By examples from Tertiary of Mecklenburg and Brandenburg (G. D. R.) fossilisation of traces from boring bivalves in wood is investigated. There are shown relations between the sculpture of wood and the sculpture of outside wall of borings. This kind of foreign sculpture is exceptional distinctive by cor preservation of Teredolites Leymerie 1842. The annual rings of boored wood can be the dominant texture-element, so that the true nature of borings is hidden.