In 2015 the remains of a large marine reptile dating from the end of the Cretaceous period were discovered in the Chartreuse Park by an amateur paleontologist who immediately alerted the Park's services. They are vertebrae belonging to the group of mosasaurs.
Commissioned by the Park and under the leadership of Patrick Gardet, Hélène Fournié was to shed light on one of the possible scenarios of the life of this mosasaurus.
Moreover, how to explain to the general public that this specimen, which died about 80 million years ago, could be found in a geological layer "lower" than the cave bears, which lived in the "Balme à Collomb" about 25,000 years ago?