Reaction is strongly to slightly acid in the upper part and medium acid to neutral in the lower part. The R layer is hard fractured limestone bedrock that is tilted less than 20 degrees from horizontal. These are Caspiana , Catoosa , Dardanelle , Deepwater , Mason , Mer Rouge , and Tiptonville series in the same family. Soils in similar families are Armistead , Ashwood , Benklin , Claremore , Clareson , Fitzhugh , Newtonia , Nowata , Okay , and Reelfoot series. Armistead, Benklin, and Reelfoot soils have wetness mottles within 16 inches of the surface.
Ashwood soils have a fine control section.
Caspiana, Deepwater, Mason Mer Rouge, Newtonia, and Tiptonville soils have a solum more than 60 inches thick. Catoosa, Claremore, and Clareson soils have a solum less than 40 inches thick. In addition, Clareson soils have a clayey-skeletal control section. Dardanelle soils do not have bedrock within 60 inches of the surface. Fitzhugh and Okay soils have a fine-loamy control section.