Abstract Although the southern Front Range in Colorado Springs and Manitou Springs contains a near-complete record of Rocky Mountains geological evolution from Proterozoic to Present, there nevertheless are persistent geological problems that have eluded understanding for as much as 125 years. In keeping with the 2013 GSA Annual Meeting theme, “Celebrating Advances in Geoscience,” this field trip visits long-known elements of Front Range geology that merit reexamination within the context of new paleoenvironmental and geochronology data. Of note are: (1) the Great Unconformity and its chemically weathered substrate that correspond to a time of profound changes in global ocean chemistry; (2) lower Paleozoic strata that record sea-level fluctuations, attributable in part to regional tectonism; (3) an array of granite-hosted sandstone dikes, for which a new emplacement model is proposed; and (4) the Front Range monocline at Garden of the Gods Park, examined from the standpoint of its temporal evolution, newly bracketed by results of 40 Ar/ 39 Ar age analysis of illite generated by shear upon bedding-parallel faults.