Ffynnon-y-mab (Ordovician of the United Kingdom)

Where: Wales, United Kingdom (53.3° N, 4.3° W: paleocoordinates 65.0° S, 18.3° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Treiorwerth Formation, Arenig (478.6 - 466.0 Ma)

• "upper Arenig... uppermost metre of the 5 m exposed... shell beds as much as 10 cm thick"

• group of beds-level stratigraphic resolution

Environment/lithology: open shallow subtidal; sandstone and fine-grained conglomerate

• "shallow water surrounding an island or group of islands... near-shore lag concentrations"
• "near the base of the formation, in well-bedded sandstone and fine-grained conglomerate... Most of the [rock] samples... were weathered, decalcified and rusty brown"

Size class: macrofossils

Preservation: cast, mold/impression

Collection methods: bulk, hydrochloric,

• new collection from 1971

•part of the sample, from less weathered sediment, was "decalcified in hydrochloric acid"

Primary reference: R. B. Neuman and D. E. B. Bates. 1978. Reassessment of Arenig and Llanvirn age (early Ordovician) brachiopods from Anglesey, north-west Wales. Palaeontology 21(3):571-613 [J. Alroy/J. Alroy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 69096: authorized by John Alroy, entered by John Alroy on 18.02.2007

Creative Commons license: CC BY (attribution)

Taxonomic list

Trilobita indet. Walch 1771 trilobite
 Agnostida - Metagnostidae
cf. Geragnostus sp. Howell 1935 trilobite
"probably Geragnostus"
 Billingsellida - Polytoechiidae
 Strophomenida - Taffiidae
"Reinversella monensis" = Inversella (Reinversella)
"Reinversella monensis" = Inversella (Reinversella)
 Kutorginida -
Kutorginida indet. Kühn 1949
 Pentamerida - Porambonitidae
Porambonitidae indet. Ulrich and Cooper 1936
 Pentamerida - Huenellidae
 Pentamerida - Tetralobulidae
Rugostrophia sp. Neuman 1971
 Pentamerida - Clarkellidae
 Protorthida - Skenidiidae
Skenidioides sp. Schuchert and Cooper 1931
 Orthida - Paurorthidae
? Paurorthis sp. Schuchert and Cooper 1931
 Orthida - Hesperonomiidae
Treioria chaulioda n. gen. n. sp. Neuman and Bates 1978
 Orthida - Orthidae
Orthambonites sp. Pander 1830
 Orthida - Productorthidae
Productorthis sp. Kozlowski 1927
 Orthida - Cyclocoeliidae
 Orthida - Platystrophiidae
 Craniida - Craniidae
Craniidae indet. Menke 1828
? Petrocrania sp. Raymond 1910
 Trepostomata -
Trepostomata indet. Ulrich 1882
"bryozoans... generalized trepostomes... [plus] branches resembling those of phylloporinids"
Pelmatozoa indet. Leuckart 1848
"pelmatozoan ossicles"