Tiber Valley
The Tiber Valley (Italian: Valle del Tevere) is the largest geographical part of the Tiber basin of the Tiber river included in the Emilia-Romagna, Tuscany, Umbria, and the Lazio regions; it is characterized by river terraces and floodplain areas that extend from the Apennine belt up to the delta of the Tiber river in the Lazio coast of the Tyrrhenian Sea. == Geology == The Tiber basin is made up of four main morpho-structural environments: the upper Tiber basin, composed mainly of terrigenous sediment in flysch facies of Tuscan origin (on the right bank north of Lake Trasimeno) and Umbria-Marche (on the left bank) the Apennine carbonate ridge, which occupies the eastern and southern sector, made up of carbonate reliefs; the Tiber graben with its marine to continental facies deposits, the intermountain basins; the volcanic systems of the Volsini Mountains, Cimini, Sabatini and Alban Hills, which occupy the southwestern sector.