The BGS Lexicon of Named Rock Units — Result Details

Sylvan Limestone Formation

Computer Code: SYLV Preferred Map Code: Syl
Status Code: Full
Age range: Asbian Substage (CR) — Brigantian Substage (CX)
Lithological Description: Limestone (typically rubbly calcrete) with subordinate mudstone and sandstone, and basaltic lava(s) including the Little Wenlock Basalt.
Definition of Lower Boundary: The lower boundary is taken at the base of lowermost limestone resting, probably unconformably, on sandstone/mudstone sequence of the Lydebrook Sandstone Formation.
Definition of Upper Boundary: Upper boundary taken at conformable base of lowermost sandstone of the overlying Pennine Lower Coal Measures Formation (where present). Elsewhere unconformable junction with overlying mudstone and sandstone of the Pennine Lower Coal Measures Formation.
Thickness: Full thickness of 19.68m at stratotype but c.105m in expanded section of Little Wenlock Basalt at Little Wenlock [SJ 6470 0700].
Geographical Limits: Lilleshall [SJ 73 15], Coalbrookdale [SJ 64 08], Little Wenlock, [SJ 6470 0700].
Parent Unit: Peak Limestone Group (PKLM)
Previous Name(s): Upper Limestone And Lower Limestone (-1853)
Carboniferous Limestone [Obsolete entry, see Supplementary Information] (-4550)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Little Wenlock, west of Little Wenlock Fault (Sheet 152). Scattered small sections described by Hamblin, R J O and Coppack, B C, p.21-23, 1995 
Reference Section  Lilleshall Borehole L18 (SJ71 NW/64), New House Farm, Lilleshall 14.94m - 34.44m depth. 
Reference(s):
Riley, N, 1998. Lilleshall Borehole L18 Lithology Log. British Geological Survey Technical Report WH/98/90R. 
Riley, N, 1998. Correlation of selected Ove Arup Boreholes. (Lilleshall). British Geological Survey Technical Report WH/98/91R. 
Prestwich, J, 1840. On the Geology of Coalbrookdale. Transactions of the Geological Society of London, Series 2, Vol.5, 413-495. 
Hamblin, R J O and Coppack, B C, 1995. Geology of Telford and the Coalbrookdale Coalfield. Memoir of the British Geological Survey, parts of Sheets 152 and 153 (England and Wales). 
Whitehead, T H, Robertson, T, Pocock, R W and Dixon, E E L. 1928. Geology of the country between Wolverhampton and Oakengates. Memoir of the Geological Survey of Great Britain, Sheet 153 (England and Wales). 
Bridge, D M and Hough E, 2002. Geology of the Wolverhampton and Telford district. Sheet Description of the BGS Sheet 153 (England and Wales). 
Murchison, R I, 1839. 'Silurian System'. [London: John Murray.] 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E153