Figure 29 - Seismic time-structure map of Lower Cretaceous horizon near the Mexican border showing offset collapse edge (outlined in Figure 30 below) along the trend  of basement faults (purple) that offset the base of the Louann. Northwest-trending anticline represents reactivation of the fault system during Laramide compression related to the Coahuila foldbelt in northeastern Mexico.

Figure 30 -- Pre-Louann basement structure in the same area as Figure 29 (above) showing basement faults (purple).