In several localities of the Puy-de-Dome department (Central Massif, France) fluvial deposits with pumice, ash, and volcanic minerals outcrop. Study of the mineral composition of these outcrops establishes close analogies among them and makes it possible to tie in their volcanic minerals with a single period of acidic activity of the Mont-Dore volcano. The mammalian fauna in the contemporaneous alluvium is middle Pleistocene; paleomagnetic determinations and K/Ar dates on the flows verify this age.