The site is formed in Upper Carboniferous Millstone Grit .
The site is shows the most extreme form and best example of ' tumbled ground ' , with innumerable small Millstone Grit blocks ( controlled by jointing ) taking up a large landslip .
The site is formed in Upper Carboniferous Millstone Grit and shows the most extreme form and best example of ' tumbled ground ' , with innumerable small Millstone Grit blocks ( controlled by jointing ) taking up a large landslip .