This is the Duckmanton Railway Cutting Site of Special Scientific Interest, near Chesterfield, north-east Derbyshire. In the lower part of the section is the Chavery Coal, overlain by shaly mudstones containing non-marine bivalves and ostracods. This exposure of the Chavery coal was worked (illegally) by desperate miners during the 1984-85 miners' strike. (Chris Darmon, pers. comm.)

The railway cutting is a site of international geological importance, as it contains the stratotype section for the Anthracoceras vanderbeckei (Clay Cross) marine band which is the boundary between the Langsettian and Duckmantian Stages of the Carboniferous, informally the junction between the Lower and Middle Coal Measures.

The site is managed by the Derbyshire Wildlife Trust and is accessible by permit only.
www.derbyshirewildlifetrust.org.uk/reserves/duckmanton-railway-cutting