Extensive karst and solution-collapse brecciation (ancient cave systems) developed within these carbonates as a result of meteoric water infiltration during the widespread post-Sauk unconformity (Wilson, 1994). It is these karsted zones that contain significant amounts of porosity and permeability in what are otherwise low-porosity and low-permeability rocks. The high-porosity and -permeability karsted zones can be targets for CO2 sequestration when they subcrop beneath competent seals, such as the ubiquitous Devonian-age Woodford Formation. Main site www.beg.utexas.edu/environqlty/co2seq/co2data.htm