👉 Mudstone is a type of sedimentary rock that forms from the accumulation and cementation of clay-like materials in a river or stream. It is commonly found in areas with high levels of rainfall, where there are often times periods of rapid erosion and deposition. Mudstones can vary in texture, color, and composition, but they generally contain particles ranging from small grains to larger silt and sand. They are primarily composed of clay minerals such as calcite or dolomite, which have been altered