It is usually believed that stone cromlechs are entirely absent from Montgomeryshire. The remains of what seems to have been a fine example of a cromlech, with perhaps a long "creep" entrance, are to be seen a few yards east of a deserted cottage called Pen y Parc. A neighbouring cottage, marked upon the Ordnance sheet as 'Pen y mynydd,' is still known to the old inhabitants of the district by the name which it bears in the Tithe Schedule (no. 1105), 'Bwlch y Gistfaen.' The stones forming one side of the structure, and the covering stones, have been broken to furnish the material for the adjacent walls, and fragments still lie strewn around. The right or southern side of the avenue and chamber has also been too much disturbed to permit of accurate measurements being taken. The entire structure would appear to have measured about 21 yards in length, and to have been aligned to east and west (magnetic) - Visited, 14th April, 1910.