A cross dyke or cross-dyke (also referred to as a cross-ridge dyke, covered way, linear ditch, linear earthwork or spur dyke) is a linear earthwork believed to be a prehistoric land boundary that usually measures between 0.2 and 1 kilometre (0.12 and 0.62 mi) in length.[1] A typical cross dyke consists of one or more ditches running in parallel with one or more raised banks.[1] Univallate cross dykes typically have a flat-bottomed ditch while the ditches of multivallate cross dykes possess a V-shaped cross-section. A defining characteristic of a cross dyke is that it cuts across the width of an upland ridge or the neck of an upland spur.[1] Cross dykes generally occur at altitudes over 150 metres (490 ft) above mean sea level.[2]