| 1. |  | The Great Hexagon and the 39th Parallel. November 2009 | Surveying; U.S. Coast and Geodetic Survey; Tushar Mountains (Utah); San Juan Mountains (Colo. and N.M.); | Two images of old stone observation stations along the survey of the 39th Parallel line. One photo is of the summit station on Uncompahgre Peak, Colorado. The other is of the summit station on Tushar Mountain,... |