The BGS Lexicon of Named Rock Units — Result Details

Hundleby Clay Member

Computer Code: HBC Preferred Map Code: HbC
Status Code: Full
Age range: Berriasian Age (KR) — Valanginian Age (KV)
Lithological Description: Purple-grey, brown-mottled silty clay which becomes progressively sandier towards the top. It interdigitates with the ironstone of the Claxby Ironstone Formation. Between Belchford and Hundleby it comprises "unctuous, plastic clay" throughout (Owen and Thurrell, 1968).
Definition of Lower Boundary: An erosion surface separates the mudstones of the Hundleby Clay Member from the sandstones of the Upper Spilsby Sandstone Formation in southern Lincolnshire and the Wash. In other parts of Lincolnshire (e.g. Langton, Mavis Enderby, Mardon Hill and Raithby to Hundleby), the base of the member is placed at a down-section change from mudstones (Hundleby Clay Member) to ironstone (Claxby Ironstone Formation). As a result of interdigitation, the local base of the member may be higher within the Claxby Ironstone Formation.
Definition of Upper Boundary: Downsection change from ironstones (upper part of the Claxby Ironstone Formation) to clay (Hundleby Clay Member).
Thickness: Up to c. 5.5 m
Geographical Limits: Confined to southern Lincolnshire. The northern feather edge is between Cawkwell and Stenigot according to Owen and Thurrell (1968) and the member extends to the south-east around Spilsby. It occurs in the Skegness Borehole and apparently extends below The Wash where a similar clay situated between two sandstones, occur above the Sandringham Sands Formation and below the Tealby Formation.
Parent Unit: Claxby Ironstone Formation (CI)
Previous Name(s): Hundleby Clay Formation (-307)
Hundleby Clay (-3457)
Hundleby Clay Facies (-4699)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Hundleby Owen & Thurrell, 1968 
Reference Section  East Keal Owen & Thurrell, 1968 
Reference Section  Disused railway cutting between Benniworth and Donnington-on-Bain. Casey, 1973 
Reference Section  Belchford Owen & Thurrell, 1968 
Reference(s):
Casey, R 1973. The ammonite succession at the Jurassic-Cretaceous boundary in Eastern England. In Casey, R and Rawson, P F [editors], The Boreal Lower Cretaceous [Liverpool: Seel House Press.] 
Wingfield, R T R, Evans, C D R, Deegan, S E and Floyd, R. 1978. Geological and geophysical survey of The Wash. Report of the Institute of Geological Sciences, 78/18, 32pp. 
Owen, E F and Thurrell, R G. 1968. British rhynchonelloid brachiopods. Bulletin of the British Museum [Natural History], Geology, Vol.16, 99-123. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E103 E115