Modern reservoir, date (1921) from Shotbolt et al, 2001. Previously piecemeal enclosure of valley below Ingbirchworth with evidence of former strip layout. 1851 and 1891 OS maps show pattern of long thin fields with sinuous boundaries along the valley of the Ingbirchworth Dike. Legibility of enclosures now invisible. Polygon contains a former sandstone quarry, Crow Slacks Quarry, which is marked on the 1851 map as active but by 1893 it is disused and shown as rough ground.