Cross Stratification

When ripples move over the sediment surface, and have time and space to deposit sediment, their passage is recorded by the development of cross stratification. As the ripple advances downstream, sand grains roll up the upstream side and collect on the ripple crest. When too many grains accumulate, they avalanche down the downstream face of the ripple. This motion produces a sediment layer that is oriented at an angle to the sediment bed. The resultant deposit is said to be cross stratified.