The Upper Triassic carbonates of the Krizna Unit in the eastern part of the Krivánska Malá Fatra Mts contain the unique siliciclastic interbeds. They are developed between the Ramsau Dolomite Formation and the Hauptdolomite Formation, and comprise alternating dark grey shales and pale grey dolomites. Such a shaly-dolomite formation is unknown from the Upper Triassic formations of the Krížna Unit, which makes it possible to define a new lithostratigraphic unit (Trzinovo Formation). The Ramsau Dolomites beneath the Trzinovo Formation contain microfauna of Carnian foraminifers. Therefore, the Carnian age has also been constrained for the Tržinovo Formation, which by the reduced carbonate productivity and enhanced terrigenous influx could be related to the Reingraben Event. This event related to the “Carnian Pluvial Episode” is also inferred in the Tržinovo Formation by the presence of lingulide brachiopods (Lingularia) and spinicaudatan crustaceans (Euestheria). This fauna provides evidence of not fully marine conditions of the Tržinovo Formation, influenced by continental freshwater influx and humid climate.