Selected sections, containing Devonian/Carboniferous boundary beds, are described from the northern and northeastern margin of the Rhenish massif, especially from the Seiler region near Iserlohn and the Warstein area. These sections are from prospecting trenches, quarries and road cuts.
The dominantly carbonate sequences were investigated in regard to the development of conodonts. The Devonian/Carboniferous boundary could be placed precisely in both areas by means of the phylogenetic transition from Siphonodella praesulcata to S. sulcata. Compared investigations lead to the following conclusions:
- The basal part of the Hangenberg limestone is heterochronous.
- The Devonian/Carboniferous boundary lies distinctly below the Hangenberg limestone, i. e. at the same stratigraphical level as the Stockum limestone.
- The Imitoceras limestone lens of Stockum and the Stockum limestone represent a special facies within the Hangenberg schists. 80th belong either to the praesulcata- and sulcata-zone or are restricted only to the sulcata-zone.
- Protognathodus kuehni appears together with Siphonodella sulcata. Where S. sulcata is lacking, P. kuehni may be considered as a valid index conodont indicating the beginning of the Carboniferous.
- The upper part of the Wocklum beds, following above the Wocklum limestone, usually consists up to the lower Carbonilerous boundary in a more or less consistent facies, that of the Hangenberg schists. Only in the section 01 the northeastern wall of the eastern Provincial Quarry at Drewer and in the road profile Rüthen - Nuttlar, the Devonian/Carboniferous boundary is to be placed in a continuous carbonate sequence.
- The eastern Provincial Quarry at Drewer is therefore proposed as a new candidate section for the Devonian/Carboniferous boundary stratotype.
- In many places the carbonates at the Devonian / Carboniferous boundary and the Hangenberg limestone are characterized by an impoverished conodont fauna.
- Using platform conodonts, biofacies models are developed, permitting to conclude on the position of the respective setting 01 sedimentation area, either close to a rise or a basin.
