| Computer Code: |
DGD |
Preferred Map Code: |
DGd |
| Status Code: |
Full |
| Age range: |
Sheinwoodian Age (SS)
— Sheinwoodian Age (SS) |
| Lithological Description: |
Alternating pale grey, bioturbated siltstone and laminated hemipelagite. |
| Definition of Lower Boundary: |
A transition over a few hundred millimetres from massive, hard, poorly fissile grey siltstone of the Browgill Formation, into pale blueish or greenish grey muddy siltstone with a slightly better cleavage. |
| Definition of Upper Boundary: |
Taken at the top of the highest, pale grey, massive or bioturbated mudstone bed that is succeeded by more than 200mm of laminated hemipelagite. |
| Thickness: |
From 10m to 30m thick. |
| Geographical Limits: |
A narrow unit, extending across the south eastern Lake District, mapped as a distinct unit to about 4km southwest of Coniston village. It is present farther to the southwest, but has not been mapped due to poor exposure. It is shown on the Coniston 25k map but not the 50k Ambleside or Kendal sheets. It is also recognised in the Howgill Fells, and crops out on Sheets E38 and E39, but is only shown on the former. |
| Parent Unit: |
Brathay Formation (BRF)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
The hillside immediately west of Dixon Ground, which is about 200m west of the centre of Coniston village. Kneller, 1990. |
| Type Section |
Immediately east of the track leading north from Knipe Fold. Kneller, 1990. |
| Reference(s): |
| Kneller, B C. 1990. The Wenlock rocks of sheet 38 (Ambleside). British Geological Survey Technical Report, WA/90/64 |
| Kneller, B C, Scott R W, Soper N J, Johnson E W and Allen P M, 1994. Lithostratigraphy of the Windermere Supergroup, Northern England. Geological Journal, Vol. 29, 219-240. |
| Moseley F. 1984. Lower Palaeozoic lithostratigraphical classification in the English Lake District. Geological Journal, Vol. 19, p. 239-247. |
| Marr J E. 1892. On the Wenlock and Ludlow strata of the Lake District. Geological Magazine, Vol. 9, p 534-541. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E038
E039
|
