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By the use of thinner and heavier Lines in the map a very plastic and measurable image was created. Erosional cuttings of the moraine plateau and the dimensions of eroded forms are shown very distinctly.

A separate symbol indicates the zonę of slope denudation along erosional escarpments, embracing edge zones of destruction (soil erosion) as well as shelves of colluvial deposits and minor alluvial cones at valley floors, at the foot of an erosional escarpment.

At times, instead of colluvial deposits there occur gentle flattenings at the foot of slopes of denudational character. Where slopes have undergone-far-reaching degradation, a symbol for gentle denudation slopes is applied.

The most important divergence from the method normally applied in maps of geological-morphological type for distinguishing forms of direct glacial accumulation is the classification applied here for forms of the morainic plateau; this classification takes into account both the above mentioned morphographic features and the morphogenetic cate-gories corresponding to these features. The morphometric features of the relief simultaneously given in the map make it possible to define the differences in height of plateau forms and to determine the pre-dominant inclination of their forms. In this manner we are enabled to compare the landforms of successive glaciations in Poland as well as the degree of alteration subseąuently suffered by these landforms.

The present classification of landforms of the Polish Lowland omits the term: end moraine. This is due to the viewpoint that hummock and hill forms observed on a plateau within the area of the Last Glaciation— unless produced by dead ice — usually show features of marginal forms. Even an undulant moraine plateau, provided its differences in height appear zonally or are morę or less genetically connected with chains of morainic hummocks or hills, has the features of a marginal character. The above data may be supplemented by suitable explanations and frag-mental maps showing the author’s view on some detail of the geomorpho-logical map.

The differences in height of landforms of direct glacial deposition are stated in the map with regard to the height of the fiat moraine plateau as level reference.

The extreme differences in height observed in the Polish Lowland, extending from the bottom of sub-glacial channels or ioe-marginal streamways to the top of the most important marginal deposits of the inland ice, exceed at times 200 meters.

The present cartographical image of the relief of the Polish Lowland, comprising the categories of landforms enumerated below (67 items in all), is the result of many years research and numerous debates. The content of this map is steadily increasing in data given and the number of distinguished landforms is constantly being augmented. At the same time, the geomorphological map is continually growing significance for a thorough analysis of the relief of a region, preventing one-sided inter-pretations of landforms and unadvantageous restriction of the proble-matics of geomorphology, while assisting in preparing auxiliary maps for purposes of scientific study and use in the field.

Each sheet of the geomorphological map is supplemented by a text containing, inter alia, geological and morphological sections across the

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4 — Problems