The structure, stratigraphy, and orogenic history of a large area of the Apennines northwest of the Apuanes massif (Italy) was studied and it was concluded that a large portion of Tuscany is occupied by an autochthonous platform and by the Tuscan nappe. The nappe, with basal upper Jurassic to middle Cretaceous beds, overlies Oligocene and possibly Miocene formations of the autochthon. Both nappe and the stable platform area are overlain by sedimentary beds of the Ligurian series.