Arthur's Stone is a Neolithic site less than 20 miles from Skirrid/Ysgyryd Fawr. The Guardian reports that apparently it so impressed CS Lewis that he was inspired that he used the image of Arthur's Stone as the stone table on which Aslan is sacrificed in The Lion, the Witch and the Wardrobe. Also they now believe the site is aligned with Skirrid/Ysgyryd Fawr. For the full article CLICK HERE
The map below shows the location of Arthur's Stone in the Golden Valley relative to Skirrid/Ysgyryd Fawr.