Geologic units in Tyler county, Texas

Willis Formation (Pliocene) at surface, covers 32 % of this area

Willis Formation

Fleming Formation (Miocene) at surface, covers 23 % of this area

Fleming Formation

Lissie Formation (Quaternary; Middle Pleistocene) at surface, covers 21 % of this area

Lissie Formation

Alluvium (Holocene) at surface, covers 10 % of this area

Alluvium

Catahoula Formation (Oligocene) at surface, covers 7 % of this area

Catahoula Formation

Deweyville Formation (Quaternary; Pleistocene and Holocene?) at surface, covers 3 % of this area

Deweyville Formation

Whitsett Formation (Oligocene and Eocene) at surface, covers 2 % of this area

Whitsett Formation

Terrace deposits (Pleistocene and Holocene) at surface, covers 0.9 % of this area

Terrace deposits

Beaumont Formation, areas predominantly sand (Quaternary; Late Pleistocene) at surface, covers 0.5 % of this area

Beaumont Formation, areas predominantly sand

Manning Formation (Eocene) at surface, covers 0.2 % of this area

Manning Formation