The BGS Lexicon of Named Rock Units — Result Details
Nant-Ysgollon Mudstone Formation
| Computer Code: | NYG | Preferred Map Code: | NyG |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Wenlock Epoch (SW) — Wenlock Epoch (SW) | ||
| Lithological Description: | Mudstones. | ||
| Definition of Lower Boundary: | Overlies the pale grey-green mudstones of the Dolgau Mudstone Formation. | ||
| Definition of Upper Boundary: | Overlain by thinly bedded mudstones and siltstones of the Nantglyn Mudstones Formation. | ||
| Thickness: | 30 to 125 m. | ||
| Geographical Limits: | Northern and central Wales. | ||
| Parent Unit: | Not Applicable (-) | ||
| Previous Name(s): | Nant-Ysgollen Shales [Obsolete Name and Code: Use NYG]
(-2348)
Pegwn Mudstones [Obsolete Name and Code: Use NYG] (-1098) Wenlock Shales (-933) Nant-Ysgollen Mudstone Formation [Obsolete Name and Code: Use NYG] (-4819) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Tarannon area near Llanbrynmair, side stream off the Afon Cwm celch, southwest of Ffridd yr Ystrad (hill). Wood, 1906. | ||
| Reference(s): | |||
| Davies, J R, Fletcher, C J N, Waters, R A, Wilson, D, Woodhall, D G and Zalasiewicz, J A, 1997. Geology of the country around Llanilar and Rhayader. Memoir for 1:50 000 Geological Sheets 178 and 179. | |||
| Wood, E M R. 1906. On the Tarannon Series at Tarannon. Quarterly Journal of the Geological Society, London, Vol.62, 644-701. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E179 E136 E164 E150 E120 E137 | |||