The BGS Lexicon of Named Rock Units — Result Details

Trwyn Y Fulfran Formation

Computer Code: TYF Preferred Map Code: TyF
Status Code: Full
Age range: Comley Series (EC) — St David's Series (ED)
Lithological Description: Manganiferous siltstones with fine- to medium-grained sandstones in thin to medium beds.
Definition of Lower Boundary: Underlain by coarse- to medium-grained green sandstones and interbedded siltstones of the Hell's Mouth Formation.
Definition of Upper Boundary: Overlain by coarse-grained, thickly bedded turbidites of the Cilan Formation.
Thickness: 37m
Geographical Limits: Pwllheli area, northwest Wales.
Parent Unit: Harlech Grits Group (HGG)
Previous Name(s): Mulfran Beds (-582)
Alternative Name(s): Hafotty Formation
Type Section  Trwyn y Careg-y-tir from the old manganese trials. [SH 2877 2402], eastwards onto the hillside above [SH 2885 2394]. 
Young, T P, Martin, F, Dean, W T and Rushton, A W A. 1994. Cambrian stratigraphy of St Tudwal's Peninsula, Gwynedd, northwest Wales. Geological Magazine, Vol.131, 335-360. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: