The BGS Lexicon of Named Rock Units — Result Details
Shales-with-Beef Member
| Computer Code: | SHWB | Preferred Map Code: | ShwB |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Sinemurian Age (JS) — Sinemurian Age (JS) | ||
| Lithological Description: | Dark grey laminated organic-rich shaly mudstone and dark grey mudstones with sporadic concretionary and tabular limestone bands. Abundant vertically oriented fibrous calcite of diagenetic origin ('Beef'). | ||
| Definition of Lower Boundary: | Base of bed 50, of Lang, W D, et al, 1923. Taken at sharp lithological change from limestone-shale interbeds of the Blue Lias Formation, to predominantly shales. Conformable boundary. | ||
| Definition of Upper Boundary: | Top of bed 75 (Birchi nodules) of Lang, W D, et al, 1923). | ||
| Thickness: | 30-32m | ||
| Geographical Limits: | Southwest Dorset and southeast Devon, United Kingdom, mapped on Sheets 326 (Sidmouth) and 327 (Bridport). Northern limit not yet proved. | ||
| Parent Unit: | Charmouth Mudstone Formation (CHAM) | ||
| Previous Name(s): | Shales-with-Beef [Obsolete Name and Code: Use SHWB]
(-1180)
Black Marl [Obsolete Name and Code: Use BVM, SHWB] (-3884) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Section | Foreshore and cliffs below Black Ven, west of Charmouth, Dorset. Lang, W D, et al, 1923. | ||
| Reference(s): | |||
| 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). | |||
| Lang, W D, Spath, L F and Richardson, W A, 1923. Shales-with-'Beef', a sequence in the Lower Lias of the Dorset coast. Quarterly Journal of the Geological Society of London, Vol.79, 47-99. | |||
| Lang, W D, 1914. The geology of Charmouth cliffs, beach and fore-shore. Proceedings of the Geologists' Association, Vol.25, 293-360. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E327 E341 E342 E343 | |||