Paleontological investigation of the Oligocene beds in the Tertiary Aurillac basin (France) provides evidence that at the type locality--Puy de Vaurs--the marly limestones are in the upper Stampian, the gravelly shale being attributed to the lower Stampian, a conclusion confirmed by the stratigraphy of neighboring regions in the Saint-Flour basin and Limagne. The tuffs at Pont-de-Gail--southern flank of Cantal--which contain an upper Miocene mammalian fauna, probably correspond to the first eruptive phase of the volcano. A long period of continental alteration followed, succeeded by a second eruptive phase. This was followed by quartzose sedimentation and andesitic intrusion. A new foraminifera species, Caecilianella aurillacensis, is described from the upper Stampian at Puy de Vaurs.