1. Calcite Reaction Calcite is composed of calcium, carbon and oxygen CaCO 3 = Calcium Carbonate Found naturally as calcite and chalk Acid reacts and gives off carbon dioxide (CO 2 )

2. Formation of limestone Calcium carbonate becomes so concentrated in the sea water that calcite crystallizes out of the sea water to form limestone. Most limestone forms with organisms usually found at the bottom of shallow seas.

3. Fossil Groups Corals Sea creatures Live solitary or in colonies Brachiopods Shellfish Attached to sea bottom Bivalves Shellfish Two hinged shells Examples are clams and mussels Gastropods Snail like animals Single shell

4. More Fossil Groups Trilobites Extinct sea creatures Earliest form of arthropod Crinoids Known as sea lilies Marine creatures that attach to a seabed Plant Fossils Ferns are typical of floodplains and swamps

5. Fossil Evidence Kaibab Formation Braciopods/ sponges 260 million years old Toroweap formation Brachiopods, bryozoans 260 million years old

6. Coconino Sandstone Fossils of animal tracks Lizard tracks 270 million years old Hermit Shale Fern and insect wings 275 million years old

7. Supai Group No Fossils 325-275 million years old Redwall Limestone Braciopods 360 million years old

8. Temple Butte Limestone Primitive armored fish, conodonts 385 Million Years Muav Limestone Brachiopods, trilobites 530 million years old Bright Angel Shale Trilobites, burrows, tracks and trails of snails worms and trilobites 540 million years old Arthropods- insects, arachnids, crustatians

9. Tapeats Sandstone Tubeworm burrows 545 million years old Vishnu Schist No fossils 1.7 billion years old