These rolling hills are clearly visible from the main N-240 road near Barbastro. They are unique in character as they are gypsum-based in comparison to the majority of the substrate of the area, which is mainly sandstone and clay. As gypsum is a soft rock, the landscape here is made up of gentle peaks and flat valleys where a build-up of fertile lime helps the cultivation of crops.

The plants here are gypsum-tolerant; these are more common on the Ebro Valley plains and relatively unusual in Somontano.