This formation consists of counters of metric thickness, hence the “massive" appearance that gave rise to the name. The massive limestone, in fact, is distinguished from the formations that follow it in the stratigraphic succession which are all stratified in a more or less intense way. This formation represents the only example, in the Umbrian-Marche Apennines, of a “thin sea" Carbonate Platform, that is, of shallow waters. The sedimentary environment in which it deposited about 200 million years ago was similar to what we can currently find in the Bahamas archipelago: large lagoons with shallow waters (10/15 m), tidal flats, islets, bars and coastlines, corals and algae. The Massive Limestone gives rise to very picturesque and imposing-looking landscapes, such as the Gola del Furlo, the Sasso della Rocca on Mount Nerone, and the Frasassi Gorge.