The BGS Lexicon of Named Rock Units — Result Details
Drosgol Formation
Computer Code: | DRF | Preferred Map Code: | notEntered |
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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 Group [Obsolete Name and Code: Use DRF]
(-2765)
Drosgol Beds [Obsolete Name and Code: Use DRF] (-4621) Drosgol Grits [Obsolete Name and Code: Use DRF] (-4622) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
none recorded or not applicable | |||
Reference(s): | |||
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.]. 148pp. | |||
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. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
E149 |