Preseli roches moutonnees.......

 

Thanks to Hugh 360 for this photo, showing very beautifully the very large roche moutonnees that dominate the northern flank of Mynydd Preseli.  On the mountainside here we can see Carn Alw, Foel Drygarn, and Carn Goedog.  This is a clear indication of ice flow from the north -- probably during the course of several glaciations.  I think the capacity for the creation of large-scale erosional features was rather limited during the Devensian -- so probably we are looking at the results of more prolonged ice inundation during the Wolstonian and Aglian glacial episodes.