The BGS Lexicon of Named Rock Units — Result Details

Grain Heads Siltstone Member

Computer Code: GHD Preferred Map Code: GHD
Status Code: Full
Age range: Telychian Age (ST) — Telychian Age (ST)
Lithological Description: Highly fossiliferous silty mudstones, siltstones and fine-grained sandstones.
Definition of Lower Boundary: Conformable: green-grey bioturbated mudstones immediately overlying medium- to coarse-grained sandstones of the Cock Rig Formation.
Definition of Upper Boundary: Conformable: highest laminated sandy siltstones and fine-grained sandstones with abundant bioclasts on bedding planes, below Lamb Rig Siltstone Member.
Thickness: 30-55m
Geographical Limits: Pentland Hills, Midland Valley.
Parent Unit: Wether Law Linn Formation (WLN)
Previous Name(s): Lower Part Of Bed C (-281)
Lower Part Of Fossiliferous Mudstones And Siltstones (-3432)
Units A To C, Wether Law Linn Formation (-3433)
Beds At D To E (-929)
Beds D To E (-1559)
Lower Member, Wether Law Linn Formation (-2203)
Alternative Name(s): none recorded or not applicable
Type Section  Wether Law Linn, 140m to 290m upstream from confluence with North Esk river. 
Reference Section  Deerhope Burn, North Bank, 600m ESE from Wether Law Summit 
Partial Type Section  Top of Grain Heads Siltstone Member and base of Lambrig Siltstone Member, North Esk river. 
Peach, B N and Horne, J. 1899. The Silurian Rocks of Britain, Volume 1. Scotland. Memoir of the Geological Survey of the United Kingdom. 
Robertson, G, 1986. North Esk Inlier. 174-185 in Lothian Geology. An Excursion Guide. McAdam, A D and Clarkson, E N K (editors). [Edinburgh: Scottish Academic Press.] 
Henderson, J and Brown, D J, 1870. On the Silurian rocks of the Pentland Hills. Transactions of the Edinburgh Geological Society, Vol.1, 266-272. 
Howell, H H and Geikie, A, 1861. The Geology of the neighbourhood of Edinburgh (1st edition). Memoir of the Geological Survey, Scotland. 
Robertson, G, 1989. A palaeoenvironmental interpretation of the Silurian rocks in the Pentland Hills, near Edinburgh, Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences, Vol.80, 127-141. 
Lamont, A, 1952. Ecology and correlation of the Pentlandian - a new division of the Silurian System in Scotland. 27-32 in Faunal and floral facies and zonal correlation. Dighton-Thomas, H (editor). Report of the 18th Session of the International Geological Congress, Great Britain, 1948, Pt.10. 
Tipper, J C, 1976. The stratigraphy of the North Esk Inlier. Scottish Journal of Geology, Vol.12, Pt, 15-22. 
Mitchell, G H. 1962. The geology of the neighbourhood of Edinburgh. (Explanation of Sheet 32) Third Edition. (Reprinted 1980). Memoir of the Geological Survey of Great Britain (Scotland). 
1:50K maps on which the lithostratigraphical unit is found, and map code used: