Tennessee, extending 500 diagonal miles between Bristol and Memphis, cuts across numerous rock types, from the deformed gneiss of the Blue Ridge along the North Carolina border to the young sediments exposed in the Chickasaw Bluffs that rise 100 feet above the Mississippi River floodplain. The state65533s more than 1 billion years of geologic history includes continental collisions that built enormous mountains and rifting forces that almost split the ancient continent apart. The geologic processes are still at work in Tennessee, with sinkholes claiming land in areas of limestone, rivers eroding sediment and shifting channels, and some of North America65533s largest earthquakes occurring every 500 years on the ancient rift faults near Reelfoot Lake. pLearn about unusual meteor impact sites on the Highland Rim of Middle Tennessee, the world-famous fossils in the Coon Creek Formation, and the source of saltpeter used for gunpowder in the Civil War. An extensive section on Great Smoky Mou