1. Colorado, Mt. Jackson quadrangle Yale Public content 1911. 2011-05-17T19:20:44Z. 2015-10-21T14:59:22Z. Geological Survey (U.S.). The Survey. English. Public. Chaffee County (Colo.), Eagle County (Colo.), Gunnison County (Colo.), Lake County (Colo.), and Pitkin County (Colo.).