The BGS Lexicon of Named Rock Units — Result Details

Barr Group

Computer Code: BARR Preferred Map Code: BARR
Status Code: Full
Age range: Abereiddian Stage (O2) — Caradoc Series (O4)
Lithological Description: Conglomerate, limestone and mudstone, shallow marine and fan delta deposits.
Definition of Lower Boundary: Drawn at the base of the Kirkland Conglomerate Formation where conglomerate with interbedded limestone rests unconformably upon igneous and metamorphic lithologies of the Ballantrae Complex.
Definition of Upper Boundary: Drawn at the conformable upward passage of the Benan Conglomerate Formation where boulder conglomerate with matrix supported clasts of basalt dolerite and gabbro pass into blue grey nodular mudstone siltstone and sandstone of the Balatchie Formation.
Thickness: c.1000m
Geographical Limits: Girvan area, southwest Scotland.
Parent Unit: Not Applicable (-)
Previous Name(s): Barr Series (-4442)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  An arcuate strip from Aldons Hills westwards to Knockburn and Laggan Hill to Laigh Letteran. See entries for constituent formations: Bevan Conglomerate Fm, Superstes Mudstone Fm, Stinchar Limestone Fm, Confinis Flags Formation, Kirkland Conglomerate Fm. 
Reference(s):
Ingham, J K, 1978. Geology of a continental margin 2: Middle and late Ordovician transgression, Girvan. "In" Bones, D R and Leake, B E. Crustal Evolution in North Western Britain and Adjacent Regions. Geological Journal Special Issue, No.10. p.163-176. 
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. 
Stone, P and Smellie, J L, 1988. Classical areas of British Geology: The Ballantrae area: a description of the solid geology of parts of 1:25 000 sheets NX 08, 18 and 19. [London: HMSO for British Geological Survey.] 
Lapworth, C, 1882. The Girvan Succession. Quarterly Journal of the Geological Society of London, Vol. 38, 537-666. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S007 S008