Valley and Ridge Province
If you look closely between here and Clinch Mountain, you may notice that the landscape looks "rippled," as if the ridges and valleys in this part of the mountains run parallel to each other. This characterization would actually be correct: you are looking across the Ridge and Valley Province, a region within the Appalachians characterized by alternating series of parallel, linear valleys and ridges. This region, in fact, runs the length of the Appalachians from Alabama all the way to New York.
Why would this part of the mountains look this way? After all, the rest of the Appalachians often appears as a series of jumbled mountains, much less parallel, alternating ridges. Answering this question actually requires going nearly 300 million years into the past. During this time period, what we know as the North American continent and African continent were colliding, creating the ancient supercontinent of Pangaea. As you can imagine, this collision produced an amazing amount of force. This force, in fact, is what is responsible for the high elevations of the Blue Ridge and Great Smoky Mountains to the east of High Knob. In that part of the Appalachians, rocks were superheated and transformed by this intense pressure into "metamorphic" rocks, which were then uplifted to incredible heights.
Far Southwest Virginia was located farther from this collision, however, and here its results were different. Specifically, "sedimentary" rocks - rocks like sandstone and limestone laid down millions of years earlier in ancient seas - were pushed together and folded by the pressure of continental collisions. Some rocks folded upward, while others were folded downward, creating an alternating series of ridges and valleys that we see from High Knob today. Even after this "fold belt" was created, erosion continued sculpting the landscape we see today. Rocks like limestone, which are porous and easily dissolved when exposed to rainwater, easily eroded away in valleys, while more resistant sandstone remained atop the crests of our higher ridges.
The result of this complex and fascinating geologic history is what we see from the High Knob Tower today. Specifically, three ridges - Copper Ridge, Mocassin Ridge, and Clinch Mountain, respectively - can all be seen running parallel to each other as you move farther away from the Knob. In between each ridge are parallel valleys which steer the path of the Clinch River, Copper Creek, and Moccasin Creek, once again in that order as you move from the Knob towards the Tricities. Caves and sinkholes are common in many of these valleys as limestone outcrops and dissolves on each valley's floor.
Clinch Mountain is the highest of these ridges (as can easily be seen from the Knob), and beyond it lies the Great Valley. This valley runs in the same direction as other valleys in the Valley and Ridge but is much, much larger, reaching widths of up to 20-30 miles across in places! Beyond the Great Valley lies the dense, crumpled mass of the Blue Ridge. Like the Valley and Ridge itself, the Great Valley runs the length of the Appalachians from southwest to northeast and formed a major travel artery for Native Americans and even prehistoric mammals such as mastodons and mammoths thousands of years ago. This importance holds even today: I-81 runs much of the Valley's length on its way north, taking advantage of its relatively flat landscape to link our region to New England much farther north.