Plague stones are found around the country, usually in the form of hollowed out stones or boulders. They are relics of when plagues spread through the country in medieval times. Stone boulders with hollowed out depressions or sometimes the bases of crosses were filled with vinegar and placed at or near parish boundaries. Vinegar was used as a disinfectant in the hope that the community could buy food and other goods without fear of contagion. The residents placed coins in the hollows to pay outsiders for goods or food which were left by the stone, hopefully avoiding the spread of the deadly disease. One of the most notable is at Eyam in Derbyshire, and were others at Dorchester, Penrith, Bury St Edmunds, Gresford, and Hereford. The Ackworth plague stone on the road to Pontefract dates from 1645.