Today Chris and I managed to find the Gernos Fach ring cairn which various people (including Hugh, I think) have mentioned in the past. It's not easy to find, in a wilderness of gorse patches, boggy areas and stony litter, but if you use the above images and work from the corner of the enclosed land to the north, you'll find it. Grid reference: SN078345.
There is no mention of this site on the Coflein records.
See this post:
The bank is relatively dry and grass-covered, whereas the centre of the ring is more boggy with rushes and sphagnum. The southern part of the bank is more or less intact, a metre or so wide, about 50 cms high, and with abundant stones breaking the surface. At the "entrance" on the eastern rim there are two larger dolerite stones or gatekeepers, and a rough arrangement of smaller stones that seem to suggest a passage or causeway running up to the entrance from the east. To the south of this stone setting there appears to be a double bank -- what was this all about? The northern semi--circle is largely absent, but a few traces of it can still be seen maybe 20 cms above the general level of the turf.
Was the whole feature abandoned before it could be finished? Did it have a wooden palisade on top of the bank, maybe with the purpose of containing animals? It's too big to be a hut circle, but is it a utilitarian feature or a ceremonial one? How old is it?
Answers on a post-card please. Hugh knows far more about these circular structures than I do -- his comments will be welcome.