It commonly is gravelly loamy coarse sand but includes strata of gravel and sand. Content of rock fragments ranges from 15 to 35 percent. Sand content ranges from 75 to 95 percent. Gravel content ranges from 15 to 75 precent, but averages less than 35 percent. Some pedons contain cobbles and stones.
Reaction ranges from slightly acid to moderately alkaline.
These are the Biscay , Marshan , Niwot , and Will series. These soils do not have a paralithic contact within a depth of 60 inches. The Mudhen soils are on nearly level or depressional parts of strath terraces. Slope ranges from 0 to 2 percent. These soils formed in 40 to 60 inches of loamy outwash and in the underlying calcareous gravel and sand.