Buried hills and hollows: the Ozarks' Precambrian landscape

There's a topographic mystery in the eastern Ozarks' St. Francois Mts: why are so many summits underlain by old Precambrian igneous rocks while the valleys are underlain by far younger sedimentary rocks? In this chapter of our Geology of the Ozarks series, we visit many different sites to explore possible explanations, demonstrating evidence that there's an ancient mountain range buried beneath this part of the modern Ozarks, its summits poking through a mantle of younger deposits. Like this video? Consider leaving us a tip via the Thanks button below this video, or through Ko-Fi (no account required): https://ko-fi.com/ozarkoutsider Geology of the Ozarks series playlist:    • Geology of the Ozarks   All graphic design, mapping, and imagery by Ozark Outsider unless otherwise noted: www.ozarkoutsider.com Chapters: 00:00 Intro 01:38 Elephant Rocks 02:48 Johnson's Shut-ins 03:41 Highway 72 roadcut 05:49 Taum Sauk hydroelectric plant 08:15 Taum Sauk Mountain 09:09 Regional 3D models & cross-section 10:39 Revisiting faulting 12:37 Effects on modern terrain 13:57 Summary & outro Resources cited in the video: Kisvarsanyi et al., 1981, Guidebook to the Geology and Ore Deposits of the St. Francois Mountains, Missouri: https://share.mo.gov/nr/mgs/MGSData/B... -Seeger & Palmer, 1998, Synsedimentary Tectonism in the St. Francois Mountains Region, Southeast Missouri (Association of Missouri Geologists field guide): http://www.missourigeologists.org/Ear...