soils that are found in the mountains and that belong to almost all the soil types known on earth. The distribution of mountain soils is subject mainly to a vertical (elevation) zonation; the soils change with ascent into the mountains depending on changes in climatic conditions. Like soils in level areas, mountain soils are subdivided into tundra, podzol, brown-forest, gray-forest, chernozem, chestnut, brown semidesert, sierozem, brown, red-earth, yellow-red ferralitic of humid tropical forests, solonchak, marshy, and many other soils. Most mountain soils form on very steep slopes where, as a result of denudation processes, their shallowness, gravel-like quality, and wealth of primary minerals may be observed. The large amount of primary minerals makes intrasoil weathering very important in the formation of mountain soils, especially in warm, humid climates where weathering is quite intensive. Mountain soils are characterized by an extensively developed slope (lateral) flow of soil moisture owing to the considerable steepness of the slopes and the high water permeability of the gravel-like rock masses. These features of mountains soils, together with the uniqueness of the relief conditions under which they are formed, make it necessary to distinguish them from soils in level areas and to identify them on soil maps as mountain tundra soil, mountain red-earth soil, mountain chernozem, and so on.
V. M. FRIDLAND