The Upper Coralline Limestone (UCL) is the youngest lithological unit exposed onshore in the Maltese archipelago. It is of late Miocene age and considered to have terminated with the Messinian Salinity Crisis. The base of the unit is fine grained carbonates, often partially mixed with the underlying Greensand. These transition to alternations calcareous sands and coralline rich beds, the later constrconstracting bioherms. Near the top of the unit a few horizons host corals, The top of the unit is composed mostly of large benthic foraminifera rich cross bedded calcareous sandstones.
The UCL is exposed across all three islands of the archipelago. In Malta, it is present mostly on the western side of the island. Some of the best exposure are on the coastal cliffs near Manikata.
Farther reading
Pedley, H.M., 1979. Miocene bioherms and associated structures in the Upper Coralline limestone of the Maltese Islands: their lithification and palaeoenvironment. Sedimentology 26, 577–591. doi:10.1111/j.1365-3091.1979.tb00930.x
Pedley, H.M., 1976. A palaeoecological study of the Upper Coralline Limestone, Terebratula-Aphelesia bed (miocene, malta) based on bryozoan growth-form studies and brachiopod distributions. Palaeogeogr. Palaeoclimatol. Palaeoecol. 20, 209–234. doi:10.1016/0031-0182(76)90003-1