Further evidence includes copper and celts of nephrite, a type of jade, and marine shells, especially the shells of dentalium, a marine mollusk that forms a long tube from which beads can be fashioned. These were collected on the west coast of Vancouver Island and traded widely throughout western North America. Throughout the Jomon period, Japan was divided into several zones, marked by characteristic pottery styles, which cut across the main island of Honshu. These pottery zones likely represent regions of interaction. For the Natufians and Calusa, there is evidence of long-distance trade and exchange of resources such as stone for tools and shells for personal ornaments.
Political organization is key to social complexity.
In contrast, at least some complex hunter-gatherers had permanent systems of social ranking with marked differences in the status, prestige, and power of individuals and groups within the society. The pyramids of Egypt and the palaces of Rome clearly point to the existence of elites, but the chiefly families of the Northwest Coast did not leave such obvious monuments. At Prince Rupert Harbor in northern British Columbia, elite grave goods include copper items as well. The development of this elite was accompanied by the rise of warfare, indicated by the presence of weapons, fortifications, and skeletons with violence caused trauma. The existence of a standing Calusa army suggests that warfare played an important role in their history, though, in contrast with the Northwest Coast, there is presently no evidence for fortifications.