Abstract: Study of the vertical succeeding type of the rhythmic sequences such as flysch deposits can offer interesting informations concerning the generating processes and the depositional areas. Statistical analysis,such as Markov chains analyses,can establish if the different lithologies ver-tical association is random or not and,if not,which is the sedimentary sequences preferential order. This type of analysis was applied to the flysch deposits from the Lower Tarcau Sandstone Formation(East Carpathian Mountains,Romania),which were observed on the presence of a generating process with a memory and thus these deposits,at least for the studied interval,are the products of turbiditic processes accumulated in a sedimentary area with good zonation of de-positional subenvironments such as channeled middle deep-sea fan.