Final answer:
Soil grain sizes range from largest to smallest as gravel, sand, silt, and clay. Sedimentary rocks' classification and transport and deposition history can be inferred from grain size distribution. The method for grain size analysis often involves sieving and weighing sediment samples.
Step-by-step explanation:
The soil grain sizes, when ordered from largest to smallest, are typically categorized as follows: gravel, sand, silt, and clay. In a geological context, the process of determining the distribution of these sizes involves several steps such as sieving and weighing sediment samples, with finer grains requiring wet-sieving. The sediment composition can reveal details about the source and environment of deposition, ranging from coarse-grained sand to very fine silt interlaced with clay. This variation in grain size affects both the sediment's transport dynamics and the types of geological impressions, such as ichnofacies, that can be preserved within different grain sizes. Sedimentary rocks are often classified based on their dominant grain size, which also bears insights into their formation and history.