Mandy Ewington was strolling along the seashore when she looked up and saw two bones poking out of the cliff face.
She took a picture of the leg bones and sent them to leading coastal archaeologist Karl-James Langford.
Mr Langford, 39, said ‘I thought she must have been mistaken but I went down to see for myself and thought: “Bloody hell, this is amazing!”
‘You can clearly see a grave has been eroded into the sea.
‘What is fascinating is you can see the two femurs being slowly revealed as the cliffs are eroded away.’
University lecturer Mr Langford said Monknash, in South Wales, was a burial ground for Cistercian monks in the Middle Ages.
There was a monastic community close to the area and these bones indicate a male in their late 20s who was in good health.
‘I would say they belong to a monk from the 1200s – due to previous archaeological digs in the past, the depth of the bones in the cliff and the history of the area.
‘He would likely be buried with nothing except two shroud rings which would have held his burial shroud in place at the head and feet.
‘It’s quite an easy picture to put together.
‘The valley is named after the Welsh saint Cewydd and was home to a community of Cistercian Monks from 1129 until the dissolution of the monasteries in 1535.