It preserves fossils dated to the Paleogene period (latest Bartonian to Late Oligocene),[1][2] or MP16 to MP28 zones of the European land mammal age classification, ranging from approximately 38 to 25 Ma.

It qualifies as a Lagerstätte because beside a large variety of mammals, birds, turtles, crocodiles, flora and insects, it also preserves the soft tissues of amphibians and squamates, in addition to their articulated skeleton in what has been called natural mummies.

The first geologic investigation of the formation was performed by Thévenin in 1903, and apart from a description by Gèze in 1938, the paleontological richness was not studied until a team of researchers of the Universities of Montpellier and Paris visited the site in 1965.

[7] The Quercy Phosphorites Formation is a highly fossiliferous unit designated as a Lagerstätte due to the excellent preservation of fossils.

The phosphorite conserves up to the nerves, digestive tract and stomach content,[8] insect larvae and other elements of the paleobiology in the formation.