Existing classifications of river channels are critically revised. No uniform classification of mountain, semi-mountain and plain rivers is shown to be worked out as yet. Many channel types identification is based on the formal description, the same approach is used to mountain rivers typology and to plain rivers, without consideration of special features of the channels formation, principles for channels identification are often different, and many schemes are inconsistent in their internal structure.

A new classification of river channels is introduced, which includes all the variety of morphological features resulting from channel-forming activity of both plain and mountain rivers. Types, sub-types and species of channels are distinguished according to their morphology and especially to special features of their changes' regime. The classification's structure allows to enlarge it in the course of the channel processes study progress.

A general scheme of genetic-dynamic classification is introduced for the landforms which came into being at the contact between ice and bedrock. Subglacial landforms may be presented as a continuous sequence as the rate of ice movement decreases, one type of movement changes into another and the mechanism of the relief formation is subsequently altered. Several large groups of subglacial origin are distinguished, i. e. those due to static extrusion, slow viscous-plastic flow, intensive viscous-plastic flow, expiration topography formed by ice-blocks sliding, as well as landforms due to erosion by subglacial pressure water.

Useful component concentration is mostly controlled by the channel type of the placer-forming stream. The placers are thin and less steady in mountain streams and more thick and steady in semi-mountain rivers. The layer's thickness essentially depends on the stream slope as well as on the mineral particles size.

The layer's parameters and the mineral's distribution in the alluvium change along with the erosion-sedimentation activity of the stream. The bedrock surface morphology also controls placer's structure and mineral particles distribution.

Three approaches exist to the «morphostructure» concept," which is considered to be: a) geologicak manifested in the topography, .b) landform due to tectonic movements (interacting with external processes), c) part of the land Surface which as a whole changes its position with respect to neighbour parts (due to tectonics). The last definition: a) is most general and includes the two others as particular cases taking into consideration all the variety of morphotectonic forms, b) most closely corresponds to the object of geomorphology and structural geomorphology in particular, c) lays within the limits of the latter methods possibility and contributes to its progress.

Authors try to systematize principles of subdivision of topographical surfaces («faces») on the basis of logical rules of classification. Definitions of «newly formed surface» and «genesis of surface» are given. The classification is supposed to be used for geomorphological legends.

The Tier Shan slopes reveal clearly steps which are fragments of orogenic surfaces of planation differing in ages and corresponding to erosion cuts which can be traces into mountains interior. Highest and oldest surfaces were repeatedly glaciated during Quaternary. The ancient relief was not however completely destroyed. It is accounted for by special features of the expiration process in mountains as well as by the fact that erosional dissection of each higher step is controlled by the base level position that is by lower step. Therefore the stepped structure of mountain slopes itself provides for conservation of the steps-the ancient topographic elements-everywhere, including heavily glaciated areas during Quaternary.

Distinct hierarchy of landforms is indispensable for every kind of geomorphological studies. The authors introduce the Earth's landforms classification (especially morphostructures) based on size and genesis and appropriate for space images interpretation. Parameters (length, depth) are given characterizing morphostructures of different classes; types and scales of space photographs are recommended which are the best for their identification. An importance of system approach to morphostructural analysis is emphasized.

Many paleo-geomorphological concepts (including conclusions on origin and age of planation sutfaces, interfluvial areas etc.) are based on some ideas about importance and type of denudation processes. In the Eastern Carpathians like in most part of middle mountains a set of denudation processes works: water stream and mudflows, mass movement, avalanches, biogenic processes, wind action, splash erosion, chemical denudation. Stationary observations of the processes during several years allowed to estimate the processes intensity and total value of the material removed by denudation.

Sedimentation of the Visean terrigenous series at the Udrnurtian territory was analysed from the paleogeornorphological point of view. For Malinovian, Bobrikovian and Tula ages paleogeomorphological schemes l:500000 were drawn, based on sediments thickness, the latter being reconstructed considering sediments compression, sand content etc. Main geomorphic features of the area can be described for Visean age on the base of the investigation carried out, and zones can be outlined promising for non-anticlinal oil and gas deposits.

A choice of the best scale of morphometric maps to ensure sufficient reliability with less labour is vital while working out nature-conserving measures and rational use of resources within vast areas. Studies of main morphometric maps-large scale maps of slopes-show that general distribution of slopes of different steepness is sufficiently characterized at the maps scale 1:10000, 1:25000 and 1:50000. Total cartographic error in area measure does not exceed 4%. The mean value of slope can be precisely estimated. Nevertheless the maps l:25000 and l:50000 may bring about great errors if used to erosion prediction and planning of soil conserving measures, as the cartographic generalization in these scales results in slopes distortions. If the total area is about 0,5 sq. km the errors in slope definition may be 17% and more.

Space TV images (made by «Meteor» satellites) have been interpreted and two systems of dislocations - Pravoberezhnaya and Volynskaya - were identified within plain Ukraine. The systems are pre-conditioned by geomorphic features of the area. Teсtonics was main f actor during the uplands formation. The author gives evidences the uplands to be formed by crustal tangential stresses directed from S and SW. Distinct character of geomorphic features at the photoes proves the stresses are active up to now.

A close connection is underlined existing between mudflows and landslides formation, various features and evolution of ground masses 'in terms of mud -flow processes, methods of complex studies are described in details including geological, hydro -geological, hydrological and landscape studies. An importance of remote sensing (space photographs etc.) is emphasized for landslides and mudflows studies as well as experiments. Mapping technique is recommended, and methods of stationary observations are proposed.

Erosion of an ancient volcanic caldera (Pacific coast of Southern Kamchatka) resulted from climatic changes and the World Ocean level fluctuations. 10 terraces and topographic levels correspond to time intervals favourable for terrace formation, their absolute ages are as follows (thousand years): floodplain, Q²₄ - 4 to 4,5, 1st terrace, Q¹₄- is to 7,5; II, Q³⁽¹⁾₃ - 25; III, Q₃³⁽²⁾ - 35; IV, Q₃³⁽¹⁾ - 45; V, Q₃¹⁽³⁾ - 75-80; VI, Q₃¹⁽²⁾ - 105; VII, Q₃¹⁽¹⁾ - 120-130; VIII level, Q₂²- 165-190; IX level, Q₂¹ - 200-400.

Large volume of cartometric works and the data processing revealed a connection between neotectonic structures and deep structures as well as neostructural control of ore formation at the vast territory of the North-East of the USSR.

Neotectonics analysis can be used for metallogenic studies in order to single out mineral deposits.

V. P. Zenkovich - founder of the Soviet school of coastal geomorphology

To the jubilee of Oleg Konstantinovich Leontyev