Grovesend Formation

Late Carboniferous (Westphalian)

Lithology
Predominantly argillaceous, comprising mudstones and siltstones, with well developed coals; minor lithic ("Pennant") sandstones.

Upper Boundary
The Grovesend Formation is the youngest unit found in the Forest of Dean coalfield. It is overlain unconformably by sandstones of the Sherwood Sandstone Group in the Newent Coalfield, and either the Sherwood Sandstone or Mercia Mudstone groups in the Bristol/Somerset Coalfields.

Lower Boundary
The base is placed at the base of the Brazilly Seam.

Representative Sites
Oakenhill Railway Cutting
Blackpool Brook

Information on lithology and boundaries taken from the British Geological Survey Lexicon of Named Rock Units
and BGS Memoirs.