Coflein has this to say:
Stone circle defined by 4 upright rectangular slabs and a further 6 recumbent slabs with two recumbent at the center. The circle is 14 m in diameter with the average stone size being 0.5 m tall, 0.34 m wide and 0.12 m thick. The circle is situated in a very wet area close to Llyn Cwmffynon. The surviving uprights are tilting and loose. K. Laws, Engineering Archaeology Services, 30th January 2005.
coflein.gov.uk/en/site/284656/images/DYFFRYN+MYMBYR%2C+STONE+CIRCLE/
No way ! nicely found
I think we owe it to ourselves and Coflein to visit this, don't you reckon?
I certainly do
On the ever-expanding list. What would we do without em?
Might make for inclusion in an unorthodox Glyder Fawr/Fach walk, although the south face may be a bit dull compared with the north.
I always wondered why there aren't more circles in Snowdonia, it's not like the area isn't inspiring, I reckon there's probably more but they're all ruined and made of small stones. once again well found, and curse my stupid computer.
Bet they're all under the reservoirs :-/
Seriously? That's a stone circle. Well I never...
By the way there is a great standard southern circuit of the main Glyderau which will pass right by this. Expect pictures from you soon....
Oh, and it would also get you the incomparable Castell-y-Gwynt. A proto-temple if ever I saw one.
That all sounds nicely promising, cheers!