The BGS Lexicon of Named Rock Units — Result Details
Moelfryn Mudstones Formation
| Computer Code: | MFN | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Pending Upgrade | ||
| Age range: | Ashgill Series (OA) — Ashgill Series (OA) | ||
| Lithological Description: | Pale grey, brown-weathering burrow-mottled mudstones with thin siltstone and locally, sandstone beds. A thin, muddy, bioclastic limestone member [Rhiwlas Limestone] occurs at the base of the Formation in places. | ||
| Definition of Lower Boundary: | Unconformable on various Caradoc formations. | ||
| Definition of Upper Boundary: | Conformably overlain by the Foel y ddinas Mudstone Formation, but in the Corwen District is unconformably overlain by the the sandstones and siltstones of the Bron-y-graig Formation. | ||
| Thickness: | To 900m | ||
| Geographical Limits: | none recorded or not applicable | ||
| Parent Unit: | Not Applicable (-) | ||
| Previous Name(s): | Maerdy Mudstone Formation [Obsolete Name And Code: Use MFN]
(MAE)
Rhiwlas Mudstones [Obsolete Name and Code: Use MFN] (-1690) Moelfryn Mudstone [Obsolete Name and Code: Use MFN] (-4791) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| none recorded or not applicable | |||
| 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. | |||
| Alder, K E. 1976. The geology of an area around Bettws Gwerfil Goch and Melin-y-Wig. Unpublished PhD Thesis, University of Cambridge. | |||
| 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: | |||
| E136 E120 | |||