Originally, the steeply rising limestone slab was a horizontal, lime sludge-covered beach of a tropical sea. Dinosaurs strolled up and down the coast and left their footprints. Algae covered and thereby protected them, followed by numerous additional layers of lime sludge. The weight of these layers triggered their fossilization and pressed the rocks downwards.
More than hundred million years later the Jura Mountains were formed. Giant sheets of fossilized sediments were pushed up and heaped on top of each other. When the limestone slabs were quarried, the layer with the tracks was exposed. In 1987, the ‚elephant tracts’ were identified as footprints of plant-eating dinosaurs, such as Brontosaurus.
Since then, many more dinosaur tracks have been found at different places in the Jura Mountains; see for example here.