Inverclyde Group

Name

Previous names: Cementstone Group (A); Cementstone Group (B); Cementstone Group(CMST); Stirling Group (SLG)

Lithology

Sandstones containing pedogenic limestone and dolomite nodules ('cornstones'), fine-grained carbonate as beds, nodules and pebbles, and grey and brown mudstones containing thin beds of limestone and dolomite ('cementstones'); subordinate siltstone and mudstone.

Lower and upper boundaries

Lower Boundary: At base of Kinnesswood Formation - at incoming of common pedogenic carbonate above a red-bed sequence, the Stratheden Group. Normally conformable, locally unconformable in west.

Upper Boundary: At top of Clyde Sandstone Formation (in west) or of Tyninghame Formation (Lothian) or of Balcomie eds (Fife); at incoming of coal, blackshale, seatearth or volcanic rocks of the Strathclyde Group; conformable or unconformable.

Thickness

To c. 1500m. the Inverclyde Group is up to 900 m thick in the Tweed Valley, Northumberland, and up to 640 m thick in the Solway Firth area.

Geographical limits

Midland Valley of Scotland.

Type area

Greenock, Inverclyde, Scotland. (Ref Sections: See Type Sections of component units: Kinnesswood, Ballagan, Clyde Sandstone and Tyminghame formations and Balcomie Beds).

Age range

Courceyan Age (CF) — Chadian Age (CI)

References

Forsyth, I H and Chisholm, J I, 1977. The geology of east Fife. Memoirs of the Geological Survey of Great Britain. Paterson, I B and Hall, I H S, 1986. Lithostratigraphy of the late Devonian and early Carboniferous rocks in the Midland Valley of Scotland. British Geological Survey Report, 18/3. Francis, E H, Forsyth, I H, Read, W A and Armstrong, M. 1970. The geology of the Stirling district. Memoir of the Geological Survey of Great Britain, Sheet 39 (Scotland). Chisholm, J I, MacAdam, A D, Brand, P J. 1989. Lithostratigraphical classification of Upper Devonian and Lower Carboniferous rocks in the Lothians. British Geological Survey Technical Report, WA/89/26. MacGregor, A G, 1960. Division of the Carboniferous on Geological Survey Scottish Maps. Bulletin of the Geological Survey of Great Britain, No.16, 127-130. Chisholm, J I and Dean, J M, 1974. The Upper Old Red Sandstone of Fife and Kinross: A fluviatile sequence with evidence of marine incursion. Scottish Journal of Geology, Vol. 10, 1-30. Browne, M A E, 1980. The Upper Devonian and Lower Carboniferous (Dinantian) of the Firth of Tay, Scotland. Report of the Institute of Geological Sciences, No. 80/9.