The Chain of Lakes is an impressive natural feature created by a receding lobe of the great Cary Glacier which melted approximately 12,500 years ago, leaving irregular hills and valleys. Organic matter plus deposits of sand, gravel and rocks trapped in the mass fell to the bottom of the valleys, creating their unique terrain. Great chunks of ice melted in the deep pits, forming today's lakes of the Chain. The melting ice uncovered natural springs opened by the movement of the glacier. These natural springs feed the lakes with remarkably pure water, and natural filtration keeps the lakes crystal clear by continually releasing fresh spring water while older water empties through the Crystal River outlet.