Kettleness was the site of one of the alum quriies which worked this coast in the 18th and 19th centuries. The shales was quarried, piled into a conical pyre with alternate layers of brushwood and set alight. The oil content in the shale allowed the pyre to smoulder away for months. The burned shale was then boiled in vats of human urine until the alum salts crystallised out: it was an important fixative in cloth dying. The quarrying left the coast hereabouts looking rather strange: in places Kettleness looks almost lunar.
Above: gutters carved out of the local sandstone for carried runoff into the sea.
There's not much left of the working to see - foundations like these, and they are eroding quickly.
View over some of the ruins, Runswick Bay in the distance.
This arch leads into a low stone-lined tunnel that runs into the hillside (purpose unknown).