Noordelijke zwerfsteenkoralen (6) Lavendelblauwe verkiezelingen (2)

Investigation of silicified erratic palaeozoic corals from the Mid-Pleistocene 'White Sands' in the NE part of the Netherlands shows, that the Favositidae are the most common fossils, immediately followed by some genera of the Heliolitidae. The remaining species found were Sarcinula LAMARCK, 1816; Catenipora LAMARCK, 1816; Multisolenia FRITZ, 1937 and Cryptolichenaria SOKOLOV, 1955. Within the Favositidae the genus Palaeofavosites TWENHOFEL, 1914 is predominating. In all collections examined they constitute more than 80% of the determined Favositidae. Mesofavosites SOKOLOV, 1951 is present too, although in rather few specimen. Of the genus Favosites LAMARCK, 1816 only two small specimen have been found. The composition of the Heliolitidae, in which Proheliolites KIÄR, 1897 and Propora M. EDWH., 1849 predominate and the remaining non-favositid genera, such as Sarcinula, Catenipora and Cryptolichenaria indicated an ordovician age. A competitive examination of the erratics of Palaeofavosites with the estonian species described by E. KLAAMANN (1964) showed clearly an ordovician age for the first, too; in contrast with the erratic Palaeofavositidae from the Saale boulder clay of Groningen and Haren, that all most likely are of silurian age. With the exception of very few finds of silurian species (Favosites,Heliolites, Plasmopora, Multisolenia) other silurian corals have not been found.