The soils formed in alluvium from phyllite. The average annual precipitation ranges from 55 to 75 inches. The frost- free season is 150 to 200 days. These are the Cokedale , Mukilteo , Samish , Tokul , and Vanzandt soils and the competing Barneston soils. Mukilteo soils are Histosols.
Samish soils are coarse-silty.
Tokul soils have a duripan at 20 to 40 inches. Vanzandt soils are 20 to 40 inches deep to a paralithic contact with dense glacial till. These soils are subject to rare periods of flooding. Used for pasture and woodland. Native vegetation consists of Douglas-fir, red alder, paper birch, western redcedar bigleaf maple and western hemlock with an understory of vine maple, elderberry, salmonberry, geranium, and rose.