Great dolmens have up to five capstones lying on eight to twelve supporting stones. It features marble lintels and capstones and wide terraces on two sides of the house. It was surmounted by an elaborately carved cornice, and a parapet topped by capstones. There are also traces of extractions of large stone plates used as megalithic capstones. The massive capstones found in Rota were instead quarried, like the pillars. The capstones of many southern megaliths have 'cup-marks' carvings. The Knockeen Portal Tomb has five large uprights and two capstones in total. Massive boulders had been prepared as capstones. The corner and intermediate piers have moulded capstones. The covering cairn is missing but most of the capstones are still in place. The rounded capstones help prevent rats from climbing up the pillar. It consists of eleven supporting stones which carry four capstones. Standing stones and capstones cannot have any stone stack on top of it. Standing stones and capstones do not count. Above the 2 meter high chamber lie two capstones.