Oxford Limestone Member
Oxford Limestone Member is part of the Alston Formation
Known alternatively as the Greenses Limestone. See Frost and Holliday (1980); Burgess and Holliday (1979); Day (1970); Fowler (1926); George and Black (1971); Gunn (1900); Gunn and Clough (1895).
Limestone, thick bedded at base, becoming thin bedded at top; grey to dark grey with numerous red-weathered Osagia (an alga) haloes; particularly rich in corals and brachiopods.
The type section is near Broomlee Lough, Northumberland (NY 7903 6990 and 7960 7041). Frost and Holliday (1980, p. 32) noted this locality in the grey to dark grey fossiliferous limestone with Osagia (‘Girvanella’) haloes, which is 5–6 m thick in the Bellingham district (Figure 11, Column 3).
Lower and upper boundaries
The lower boundary is taken at the generally conformable, sharp base of the first bed of limestone that overlies measures of the Alston Formation. This typically displays a coal or seatearth immediately below the limestone.
The upper boundary of the member is taken at the top of the uppermost limestone bed that is overlain by a coarsening upwards sequence of dark grey mudstones, siltstone and sandstone, the first containing ironstone nodules.
Between 5 and 6 m.
Distribution and regional correlation
Widespread limestone member occurring throughout the Northumberland Trough in northern England and the Scottish Borders within the Alston Formation, stratigraphically lying below the Eelwell Limestone (Figure.12, Column 1–4; Figure 13, Column 3). Some authors correlate the Oxford Limestone with the Jew Limestone of the Alston Block and north of the Lake District (George and Black, 1971) and with the Bridge Limestone in the Bewcastle and Langholm area (Day, 1970) (Figure 10, Column 3; Figure.11, Column.2).
- Frost, D V, and Holliday, D W.1980.Geology of the country around Bellingham.Memoir of the Geological Survey of Great Britain, Sheet 13 (England and Wales).
- Burgess, I C, and Holliday, D W.1979.Geology of the country around Brough-under-Stainmore.Memoir of the Geological Survey of Great Britain, Sheet 31, parts 25 and 30 (England and Wales).
- Day, J B W.1970.Geology of the country around Bewcastle.Memoir of the Geological Survey of Great Britain, Sheet 12 (England and Wales).
- Fowler, A.1926.The geology of Berwick on Tweed, Norham and Scremerston.Memoir of the Geological Survey of Great Britain, Sheets 1 and 2 (England and Wales).
- George, T N, and Black, W W.1971.The Lower Carboniferous(Dinantian) of England, Wales and Scotland. International Strati-graphical Lexicon, Part 3a Vii. International Union of Geological Sciences.
- Gunn, W.1900.The geology of Belford, Holy Island, and the Farne Islands, Northumberland.Memoir of the Geological Survey of Great Britain, Sheet 4 (England and Wales).
- Gunn, W, and Clough, C T.1895.The geology of part of Northumberland, including the country between Wooler and Coldstream.Memoir of the Geological Survey of Great Britain, Sheet 3 (England and Wales).