The Monte Bolca deposits, abundantly fossiliferous, were formed in a lagoon which was separated from the open sea by coral reefs. At that time,
in the Eocene, a tropical climate prevailed and there was considerable volcanic activity. The volcanoes on the nearby mainland erupted periodically, their lavas and ashes covering the land for some time. But volcanic gases also
rose from the off-shore sea-bed, producing a marked increase in the temperature of the water and poisoning it at the same time. Many fishes and other marine organisms came to an untimely end, were embedded in the soft mud of
the seabottom and were buried beneath further sedimentation. In these deposits, finally petriefied and now raised by orogenic (mountainbuilding) movements to 600 metres above the sea, fossils have been turning up for more than
200 years. The fishes, some 160 different spezies, are the best preserved of these; traces of their vivid colouring occasionally remain.
Original: Museum of Natural History, Verona, Italy