The term formation was first introduced into geological literature in 1762 by the German scientist G. Füchsel to designate a complex of strata formed under similar conditions. Since then, the term has been widely used by American geologists as one of the basic units of local stratigraphic subdivision. Most Soviet geologists, led by N. S. Shatsky, understand formations as certain lithologic parageneses of rocks. Other geologists, led by V. V. Belousov, associate formations with certain stages of the geotectonic cycle ...