A mill driven by a horizontal waterwheel in which paddles are secured to the lower end of an upright shaft and which drives a runner stone directly above it without any gearing. It is usually driven by a jet of water from an orifice or steeply-sloping trough. There is a considerable variation of detailed design. It can have a number of features, among which are See TIRL. See TUB WHEEL. See also NORSE MILL, GREEK MILL, CLICK MILL, SHETLAND MILL and SALTKVARN (Scandinavian).