Rare tool marks from the Upper Ordovician of Estonia (Baltica)

Tool marks from the Upper Ordovician of eastern Baltica are here described for the first time. These tool marks are composed of relatively large sets of thin regular parallel ridges. They are similar to the ‘Eophyton’ tool marks from the Cambrian of Sweden. They also resemble tabulate groove marks from the Upper Ordovician of the Cincinnati, Ohio, region of North America. Most likely these tool marks were produced by linear sweeping across the sediment of tabulate corals or crinoid stems. The rarity of tool marks in the carbonate rocks of the Ordovician of eastern Baltica indicates rarity of sedimentation environments favourable for their formation.