The BGS Lexicon of Named Rock Units — Result Details

Denbigh Grits Group [Obsolete: use DG]

Stratotypes:
Computer Code:	DFG	Preferred Map Code:	notEntered
Status Code:	Full
Age range:	Wenlock Epoch (SW) — Wenlock Epoch (SW)
Lithological Description:	[Obsolete: use DG] Poorly sorted greywackes with siltstones and mudstones. (Correlative of Denbigh Grits, Pen-y-Glog Grits of Dee Valley.
Definition of Lower Boundary:	Drawn in passage sequence where pale grey mudstones and siltstones of Llandovery age give way upwards to the darker greywackes, siltstones and mudstones of Denbigh Grits Group.
Definition of Upper Boundary:	Drawn at conformable upward passage from greywackes, siltstones and mudstones of the Denbigh Grits Group to yellow and grey banded mudstones of the Lower Nantglyn Flags.
Thickness:	1100m.
Geographical Limits:	North-east Wales (Clwyd).
Parent Unit:	none recorded or not applicable
Previous Name(s):	Denbigh(shire) Grits [Obsolete Name and Code: Use DFG] (-3988) Fynddog Grits [Obsolete Name and Code: Use DFG] (-4602)
Alternative Name(s):	none recorded or not applicable
Type Area	Denbigh Moors, Clwyd.
Reference(s):
Boswell, P G H. 1926. A contribution to the geology of the eastern part of the Denbighshire Moors. Quarterly Journal of the Geological Society, Vol. 82, p. 562.
Hughes, T McK. 1879. The Silurian rocks of the Vale of Clwyd. Quarterly Journal of the Geological Society, Vol.35, p.695.
Ramsay, A C. 1866. The geology of North Wales. Memoir of the Geological Survey of Great Britain, Vol.3,
Murchison, R I. 1958. Sandstones and grits, a lithological variety of lower portion of the Wenlock Formation. Siluria, p.116. London.
Cummins, W A. 1957. The Denbigh Grits: Wenlock greywackes in Wales. Geological Magazine, Vol.94, 437-451.
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable

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