Very, very old tree root in peat.

We are just at the sea edge of the Ballycroy National Park here in County Mayo and walking along the beach. To the land side there is a bank of over 1.5metres of peat that makes up the coastline but no doubt it is much deeper. Here we see that the peat bogs are covering up ancient tree roots. As we know, peat can preserves such roots for millennium so I wonder just how old this tree would be? Maybe it was here when the Vikings were about or even cavemen?