A sounding carried out in the sediments of La Roche-Cotard II (9 sedimentary layers) revealed a level of occupation (in layer 7) dated from the Mousterian of about 0.20 cm thick. It consists of three areas: a bowl to the west, a small pile of tools to the southeast, and a poorer area to the east. The bowl measures about 0.40 m in diameter and 0.15 m thick. Dug into the yellow sand resulting from the alteration of the tufa, it contained a rib of a large herbivore. It corresponds to the location of a fireplace (rubefied sand). The coast was dated in 1980 to the ¹⁴C to an age greater than or equal to 32,100 years (Gif 4383). Some tools (scrapers) were found around this bowl. The pile of flint tools in the southeast consisted of Levallois blades and a few splinters. Further east, the area corresponds to a peripheral dump-type space. It was among splinters and sketches of bone that a block of local flint called "the mask" was discovered.

The absence of very small chips and the virtual absence of small chips, as well as their diverse origins, indicate that flints were not cut on-site. The site can therefore be considered as a camp of Mousterian hunters.

In 2009, two new ¹⁴C dating performed on bones belonging to the same sedimentary layer as that of the mask indicated an age greater than 40,000 years.

In 2014, optically stimulated luminescence (OSL) sediment dating proposed the age of 75,600 years +/- 5800 for the layer containing the mask.

In 2023, a multidisciplinary study, led by geologist Jean-Claude Marquet, is carried out in the cave. New dating confirms that Neanderthals are the authors of digital tracings discovered in 1975.