The BGS Lexicon of Named Rock Units — Result Details

Bullhead Bed

Computer Code: BLHB Preferred Map Code: notEntered
Status Code: Full
Age range: Thanetian Age (GT) — Thanetian Age (GT)
Lithological Description: The Bullhead Bed usually comprises well-rounded flint gravel ranging in size and shape to cobbles and fine boulders of unworn nodular flint, within a dark greenish grey or black glauconitic sandy clay or clayey sand matrix. The flint nodules (the 'bullheads'), which can be up to 0.3 m in diameter, are characteristically green-coated. Fossils derived from the Chalk occur in places.
Definition of Lower Boundary: none recorded or not applicable
Definition of Upper Boundary: none recorded or not applicable
Thickness: The Bullhead Bed is generally up to 0.5 m thick, but in parts of North London it is up to 1.5 m thick, with an average of about 1 m (Newman, 2009, p.18).
Geographical Limits: none recorded or not applicable
Parent Unit: Base Bed Member (BSBD)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
Curry, D. 1958. Part 3a XII Palaeogene. Lexique Stratigraphique International. Whittard, W F, and Simpson, S (editors). Vol. 1 Europe (Paris: Centre Nationale de la Research Scientifique.) 
Aldiss, D T. 2014. The stratigraphical framework for the Palaeogene successions of the London Basin, UK. British Geological Survey Open Report, OR/14/008. 95pp. 
Newman, T. 2009. The impact of adverse geological conditions on the design and construction of the Thames Water Ring Main in Greater London, UK. Quarterly Journal of Engineering Geology and Hydrogeology 42, 5-20. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E223 E241 E274