FLINT RIDGE CAVE SYSTEM

a complex of caves and underground rivers in west-central Kentucky, U.S. The surveyed areas of the system are entirely within Mammoth Cave National Park (q.v.). The caverns are interconnected to a great extent, and some of them have been explored. Flint Ridge is a plateau capped by resistant sandstone and shale layers, underlain by hundreds of feet of limestone. Acidic water has eaten into the limestone without affecting the overlying sandstone and shale, producing the underground caves. Prominent features within the caverns include extensive sulfate mineral formations, stalactites, stalagmites, and archaeological artifacts. The system's hub and gateway is Floyd Collins' Crystal Cave, named for its discoverer (1917). In 1972 a connection was discovered between the Mammoth and Flint Ridge cave systems, making them by far the longest continuous cave system in the world.