The Druids Table millstone grit rock formation at Brimham Rocks on the edge of the Yorkshire Dales, Yorkshire, England, United Kingdom, Europe

View from Derwent Edge, Peak District National Park, Derbyshire, England, United Kingdom, Europe

Salt Cellar Rock on Derwent Edge, Peak District National Park, Derbyshire, England, United Kingdom, Europe

View from Derwent Edge, Peak District National Park, Derbyshire, England, United Kingdom, Europe

View from Mam Tor Hollins Cross, Derbyshire, England, United Kingdom, Europe

Curbar Edge, Derbyshire, England, United Kingdom, Europe

Old millstones left at quarried edge of gritstone (millstone grit), Stanage Edge, Peak District National Park, Derbyshire, England, United Kingdom, Europe

Cowpers Cross, an ancient stone cross standing close to the old Roman road that crosses Ilkley moor, West Yorkshire, England, United Kingdom, Europe

A boulder of millstone grit on Ilkley moor with a perfect circular hole probably formed by a large inclusion weathered out of the bedrock, West Yorkshire, England, United Kingdom, Europe

The Thimble Stones, millstone grit boulders near the summit of Ilkley Moor, West Yorkshire, England, United Kingdom, Europe

A boulder of millstone grit on Ilkley moor with a perfect circular hole probably formed by a large inclusion weathered out of the bedrock, West Yorkshire, England, United Kingdom, Europe

A boulder of millstone grit on Ilkley moor with a perfect circular hole probably formed by a large inclusion weathered out of the bedrock, West Yorkshire, England, United Kingdom, Europe

Cowpers Cross, an ancient stone cross standing close to the old Roman road that crosses Ilkley moor, West Yorkshire, England, United Kingdom, Europe

Cowpers Cross, an ancient stone cross standing close to the old Roman road that crosses Ilkley moor, West Yorkshire, England, United Kingdom, Europe

The Thimble Stones, millstone grit boulders near the summit of Ilkley Moor, West Yorkshire, England, United Kingdom, Europe

Pendle hill from the Nick of Pendle above Clitheroe in the Ribble Valley, Lancashire, England, United Kingdom, Europe