This can be seen not only from the fact that river basins are inhabited by a single tribe or people, but also, for example, from the relations which existed in former times between Greece, Ionia, and Magna Graecia, between Brittany and Britain, between Denmark and Norway, Sweden, Finland, Livonia, etc.; it is also particularly clear when we contrast this with the lesser degree of contact between the inhabitants of coastal territories and those of the interior.