Cwm yr Abbey stream section (Ordovician to of the United Kingdom)

Also known as locality 14; top Cwm yr Abbey Mbr./base Afon Ffinnant Fm.

Where: Wales, United Kingdom (51.9° N, 4.2° W: paleocoordinates 68.8° S, 19.9° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Didymograptus varicosus graptolite zone, Carmarthen/Afon Ffinnant Formation, Moridunian to Moridunian (477.7 - 470.7 Ma)

• "Top Cwm yr Abbey Member of the Carmarthen Formation and base of the Afon Ffinnant Formation. Top of Moridunian stage to base of Whitlandian Stage, Arenig Series, varicosus Biozone (see Fortey & Owens 1978; 1987)." (Evans, 2005).

• group of beds-level stratigraphic resolution

Environment/lithology: offshore; black shale and volcaniclastic, argillaceous sandstone

• "A depression, bounded to the northwest by a topographic high [...] has been invoked to produce an environment with restricted circulation in which dysaerobic sediments may have accumulated (Fortey & Rushton 1992)." (Brenchley et al., 2006).

•"The Afon Ffinnant Formation accumulated in moderately deep water into which gravity-flow deposits were fed." (Cope, 2005, Palaeontology 48(2)).

• "The Carmarthen Formation of the Carmarthen area (later Moridunian in age) is developed in a distinctive euxinic facies (Fortey & Owens 1978)" (Bevins et al., 1992 p. 24, Geol. Soc. Mem. 13). The stratigraphic column of the Carmarthen area in fig. 3.23 of Brenchley et al. (2006, in Brenchley & Rawson (eds.), The Geology of England and Wales) gives the lithology of the Cwm yr Abbey Mbr. as "dysaerobic shales" and the lithology of the Afon Ffinnantr Fm. as coarser siliciclastics with intercalations of black shales.

Size class: macrofossils

Preservation: cast

Collection methods: NMW = National Museums and Galleries of Wales

Primary reference: D. H. Evans. 2005. The Lower and Middle Ordovician cephalopod faunas of England and Wales. Monograph of the Palaeontographical Society 623:1-81 [B. Kröger/B. Kröger/B. Kröger]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 89427: authorized by Björn Kröger, entered by Torsten Liebrecht on 19.05.2009

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Cephalopoda
 Orthocerida - Baltoceratidae
Semiannuloceras abbeyense
Semiannuloceras abbeyense Evans 2005
NMW 88.30G.39, 88.30G.40, 88.30G.42 to 88.30G.51 (all are paratypes)