The Dynów Marls occur in the lower part of the Menilite Beds throughout the Carpathian Arc. These siliceous marls record decreasing salinity, anoxic bottom conditions, and pronounced endemism during the Lower Oligocene age (Nannozone NP 23), referred to as the Solenovian Event (loss of connection of the Paratethys with the world ocean). Until recently, these beds, and the rest of the Menilite Beds in the Outer Carpathians, were considered to be a product of deep-water sedimentation, rather than shallow-water sedimentation as interpreted, for example, in Austria and the Czech Republic. To explain this discrepancy, detailed sedimentological studies of the Dynów Marls were undertaken in the south-eastern part of the Silesian Nappe of the Polish Outer Carpathians, in three selected sections: A – in Gorlice; B – Zborowice; and C – Jabłonica Polska. Six facies are identified: F1 – Black mudstone (Menilite shale); F2 – Chert; F3 – Stratified marls; F4 – Sandy–pebbly marls; F5 – Marly-mudstone heterolithics; and F6 – Stratified and laminated sandstone. The facies are grouped into three facies associations that confirm deposition of the Dynów Marls in shallow-water rather than deepwater environments. Interpretation of the facies and their associations suggests conditions typical of a shallow lake or fresh to brackish shelf that was significantly influenced by tides and wave action. In addition to carbonate deposition, siliceous material was supplied by terrestrial rivers but partly produced in situ. Periodic tsunami-type events also occurred and can be traced over considerable distances. Section A at Gorlice provides clear evidence of a facies succession characteristic of deposition in shallow water. These facies exhibit cyclic repetitions that reflect fluctuations in relative sea level, i.e., in the depth of the shallow-water sedimentary basin. This interpretation is supported by the presence of tidal rhythmites, attributed to spring-neap tidal cycles. Moreover, the succession of facies across the Menilite Beds profile indicates both fluctuations in basin depth and a progressive deepening of the shallow shelf. A shallow deltaic system (Magdalena Sandstone), located above the Dynów Marls, has also been documented in this area. The proposed shallow-water interpretation of the study strata does not preclude the existence of deep-water deposits elsewhere in the Paratethys sedimentary basin during the Lower Oligocene. The evidence for tides in the studied lacustrine or shelf succession sections likely reflects the basin’s connection to the open ocean in this area. The discovery and documentation of these shallow-water features mark an important advancement in understanding the paleoenvironmental evolution of the Carpathians. It also contributes significantly to knowledge of the depositional conditions of the Menilite Beds. The results support and refine previous interpretations and paleogeographic reconstructions.