The BGS Lexicon of Named Rock Units — Result Details

Drybrook Sandstone Group [Obsolete Name And Code: Use CHSA]

Computer Code: DS Preferred Map Code: notEntered
Status Code: Index Level
Age range: Arundian Substage (CJ) — Holkerian Substage (CQ)
Lithological Description: Sandstone with subordinate shale of Lower Drybrook Sandstone and finer grained sandstone with wind blown quartz of Upper Drybrook Sandstone divided by calcareous Drybrook Limestone.
Definition of Lower Boundary: Drawn at base of Lower Drybrook Sandstone where it rests conformably on the Whitehead Limestone. (Correlative of Whitehead Limestone - Clifton Down Mudstone). (Correlative of Lower Drybrook Sandstone - Lower Cromhall Sandstone).
Definition of Upper Boundary: Drawn at unconformable upward passage from Upper Drybrook Sandstone to quartzitic sandstones of the Quartzitic Sandstone Group or Trenchard Group of the Coal Measures. (Correlative of Upper Drybrook Sandstone - Middle Cromhall Sandstone.
Thickness: About 230m
Geographical Limits: Forest of Dean, Gloucestershire, West of River Severn.
Parent Unit: none recorded or not applicable
Previous Name(s): Upper Drybrook Sandstone [Obsolete Name And Code: Part Of CHSA] (UDS)
Lower Drybrook Sandstone [Obsolete Name And Code: Part Of CHSA] (LDS)
Drybrook Limestone (-874)
Alternative Name(s): none recorded or not applicable
Type Area  West of River Severn, Chepstow. 
Trotter, F M, 1942. Geology of the Forest of Dean and Iron-ore Field. Memoir of the Geological Survey of Great Britain. 
Welch, F B A and Trotter, F M. 1961. Geology of the country around Monmouth and Chepstow. Explanation of one-inch geological sheets 233 and 250. Memoir of the Geological Survey of Great Britain. 
Sibley, T F. 1912. The Carboniferous succession in the Forest of Dean Coalfield. Geological Magazine, Vol.49, p.417. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E234 E233