In the improved climatic conditions at the end of the 31st century, the local population grew, agricultural lands took up more and more space, and cultural traditions underwent rapid change.

This was a period of general growth in the populations of cultivators. Chalain and Clairvaux witnessed the successive arrival of groups of dwellers from Horgen—with their flat-bottomed pottery—and from Ferrières, with their decorated round-bottomed pots.

To understand these expansions—followed by the phenomenon of acculturation between the local population and the new arrivals—examining cereal crop yields can help establish a link with the climate.

Distribution of pottery styles.