The BGS Lexicon of Named Rock Units — Result Details

Porth Trefadog Formation

Computer Code: POTRF Preferred Map Code: notEntered
Status Code: Full
Age range: Floian Age (OFL) — Darriwilian Age (ODW)
Lithological Description: Felsic ash flow tuff and tuffaceous sandstone.
Definition of Lower Boundary: Unconformably overlying Cambro-Ordovican Holy Island Group (NHI) or Llanfechell Group (LFEC) rocks.
Definition of Upper Boundary: Stratigraphic contact with Porth Swtan Formation (SWTN).
Thickness: none recorded or not applicable
Geographical Limits: Anglesey.
Parent Unit: Cemaes Group (CMES)
Previous Name(s): Cae Adda Volcanic Formation (ADDA)
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
none recorded or not applicable
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable