It preserves fossils dating back to the Paleogene period.

[2] The Winona formation is a medium to fine grain poorly sorted sand that contains silt, clay, and fossils.

[2] Fossils, molds, and casts are commonly found in lithified beds,[2] and the fossil assemblage includes bivalves, gastropods, echinoids, shark teeth, crabs, foraminifera, and ostracods.

[1] The depositional environment for this formation is considered a shallow-water, near shore marine shelf facies as part of a marine transgression series.

This article about a specific stratigraphic formation in Mississippi is a stub.