The Mszana Dolna and Szczawa tectonic windows are composed of deposits belonging to the Fore-Magura Group of units. The central and most uplifted part of these windows are dominated by relatively flat laying deposits belonging to the Krosno Formation (Oligocene) of the Dukla Unit. The western, eastern and southern marginal parts of the Mszana Dolna tectonic window are occupied by strongly tectonized, Cretaceous-Oligocene deposits assigned to the Grybów Unit. The Szczawa tectonic window is entirely built up of Oligocene deposits of the Grybów Unit. The youngest deposits of the Mszana Dolna tectonic window are correlated with zone NP24 (Dukla Unit) and NP23-NP25 (Gryb6w Unit). In the Szczawa tectonic window (Grybow Unit), the NP22-NP24 Zone was determined in the Grybow Beds, whereas the Cergowa Beds belong to zone NP24. Such age determination corresponds well with that of the southern part of the Silesian and Dukla units. The deposits of the Dukla and Grybow units are tectonically covered by the Cretaceous-Eocene deposits of the Magura Nappe. During the latest Oligocene a thrusting of the Magura Nappe onto the Fore-Magura sedimentary basin began (Grybów and Dukla). This process was probably initiated under the submarine condition. The last of the over thrusting stages took place probably during the Middle Miocene, and resulted in the development of the Mszana-Dolna duplex structure.