Signs of Florida’s Ancient Past

It may be hard to believe, but life in 21st century panhandle Florida is fairly constant and predictable, at least from a geological perspective. The seasons change with regularity as the sun, moon and stars relocate on schedule.

Roadways in cities and towns clog up twice daily during the week. Holidays come and go as leaves on the calendar fall into history.

The old-timers will reminisce about how things were different in the 1960s, ‘50s or earlier, but there were still people, cars, houses, trees, and families and roads with familiar names. It was different, but not that much different.

The evidence of a different north Florida is still present today, but rarely recognized. All one has to do is look underfoot for the confirmation of a time when there was a very different reality.

A silent testament to the residents who once inhabited the region, calcium encrusted fossils of marine life are still commonly found today.

The unwritten history of the region is recorded in the fossil record of the area’s limestone and with relics often darkened by tannic acid from trees. The remains from this prehistoric era are not dinosaurs which were long gone before many of the area’s fossils were produced.

From a geological standpoint, the Florida landmass known today is a very recent occurrence. It is thought glacial activity caused the Gulf of Mexico to retreat several times, exposing what would become Florida during the Pliocene Epoch.

The development of fossils was aided by environmental factors present at the time. First, the area was geologically tranquil for 25 to 30 million years.

While Florida was submerged, the shallow bays became stable collection points for the remains of sea-life which died. The ebb and flow of tides covered and preserved the hard tissues which were based on calcium.

Once the retreating sea left dry land, no mountains were pushed up by subterranean plates which would have changed rainfall patterns or caused rushing waters. The steep inclines and scouring water movement would have removed the potential fossil remains.

There were no volcanoes which would have covered large areas with lava and ash, deeply burying anything on the surface. Nor were there earthquakes which would have dropped large chunks into the gulf.

Limestone deposits close to the surface also aided the process. Over time some of the deposits dissolved and produced caves and sinkholes.

Animals became ensnared in these natural traps and, over time fossilized. Their hard tissue was preserved along with rare examples of tree bark which absorbed minerals as the cellulose dissolved.

If the long-term conditions were suitable and the shell had a high concentration of calcium carbonate, it could survive to the present. If not, then only the imprint had the potential to last.

Shark’s teeth are the most commonly encountered Florida fossil. In many cases, only the tooth’s color has been changed and it is still as sharp as when the shark was using it.

Shells and shell imprints, sea urchins, and bones from fish and marine mammals are also in the soil. Most are broken, but occasionally a complete specimen is encountered.

As new roads are laid and houses built, it is good to remember that once these were the domain of sea creatures. It will be interesting to see what kind of “fossils” of the 21st century remain to be found in the future.

About the author
Les Harrison

Les Harrison is a longtime resident of north Florida, having attended public schools in three counties. He has a Bachelor Degree from the University of Florida in Journalism and a Master’s of Science from Auburn University in Agricultural Economics. He is the author of more than 2000 newspaper and magazine stories and journal articles. During his career, he held positions in private, government and educational (university level) sectors. He holds the title of Extension Agent Emeritus. He can be reached at harrison.gl@gmail.com.

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