Folio, (21 ¼ x 18 ¼). (First signature coming loose). 27 chromolithographed maps (2 are double-page). Original brown publisher’s cloth, lettered in gilt (hinge starting, slightly shaken).
First edition. Accompanied the monograph by Samuel Franklin Emmons (1841-1911), the head geologist in charge of the Colorado division of the United States Geological Survey. Emmons is also known for exposing the infamous hoax of the diamond fields in Colorado in 1872. The maps and geological cross-sections depict the topography and geology of Aspen, Tourtelotte, Hunter Park, Lenado, Aspen Mountain, and Smuggler Mountain. Includes the Aspen Special Sheet that shows the town and nearby mines.