The sandstones and mudstones from continental Eocene in Bages district may be crossed by thin layers of fibrous gypsum. This gypsum was originated after sedimentation by precipitation in crevices of calcium sulfate from water. These gypsum thin layers are frequent in strata of El Guix (= gypsum in Catalan), a neighborhood near the capital Manresa where the pictures were taken.
The growth of the gypsophile shrub Ononis tridentata in the district of Bages usually relates to the presence of gypsum layers.