Pembrokeshire erratic routes

I discovered this old map from the days when I was a research student -- back in 1963! It's based on Griffiths's work -- there are many erratic trails across the county, and not all of the traceable arratics are from the Mynydd Preseli area. Note that some very recognizeable erratics come from St David's Peninsula too......

The ice movements are "aggregate" movements -- of course, we do not know how many times erratics have been lifted and moved by ice, sometimes in directions significantly different from those shown on the map. Neither do we know how many glacial episodes are responsible for moving the erratics from source to "final resting place."