ing 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 [v.03 p.0259] 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 and Population_.--The following figures show the area and population
of the various political divisions of the Balkan Peninsula in 1909; see
also the articles on the separate countries.

Pop. per
Political Divisions Area in sq. m. Pop. in 1909 sq. m.
----------------------------------------------------------------------
Croatia-Slavonia (south of the
Save and Kulpa) . . . . (about)8,200 (about)1,200,000 146.3
Servia . . . . . . 18,782 2,493,770 132.2
Bulgaria (with Eastern Rumelia) 37,240 4,028,239 88.
The Dobrudja (Rumania) . . 5,896 258,242 43.9
Dalmatia (Austria) . . .