South of the Aubrac region, the Grands Causses are several limestone uplands: there are seven “main” causses and many other little ones. On the way to Saint Guilhem, you will walk on some of these causses: first, on the Causse de Sauveterre and the Causse Méjean (two of the “main” causses). Then, after having crossed the Cévennes, you will find the Grands Causses region again, with the Causse de Blandas and the Causse du Larzac.
These causses are separated from each others by valleys and gorges. On the route, you will see the Gorges du Tarn and the Gorges de la Jonte: the Tarn separates the Sauveterre from the Méjean, and the Méjean is delimited in the South by the Jonte. In the south, the gorges de la Vis mark the limit between the Causse de Blandas and the Causse du Larzac.
The Causses can be described as a dry area with a typical landscape: dry grasslands with nevertheless a remarkable flora. Many species of native wild orchids bloom there; Carline (Carlina acanthifolia) and Orphan maidenhair (Stipa pennata) can also be found.
On the causse, the economy is based on sheep rearing. Animals are reared for meat but also for milk, which is used to make local cheeses.
Man has shaped the landscape: dry stone walls along the roads and as limits between land parcels; clapas (heaps of stones that have been removed from a field that will be cultivated)… Dolines are small depressions with clayey and fertile bottom where grain and forage can grow.
A cazelle is a little shelter in drystone built by shepherds to protect from sun and wind when they looked after their flock. It was built with stones picked up on site.
The caussenarde houses are made of limestone: stone walls, flagstones on the floor, lauze roofs. Tanks lay next to the houses for gathering rainwater when it falls on the roof.