Today, Ugly Mountain has an unremarkable appearance when seen from a distance. It’s nearly 2,600 feet in elevation put it well beneath more spectacular peaks. When seen from above, Today, Ugly Mountain has an unremarkable appearance when seen from a distance. Its near 2,600 feet in elevation put it well beneath more spectacular peaks.
When seen from above, the landform that rests between Sugar Grove and Palo Alto, Virginia, has the shape of a deflated football.
Like all of Pendleton County’s mountains and valleys, Ugly Mountain emerged from a geologically violent past. That said, its specific history sets it apart from nearly any other similar peak in the Appalachians.
Ugly Mountain, like Mole Hill near Harrisonburg, Virginia, or Trimble Knob outside of Monterey, Virginia, started life as a type of volcano less than 45 million years ago. Interestingly, volcanic activity took place well after the mountains themselves formed and reformed over and over again throughout hundreds of millions of years.
All that said, Ugly Mountain has different types of volcanic rocks that indicate potentially more than one different period of magma intrusion.
Four times in the history of Earth, a mountain range rose where the Appalachians dominate the landscape now as Four times in the history of Earth, a mountain range rose where the Appalachians dominate the landscape now as the North American continent on one hand and Africa and Europe on the other, and played “bumper cars” repeatedly for approximately one billion years.
Eastern West Virginia has one of the seven “provinces” of the Appalachian Mountains. The valley and ridge section formed during the last mountain forming period, called the Alleghenian by geologists. The lengthy ridges and valleys create a landscape that differentiates the region from much of the rest of the Appalachians.
The landscape prior to that final period of uplift contained sedimentary rocks, layers of stone that formed gradually over time as sediments deposited to the floor of a shallow sea. These include sandstone, shale and limestone deposits that formed between 540 million and 300 million years ago.
Groundwater percolating through limestone eroded away massive cave systems and also provides the distinctive water used in traditional Bourbon whiskey.
One billion years ago, 500 million years ago, 375 million years ago, and, finally, between 325 and 260 million years ago, continent-bearing plates collided. Each time, the collisions of continents folded and buckled layers of rocks, in some cases pushing chunks of continents into angles and even standing on end. North America separated once again from its on again, off again neighbors 200 million years ago and the Atlantic Ocean has continued to widen ever since.
This created the dramatic formations seen in natural and man-made cuts through the mountains and also the dynamic landscape of eastern West Virginia. At different points in its history, the Appalachians rose at least as high as the mighty modern Himalayas, home of Mount Everest.
Ugly Mountain and Mole Hill stand out geologically from their surroundings because they have vastly different types of rocks within. According to a field guide published by the West Virginia Geological Survey in 2003, volcanic, or “igneous rocks in the vicinity of Pendleton County and Augusta, Highland, and Rockingham counties in Virginia, were first recognized in 1837.”
Experts continued to study the rocks over time to unlock the mystery of their presence in an environment dominated by sedimentary rock. Since then, scientists have returned many times to study the geology of the area.
It found pockets created within the ground by the stretching caused by repeated collisions and pulling apart.
For comparison, the last of the dinosaurs died off about 66 million years ago, likely in the wake of a dramatic asteroid collision with Earth.
Theories for why the magma appeared at that point range from wear and tear on the Earth’s crust from mountain formation to effects from a meteor that crashed into the lower Chesapeake Bay less than 40 million years ago, leaving a 55-mile-wide impact crater still detectable today.
Different types of “intrusions” of magma took place at different times. Large upwellings created Ugly Mountain and Mole Hill, but in other areas, magma filled cracks between layers, called dikes in geology. A Pittsburgh Geological Society publication indicated that these form when magma is “injected into fractured and structurally deformed country rocks.”
These formations dot the region around Sugar Grove, but they also extend eastward into Virginia and as far north as Martinsburg. A 1995 Virginia Minerals article explains that the western edge of these formations starts “13.5 miles west of the Virginia-West Virginia state line” on “US Highway 33.”
One well-known outcropping of such a dike is located near the old Wilfong Church.
Rockhounds also know Sugar Grove as an area rich in zeolites, created in nature when molten rock encounters groundwater. A National Library of Medicine publication describes them as “crystalline . . . microporous, three-dimensional structure” formed by combinations of oxygen, silica, and aluminum. They serve as filters that pull harmful or toxic substances from different substances. Natural and artificial zeolites currently are used for water purification, nuclear waste management, and cat litter. Researchers increasingly look to potential use in medicine, including vaccine delivery and cancer treatments.
Ugly Mountain serves as one of the largest areas of magma concentration in a post mountain building setting. Unlike most volcanic structures, the mountain actually has two distinct volcanic formations that combined into a single mountain structure 8,000 feet long and about 2,000 feet wide at its greatest extent.
Geologists call Ugly Mountain a diatreme and its age gives it, according to experts “the youngest igneous rocks in the Eastern United States.” Magma erodes its way upwards through sedimentary rock layers, forming a vertical tube that eventually erupts on the surface. Along the way, it encounters groundwater and creates a range of different types of rocks with combinations of metals and minerals generally unusual for the region. “
Additionally, a number of substances from deep within the Earth made their way to the surface, giving the area a number of unusual rocks and minerals.
Ugly Mountain, and its somewhat unattractive siblings Mole Hill and Trimble Knob, carry no threat in 2026. They do not lie dormant, or sleeping, like Mount St. Helens or Mount Rainier in Washington, waiting for the next eruption.
The volcanoes of Pendleton, Highland, and Rockingham counties died long ago. Their corpses serve not as active geological formations, but museum pieces rich with minerals created in place, but also that welled up from deep within the Earth.
Cutline.
A Google Earth image of Ugly Mountain ranges from the middle to the bottom of the photo. Brushy Fork Lake is near the top of the picture.
