Pine Mountain
On a clear day, it is possible to see a long, linear ridge running the horizon from this view to the north from the Knob. This ridge, Pine Mountain, is a nearly continuous sandstone ridge that is 125 miles long and forms much of the Virginia and Kentucky state line. This ridge is so dominant that the location of communities and roads even reflects the existence of Pine Mountain: minimal road crossings provide passage across the ridge, and water itself has found gaps through the mountain at only a handful of locations, two of the closest being at Pineville, Kentucky and at the famous Breaks Interstate Park near Haysi, Virginia.
Pine Mountain is obviously a unique feature of our region, which begs the question of how it originally formed. Pine Mountain is actually a thrust fault, or a rip in the top part of Earth’s crust where one set of rock layers has been forced on top of and over another series of rocks. Pine Mountain forms just the northern and western lip of these thrusted rock layers, which are really thousands of feet thick and extend mostly belowground into Virginia and Tennessee. You can even see this structure today at places like Pound Gap along U.S. Highway 23 (where angled rock layers have been exposed) and even at overlooks along the scenic Pine Mountain Trail (which occur mostly at rocks angled sharply in the direction of the thrust fault). This "block" of thrust-faulted rocks, the Cumberland Mountain Overthrust Block, is really a massive, rectangular mass of rock that underlies much of Southwest Virginia in the vicinity of High Knob.
The force needed to reposition rocks in this way clearly needed to be huge, and such an impact occurred around 300-275 million years ago, when the North American continent collided with Africa and Europe. This collision formed the modern-day Appalachian Mountains and, along with them, forced the rocks in the High Knob vicinity several miles to the north and west, creating the thrust fault forming Pine Mountain. The thrust fault isn't just a dramatic ridge, though. Major cliff lines all along the mountain's ragged lip create very unique habitats for species adapted to vertical lives. One of these species, the Green Salamander, is especially unique because it is a climbing species of salamander and actually uses the steep, moist cliff faces as its home. This salamander and other cliff-dwelling species are considered at-risk by many conservation agencies since cliff habitats and the forests surrounding them have been altered by humans all across Appalachia. On Pine Mountain, though, the same rugged landscape that prevents ease of human movements actually helps these creatures, since steep slopes and sheer cliffs form protected refuges along the mountain's spine.