In effecting some improvements, a few years ago, on the farm of Ardross, it was found necessary to remove one of these cairns; but the people had a tradition that "the plague was buried under it," and refused to touch it; and it was with no small difficulty, that they were at length induced to assist in its removal.
This extract from the Rosskeen chapter of the 1834-45 Statistical Account could refer to Carn Na Feinne (which is certainly near Ardross), but I guess even if not, it gives an idea of local beliefs about cairns. There's not much of it left - just the thick slabs of sandstone and schist that made up the chamber.
In some of the cairns which were removed, sculls and bones of a very large size were found. One of these cairns bears the name of Carna nam Fiann, i.e. the cairn of the Fingalians.