A walk through dry zones, then humid ones, on the Mechmont plateaux and through the cool, quiet Vert valley. The Gigouzac crocodile - steneosaurus - whose fossil remains were discovered in 1948 by a geologist from the Lot lived in the region about 150 million years ago. Its body was covered with bony plates and its lower jaw was 1m 23 cm long. The region was then a marshy coastal area opening on to a sea linking the Paris basin, England, Belgium, Germany and the Languedoc. In these warm waters, numerous living organisms flourished.