Cross bedded sand deposits of the early Triassic Buntsandstein, an important series of clastic sediments deposited over large parts of west and middle Europe. This example at the Chateau du Haut Barr, in the French Vosges, actual width is 4 meters. Cross bedding is a common structural feature in clastic sediments, indicating that the sands have been deposited in shallow water, with changing flow directions, like a riverbed or the seashore. The clasts deposited may range from fine to coarse fractions (silt, sand, pebbles) and the variations in grain size accentuate the bedding. Cross stratification on a larger scale is evidence of deeper marine deposits or windblown sands (dunes). When reconstructing ancient depositional environments, geologists analyze cross bedding to establish the prevailing wind or flow directions of the period studied