Bryozoans in the British Jurassic

Dr Paul D Taylor (UK) Fossil collectors often overlook, or worse discard, bryozoans. There are several reasons: some bryozoans are small and not easily spotted in the field, others are mistaken for non-descript sponges or algae, while bryozoans cemented to the surfaces of other fossils can be cursed for detracting from the value of the main fossil. But bryozoans are fascinating fossils in their own right and ought not to be ignored. Bryozoans are a morphologically varied phylum of colonial invertebrates. The myriad of colony-forms they exhibit reflect adaptations that evolved to allow them to prosper as immobile colonial animals living on the seabed and feeding on passing plankton (Taylor, 2020). The majority of the more than 6,000 bryozoan species living today possess resistant skeletons of calcium carbonate, and the calcareous skeletons of fossil bryozoans are abundant globally in rocks ranging back to the Early Ordovician, some 480 million years. Fossil bryozoans in Britain occur in marine sedimentary rocks from every post-Cambrian geological period except the Triassic. Ordovician bryozoans can be found in the Welsh Borderlands and in southern Scotland, Silurian bryozoans in the West Midlands and Shropshire, Devonian bryozoans in Devon, Carboniferous bryozoans in the Pennines and other places where the Carboniferous Limestone outcrops, and Permian bryozoans in the Magnesian Limestone of northeast England. Previous contributions to Deposits have described bryozoans from the Chalk of Late Cretaceous age (Taylor, 2018) and the Pliocene Coralline Crag of Suffolk (Taylor and Milne, 2009). Here, I focus on British Jurassic bryozoans. Jurassic … Read More