The BGS Lexicon of Named Rock Units — Result Details

Lias Group
Computer Code: LI Preferred Map Code: Li
Status Code: Full
Age range: Rhaetian Age (TR) — Aalenian Age (JA)
Lithological Description: Predominantly grey, well bedded, marine calcareous mudstone and silty mudstone; thin tabular or nodular beds of argillaceous limestone, particularly in the lower part; thicker units of siltstone and sandstone, particularly in the upper part, and ironstone, particularly in the middle part. Marginal limestone facies also occur.
Definition of Lower Boundary: In some areas, markedly non-sequential on Penarth Group; at base of Blue Lias Formation, Scunthorpe Mudstone Formation or Redcar Mudstone Formation (q.v.).
Definition of Upper Boundary: Commonly an eroded surface at the base of lowest limestone or sandstone of the Inferior Oolite Group, Ravenscar Group or Dogger Formation.
Thickness: To c.1300m
Geographical Limits: Onshore and offshore United Kingdom, including Northern Ireland (see Cope, J C W, et al, 1980).
Parent Unit: Not Applicable (-)
Previous Name(s): Lias Group (Formerly Lias) (-363)
Lias (-2903)
Lyas (-3524)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Fulbeck Airfield Borehole F/B5 (SK95SW/17), top to 117.65m depth. 
Reference Section  Copper Hill Borehole, depth 17.31 to 202.11m. 
Type Area  North Yorkshire and Cleveland. 
Reference Section  Dorset coastal sections. Callomon, J H and Cope, J C W, 1995; Hesselbo, S P and Jenkyns, H C, 1995. 
Reference Section  Felixkirk Borehole. 18.09-299.15m. Includes base of the Lias Group (Report of the Institute of Geological Sciences, 83/11). 
Reference Section  Primary Reference section: North Yorkshire and Cleveland coastal sections. Powell, J H, 1984; Rawson, P F and Wright, J K, 1995; Hesselbo, S P and Jenkyns, H C, 1995. 
Type Section  On the north-east Yorkshire coast from Redcar, southwards to Blea Wyke Point. Does not include the base of the Lias Group. 
Reference(s):
Cox, B M, Sumbler, M G and Ivimey-Cook, H C, 1999. A Formational framework for the Lower Jurassic of England and Wales. British Geological Survey Research Report No. RR/99/01. 
Callomon, J H and Cope, J C W, 1995. The Jurassic geology of Dorset. 51-103 in Field Geology of the British Jurassic. Taylor, P D (Editor). (Bath: The Geological Society). 
Rawson, P F and Wright, J K, 1992. The Yorkshire coast. Geologists' Association Guide, No.34. 
Cope, J C W and others, 1980. A correlation of Jurassic rocks in the British Isles. Part 1: Introduction and Lower Jurassic. Special Report of the Geological Society of London, No.14. 
Hesselbo, S P and Jenkyns, H C A, 1995. A comparison of the Hettangian to Bajocian successions of Dorset and Yorkshire. 105-150 in Taylor, P D (Editor). Field geology of the British Jurassic (London Geological Society). 
Strickland, H E and Buckman, J, 1844. "In" Murchison, R I. Outline of the geology of the neighbourhood of Cheltenham. 
Kellaway, G A and Welch, F B A, 1948. Bristol and Gloucester district, 2nd edition. British Regional Geology. 
Townsend, J, 1813. The character of Moses established for veracity as an Historian recording events from the Creation to the Deluge, p.106, 130, 153, 275. Bath and London. 
Brandon, A, Sumbler, M G and Ivimey-Cook, H C, 1990. A revised lithostratigraphy for the Lower and Middle Lias (Lower Jurassic) east of Nottingham, England. Proceedings of the Yorkshire Geological Society, Vol.48, 121-141. 
Rhys, G H, 1974. (Compiler). A proposal standard lithostratigraphic nomenclature for the southern North Sea and an outline structural nomenclature for the whole of the (UK) North Sea. Report of the Institute of Geological Science, No.74/8. 
Arkell, W J. 1933. The Jurassic System in Great Britain. [Oxford: Clarendon Press.] 
Old, R A, Hamblin, R J O, Ambrose, K and Warrington, G, 1991. Geology of the country around Redditch. Memoir of the British Geological Survey Sheet 183 (England and Wales). 
Evans, C D R, 1983. Institute of Geological Science boreholes, 1982. Report of the Institute of Geological Sciences, No.83/11. 
Phillips, J, 1829. Illustrations of the geology of Yorkshire, p.33. York. 
Day, E C H, 1863. On the Middle and Upper Lias of the Dorsetshire Coast. Quarterly Journal of the Geological Society of London, Vol.19, 278-297. 
Wilson, V and others, 1958. Geology of the country around Bridport and Yeovil. Memoirs of the Geological Survey of Great Britain. 
Gaunt, G D, Fletcher, T P amd Wood, C J. 1992. Geology of the country around Kingston upon Hull and Brigg. Memoir of the British Geological Survey, sheets 80 and 89 (England and Wales). 
Woodward, H B, 1893. The Jurassic rocks of Britain. 3. The Lias of England and Wales (Yorkshire excepted). Memoir of the Geological Survey of Great Britain. 
Powell, J H, 1984. Lithostratigraphic nomenclature of the Lias Group in the Yorkshire Basin. Proceedings of the Yorkshire Geological Society, Vol.45, p.51-57. 
Rastall, R H and Hemingway, J E, 1939. The Blea Wyke Beds and the Dogger at Peak, Yorkshire. Geological Magazine, Vol.76.p.362-372. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E081 E127 E169 E043 E115 E049 N35 E055 E065 E064 E072 E089 E090 E091 E047 E103 E128 S013 E132 E148 E172 E175 E189 E204 E142 E237 S071 S080 S071 S081 S044 S044 S043 S081 S051 S070 S052 S052 S060 E281 S344 E341 E342 E343 E217
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