Eelwell limestone Member
Eelwell limestone Member is part of the Alston Formation
Limestone, grey, bioclastic, generally devoid of mudstone partings; typically rich in algal remains with a prominent fauna of brachiopods and corals; appreciably dolomitised in part, giving a brown-weathered and vuggy appearance.
The type areas are near Walwick, about 2.km west of Chollerford, Northumberland (NY 8878 7033 to 9083 7116) where Frost and Holliday (1980, p. 36) referred to the typically massive, grey, bioclastic limestone, devoid of mudstone partings, being well exposed; and Cargie’s Plantation (NU 024 495) to Saltpan Rocks (NU 025 490), Seahouses, approximately 3 km south-east of Berwick-upon-Tweed, Northumberland where Fowler (1926, p. 25) described the limestone exposed on the shore as browned (as if dolomitised), steeply dipping, contorted and fossiliferous.
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; typically sandstone.
The upper boundary of the member is taken at the top of the uppermost limestone bed that is overlain by a sequence of dark grey mudstones and siltstones, containing ironstone nodules locally.
Between 5 and 10 m.
Distribution and regional correlation
A widespread limestone member within the Alston Formation, occurring throughout the Northumberland Trough in northern England and the Scottish Borders, stratigraphically lying below the Three Yard Limestone and above the Oxford Limestone (Figure 11, Column 3; Figure 12, Columns 1–4). This definition incorporates its correlated unit in the Langholm and Bewcastle areas of the Scottish Borders region, the Harelawhill Limestone.
- 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).
- Chadwick, R A, Holliday, D W, Holloway, S, and Hulbert, A G.1995.The structure and evolution of the Northumberland–Solway Basin and adjacent areas.Subsurface Memoir of the British Geological Survey. (Keyworth, Nottingham: British Geological Survey.)
- Day, J B W.1970.Geology of the country around Bewcastle.Memoir of the Geological Survey of Great Britain, Sheet 12 (England and Wales).
- 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).
- Lumsden, G I, and Wilson, R B.1961.The stratigraphy of the Archerbeck Borehole, Canonbie, Dumfriesshire.Bulletin of the Geological Survey of Great Britain, No. 18, 1–89.