Catalina conclusively exhibits evidence for extension in the Miocene. Normal faulting, dikes, and sills, associated with extension, have been correlated to have occured during the emplacement of the Catalina pluton. Locally observed extension and intrusion may be products of larger regional extension, which is similar to other crustal extension forming basins in the southern California region. These basins, located throughout southern California, have been the site of large mineral explorations. Catalina extension maybe further correlated with crustal extension observed in the Colorado River area that has exposed large blocks of Orocopia Schist and its' related units. Tertiary extension has produced major disruption of Mesozoic tectonic and metamorphic features. This requires that Tertiary extension be removed from these older features before they can be interrelated.