During geological mapping of folded areas, the geologist-surveyor constantly has to face the question of dissection and correlation of sedimentary deposits containing remains of fossil organisms of poor preservation or not characterized by them at all. In small-scale geological surveys, well-known features are used for this purpose: similarity and difference in lithology; degree of metamorphism; nature of folding; relationship with intrusions of a certain complex; any characteristic features of the selected sediment complex, if these features are syngenetic with these sediments and therefore relate only to them (oblique layering, presence of nodules of various kinds, etc.).