|Geologic age||Middle Eocene|
Unconsolidated > Fine-detrital > Clay (Bed)
Unconsolidated > Coarse-detrital > Sand (Bed)
Sedimentary > Coal (Bed)
|Comments||Mainly unconsolidated sand and silty clay/interbedded with carbononaeous clay and lignite. Maximum thickness is 1500 ft. Cyclic marine-nonmarine units formed in a fluvial-deltatic system. Typical delta sequence; Delta Plain:clay and coal, Inner Fringe:sand, Outer Fringe:clay and sand, Pro-Delta:clay, Marine:clay.|
|Stratigraphic units||Cockfield Formation, Cook Mountain Formation, Sparta Sand, Memphis Sand, Cane River Formation, Carrizo Sand.|
Wilbert, L.J. Jr. 1953, The Jacksonian Stage in southeastern Arkansas: Ark. Res. Devel. Comm., Div. Geology Bull. 19, 125 pp.
|Counties||Ashley - Bradley - Calhoun - Cleveland - Columbia - Craighead - Cross - Dallas - Grant - Jefferson - Lafayette - Miller - Nevada - Ouachita - Poinsett - Pulaski - Saint Francis - Saline - Union|