Two characteristic and common trace fossils, lightly etched into the surfaces of skeletal substrates in marine environments, are named Centrichnus eccentricus igen. et isp. nov., and C. concentricus isp. nov. respectively. The first is new, not having been described in recent or fossil material before. It corresponds to the attachment scars produced by anomiid bivalves where they anchor their unique calcified byssus to the substrate. C. concentricus, on the other hand, is well known but hitherto has not been named. It corresponds to the etching scars produced beneath verrucid cirripedes on calcareous substrates.