Reaction is slightly alkaline or moderately alkaline and contains carbonates. There are no other series in this family. Competing series may change as they are updated to the 8th Edition of Keys to Soil Taxonomy. The Havana series has not been updated to the 8th Edition of Keys to Soil Taxonomy, but was a competing series to Mermill under previous taxonomic classification. Havana soils typically average less than 27 percent clay in the lower part of the series control section.
Mermill soils are on lake plains, and less commonly on till plains of late Wisconsin age.
They have a plane or concave surface with a slope gradient of 0 to 2 percent. They formed in 20 to 40 inches of loamy glaciolacustrine or water-sorted material and in the underlying till. Elevation ranges from 600 to 800 feet. The frost-free period is 140 to 180 days. These are the Aurand , Haskins , Houcktown , and Rawson soils.