| Computer Code: |
RDD |
Preferred Map Code: |
Rdd |
| Status Code: |
Full |
| Age range: |
Telychian Age (ST)
— Telychian Age (ST) |
| Lithological Description: |
Thinly interbedded turbidite sandstones and mudstones with abundant thicker beds of argillaceous coarse sandstone. |
| Definition of Lower Boundary: |
Base of lowest thick argillaceous sandstone bed overlying Caeran Mudstones. |
| Definition of Upper Boundary: |
Top of highest thick argillaceous sandstone bed below lower tongue of Glenyrafon Formation. |
| Thickness: |
c.1000m |
| Geographical Limits: |
Central Wales. |
| Parent Unit: |
Cwmystwyth Grits Group (CWY)
|
| Previous Name(s): |
Rhuddnant Grits (Formation), Cletwr Facies [Obsolete Name And Code: Use RDD]
(CLFA)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Nant Rhuddnant between upper reaches of Rhuddnant Gorge and Rhuddnant Tarn. |
| Reference(s): |
| Jones, O T. 1909. The Hartfell-Valentian succession in the district around Plynlimon and Pont Erwyd (north Cardiganshire). Quarterly Journal of the Geological Society of London, Vol.65, 463-536. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E179
|
