OF-15-12 Geologic Map of the Piney Creek Quadrangle, Arapahoe, Douglas, and Elbert Counties, Colorado Download Publication Details The purpose of this CGS map is to describe the geology, geologic resources and geologic hazards of this 7.5-minute quadrangle located southeast of Denver. The quadrangle covers an urban area that includes the towns of Centennial, Aurora, and Parker, as well as the Aurora Reservoir. Much of the area mapped consists of two Eocene-to-Upper-Cretaceous (Denver Basin) bedrock formations: the most predominant is the Dawson Arkose along with minor amounts of the Denver Formation. Drainages are covered by Quaternary alluvial deposits. CGS staff geologist Matthew L. Morgan completed field work on this project during the summer and fall of 2014. 2 plates: geologic map, along with 3-D oblique view, and cross section; also included is GIS data. Digital ZIP download. OF-15-12D Citations Morgan, Matthew L. “OF-15-12 Geologic Map of the Piney Creek Quadrangle, Arapahoe, Douglas, and Elbert Counties, Colorado.” Geologic. Open File Reports. Golden, CO: Colorado Geological Survey, 2015. https://coloradogeologicalsurvey.org/publications/geologic-map-piney-creek-quadrangle-arapahoe-douglas-elbert-colorado.