The burial chamber at Ty Mawr is thought to be a collapsed Neolithic burial chamber. A massive capstone slab, roughly 3.6m by 2.6m, lies sprawled across two flattened stones. These appear to have been its supporters and would have stood up to 1.3m high. There is also a 0.6m high sill-stone on the eastern side. The original OS map (1"-mile?) is said to show a cairn roughly 15m by 10m. No trace survives of such a feature.

Sources: RCAHM Anglesey Inventory (1937), 73
Lynch 'Prehistoric Anglesey' (1970), 28 fig 5

John Wiles 10.09.07