A scattered location results in all stages of civilization when an expanding or intruding people begins to appropriate the territory of a different race. Any long continued infiltration, whether peaceful or aggressive, results in race islands or archipelagoes distributed through a sea of aborigines. Semitic immigration from southern Arabia has in this way striped and polka-dotted the surface of Hamitic Abyssinia.[268] Groups of pure German stock are to-day scattered through the Baltic and Polish provinces of Russia.[269] [See map page 223.] In ancient times the advance guard of Teutonic migration crossed the Rhenish border of Gaul, selected choice sites here and there, after the manner of Ariovistus, and appeared as enclaves in the encompassing Gallic population. While the Anahuac plateau of Mexico formed the center of the Aztec or Nahuatl group of Indians, outlying colonies of this stock occurred among the Maya people of the Tehuantepec region, and in Guatemala and Nicaragua.[270] Such detached fragments or rather spores of settlement characterize all young geographical boundaries, where ethnic and political frontiers are still in the making. The early French, English, Dutch, and Swedish settlements in America took the form of archipelagoes in a surrounding sea of Indian-owned forest land; and in 1800, beyond the frontier of continuous settlement in the United States long slender peninsulas and remote outlying islands of white occupation indicated American advance at the cost of the native. Similarly the Portuguese, at the end of the sixteenth century, seized and fortified detached points along the coast of East Africa at Sofala, Malindi, Mombassa, Kilwa, Lamu, Zanzibar and Barava, which served as way stations for Portuguese ships bound for India, and were outposts of expansion from their Mocambique territory.[271] The snow-muffled forests of northern Siberia have their solitudes broken at wide intervals by Russian villages, located only along the streams for fishing, gold-washing and trading with the native. These lonely clearings are outposts of the broad band of Muscovite settlement which stretches across southern Siberia from the Ural Mountains to the Angara River.[272] [See map page 103.] [Sidenote: Political islands of expansion.]