A collapse in the earth to the north-east, along the inner edge of an ancient earthwork, has exposed what appear to be roofing stones, the telltale sign of a souterrain lying beneath. A souterrain is an underground stone-lined passage or chamber, typically associated with Early Medieval settlement in Ireland, most often used for storage, refuge, or both. They are not uncommon finds, but they are rarely announced so plainly as a hole in the ground with masonry poking through.

The souterrain sits within a ringfort, one of the thousands of roughly circular enclosed settlements built across Ireland during the Early Medieval period, roughly between the fifth and twelfth centuries. Ringforts were the farmsteads of their day, defined by one or more earthen banks and ditches, and it was common practice to dig a souterrain within the interior, accessible from inside the enclosure. At Knockane, the ringfort survives alongside this subterranean remnant, the collapsed ground along the scarp edge suggesting the passage or chamber below has partially lost its structural support over the centuries. The visible stones may represent what was once a carefully corbelled or lintelled roof, now exposed by the subsidence above it.