Broadly speaking, the Balkan Peninsula may be divided into four areas which geologically are distinct. There is a central region, roughly triangular in shape, with its base resting upon the Aegean Sea and its apex in Servia. On two sides this area is bordered by belts of folded beds which form on the west the mountain ranges of the Adriatic and Ionian coasts, and on the north the chain of the Balkans. Finally, beyond the Balkans lies the great Rumanian depression, occupied chiefly by undisturbed Cretaceous and Tertiary strata. The central region, although wedged in between two belts of folding, is not affected by the folds of either, excepting near its margins. It consists largely of crystalline and schistose rocks. The core is formed by the mountain masses of Rhodope, Belasitza, Perin and Rila; and here Palaeozoic and Mesozoic beds are absent, and the earliest sedimentary deposits belong to the Tertiary period and lie flat upon the crystalline rocks. Upon the margins, however, Cretaceous beds are found. The eastern parts of Greece are composed almost entirely of Cretaceous beds, but nevertheless they must be considered to belong to the central area, for the folds which affect them are nearly at right angles to those of the western chains.
In general, however, the central area is one of faulting rather than of folding, and the sedimentary beds sometimes lie in troughs formed by faults. Extensive volcanic outbursts occurred in this region during the Tertiary period. In the western folded belt the strike of the folds is N.W.-S.E., or N.N.W.-S.S.E. There are many local irregularities, but the general direction is maintained as far as the southern extremity of Greece, where the folds show a tendency to curve towards Crete. In the north, Carboniferous beds are present, and the Trias and the Jura take a considerable part in the formation of the chain. The Sarmatian beds are also involved in the folds, indicating that the folding was not completed till Pliocene times. In the south, the older beds disappear and the whole chain is formed chiefly of Cretaceous beds, though Eocene and probably Jurassic rocks are present. The Eocene beds are folded, but the marginal Pliocene beds are not, and the final folding seems to have taken place during the Miocene period. (For the Balkans, see Bulgaria.)
Area in sq. m.
Pop. in 1909
Croatia-Slavonia (south of the Save
Bulgaria (with Eastern Rumelia)
The Dobrudja (Rumania)
Bosnia and Herzegovina (Austria-Hungary)
Sanjak of Novibazar (Turkish)
Albania, Macedonia and other
For full details as to the physical features, natural products, population, customs, trade, finance, government, religion, education, language, literature, antiquities, history, politics, etc., of the Balkan lands, see Albania, Bosnia and Herzegovina, Bulgaria, Croatia-Slavonia, Dalmatia, Dobrudja, Greece, Illyria, Macedonia, Montenegro, Novibazar, Servia and Turkey.