The forms and deposits in this chamber indicate the key stages in the history of the cave. Following its excavation by submerged water flow responsible for the ceiling pendants, the morphology and sedimentation were influenced by phases of flooding and drying out, some of which are linked to the regional geological history marked by the variations in the level of the Mediterranean.
The subsidence depressions have made it possible to give a detailed description of the recent evolution of the chamber, marked by two interlocking collapses: the first created a depression which was at least partly filled after 130,000 years because it contains remains of Ursus spelaeus and is sealed by white concretions dating from 27,800 to 7,700 years ago. The second led to the present-day morphology.
The cave was mostly colonised by bats, the source of the phosphates that colour the floors grey, and by bears whose presence alternated with that of humans. The humans frequented a chamber with fewer concretions than today, and a clay floor, as was the case throughout the whole of the cave. However, the stalagmitic floor had begun to form when the Gravettians were present in the cave. The latest subsidence post-dated the human occupations, as is indicated by the engravings on the pendants hanging over the void. The study of the pollens reveals the existence outside the cave of steppe vegetation, with a few trees in sheltered areas.