The Mesozoic sediments have been deposited in largescale basin areas. During the Triassic, the Franconian part of these depressions was often part of the mainland, in the Jurassic it was covered for most of the time by a marginal sea of the western Tethys Ocean. At the time when the limestones and dolomites of the White Jura were being deposited, this sea was divided into sponge reefs and intervening lagoons. The reef bodies and the fine-grained lagoon limestones and marls are the material from which the majority of the Franconian Jura is composed today. Following a drop in the sea level towards the end of the Upper Jurassic, larger areas also became part of the mainland at the beginning of the subsequent Cretaceous period. During the Upper Cretaceous, the sea advanced again up to the area of the Franconian Jura. At the end of the Cretaceous, the sea then retreated again from the region. In addition, large parts of South and Central Germany experienced a general uplift -or in areas where the basement had broken through a substantial uplift - the course of formation of the Alps during the Tertiary. Since then, Franconia has been mainly influenced by erosion and weathering (especially in the Jura in the form of karst), which has ultimately led to formation of today's landscapes.