Monster Sharks Teeth, Fossils and Phosphate

By Ted Hunt

Question: What do the following have in common? A fossilized 7-inch tooth from an extinct shark as long as a bowling alley, the skull of a 10,000-year-old Saber-toothed tiger with 8-inch, dagger-like fangs and phosphate in a bag of fertilizer.

Answer: They all are found in Florida.    


Phosphate is a common element and is essential to all living things on the planet, plants and animals. It’s necessary for bone and teeth formation in humans and animals. It cannot be manufactured and there is no synthetic version — without phosphate, life would not exist.

Found naturally in ancient rock/ore deposits, phosphate is believed to have mineralized on the sea floor from the evaporation of seawater along with the skeletons and waste products of creatures living in the seas millions of years ago. It was the right natural cocktail to make phosphate rock. Then the seabed was lifted to the surface via tectonic uplift. The rock is surfaced, mined and pulverized, then an acid solution is applied to extract the phosphate. It has been used in a variety of products for more than 100 years.

Today it’s used in the production of pharmaceuticals, personal care products and industrial applications. Over 90% of all phosphate mined is used to enrich commercial fertilizers for food production. In a world which will be home to over 9 billion people by the middle of this century, producing enough food is likely to be a substantial challenge for humanity. Agriculture soils get depleted of phosphorus over years of crop use. Out of necessity, modern farming is reliant on the phosphate fertilizer industry. Even the casual gardener and homeowner uses phosphate. For example, a bag of 10-10-10 fertilizer contains 10% nitrogen, 10% phosphate/phosphorus and 10% potassium/potash.

Florida’s Phosphate Industry

Phosphate is found on most continents. In the United States, phosphate is mined in Florida, Idaho, North Carolina and Utah. Florida accounts for 80% of the phosphate used in fertilizer in the United States and 25% of the fertilizer used worldwide. The Florida phosphate belt runs from central Florida up the state for 150 miles and is 30 miles wide. Mining began in Florida in 1883 in a region extending from Alachua County (Gainesville) down through the Ocala area into Citrus County (Crystal River). It expanded into central Florida then into northern Florida in the 1960s. Florida has 27 phosphate mines spread over several counties, but only nine are currently active.

The others are in reserve when needed. The phosphate is found between 15 and 50 feet deep and the mines are open pits.

Florida’s Fossils and Bone Valley

Florida’s phosphate beds developed on the seafloor about 12 million years ago when oceans covered most of what is Florida today. Huge whales, massive sharks, dolphins and ancient sea creatures prowled the waters over submerged Florida. Over millions of years, these sea creatures died and were absorbed in the creation of phosphate deposits.

Eventually, the seas receded and the Florida peninsula with its large phosphate beds was now dry land. Advancing glaciers forced land mammals in North America, like saber-toothed tigers, towering mastodons, mammoths, 30-foot crocodiles, giant sloths and armadillos the size of a Volkswagen Beetle, as well as every type of bird, to flee to Florida. Here, they died, living only their skeletons, tusks and teeth to fossilize among the phosphate deposits.

There are no dinosaur fossils associated with the Florida phosphate formation. The extinction of the T. rex, raptors and the Brontosaurus occurred about 65 million years ago, well before the lands now known as Florida began to emerge from the sea.

The phosphate mines in Florida contain whole and fragments of fossilized land and marine animals. Florida has the distinction of being the richest state for vertebrate fossils from both land and marine animals east of the Mississippi River. The central Florida phosphate area with 1.3 million acres is aptly named Bone Valley.

Megalodon Sharks Teeth

When most of Florida was covered by ocean, the largest shark cruising above Gainesville, Tampa, Orlando and Miami was called Megalodon or Big Tooth. These monster sharks grew up to 60 feet in length, the length of a bowling alley lane. It weighed over 65 tons and had a massive jaw full of huge razor-sharp teeth that could reach over seven inches in length. It’s believed that Florida used to be a nursery area for the Megalodon, meaning where females would have their young. The great white shark is a tiny cousin that was often feasted upon by Megalodons that also ate whales.

When the Megalodons died, their cartilage skeletons and teeth settled on the seabed and phosphate deposits, and the teeth fossilized over millions of years. (Sharks do not have bones, only cartilage, which does not fossilize.) The oceans receded, exposing the Florida peninsula. The mammals that came later died, and their bones and teeth were quickly covered up by sand, mud, clay and phosphate rock, where they also fossilized. This is why you can still find Megalodon teeth mingled among other fossilized remains.


Want to Go Hunting?

You will be amazed at the variety of fossils and fossilized shark teeth that Florida has to offer. Not only are they found in phosphate beds but also in many of Florida’s creeks and rivers and on its beaches. Popular hunting grounds are abandoned phosphate mines, the Peace River (near Arcadia), and Venice Beach, which has been dubbed the “Shark Tooth Capital of the World” and even hosts The Venice Beach Sharks Tooth Festival each year. If you’re not one to venture out on your own, there are several companies that offer guided fossil hunts in north and central Florida and the Peace River area. While most of the mining areas are closed to the public, there are fossil clubs that have been granted permission to hunt on their properties. With luck, maybe you’ll find one of those 7-inch Meglatdon teeth or a Saber-tooth tiger fang. Happy hunting!