Searched by Edouard Lartet until 1847, it was considered useful for Science and is registered by the Inventaire national du Patrimoine Géologique (InPG) as an international-level site.

[1] The National Museum of Natural History bought 4 hectares (9.9 acres) of terrain in 1848[2] and oversee any research on the site since then.

[3] The paleontological site is located inside the commune of Sansan, on the Campané hill at 238 m (781 ft) above sea level, in the Gers department, 16 km (9.9 mi) south of Auch.

[6] A 2.5 km (1.6 mi) trail, marked by interpretive panels, helps to teach how Edouard Lartet discovered the site and how his discovery revolutionized the scientific theories of the time and exposed the richness of its Miocene fauna and flora.

One of the most important discoveries on the site was the description by Edouard Lartet in 1837 of Pliopithecus, a catarrhini monkey, which was a keystone in the reject of creationism by scientists and the advance towards the evolution theory.