https://phys.org/news/2018-05-landscape-evolution-intrinsic-ancient-mountain.html > Gallen's study, which analyzed peaks in two of the most visited national parks in the United States, the Blue Ridge Parkway and the Great Smoky Mountains, puts to rest a century-old debate over the westward course of the Tennessee River. > Based on the findings, Gallen said this river system diverted from a more direct southerly route to the Gulf of Mexico about 10 million years ago. The river's reorganization can be traced to erosion and is reflected in the DNA of fish and salamanders in the waterway. This suggests a link between mountainous landscape dynamics and the evolution and diversity of aquatic species.