OVERVIEW
Florida is a massive carbonate platform that has seen numerous sea level change over millions of years. The current Florida land mass emerged during the Oligocene Epoch (33 - 24 mya) due to a worldwide drop in sea levels and the first terrestrial vertebrates date to this time period. During the ensuing Miocene Epoch (23 – 5.3 mya), large deposits of phosphates formed in various areas of Florida and are now commercially mined. These beds contain some of the richest concentrations of vertebrate fossil material in the state, including the remains of horses, mastodons, and even sabre-tooth cats. The offshore areas are represented by the remains of whales, dugongs, and the iconic Megalodon shark, which obtained lengths in excess of 50'. The teeth from this species of shark, Otodus megalodon, are perhaps the best known and certainly one of the most highly prized fossils of Florida.
The Pliocene Epoch (5.3 – 2.6 mya) saw the connection of North and South America and thus the influx of new animal species, including camels, sloths, and even giant armadillos. And, with the Gulf of Mexico now separated from the Pacific Ocean, an extremely diverse molluscan fauna developed in the waters of SW Florida as well. The Pleistocene Epoch (2.6 mya-10,000 years ago) saw numerous fluctuations in sea level due to periods of glaciation. Land animals present in Florida at this time include the wooly mammoth, dire wolves, giant beavers, and other unique large mammals. Finally, in the late Pleistocene, humans arrived in Florida, which coincided with the extinction of many of the larger Pleistocene mammals.
Because the Florida platform is primarily limestone, most of the minerals to be found are fossil-related. The state stone is agatized coral, which can be found in the Tampa Bay area and various rivers as far north as Georgia. Also well-known are the colorful dog-tooth calcite crystals found within fossil clams in the Lake Okeechobee area. interestingly, many of these fossil clams occur within a matrix that is extremely hard due to it being mineralized with titanium. Similarly, the shark teeth found in the phosphate areas (called the Bone Valley area) are very colorful due to phosphate mineralization.
For a more detailed overview of Florida's geologic history, click on this link:
https://edis.ifas.ufl.edu/publication/UW208
AGATIZED CORAL IS THE FLORIDA STATE STONE