The Clackmannan Group is the name given to a suite of rocks of late Dinantian and Namurian age laid down during the

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

period in the Midland Valley of Scotland.

Description

The Group comprises a lower unit of coarse sandstones,

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

, and limestones with thin coals and ironstones known as the Lower Limestone Formation, an overlying sequence of similar rocks known as the Limestone Coal Formation, then an Upper Limestone Formation and at its top the sandstones of the Passage Formation. This last formation also includes fireclays, siltstones, mudstones, ironstones, coal and seatrocks. The Clackmannan Group conformably overlays the rocks of the

Strathclyde Group The Strathclyde Group is a geological group found in the Midland Valley of Scotland. It preserves fossils of Visean age (early Carboniferous period). See also * List of fossiliferous stratigraphic units in Scotland See also *Lists of fo ...

and underlays the

Coal Measures In lithostratigraphy, the coal measures are the coal-bearing part of the Upper Carboniferous System. In the United Kingdom, the Coal Measures Group consists of the Upper Coal Measures Formation, the Middle Coal Measures Formation and the Lower Coal ...

, this latter boundary also being conformable.

Paleontology

Remains of the prehistoric shark †''

Cladodus elegans ''Cladodus'' is an extinct genus of cartilaginous fishes in the family Cladoselachidae. As the name implies, they are a type of cladodont, primitive sharks with teeth designed to snag fish and swallow The swallows, martins, and saw-wings, or ...

'' Newberry & Worthen, 1870 (braincase and a tooth) have been found in the Lower Limestone Formation.The Braincase and Jaws of Cladodus from the Lower Carboniferous of Scotland. Michal Ginter and John G. Maisey, Palaeontology, March 2007, Volume 50, Issue 2, pages 305–322,

References

{{reflist Geological groups of the United Kingdom Geologic formations of Scotland Fossiliferous stratigraphic units of the United Kingdom Carboniferous System of Europe Carboniferous Scotland Carboniferous southern paleotropical deposits