Tertiary system

Pliocene series - Mounds Gravel (Lafayette Formation) - ferruginous, chert gravel, max of 60 ft. Eocene series - Wilcox group - includes Holly Springs Formation - bedded sandstone, clay and gravel, max of 1200 ft.; Ackerman Formation - clay with lens of sand and gravel, max of 100ft. Paleocene series - Midway Group - includes Porters Creek Clay - bentonitic clay, max of 200 ft.; Clayton Formation - marl, fossiliferous, calcareous, limonitic, glauconitic sand and clay, max of 20 ft.
State Missouri
Name Tertiary system
Geologic age Tertiary-Late-Pliocene to Paleocene
Lithologic constituents
Unconsolidated > Coarse-detrital > Sand (Bed, Lens)
Unconsolidated > Fine-detrital > Clay (Bed)
Unconsolidated > Coarse-detrital > Gravel (Bed)
Unconsolidated > Marl (Bed)marl refers to loosley consolidated calcareous clays, silts and sands containing glauconite

Howe, W.B. and Koenig, 1961, The Stratigraphic Succession in Missouri: Missouri Geological Survey and Water Resources, Vol XL. 2nd Series.

NGMDB product
Counties Dunklin - Scott - Stoddard