This is an intact cromlech in a beautiful and enchanting place.
Although built as a Preseli dolmen in the Carreg Samson style (smallish, enormous fat capstone), because of its location this feels unlike any other site I've been to. Megalithic sites tend to have such a grand sense of place, so clearly built into their landscape with the horizons and far contours in mind. This place, though, is secluded, standing near the top of a steep riverbank above the Afon Taf.
The sense of intimacy is not just to do with the relatively confined landscape, but in a large part it's the woods too. It stands in a small clearing among old mixed woodland, in a possibly deliberate perfect circle of beech trees.
The builders worked among trees like those around it today, and all the construction and usage took place to a soundtrack of the riverflow, continuous from before they first came until after we leave.
This setting profoundly triggers the imagination because so many ancient monuments must have been built in woodland. West Kennett longbarrow was built in an oak forest, not the monoculture agri-desert we know today.
For so many Preseli cromlechs to be built with a seaward orientation, it's got to be the river that is the focus of this one. The apparent entrance faces SSW down to the river.
The three side uprights are about 4 and a half feet high, the fourth, at the back, is smaller but even with the extra width of the capstone at that point there's still a clear uptilt to the entrance.
A single outlier stone, presumably displaced from the cromlech, stands 3 ft high and 5 ft long about 5m to the north.
According to Children & Nash (1997), in 1872 Barnwell wrote that the chamber and capstone were still covered by a mound and at least 32 outer kerbstones were visible. However, given the scarcity of covered barrows in the region and the serious work that would've had to have taken place in the last 130 years to get it to its present bare state, I'm tempted to suggest Barnwell was either exaggerating or confused in his description.
This really is a beautiful mesmerising site, do make the effort to visit.
Below Gwal-y-Filiast the Afon Taf snakes through a wooded valley, and in the river is a naturally created hollow called Crochan Arthur (Arthur's cauldron).
Wirt Sikes mentions it in 'British Goblins' (1880):
This [feature] is under a cromlech at Dolwillim, on the banks of the Tawe, and in the stream itself when the water is high; it is a circular hole of considerable depth, accurately bored in the stone by the action of the water. This hole is called Arthur's Pot, and according to local belief was made by Merlin for the hero king to cook his dinner in.
Perhaps Arthur kept his dog in Gwal-y-Filiast (the lair of the greyhound bitch) to keep her out of the way while his dinner was stewing.
"I visited this gorgeous little cromlech in May 2010 during my 3 day tour of South West Wales. It's a dramatic part of the country, with both mountainous regions and spectacular coastlines. It also just happens to have a concentration of prehistory equal to anywhere in the country. A burial chamber called Gwal-y-Filiast or 'The Grayhound's Kennel' is one such place and a fine example to boot!"