The BGS Lexicon of Named Rock Units — Result Details

Baggy Sandstones Formation

Computer Code: BYS Preferred Map Code: notEntered
Status Code: Full
Age range: Famennian Age (DA) — Famennian Age (DA)
Lithological Description: Interbedded brown and grey fine-grained sandstones, siltstones and greenish-grey shaly mudstones with thicker buff, fine- and medium-grained feldspathic and micaceous sugary sandstones.
Definition of Lower Boundary: The unit is conformable with the underlying Upcott Slates. The Baggy Sandstones sequence of grey and buff, fine- to medium-grained, thickly-bedded and massive sandstones, marked by local ferruginous staining is in sharp contact of cream, buff, green, grey and purple slates and silty slates of the underlying Upcott Slates.
Definition of Upper Boundary: Conformable with the overlying Pilton Shales, though no sharp formation boundary lines can be traced. The top of the Baggy Sanstones, characterised by thickly-bedded and medium-grained sugary sandstones with partings of thinly-bedded micaceous sandstone, passes transitionally into the Pilton Shales, seen typically as shales and siltstones with placed at the top of the highest of the fine- to medium-grained sugary sandstones of the Baggy Sandstone.
Thickness: To 450m
Geographical Limits: Around Barnstaple in North Devon, the outcrop runs east to west between the coast and inland, near to Dulverton.
Parent Unit: Exmoor Group (EXM)
Previous Name(s): Marwood Beds (-100)
Baggy And Marwood Slates (-1410)
Baggy Beds (-1411)
Baggy And Marwood Beds [Obsolete Name And Code: Use BYS] (BMB)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Baggy Point, North Devon, where the foreshore and cliffs expose the base and top of the formation and much of the 450m thickness. Edmonds and others, 1979. Part of the middle of the Baggy Sandstones appears to have been cut-out by faulting. 
Reference(s):
Goldring, R. 1971. Shallow-water sedimentation as illustrated in the Upper Devonian Baggy Beds. Memoir of the Geological Society of London. No.5. 
Edmonds, E A, Whittaker, A, and Williams, B J. 1985. Geology of the country around Ilfracombe and Barnstaple. Memoir of the British Geological Survey, Sheets 277 and 293 (England and Wales). 
Ussher, W A E. 1879. On the geology of parts of Devon and west Somerset, north of South Molton and Dulverton. Procedings of the Somerset Archaeological and Natural History Society. 
Edmonds, E A, Williams, B J and Taylor, R T. 1979. Geology of Bideford and Lundy Island. Memoir of the Geological Survey of Great Britain, Sheets 292 with 275, 276, 291, and part of 308 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E293 E292 E294