Jaws Gravestone in Ireland?

 'Here lies the body of Mary Lee; 

Died at the age of a hundred and three. 

For fifteen years she kept her virginity; 

Not a bad record for this vicinity.' Robert Shaw says this poem in Jaws 

The scene is here 

Spielberg asked Shaw for the author so he could get it cleared. But Shaw said as it was from a tombstone in a graveyard near him in Ireland it would not need clearance.

But I can't find a reference for the actual tombstone. Does anyone know where it might be? Shaw lived at Drimbawn House in Tourmakeady, County Mayo

It is very unlikely that would ever be written on an Irish gravestone. But some version of it might have been and then altered by local humour. Something like  'Here lies the body of Mary Lee; died at the age of a hundred and three. For all her life she kept her fidelity.'

The only Mary Lee I can find in Irish graveyards database is this one
which is in Moycullen Old Cemetery not too far from Shaw's home

Declan Moore the Archaeologist kindly visited this grave but the text is no longer legible 

  So we might never know if it is the original source of the legendary jaws gravestone.