Gastrochaenolites ornatus Kelly and Bromley 1984 occurs on the sub-Cretaceous unconformity surface and intra-Cretaceous omission surfaces in the area of Brand ́s nad Labem (central Bohemia). A variety of substrates (Proterozoic shales, Ordovician claystones and siltstones, and poorly lithified Cenomanian sandstones) were affected by the same biogenic activity. Considering the mode of construction and reservation of trace fossils, all can be considered as firmgrounds. Some specimens contain tracemakers preserved in situ, represented by thick-ribbed molluscs (cf. Myopholas sp.).