1. Geology of the Mt. Aetna volcanic center, Chaffee and Gunnison counties, Colorado [cartographic material] Yale Public content 1984. 2002-06-01T04:00:00Z. 2023-09-16T03:01:33Z. Geological Survey (U.S.). The Survey : [Books and Open-File Reports Section, distributor]. English. cartographic image. Public. Colorado, Chaffee County, and Gunnison County.