The BGS Lexicon of Named Rock Units — Result Details
Bridport Sand Formation
| Computer Code: | BDS | Preferred Map Code: | BdS |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Toarcian Age (JT) — Toarcian Age (JT) | ||
| Lithological Description: | Grey, weathering yellow or brown, micaceous silt, very fine-grained sand and fine-grained sand, locally with calcite-cemented sandstone beds and lenses, variably sandy clay/mudstone at base, including Downcliff Clay (Member) of type area. | ||
| Definition of Lower Boundary: | Base of sand/silt or mudstone, as described in the Lithological Description, resting non-sequentially on limestone of the Beacon Limestone Formation or, north of Chipping Sodbury area in the Worcester Basin, a gradational boundary with mudstone of the Whitby Mudstone Formation (q.v.). | ||
| Definition of Upper Boundary: | Non sequential; base of lowest limestone (commonly sandy) of the Inferior Oolite Group resting on sand/silt or mudstone (as in the Lithological Description), or on "(Cotswold) Cephalopod Bed" (sandy and argillaceous, ironshot commonly fossiliferous limestone) in the Worcester Basin area. | ||
| Thickness: | Up to about 120 m. | ||
| Geographical Limits: | Wessex Basin to Worcester Basin (Dorset Coast to central Cotswolds, Cheltenham area). | ||
| Parent Unit: | Lias Group (LI) | ||
| Previous Name(s): | Midford Sands [Obsolete Name And Code: Use BDS]
(MS)
Yeovil Sands [Obsolete Name And Code: Use BDS] (YS) Bridport and Yeovil Sands [Obsolete Name and Code: Use BDS] (-1975) Bridport Sands [Obsolete Name and Code: Use BDS] (-1339) Cotteswold Sands [Obsolete Name And Code: Use BDS] (CTS) Upper Lias Sand [Obsolete Name And Code: Use BDS] (ULIS) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Reference Section | British Geological Survey Winterborne Kingston Borehole, Winterborne Kingston, Dorset (SY89NW/1) 927.89-1114.60 m depth. | ||
| Type Area | Broadwindsor [ST 437 026] to Burton Bradstock [SY 488 895], Dorset. | ||
| Type Section | Coastal cliff exposures (East Cliff and Burton Cliff) between West Bay [SY 465 905] and Burton Bradstock [SY 48 89], Dorset. | ||
| Reference(s): | |||
| Rhys, G H, Lott, G K, and Calver, M A. 1982. The Winterborne Kingston borehole, Dorset, England. Report of the Institute of Geological Sciences, No.81/3. | |||
| Wilson, V, Welch, F B A, Robbie, J A, and Green, G W. 1958. Geology of the country around Bridport and Yeovil. Memoir of the Geological Survey of Great Britain, Sheets 327 and 312 (England and Wales). | |||
| Cox, B M, Sumbler, M G, and Ivimey-Cook, H C. 1999. A Formational framework for the Lower Jurassic of England and Wales (Onshore Area). British Geological Survey Research Report RR/99/01. | |||
| Hesselbo, S P and Jenkyns, H C A, 1995. A comparison of the Hettangian to Bajocian successions of Dorset and Yorkshire. 105-150 in Taylor, P D (Editor). Field geology of the British Jurassic (London Geological Society). | |||
| Barton, C M, Woods, M A, Bristow, C R, Newell, A J, Westhead, R K, Evans, D J, Kirby, G A, and Warrington, G. 2011. Geology of south Dorset and south-east Devon and its World Heritage Coast. Special Memoir of the British Geological Survey, Sheets 328, 341/342, 342/343 and parts of 326/340, 327, 329 and 339. | |||
| Waters, C N, Smith, K, Hopson, P M, Wilson, D, Bridge, D M, Carney, J N, Cooper, A H, Crofts, R G, Ellison, R A, Mathers, S J, Moorlock, B S P, Scrivener, R C, McMillan, A A, Ambrose, K, Barclay, W J, and Barron, A J M. 2007. Stratigraphical Chart of the United Kingdom: Southern Britain. British Geological Survey, 1 poster. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E234 E235 E251 E265 E281 E297 E312 E327 E217 E252 E280 E341 E342 E343 E264 | |||