Irwin, Lubbock, and Tully soils have mixed minerology. In addition, Irwin and Lubbock soils formed in old alluvial sediments, and Tully soils formed in residuum from interbedded clayey shale. Wymore soils have a wetter climate, contain more mottles in the lower part of the solum and have thinner mollic epipedons. Crete soils are on nearly level to strongly sloping loess covered uplands and stream terraces. Slope gradients are 0 to 1 percent in the western part of the series range, and range from 0 to 11 percent in the eastern part of the series range.
Slopes are typically convex.
The mean annual temperature ranges from 50 to 55 degrees F, and the mean annual precipitation ranges from 22 to 34 inches. These are the Butler , Fillmore , Hall , Hastings , Holdrege , and Wymore soils. Butler soils are on flat or slightly concave uplands and have an abrupt boundary between the A and B horizon. Fillmore soils have an albic horizon, are somewhat poorly drained and are in depressions. Hall soils are fine-silty and are on nearly level to gently sloping terraces and uplands.