| Computer Code: |
GYM |
Preferred Map Code: |
GYM |
| Status Code: |
Full |
| Age range: |
Sheinwoodian Age (SS)
— Homerian Age (SH) |
| Lithological Description: |
Mainly mudstone, silty medium-dark grey homogeneous, slumped and in part thinly interbedded with thin fine-grained sandstones. |
| Definition of Lower Boundary: |
Diachronous, upon the greywacke sandstones of the Denbigh Grits/Penstrowed Grits. |
| Definition of Upper Boundary: |
Where the bedding becomes prominent in rhythmic ribbon banded mudstones and siltstones of the Nantglyn Flags type. In practice, at the base of the Mottled Mudstone Member. |
| Thickness: |
At least 130m. |
| Geographical Limits: |
So far 1:50 000 map, Sheet 165 (Montgomery), western edge. |
| Parent Unit: |
Nantglyn Flags Formation (NGF)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
To be designated - a better section probably exists on adjacent, but unsurveyed ground. |
| Reference Section |
Henglog Dingle. |
| Reference(s): |
| none recorded or not applicable |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E165
|
