Medicine Bow Mountains
The Medicine Bow Mountains are the middle prong of the Front Range that projects into Wyoming, and the northward extension of the Never Summer Range in Colorado. This mountain range is separated from the Laramie Mountains by the Laramie Basin, a structural basin underlying the Laramie plains. The mountains are characterized by a rather broad, rolling upland surface approximately 9,000 feet above sea level, above which rise two areas of higher relief. The highest part of the Medicine Bow Mountains, the Snowy Range, consists of a thick sequence of metasedimentary rocks, including a thick, very resistant white quartzite that culminates in Medicine Bow Peak at 12,006 feet.
The Medicine Bow uplift contains an excellent geologic record of two major ages of Precambrian rocks in the western United States: the older Archean (more than 2.5 billion years old) and the younger Proterozoic (2.5 billion to 540 million years old). A thick series of Proterozoic metasedimentary rocks is in fault contact along a major shear zone (or suture) with an older sequence of Archean-age metamorphic rocks. Stromatolites occur within 1.7 billon-year-old metasedimentary rocks. Stromatolites are fossil remains of blue-green algae, among the oldest and earliest forms of life known. They resemble giant cabbage heads and can be seen along the road to Lewis Lake en route to the Sugarloaf Recreation Area.