The base of the Frasnian Stage which coincides with the base of the Upper Devonian is defined at the base of Bed 42' at Col du Puech de la Suque section E in southeastern Montagne Noire, France. The GSSP also coincides with the lower boundary of the Lower asymmetricus Zone which is defined by the first occurrence of the conodont Ancyrodella rotundiloba.
The GSSP section is located at Col du Puech de la Suque section E in southeastern Montagne Noire, France. The section is located on the eastern slope of the hill 358, about 50m ENE from the crest, at 1.1km SE of St. Nazaire-de-Ladarez (1:25 000 Sheet St. Chinian, x = 660.67, y = 133.95).
Section E is characterized by a sequence of predominantly red and grey pelagic calcilutites, punctuated by hardgrounds that are mainly in the part of the sequence above the boundary level.
The GSSP coincides with the first occurrence of the conodont species Ancyrodella rotundiloba.
There are 5 conodont associations recognizable in the section. In ascending order:
The goniatites Probeloceras and Petteroceras feisti first appear low in the Lower asymmetricus Zone.
Conodont FAD Ancyrodella rotundiloba