ABSTRACT

In the "Nellenkopfchen-Schichten" (Lower Devonian, upper "Unterems") at locus typicus near Koblenz, river Rhine, investigations were made of genesis, structures, bedding types, marks and traces. An undisturbed, complete profile of more than 60 m thickness exists in this area.

The "Nellenkopfchenschichten" are compared with modern sediments of the same environment: southern part of the North Sea, German Bay.

Nellenkopfchenschichten continuously had tidal environment and shallow water, an environment with strong reworking and rapid geosynclinal subsidence. Channels, sand bars, and tidal flats are the morphological symptoms. All changes within the sediments and structures are explained by the change within morphology. typical for these environments. There was no change in the water depth from shallow to deep water. The subsidence of sea bottom was compensated by a strong supply of sediments and their redistribution by tidal currents and waves.

A wide communication with the open sea is necessary for palaeogeographical explanation.

No steep coastlines existed nearby, but in the north there must have been flat shore environment. In the south there must have been open sea.