Complex sentence: The stream, 1120 feet underground, is said to be fed both by rainwater and natural springs, and collect in a pool in the cave floor and then continues through the mountain until finally joining the Tennessee River at the base of Lookout Mountain.
Split into simpler sentences: The stream, 1120 feet underground, is fed both by rainwater and natural springs. It collects in a pool in the cave floor and then continues through the mountain until finally joining the Tennessee River at the base of Lookout Mountain.