| Computer Code: |
RSL |
Preferred Map Code: |
notEntered |
| Status Code: |
Full, without ratification |
| Age range: |
Famennian Age (DA)
— Tournaisian Age (CT) |
| Lithological Description: |
[Obsolete: use RRAM] Purple slightly micaceous slates with crinoid debris and other fossil fragments (including bivalves, clymenids and rare trilobites and ostracods), green slates and black siliceous slates. A prominent horizon of calcareous laminated siltstone is present at the top of the unit. |
| Definition of Lower Boundary: |
Not defined. |
| Definition of Upper Boundary: |
The Rora Slate is only known within the Liverton Unit (i.e. the thickness of rock that is bounded by the Bickington Thrust to the south, and the Silverbrook Thrust to the north). Conformable with the overlying Lower Culm cherts on the northern slopes of Ramshorn Down [SX 7924 7378]; elsewhere it is mostly faulted against the Culm Measures. Across the conformable contact, a transition would be seen from the slightly micaceous slates of varying colours of the Rora Slate (described in the lithology section) to the bedded siliceous rocks and slates with local interbedded pyroclastic rocks of the Mount Ararat Chert. |
| Thickness: |
Not defined. |
| Geographical Limits: |
Rora Slate is confined to the Livington Unit (the thickness of rock that is bounded by the Bickington Thrust to the south, and the Silverbrook Thrust to the north). The outcrop of the Rora Slate is confined to the area around, and to the north-west of, Bickington in south Devon. |
| Parent Unit: |
none recorded or not applicable
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
South Rora Down Quarry, Devon. Selwood et al., 1984. |
| Reference(s): |
| Selwood, E B, Edwards, R A, Simpson, S, Chesher, J A, Hamblin, R J O, Henson, M R, Riddolls, B W and Waters, R A. 1984. Geology of the countryside around Newton Abbot. Memoir of the British Geological Survey, Sheet 339 (England and Wales). |
| Ussher, W A E. 1913. Geology of the country around Newton Abbot. Memoir of the British Geological Survey, Sheet 339. (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E339
|
