A breccia of rounded crinoidal limestone clasts cemented by two generations of stromatolites, then by radiaxial cement with remaining voids filled by marine sediments i.e. crinoidal detritus, micrite with bivalve shells or micrite with Pokornyopsis ostracods was found at Horne Sŕnie quarries near Trencin. This breccia, which can be assigned to the Krasin Breccia Member (Middle to Upper Jurassic of Czorsztyn Unit), bears several signs of freshwater influence. Isotopic data from the first stromatolite generation display a negative δ¹³C, the clasts in the breccia are rounded and some dissolutional effects have been observed in the voids. The final filling of the cavities with crinoidal detritus and later with filament microfacies suggests that the breccia was formed in the time of the transition between Bathonian and Callovian. It is the first evidence of freshwater diagenesis in the Pieniny Klippen Belt.