The BGS Lexicon of Named Rock Units — Result Details

Red Marl Group [Obsolete: use FWW]

Computer Code: RDM Preferred Map Code: notEntered
Status Code: Full
Age range: Pridoli Epoch (SO) — Pragian Age (DP)
Lithological Description: [Obsolete: use FWW] Red siltstones and mudstones with subordinate sandstones. Correlative of Red Marl Group is the Milford Haven Group.
Definition of Lower Boundary: Drawn at base of green-yellow sandstones of Green Beds where they rest unconformably on sandstones and siltstones of Ludlow age.
Definition of Upper Boundary: Drawn at conformable upward passage from red marls to green and red sandstone of the Senni Beds.
Thickness: 1100m approx.
Geographical Limits: South Wales and Gloucestershire.
Parent Unit: none recorded or not applicable
Previous Name(s): Red Marl [Obsolete Name and Code: Use MMG, RDM] (-4292)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  May Hills, Gloucestershire. 
Reference(s):
Strahan, A and others, 1909. South Wales District-Pembrokeshire. Summary of Progress of the Geological Survey of Great Britain, for 1908, p.33. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E232 E246 E245 E244 E234