Simplify the following text for a Grade 11 native English-speaking person.
Original: The area surrounding Harrington Sound ( which lies to the south of Crystal Cave ) is of limestone formation and noted for many subterranean waterways , through which the waters of the sound empty into the Atlantic .
Simplified: The area around Harrington Sound ( which lies to the south of Crystal Cave ) is made of of limestone and has many underground waterways , through which the waters of the sound empty into the Atlantic .