The BGS Lexicon of Named Rock Units — Result Details

Pont-Y-Ceunant Ash

Computer Code: PCE Preferred Map Code: notEntered
Status Code: Full
Age range: Longvillian Substage (OL) — Longvillian Substage (OL)
Lithological Description: Coarse rhyolitic tuff.
Definition of Lower Boundary: Impersistent basal Member of the Gelli-grin Calcareous Ash Formation. Conformably overlies mudstones of the Ceiswyn Formation, but base is extremely irregular.
Definition of Upper Boundary: Passes conformably and gradationally upwards into the main part of the Gelli-grin Calcareous Ash Formation.
Thickness: 0 to 6m
Geographical Limits: Bala and Corwen districts, North Wales.
Parent Unit: Gelli-Grin Calcareous Ash Formation (GEL)
Previous Name(s): Pont-Ceunant Ash (-2969)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  No stratotype defined, but the thickest development (6m) is in the area immediately south of Pont-y-ceunant, 1.5km east of Bala. 
Partial Type Section  Basal section in quarry southeast of Y Garnedd Farm. Elles, 1922. 
Reference(s):
Elles, G L. 1922. The Bala country: its structure and rock succession. Quarterly Journal of the Geological Society of London, Vol.78, 132-175. 
Bassett, D A, Whittington, H B and Williams, A. 1966. The stratigraphy of the Bala district, Merionethshire. Quarterly Journal of the Geological Society of London, Vol.122, 219-271. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable