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of the raw materiał charactcristic for particular mines can be distinguished. Varieties of striped flint occur in various regions of Central Europę. Striped varieties are found among Jurassic-Cracow flints, Cretaceous erratic flints (Baltic ones) and Volhynian flints, as well as flints and hornstones from Bavaria. Among them, striped flint of Krzemionki is the most decorative one, which can be clcarly distinguished in this respect from all other Europcan flints.

In the region of the Holy Cross Mountains grey white spotted flint was exploited at the Świeciechów minę on a big scalę. Świeciechów is Iocated on the right bank of the Vistula river close to Annopol (Balcer 1975, 46-52; 1976, 179-186). The cortcx is white, soft, and of various thicknesses (Fig. 10). White piaty Turonian marls are the bed rock of Świeciechów flint. But their eluvial deposits were the first ones to be exploited. Flint from Ożarów similar to Świeciechów flint was of the local significance (Krzak 1970).

In the Cracow region, south of the Polish Jura, Uppcr Jurassic flints called Jurassic-Cracow flints were com-monly exploited. They occur in situ in the Oxford malm limestones. But there is no evidence to show that they were exploited there in prehistorie times. The biggest Jurassic-Cracow flint agglomerations are known from the Tertiary eluvia! deposits, from the area of the Pa-leogene surface of plantation in the Southern part of the Polish Jura (Lech 1980). In some deposits of Karstic clays, flints constitute approx. 50% of the wholc forma-tion (Fig. II). Jurassic-Cracow flints occur as nodules of various sizes, sometimes forming a hornstone Iayer up to 3 m long. The most freąuentły exploited deposits in the eluvial clays providcd nodules from a few centi-metres to approx. 30 cm (Fig. 12). The colour of the siliceous mass is most often from brown to black, fre-quently grey, less freąuentły bluc and morę seldoni whitish. Some varieties of this raw materiał, after ex-posure on the surface for a few years, change in colour from dark brown to grey. The surface becomes duller. The cortex of the Jurassic-Cracow flint is usually uneven, spiked with the thickncss from approx. 1 mm to a few millimetres. Some varicties of the Jurassic-Cracow' flints popular among early farming communities have brown, chocolate colour identical with some varictics of “choc-olate” flints. Clearance (a kind of suspension), gloss and the kind of cortex are the criteria allowing them to be distinguished by mcgascopic method.

Cretaceous flint and cherts occurring in the Cracow region had little significance there (Kaczanowska, Kozłowski 1976, 207 f.).

In the whole area of the North European Plain, from the Vistula river basin at the east to the Rhine and Maas at the west, Cretaceous erratic Senonian flints are found. Towards the south they appear in the upland