Geologic units in Montgomery county, Texas

Willis Formation (Pliocene) at surface, covers 49 % of this area

Willis Formation

Lissie Formation (Quaternary; Middle Pleistocene) at surface, covers 24 % of this area

Lissie Formation

Fleming Formation (Miocene) at surface, covers 13 % of this area

Fleming Formation

Alluvium (Holocene) at surface, covers 6 % of this area

Alluvium

Beaumont Formation, areas predominantly sand (Quaternary; Late Pleistocene) at surface, covers 5 % of this area

Beaumont Formation, areas predominantly sand

Deweyville Formation (Quaternary; Pleistocene and Holocene?) at surface, covers 2 % of this area

Deweyville Formation

Terrace deposits (Pleistocene and Holocene) at surface, covers 0.8 % of this area

Terrace deposits