It sits on the eastern side of the gorge, where the river has cut down through limestone over millennia to create the kind of dramatic natural architecture that tends to attract human attention across centuries.

The cave was one of three in the area investigated during excavations in 1938 and 1940, work later published by Gwynn and colleagues in 1942. A researcher named Dowd, writing in 1997, catalogued it under the name 'Main Earth', suggesting it was the most substantial of the group. Two trenches were opened during the investigations, one inside the chamber and a second cutting across the northern entrance. The deposits reached were only superficial, and what they yielded was modest: fragments of charcoal, oyster shell, and remains of recent fauna. Oyster shell in an inland cave is worth a moment's thought; it points to human activity, since oysters do not wander this far from the coast on their own, even if the evidence falls well short of suggesting any organised occupation or ceremony. The charcoal hints similarly at fire, but nothing more can be said with confidence from what was found.