 You can't really see forever from this vantage on Beaver Rim southeast of Lander, but you can see a lot of Wyoming's geologic history. On the northwest is the spectacular Wind River Range, which was uplifted to become part of North America's backbone about 50 million years ago. It's hard to visualize now, but after this mountain range was pushed up more than three vertical miles, the valley between the mountains were filled, almost to the brim with sediments and materials ejected from volcanoes in the Absorca Range. The soft tan standstone that forms the cap rock I'm standing on is relatively young. Most of the light-colored rock exposed below this point is a soft fossil-rich mixture of silt and volcanic debris that extends from here east into Nebraska and South Dakota. Wherever it appears, this white river formation erodes into fantastic shapes like the hoodoos found along the Beaver Rim. A little over five million years ago, the deposition and field cycle ended and a period of massive and rapid erosion started. The Wind River cut down through and carried away thousands of feet of sediment, carrying them to the east where they helped build the Great Plains and formed the basins that we're looking at today. The Beaver Rim is an 80 mile long scarf on the south end of the basin, which is retreating as the Wind River relentlessly gnaws away at it. So, from this spot, you can see the results of major episodes of mountain building, deposition, and erosion, all essential to understanding Wyoming. From the University of Wyoming Cooperative Extension Service, I'm Rachel Miller, Exploring the Nature of Wyoming.