Complex sentence: Moreover, no material remains of any Corsicans have been found or excavated, the tombs are unlike those of Volterra, and finally, between Populonia and Volterra, the former was by far the major settlement.
Split into simpler sentences: Moreover, no material remains of any Corsicans have been found or excavated. And finally, between Populonia and Volterra, Populonia was by far the major settlement.