Local stories reflect the feeling that sands have shifted and covered previous landscapes and towns:
The old people sometimes talk of an extensive forest called Coed Arian, 'Silver Wood,' stretching from the foreshore of the Mumbles to Kenfig Burrows [...] All this is said to be corroborated by the fishing up every now and then in Swansea Bay of stags' antlers, elks' horns, those of the wild ox, and wild boars' tusks, together with the remains of other ancient tenants of the submerged forest. Various references in the registers of Swansea and Aberavon mark successive stages in the advance of the desolation from the latter part of the fifteenth century down. Among others a great sandstorm is mentinoned, which overwhelmed the borough of Cynffig or Kenfig, and encroached on the coast generally: the series of catastrophes seems to have culminated in an inundation caused by a terrible tidal wave in the early part of the year 1607.
Kenfig Pool, near Porthcawl, Glamorgan, has a tradition attached to it. A local chieftain wronged and wounded a Prince, and the latter, with his dying breath, pronounced a curse against the wrongdoer. The curse was forgotten until one night the descendants of the chieftain heard a fearful cry: "Dial a ddaw! Dial a ddaw!" (Vengeance is coming!). At first it passed unnoticed, but when the cry was repeated night after night, the owner of Kenfig asked the domestic bard what it meant . The bard repeated the old story of revenge; but his master, to prove the untrustworthiness of the warning, ordered a grand feast, with music and song.
In the midst of the carousal the fearful warning cry was repeatedly heard, and suddenly the earth trembled and water rushed into the palace. Before anyone could escape, the town of Kenfig, with its palace, houses, and people, was swallowed up, and only a deep and dark lake or pool remains to mark the scene of disaster. In the early part of the nineteenth century traces of the masonry could be seen and felt with grappling-irons in the pool. The sands near by cover many old habitations.
I have visited Kenfig Sands a couple of times over the years. The first time was when I was looking for the scant remains of the castle in the pouring rain.
It is surprisingly easy to lose your bearings in the dunes (well it is for me anyway!) and by the time I found the castle I was 'soaked to the bone'.
There was a Time Team episode filmed at the dunes a couple of years ago.