The BGS Lexicon of Named Rock Units — Result Details

Ffairfach Group [Obsolete Name And Code: Use FFG]

Computer Code: FFA Preferred Map Code: notEntered
Status Code: Index Level
Age range: Abereiddian Stage (O2) — Abereiddian Stage (O2)
Lithological Description: Grits, pebbly sands, flags and grits, rhyolitic ashes and lavas,rhyolitic conglomerates.
Definition of Lower Boundary: Drawn at the base of the Ffairfach Group where grits conformably rest upon mudstones and shales of the Bifidus Member.
Definition of Upper Boundary: Drawn at the conformable upward passage of the Ffairfach Group where rhyolitic conglomerates are overlain by current bedded sandstones of the Llandeilo Flags Formation.
Thickness: 160 metres max.
Geographical Limits: Ffairfach, near Llandeilo, Dyfed.
Parent Unit: Not Entered (?)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Area around Ffairfach, Dyfed. 
Reference(s):
Williams, A, 1953. The geology of the Llandeilo district, Carmarthenshire. Quarterly Journal of the Geological Society. Vol.108, p.180, Maps. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable