The BGS Lexicon of Named Rock Units — Result Details

Superstes Mudstone Formation

Computer Code: SMU Preferred Map Code: SMU
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Mudstone.
Definition of Lower Boundary: Interfingers with Benan Conglomerate. Also rests conformably on Stinchar Limestone.
Definition of Upper Boundary: Overlain/interfingers with Benan Conglomerate.
Thickness: 0 to 25m
Geographical Limits: Girvan area, southwest Scotland.
Parent Unit: Barr Group (BARR)
Previous Name(s): Didymograptus Shales (-1832)
Didymograptus Superstes Mudstones (-4889)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Benan Burn. 
Reference(s):
Lapworth, C, 1882. The Girvan Succession. Quarterly Journal of the Geological Society of London, Vol. 38, 537-666. 
Williams, A, 1962. The Barr and Lower Ardmillan Series (Caradoc) of the Girvan district, southwest Ayrshire, with descriptions of the Brachiopoda. Memoir of the Geological Society of London, No.3. 
Ince, D, 1984. Sedimentation and tectonism in the Middle Ordovician of the Girvan district, north west Scotland. Transactions of the Royal Society of Edinburgh. Earth Sciences, Vol.75 (2), p.225-237. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S008