The BGS Lexicon of Named Rock Units — Result Details

Nodular Limestone Member

Computer Code: NOL Preferred Map Code: NL
Status Code: Full
Age range: Homerian Age (SH) — Homerian Age (SH)
Lithological Description: Limestone, grey, buff, nodular, interbedded with green-grey, calcareous mudstone; sporadic beds of bioclastic limestone and sparse bentonitic tuffs; sparse limestone bioherms (reefs).
Definition of Lower Boundary: Gradational passage taken at the base of the first predominantly calcareous mudstone and nodular limestone overlying the bedded, limestone-dominated Lower Quarried Limestone Member.
Definition of Upper Boundary: Base of the limestone-dominated Upper Quarried Limestone Member, overlying limestone with grey calcareous mudstone partings.
Thickness: 31.1 - 37.8m at Wren's Nest, Dudley.
Geographical Limits: West Midlands.
Parent Unit: Much Wenlock Limestone Formation (WEL)
Previous Name(s): Nodular Member (-4222)
Nodular Beds [Obsolete Name And Code: Use NOL] (NOB)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Wren's Nest Geological Trail, Dudley; NCC cutting to south side of Wren's Hill Road and in associated quarry workings; locality 2 of Cutler and others, 1990. 
Reference Section  Wren's Nest Geological Trail, Dudley; locality 3 of Cutler and others, 1990. 
Reference Section  Castle Hill, Dudley; canal basin, locality CH 12 of Butler, 1939. 
Reference Section  Wren's Nest Geological Trail, Dudley; The Quarry, locality 4 of Cutler and others, 1990. 
Reference(s):
Butler, A J, 1939. The stratigraphy of the Wenlock Limestone of Dudley. Quarterly Journal of the Geological Society of London, 95, 37-74. 
Cutler, A, Oliver, P G and Reid, C G R, 1990. Wren's Nest National Nature Reserve. Geological Handbook and Field Guide. Nature Conservancy Council/Dudley MBC. 
Butler, A J, 1937. On Silurian and Cambrian rocks encountered in a deep boring at Walsall, South Staffordshire, Geological Magazine, 74, 241-257. 
Powell, J H, Glover, B W and Waters, C N, 1992. A Geological background for planning and development in the `Black Country'. British Geological Survey Technical Report WA/92/33. 
Basset, M G, 1974. Review of the stratigraphy of the Wenlock Series of the Welsh Borderlands and South Wales. Palaeontology, 17, 745-777. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E167 E168 E154