Junior Trailblazers: Flori-Dough Fossils

Florida is known for its unique geological history, which has made it a prime location for discovering and studying fossils. A fossil is the preserved remains or the impression of animals and plants that lived a very long time ago.  Fossils are not exactly the remains of the animal or plant itself- they are rocks! Bones, shells, feathers, and leaves can all become fossils.

As a peninsula state surrounded by water, Florida has mostly been underwater for millions of years, resulting in the preservation of various marine creatures that existed during different geologic epochs. The state’s most famous fossils include dugongs, dire wolves, mammoths, horses, and giant land tortoises that date back to the Pleistocene period, which ended about 10,000 years ago.

Most fossils are formed when a plant or animal dies and is rapidly buried in mud and silt. The soft parts of the plants and animals break down leaving the hard bones or shells behind. Over time, small particles called sediment build up over the top and harden into rock.  These fossil remains are preserved to find thousands of years later and be studied by scientists and admired by people like you and me.

Some fossils found in Florida - can you guess what is a turtle shell? a horse tooth? or stingray mouth plates? 

Sometimes, only the activity of the plants and animals are left behind, and these types of fossil are called trace fossils.  Think about footprints, burrows, trails, food remains, etc. Some other ways fossilization can happen is through rapid freezing, or being preserved in amber (the resin of trees).

Trace fossils showing signs of a crab feeding; today you can see similar markings in the sand from fiddler crabs - have to seen these on the bobcat trail at Upper Tampa Bay Conservation Park? 

Fossilized Dilophosaurus track in Utah, photo by Phil Konstantin. 

There are several environmental factors necessary for the formation of fossils, including:

1. Rapid burial: The organism must be buried quickly after death to prevent decomposition and scavenging by other animals.

2. Sediment: The organism must be buried in sediment (such as sand, mud, or silt) that will later harden into rock.

3. Lack of oxygen: The sediment must be free of oxygen to prevent rapid decay of the organism.

4. Pressure and heat: Over time, the weight of the sediment will compress the organism and cause it to fossilize. Heat and pressure from deeper layers of the earth will help to further harden the sediment into rock.

5. Water: Groundwater that contains minerals can flow through the sediment, replacing the organic material with minerals and creating a fossil.

These steps can take millions of years and only a small fraction of organisms that have ever lived have been preserved as fossils.

Most of Florida’s fossils have been discovered in the state’s rivers, streams, and coastal areas. The Peace River, south of us in Charlotte County, has become a popular site for amateur and professional fossil hunters due to the large concentration of marine and land animal bones that can be found in its banks. Additionally, fossilized shark teeth have become popular souvenirs for visitors to the state’s beaches. Many museums and educational centers across the state also contain exhibits showcasing Florida’s rich fossil history.

Fossils from the Liesey Shell Pit include a Saber Toothed Cat (Smilodon gracilis), Tapir Jaw, and Llama Jaw. 
Courtesy of the Florida Museum

Although fossil hunting has become a popular activity in Florida, it is important to note that many of these precious specimens are protected by law, and digging without permits is prohibited on protected lands like our Conservation Parks and Nature Preserves – know before you go. However, the Paleo Preserve at Camp Bayou has a site where kids are able to dig for their own fossils! 

Overall, Florida is a treasure trove for those interested in the natural history of the state and its prehistoric inhabitants, making it an exciting and educational destination for fossil enthusiasts.

Since we don’t have time to spend a millennia making fossils, let’s make salt-dough fossils at home!

Flori-Dough Fossils

You Will Need:

·         2 cups all-purpose bleached flour

·         1 cup of salt

·         1 cup of warm water

·         Round cookie cutter

·         Small plastic dinosaurs, animals, or other items of your choice

How to make a Flori-Dough Fossil

1. Combine all the dry ingredients in a bowl and form a dip in the center.

2. Add the warm water to the dry ingredients and mix together until it forms a dough.

TIP: If you notice the salt dough looks a little runny, allow the mixture to rest for a few moments. That will give the salt a chance to absorb the extra moisture. 

3.  Roll the dough to ¼ inch thick or so and cut out round shapes with a circle cookie cutter.

4.  Take your animals or dinosaurs and press the feet or bodies into the salt dough, stamping them.

5.  Place on a baking sheet and bake at 325* for 15-30 minutes (should be hard, but not seem burnt). Alternatively, you can air-dry them for 24-48 hours. 

6.  When the salt dough fossils are hard, use them to create your own paleo dig.  If you made them with friends or family, trade and try to match each fossil to the right figure. Did you make body fossils or trace fossils? Can you try this again with objects you find outside, like acorns or leaves?  

Tip: For a more "realistic" look, you can add coffee grounds or sand to the dough, or replace the water with cold coffee! 

You can see fossils in person at Camp Bayou’s Paleo Preserve.

Learn about the Leisey Shell Pit here in Hillsborough County.

Florida fossil sheets by Russell Brown / Florida Fossil Hunters.