1. Stratigraphic sections of middle Jurassic San Rafael Group and related rocks from Slick Rock to Uravan in southwestern Colorado Yale Public content 1989. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; For sale by Map Distribution. English. Public. Colorado, Montrose County, and San Miguel County. Jurassic.