| Computer Code: |
RWV |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Arenig Series (OR)
— Abereiddian Stage (O2) |
| Lithological Description: |
Rhyolitic lavas and tuffs, spilitic and basic lavas, and manganese ash occuring within the hirundo and bifidus zones. |
| Definition of Lower Boundary: |
Drawn at the base of the metasomatised tuff/manganese ore where it rests upon possibly dolerite, but the underlying rocks are not seen. |
| Definition of Upper Boundary: |
Drawn at the conformable upward passage of the Rhiw Volcanic Group into the overlying Tal-y-fan argillites. |
| Thickness: |
Not known. |
| Geographical Limits: |
Around Rhiw, near Porth Neigwl, Lleyn Peninsula, Caernarvonshire. |
| Parent Unit: |
Not Applicable (-)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Around Rhiw, near Porth Neigwl, Caernarvonshire. |
| Reference(s): |
| Matley, C A, 1932. The geology of the country around Mynydd Rhiw and Sarn, south-western Lleyn, Carnarvonshire. Quarterly Journal of the Geological Society, Vol.88, p.272. |
| Matley, C A, 1938. The geology of the country around Pwllheli, Llanbedrog and Madryn, southwest Carnarvonshire. Quarterly Journal of the Geological Society of London, Vol.94, 555-606. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
