The BGS Lexicon of Named Rock Units — Result Details

Foston Member

Computer Code: FSTL Preferred Map Code: Fst
Status Code: Full
Age range: Sinemurian Age (JS) — Sinemurian Age (JS)
Lithological Description: Grey mudstones containing laterally persistent beds of individually distinctive limestones, totalling c.10% of sequence thickness.
Definition of Lower Boundary: Base of distinctively iron-rich limestone beds (Stubton Limestones), below which mudstones (Beckingham Member) contain only rare and thin limestone beds; at 34.65m depth in type section.
Definition of Upper Boundary: In type area, at erosive base of a ferruginous bed of oolitic wackestone (Glebe Farm Bed) at the base of the Charmouth Mudstone Formation; (at 4.58m depth in type section).
Thickness: 30.07m in type section.
Geographical Limits: East Midlands Shelf; southwards the characteristic limestones pass into mudstones; northwards limestones develop in underlying Beckingham Member.
Parent Unit: Scunthorpe Mudstone Formation (SMD)
Previous Name(s): Foston Limestones (-4052)
Alternative Name(s): Ferruginous Limestone
"Ferruginous Limestone Series"
Ironstone Series
Stratotypes:
Partial Type Section  Fulbeck Airfield Borehole F/B1 (SK85SE/25), depths 0 to 17.9m. 
Type Section  Fulbeck Airfield Borehole F/B5 (SK95SW/17), depths 4.58 to 34.65m. 
Reference(s):
Sumbler, M G, 1987. Geological Notes and Local Details for 1:10,000 Sheet SK85SE (Beckingham). British Geological Survey Technical Report. 
Sumbler, M G, 1987. Geological Notes and Local Details for 1:10,000 Sheet SK95SW (Brant Broughton). British Geological Survey Technical Report. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E127 E142