Tertiary strata of the Texas Gulf Coast comprise a number of terrigenous depositional wedges, some of which thicken abruptly at their downdip ends as a result of contemporaneous movement of growth faults and underlying salt.

Barrier islands along the Texas Coastal Zone are part of a complex and dynamic system represented by many distinct yet interrelated environments affected by a variety of resources, natural processes, climatic conditions, and human activities.

The Washita Group in North-Central Texas and southeastern Oklahoma consists of up to 114 m of intercalated shale, limestone, and sandstone that accumulated in the shallow, epicontinental sea of the East Texas Basin.