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Vistula valley betiueen the outlets of Dunajec and Breń

cular bends. Actual depressions are almost always wet although to a va~ rious degree. Oxbow lakes are preserved in some of these depressions. point bars are fiat and the characteristic crescent-shaped ones are not pronounced either on aerial photographs or in the terrain.

Overf lood terrace II B. The abandoned channels occurring on this terrace possess slightly larger radii of curvature, of 370 m at ave-rage. A diversity of their bend curvatures being a characteristic feature causes that these channels are not so regular as those on the terrace II A. Point bars are freąuently fiat, without the definite slopes in cer-tain cases, hence it is sometimes impossible to separate them from the channel tracę. This terrace forms only isolated fragments close to the river channel (Fig. 1) located 1—1.5 m lower than the terrace II A.

Overf lood terrace II C. The overflood terrace II C, as the terrace II B, occurs in a form of isolated fragments in a rangę of paleo-meanders of the largest radii of curvature up to 700 m provided the channel width of 300 m. The majority of these paleomeanders are ir-regular, sometimes with well pronounced traces of a channel migration.

One of these paleomeanders was undoubtedly active still in the 17th century what is indicated by a map of Michałowski (1678). The rema-ining paleomeanders are included here due to their geometrical affinity and direct neighbourhood with the lower flood plain.

The position and character of some indistinct bend-like traces markę d on the aerial photographs close to the .Dunajec mouth are questio-nable in that approach.

The present surface of the overflood terrace was being formę d sińce the Atlantic period until the 17th century AD. The age limits are deter-mined by the ¹⁴C dates of the bottom of the abandoned channel fills. The dates 6040 ±140 BP (Gd 2274) and 3970 ±80 BP (Gd 1793) to the north of Szczucin, 3270 ±200 BP (Gd 2293) in Szczucin and 4920 ±220 BP (Gd 2292) near Mędrzechów have been obtained. The tree trunk stuck in the channel deposits of the point bar in Słupiec has been dated as of 4920 ± 100 BP. The upper limit was determined by the above mentioned map of Michałowski (1678).

FLOOD PLAIN (III)

The flood plain forms narrow benches on the both banks of the pre-sent-day Vistula channel. In order to distinguish this flood plain the di-verse relief of the surface, recognized from the aerial photographs and topographic maps (comp. Falkowski 1967 and Szumański 1972, 1977), has been adopted as a criterion.

The abandoned channels associated with a meandering river activity