Exmoor Group

Exmoor Group
Stratigraphic range: Emsian (Devonian) to Tournaisian (Carboniferous)
Hangman Sandstone Formation at Glenthorne Beach, 6 km W of Porlock Weir
TypeGroup
Sub-unitsLynton Formation, Hangman Sandstone Formation, Ilfracombe Slates (Formation), Morte Slates (Formation), Pickwell Down Sandstones (Formation), Upcott Slates (Formation), Baggy Sandstone Formation, Pilton Mudstone Formation
UnderliesDoddiscombe Formation of Teign Valley Group
Thicknessabout 7000 m
Lithology
Primarymudstones,
Othersiltstones, sandstones, limestones, conglomerates
Location
RegionEngland
CountryUnited Kingdom
Extentnorth Devon to west Somerset
Type section
Named forExmoor

The Exmoor Group is a late Devonian to early Carboniferous lithostratigraphic group (a sequence of rock strata) in southwest England whose outcrop extends from Croyde in north Devon east across Exmoor to Minehead in west Somerset. The group comprises the following formations (in stratigraphic order, i.e., the oldest at the base and the youngest at the top):

  • Pilton Mudstone Formation (Pilton Beds, Pilton Shales)
  • Baggy Sandstones Formation (Baggy Beds, Marwood Beds)
  • Upcott Slates Formation
  • Pickwell Down Sandstones Formation
  • Morte Slates Formation
  • Ilfracombe Slates Formation
  • Hangman Sandstone Formation (Hangman Grits)
  • Lynton Formation (Lynton Beds, Lynton Slates)

Each of these divisions has been given different names by different authors in the past including those shown in brackets above. Some that had been classed as 'formations' (or even in one case as a 'group') are now 'members'.[1][2]

  1. ^ http://www.bgs.ac.uk/Lexicon/lexicon.cfm?pub=EXM (BGS on-line lexicon of rock units)
  2. ^ http://www.bgs.ac.uk/Lexicon/lexicon.cfm?pub=PLT (BGS on-line lexicon of rock units)