The BGS Lexicon of Named Rock Units — Result Details

Ardnish Formation

Computer Code: ADS Preferred Map Code: AdS
Status Code: Pending Upgrade
Age range: Hettangian Age (JH) — Sinemurian Age (JS)
Lithological Description: Sandstone, siltstone, fissile micaceous mudstone, with thin ironstones in the lower section. Gryphaea common.
Definition of Lower Boundary: Lithology change, grain size decreases. Sporadic ironstones define boundary.
Definition of Upper Boundary: Overlain by fissile mudstones of the Pabay Shale Formation.
Thickness: 55 to 78m
Geographical Limits: Sea of the Hebrides Basin.
Parent Unit: Lias Group (LI)
Previous Name(s): Hallaig Sandstone (-632)
Upper Broadford Beds (-6)
Alternative Name(s): Hallaig Sandstone Member
Pabay Shale Formation
Reference Section  Ardnish Peninsula, Broadford Bay, southern Skye. Hallam, 1959. 
Hallam, A. 1959. Stratigraphy of the Broadford Beds of Skye, Raasay and Applecross. Proceedings of the Yorkshire Geological Society, Vol.32, 165-184. 
Morton, N. 1999. Discussion of the Lower Lias Group of the Hebrides Basin; reply by Hesselbo, S P, Oates, M J and Jenkyns, H C. Scottish Journal of Geology, Vol.35 Part 1, 85-88. 
Morton, N and Hudson, J D, 1995. Field Guide to the Jurassic of the Isles of Raasay and Skye, Inner Hebrides, north-west Scotland. In: Taylor, P D (editor), Field Geology of the British Jurassic. Geological Society of London, 209-280. 
Morton, N. 1999b. Middle Hettangian (Lower Jurassic) ammonites from the Isle of Raasay, Inner Hebrides, and correlation of the Hettangian - lowermost Sinemurian Breakish Formation in the Skye area, north-western Scotland. Scottish Journal of Geology, Vol.35, Part 2, 119-130. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S071 S081