| Computer Code: |
CIF |
Preferred Map Code: |
notEntered |
| Status Code: |
Pending Upgrade |
| Age range: |
Llandovery Epoch (SL)
— Llandovery Epoch (SL) |
| Lithological Description: |
Comprises banded mudstones and siltstones. Very minor sandstones. Banding is characteristically wide - 10-30cm +, is common. May reach 60cm. Turbiditic mudstones overlain by oxic or anoxic hemipelagite intervals. Graptolitic units may be present. |
| Definition of Lower Boundary: |
Taken to be at the base of a laterally traceable anoxic mudstone (graptolitic) horizon (7878 0050). |
| Definition of Upper Boundary: |
Not seen on Sheet 149. |
| Thickness: |
At least about 800m thick, top of formation not yet located. |
| Geographical Limits: |
Confined to southeast corner of Sheet 149, only present on Sheet SH70SE. Best exposed in base of River Crew. |
| Parent Unit: |
Not Entered (?)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| none recorded or not applicable |
| Reference(s): |
| Scott, M M. 1990. Geological notes and local details for 1:10,000 Sheet SH70SE Llanwrin, part of 1:50,000 Sheet 149 Cadair Idris. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E149
|
