Where: Wales, United Kingdom (51.4° N, 3.2° W: paleocoordinates 37.5° N, 0.8° E)

• coordinate stated in text

• small collection-level geographic resolution

When: Psiloceras tilmanni ammonoid zone, White Lias Formation (Penarth Group), Early/Lower Hettangian (201.3 - 196.5 Ma)

• Fallen material at the base of a cliff section that exposes rocks of the Penarth Group. The location of the pyritized ammonite at the base of the cliff, along with its fragile nature, indicates that it could not have moved far from its original location, but it was not found in situ. Attempts were made using geochemical methods to try and determine the bed from which the specimen originated. Rock samples collected from each of the beds in the cliff section above where the pyritized ammonite was found were analysed by X-ray diffraction (XRD), as was the limestone adhering to the pyritized ammonite. The results of these XRD analyses suggest a match between the limestone at the centre of the ammonite whorl and the limestone of bed WL1. Significantly, this bed is also the only one in the cliff section to contain pyrite.

Environment/lithology: lithified limestone

Size class: macrofossils

Preservation: replaced with pyrite

Collection methods: Repository: National Museum of Wales

Primary reference: P. Hodges. 2021. A new ammonite from the Penarth Group, South Wales and the base of the Jurassic System in SW Britain. Geological Magazine 158:1109-1114 [M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 220336: authorized by Matthew Clapham, entered by Matthew Clapham on 22.05.2021

Creative Commons license: CC BY (attribution)