The word Stiperstones comes from “stripped-stone” an effect caused during the last Ice-Age, a geological abnormality that is unique to Britain.” ~ Michael Raven
(Y Carneddau Tuon – The Dark Rocks)

The Stiperstones is a wild ridge of Quartzite tors surrounded by a sea of heather located south-west of the county town of Shrewsbury and offers panoramic views of the Shropshire Hills Area of Outstanding Natural Beauty. But the mystery and fear generated by the serrated skyline led to some sinister associations in the past.

Shropshire has more than its fair share of giants. There is a Giant’s Chair on Titterstone Clee, but the feature with the same name found on the Stiperstones has become known as the Devil’s Chair.
The story is that the devil came over from Ireland with a leather apron full of stones either to block the Hell Gutter, a ravine on the side of the hill, or to dam the River Severn. He sat down to rest on what became the Devil’s Chair and when he got up his apron strings broke and the great stones were scattered all around.
Whenever he can, the devil flops into the chair so that his weight can help push down the Stiperstones since he believes that if they sink into the earth, England, a country he hates, will perish. If anyone else dares to sit in his chair a thunderstorm will immediately erupt.

Mary Webb (author 1881-1927) wrote in her book ‘The Golden Arrow’
Nothing ever altered its look. …it remained inviolable, taciturn, evil. It glowered darkly in the dawn, it came through the snow like jagged bones through flesh…
source: The Folklore of Shropshire by Roy Plamer, printed by Logaston Press
BTW Google spell-check wants to replace Stiperstones with superstitions – how spooky is that?