I have purposely gone somewhat minutely into the gold-fields of ancient Gaul, and the story of the sacred treasures. For I think that no one who considers carefully the statements of Posidonius, Strabo, and Diodorus, can help regarding as wholly inaccurate the conclusion of Schrader, based on the Irish word or, that the Keltic peoples were not acquainted with gold until the fourth century B.C. The sacred treasures point to a ceremonial consecration of gold extending back through untold ages.
It must also be borne in mind that in the treasure of Tolosa there was a good proportion of silver which probably came from the silver mines mentioned by Strabo57 as existing in the land of the Ruteni and Gabales (Γαβάλεις), two peoples of Aquitania, whose names are represented by the modern Rovergue and Gevaudan. As the working of silver is so much later than that of gold, it is impossible to believe that if the Gauls in Italy only learnt the use of gold in the 4th century B.C. we should find consecrated treasures of silver, evidently of ancient date, at Tolosa in the time of Servilius Caepio. It is also important to observe that it is among the Iberians of Aquitania, not the Kelts, that we find silver mines being worked. The former people were entirely free from Roman influence, and we shall see shortly that there is the strongest evidence for believing that the Iberians south of the Pyrenees were acquainted not merely with gold but with silver, centuries before ever Brennus stood in the Roman Forum.