[6] Later acknowledging the ambiguity in that system as well, he published a new classification in 1869, using type sites and their associated artifacts to distinguish and name periods: (Chellian, Mousterian, Solutrean, Magdalenian, Robenhausen).

However, whereas Mortillet believed his classifications were universal stages, with a unilineal evolution, later thinking regards each culture as a more localised conglomerate, capable of overlapping in time with others, not necessarily lineally related.

[8] Mortillet proposed the name "Marnian Epoch" as a replacement for the period usually called the Gallic, which extends from about five centuries before the Christian era to the conquest of Gaul by Caesar.

Rames discovered flints at Puy Courny which triggered debate on the presence of ancestral humans in the Miocene, and the new genus and species Homosimius ramesii was proposed by de Mortillet.

[11] His hypothetical genus gained another species, H. bourgeoisi, from the Oligocene of Thenay, France based on similar flints[12] and exhibited by Abbot Bourgeois at the International Congress of Anthropology and Prehistoric Archaeology hosted in Paris, 1867.

[16] However he was unable to accept the authenticity of the much more extensive cave art that was coming to light, conservatively and stiffly rejecting Sautuola's discovery of the paintings in Altamira as the original work of Paleolithic man.