3. From 35 million-years to Oligocene (*), Bages was a continental basin with rivers that loaded it with sediments and lakes at which bottom limestones can be originated. This continental sedimentation resulted in the reddish detrital rocks (mainly mudstones and sandstones ) of the west, north and center of the district. These materials cover the previously deposited evaporites and the materials of marine origin.
The gravel sedimentation was kept in Montserrat and Sant Llorenç del Munt.
(*) The age of the most modern rocks of the Bages Oligocene is not accurately known and there isn't any proof of further sedimentation during Tertiary. [drawing Oriol Oms]