The recently undertaken researches on diverse groups of fossils from the world-famous: Korytnica Clays and associated deposits oil the Korytnica Basin (Middle Miocene; Badenian), southern slopes of the Holy Cross Mountains, Central Poland, extend the range of recognition of organic communities, and their synecological relationships and dependence upon environmental conditions of the Basin. Reviewed and/or commented are all the recent reports, and announced are new investigations on such animal groups as anthozoans (octocorals, regenerated scleractinians), "attached" and free-living bryozoans, some inarticulate brachiopods, creusioid cirripedes, some mollusks (chitons, slipper-limpet gastropods Crepidula, cuttlefish), and fish otoliths. Environmental conditions are discussed in regard with the occurrence of some aberrant pelecypods (Gastrochaena, Stirpulina). Synecological relationships are demonstrated by the epibionts (hydroids Hydractinia, spionid polychaetes, ctenostome boring bryozoans) commensal to the hermit crabs. Indicated are also the taxa significant for tropical and/or subtropical climatic conditions, and for lndo-Pacific bioprovince affinities.