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
Type Section  Overgrown abandoned brickpit near Friningham, Kent. Worssam et al., 1963. 
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. 
Worssam, B C. 1963. Geology of the country around Maidstone. Memoir of the Geological Survey of Great Britain, Sheet 288 (England and Wales). 
Reid, C. 1890. The Pliocene deposits of Britain. Memoir of the Geological Survey. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: