This paper deals with the lithostratigraphic correlation of the Ordovician–Silurian succession between the Baltic, Podlasie and Lublin basins, located on the SW slope of the East European Craton. The correlation is based on previous lithostratigraphic classifications, which are modified here to include the results of recent biostratigraphic and sedimentological work performed on several new wells. The authors propose to extend the Sasino Formation for the entire upper Darriwilian–lower Katian mudstone sheet that is traceable in all basins. It is recommended that the Jantar Bituminous Claystone Member (late Hirnantian–Aeronian) of the Pasłęk Formation be elevated to the rank of formation and the name Pasłęk Mudstone Formation be retained for the late Aeronian–Telychian, rhythmic alternations of black, laminated mudstones and greenish, bioturbated mudstones. Moreover, the authors suggest that the top of the Kociewie Formation (Sheinwoodian–Ludfordian) be placed at the upper boundary of the Reda Member (latest Ludfordian), which shows much wider lateral persistence than previously was thought.
