I am not a geologist, but I have become fascinated with the St. Francois Mountains that are found on the Potosi-Fredericktown Ranger District.
This mountain range is relatively small in that it is mostly contained within the counties of Iron, Madison, Reynolds, St. Francois, and Washington.
The St. Francois Mountains were formed by volcanic activity over one billion years ago, making them much older than the Appalachians and Rockies. They are generally forest-covered with outcrops of rhyolite and granite bedrock.
The tallest peak is 1,772-foot Taum Sauk Mountain, which also happens to be the highest elevation in Missouri.
What I find most interesting about these mountains are the glades that occur as openings within the forest. Glades are open, rocky, barren areas with shallow soils that support unique communities of drought-adapted plants and animals, including species that are endangered.