The BGS Lexicon of Named Rock Units — Result Details
Laundry Mudstone Formation
| Computer Code: | LYMD | Preferred Map Code: | LdM |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Hirnantian Age (OH) — Aeronian Age (SA) | ||
| Lithological Description: | Mudstone, silty, grey, weathers buff, bioturbated, thinly interbedded with sandstones (< 15cm). The basal few metres comprise beds of fine-grained sandstone about 0.5m thick. | ||
| Definition of Lower Boundary: | The lower boundary is marked by the change in lithology from the underlying Powys Castle Conglomerate. | ||
| Definition of Upper Boundary: | Upper boundary gradational with pale grey-green mudstones of the Dolgau Formation. | ||
| Thickness: | 160 to 170m | ||
| Geographical Limits: | Widespread on the Welshpool sheet (151) west of the river Severn. Also occurs in the south of Oswestry (137), in the Meifod area and in the north of Montgomery (165). | ||
| Parent Unit: | Not Available (!) | ||
| Previous Name(s): | V2 Beds [Obsolete Name and Code: Use LYMD]
(-3546)
Llwyn-Y-Brain Formation [Obsolete Name And Code: Use LYMD] (LYM) |
||
| Alternative Name(s): | Fron Frys Formation |
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| Stratotypes: | |||
| Type Area | Laundry Lane, Guilsfield; several smaller quarries on the north side of the lane. | ||
| Reference(s): | |||
| King, W B R. 1928. The geology of the country around Meifod, Montgomeryshire. Quarterly Journal of the Geological Society of London, Vol. 84, 671 - 704. | |||
| Cave, R and Dixon, R J, 1993. The Ordovician and Silurian of the Welshpool area. In Woodcock, NH, Bassett, MG. (eds.) Geological Excursions in Powys, Central Wales. University of Wales Press, National Museum of Wales, Cardiff. | |||
| Cave, R. 1965. The Nod Glas sediments of Caradoc Age in North Wales. Geological Journal, Vol. 4, 279 - 298 | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E137 | |||