to stone, incorporating the protruding bedrock into its fabric. Inside the enclosure, where the flat ground meets the rising slope, a low stone cairn just 2.2 metres in diameter and 0.22 metres high sits in a curiously deliberate position. Beyond the enclosure itself, further stretches of stone bank meander along the upper southern edge of the reef and down its eastern slope, the longest measuring 7.5 metres. Michael Connolly examined this complex as part of his 2008 doctoral research at University College Cork on prehistoric settlement in the Lee Valley, and it is his careful landscape reading that draws out how purposefully these features engage with the geology beneath them.