settlements of Tredici and Sette Communi, where German customs, folklore, language, and German types of faces still persist, survivals from the days of German infiltration across the Brenner Pass.[371] [Illustration: SLAV-GERMAN BOUNDARY IN EUROPE.] [Sidenote: The Slav-German boundary.] Where Slavs and Teutons come together in Central Europe, their race border is a zone lying approximately between 14 and 24 degrees East Longitude; it is crossed by alternate peninsulas of predominant Germans and Austrians from the one side, Czechs and Poles from the other, the whole spattered over by a sprinkling of the two elements. Rarely, and then only for short stretches, do political and ethnic boundaries coincide. The northern frontier hem of East Prussia lying between the River Niemen and the political line of demarcation is quite as much Lithuanian as German, while German stock dots the whole surface of the Baltic provinces of Russia as far as St. Petersburg, The eastern rim of the Kaiser's empire as far south as the Carpathians presents a broad band of the Polish race, averaging about fifty kilometers (30 miles) in width, sparsely sprinkled with German settlements; these are found farther east also as an ethnic archipelago dotting the wide Slav area of Poland. The enclosed basin of Bohemia, protected on three sides by mountain walls and readily accessible to the Slav stock at the sources of the Vistula, enabled the Czechs to penetrate far westward and there maintain themselves; but in spite of encompassing mountains, the inner or Bohemian slopes of the Boehmer Wald, Erz, and Sudetes ranges constitute a broad girdle of almost solid German population.[372] In the Austrian provinces of Moravia and Silesia, which form the southeastward continuation of this Slav-German boundary zone, 60 per cent. of the population are Czechs, 33 per cent. are German, and 7 per cent., found in the eastern part of Silesia, are Poles.[373] An ethnic map of the western Muscovite Empire in Europe shows a marked infiltration into White and Little Russia of West Slavs from Poland, and in the province of Bessarabia alternate areas of Russians and Roumanians. The latter in places form an unbroken ethnic expansion from the home kingdom west of the Pruth, extending in solid bands as far as the Dniester, and throwing out ethnic islands between this stream and the Bug. [Illustration: ETHNOGRAPHICAL MAP OF RUSSIA. MONGOLOID: Kalmucks, Kirghis, Nogai, Tartars, Bashkirs, Voguls, Ostiaks, Samoyedes. ZIRIAN: Mingled Mongoloid and Finnish.] [Sidenote: Assimilation of culture in boundary zones.]