On the trace-fossi Chondrites

The problematical fossil Chondrites, well known from the Flysch of the Alps, Carpathians and Apennines, and from the Lias of Germany, is shown to be common in various Palaeozoic formations of the British Isles and also in the English Lias. The varying forms taken by the fossil are described and explained and shown to be primarily the result of different modes of preservation and not of taxonomic significance. A consideration of the different modes of preservation, as well as of the morphology of the fossil, permits its interpretation as a trace-fossil resulting from the driving of a system of branching tunnels in the sea-bed sediment. A new reconstruction of the fossil has been made. It is tentatively explained as the product of a sipunculoid worm feeding on sediment by means of its extensible proboscis. Various implications of the mode of occurrence of the fossil in particular circumstances are considered.