Feuerstein-Typen der Oberkreide Helgolands, ihr stratigraphisches Auftreten und ihr Vergleich mit anderen Vorkommen in NW-Deutschland

Boulders of sediments from submarine outcrops of Upper Cretaceous beds are continually washed up on the beach of the island of Dune, Helgoland. Many flint concretions are found here which can be assigned to several distinct types according to their morphology, surface pattern and colouring or colour zonation. Determination of megafossils in these boulders and investigation of coccoliths in the associated chalk provide information about the stratigraphic range of the flint-bearing beds. The results make possible a provisional correlation with other flint occurences in the Northwest German Upper Cretaceous.