L'Etang des Royes. Foto/Photo: TES.

L’Etang des Royes

The Fen (l’Étang) des Royes and the quarry (Carrière) des Royes are two remarkable places in the Franches-Montagnes (Canton of Jura). The quarry for the extraction of marlstone owes its existence to the collision of the continental plates of Africa and Europe 230 million years ago.

The result was the Alps and the Jura, surrounded by seas. This limestone developed on the seafloor over millions of years. Fossils in the limestone bear witness to the presence of oceans.

The creation of the Étang des Royes is of considerably more recent date. It is a remnant of the last ice age, 10 000 years ago. The many water sources in the Jura also led to the formation of peat bogs.

As early as 1589, a grain mill powered by water power was located at the Étang des Royes. Today, it is a nature reserve without industrial activities.