Sedimentary rocks are formed from the accumulation and compression of mineral and organic particles over time. These particles can come from the erosion of existing rocks, the remains of plants and animals, or chemical precipitation. Common types of sedimentary rocks include sandstone, limestone, and shale. These rocks often have distinct layers, known as strata, which can provide valuable information about Earth's history. Sedimentary rocks are typically found in areas like riverbeds, lakes, and oceans, where sediments can settle and build up. They are important for understanding past environments and are often rich in fossils.