Abstract <p>The Middle and Late Devonian paleosols (Voronezh and Belgorod oblasts) and Carboniferous paleosols from the southern flank of the Moscow Basin (Moscow, Tula, Kaluga, and Ryazan oblasts) have been studied in detail using a set of analytical methods. The mineral composition of the studied paleosols has been shown to be, with few exceptions, monomineral. The Devonian continental sediments and paleosols developed from them are characterized by kaolinite, rarely by berthierine composition. Early Carboniferous paleosols are composed of low-charge smectites: montmorillonite and beidellite. In the Middle and Late Carboniferous, there is an increasing role played by Mg-silicates: palygorskite and sepiolite. This series is due to changes in the paleogeographic environment and in climatic zonation, and to global climate aridization. The monomineral character and the absence of mixed-layer minerals fundamentally differentiate the Paleozoic paleosols from the Quaternary paleosols and modern soils developed from sedimentary rocks. The polyminerality of the latter is a product of the recycling of sediment and soil material from past epochs.</p>