The BGS Lexicon of Named Rock Units — Result Details

Bullhead Bed

Computer Code: BLHB Preferred Map Code: notEntered
Status Code: Index Level
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 0.3m 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 0.5m thick, but in parts of North London it is up to 1.5m thick, with an average of about 1m (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., 2012. The stratigraphical framework for the Palaeogene successions of the London Basin, UK. British Geological Survey Open Report OR/12/004. Available from http://nora.nerc.ac.uk/17121/. 
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