The US state of Georgia, situated in the south-eastern United States, boasts a rich geodiversity and a remarkable fossil record that spans millions of years. On the 18th March, 1976 the State Government of Georgia passed House Resolution No. 517-1385 designating the shark tooth, rather than a shark, as the State of Georgia's official fossil. The most notable sharks teeth in Georgia's fossil record belong to the Carcharocles megalodon - The Meg!.
From the Late Cretaceous through to the Eocene epoch between 100.5 – 33.9 million years ago the sea level rose and a combination of the Gulf of Mexico and Atlantic Ocean flooded and submerged a vast area of Georgia's Piedmont area.
The marine silt and mud deposited above the Piedmont in this marine environment formed the bays, lagoons, and estuaries along the Georgian coast as the sea extended diagonally across the south eastern portion of the state known as the Coastal Plain. The Coastal Plain province, is the the flattest provinces, stretches over 3,540 Km from Cape Cod to the Mexican border across several US States.
Sharks belong to a class of specialised Chondrichthyes whose subclasses of Elasmobranchii and Holocephali belong within the phylum Chordata. Chondrichthyes lack true bone unlike “bony fish” but instead they have evolved a skeleton made from cartilage a tough and flexible tissue found in the body of the shark.
Chondrichthyes are a group of cartilaginous fish that includes sharks, skates, rays, and chimeras who first appeared in the fossil record over 450 million years ago and during this intervening time they have survived several mass extinction events.
Because cartilage is a soft tissue it does not have the resilience of a mineralised extracellular matrix (ECM) such as true bone. Finding the fossil remains of a complete sharks are therefore very rare. However, the teeth of a shark are calcified and can be well preserved. In Georgia sharks teeth are found in great numbers as sharks constantly replace their teeth during their lifetime.
Among the shark fossil record of Georgia is a common shark’s tooth belonging to the now extinct slow swimming Goblin shark and also the the teeth of the Megatooth Sharks known as Carcharocles megalodon or generally referred to as Megalodons or Meg - meaning “big tooth”. Among the other sharks are the Sand Tiger Shark (Charcharis), Tiger Sharks (Galeocerdo), Snaggletooth Sharks (Hemipristis), Angel Sharks (Squatina) and Sawfish Sharks (Pristis).
The Carcharocles megalodon was an enormous shark that swam the oceans between 23 to 3.6 million years ago and would grow up to 20 meters and their teeth were over 10 cm in length. Today fossil hunters can find shark’s teeth in the muddy soil and clay based muds of the Coastal Plain shores, rivers and shallow waters.
Georgia's geodiversity is generally divided into three parts rooted in its diverse geological formations, each telling a unique story of the Earth's evolution. From the rugged Appalachian Mountains in the north to the coastal plains in the south, Georgia's geological history is a testament to the dynamic forces that have shaped the landscape over time.
In the northern part of the state, the Appalachian Mountains dominate the landscape. These ancient mountains were formed during the collision of the North American and African plates, resulting in the uplift of rock layers and the creation of the impressive ridges and valleys that characterise the region.
The Appalachian Mountains in Georgia are home to a variety of rock types, including metamorphic rocks such as schist and gneiss, providing a glimpse into the intense tectonic forces that shaped the area.
The Blue Ridge and Piedmont region of Georgia have no fossils because of this tectonic activity. Towards the north-west of the State near Cartersville towards the Appalachian Plateau region a shallow sea once existed forming shale and limestone deposits with fossil invertebrates including trilobites, fish, amphibians and reptiles. In the higher elevations of Lookout Mountain and Sand Mountain the shales contain fossils of plants.
Moving southward, the Piedmont region unfolds, characterised by gently rolling hills and extensive granite outcrops. This region is a transition zone between the mountains and the coastal plains, offering a mix of geological features. The granitic rocks of the Piedmont have played a crucial role in shaping the landscape, creating unique habitats and influencing soil composition.
The Coastal Plain, covering the southern part of Georgia, is a vast expanse of flat, low-lying terrain. Composed of sedimentary deposits, including sand, clay, and limestone, the Coastal Plain reflects the influence of ancient seas that once covered the region and rich in marine fossils. The sedimentary rocks of this area hold clues to past climates and environmental conditions, providing valuable insights into the fossil record of Georgia.
If you are visiting Georgia and are looking to explore Georgia and the Coastal Plain the following National Parks are recommended including Andersonville National Historical Site, Cumberland Island National Seashore, Fort Frederica National Monument, Fort Pulaski National Monument, Jimmy Carter National Historic Site. Additionally, visit the Georgia Museum of Natural History or the Fernbank Museum.