Where we do know the provenances of these erratics, they always seem to have come from the W or NW -- and it is hardly a coincidence that this coincides with the direction of ice movement of the Irish Sea Glacier. Here are just three of them, well described in the literature:
The interesting thing about these erratics, of course, is that because they are in "natural" contexts, nobody (not even the most senior archaeologist!) ever questions that they are true erratics, emplaced by natural processes. In all the cases above, they have been emplaced by glacier ice, on the English side of the Bristol Channel.
Let's move back across the Bristol Channel to Pembrokeshire. I have just caught up with Adrian James's interesting blog, in which he shows photos of many South Pembrokeshire erratics that have been carried from the NW by the ice of the Irish Sea Glacier. They are scattered about all over the place! Here are two photos of the erratics in Flimston Churchyard:
I have covered this before, in January of this year:
but a revisitation is needed. The following is adapted from Adrian's text:
Flimston Chapel churchyard (SR92399558). There is a substantial collection of erratics in this churchyard. Some have been used as headstones for the graves of members of the Lambton Family who died in military service. Others have been left sitting in one corner of the enclosure. All of these stones arrived in the churchyard when the chapel was renovated and re-consecrated in 1903. There are 7 of them. A pamphlet, which describes the features and memorials in the yard, printed at the time of the opening of the chapel in about 1914, gives us these vague details:
No. 1 Boulder, at the head of Lady Victoria Lambton's grave was taken from just opposite Flimston Cottage. A 'brecciated spherulite, albite, trachyte or rhyolite.' Many occur in Pembrokeshire. This one 'seems to fit best with those of Romans' Castle in the character of its spherulites and groundmass.'
[Flimston Cottage stood at SR927955, about 0.3 km ESE of the chapel and just north of the old clay pits.]
No. 2 Boulder, from Pwllslaughter, which stands in the opposite North corner. [Bullslaughter, SR942944 - approximately 2.25 km SE]
No. 3 Boulder from Bulliber Farm [About 2.25 km WNW, at SR905968]
No. 4 Boulder from Merrion pond. [ About 2 km NE].
No. 5 Boulder from Lyserry Farm
No. 6 Boulder from Lyserry Farm.
No.7 Boulder from Lyserry Farm.
[Lyserry is about 3.4 km ENE of Flimston chapel, at SR9556967]
Most of these appear to have travelled over 30 miles from the N. West separated from their parent rocks by St Brides Bay and Milford Haven, and by a considerable mass of high ground.........
Clearly there was some significance in dragging these rocks from their resting places about the area, but quite what the intention was is unclear. It seems likely, as I have mentioned elsewhere, that they were all intended to be memorials or headstones.
There are many other erratics featured on Adrian's Blog, but this is the most substantial of them, in the farmyard of Loveston Farm: