The BGS Lexicon of Named Rock Units — Result Details
Cilan Formation
| Computer Code: | CIG | Preferred Map Code: | CiG |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | St David's Series (ED) — St David's Series (ED) | ||
| Lithological Description: | Coarse-grained, thickly-bedded turbiditic sandstones. | ||
| Definition of Lower Boundary: | Conformably overlies manganiferous siltstones belonging to the Trwyn-y-Fulfran Formation. Boundary taken at the first coarse-grained sandstone of the Cilan Formation. | ||
| Definition of Upper Boundary: | Overlain conformably by red, brown and green siltstones and subordinate sandstones of the Ceiriad Formation. | ||
| Thickness: | 400m | ||
| Geographical Limits: | St Tudwal's Peninsula, northwest Wales. | ||
| Parent Unit: | Harlech Grits Group (HGG) | ||
| Previous Name(s): | Cilan Grits (In Part) [Obsolete Name and Code: Use CIG]
(-4540)
Cilan Grits (-784) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Partial Type Section | Trwyn Llech-y-doll. Top of Formation. Young et al., 1994. | ||
| Type Section | Mostly inaccessible cliffs at Trwyn Cilan, St Tudwal's Peninsula. | ||
| Reference(s): | |||
| Young, T P, Martin, F, Dean, W T and Rushton, A W A. 1994. Cambrian stratigraphy of St Tudwal's Peninsula, Gwynedd, northwest Wales. Geological Magazine, Vol.131, 335-360. | |||
| Young, T P, Gibbons, W and McCarroll, D. 2002. Geology of the country around Pwllheli. Memoir of the British Geological Survey, Sheet 134 (England and Wales). | |||
| Nicholas, T C. 1915. Geology of the St Tudwal's Peninsula. Quarterly Journal of the Gelogical Society of London, Vol.71, 83-143. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E134 | |||