Recent studies have demonstrated the amount of vertical hydrologic confinement between two karst hydrogeologic units in the Cretaceous Trinity geologic units of central Texas. The hydrogeologic units being studied are the Lower Glen Rose limestone, the Hensel formation, and the underlying Cow Creek limestone which are part of the Middle Trinity Aquifer. Within the study area, the Lower Glen Rose limestone receives recharge through numerous fractures, sinkholes, and caves. Most of the recharge to the Cow Creek comes from lateral flow within the Cow Creek Limestone which is the principal hydrogeologic unit of the Middle Trinity Aquifer. Overlying the Cow Creek limestone is the Hensel formation which, in the study area, consists mostly of dolomite and serves as a confining unit. Confinement by the Hensel is reduced where vertical fractures cut through the Hensel. Jacob’s Well Spring is formed along one of these fractures and is a significant conduit/cave system that drains the Cow Creek limestone over much of the study area. Two multilevel wells were installed upgradient of Jacob’s Well Spring and cross gradient to the conduit/cave system. One of these wells (JWNA) is a dual completion well with two monitoring zones and the other (Coleman’s Canyon) is a multiport well with 10 monitoring zones. Differences in water levels between the Lower Glen Rose and the Cow Creek indicate that there is hydrologic separation between these two units and that the Hensel formation provides that separation.