Prepared in conjunction with the 2012 GSA Cordilleran Section Meeting, Querétaro, Mexico, this volume's eight field guides showcase three aspects of the geology of the southern end of the North America cordillera: Mid-Tertiary and Quaternary volcanology, environmental geology, and Mesozoic tectonics. Field Guide 25 explores the Cenozoic stratigraphy of Sierra de Guanajuato, one of the most important Mexican mining districts, and addresses a controversial topic, the accretion of the Guerrero terrane and its possible role in the Late Cretaceous—Early Tertiary orogeny. Three guides related to the Trans-Mexican Volcanic Belt, an active magmatic arc related to subduction of the Rivera and Cocos plates, include new data about the recent volcanic history, physical volcanology, and volcanic hazards in Mexico's most densely populated area. Bringing the geosciences into societal problems, one guide presents data on ground deformation related to water extraction in urbanized areas of the Mexico City basin, and another explores the ghost town of the Mineral de Pozos mining district and the effect of mine tailings on groundwater.