Rock in Heptonstall
The splendidly named Hell Hole Quarry near Heptonstall was the destination for twelve members of the general public who joined West Yorkshire Geology Trust enthusiasts for a short walk on Saturday 1st July. A tough, gritty sandstone (Millstone Grit) was quarried for building stone and probably taken down the hill to build the mills along the Calder Valley, as well as being used in earlier times for the buildings in Heptonstall village. The exceptionally high quarry face shows large-scale cross-bedding, which tells geologists that the sand was deposited in a large river channel about 320 million years ago. In Heptonstall village, it is easy to see that stone roofs, flagstones, houses, church, stone setts and the headstones in the graveyard, were made from this high quality dimensional sandstone.