A term used for any small plot with low earthen banks formed around them, which were field systems of pre-Roman times in Britain and northwest Europe. These date to the Early Bronze Age (1800 BC), so it is a misnomer to attach 'Celtic' to them. Traces of these systems may still be visible where later agriculture has not removed them. The oldest examples in Britain are blocks of arable land (sometimes associated with farmsteads, hollow ways, stockades, and enclosures) divided into a patchwork of more or less square units. They are defined by lynchets at the upper and lower edges, and by slightly raised ridges at the sides. Similar fields are known from Scandinavia and the Netherlands.