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rctchiiif condiuions conccming cithcr thc prcvalenee or absence oi somę. of deposit. Howcvcr, it is notcworthy that a part from their types deposits n? wcre probably la id down by thc braided rivcrs during thc Youngcr Pleuig^^ show somc festures in common: eithcr a well defined bcdding (J? dcposits) or laminat ion (channel fi U deposits and ovcrbank deposits), as eaceptionally finc grains. Similar observations have bccn madę by E Mytk ska-Dowgiałło (1978) and by T. Sokołowski (1981) in thc Vistula valłcy wńw thc Sandomierz Basin.

The present writer has found that in the valleys of both thc Wisłoka and upper Yistula thc tcztural properties of the different types of depo^ dat mg from various periods of both thc Vistulian and thc Holoccne are on of all relation to the period of sedimentation (age of depos^ Similarly the textural properties of deposits do not reflect the influence of different elements of the geographical milieu. The propertiesof dcposits accumuiated in the mountain foreland. being expressed by both grain size index and quartz grain abrasion index, are determined by the hydro, dynamie conditions prevailing in the difTerent depositional subenvironments Deposits accumuiated in both dynamie current environments (channel deposits) and non-current environments (overbank deposits) are well defined. The highly yariahle sedimentary conditions are reflected in channel fili deposits and in alluvial fan deposits.

M an‘s impact is dearly reflected in the channel deposits which accumuiated during the youngcr Subatlantic period. Only these deposits do differ from thc remaining fossil sediments, and they show the greatest variations in grain sizes.

Both the morphoselection of quartz grains and the successive phases of reworking of the materiał by the river during transport tend to influence thc inerease in abrasion degree and homogeneity as regards abrasion in the subsequently younger channel deposits.

Aeknowłedgemenis* This work was done in the Department of Geomorphology and Hydro-logy. Institutc of Geography and Spatial Organization. Polish A ca demy of Sciences in Graco* under the supervision of Profcssor Dr L. Starkcl. It is a product of rescarch for the CPBP program 03.13 “Evolutk>n of the geographical environment of Poland". 1 would like to thank Profcssor Dr L. Starkcl for helpful advice during fldd work and preparation of the m&nuscript. 1 also am grateful to Profcssor Dr K. Rotnicki for permission to use the automatic graniformameter, for interest a my work and for helpful advice. I am indebted to Mrs M. Klimkowa for both her commentsootfc illustrations and their drawing. Mgr H. Witański. Dr A. Łajczak, Mgr Ing. J. Gradowski, Mgr A. Polińska and Mgr Ing. A. Podgorska-Tkacz are thanked for their assistance with fioki aod laboratory work. i.e. for making the grain size analysis.

REFERENCES

Allen J. R. L, 1965, A mww of the origin and characteristics of recent jlłuvial sedmm. Scdimentology 5, 89—191.

Alexandrowicz S. W,* Klimek K.. Kowalkowski A., Mamaków a K.. Niedziałkowski R, Pazdur M.. Starkel L, 1981, The evolution of the Wisłoka railey noar BfMct krttf A Late Glacial and Hołocene, Folia Quater. 53.

Antczak B.. 1986. Transformacja ukhhiu koryta i zanik Hfttrkocji Wtarły. Wvd. Nauk. V’AM.Ser. Geogr.. 35.

Brakenridge G. R.. 1984. Alhtrial strtitigruphy and ndiocarhon dating ałong the DmA rh* Tennessee: Impłicathms regarding jlm\ł~f'htin origin, Gcol. Soo Am. Buli. 9S» 9—25.