Cwm Graig Ddu Quarry (Silurian of the United Kingdom)

Where: Wales, United Kingdom (52.0° N, 3.0° W: paleocoordinates 27.9° S, 13.0° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Monograptus tumescens [= incipiens] zone, Pterinea Beds Member (Wilsonia Shales Formation), Gorstian (427.4 - 425.6 Ma)

• Lower half of the Pterinea Beds just a few metres above the junction with the underlying 'Shales with thin slumps' division.

• group of beds-level stratigraphic resolution

Environment/lithology: basinal (); siltstone and gray siltstone

• Beds represent deposits formed on the palaeoslope of the eastern mafgin of the Welsh basin. Pnecontemporaneous slumps suggest that the plants may have been derived from the southeast, i.e. from the direction of the shelf and land.
• Buff-grey, slightly micaceous flaggy siltstones. Darker grey siltstones in slightly younger beds in the centre of the quarry contain numerous fragments.

Size class: macrofossils

Preservation: adpression, coalified, original carbon

Collection methods: chemical, mechanical, peel or thin section,

• Plants first noted by Straw (1953) and later by Baker & Hughes, 1979. This is the most comprehensive account.

Primary reference: D. Edwards, M. G. Bassett, and C. W. Rogerson. 1979. The earliest vascular land plants: continuing the search for proof. Lethaia 12:313-324 [P. Gensel/M. Kotyk]more details

Purpose of describing collection: taphonomic analysis

PaleoDB collection 10661: authorized by Pat Gensel, entered by Michele Kotyk on 08.06.2001

Creative Commons license: CC BY (attribution)

Taxonomic list

Psilophytopsida
 Psilophytales -
Hostinella
  -
Hostinella sp. Barrande 1882
Cephalopoda
  -
Cephalopoda indet. Cuvier 1797
orthoconic nautiloids
Bivalvia
 Ostreida - Pterineidae
Pterinea tenuistriata n. sp. oyster
(this is the type locality)
  -
"Pelecypoda indet." = Bivalvia
"Pelecypoda indet." = Bivalvia Linnaeus 1758 clam
bivalves
Brachiopoda
  -
Brachiopoda indet. Cuvier 1805
rhynchonellid
Bryozoa
  -
Bryozoa indet. Ehrenberg 1831
Pterobranchia
 Graptoloidea - Monograptidae
Saetograptus leintwardinensis graptolite
ssp. incipiens
Graptolitidae
  - Graptolitidae
"Graptolites" indet. McCoy 1874
rare forms