Trace Fossil Preservation in Flint in the European Chalk

Prominent horizons of concretionary flint in the chalk of Europe typically represent silicified burrow systems. Ichnologic information may be preserved in three dimensions (either as the external form of the flint or as cavities within it) or two dimensions (as sculpture on this flint, representing the surface expression of ghost structures silicified within the flint). Thalassinoides suevicus is the most commonly silicified trace fossil in chalk, generally preserved as a replacement of the burrow fill. Bathichnus paramoudrae typically is unsilicified but is encircled by ring-like paramoudra flints. Other trace fossils (e.g., Chondrites, Muensteria and Zoophycos) occasionally occur in flints. Thus, flints can be employed as a means for observing the nearly invisible ichnofabric of the chalk in which the concretions formed.