Initially, the lava was very acidic but later became basaltic, spreading in large, fluid flows that covered the slopes of the structure.

The landscape of the Planèze is characterized by gentle slopes, prompting people to plant numerous groves of pine trees.

Significant prehistoric settlement in the region is evidenced by the presence of numerous megaliths in Allanche, Joursac, Coltines, Valuéjols, Paulhac, Villedieu, Seriers, and Les Ternes.

[3] Until the city of Saint-Flour was founded in the 11th century on Rocher d'Indiciat, the capital of the Planèze region was Valuéjols, whose name attests to its Gaulish origin.

[4] Several Gallo-Roman sites have been discovered, notably a villa at Puech de Frayssinet, which underwent rescue excavations by Alphonse Vinatié in 1980.