The BGS Lexicon of Named Rock Units — Result Details

Hafod Ifan Limestone Member

Computer Code: HDL Preferred Map Code: HDL
Status Code: Full
Age range: Rawtheyan Stage (OW) — Rawtheyan Stage (OW)
Lithological Description: Bluish-grey biosparite largely comprising cystoid fragments.
Definition of Lower Boundary: Unconformable on various Caradoc formations.
Definition of Upper Boundary: Succeeded by siltstones and sporadic thin sandstones of the Hwylfa Formation.
Thickness: 2.3 metres. Lateral variations 0 - 2.5 metres.
Geographical Limits: Not defined.
Parent Unit: Hwylfa Formation (HWY)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Area  Corwen, Sheet 120. 
Campbell, S D G. 1983. The geology of an area between Bala and Betws-y-Coed, North Wales. Unpublished PhD Thesis, University of Cambridge. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: