Definitely a stone circle, very different from two other stone cricles, Gors Fwar and Bedd Arthur, in Pembrokeshire. Is it a much later date? A cairn (as marked on the OS Map) inside the circle suggest this. Looking a the large stones it is difficult to believe they were once supporting walls.
There is another unusual stone, in addition to the ‘chair’ and ‘ribbed’ stones. That is a diamond shaped one.
A beautiful, peaceful site.