Part of it is made of basalt and volcanic ashes. The wine estate is situated at the north-west of Vias, separated from the sea by an old volcano, Roque Haute. Pierre Paul Riquet, who built the Canal du Midi, used the volcanic stone to built the structures along the Canal from Villeneuve les Béziers to Agde.
The rest is clay and gravel… The Preignes’s gravel terraces correspond to the old alluvium of the Libron, brook which crossed the wine estate. More information :
stones pulled out of the Cévennes a hundred thousand years ago, during the big rising periods, notably during the last interglacial warming. Rolled by the water a long way, they became pebbles and then rounded gravels. Their deposits of several meters of thickness, hardly liable to deterioration by the rain and the wind, protecting inferiors geological horizons, emerged progressively due to the landscape’s erosion.