Provides rhythmostratigraphic characteristic of Lower Permian halogen formations of Western monoclinal part of the North-Caspian halmeic basin. Paleogeographic conditions of accumulation of potassium and magnesium and magnesium deposits in the Volga Monocline and the southern deadlock part that holds Gremyachinskoe deposit and related search sites: Darganovskiy and Ravninniy are considered.