ABSTRACT: Fosillized solid specimens can be identified as Coptocampylodon lineolatus Elliott 1963 in Middle Eocene clastic deep-sea sediments of Istria. Despite their homogenous composition and cylindrical shape with longitudinal ribs radiating from rounded poles, which are features commonly observed in coprolites, they have commonly been considered as "incertae sedis". Chemical analysis reveals close similarity between the fossilized specimen and the host marl. These characteristics clearly indicate that the fossilized specimens are coprolites of a deposit feeding, and most probably an invertebrate organism.