At the continental margin of the south-eastern Black Sea (near Georgian coasts) the continental shelf, continental slope and continental rise are highly dissected with submarine canyons and valleys. Some bathygraphic systems can be outlined where submarine canyons change into submarine valleys and further into deep sea channels of turbidity currents. Some morphometric data are given for largest submarine canyons and valleys, topography of their deep-sea parts being discussed. The presence of sand and gravel in the cores at the submarine valleys thalwegs (against the background of prevailing mud) confirms the conclusion about significance of turbidity current in the process of debris transport and modeling of continental rise topography in the region studied. The double nature of submarine canyons and valleys is emphasized-first, they are large erosional forms, second, and they are ways of debris transport to lower levels. The continental rise at the South-East of the Black Sea is proved to be an individual morphological unit, representing an accumulative apron formed with many coalesced fans of submarine canyons.

The paper briefly discusses various tectonic school concepts which deal with topographic features, geology and tectonics of the Western Alps. Main attention is paid to the plate tectonic theory in connection with the Alps formation under conditions of two large lithospheric plates collision (after J. Debelmas and Y. Bravard).

The paper describes special features of distribution and evolution history of the regional erosional planation surface (high pediments level) and correlative deposits dated in general from Late Pliocene and Eopleistocene. A problem of Neogene-Anthropogene boundary is discussed from geomorphological point of view. A significance of high pediments level is shown for the determination of lower limit of Eopleistocene.

Some new definitions and criticism of the «morphostructure» term are discussed. The cause of contradictions and uncertainty of the term appears to be on one hand the vagueness of geomorphic concept of the «form» and on the -other hand - of the «structure». The author proposes to distinguish «structural landforms» and to define the «morphostructure» as characteristics or assemblage of land surface elements which are conformable to structural forms of the earthcrust.

Comment to the article of N. A. Florensov "Concept of «morphostructure» and its evolution"

Late Cretaceous and Paleogene valley systems are described for Yenisei region of Siberia. Main valleys (those of Paleo-Yenisei and Paleo-Angara) have been reconstructed, as well as some of their tributaries. The main valleys are filled with thick series of grey alluvium. In valleys of smaller tributaries there are mostly mottled deposits, locally containing bauxites, proluvial and deluvial faces predominating there. The sedimentary series are mostly divided into two parts: the lower one corresponding to perstrative phase of alluvuim accumulation, the upper one-to constructive phase. Ore traces and bauxite deposits are found in the constructive alluvium in small rivers valleys.

Causes of sea floor changes within navigable depth of shelves are considered to be one of problems of navigation geomorphology. An importance is estimated of background of tidal currents, quasi-periodic and non-periodic active hydrometeorological factors. An experience is described of ocean and sea shelves subdivision according to their dynamics; following areas have been identified and discussed: areas of arctic ices, of storms of temperate latitudes, of stationary anticyclones, of tropical cyclones development and movement, of tropical moons sons and of eqatorial calmes. While the «dynamic areas» being discussed, main attention is paid to the cyclic character of hydrometeorological processes, which is to be taken into consideration if the floor changes are observed with a certain time interval. A model-scheme shows causal and indicator's interrelations.

From special autonomous apparatus Visual observations were performed and data of side-looking locator were recorded at considerable depth near Batumi. Besides large submarine canyons many lateral crests and valleys cut into mud layers were discovered. Landslides are frequent at steep scarps. Channels are very interesting where mud flows towards main bed of a canyon. Erosional, stepped and block dissection of the continental slope is described. Falls of mud (similar to avalanches) are likely to take place occasionally.

Landforms due to subsidence result from epigenetic increase in density of thick cover loess series. Their formation is controlled by subaerial relief-forming processes, i. e. erosion, piping, leaching, processes due to gravity, privation, abrasion and regelation. In the genetic sequence of negative landforms first are shallow saucer-like depressions and second-more pronounced basins. These forms affect hydrotechnique, industrial and civil engineering, housing and agriculture. Arable lands where the subsidence landforms appeared should be meliorated.

On the Urals area under consideration the drainage net has been found to change not less than four times since Oligocene Main causes of the drainage net changes were the ocean's transgressions and covering the valleys with sediments of transgression cycles. During each new stage the drainage net developed transgressively, following the basin level lowering.

Comparative studies of geographical (mainly cartographical) data on the Nile delta from antique manuscripts, mediaeval Arabian geographical works and descriptions dated from the XVII -beginning of the XIX centuries A. C. reveal main trends of the offshore delta evolution throughout the historical time. Results of the studies suggest, first, gradual elimination of the delta channels (from 7 at Herodotus time to 2 at present); second, drying western flank of the delta and increasing humidity of the eastern flank. The channels atrophy is likely due to increasing usage of the Nile water for irrigation purposes; western flank drying and eastern flank wetting may result from differentiated tectonics and changes of the flow pattern within the delta.

Differentiated character of the earthcrust recent movements within the Upper Kama drainage basin control the changes of the alluvium dynamic phases from instrative to constructive one downstream. The instrative alluvium is deposited where the river crosses positive morphostructure of the Upper Kama, the constructive alluvium-within the limits of the Middle Kama negative morphostructure. Local neotectonic uplifts have been identified considering their geological-geomorphic features and the Holocene alluvium composition. Most active young subsidence areas correspond to meridional reaches of the river which coincide with large deep faults in the earthcrust, therefore the basement blocks were active during Holocene. The results of the studies can be used for investigation of tectonics, recent movements, estimation of areas from oil and gas searches point of view as well as placers searches.

Professor Nickolay Jovanovich Makkaveev (to the 70th birthday)

Useful study of man-induced geological processes

The first summary of the Caspian Sea coasts and floor geomorphology

Structural-geomorphological trend in sea coast studies

Problems of geomorphology at the 3rd National Congress of Bulgarian geographers

Nickolay Nickolayevich Sokolov (obituary)