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Holoceńskie doliny a wielkie zamknięte baseny w Polsce

ciał channel there are represented both the Niczonów and Objezierze cross-sections. Niczonów was interpreted (Kopczyńska-Żandarska 1970) as a riv-er valley of Mazowian age with the valley floor lying at 150 m b.s.l. How-ever, the author of the paper disagrees with fluvial valley origin interpretation. It is most probably rather a subglacial channel from one of the older glacia-tions (Sanian 2 ?).

Objezierze (Skompski 1994) is an example of subglacial channel of Vis* tulian age completely infilled by glacifluvial deposits of the same age, and about 160 m thick! This channel is visible in the present glacial topography. It is a typical subglacial tunnel valley according to description of Kozarski (1966/1967) and Niewiarowski (1995).

Unquestionably major Pleistocene river valleys in the Polish Plain are a prolongation in the northern direction of such a valleys developed on the northem part of the Mid-Polish Uplands, where they are very well recognised