During the Paleogene, the warm and wet climate favored the formation of lacustrine zones. In the Ardèche, platelets limestones at the limit of the Gard, at Orgnac L’Aven, attest of the plants and fishes presence of that time.
Bolca Mount site (Italy)
In the north of Verona, Mount Bolca is one of the first fossiliferous sites known in the 16th century. The quality of conservation of marine tropical fishes is unique. It is one of the most important Eocene deposits.
Megalodon
The largest of all the cartilaginous fishes that had existed roamed the seas from 28 to1.5 M.a. The fossils of teeth and vertebrae studied suggest that it looked like the great white shark, greater and stockier.
James-St.-John_Wikipedia