Uploaded June 2026 | Updated September 2026, 4 days ago

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Check out this link to see some great research on this area by Mark Evans:
researchgate.net/publication/321043727_THE_STRUCTURAL_GEOMETRY_AND_DEVELOPMENT_OF_THE_CENTRAL_AND_EASTERN_PART_OF_THE_PENNSYLVANIA_SALIENT

The crazy mountain ridges of Pennsylvania's Valley and Ridge are legitimately world famous, particularly among geologists. Their patterns are unique within North America and arguably the world, and they owe their existence to huge, ancient geologic structures made visible by millions of years of erosion. This video talks about the structural geology that produces the mountain patterns, using drawings and real sandbox models.