Geologic units in Grimes county, Texas

Fleming Formation (Miocene) at surface, covers 25 % of this area

Fleming Formation

Yegua Formation (Middle Eocene) at surface, covers 14 % of this area

Yegua Formation

Willis Formation (Pliocene) at surface, covers 13 % of this area

Willis Formation

Catahoula Formation (Oligocene) at surface, covers 11 % of this area

Catahoula Formation

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

Alluvium

Manning Formation (Eocene) at surface, covers 9 % of this area

Manning Formation

Wellborn Formation (Eocene) at surface, covers 7 % of this area

Wellborn Formation

Cadell Formation (Eocene) at surface, covers 5 % of this area

Cadell Formation

Whitsett Formation (Oligocene and Eocene) at surface, covers 4 % of this area

Whitsett Formation

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

Terrace deposits

Lissie Formation (Quaternary; Middle Pleistocene) at surface, covers < 0.1 % of this area

Lissie Formation

Oakville Sandstone (Miocene) at surface, covers < 0.1 % of this area

Oakville Sandstone