The lower Tertiary of the Texas Gulf Coast
The lower Tertiary section in the western Gulf Coast is most complete and best exposed in the bluffs of the Brazes River Valley (Figs. 1 and 2), and has received the most study of any area in the state. The low rolling hills of this region provide limited outcrops, so most good exposures are confined to high banks along the Brazes River. Strata dip toward the Gulf of Mexico at uniformly low dips, and exposures gradually shift upsection as one travels downriver. The regular progression upsection continues to the area of Navasota and Hempstead, where Quaternary sediments of the flat-lying coastal plain lap onto the youngest (Miocene age) of the more steeply dipping Tertiary formations. The Brazes Valley was one of the more heavily traveled routes by settlers and explorers, and the Stone City locality (site of the King’s Highway [El Camino Real or Old Spanish Road—OSR] crossing of the Brazes River) was the source of material for the first study of Texas fossils.