Lime kiln in Riddings Wood, Casterton, Cumbria.
Lime kilns, built from the 17th to 19th centuries, were furnaces designed for the burning of limestone. This burning process produces quicklime which was used as agricultural fertiliser and for the production of building mortar. Kilns are set into the side of low hills so that carts could deliver and easily drop limestone and firewood into them. To prevent the kilns themselves from burning, they had to be lined with sandstone. It was a gruelling and dangerous job with many fatalities.