They have been labelled "Caves" on Ordnance Survey maps since at least 1840, a name that quietly undersells what they actually are: a carefully constructed souterrain, built by human hands rather than shaped by water and limestone. Souterrains are underground passages or chambers, typically of early medieval origin, associated with nearby settlements and thought to have served as places of refuge, cool storage, or concealment. This one is more architecturally varied than most.

The structure consists of two linked chambers. The first is rectangular, measuring roughly 4.76 metres by 1.87 metres, with a ceiling height of 1.85 metres, its roof formed by two large stone lintels. A low connecting passage, or creep, just 0.59 metres high, leads northeast into a circular chamber nearly 2.75 metres in diameter, whose roof was once constructed in a corbelled, beehive style, each ring of stones projecting slightly inward until they met at the top. The walls throughout are partly cut directly into the bedrock and partly built up in drystone. The original entrance, now partially collapsed, faced the riverbank at the northwest end of the rectangular chamber. Access today is through a breach in the north wall of the circular chamber. To the south, a heavily overgrown depression some eight metres long and four metres wide may indicate a third chamber that has since fallen in. The 1840 Ordnance Survey map depicted the site within a hachured enclosure, suggesting a surrounding earthwork was still legible at that time; by the 1916 edition the enclosure had disappeared from the record. A separate enclosure survives about twenty metres to the west, across the river.