New information from borings shows that in the region to the west and north of the Lons-le-Saunier basin, France, the Jura border is thrust over the Tertiary of the Bresse region. The age of the movement is post-Pontian, and the amplitude over five kilometers at certain points. The movement occurred along gypsum and salt zones in the lower Keuper and Muschelkalk (Triassic) without disturbing the underlying Triassic, Permian, and Carboniferous beds.

A compilation of reports on the geology of the Jura mountains, with particular reference to structural features and outcrops observed during the field trip of the French Geological Society in the region in 1951.