The Mermill series consists of very deep, very poorly drained soils on lake plains and till plains. They formed in loamy glaciolacustrine or water-sorted material 20 to 40 inches thick and in the underlying till.
Permeability is moderate in the loamy material and slow or very slow in the underlying till.
Slope ranges from 0 to 2 percent. Mermill loam on a slope of less than 1 percent in a cultivated field at an elevation of 749 feet above m.s.l. 41 degrees 07 minutes 41.8 seconds N., and long. 83 degrees 45 minutes 25.9 seconds W., NAD 27. Thickness of the solum is typically from 24 to 60 inches.