Computer Code: |
RDD |
Preferred Map Code: |
Rdd |
Status Code: |
Pending Upgrade |
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
|