Figure 1–4. Color as an indicator of drainage. The soil on the left is the Cecil series, a well-drained mineral soil typical of the NC piedmont. The soil on the right is the Coxville series, a poorly drained mineral soil found in the NC coastal plain.
side-by-side image of Cecil series and Coxville series soils

John A. Kelley, USDA-NRCS, Flickr  CC BY 2.0