Both were dolmens, a form of megalithic tomb in which a large flat capstone is raised on upright supporting stones to create a covered chamber, and both had Irish names that outlasted them. One was called Clogan-carneen, the other Mainsair Asal, which translates roughly as the Asses' Manger.

What we know of them comes largely from two sources cited by the antiquarian William Borlase in 1897, and before him from a 1802 account by Tighe. Clogan-carneen was a substantial structure: its capstone measured around fifteen feet long, eight feet broad, and twenty inches thick, supported on six or eight upright stones set into a natural cavity in the hillside, raising it some three feet off the ground. Beneath it, a space had been hollowed out and floored with stones. The monument was destroyed at some point, and when the capstone was broken up, a heap of bones was found inside, along with teeth that resembled those of pigs. Tighe also noted a cavity on the hill roughly a hundred yards above, speculating that this might have been the original quarry from which the capstone had been dragged and slid into position. The second monument, Mainsair Asal, was a smaller square enclosure formed by four large upright stones with two more stones laid across as a roof; by the time it was recorded, three or four of the side-stones had already been removed. Its entrance was set at an angle rather than straight on, and digging inside had reportedly turned up human bones. The ground around it was noticeably raised. Both structures are now gone, leaving only the hollows and the names. Nearby, a stone-lined well and a lime kiln, used historically for burning limestone to produce agricultural quicklime, still mark the location.