The BGS Lexicon of Named Rock Units — Result Details

Portree Shale Formation

Computer Code: PEE Preferred Map Code: Pee
Status Code: Pending Upgrade
Age range: Toarcian Age (JT) — Toarcian Age (JT)
Lithological Description: Dark grey/black mudstones of anoxic deposition dominate the succession, which is locally laminated, organic-rich and contains few benthic fossils. Poorly exposed.
Definition of Lower Boundary: Abrupt lithological change from sandstone of the Scalpay Sandstone Formation to anoxic mudstone.
Definition of Upper Boundary: Gradational transition to limestone of the Raasay Ironstone Formation.
Thickness: 2m+
Geographical Limits: Sea of the Hebrides Basin.
Parent Unit: Lias Group (LI)
Previous Name(s): Portree Shale (-2970)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  South of Dun Liath ruins, near Elgol, Strathaird, Skye. Morton, N and Hudson, J D, 1995. 
Reference Section  Coastline east of the Trotternish Ridge, Skye. Morton, N and Hudson, J D, 1995. 
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. 1965. The Bearrenaig Sandstone Series (Middle Jurassic) of Skye and Raasay. Scottish Journal of Geology, Vol.1, 189-216. 
Fyfe, J A, Long, D and Evans, D, 1993. United Kingdom offshore regional report: the geology of the Malin - Hebrides sea area (London: HMSO for the British Geological Survey). 
Hesselbo, S P, Oates, M J and Jenkyns, H C. 19998. The Lower Lias Group of the Bebrides Basin. Scottish Journal of Geology, Vol.34, Part 1, 23-60. 
Cox, B M, Page, K N and Morton, N, 2002. The Middle Jurassic stratigraphy of Scotland. In Cox, B M and Sumbler, M G (editors), British Middle Jurassic Stratigraphy. Geological Conservation Review Series, Vol.26. (Peterborough: Joint Nature Conservation Committee/Chapman and Hall.) 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S071 S080 S081 S051 S052