A study of a bar on the Brazos River in Texas found that the sediment is made up of a mix of pebble gravel and sand, with distinct layers of different sizes. The size distributions of the sediment remain consistent across the bar, with two common proportions: either no gravel or about 60% gravel. The sediment types on the bar are arranged in a specific order, with the coarsest at the bottom. By analyzing grain size parameters, the researchers identified that sediments with normal curves are unimodal, while those with non-normal curves are bimodal. Changes in the proportions of each mode lead to systematic changes in properties like mean size and skewness. The researchers also discovered rhythmic pulsations in kurtosis values, which are indicative of two-generation sediments.