Early large borings in a hardground of Floian-Dapingian age (Early and Middle Ordovician) in northeastern Estonia (Baltica)

Large plug- or slightly amphora-shaped borings have been found in the hardground marking the boundary between Early and Middle Ordovician rocks in northeastern Estonia. These borings cut large bioclasts of the trilobite Megistaspis and cannot be assigned with certainty to any known ichnotaxon. They indicate that the diversity of early borings may have been greater than was recognized previously.