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): Upper Broadford Beds (-6)
Hallaig Sandstone (-632)
Alternative Name(s): Hallaig Sandstone Member
Pabay Shale Formation
Stratotypes:
Reference Section  Ardnish Peninsula, Broadford Bay, southern Skye. Hallam, 1959. 
Reference(s):
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. 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. 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. 
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. 
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. 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,p119-130. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S071 S081