Geological mapping and fades analysis of the Jurassic-Lower Cretaceous units located around the La Cantalera fossil site (Josa locality, Teruel Province, NE Spain), has allowed a precise reconstruction of a continental sedimentary basin developed around the Hauterivian-Barremian turnover. The first stage of evolution of the basin was controlled by intense normal fault activity and resulted in the formation of an isolated basin, surrounded by limestone-marly relief. The existence of a non-permanent water marshy area, with an important vegetated area, explain the abundance and diversity of the fossil remains in the studied locality