Sources
Shenandoah National Park
https://www.nps.gov/articles/000/shenandoah-valley-geology.htm
https://www.usgs.gov/geology-and-ecology-of-national-parks/geology-shenandoah-national-park
https://www.nps.gov/shen/learn/historyculture/places.htm
https://www.goshenandoah.com/explore/shenandoah-history
https://www.snptrust.org/about-us/mission-history/shenandoah-history/
https://www.nationalgeographic.com/travel/national-parks/article/shenandoah-national-park
New River Gorge National Park
https://www.nps.gov/neri/learn/nature/geologicformations.htm
https://www.nps.gov/neri/learn/historyculture/stories.htm
Great Smoky Mountains National Park
https://www.nps.gov/articles/greatsmoky.htm
Mammoth Cave National Park
https://www.nps.gov/maca/learn/nature/geology.htm
https://www.usgs.gov/geology-and-ecology-of-national-parks/geology-mammoth-cave-national-park
https://www.britannica.com/place/Mammoth-Cave-National-Park
https://www.nps.gov/articles/000/saltpetre-mining.htm