The Weches Formation is a greensand, slay, and shale geologic formation in Louisiana and Eastern Texas.

[1][2] It preserves fossils dating back to the Paleogene period, specifically the Eocene.

The Weches Formation is a fossiliferous glauconite rich sand that graduates into a clay.

[2] It is considered one of the principal iron bearing beds in Eastern Texas, and is mined for sand in gravel in parts of Texas where exposed.

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