| Computer Code: |
LONFN |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Bathonian Age (JN)
— Bathonian Age (JN) |
| Lithological Description: |
Comprises dark grey-brown finely laminated fissile mudstone ('paper shale') with interbedded ooidal limestone. Brackish water faunas, including bivalves, conchostracans, gastropods and ostracods are present. Desiccation cracks, indicating emergence, are present in the uppermost beds. |
| Definition of Lower Boundary: |
Underlain by the Kildonnan Member (KILDN). |
| Definition of Upper Boundary: |
As for parent formation. |
| Thickness: |
none recorded or not applicable
|
| Geographical Limits: |
Trotternish district, Skye, north-west Scotland. |
| Parent Unit: |
Lealt Shale Formation (LASH)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Composite succession [NG 517 638 to NG 521 627], 30 m thick, north of Port Earlish, Trotternish (Cox and Sumbler, 2002; Harris and Hudson, 1980, fig. 6). |
| Reference Section |
Outcrops at the Lealt River and cliffs north of the Lealt River mouth, Trotternish [NG 515 604]. The Lonfearn Member is especially well developed here. The different exposures in this area can be readily correlated using marker beds, and a composite section has been made by Hudson and Harris (1979, figs. 2 to 4). |
| Reference(s): |
| Barron, A J M, Lott, G K, and Riding, J B. 2012. Stratigraphical framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf. British Geological Survey Research Report RR/11/06. |
| Cox, B M, and Sumbler, M G. 2002. British Middle Jurassic Stratigraphy. Geological Conservation Review Series No. 26. (Peterborough: Joint Nature Conservation Committee.) |
| Harris, J P and Hudson, J D. 1980. Lithostratigraphy of the Great Estuarine Group (Middle Jurassic), Inner Hebrides. Scottish Journal of Geology, Vol.16(2/3), 231-250. |
| Hudson, J D and Harris, J P. 1979. Sedimentology of the Great Estuarine Group (Middle Jurassic) of north-west Scotland. Symposium sur la Sedimentation de Jurassique Ouest Europeen, Paris, 9-10 May 1977, Association des Sedimentologists Francais, Publication Speciale, No.1, 1-13. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S060
|
