One type of mountain here in the eastern USA that I quite enjoy looking at and hiking are monadnocks. Simply, a monadnock is an isolated area of relatively high terrain surrounded by a larger area of relatively low terrain. Generally, this type of mountain is formed when tough caprock resists erosion in a limited area while the lands around it are worn down and the softer material is sent toward the coastal plains. Almost all of the monadnocks here in the southern USA were formed this way.
And of the southern monadnocks, one of my favorites is Pilot Mountain. In a bit of trivia, Andy Griffith used the name by switching the words and transforming it to the town, "Mount Pilot" in the old TV series from the early 60s.
The caprock that caused this mountain to be left behind while the Piedmont around it was washed down to the Atlantic is quartzite. It's really tough material that overlies softer sediments. Pilot Mountain is one of a series of similar such formations in the area that form a separate and isolated range called the Sauratown Mountains. But Pilot Mountain stands apart even from the other Sauratown peaks. It rises an impressive 1,400 feet above the surrounding plains and stands as a remarkable and instantly recognizable mountain for many miles in every direction. It's even visible and instantly identified from the high Blue Ridge far to the west.
The last time I visted the mountain, the trail around the summit was closed for upfitting. I'm hoping to return there very soon so that I can check out that trail and snap the views I was denied on that trip. A climb to the very summit would be good, but that part of the mountain is permanently closed to human access because of rare plants and birds that exist there. Pilot Mountain is one of only a few peaks in the eastern USA whose summit cannot be accessed by walking. The walls that surround the top are sheer and present Class III and Class IV climbing.