This is probably the source of TSC’s story, as part of a report about ‘Erratic Boulder Stones at Clun’, in ‘The Antiquary’ for March 1884. I don’t know if Coflein have changed their mind, but now they call it a Standing Stone (question mark).
The Beguildy Stone; height above ground, 3ft 6in.; breadth, 4ft. 3in.; thickness – very irregular – from 12in. to 24in., thoroughly rounded at every angle. Many unsuccessful attempts have been made to remove this stone, for standing in the midst of a field, it is an obstruction to agricultural operations. At a depth of 4ft. it is said to spread out to a much greater thickness.
Its parent rock is also in the Rhayader district, though it is commonly believed to have travelled from a different direction; for the popular legend says the devil threw it from the Graig Don rocks, near Knighton, at Beguildy Church; and as a proof the marks of his hand are still pointed out upon it. One of these marks is a bowl-like depression on its upper surface 12in. diameter and 5in. deep.
Craig y Don is a steep hill above the River Teme at SO261737 (the stone is right near the river too).
