HC, the big rock is called Boar's Tusk. It sits north of Rock Springs about 20 miles, and is apparently considered a "volcanic neck" (at least if your geologic knowledge is limited solely to the internet, like mine). Just like your modern day trips to Idaho, the wagon trains used to use it as a landmark when passing through the Red Desert. Here are a couple of my favorite pictures of it (I didn't take them):


The Kilpecker dunes sit to the north and east a few miles, and it is the largest active dune field in North America and apparently the second largest active field in the world. The actual dunes are a lot more vast than they appear in the videos, since many of them have sage growing up through them but are still sand dunes underneath. In terms of cattle, you'd be amazed at how productive these desert lands can be. Ranchers have run cows out here for a hundred years or more, and I have friends and family who still do today in this exact area. It never ceases to amaze me that you can fly over several miles of nothing but sand, and then see a water hole sitting right in the middle of the dunes. Lots of natural springs in this area.
The dunes are an ever-changing wonder, and they continue to move and evolve out across the desert with each passing year.

