Geologic units in Holmes county, Mississippi

Cockfield (Eocene) at surface, covers 40 % of this area

(Claiborne group), Irregularly bedded, more or less laminated liginitic clay, sand, and lignite; sparingly glauconitic.

Alluvium (Holocene) at surface, covers 27 % of this area

Loam, sand, gravel, and clay; mapped only in Mississippi River Alluvial Plain.

Cook Mountain formation (Eocene) at surface, covers 15 % of this area

(Claiborne group), Southeast of Pearl River, marl, limestone, glauconitic sand, and chocolate-colored clay; northwest of Pearl River, predominantly chocolate-colored clay with some glauconitic sand.

Kosciusko formation (Eocene) at surface, covers 11 % of this area

(Claiborne group), Irregularly bedded sand, clay, and some quartzite.

Jackson group (Eocene) at surface, covers 4 % of this area

Yazoo clay, green and gray calcareous clay containing some sand and marl; Moodys Branch formation at base, shells embedded in glauconitic clayey quartz sand.

Zilpha formation and Winona formation (Eocene) at surface, covers 1 % of this area

(Claiborne group), Zilpha clay, chocolate-colored clay containing some glauconitic sand, not recognized north of Yalobusha River; Winona sand, highly glauconitic sand, more or less clayey.