Sedimentary structures are features formed in sedimentary rocks during or shortly after the deposition of sediments. They provide important clues about the environment in which the sediments were deposited, such as rivers, lakes, or oceans. Common types of sedimentary structures include bedding, cross-bedding, and ripples, each indicating different processes like water flow or wind action. These structures can also reveal information about the geological history of an area. For example, the presence of fossils within sedimentary layers can indicate past life forms and environmental conditions. Understanding these structures helps geologists interpret Earth's past and predict future geological changes.