The BGS Lexicon of Named Rock Units — Result Details
Ynyslas Formation
| Computer Code: | YNYSS | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Holocene Epoch (QH) — Holocene Epoch (QH) | ||
| Lithological Description: | Stratified, unconsolidated, fine- to medium-grained, quartz sand with shell debris. | ||
| Definition of Lower Boundary: | Commonly unconformable on Flandrian or Late Devensian superficial deposits. In the type area it overlies Flandrian storm beach gravels in the west and peat in the east; locally, it overlies bedrock (Godwin, 1943). | ||
| Definition of Upper Boundary: | Generally the ground surface, but locally, contact with overlying Flandrian deposits. In the type area the formation is locally overlain by Tidal Flat Deposits (British Coastal Deposits Group). | ||
| Thickness: | Exceptionally to 10.5m in the type area, but generally less and in accordance with the topographic expression of dune forms (Cave and Hains, 1986). | ||
| Geographical Limits: | Cardigan Bay; principally at Morfa Bychan, Morfa Harlech, Morfa Dyffryn, Poppit Sands, Whitesands Bay and Freshwater West. | ||
| Parent Unit: | British Coastal Deposits Group (COAS) | ||
| Previous Name(s): | Kenfig Formation
(KNFIG)
Kenfig Formation (KNFIG) Blown sand (BSA) |
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| Alternative Name(s): | Kenfig Formation |
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| Stratotypes: | |||
| Type Area | Mostly active dune complex consisting of a narrow strip behind the storm beach from Borth to Aberlerry Farm [SN 609 910], widening northwards to about 1km north of Foel-ynys [SN 607 929] and terminating at Twyni Bach. Relict, older sandhills occur at [SN 612 899]. Cave and Hains, 1986. The deposits developed in response to exposed beach deposits being blown inland by prevailing winds. | ||
| Reference(s): | |||
| Godwin, H. 1943. Coastal peat beds of the British Isles and North Sea. Journal of Ecology, Vol.31, 199-247. | |||
| Cave, R and Hains, B A. 1986. Geology of the country between Aberystwyth and Machynlleth. Memoir of the British Geological Survey, Sheet 163 [England and Wales]. [London: HMSO.]. 148pp. | |||
| Bowen, D Q. 1999. Wales. Chapter 7 in A revised correlation of Quaternary deposits in the British Isles. Bowen, D Q (editor). Geological Society of London Special Report, No. 23. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E244 E209 E193 E163 E149 E135 E119 E134 | |||