What Is Limestone?   View of the fossil beds from the Interpretive Center Deck Limestone is a type of sedimentary rock made of calcium carbonate. Limestone can be composed of skeletal remains of organisms, chemically precipitated from sea water that is super-saturated with calcium carbonate or a combination of both. The limestone at the Falls of the Ohio is composed of skeletal remains from countless numbers of corals, stromatoporoid sponges, echinoderms, brachiopods, mollusks, arthropods, and microscopic organisms. It is called the Jeffersonville Limestone (after the city of Jeffersonville which was originally at the upper end of the Falls) and dates from the latest Early Let's go down the steps and explore the fossil beds! Devonian to Middle Devonian. (Geologists call this Emsian and Eifelian Age - 387 to about 380 million years ago). 201 West Riverside Dr. • Clarksville, IN 47129 • (812) 280-9970 • park@fallsoftheohio.org Design and Hosting by Natural Concepts, Inc.