Cross-stratification is a sedimentary structure that occurs from migrating ripple (smaller-scale) or dune (larger-scale) laminae and bedforms due to current flow processes in various environments, such as fluvial, eolian, lacustrine, or marine. Sedimentation causes an inclined foreset in which mobile grains are carried over the stoss and ultimately deposited onto the lee side where it migrates with the horizontally deposited bottomset, as seen by the red annotations. This results in the truncation of sedimentary layers, known as cross stratification. These structures can also be indicative of direction of paleoflow in that currents flow from stoss to lee. However, an interpretation of paleoflow is best exemplified in samples such as this which show unidirectional flow direction, indicated by the arrow. Cross beds are distinguished from each other by the shape of their bounding surfaces. When the bounding surfaces appear to be planar and 2-dimensional, the bed is a tabular cross-bed. Meanwhile, if the bounding surfaces appear to be curved and dimensional, it is called a trough cross bed. The upper annotated portion of this sample is an example of well-defined tabular cross-bedding.