As you entered the Peak District, you may have seen the symbol for the National Park, which is a large circular Millstone, mounted on a stone wall.

Millstone Grit got its name because it was used for making Millstones. These Millstones were made for grinding grain into flour and for sharpening steel blades.

This type of rock is the most common rock in the Dark Peak. It was created about 300 million years ago from sand and gravel which was washed down from the high mountains in Scotland.

The mud, sand and gravel were then squashed by other rocks, which formed on top of them to make Millstone Grit. Another important rock in this area is Shale, which was also formed from mud washed down from the mountains.