The Combe de Mortiès is the most complete geological series in the entire Bas-Languedoc region and, as such, a reference site for stratigraphers and paleontologists.
This site is therefore well known for its Lower Jurassic fossil deposits. Probably too well known, as only a few very small ammonites can still be found there...
Regarding the vineyard soils, two main origins coexist in some places and overlap in others: on one hand, soils resulting from the erosion and alteration of the Lias marls (Lower Jurassic, -180MA), in which the combe was carved out, and on the other hand, contributions of gravelly-stony deposits from the erosion of the limestones forming the surrounding hills and ridges. Thus, the complexity of the distribution and variability of these soils result from successive phases of erosion and contributions from the Pic Saint-Loup reliefs.