Geologic units in Shelby county, Texas

Wilcox Group, undivided (Paleocene to Eocene) at surface, covers 78 % of this area

Wilcox Group, undivided

Alluvium (Holocene) at surface, covers 11 % of this area

Alluvium

Carizzo Sand (Eocene) at surface, covers 7 % of this area

Carizzo Sand

Terrace deposits (Pleistocene and Holocene) at surface, covers 3 % of this area

Terrace deposits

Reklaw Formation (Eocene) at surface, covers 1 % of this area

Reklaw Formation

Queen City Sand (Eocene) at surface, covers 0.7 % of this area

Queen City Sand

Weches Formation (Eocene) at surface, covers 0.1 % of this area

Weches Formation

Sparta Sand (Eocene) at surface, covers < 0.1 % of this area

Sparta Sand