1. Geologic map and sections of the Holy Cross quadrangle, Eagle, Lake, Pitkin, and Summit counties, Colorado [cartographic material] Yale Public content 1974. 2013-04-30T18:17:54Z. 2013-05-08T12:07:04Z. Tweto, Ogden, 1912-1983. U.S. Geological Survey. English. Public. Colorado, Eagle County, Lake County, Pitkin County, and Summit County.