The Swiss Jura is the mountain range lying northwest of the Swiss Alps. It consists of a series of parallel folds in the strata, forming together a plateau about 300 km long and 30 to 60 km wide. These folded ridges have in many places suffered transverse fractures, which, in the form of steep gorges, add greatly to the picturesque character of the landscape. The general height of the range is from 900 to 1’500 m.
More than 200 million years ago the area of the Jura Mountains was flooded by the primeval ocean Tethys. In the course of the following 65 million years, over 1’000 m of fossil-rich sediments were deposited here. The layer structure of this process can still be seen.