Watch where you step—you are walking on fossils! The floors of Fernbank Museum are made of 40,000 limestone tiles, each containing fossil remains of animals that lived in a shallow reef more than 150 million years ago.
These tile floors are limestone that was formed during the Jurassic period, about 150 million years ago. Limestone often contains fossils because it starts out as soft mud. Millions of years ago, this soft mud was on an ocean floor where the remains of dead marine animals, like sponges and snails, sank into it. Over time, layers of this mud accumulated on the ocean floor. The deepest layers were packed down by the weight of mud on top and were cemented together into hard rock, trapping the remains of marine animals in the layers.
Find your way to the World of Shells at the far end of the Star Gallery for more information about ammonites and their living relative, the chambered nautilus. Go to the "Life in the Ancient Seas" gallery in A Walk Through Time in Georgia to find out more about how fossils form and to see examples of ancient sponges.