Unpack the Past - Fossils
Part 1: What is a Fossil?
What is a fossil? They are the remains of plants and animals that lived long ago. Remains have to be a minimum of 10,000 years old (!) to be considered a fossil. Sometimes, it is the hard part of the animal, like shell, teeth, or bone, that is preserved. It can be wood, seeds, or insects, too. Footprints, leaves, eggs or burrows (a tunnel) can be fossils as well. In order for something to become fossilized, it must be buried quickly, usually by mud or sand.
Southern Indiana, along the Ohio River, is an excellent place to look for fossils. The area was a warm sea during the Paleozoic Era (544-528 million years ago). It was filled with plants and small marine animals.
During the Mesozoic Era (248-65 m.y.a.), or the “Age of Reptiles”, there were reptiles along with plants and marine life. No dinosaur remains have ever been found in Southern Indiana. There was a massive land mass shift and evidence of most life during this time was lost.
The Cenozoic Era (65 m.y.a.) was called “The Age of Mammals”. During this time, mammals became the biggest population of large land animals. Birds appeared as well. Again, erosion during climate upheavals make fossils from this era scarce.
During the “Ice Age”, or Pleistocene Epoch (1.8 m.y.a.- 8,000 years ago), many of the huge land mammals became extinct. Ice Age glaciers destroyed or buried remains further north. Most of the recent fossils discovered have been in caves, swamps, bogs, and washed out river beds. Almost all of the fossils we recover from this time period are of sea life and are easy to find.
Part 2: Fossils in Indiana
Some fossils you may find:
They look like flowers but are really animals anchored to the sea floor by a segmented stem and root structure. It is common to find the stem portion in fossil form.
Animals that include insects, spiders, horseshoe crabs, centipedes, millipedes, pill bugs (roly poly’s), lobsters, crayfish, and the extinct trilobite. Horseshoe crabs are the closest living relative to a trilobite. They ranged from an inch or two long to nearly two feet and existed for nearly 300 million years. Coelenterates (see len ter ates) Include jellies, sea anemones, and corals. The presence of fossil coral in Indiana proves that the seas that covered Indiana during the Paleozoic era were at times shallow and tropical.
Bryozoans built colonies that were either attached to the sea floor branching out like antlers, or grew over the shells of other ocean animals. Their lifestyle was very similar to corals.
Brachiopod shells are probably the most commonly collected fossils in Southern Indiana. Brachiopods are a type of marine invertebrate (lacking a backbone) animal. Their shells have two valves attached along a hinge, similar to clams.
Part 3: Mammoth
These fossils were found here in Madison at the foot of Hanging Rock Hill (Cragmont Street) in 1919 by W.O. Wycroft. A letter from Mr. Wycroft states that he was a 14-year-old boy when he found the artifacts. The fossils were “quite crumbly” so his father shellacked them (a type of glue) so they wouldn’t fall apart. We believe they are the remains of a mastodon, as there have been other similar fossils found in Scottsburg. These items were donated the Historical Society in 1988.
This snail shell is NOT a fossil. It hasn’t been buried in the mud and was probably recently occupied.
These are fish bones, and they are not fossils, either. They are most likely the remains of a bird’s dinner.
Other treasures you may find along the rivers and streams in Indiana:
Native American artifacts from the various local tribes such as arrowheads, hatchet or axe heads, fishing hooks.
You may find geodes, which have beautiful crystals inside when broken open.
If you look along the river down by Ferry Street, you may be lucky enough to find mussel shells, which have had buttons punched out of them. The Pearl Button Factory dredged the Ohio River for mussels, which had clothing buttons punched from them. Women would sew the buttons onto cards for extra spending money. Most of the shells have quite a bit of erosion on them, but you can still see where the holes were punched. We have an excellent exhibit on mussel shells in the museum.