In the arenaceous facies of the middle Keuper (Triassic) Roseaux sandstone formation (Moselle, France) channel sandstones occur above obliquely cross-bedded sandstones. A rhythmic succession is observed in which the initial unit is a breccia derived from erosion of older units. The erosion scars can be recognized almost solely by the presence of the breccias, but the extent of reworking can be determined by granulometric and clay mineral studies. Rhaetian (upper Triassic) sandstones are clearly distinguishable on the basis of their clay minerals. On the other hand, broad analogies can be recognized between the Roseaux sandstone, the sandstones of the Lettenkohle formation, and the paralic-type Swiss molasse deposits.