Systematic Review of the Genus Skolithos

The trace fossil genus Skolithos Haldeman, 1840, included species, and related genera placed in synonymy, are reviewed. From among the 35 nominal species in this group, five distinctive species of Skolithos are recognized: Skolithos linearis Haldeman, S. verticalis (Hall), S. magnus Howell, S. ingens Howell, and S. annulatus (Howell). Specimens of Skolithos, vertical burrows made by such animals as annelids and phoronids, commonly in sandy sediments, are widely distributed in Lower Paleozoic and younger rocks, and are indicative of shallow wate