Article: Xiphosurid trace fossils from the Westbury Formation (Rhaetian) of southwest Britain

The abundant and diverse trace fossils attributed to xiphosurid activity on sandstone soles at Westbury on Severn are described and interpreted. The xiphosurids seem to have been active in this area mainly after major storm event sedimentation. Two patterns of scratches, three types of lunate marks, and a bilobate furrow assignable to Cruziana perucca are distinguished. The lunate marks and one pattern of the scratch marks are assigned to Selenichnites isp. The marks were produced either during carnivorous feeding or burrowing for concealment. Variation in the traces is attributed to variable formation and preservation, sediment grain size, mud cohesiveness, as well as sediment thickness above the trace-taking sole surface, which modified the behavioural activity of the trace maker.