At least 45 ofthe approximately 600 species of molluscs documented from the Bowden shell bed exhibit evidence of bioerosion in the form of completely or incompletely penetrative (failed) small round holes. Assessment of previously illustrated material, together with new collections made by us, shows that these borings are assignable to the ichnotaxon Oichnus Bromley, 1981, in particular O. paraboloides Bromley, 1981 and O. simplex Bromley, 1981. Observations suggest that the borings were not a result ofparasitism nor simple random excavations by bioerodingorganisms. Rather, they are interpreted as a result of opportunistic predatory activities ofcannibalisticgastropods, O. paraboloides probably havingbeen produced by naticids and O. simplex by muricids.