Geology Merit Badge Trail       Introduction Plate Tectonics Time Scale and History Formation of the Ouachitas Faults and Earthquakes Fossils Geologic features Environmental Geology Fossil Fuels Careers

The Stories Fossils Tell   Fossils are the remains of plants or animals that have turned into stone. They may be bones or teeth or shells, an outline, or a shape pressed into the rock. Footprints and droppings have been found as fossils, too. For a fossil to be made, the dead plant or animal has to be buried rapidly by sediment. The soft parts rot away, but the harder parts are preserved and hardened by the minerals of the dirt and mud covering it. Fossilization also occurs when the parts of the organism are dissolved away to leave an impression in the mud. The impression can act like a mold, and the next layer of sediment becomes cast in the same shape as the original living thing - just like you can make a plaster cast of your own or an animal footprint in the ground. As plants and animals die and are buried by mud and dirt, layers build up, with the older organisms on the bottom. By studying the layers, paleontologists (scientists who study fossils) can get clues to how living things have changed over the eons. These layers are also very important clues to dating the ages of the rocks.         The next page is a Few Pictures of Geologic Features Ch 5 , page 6 Contact the authors of Rockhounding Arkansas revised October 1998 ©Rockhounding Arkansas 1998 http://rockhoundingAR.com