The BGS Lexicon of Named Rock Units — Result Details

Highworth Grit Member

Computer Code: HWGR Preferred Map Code: HwG
Status Code: Pending Upgrade
Age range: Oxfordian Age (JO) — Oxfordian Age (JO)
Lithological Description: Cross-bedded yellow, orange and white sand and sandstone, sparsely ooidal, with pebbles, very rare ammonites, passing down into clayey sand. Sandy ooidal limestone locally developed.
Definition of Lower Boundary: Base is marked by an upward passage from grey to brown variably sandy mudstone (Highworth Clay Member) or from sandy ooidal limestone (Pusey Flags Member) into sand or sandstone with ooids of the Highworth Grit Member.
Definition of Upper Boundary: Top is a non-sequence, may be bored or eroded. Change up from sand and sandstone of the Highworth Grit Member into bedded bioclastic or ooidal limestones of the Stanford Formation.
Thickness: 2 to 3m in the type area, 1.2m at Lamb and Flag Quarry, c.3.7m at Westbury and Wootton Bassett.
Geographical Limits: North Wiltshire to southwest Oxfordshire. Best developed in the area of Highworth and Hatford. Might be represented at Spirt Hill, near Calne, Wiltshire (Arkell, 1951).
Parent Unit: Kingston Formation (KTON)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Shellingford Crossroads Quarry, Faringdon, Oxfordshire. Highworth Grit partially and poorly exposed. Wright in Wright and Cox, 2001. 
Reference Section  Lamb and Flag Quarry, Kingston Bagpuize, Oxfordshire Base of Highworth Grit was formerly exposed here. Wright in Wright and Cox, 2001. 
Reference(s):
Wright, J K, and Cox, B M. 2001. British Upper Jurassic Stratigraphy (Oxfordian to Kimmeridgian). Geological Conservation Review Series. No. 21. (Peterborough: Joint Nature Conservation Committee/Chapman and Hall.) 
Arkell, W J. 1939. Map of the Corallian Beds between Marcham and Faringdon, Berkshire. Proceedings of the Geologists' Association, Vol.50, 487-509. 
Arkell, W J. 1951. The geology of the Corallian ridge between Wootton Bassett and Lyneham, Wiltshire. Wiltshire Archaeological and Natural History Magazine, Vol.54, 1-18. 
Arkell, W J. 1941a. Map of the Corallian Beds around Highworth, Wiltshire. Proceedings of the Geologists' Association, Vol.52, 79-109. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E253