Cwm yr Abbey stream section (top of Cwm yr Abbey Mbr.) (Ordovician of the United Kingdom)

Also known as locality 14; type horizon of Semiannuloceras abbeyense Evans

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

• coordinate stated in text

• hand sample-level geographic resolution

When: Didymograptus varicosus graptolite zone, Cwm yr Abbey Member (Carmarthen Formation), Moridunian (477.7 - 473.8 Ma)

• " [...] horizon high in the Cwm yr Abbey Member of the Carmarthen Formation." (Evans, 2005)

• bed-level stratigraphic resolution

Environment/lithology: offshore; black shale

• "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 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".

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 89426: authorized by Björn Kröger, entered by Torsten Liebrecht on 19.05.2009

Creative Commons license: CC BY (attribution)

Taxonomic list

• Only the holotype specimen of Semiannuloceras abbeyense is explicitly said to come from this particular horizon. Other specimens listed with regard to the Cwm yr Abbey locality (see PBDB coll. no 89427) possibly also come from this bed but no particular horizon is given for any of these specimens in the primary reference.
Show authors, comments, and common names
Cephalopoda
 Orthocerida - Baltoceratidae
Semiannuloceras abbeyense n. gen. n. sp.
Semiannuloceras abbeyense n. gen. n. sp. Evans 2005
NMW 88.30G.41 (type)