The site has been called simply "Cave" on Ordnance Survey maps since at least 1838, a name that is both matter-of-fact and slightly mysterious, given that what survives above ground looks less like any conventional cave and more like a scatter of enormous displaced roofing stones.

A souterrain is an underground stone-lined passage or chamber, typically constructed during the early medieval period and associated with nearby settlement sites, sometimes used for storage or refuge. The slabs at Kinaff are thought to represent the collapsed or exposed roof lintels of one such structure, built into the natural rise of the slope rather than excavated from flat ground. When inspectors visited in 1988, the stones were arranged in a roughly L-shaped setting, measuring around six metres north to south and three metres east to west, partially buried under sod. By a follow-up visit in 1997, the configuration had shifted in appearance: the slabs were recorded as lying in a roughly north-to-south line stretching approximately seven metres. The three principal stones are substantial, with lengths of 1.7 metres, 1.25 metres, and 1.7 metres respectively, and thicknesses ranging from 0.25 to 0.45 metres. They are separated from one another by gaps of around two metres, with a cluster of additional large stones gathered around the southernmost of the three. The 1838 map also noted a feature called "Thorn" immediately to the east of the cave marking, though this had disappeared from the later 1931 edition entirely.