The Pre Oreak Cave presents interesting filling deposits that testify its more or less recent evolution. In the first hall, residual strips of a filling that were occupying the entire space up to at least 8 m of height. Of particular interest is the deposit of muds and sands that characterize the second hall. It is a slimy and sandy sequence with a limited clay fraction and a presence of rougher sands only in the superior part. The morphologic composition of the sediment, is characterized by a net prevalence of quartz that overcomes, in many samples the 90%. The calcite is present only in the rough levels of the deposit superior part. The texture characteristics of such deposits induce to think that the sediments essentially come out from the direct Flysch erosion of the Bernadia highland, whilst they do not seem to come from the pedogenized deposits with a good degree of evolution.