An integrated study including magnetostratigraphy, larger benthic foraminifera and calcareous nannofossil biostratigraphy is presented herein. This work was performed in shallow marine siliciclastics rich foraminifera, around the Ypresian/Lutetian boundary Ésera valley (South-Central Pyrenees). Although content studied interval low, not allowing a precise Y/L to be recognised, taxa found are en...