In the Perda S’altari area, north of Fluminimaggiore, black shales of the Silurian Genna Muxerru Formation and limestones of the Devonian Mason Porcus Formation are exposed. The area is strongly tectonized, and poorly preserved fossils occur only in a few outcrops. Graptolites of Telychian and Rhuddanian age have been collected from the shales, whereas conodonts indicate the Lochkovian Icr. postwoschmidti and Ad. transitans zones. The problematic Eurytholia bohemica species is here documented from Devonian rocks for the first time outside the Czech Republic. A gradual transition between the Genna Muxerru Fm. and the Mason Porcus Fm. suggests an update to the lithostratigraphical scheme of the Silurian and Lower Devonian of SW Sardinia.
