Computer Code: |
POS |
Preferred Map Code: |
notEntered |
Status Code: |
Full |
Age range: |
Visean Age (CV)
— Visean Age (CV) |
Lithological Description: |
At the top of the Teign Chert, shales containing Posidonia becheri are overlain by interbedded shales, cherts and thin limestones. A band with spirally striate goniatites is present above the beds containing Posidonia. |
Definition of Lower Boundary: |
Boundary with main part of Teign Chert taken at level where well-bedded cherts become predominant. |
Definition of Upper Boundary: |
Conformably succeeded by the Ashton Shale (basal member of the Crackington Formation). The boundary is reflected in the topography, with the Teign Chert (including the Posidonia Beds) forming prominent features. |
Thickness: |
30-45 metres. |
Geographical Limits: |
Middle Teign Valley, Devon. |
Parent Unit: |
Teign Chert Formation (TCH)
|
Previous Name(s): |
Spara Bridge Formation [Obsolete Name and Code: Use POS, TCH]
(-1764)
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Section |
Road section west of Lower Ashton, Devon. Detailed section (in cherts with subordinate siliceous shales, with tuffs and scarce limestone). Given in Selwood et al., 1984, p. 69. |
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). |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E339
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