Summer Coon Volcano
Summer Coon Mountain is an eroded Oligocene-aged stratovolcano located in the eastern San Juan Mountains of Colorado, on the western edge of the San Luis Valley. The central intrusive conduit of the volcano are located in Saguache County, 6-1/2 miles north of Del Norte, Colorado. The volcano has well developed radial dikes, but no ring dikes.
(Map from Wohletz, Kenneth, and Grant Heiken. Volcanology and Geothermal Energy. Berkeley: University of California Press, 1992. http://ark.cdlib.org/ark:/13030/ft6v19p151/