San Cassiano Formation.
229 million years ago, at the beginning of the Karnian stage, when volcanic
activity had ceased, in the Cortina d'Ampezzo basin and surrounding areas,
a relatively deep (300 â€“500 m) tropical sea environment was recreated, dotted
with coral reefs just below the surface of the water.
In this tropical sea, reconstructed in a simplified manner in the picture at the bottom of the corridor to the left, calcareous mud and deposits of various types built up, including algae, single corals, shells (lamellibranchia, gastropods, cephalopods, brachiopods), sea urchins (Echinoids) and sea anemones (crinoids). These deposits, which subsequently produced â€śsoftâ€ť rocks like Marnes and marly limestone, are today known by the name of San Cassiano Formation.