La Drôme Departmental Council’s Areas of Outstanding Natural Beauty

This is a rare heritage site as the transition can be very clearly seen between two geological stages, the Valanginian and the Hauterivian. There are only a few places in the whole world that offer this opportunity so the Department of La Drôme decided to develop and equip this space.

This site is very fragile. Please stay within the specifically laid-out area, do not climb the cliffs and do not take any fossils – thank you!
Since its “discovery” in 1977, the Serre de l’Ane site, near La Charce, has been the subject of numerous studies and its renown among geologists now stretches around the entire world. Indeed, this is an inestimable heritage site as the transition can be very clearly seen between two geological stages, the Valanginian (139 million to 134 million years ago) and the Hauterivian (134 million to n131 million years ago). This is what you will be able to discover all along this hill and its elongated shape (the “serre”) as it takes you back in time over several million years.
There are only a few places in the whole world that offer this opportunity and so the Department of La Drôme decided to develop this site to make its exceptional features known to a great many people.You will find several interpretation areas that will enable you to learn more about the site:
- La Terrasse, (The Terrace) to observe and understand the broad landscapes that surround us;
- Le Chemin des temps géologiques, (The Geological Time Trail) to present some of the rudiments of geology and help you understand the geological phenomenon before your eyes;
- Le Jardin des fossiles, (The Fossil Garden) to display replicas of fossils found by geologists on the site and nearby.This site is very fragile. It is important to stay within the specifically laid-out area. Do not climb the cliffs (risk of rock slides) and do not take any fossils as it is extremely informative for scientists to study them in-situ in order to learn more about our history. It is in everyone’s interest. Thank you for abiding by these guidelines.The Serre de l’Ane site has been equipped thanks to partnerships between the Department of La Drôme and the town of La Charce, the tourism development association of Baronnies Provençales, the Val d’Oule Centre and Lyon Geology Laboratory. Project owner: the Department of La Drôme
Project manager: Itinéraire Bis (Bertrand RETIF) and Virginie DU JEU
Works contractor: the company LIOTARD
Interpretation circuit: Alp’Com / Kaliblue / Ducaroy Grange

Les Baronnies Provençales has many stories to tell about the history of the planet Earth if you know how to interpret the signs given in the land and rocks.The first took place during the Mesozoic or “middle life” era (also called the Age of the Reptiles). The region was then covered by a sea at the bottom of which sediments formed. Most of the strata in Les Baronnies date from this period.
The second story to unfold relates the history of tectonics: the northerly drift of the African plate led to east-west folding of the earth’s crust.
Then there is the current chapter in this story: the formation of the Alps. The landscape was again subjected to major compression which caused the rocks to fold deeply. Deep faults fractured the hardest rocks to form north-south cols and valleys (like the Oule Valley).
Finally, the last story to be told is the one that is taking place in front of our very eyes: erosion by water, ice and wind. Les Baronnies Provençales has many stories to tell about the history of the planet Earth if you know how to interpret the signs given in the land and rocks.The first took place during the Mesozoic or “middle life” era (also called the Age of the Reptiles) between 250 million to 85 million years ago. The region was then covered by a sea of varying depths. This was a period when sediments formed on the sea bed. These sediments, originating from an area south of the Massif Central, sometimes formed marlstone and sometimes limestone beds and sometimes alternating marlstone and limestone beds, like at Serre de l’Ane. Most of the strata in Les Baronnies date from this period. Marlstone can be found nearby at Arnayon, Montréal-les-Sources and in the Ennuye valley.The second story to unfold relates the history of tectonics: the northerly drift of the African plate led to east-west folding of the earth’s crust (between 45 and 35 million years ago). The hardest of the previously-formed limestone layers became the summits of Les Baronnies, and likewise, in the region of La Charce, formed the Duffre ridge and the Raton and Angèle Mountains.Then there is the current chapter in this story: the formation of the Alps, an ongoing process. The landscape was again subjected to major compression which caused the rocks to fold deeply, like at Saint-May and the Col de la Pertie (between Villeperdrix and Arnayon). Deep faults fractured the hardest rocks to form north-south cols and valleys (like the Oule Valley). These movements created thrust faults in which lower and older rocks were pushed up and exposed gypsum beds from which plaster is made (Propiac, Lazer, Montbrun-les-Bains).Finally, the last story to be told is the one that is taking place in front of our very eyes: erosion by water (creating gorges and limestone pavements with their clints and grykes), erosion by ice and glaciers (creating, to the east, the Durance and Buech valleys) and erosion by the wind.