Coming north from our starting point of Hendy-Gwyn/Whitland, we crested the hill and Mynydd Preseli comes into view. On this landscape, megalithically speaking it's all about those mountains and it's at this point on the journey that the density of monuments kicks in.
Marked as 'Standing Stone' on the current OS map, according to Barber & Williams (Ancient Stones of Wales, 1989) it was marked as 'Burial Chamber' on the 1952 edition. Indeed, there are clearly two stones, and a very probable third one lies fallen.
The stones stand in the hedge at the back of the garden of a new-ish house called Maes-yr-Haf, utterly covered in ivy so that we were 2 feet away and didn't spot them until coming past a second time. They're a grey-white colour, one about 6ft tall, the one immediately adjacent about 4 ft tall. The fallen one lies about 15ft west under a tree in the garden.
All three lie at the perimeter of the back garden, with the two standing ones accessible from the field behind.
It's so overgrown, and now down to two stones, that it was difficult to get any clear orientation or vibe for the place, save for the way Mynydd Preseli dominated the horizon to the north.
Barber & Williams (1989) say the site is listed in the Welsh archaeological journal Archaeologia Cambrensis in 1865 (page 91) and again in 1871 (page 133-136 with illustration on page 152). It would be interesting to see if the cromlech was in a better state of repair in that illustration.
The alternative name of Arthur's Table is a straight translation of Bwrdd Arthur, (reference to the flat top look of a cromlech?), and 'Bwardd Arthur' is presumably a mis-spelling that's passed into use.
Not far from this church there is, at Cefnbrallan, a huge ruined cromlech, with its cap overturned and broken; one of the upright stones measures 64 inches in height. Whilst this was being sketched a peasant was interrogated as to its partial destruction; he could not tell us when the damage was done, but he told us in Welsh that some fifty years ago an attempt was made to further destroy the cromlech, when a dreadful storm overtook and stopped the evil worker in his misdeeds. Our informant said, that whilst the sudden storm thundered overhead, the earth shook and trembled beneath, and all the time these great and mysterious stones remained immovable.
In a field called "Parc y Bigwrn," and in Pensarn farm, in the same parish [as Gwal y Filiast], are the remains of a cromlech destroyed about sixty years ago. Two of the supporting stones are still erect, and near them lie the remains of the rest of the chamber. One of them, nearest the hedge, is 8 1/2 ft. by 4 1/2 ft., the average thickness being 3 ft. Another was broken, about sixty years ago, into two parts, and one of them removed on a sledge drawn by six horses. All that now remain are six in number, including the part of the broken stone not removed. They vary in dimensions from 7 or 8 ft. to 4 ft. in length. Their average breadth is about 3 1/2 ft.
Our informant (John Jones), a man of more than eighty years of age, has always lived close to the spot. His memory and his character for veracity are equally good, and he remembers the capstone having been shifted from the west bearer; but had been told by his seniors that it had previously been horizontal, and was known as the table. It was subsequently thrown on the ground, where it now remains.
It may be as well to give the old man's exact words: "Yr oedd chwech ceffyl yn tynu y gareg, ac yr oedd y car llusg yn rhwygo y ffordd. Yr oedd yno tua 10 o ddynion wrth y gorchwyl, ac yr oeddent yn llawn braw pan yn cyffwrdd a'r gareg." The English of which is: "There were six horses drawing the stone, and the road was rent asunder. About ten men were engaged, and they were full of awe when touching the stone."
This superstitious dread of disturbing stones of this kind was once almost universal in the Principality as well as in Brittany, and is still felt by many of the country people.
From v III of Archaeologia Cambrensis (1872) 'Notes On Some South Wales Cromlechs' by E L Barnwell.