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Nowe poglądy na rozwój rzeźby rasowej

conditions experienced no major changes during the Tertiary and Quaternary periods. The karstic forms of those regions are a product of the same climate which obtains there now. Attempts at deciphering the karstic relief within a temperate (middle latitude) climate will be possible only following an investigation of the relief typical of the regions mentioned. The areas which now have a temperate climate were characterised by dry and humid climates during the Tertiary period. During the Quaternary, on the other hand, they had a cold climate (in glacials) and a temperate climate (in interglacials and postglacials).

The karstic areas lying within that climatic belt were thus modelled sińce the Tertiary period in various climatic conditions. In connection with this fact it is necessary to ascertain in those areas (incl. Poland) the course and the time of formation of individual karstic forms on the basis of a knowledge of leading forms characteristic of hot and cold areas, as well as of present karstic processes and of fresh Holocene forms, now being created in a temperate climate.

Having presented the results of investigations on the karst relief within the climatic belts mentioned above, the author touches upon certain problems of karstic geomorphology in Poland. Particularly interesting are the problems concerning the origin and age of the degradation plains within the Upland of Cracow and of the peculiar monadnocks protruding from that plain. Those monadnocks have aroused interest for a long time (27, 37, 39, 45), but it was rather difficult to ascertain their origin. Their distribution shows that they are not typical erosional remnants situated along watersheds, and their geological structure does not warrant the view of their being strućtural hard knobs. Probably they are “Mogots” characteriistic of tropical lands, sińce subtropical climatic conditions existed in Poland during the Paleogene period. It is necessary to investigate those forms and to ascertain whethea: they possess the Mogot fe-atures quoted in the first part of this work. The problem is not so simple. They underwent a long metamorphosis, especially during the Pleistocene period, not only by the periglacial processes, but also by the inlandice of Cracow glaciation.

The origin of monadnocks is closely connected with the problem of the genesis

and age of the degradation plain which was considered as a wave-cut (abrasional)

platform of the Cenomanian seas or as a surface degraded by denudations agents.

When the monadnocks are shown to be “Mogots”, the saurface may be recognized as

a karstic degradation plain. The rock surface has not been reconstructed so far, but

the observations madę by Pokorny and Walczak have shown that it contains a vast

depression and smali geological organs filled with preglacial deposits such as:

variegated clays, sands, boulder clays containing flints and quartz pebbles. It is

obvious that the karstic plain was covered by a thick (10 metres) mantle of

impervious, alluvial and residual deposits even before the Pleistocene period,

6imilarly as the bottoms of marginal 'pLains and central poljes known within the tropical regions. Those deposits are covered by the Pieistocene mantle consisting

mainly of loesses.

The surface of the Jurassic limestone may have been subjected to karstic processes during the whole Tertiary period, but these processes were especially intense in the Paleogene.

This is evidenced by an outcrop at Kurdwanow near Cracow, recently described by M. Tyczyńska (41). Here the surface of Jurassic limestone is strongly corroded by deep karstic holes and covered by residual deposits (clays with flints). The lower Tortonian deposits lying above them indicate with accuracy the geological age of this post cretaceous surface.