The BGS Lexicon of Named Rock Units — Result Details
Drosgol Formation
| Computer Code: | DRF | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Pending Upgrade | ||
| Age range: | Hirnantian Age (OH) — Hirnantian Age (OH) | ||
| Lithological Description: | Dark grey, brown to buff weathering, massive, homogenous mudstones with thick beds of sandstone locally, and evidence of penecontemporaneous slumping and dewatering. | ||
| Definition of Lower Boundary: | Conformably overlies the Nant-y-Moch Formation, the boundary being either gradational or sharp, and taken at the point where thinly interbedded mudstones and sandstones give way to massive mudstones. | ||
| Definition of Upper Boundary: | Taken at the top of the well bedded Pencerrigtewion Member, where it gives way to massive disturbed mudstones of the Bryn-glas-Formation, the boundary being gradational and apparently conformable, although likely to be a syndepositional slide plane. | ||
| Thickness: | 290 to 405m | ||
| Geographical Limits: | Not specified. | ||
| Parent Unit: | Not Available (!) | ||
| Previous Name(s): | Drosgol Beds [Obsolete Name and Code: Use DRF]
(-4621)
Drosgol Grits [Obsolete Name and Code: Use DRF] (-4622) Drosgol Group [Obsolete Name and Code: Use DRF] (-2765) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| none recorded or not applicable | |||
| Reference(s): | |||
| Jones, O T. 1909. The Hartfell-Valentian succession in the district around Plynlimon and Pont Erwyd (north Cardiganshire). Quarterly Journal of the Geological Society of London, Vol.65, 463-536. | |||
| Cave, R, and Hains, B A. 1986. Geology of the country between Aberystwyth and Machynlleth. Memoir of the British Geological Survey, Sheet 163 (England and Wales). (London: HMSO). 148 pp. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E149 | |||