Geograph - photograph every grid square

Duckmanton railway cutting is on a long dismantled railway line of the old Lancashire, Derbyshire & East Coast Railway (LD&ECR) from Chesterfield to Lincoln. It was proposed by William Arkwright, a descendant of the industrial pioneer Sir Richard Arkwright. William owned the Sutton Scardale estate Link.
The railway opened in 1897 with two large tunnels at Duckmanton and Bolsover. A history can be found here Link
Since closure the National coal board have infilled the tunnel but not the cutting. Thankfully it has become a geological SSSI under management of the Derbyshire wildlife trust. Split into two sections by a blocked road bridge Link. The most eastern side has little exposures but the old Great Central railway and site of Arkwright colliery can be seen. Crossing the road and walking down the steps into the main bulk of the reserve to the west of the bridge.
Muds, sand stones, seat earths and coal are exposed well along this cutting. All dipping at a steep angle in a NW-SE trend, this is because of the Brimington anticline. A large 'buckle' of strata that exposed the seams at the surface.
Not only is that good but an important title of GSSP or a global stratigraphic section and point has been given. Meaning this location determines the boundary between certain lengths of time. This example being boundary the between the Duckmantion and Langsettian sub ages of the Carboniferous. Bivalve fossils date to 311.7ma. The marine band in question is the Vanderbeckei, correlated throughout the coalfield, the last major marine band before the huge economic deposits of coal. The change from seat earth to coal then marine and non marine bands are evidence for sea level rise, common in a period of ice ages.
Entering the cutting is by permit only.