The Grottes du Cerdon (Cerdon Caves) are located near Labalme, in the French Jura. Inhabited by prehistoric humans (evidence suggest from 10-12,000 years ago), the caves were used to store their game and keep it fresh, due to the cool and constant temperature. The trip to the caves starts with a small train, which takes you the entrance of the cave.
The Grottes du Cerdon visit continues on foot from the top entrance, following a dry river bed which descends deep underground.
The path winds through many calcareous concretions (stalagmites, stalagtites, draperies and eccentrics), formed by water seeping through the limestone.
The path continues to descend deeper towards a large cavern; there’s some evidence of rockfalls caused by secondary branches of the main (now dry) river.
The narrow passage opens up to an enormous cavern, known as “La Fromagère”. Created by water erosion from the river causing a huge amount of rock to cave in, it was use in prehistoric times for food storage. The name of the huge cavern is derived from a local cheese-maker in the 1930s who decided to mature his Blue de Gex cheeses here. Using a winch to lower and raise the cheese and a small cart on rails, cheeses were stored here until the 1950s. The temperature in the cavern never exceeds 4 degrees.
The path through the Grottes du Cerdon continues further down the steepest section to the sump, which is 125m below the entrance to the cave.
A huge opening or porch opens up at the end of this last cavern, providing a vista over the blind valley and town of Cerdon and the surrounding karst cliffs.
It’s then back up to La Fromagère where we exit the cave; just before we leave we see a group of cavers, who offer Luke a mini-caving experience!