Basally developed 'reef pioneer settlement', some 10m in thickness
dominated by densely packed Stachyodes and auloporids in a black bituminous limestone matrix. This sequence passes into
dark-grey fossil-rich limestones with special rugose coral consortia dominated by Mesophyllum and Stringophyllum. A thin horizon
(approximately 30-50 cm) with small colonies of the phaceloid rugosan Thamnophyllum terminates the 'pioneer sequence', which is overlain by 20-30 m-thick, white and slightly dolomitized limestones. The latter contain accumulations of various reef-building organisms
(stromatoporoids, rugose and tabulate corals).