Clinch Mountain
It's not all that difficult to pick out Clinch Mountain, a feature that is perhaps the single most visible landscape feature from High Knob. That's because Clinch Mountain is simply massive - not because of its height but its sheer length. Although it seems like Clinch Mountain stretches forever from the view on High Knob, it actually runs around 150 miles in length, from Knox County, Tennessee all the way to Burkes Garden, in Tazewell County, Virginia. Along the way, the ridge has numerous kinks and curves even though it maintains its southwest-to-northeast angle throughout.
Why would Southwest Virginia and Northeast Tennessee have such a long mountain traversing the region? The answer lies in the mountains' infancy, during a time referred to as the Alleghanian Orogeny some 300 million years ago. During this orogeny (or "mountain-building event"), intense pressure from the collision of the African and North American continents folded and uplifted existing rocks across the Appalachian region. Here in Southwest Virginia, rocks like sandstone and limestone - both deposited millions of years earlier, when the region was located beneath a shallow sea - were bent and folded into what geologists call a "fold and thrust belt." To think about how this process works, consider taking a bedsheet, stretching it out tight, and pushing inward on both sides. The parallel, alternating ripples that result are similar to what happened here, in what is called the Valley and Ridge Province of Virginia. Clinch Mountain is formed from one of these bands of mostly sandstone, which has resisted erosion while surrounding deposits of limestone and similar rocks in surrounding valleys eroded away.
Along its entire 150-mile length, there are only two major gaps that are found within Clinch Mountain that allow easy passage from one side of the ridge to the other. These two gaps are known as Big Moccasin Gap and Little Moccasin Gap - both located in Southwest Virginia and viewable from High Knob. Big Moccasin Gap is found in Scott County near the town of Gate City and can (barely) be seen from this vantage point on High Knob (see the placeholder on the previous page). Little Moccasin Gap is found between Abingdon and Hansonville, near the John Douglas Wayside Exhibit on U.S. Highway 19. This gap can be seen just to the right of Brumley Mountain from the High Knob Tower. Both of these gaps are bisected by streams, most famously Big Moccasin Gap for its passage of Moccasin Creek into the Holston River a short distance to the south.
Big Moccasin Gap also has major historical importance. Daniel Boone used the gap as a key feature along the famous Wilderness Road, a route which was once the key path for settlers making their way from the far eastern U.S. to Kentucky. The use of this gap made traveling through the mountains much easier, rather than going up and over the mountains themselves. In fact, this ease of travel is still used today. Rail lines, along with U.S. Highways 23, 58, and 421, all pass through the gap on their way from Southwest Virginia into Tennessee.