Geologic units in New Madrid county, Missouri

Holocene series (Quaternary-Holocene Series) at surface, covers 100 % of this area

Alluvium - clay, silt, sand, and gravel.

Alluvial deposits (Quaternary) at surface, covers 0.2 % of this area

Sand, silt, clay, and gravel. In flood plain of Mississippi River more than 100 feet thick; in smaller streams generally less than 20 feet thick.