DSC07939 (2)

T. Sokołowski

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are actually used by the Breń river in the Southern part and by the Strumień Channel in the northem part. They are occuppied by the thin and discontinuous mada layer (Fig. 1, 9) in contrary to the remaining part of the terrace, being sandy at the top.

The terrace surface is covered with dunes which, in majority, form ridges para Ud to the valley direction. The height of this terrace sub-stantially increases between Opatowiec and Nowy Korczyn due to accre-tion by several meters thick loess layer, the lat ter developed in the valley facies, with a layer of the fossil soils of the Komorniki type (Jer-sak 1976) at the bottom.

The age of the terrace is difficult to be determined. Undoubtly, it was still fragmentarily formed during the younger Pleni-Vistulian what is indicated by the ^UC datings in the rangę of the analogical form in the Dunajec valley (Sokołowski 198lb) and in Opatowiec (Alexandrowicz, Jersak in press). The presence of the higher socle near Olesno and of the erosional troughs indicates that the fossil forms which formation could have reached the Middle-Polish Glaciation are masked in the terrace.

OVERFLOOD TERRACE (RENDZINA) II

The younger and lower overflood terrace is inserted into the middle terrace. Its extent is determined usually by the paleomeander traces. If the middle terrace is undercut by these paleomeanders the border separating those two levels is distinct, of a naturę of bend-like fairly steep scarps. When they are lacking the border is uncertain, sometimes formed by a gently inclined Iow slope. In such a case the lithological limit between the madas on the overflood terrace and sands on the middle terrace was the criterion for distinguishing.

A variability of the terrace width is interesting. The latter is 2.5— 4.5 km in the western part near Opatowiec and Nowy Korczyn. Farther to the east it narrows to 3 km, then to east of Szczucin it doubles its width reaching 6.5 km.

The paleomeanders within the area of the discussed terrace do not form so differentiated generations as those observed by Szumański (1972, 1982) in the San valley. The radii of the abandoned channels as well as their widths are similar. However, their division was attempted on the basis of certain changes of their naturę distinguishing also 3 patches of the overflood terrace (A, B, C).

Overflood terrace II A. This terrace of the largest area occurs close to the Vistula channel and in the peripheral parts. The radii of the abandoned channels vary from ca. 150 to 630 m, ca. 330 m at ave-rage. The channel widths are 40—160 m. The change of their curvature is very uniform what results in regular channel forms, resambling ci»