Many theories have heen proposed to explain the origin of the distinctive ridge that runs for 3.5 km between Blakeney and Glandford in north Norfolk. These theories include an erosional remnant of a larger depositional body, an ice-marginal ridge, a crevasse filling, and a supraglacial, englacial or subglacial esker. Renewed quarrying in the Wiveton Downs Gravel Pit in the 1980s revealed that the ridge is underlain by a system of channels cut into the chalk-rich till. The stratigraphy of one channel infill indicates that meltwater streams flowed through these Nye channels and eventually overfilled them to build the ridge. This evidence, together with the undulating long profile, indicates that the ridge was formed as a subglacial esker. It is designated as a UK Site of Special Scientific Interest (SSSI) and steps are being taken to develop it as an important educational/visitor resource.