The BGS Lexicon of Named Rock Units — Result Details

Lenham Formation

Computer Code: LNM Preferred Map Code: notEntered
Status Code: Full
Age range: Miocene Epoch (NM) — Miocene Epoch (NM)
Lithological Description: Ferruginous sands, brightly coloured red, pink, yellow, orange and pale grey, fine-grained, micaceous and glauconitic. Beds of small, black, well-rounded, flint pebbles near base. Commonly occurring as infills of dissolution pipes in Chalk. Marine origin, disturbed by dissolution of the underlying Chalk.
Definition of Lower Boundary: Unconformable on rocks of the White Chalk Subgroup, commonly preserved in dissolution hollows.
Definition of Upper Boundary: Surface.
Thickness: c.3m
Geographical Limits: Restricted to the North Downs northeast of Lenham, Kent, above +180m OD.
Parent Unit: Residual Deposits Group (RESID)
Previous Name(s): Lenham Beds (-3536)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Overgrown abandoned brickpit near Friningham, Kent. Worssam et al., 1963. 
Reference(s):
Prestwich, J. 1858. On the age of some sands and iron-sandstones on the North Downs, with a note on the fossils, by S.V. Wood. Quarterly Journal of the Geological Society, Vol.14, 322-335. 
Reid, C. 1890. The Pliocene deposits of Britain. Memoir of the Geological Survey. 
Worssam, B C. 1963. Geology of the country around Maidstone. Memoir of the Geological Survey of Great Britain, Sheet 288 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E288