The BGS Lexicon of Named Rock Units — Result Details

Hayne Beech Member

Computer Code: HYBC Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Chadian Substage (CI) — Asbian Substage (CR)
Lithological Description: Soft, light to dark grey, commonly pale weathering, siliceous radiolarian shaly mudstones, typically thin-bedded (c. 10 cm), interbedded with thin silicified limestone and chert beds and thin, mottled and dolomitized limestones at the top.
Definition of Lower Boundary: The lower boundary is taken at the incoming of thin-bedded, light to dark grey siliceous radiolarian shaly mudstones and thin limestone beds above the hard, black, finely laminated cherty mudstones of the underlying Doddiscombe Formation.
Definition of Upper Boundary: The upper boundary is taken at the incoming of abundant blocky chert with few limestones of the Kersdown Chert Member above the siliceous radiolarian shaly mudstones.
Thickness: About 40 m
Geographical Limits: Between Upcott, near Brushford (SS 90 25) and Tracebridge (ST 06 20), Somerset
Parent Unit: Bampton Limestone Formation (BPLM)
Previous Name(s): Hayne Beech Beds (-3483)
Hayne Beech Formation (-4108)
Lower Bampton Limestones (-3865)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Kersdown quarry, Bampton, Somerset. The upper c. 40 m thickness of the member is seen in the core of an anticline, along with the lower boundary of the overlying Kersdown Chert Member. Described by Whiteley (2004). 
Reference(s):
Whiteley, M J. 2004. Culm Trough. 477-504 in British Lower Carboniferous Stratigraphy. Cossey, P J, Adams,A E, Purnell, M A, Whiteley, M J, Whyte, M A and Wright, V P (editors). Geological Conservation Review Series, No 29. (Peterborough: Joint Nature Conservation Committee). 
Webby, B D. and Thomas, J M. 1965. Whitsun field meeting: Devonian of west Somerset and the Carboniferous of north-east Devon. Proceedings of the Geologists Association, Vol. 76, 179-194. 
Thomas, J M. 1962. The Culm Measures in north-east Devon. Proceedings of the Ussher Society, Vol. 1, 29-30. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable