Final answer:
Jacques de Perthes attempted to prove the existence of a prehistoric period by studying ancient tools and fossils in the Somme Valley in northern France.
Step-by-step explanation:
Jacques de Perthes was a French archaeologist who attempted to prove the existence of a prehistoric period through his study of ancient tools and fossils. He believed that these artifacts were evidence of an ancient human civilization that existed before recorded history. De Perthes conducted excavations in the Somme Valley in northern France and found stone tools alongside fossilized animal bones. He argued that these tools were made by ancient humans during a time when the climate was warmer and the region was inhabited by now-extinct animals.