Plio-Quaternary continental deposits have an important role in the new Geological Map of Italy at 1:50.000 scale (CARG Project). The Geological Survey of Italy suggests mapping such deposits through the unconformity-bounded stratigraphic units (UBSU), after adaptations.
In this work, examples from different areas in northern Italy and Sardinia are analysed and compared. The results are: a) a standard rule for use of the UBSU is not applicable; b) the UBSU provide a tool for regional or interregional syntheses only in a few cases (e.g. in the large sedimentary Po basin), while for minor basins (e.g. the alpine valleys) they represent a local meaning; c) consequence problems in hierarchy and correlation of units of neighbouring areas occur also.