to hornfels and quartzite. Stratigraphically below the Leadville, the chert bearing Devonian Dyer Dolomite Member of the Chaffee Formation was altered by the metamorphism to impure silica-rich marble and occasional serpentine-bearing marble. The Yule Marble is a metamorphic facies of the regionally distributed Leadville Limestone of Mississippian age deposited 350 million to 324 million years ago. The Leadville within the Yule area was transformed by contact metamorphism that occurred during the latest Eocene and Oligocene epochs (34 to 28 million years ago) associated with the intrusion and uplift of the nearby granitic Treasure Mountain Dome. The uplift of the Treasure Mountain Dome tilted the limestone away from the intrusion resulting in the marble bed dipping at an angle into the mountain. The marble unit along with older and younger adjacent units in the Yule Valley have a north-northwest strike paralleling the valley and variable dips of 35 to 50 degrees to the west-southwest. This local contact with the heat and pressure from the intrusion of hot granitic magma recrystallized the Leadville Limestone into a distinctive white marble. Although the Leadville Limestone covered hundreds of square miles and was the ore host at the Leadville mining district, the Yule Creek Valley is the only known location of marble in the region. When the magma cooled, it crystallized into granite. This local geological activity resulted in a type of marble that is 99.5% pure calcite, with trace amounts of non-calcite inclusions (mainly quartz), and has a density of . The non-calcite inclusions were caused through penetrations along the seams created by the dome uplift rather than through metamorphic contact with the uplifted dome. Though marble is on both sides of the creek, the only visible marble is the seam of the present-day quarry on the west side of Yule Creek. Timeline Development of Yule Marble is put into context with Colorado geology by showing the passage of time from earliest rock units to the present with "Ga" = billions of years ago and "Ma" = millions of years ago. Characteristics It is the grain of Yule Marble that gives an appearance of smooth texture, a homogeneous look, and a luminous surface that polishes well. These qualities are why it has been chosen for a number of major national and state landmarks, most notably the Lincoln Memorial. Because of its aesthetic value, architect Henry Bacon successfully urged that it be used to clad