Bluecap
The bluecap is a mine spirit of the Northumberland and Durham coalfields (Anglo-Scottish border), seen as a small blue flame that worked as a supernatural putter hauling loaded coal tubs. It expected a putter's wage left in a corner, accepting no more or less, and could lead miners to rich seams or warn of cave-ins. At Shilbottle Colliery it was also called the Blue Bonnet.